فهرست مطالب

  • پیاپی 31 (پاییز 1398)
  • تاریخ انتشار: 1399/02/30
  • تعداد عناوین: 12
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  • منصور پروین*، رامین حاتمی فرد صفحات 1-18

    کارست مجموعه ای از فرایندهای زمین شناسی و پدیده های حاصل از انحلال سنگ ها درنتیجه بازشدگی ها، تخریب و تجزیه سنگ ها است که رژیم هیدرولوژیکی، شبکه زهکشی و لندفرم های خاص را به وجود می آورد. هدف این پژوهش ارزیابی تاثیر توسعه ژیومورفولوژی کارست و رخداد خشکسالی بر ویژگی های کمی و کیفی آبخوان های کارستی تاقدیس گرین می باشد. برای این منظور چشمه های امیر، چناره، آهنگران، لاغری و تیمور در یک دوره 15 ساله (1394-1380) مورد مطالعه قرار گرفتند. با استفاده از روش  SPI میزان خشکسالی و تاثیر آن در منطقه ارزیابی گردید. همچنین میزان توسعه کارست در هر آبخوان براساس روش مالیک و وجکتوا مشخص گردید. با توجه به ارزیابی های هیدرودینامیکی، درجه توسعه یافتگی کارست در آبخوان چشمه های امیر و چناره بین 2/5 تا 2/7 بوده و دارای سیستم غالب جریان افشان و زیر رژیم های خطی می باشند. آبخوان چشمه آهنگران دارای درجه توسعه کارست 4/3 بوده و سیستم جریان آن ها از نوع مجرایی- افشان می باشد. آبخوان چشمه های،لاغری و تیمور دارای درجه توسعه کارست 5/5 و سیستم جریان مجرایی می باشد. با توجه به توسعه متفاوت ژیومورفولوژی کارست می توان گفت که در چشمه های لاغری و تیمور به علت پایین بودن اثر حافظه و توسعه یافتگی آبخوان، واکنش دبی به تغییرات بارشی دارای تاخیر زمانی کوتاه مدت بوده است. اما در چشمه های امیر و چناره به علت توسعه اندک کارست، تاثیر خشکسالی با تاخیر حدود 24 ماهه مواجه بوده است. بر اساس نتایج هیدروشیمیایی بالاترین و پایین ترین مقادیر TDSبه ترتیب در چشمه های چناره و آهنگران وجود دارد. همچنین بالاترین و پایین ترین مقادیر THبه ترتیب مربوط به چشمه های آهنگران و تیمور بوده است.

    کلیدواژگان: ژئومورفولوژی، تاقدیس گرین، کارست، خشکسالی، SPI
  • مریم بیاتی خطیبی*، بهروز ساری صراف صفحات 19-39

    هرگونه تغییر در شرایط طبیعی موجب تغییر در فرایندهای فرسایشی و همچنین تغییر در نوع مخاطرات محیطی می شود و این تغییرات درنهایت موجب تغییر در ویژگی های شیمیایی و فیزیکی آبرفت ها و در دانه بندی، رنگ و شکل بندی لایه ها می گردد. یکی از شاخصه های تغییرات محیطی، تغییر در میزان سولفات در سازندها است. تغییرات میزان سولفات و کلرید در سازندها نشانه مخاطرات محیطی در محدوده مورد مطالعه است زمانی که میزان آن از آستانه های مشخص فراتر می رود، به معنی آن است که شرایط سخت محیطی و یا خشکی بر محیط حاکمیت یافته است. در این مقاله به منظور بررسی تغییرات محیطی در گذشته، سعی شد در محدوده های مشخص که داده ها مورد دسترس و لایه ها قابل تفسیر و از نظر باستان شناسی نیز از اهمیت زیادی برخوردار بودند، چینه ها، لایه و همچنین ویژگی های شیمیایی نمونه های برداشت شده، مورد بررسی قرار گیرد و برای پیگیری تغییرات از داده های مربوط به حفاری در محدوده شهر تبریز بهره گیری گردید و با استفاده از داده های پالیوپدولوژیک و روش هایsd  اطلاعات لازم کسب شد. نتایج حاصل از بررسی مقدار کلرید در بخش های مختلف محدوده مورد مطالعه نشان می دهد که مقدار کلرید در بخش هایی از محدوده از 8000 ppm بیشتر شده است، نوسان در میزان کلرید بخصوص وقوع تغییرات محسوس در آن به معنی وقوع تغییرات شدید در شرایط محیطی به ویژه تشدید خشکی محیط است. نتایج حاصل از استناد به افزایش میزان کلرید در نمونه های برداشت شده از بخش های مختلف دشت تبریز نشان می دهد که این محدوده در دوره پلیستوسن با سرمایش محیط مواجه شده است. بررسی ترکیب دانه بندی در   نمونه های تهیه شده در محدوده میدان ساعت نشان می دهد که، تجمع دانه بندی ریز در عمق های پایین تر به 100 درصد می رسد. دوباره در لایه های تقریبا نزدیک به سطح، به درصد ریزدانه ها افزوده می شود. البته حضور ماسه های بادی در اعماق 15 متری تا 35 متری قابل ملاحظه است که حضور ماسه های بادی و ترکیب ریزدانه ای سازندها از حاکمیت شرایط خشک در محیط حکایت می کند.

    کلیدواژگان: مخاطرات محیطی، پالئوپدولوژیک، تغییرات اقلیمی گذشته، دشت تبریز
  • میثم یاری، سمیه سلطانی گردفرامرزی*، محسن قاسمی صفحات 41-58

    تغییرات کاربری اراضی موجب تغییر مولفه های مختلف چرخه هیدرولوژیکی می شوند. هدف از پژوهش حاضر بررسی تاثیر کاربری های مختلف و تغییرات آن طی سال های 1371، 1381 و 1391 بر روی سیلاب و نوسانات آب زیرزمینی در بخشی از حوضه آبخیز قره سو اردبیل است. در ابتدا نقشه های کاربری اراضی و شماره منحنی در سال های مذکور تهیه و روند تغییرات کاربری اراضی مطالعه و تاثیر آن بر سطح تراز آب زیرزمینی و رواناب بررسی و سپس شبیه سازی سیلاب با استفاده از مدل HEC-HMS انجام گردید. نتایج نشان داد که در طول دوره مورد مطالعه، مساحت کاربری جنگل، زراعت آبی و زمین بایر به ترتیب 2/54، 16/69و 1/19 درصد کاهش و مساحت کاربری مرتع، زراعت دیم و مناطق مسکونی به ترتیب 74/5، 39/12 و 29/2 درصد افزایش یافته است. با توجه به مقدار شماره منحنی و شبیه سازی سیلاب، نتایج به دست آمده نشان داد که دبی اوج و حجم سیلاب به ترتیب با افزایش 9/49 و 6/67 درصدی رو به رو شده است. درنهایت این تغییرات باعث کاهش سطح آب زیرزمینی به میزان 6/14 متر (39/06درصد) در طول دوره آماری 30 ساله شده است. محاسبه ضریب همبستگی بین کاربری های مختلف و حجم سیلاب و سطح آب زیرزمینی نشان داد که این متغیرها با کاربری های مرتع، زراعت دیم و مناطق مسکونی رابطه ی مستقیم دارند، درحالی که با کاربری های جنگل، زراعت آبی و زمین بایر دارای رابطه ی معکوس می باشند.

    کلیدواژگان: کاربری اراضی، سیلاب، آب زیرزمینی، همبستگی، حوضه آبخیز قره سو اردبیل
  • محمدحسین رضائی مقدم*، میراسدالله حجازی، عبدالله بهبودی صفحات 59-75

    شبیه سازی جریان رودخانه ها، پیش بینی رفتار هیدرولوژیکی حوضه های آبریز و درک درست از مولفه های مختلف چرخه هیدرولوژیکی برای برنامه ریزی و حفاظت از منابع آبی ضرورت دارد. از طرف دیگر، نبود برآورد مناسب رواناب حاصل از بارش در حوضه های آبریز، مدیریت بهینه منابع آب به ویژه مدیریت بهره برداری از سدها و شبکه آب رسانی را دچار مشکل می نماید. در این پژوهش، بیلان آبی حوضه آبریز لنبران با استفاده از مدل SWAT شبیه سازی شد. برای واسنجی و اعتبارسنجی مدل SWAT از دو روش GLUE و SUFI-2 استفاده شد. نتایج حاصل با استفاده از چهار معیار ارزیابی مدل ها شامل معیار نش ساتکلیف، ضریب تبیین، نسبت باقیمانده میانگین مربعات خطا به انحراف از معیار داده های مشاهداتی و دو فاکتور p-factor و r-factor مقایسه شدند. نتایج حاصل از کاربرد این دو روش نشان داد که روش SUFI-2 دارای الگوریتم موترتری برای واسنجی و تعیین عدم قطعیت مدل در این حوضه است. بر این اساس با اطمینان بیشتری می توان از مدل SWAT واسنجی شده با الگوریتم SUFI-2 در مدیریت منابع آب، کمی سازی سناریوهای تغییر اقلیم و تغییر کاربری در داخل حوضه استفاده کرد.

    کلیدواژگان: لنبرا ن چای، روش SUFI-2، واسنجی، مدل SWAT، عدم قطعیت
  • عباس ممقانی، محسن زارع احمدآباد*، مهران مقصودی صفحات 77-95

    در قسمت های شمال غرب حوضه آبریز دریاچه ارومیه در بخش قوم تپه صوفیان، تپه های ماسه ای به صورت محدود قابل مشاهده است که پس از بررسی های علمی صورت گرفته علت اصلی شکل گیری آن ها برآیند فعالیت بادهای غالب و ماسه های ریزدانه است. هدف غایی این تحقیق بررسی کانی شناسی در منشا یابی و تحلیل مقطع تپه های ماسه ای در قم تپه صوفیان است. با توجه به اهمیت تحلیل آماری باد در منطقه، آمار باد 2 ایستگاه پیرامونی اخذ و از طریق ترسیم گلبادها، تجزیه وتحلیل شده است. تغییر راستای وزش فصلی این بادها در محدوده مورد مطالعه، نتیجه تاثیر شرایط کم فشار حاکم در چاله دریاچه ارومیه و دشت تبریز است. اقلیم خشک و نیمه خشک، فقر پوشش گیاهی و همواری نسبی سطح زمین از مهم ترین عواملی  هستند که باعث غلبه فرایندهای فرسایش بادی در منطقه قوم تپه شده اند. ماسه های نمونه برداری شده از 5 مقطع، از طریق آزمایش های XRF و XRD تجزیه وتحلیل شده است و درصد زیاد کانی های آذرین (کانی سنگین) در نمونه ها، زیاد بودن میانه قطر نمونه ها (293 میکرون)، رابطه میانگین قطر ذرات با فاصله حمل (کمتر از 20 کیلومتر)، ضرایب گردشدگی نیمه زاویه دار در اکثر نمونه ها مورد تایید است. همچنین نمونه ها برآیندی از حمل آن ها توسط باد و آب بوده و نشان دهنده ارتباط منطقی مورفوسکوپی دانه هاست به دلیل فاصله زمانی حمل با منشا رسوبات تپه های ماسه ای نزدیک و از سطوح مخروط افکنه (دشتسر) و اراضی زراعی متروکه واقع در نواحی شرق و جنوب و همچنین بستر رودخانه های قدیمی در بخش جنوب شرقی منطقه است. نتایج تحقیق نشان می دهد بالا بودن نسبت ذرات ماسه های کمتر از 250 میکرون، ضعف پوشش گیاهی و جهت بادهای غالب محلی، محیطی مناسب برای گسترش فرسایش بادی مهیا می سازد، به طوری که با کاهش این نسبت از شدت فرسایش نیز کاسته می شود. این مورد با بررسی نمونه های دانه سنجی، عملیات میدانی و مشاهده عکس های هوایی نیز تایید می گردد.

    کلیدواژگان: تپه های ماسه ای، قوم تپه صوفیان، تحلیل مقطع، آزمایش های XRF و XRD
  • نعمت مال امیری، علیرضا راشکی*، سیدرضا حسین زاده، مهناز جهادی طرق صفحات 97-110

    گردوغبار را می توان یک پدیده طبیعی در نظر گرفت که در کشور ایران و به ویژه در استان خوزستان بروز آن در چند دهه اخیر دارای توالی بیشتری بوده است. بدین منظور در این پژوهش، شناسایی منابع تامین کننده گردوغبارهای غرب خوزستان هدف گذاری گردید. بر این اساس از تصاویر ماهواره ای مودیس سنجده ترا برای استخراج شاخص بهبود یافته دمای روشنایی گردوغبار (BADI) در سه گردوغبار متوالی در زمستان 1396 و بهار 1397 (2018) بهره برده شد. نتایج شاخص بکار رفته روشن ساخت که مناطق مختلفی در داخل و خارج کشور تامین کننده ذرات گردوغبار در غرب استان خوزستان می باشند. بر این اساس در اولین گردوغبار به تاریخ 20/1/2018 مشاهده شد که چشمه اصلی گردوغبار در نواحی خشک و بیابانی غربی استان در محدوده غرب شهرستان شوش و بستر خشک شده تالاب هورالعظیم در استان خوزستان می باشد. در گردوغبار متوالی بعدی (20/2/2018) فرسایش در بستر تالاب هورالعظیم و مناطق بیابانی در شمال سوسنگرد را می توان منبع اصلی ذرات گردوغبار قلمداد کرد. همچنین می توان مشاهده کرد که نواحی پراکنده در کشور عراق محدوده شهر بصره نیز در این گردوغبار موثر می باشند. در گردوغبار سوم در تاریخ 23/4/2018 بر اساس شاخص BADI دارای چندین هسته تراکمی می باشد و از نواحی بیابانی در کشور عربستان شروع و تا کشور کویت و نواحی جنوب غربی ایران و شرق عراق امتداد می یابد. همچنین در این پژوهش در محدوده های فضایی استخراج شده، نقاط برداشت ذرات گردوغبار به صورت دقیق تر با استفاده از تصاویر ماهواره ای Meteosat8 و سنتینل 3 تعیین شد که بارزترین منابع داخلی در منطقه جفیر و تالاب هورالعظیم و نواحی خشک و بیابانی شهرستان شوش در قسمت غربی استان خوزستان می باشند. همچنین در مورد منابع خارجی بیابان های کشور عربستان در مناطق غرب ریاض و شرق مدینه (الذکری، الرقایع و البجادیه) و مناطقی بین کربلا و نف در کشور عراق در شکل گیری توده گردوغبار نقش موثری دارند.

    کلیدواژگان: گردوغبار، الگوریتم های بهبود یافته دمای روشنایی گردوغبار، تصاویر ماهواره ای، خوزستان
  • مریم تورانی، مجتبی یمانی*، عطا عبدالهی کاکرودی صفحات 111-126

    نوسانات سطح دریای خزر نسبت به سایر دریاها و دریاچه ها سریع تر است. دریای خزر چندین دوره نوسانات شدید را در دهه های اخیر تجربه کرده است و این امر منجر به جابجایی خط ساحل در هر دوره از تغییرات تراز شده است. هدف این پژوهش بررسی تغییرات خط ساحلی دریای خزر در سواحل رودخانه تجن از سال 1334 تا 1395 است. داده های مورداستفاده در این پژوهش شامل عکس های هوایی و تصاویر گوگل ارث در سری های زمانی مختلف و همچنین آمار مربوط به دبی آب و رسوب رودخانه تجن است. برای انجام محاسبات موردنظر از نرم افزارArc GIS 10.3 و اکستنشن DSAD استفاده شد. محاسبات در 3 بازه زمانی که تراز دریا روند افزایشی یا کاهشی داشته است انجام شد و تغییرات خط ساحل در هر بازه زمانی به صورت مجزا بررسی گردید و نهایتا با داده های دبی آب و رسوب تجزیه وتحلیل صورت گرفت. نتایج نشان می دهد میزان نرخ نقطه نهایی (EPR) در بازه زمانی اول که کاهش تراز دریا رخ داده رقم1/76 است و در بازه زمانی دوم که افزایش تراز آب وجود دارد رقم نقطه نهایی11/90- است. در بازه زمانی سوم مجددا کاهش تراز آب رخ د اده و میزان نقطه نهایی 95/5 است. نتایج بیانگر آن است که در این بخش از سواحل دریای خزر وضعیت پیشروی و پس روی ساحل دقیقا منطبق با تغییرات تراز آب دریا است و پس از بررسی دبی آب و رسوب در هر بازه زمانی مشخص گردید که میزان دبی آب و رسوب نیز در تطابق کامل با فرسایش و رسوب گذاری ساحل است و درمجموع تمام عوامل در محل قرارگیری خط ساحل موثر هستند و تفکیک میزان اثرگذاری هر یک از عوامل بسیار دشوار است.

    کلیدواژگان: دریای خزر، تغییرات خط ساحلی، تغییرات تراز دریا، رودخانه تجن، بیلان رسوبی
  • رفعت شهماری اردجانی* صفحات 127-141

    شاخص های ژیومورفولوژیکی ابزار مناسبی را برای درک کارکرد و درجه پویایی این فرایندها معرفی می نمایند. در این مقاله از هشت شاخص ژیومورفولوژیکی سینوزیته جبهه کوهستان(Smf)، عدم تقارن حوضه زهکشی (AF)، نسبت پهنای کف دره به ارتفاع دره(VF)، شکل حوضه(Bs)، تقارن توپوگرافی عرضی(T)، منحنی هیپسومتری حوضه(Hc)، پیچ و خم رود (S) و گرادیان طولی رود (SL) برای تعیین وضعیت نو زمین ساختی حوضه  آبخیز کرگانرود تالش استفاده شده است. روش تحقیق بر پایه تحلیل فرم و فرآیند و داده های کتابخانه ای و نقشه های توپوگرافی، نقشه های زمین شناسی و تصاویر راداری و همچنین چند فقره بازدید میدانی استوار بوده است. نتایج تحقیق نشان می دهد حوضه آبخیز کرگانرود به عنوان یکی از حوضه های کوهستانی کشور در شمال غرب استان گیلان و شهر تالش واقع شده است. عبور گسل سراسری آستارا - تالش به طول حدود 400 کیلومتر در پایین دست دامنه های شرقی مشرف به جلگه گیلان، گسل نیور در نزدیکی خط الراس و نیز چین خوردگی ها، بیانگر فعال بودن نیوتکتونیک و نیز ظهور پدیده های مهم زمین ساختی در این منطقه می باشد. در راستای رسیدن به اهداف تحقیق از شاخص های هفت گانه ژیومورفولوژیکی حاکی از آن است که حوضه کرگانرود، از نظر نو زمین ساختی فعال، بیشترین شواهد فعال بودن تکتونیک در جنوب حوضه می باشد.

    کلیدواژگان: نوزمین ساخت، گیلان، کرگانرود، شاخص های ژئومورفولوژیکی
  • وحید صفریان زنگیر، بهروز سبحانی*، مجید رضائی بنفشه صفحات 143-165

    خشکسالی مختص مکان خاص نبوده و مناطق مختلف جهان از آن متاثر می باشد، یکی از این مناطق، شمال غرب ایران است که در چند سال اخیر از این پدیده رنج می برد. هدف پژوهش حاضر مدل سازی و تحلیل خشکسالی در شمال غرب ایران می باشد. برای این کار پارامترهای اقلیمی: بارش، دما، ساعات آفتابی، حداقل رطوبت نسبی و سرعت باد در بازه زمانی 32 ساله (2018- 1987) در 21 ایستگاه شمال غرب ایران مورد استفاده قرار گرفت. برای مدل سازی، شاخص فازی T.I.B.I ابتدا چهار شاخص (SET, SPI, SEB, MCZI) با استفاده منطق فازی در نرم افزار Matlab فازی سازی شدند، سپس شاخص ها با هم مقایسه شده و درنهایت از مدل تصمیم گیری چند متغیره Topsis، برای اولویت سنجی مناطق درگیر با خشکسالی استفاده شد. یافته های پژوهش نشان داد مدل T.I.B.I طبقات خشکسالی، چهار شاخص مذکور را به صورت دقیق در خود منعکس می کند. از بین 5 پارامتر اقلیمی مورد استفاده در این پژوهش، پارامتر دما در نوسان شدت خشکسالی بیش ترین تاثیر را داشت. شدت خشکسالی براساس مدل سازی صورت گرفته در مقیاس 12 ماهه بیش تر از 6 ماهه بود، طولانی ترین تداوم خشکسالی در منطقه مورد مطالعه مربوط به ایستگاه ارومیه در بازه 12 ماهه از ماه جولای سال 2003 تا ماه دسامبر سال 2004 به مدت 18 ماه رخ داده است. بیش ترین درصد رخداد خشکسالی در ایستگاه ارومیه در مقیاس 12 ماهه و کم ترین آن در ایستگاه سنندج در مقیاس 6 ماهه اتفاق افتاده است. براساس مدل سازی صورت گرفته، شاخص فازی T.I.B.I نسبت به شاخص فازی SPEI برتری نسبی را نشان داد.

    کلیدواژگان: منطق فازی، پایش خشکسالی، مقیاس 6 و 12 ماهه، T، I، B، I، شمال غرب
  • سکینه فجر، مریم ایلانلو* صفحات 167-184

    امروزه گسترش شهرها و روستاها سبب تسلط بیشتر انسان بر محیط زیست شده است، این امر سبب وقوع تغییرات محیطی بسیاری شده است. هدف از این پژوهش بررسی تغییر زمانی و فضایی چهار شهر ساحلی استان خوزستان (بندر امام خمینی (ره)، بندر ماهشهر، آبادان و خرمشهر) با به کارگیری سنجه های آمایش سرزمین طی دوره 20 ساله 2018-1998 برای تعیین دقیق الگوی مکانی -زمانی تغییرات می باشد. روش تحقیق حاضر کمی بوده و منطق حاکم بر آن استقرایی است. برای استخراج نقشه پوشش اراضی داده ها از طریق تصاویر ماهواره ای حاصل از ماهواره لندست متعلق به دوسال 2018 و 1998 که توسط سنجنده های OLI و MSS5 برداشت شده است، تصاویر در چهار طبقه اصلی مسکونی (شهر)، مناطق دارای پوشش گیاهی، زمین های مرطوب (رودخانه) و بایر دسته بندی شدند. پس از تهیه نقشه های پوشش سرزمین از نرم افزار Fragstats و TerrSat  جهت استخراج سنجه های سیمای سرزمین در دو سطح کلاس و سیما استفاده شد. نتایج تحقیق نشان می دهد که شهر آبادان در سیمای سرزمین دارای الگوی Aggregation, Attrition و Dissection در شهر بندر امام خمینی (ره) Aggregation, Attrition خرمشهر دارای Creation, Attrition و Dissection و در بندر ماهشهر سه شاخص Creation, Attrition و Aggregation مشاهده می شود. همچنین در هر چهار شهر مورد بر مساحت مناطق مسکونی در بازه زمانی افزوده شده است.

    کلیدواژگان: تغییرات زمانی- فضایی، سنجه های سیمای سرزمین، نرم افزار Fragstats، شهرهای ساحلی، کاربری اراضی
  • پیمان یاریان، محمدرضا کرمی* صفحات 185-203

    زلزله یک تهدید جدی برای جوامع بشری محسوب می شود. علاوه بر شرایط زمین شناسی و نوع گسل، عوامل مختلف محیطی، کالبدی و اجتماعی در تشدید میزان آسیب پذیری ناشی از آن تاثیر خواهند گذاشت. کشور ایران ازجمله زلزله خیزترین کشورهای دنیا به حساب می آید و تاکنون تلفات زیاد مالی و جانی متوجه بسیاری از استان ها و شهرهای آن شده است. شهر سنندج نیز به عنوان مرکز استان کردستان در غرب کشور به دلیل وجود گسل های مریوان - سیرجان، زاگرس، تراکم بالای جمعیت و... (عوامل طبیعی و انسانی) دارای شرایط نامساعدی است. به همین دلیل ارزیابی خطر ازجمله برنامه های مهم در مدیریت پیش از بحران به حساب می آید. در فرایند ارزیابی خطر، انتخاب فاکتورها و معیارهایی که بیشترین میزان تاثیر در تشدید یا کاهش آسیب رادارند امری مهم و تخصصی محسوب می شود. هدف این پژوهش ارزیابی آسیب پذیری شهر سنندج در برابر زلزله است که با انتخاب 13 لایه از معیارهای طبیعی، کالبدی و اجتماعی و انتخاب اوزان لایه ها برمبنای پژوهش های و منابع سابق با استفاده از نرم افزارهای ArcGIS و IDRISI اقدام به ارزیابی نقشه خطر از طریق مدل FAHP گردید. با توجه به نتایج حاصل، مدل ترکیبی Fuzzy-AHP به عنوان مدل بهینه شناخته شد؛ و خروجی به صورت نقشه و درصد آسیب پذیری هر طیف استخراج گردید. نتایج حاصل حاکی از آسیب پذیری بالا در مناطق 1 و 2 شهر سنندج ازجمله محلات قطارچیان، گلشن، بعثت، تازه آباد، جورآباد، تپه شیخ صادق و عباس آباد و در منطقه 3 کلکه جار، مبارک آباد، ویلاشهر و شهرک بهاران است که آسیب پذیری در مناطق جنوبی شهر ناشی از شرایط محیطی و در مناطق شمالی بیشتر تحت تاثیر ویژگی های کالبدی و اجتماعی است.

    کلیدواژگان: عدم قطعیت، ارزیابی خطر زلزله، منطق فازی- ای اچ پی (Fuzzy-AHP)، مدل سازی، شهر سنندج
  • فاطمه فیضی کوشکی، مرتضی اکبری*، هادی معماریان، محمود اعظمی راد صفحات 205-225

    بیابان زایی از مهم ترین عوامل تخریب سرزمین در نقاط مختلف جهان به ویژه مناطق خشک به شمار می آید و شناخت عوامل اصلی این پدیده می تواند در مدیریت صحیح و مناسب اراضی بسیار موثر باشد. لذا این تحقیق باهدف شناسایی و رتبه بندی شاخص های موثر خطر بیابان زایی در مناطق خشک شمال شرق ایران-استان خراسان رضوی و بر اساس روش دلفی، انجام شد. در این پژوهش ابتدا، بر اساس توزیع چندمرحله ای پرسش نامه (راند) در بین جامعه آماری که شامل؛ مدیران اجرایی، کارشناسان و متخصصان حوزه منابع طبیعی است، مهم ترین عوامل تاثیرگذار در گسترش خطر بیابان زایی استان خراسان رضوی شناسایی گردید. روایی و پایایی پرسش نامه ها به ترتیب طبق نظر جامعه خبره و همچنین با استفاده از ضریب آلفای کرونباخ محاسبه شد. تجزیه وتحلیل آماری نتایج حاصل از پرسشنامه ها و رتبه بندی شاخص ها در محیط نرم افزاری  Matlabو SPSS انجام گردید. سپس با بررسی روایی پرسشنامه ها 30 پرسش اصلی انتخاب شد و نتایج پایایی نیز بیانگر ضریب آلفای کرونباخ معادل 0/823 می باشد که اعتبار و پایایی قابل قبول پرسش نامه را تایید نمود. نتایج حاصل از راند اول پرسش نامه ها نشان داد که معیارهایی همچون معیار اقلیم، آب، فعالیت های انسانی، معیار اجتماعی-اقتصادی، پوشش گیاهی، فعالیت های کشاورزی، خاک و زمین شناسی و فرسایش  به ترتیب از مهم ترین عوامل توسعه بیابان زایی بوده اند. نتایج ارزیابی پرسشنامه ها در راند دوم، طبق روش دلفی و آزمون آماری فریدمن نیز نشان داد فعالیت های انسانی با شاخص بهره برداری بی رویه از سفره های آب زیرزمینی، معیار اقلیم با شاخص خشک سالی های مکرر، معیار آب با شاخص برداشت بیش ازحد از منابع آب زیرزمینی، معیار اجتماعی-اقتصادی با شاخص بهره برداری شدید از جنگل ها و مراتع، معیار پوشش گیاهی با بهره برداری بی رویه از پوشش گیاهی، معیار کشاورزی با شاخص الگوی غلط کشت و عدم رعایت تناوب زراعی، معیار خاک و زمین شناسی با شاخص فرسایش پذیری خاک در برابر عوامل فرساینده از مهم ترین معیارها و شاخص های موثر در گسترش خطر بیابان زایی استان خراسان رضوی در طی 30 سال گذشته بوده است.

    کلیدواژگان: شدت بیابان زایی، تخریب سرزمین، شاخص، تجزیه وتحلیل آماری، پرسش نامه
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  • Mansor Parvin *, Ramin Hatamifard Pages 1-18
    Introduction

    Karst is the result of the dissolution (physical and chemical) in carbonate (limestone and dolomite) and evaporate rocks. Karst developing is affected by climatological and geological factors. In the other words, Karst landscapes and Karst aquifers are formed by the dissolution of carbonate rocks by water rich in carbon dioxide waters. Various processes and factors such as topography, lithology, tectonic, geomorphological and hydrological processes and climatic factors have an important role in the evolution of Karst. Karst aquifers are a precious resource because they provide drinking water for about 25% of the world’s population. Karst Aquifers are typically very productive due to their ability to convey water through a network of interconnected conduits. The analysis of hydrograph recession curves is an often-used method in hydrological studies, providing the interpretation of the characteristics and flow attributes of the aquifer.
    The study of hydrodynamic and hydro-chemical properties of springs can be an indicative of the Karst development in Karst media. Social and economic life of cities such as Nourabad, Alashtar, and numerous rural societies is connected to the Gareen Mountains springs. Also the origin of Kashkan and Seymareh rivers is located in the Gareen Mountains. This shows the importance and necessity of studying Karstic springs in this area. The aim of this study is to investigate and evaluate the effect of drought occurrence and Karst geomorphology on the quantitative and qualitative features of Green Antarctic Springs in Lorestan Province.

    Material and Methods
    2.1. Case Study

    The Gareen Mountains in the Zagros Mountain Range is located in the active deforming Zagros fold-thrust belt and Sanandaj-Sirjan zones. The Gareen Mountains is located in the west of Iran. The most important mountains in the area are Velash, Chehel-nabaleghan, Seh-kozan, Higdah-yal and Mishparvar. Alashtar and Nourabad Karst Aquifers are located in the north of Lorestan Province. There are several thrust faults with northwest–southeast strike such as Gareen-Gamasiab and Gareen-Kahman Faults. Nourabad Aquifer is composed mainly by gray limestone rocks, embedded marl limestone, recrystallized limestone and pyroclastic rocks. One of the most important features of the structural geology of the Alashtar Aquifer is the abundance of the sedimentary rocks and scarcity of igneous rocks in this area. Doline, Sinkhole, Cave, Ponor, and several types of Karrens and Karstic Window are the main Karstic features in the area.

    2.2.Method

    The Standardized Precipitation Index (SPI) is the most commonly used indicator worldwide for detecting and characterizing meteorological droughts. The SPI indicator, which was developed by McKee et al. (1993) and described in detail by Edwards and McKee (1997), measures precipitation anomalies at a given location, based on a comparison of observed total precipitation amounts for an accumulation period of interest (e.g. 1, 3, 12, 48 months) with the long-term historic rainfall record for that period. The historic record is fitted to a probability distribution (the “gamma” distribution), which is then transformed into a normal distribution such that the mean SPI value for that location and period is zero due to increasingly severe rainfall deficits. The Standard Precipitation Index (SPI) is calculated using the following equation: 
    SPI=Pi -) P/σ)                                              (Eq.1)
    To achieve the goals of this research, 5 main draining springs were chosen in the Gareen Mountains, including Amir, Ahangaran, Chenareh, Laghary and Teymour Springs. After the survey of geomorphological, climatic, hydrodynamic, hydro chemical, physiographic properties and several field studies, the karstification degree in each aquifer was determined by using the hydrodynamic and hydro chemical properties. 
    In this study we used a mathematical formula to describe the falling limb of hydrographs and the base flow proposed by Maillet (1905) (Eq.2):                                                          (Eq.2)
    The dimensionless parameter α in Eq.1 is the coefficient of discharge (or recession coefficient) which depends on the aquifer’s transmissivity and specific yield, Qt is discharge in” t” time (m3/s), Q0 is beginning of discharge in t0, t is time elapsed between Qt, and Q0, e (mathematical constant) and α is the recession coefficient.
    In addition, water samples in Karst springs in a period of 15 years (2001-2015) were used for hydro-chemical analysis. Hydro chemical analysis including total anions (HCO3, SO4 and Cl), Cations (Ca, Mg, Na, and K), Electrical conductivity (EC), Ca/Mg, total dissolved solids (TDS) and total hardness (TH) were used to determine the origin of the Karstic spring's water.

    Results and Discussion

    The calculation of α coefficient is one of the most important parameters in hydrogeological spring’s studies. Higher α coefficient represents springs much influenced by precipitation. This situation reflects the high porosity and high Karst development in the region. Conversely, the low α coefficient indicates the less karstification. Along with other factors, higher volume of dynamic storage in the basin of a spring indicates the high degree of karstification. In other words, less karst development leads to slow movement of water in the spring basin. This factor will increase the volume of dynamic storage. For identifying the karstification degree in the territory of the Gareen Mountains, we use the recession curve of spring's hydrographs and Malik and Vojtkova method.

    Conclusion

    According to the Hydrodynamic Study, Amir, and Chenareh springs have the karstification degree 2.7 and 2.5, respectively. Furthermore, the groundwater flow sub-regimes type is the combination of two or more sub-regimes with merely laminar flow characterized by different discharge. Ahangaran Spring has the karstification degree 4.3 and the discharge hydrogram is composed of a sub-regime with turbulent flow and a sub-regime with laminar flow. Laghari and Teymour springs have the karstification degree 5.5 and complex discharge regime, a combination of one sub-regime with turbulent flow and two sub-regimes with laminar groundwater flow. In other words, based on hydrodynamic results, Laghari and Teymour springs have the highest karstification degree in the Gareen Mountains. The results show that Amir and spring have the highest and Ahangaran and Laghari springs have the lowest volume of dynamic storage. According to the SPI method of years 84-88, the highest and most severe damage occurred within the scope of the study. Thus, during these years the springs of the study have dropped dramatically. The results of the comparison of SPI with discharge show that hydrological drought occurred due to the development of karst with different time delay has affected the spring’s aquifer. Thus, the fluctuations of precipitation with a shorter time lag appear in the aquifer of Ahangaran, Teymour and Laghari springs. However, in the aquifer of the Amir and Chenareh springs, due to the low karstification degree, the drought has been delayed for about 24 months .According to hydro chemical results, the highest and lowest total dissolved solids (TDS) values were found in the Chenareh and Ahangaran springs, respectively. Also, Ahangaran and Teymour springs have the highest and lowest t, otal hardness (TH) values respectively. Reducing precipitation and drainage have also led to an increase in TDS and TH in these springs.

    Keywords: Geomorphology, the Gareen anticline, Karst, Drought, SPI
  • Maryam Bayati Khatibi*, Behrouz Sari Sarraf Pages 19-39
    Introduction

    Each change in environment conditions or climatic conditions is a cause of wind and water erosion process changing and also for environmental hazard events. Changing at physical and chemical soils property occurs due to a change in the erosion process. All this changing is reflected on grain type of sediments and form of deposits stratum. With due attention to historical documents, environment hazards have occurred repeatedly in the past time, including droughts, floods, earthquakes and also high snow precipitation in Tabriz Plain. Geo-process and biome is affected within these events in the plain during of past time. The Plain of Tabriz was highly sensitive to human changes and climate change. With the change in the climate of the northern region from 3000 to 4500 years ago people migrated to the plain of Tabriz and changed the characteristics of the plain by cultivation or other activities. These activities and occurrence of floods and droughts dramatically changed the environment and evidence of these changes remained in the deposits.

    Material and Methods

    In this paper paleo-pedological data are used for the dating of Tabriz plain deposits. The chemical and physical properties of the deposits have been studied and tested. Various samples of soil have been collected and examined in the laboratory. The PH, SO4, CL, content of the collected samples was measured and determined. Specimen deposits were used to collect specimens at depths below 3 m that exhibited different characteristics. Geomorphological methods are other methods to understand the past story of plain that used. SED methods are geomorphological methods used in this study.

    Results and Discussion

    Changes in the amount of SO4 deposits indicate major environmental changes in the Tabriz plain. When environmental SO4 changes were less than 300 ppm, environmental conditions changed. The environment would be more humid. When SO4 reaches 2,500 or more, the environment becomes drier. The results of the studies show that the amount of SO4 at lower depths and in the lower deposits is high. This indicates that Tabriz plain has undergone many changes and the environmental conditions of the whole have changed. These findings suggest that the drought was severe. In 10-15 depth of underground amount of salt is very high. In study area rate of Cl is vary from 3 to 12 m/a/l. The rate of TDS is low. The study of PH at environment changing understanding is very important. In study area PH from 8.6 to 8.3 is vary. Lowland have low PH. Examination of aggregate deposition reveals the soil texture is clay–silt and clay-loam. Wildfires and excessive use of land are the cause of the fine texture of soils. At a depth of 20 meters 50% of the volume of deposits is composed of clay. In some parts of the old clay plain more than 80%. The large amount of clay in the deposits indicates significant environmental changes in the past. The results show that the carbon content in the upper layers is high. When grazing livestock is growing, either drainage is poor or plants plant density is low, the amount of carbon is increased. High fluctuations in chloride levels mean significant changes in environmental conditions. The high chloride concentration indicates the occurrence of environmental drought. The samples taken show an increase in the chloride content in the various sections of plain. 8000 ppm chloride in Tabriz plain indicates that significant changes have occurred in this plain at Pleistocene period. The fine-grained material has been deposited at times where the ambient energy was at its lowest level. Chloride formation or chloride stability near the surface of the sediments is more related to the colder climate.

    Conclusion

    Examination of different samples of deposits reveals past environmental conditions. In the past, floods and droughts have occurred in larger and more severe dimensions. Occasionally, the climate becomes drier and accumulates more salt in the deposits. The sandy texture of the deposits indicates the intensity of the winds in the Tabriz plain. Sandy materials at around plain and exposed soils ware important sources of aeolian material into Tabriz plain. The sand in mountain areas ware mostly of volcanic origin, either deposited as volcanic ash or reworked by physical weathering of volcanic rocks by glaciers, glacial rivers and other physical factors. Higher areas had drier conditions and their soil was mostly Claysols. Maximum cumulative thickness of sillt soil and salt deposits in the soil profiles was measured as 20 cm whereas average thickness was 10 cm. The thickness of clay layers varies in different parts of Tabriz plain.

    Keywords: Environment Hazard, Palepedologic, Paleoclima, Tabriz Plain
  • Meysam Yari, Somayeh Soltani-Gerdefaramarzi*, Mohsen Ghasemi Pages 41-58
    Introduction

    One of the factors affecting the surface runoff characteristics and the fluctuations of groundwater in the watersheds is the land use change at different levels of the basins. Land use change can also be a conversion from one user to another, or, in other words, changes in the composition and pattern of land use in a region, or the modification of a particular type, is land use change (Jakeman et al., 2005). Incorrect land use changes will disrupt the water cycle from natural equilibrium, which will result in damage caused by devastating floods, including economic losses, loss of life, waste of water, and consequently the loss of water resources. Land use changes also affect surface and subsurface flow changes (Palamuleni et al., 2011). On the other hand, groundwater, like other natural resources (both quantitatively and qualitatively) is subjected to the threat of human activities. Underground water drainage and depletion of groundwater aquifer and its consequences including increased water harvesting costs, land subsidence, and water quality has declined across regions of the world. In recent years, several studies have been done on land use change. For example Zou et al. (2016) detected hydrological changes using statistical tests, SWAT, and land use maps. The results show significant decreasing trends in both annual runoff and sediment loads, whereas slightly decreasing and significantly increasing trends are detected for annual precipitation and air temperature, respectively. Akter et al. (2018) investigated the hydrological behavior due to the urbanization under current and future climate scenarios of high summer and high winter rainfall for 20 sub-catchments of the Schijn River, in Belgium. Results revealed that peak flow for urban runoff and the total peak flow (i.e. rural and urban runoff) were significantly higher (i.e. ranges from 200% to 500%) than the existing rainfall-runoff model (PDM) flows because of faster and more peaked urban runoff responses. Lee and Brody (2018) examined the impact of land use on flood losses in Seoul, Korea. Results indicate that urban built-up land with higher impervious surfaces and agricultural land may cause more flood damage than other land uses analyzed in the study. However, a high density development of compact design can decrease flood loss. These results indicate the importance of resilient land use planning in urban areas. Jodar-Abellan et al., (2019) investigated the impact of land use changes on flash flood prediction using a sub-daily SWAT model in five Mediterranean ungauged watersheds. The results showed that with increasing flow rate peaks and decreasing concentration time and high urban development along the Spanish coastline in the studied basin, the curve number increased and the discharge rate exceed 900 m3/s. The aim of the current research is to study the effect of different land uses and its changes during the years 1371, 1381, and 1391 on surface run off, flood, and groundwater fluctuations in a part of Ghareh Su, Ardabil watershed.

    Materials and Methods

    The study area in this study is part of Ghareh Souh basin in Ardebil province with an area of 2162.62 square kilometers in the geographical area of 48º 27ʹ 36" and 49º 12ʹ 06" east longitude 37º 47ʹ 20" and 38º 37ʹ 25" in the north latitude. The minimum and maximum altitudes of the watershed are 1280 and 3829 meters above sea level respectively, and the average slope is 11.57 percent. Land use in this area often includes forest, water farming, wasteland land, rangeland, dry farming, and urban land uses. Among the types of land uses in the studied basin, the use of dry farming has the highest level of the basin. In this research, satellite images needed for the years studied (1371, 1381 and 1391) were prepared from the site of the US Geological survey. After providing satellite imagery for the study area, ENVI software was used during different stages of image processing. For this purpose, maximum likelihood classifier was used to study vegetation changes. Before analyzing satellite data, it is necessary to make corrections on raw images. In remote sensing, raw data errors are sensor errors and atmospheric effects. To correct the error, the method of atmospheric correction and systematic geometric correction are used. At first, the maps of land use and curve number in the mentioned years was gathered and the area of each of units was extracted. In continue, the process of land use changes in the cases of study period and its effect on changing the curve number and height of runoff and then stimulation of flood by the model of HEC-HMS and drawing of the hydrograph was done. In the end, the effect of land use changes on groundwater level was studied. To calculate runoff from annual precipitation, the average annual precipitation of 14 rain-gauge stations was used in the part of the Ghareh Souz basin.

    Results and Discussion

    In this study, permeability was obtained using a soil map of the region that included soil texture characteristics. Then, due to soil permeability, a map of soil hydrological groups (A, B, C and D) was extracted. It is observed that the hydrological group C has the largest area, which is equal to 49.82% of the basin, and the hydrological group B also includes 72.74% of the basin area. Therefore, due to the fact that the hydrological group C has the largest area in the basin area, the studied basin is more capable of runoff production. Regarding the results, it can be seen that the studied area is more moderate and relatively low permeability classes in terms of permeability. The results showed that total losses in 1371 was 69.28 mm, which in 1381 was 66.95 mm and in 1391 it decreased to 64.42 mm. The amount of runoff was reduced which was 263.4 mm in 1371, but in the year 1381 the amount of runoff increased to 294.785 mm which in 1391 it increased to 297.07 mm . The increase in runoff in the studied basin can be due to an increase in the number of curves. The results showed that during the case of study period, forest areas, water farming, and wasteland uses were decreased to 2.54%, 16.69%, and 1.19%, respectively and the area of the rangeland, dry farming, and urban land uses increased to 5.74%, 12.39%, 2.29%, respectively. This changes have caused the increase of curve number from 78.57 to 79.77 in the year 1371 and 1391, respectively and following the decrease of total losses from 69.28 millimeters in the year 1371 to 64.42 millimeters in the year 1391. Also, run off height has increased from 263.4 millimeters in the year 1371 to 297.07mm in the year 1391 (11.33%). Considering the curve number and flood stimulation, the achieved results showed that peak discharge and flood volume have increased to 9.49% and 6.67%, respectively. In the end, these changes have led to a decrease of groundwater level to 6.14 meters (39.06%) during the studied period.

    Conclusion

    Due to the increased utilization of urban land as well as the increasing dry farming and underground water withdrawals, by decreasing the permeability of the basin soil, the amount of flood and runoff has increased and eventually we face a drop in groundwater. Calculation of correlation coefficient between different land uses and curve number, runoff height, flood volume, and groundwater level showed that these variables have direct relation with rangeland, dry farming, and urban land uses while they have inverse relationship with forest, water farming and wasteland.

    Keywords: Land use, flood, groundwater, correlation, Ghareh Su, Ardabil provience
  • Mohammad Hossein Rezaei Moghaddam*, Mir Asadollah Hejazi, Abdollah Behbody Pages 59-75
    Introduction

    Conservation of soil and water resources is one of the most important principles of proper management of catchments. Therefore, erosion and changes in land use concerns make the importance of predicting the effects of these actions on soil water resources even more important. Therefore, it is necessary to model and evaluate their results. In order to better manage the water balance of the catchment areas, it is essential that the modeling of hydrological phenomena in the catchment area can be an optimal solution for them because of the time it consumes and the costly measurement of water balance components (Zarehkarizi & Talbi, 2016). Therefore, accurate knowledge of the hydrologic behavior of catchment areas can help to better simulate this environment in order to control the main components of the water table (Mojenazadeh, Gahraman, & Davari, 2016). On the other hand, the limitation of measurement methods in hydrology and the need for a method for generalizing the statistics to untapped basins or places that cannot be measured, as well as the simulation of future hydrological changes are among the main reasons for hydrological simulation (Beven, 2001). Many models have been proposed for describing and forecasting the hydrology of the rivers that are very different from the point of view of the time scale and spatial scale (Setegn, Dargahi, Srinivasan, & Melesse, 2010). One of these models is the recent SWAT hydrological model. This model is a semi-distributive model designed to simulate the hydrology of the catchment area on a daily scale. In order to investigate the effect of different management strategies on flow, sediment, nutrients and chemical shale in different watersheds, Land is developed (Arnold et al., 1998).

    Materials and Methods

    The Lanbarn watershed is located on the eastern side of the Aharchay River. The area of this sub-basin is 20118 hectares and is the main axis of the Aharchi River. This basin is located in Sina subdivision from the central part of Varzaqan City of Eastern Azarbaijan Province. The SWAT model was used to study runoff in this basin. The SWAT is an example of basic physics models that solves the fundamental physics equations to simulate the processes of the catchment system. This model is semi-distributed and temporally connected in terms of spatial scale. The SWAT model simulation can be divided into two main parts: terrestrial and aqueous phase. Terrestrial phase is related to land surface processes and water, sediment and chemical elements to the main waterways of each sub basin. The aqueous phase simulates the processes of waterways and canals involving the movement of water, sediment, and chemicals.  The smallest unit in this model is the HRU Hydraulic Response Unit, which is derived from the combination of slope, soil and land use maps. Soil water, surface runoff, sediment and chemicals are first calculated for each HRU and then for each sub-basin and finally for the entire catchment. The data used in this study include topographic map, land use, soil, precipitation, minimum and maximum temperature, wind speed, solar radiation and daily relative humidity of synoptic stations of Ahar, evapotranspiration of Varzgan and Rain gauges of Eilagh and Dubai Cassine Station. The study area was divided into 17 sub-basins and 469 hydrological units. From 2000 to 2003, the model was warmed up 10 years for calibration and 4 years for validation.

    Results and Discussion

    In order to determine the degree of sensitivity of the flow parameters in the SWAT model, two methods of SUFI-2 and GLUE sensitivity tests for the 22 selected parameters were performed. Of the 15 critical parameters of the SWAT model, the density of the soil mass, the soil hydraulic conductivity in the saturation state, the coefficient of evaporation of groundwater, the constant flow rate from the canal, the snowfall temperature, and the snow melting temperature are more sensitive. In terms of 15 sensitive parameters, the swat model is more sensitive to soil mass density factors, saturated hydraulic conductivity, ground water evaporation coefficient, canal discharge constant, snowfall temperature, snow melting temperature. All model assessment criteria in runoff simulation are allowed. But the comparison of the two methods shows that the SUFI-2 method has a better performance than GLUE in this basin. The comparison of graphs, real discharge and the monthly simulated values shows that SWAT model underestimates runoff underestimates. Most streams that the model could not simulate were in late winter and spring. One of the weaknesses of the model in estimating the maximum runoff is the use of the SCS model in the calculation of runoff, which does not simulate the runoff from snowmelt appropriately.   

    Conclusion

    The results of the application of two methods of SUFI-2 and GLUE in the Lanbran watershed were investigated. Based on the evaluation criteria of the SUFI-2 method, both calibration and validation stages have good results as compared with the GLUE method in this basin. Also, both methods could not predict peaks because they predicted both methods in Dubai sky-highs to be less real than actual Dubai. Although it is easier to use the GLUE method than the SUFI-2 method, the number of simulations is higher for the solution in the GLUE method, Therefore, according to the results, it can be concluded that the SUFI-2 method with low simulation numbers is better than GLUE in this basin.

    Keywords: Lanbaran Chay, SUFI-2 Model, calibration, SWAT Model, Uncertainty
  • Abas Mamagane, Mohsen Zare Ahmadabad*, Mehran Maghsoudi Pages 77-95
    Introduction

    Our country lies in the arid and desert belt of the world and is two-thirds of its size in the realm of dry land. Works such as the drying up of inland lakes, sandstorms, dust, and the intensification of wind erosion have prevented the rate of desertification in recent years in the country (Shiravi & Sepehr et al., 2016). The area of ​​arid and ultra-arid regions is 472566 and 573884 km2, respectively, which is approximately 631.5 arid and semi-arid territories based on the modified Damarton system. In this system, the areas with drought index between 0-5 and 10-15 are considered as arid and ultrasound respectively. The amount of erosion and the volume of material transport in arid regions depend on the wind speed, direction and frequency characteristics, and on the ground, topography, and sedimentary features. Understanding the geomorphologic features of the toll that develops in the morphoclimatic environments of arid regions can inform us of such environments and aware the human beings towards actions that may alter ecosystems and natural habitats. The geomorphologic features of arid lands especially sand dunes are the result of specific dynamics and variability in these areas (Xin-Rong Li et al … 2010).
    Investigating and studying the related research background, it was found that most of the geomorphologic classifications and analysis of arid lands were done using the most important factors affecting the geomorphologic, geomorphometric parameters, and the prevailing winds. The present research was conducted to identify and investigate several sections through dominant wind and mineralogical analysis in the hilltop sand dunes located on the western side of the Sufian city, which today is experiencing the development of downstream industries.

    Materials and Methods

    One of the important factors which is necessary for the formation of wind dunes is the source and the origin of the sand. It is not formed without the elements in the size and size of the dune sand. Therefore, in areas where there is wind erosion and the source of sand harvesting, they are heterogeneous. Pie and Tsevar (1990) find that the amount of sand supply is dependent on the type of rocks exposed in the area, the speed, weathering conditions, the erosion, and the efficiency of other sediment transport factors in separating the sand particles from the larger particles. According to Smith (1982), running water often plays a key role in the sorting and concentration of weather-induced crop transfer products. In order to provide the source and the origin of sand, conditions, and factors are known as morphogenesis and morph dynamic systems.

    Results and Discussion
    Morphoscopy of sand dune elements


    For morphoscopy examination of sand in hill tribe, 5 specimens were selected systematically according to their dispersion while the microscopic examination was performed on them. In this study, the grains were studied from two aspects, one being the surface condition of the grains having matte, aura, luminous, physical, and chemical degradation modes, and the other in terms of abrasion; thus, the grains are more exposed to water and wind. The more it is worn, the more rounded it is and the distance traveled can be determined in addition to the shipment.

    Wind situation based on synoptic stations

    The purpose of this study is to study the mineralogy of the origin and to analyze sand dunes cross section in Qom Sufi hills, firstly, based on daily wind statistics of Shabestar and Tabriz synoptic stations, which is the nearest synoptic study site. Using Land Rose software, wind direction prediction (annual and monthly) was done. Based on the theoretical basis that wind flows from a high-pressure cell to a low-pressure cell, the temperature gradients have an effect on the temperature between the two currents.
    Considering the direction of the winds in the region, the study has been attempted to identify the topography of the wind erosion forms, their location, and how they affect the direction of the region's winds. The wind data from the Tabriz Synoptic Station and Shabestar West between 2012 and 2017 were used to investigate the wind situation in the region. Accordingly, high winds at the Shabestar station, northwest-northeast and at Tabriz station, east-northeast with high frequency and speed. Of course, there were also winds with less abundance in the north, northwest, south, and southeast.

    The early origin of the hill folk dunes

    The wind dunes of the Northeast Highlands (Moreau), the Northwest Highlands (Misho), and the North Sufian Highlands can be considered as the primary from their original location sources after the impact of morphogenesis and degradation of the rocks due forming these mountains. Directly transported by wind and deposited in the local wind dunes it accumulates in the form of sand dunes. But, in the Qom hill Sufian can such a sand be found to have the properties to move and precipitate directly after being separated from the base stone by wind. Morphoscopy on the sands of the region also confirms this. Therefore, the material produced in these mountains by morphogenic processes is transported by transport agents, especially current waters and is accumulated in lower areas after decelerating; thereby, providing a secondary source for the dunes are examined.

    Secondary origin of the hill folk wind dunes

    Secondary origin is that the dispersed material is transported in elevated areas and at its initial location under the influence of morphogenic factors, especially water, and is accumulated in sediments, alluvial fans, rivers, and pits (Jian Hua XIAO et al. 2015), and then as these discrete elements dry up, the wind moves them and accumulates as wind dunes. As the dunes expand and the southwest wind prevails over other winds, the secondary origin of these dunes will be mostly in the west and southwest of the region. This does not mean, of course, that only sand is transported to the area.  Because of the prevailing winds and their predominance at certain times of the year, they can move sand from other areas, especially east and northeast, due to the dominance of the east and northeast winds in summer according to the charts. Therefore, the secondary origin of wind dunes in the region can be divided into: 1) Old rivers, streams and riverbeds   2) Impact cones   3) Rubble cones   4) Lakes   5) Lakes terraces, and 6) Dunes.

    Conclusion

    Like most sand dunes in Qom, the sand dunes have a gentle slope to the direction and side to the wind and a steep slope to the back. On the back side of the wind, there are protrusions and recesses. The protrusions are made by connecting the arms to each other and have a lower height and slope while indentations are longer and have a higher slope. The origin of the winds in the region is mainly due to the predominantly sandy soils as well as the occurrence of fine sediments at the end of the area's fan cone and plate floodplain, which may not account for much of the surface area. And the end of by cones feeders that bring out the sedimentary are provided. In fact, the rivers of the area, after exiting the mountains, developed on the plainand and aware of there are processes affecting the development and evolution of the sandy surfaces of their have surrounding land. The results show that wind erosion is more frequent wherever plate floods are wider. As a result, the main source of sand supply is the sediment of the old rivers and the barren lands without its hard surface cover. In order to orient the source regions, the status and direction of the winds of the area were analyzed using the Globad diagrams and field data were selected from five sections systematically. High energy verifications indicate that the main contributors to sand supply and dominant winds by transport of fine sediments and rocks (carbonate and volcanic) are bedrock of old rivers and barren lands without surface cover wherever floods occur. The wider the plate, the higher the wind erosion in favor of dune development.

    Keywords: Sand Dunes, Geomorphology, Cross Sectional Analysis, Qom Hill Sufian, XRF, XRD Tests
  • Nemat Malamiri, Alireza Rashki*, Seyed Reza Hosseinzadeh, Mahnaz Gahadi Toroqh Pages 97-110
    Introduction

    A dust storm is a common environmental hazards in the world, especially in arid and semiarid regions of the world. The incidence of dust has been higher in recent decades in Iran, especially in Khuzestan Province, which has become an environmental crisis in recent years. The occurrence of dust in Khuzestan Province is due to natural conditions such as successive droughts and loss of moisture sources as well as human factors such as drying of the water zones and the reduction of river water discharge due to the dam. Various methods have been developed to identify dust sources, most notably the use of remote sensing techniques. Accordingly, for the detection of dust storms, a number of dust indices have been developed based on MODIS images, the most effective of which is the use of the BADI. Therefore, in this study, three consecutive dusts in winter and spring of 2018 in Khuzestan Province were studied through the BADI.

    Study area

    The study area includes the lands west of Khuzestan Province between north latitudes of 32°8'.62" to 30°57'.26" and east longitudes of 47°43'.21" to 48°32'.29". In terms of political divisions, this area has two cities, shush city in the north, and the Dasht Azadegan is in the south, which has a common border with Iraq. Karkheh River is the most important river in the area which is flowing through Khuzestan plain to Hoor Al-Azim Wetland.

    Material and Methods

    In this study, the BADI index was used for desert dust   detection. First, to use this index, Modis 1B satellite images were obtained from the NOAA Archive (https:// ladsweb. modaps. eosdis.nasa.gov/search/).
    Subsequently, geometric corrections were made to them and using calibrated images, the brightness temperatures were calculated in bands 20, 31 and 32 of Modis images. Also, Meteosat 8 satellite images were used to specify the dust source regions. In addition, Sentinel 3 satellite images were overlaid with Google Earth satellite images to determine the exact locations of dust particles.

    Results and Discussion
    BADI Algorithm

    According to BADI index extraction, in the dust of 20/1/2018 it was observed that the main source of dust is in the western part of Shush City and the dry bed of Huralazim wetland in Khuzestan Province. These conditions cause severe dusting due to local topography (flat area and non-vegetation lands). In addition, conditions for dust formation have been provided due to development plans and the elimination of local morphology as well as the loss of soil moisture (land drainage) in the south and west of Khuzestan Province. In the next dust storm that occurred about a month later in the winter (20/2/2018), the results show that erosion in the Hoor Al-Azim Wetland and the desert areas in the north of Susangerd can be considered as the main source of dust particles. Therefore, the amount of soil erosion after dust based on field operations and the measurement of fixed rod height indicates approximately one centimeter of height difference between the two successive dusts. In the third dust on 23/4/2018, a very large dust with high mass, several density cores were seen which would begin in the desert regions of Saudi Arabia and extend to Kuwait and Southwestern Iran and also Eastern Iraq.

    Determining the sources of dust

    Meteosat 8 satellite images were used at different times of the day to identify the high dust areas. The spatial area of dust particle loading was determined from the beginning to the time of the dust mass expansion. In the dust on 20/1/2018, first the inner sources of the Dust were activated due to the cyclonic motion of the air mass. In the dust of 19/2/2018, it can be stated that the soil erosion of the Hoor Al-Azim bed and the surrounding areas such as Gofer and arid lands of southern Bostan are the main cause of this phenomenon. In the next dust on 23/4/2018 the main sources of dust are the deserts of Saudi Arabia (Kuwait and Saudi Arabia) and the deserts of Northern Najaf and Southern Karbala in Iraq. Then, Sentinel 3 satellite images were used to determine more precisely the dust loading points in the study areas. Therefore, the results illustrated had a significant role in increasing the volume and concentration of dust in winter the eastern areas of Hoor Al-Azim (Gofer and Southwest Bostan) and the western deserts of Shush. Also, based on the detection of dust dumping sites, the results indicated that three areas in the west of Riyadh and east of Medina (Al-Dhakari, Al-Raqqa and Al-Bujadiyah) play an important role in the formation of the dust mass.

    Conclusion

    The purpose of this study was to monitor the dust and extract dust sources of West Khuzestan using the BADI index. Accordingly, in the three dusts investigated in winter and spring of the 2018, different areas within and outside the country supply dust particles in the west of Khuzestan Province. However, it is important to note that internal sources of dust due to proximity to cities and villages in Western Khuzestan are capable of creating dust storms with a radius of less than 1000 m, which makes them more vulnerable.

    Keywords: BADI Algorithm, Dust Storm, Khuzestan Province, Satellite Image
  • Maryam Toorani, Mojtaba Yamani*, Ata Abdelahi Kakroodi Pages 111-126
    Introduction

    Coastal changes are one of the major environmental issues that affect coastal areas around the world. The Caspian shores have been considered by human societies and numerous activities have taken place on the coast. Sea-level changes cause damages. Today, several methods are used to monitor coastlines throughout the world. Remote sensing data is often replaced by field studies. The aim of this study is monitoring the changes of the Caspian Sea coastline in Tajan river coast from 1955 to 2016 in order to identify relationship between coastal displacement and sea level changes and sedimentary changes in this area. In this research, coastal lines have been investigated over a long period of time when the water surface has rapid changes. In addition, the amount of sediment and water discharges have been used as an effective factor in the displacement of coastal lines.

    Materials and Methods

    The study area is located in the Mazandaran province and the middle part of the southern shores of the Caspian Sea, with a geographical position of 36◦48'25'' northern latitude and '53◦05'18'' eastern longitude in the western of the estuary to 36◦49'30'' northern latitude and 53◦09'50'' eastern longitude which is located in the western part of estuary. First, all aerial photographs and digital maps of 1: 25,000 from the National Mapping Organization and Google Earth images of 2013 and 2016 were prepared. Aerial photos were scanned, then carefully georeferenced by Arc GIS 10.3 software. In order to accurately estimate these images, they were matched with 1: 25,000 digital maps. Finally, the coast line was drawn by the Water Line method. In the next step, Google Earth images were received using geospatial elshayel smart software. Again, they were adapted with digital maps of 1: 25,000. Then, the coast line was drown in Arc GIS 10.3 software. The DSAS extension was used in 10.3 Arc GIS software to determine the coastline variation. For this purpose, across the coast, transects were drown perpendicular to the coastline at intervals of 100 meters and then the statistical parameters were extracted. Finally, water and sediment data from Iran Water Resources Management Company were received and the mean water and sediment discharge were calculated individually at each time interval and adapted to the position of the coastline.

    Results and Discussion

    The level of the Caspian Sea has been fluctuating since 1955. For the better study of the shorelines of the Caspian Sea, coastal changes were calculated based on incremental and decreasing sea level cycles. The findings of this study showed that the coastline of Tajan River has not been stable since 1955. In order to achieve the shorelines change in each sea level changes, the statistical parameters for the first period from 1955 to 1977 were examined on the coastlines in this time period. In this section, the EPR, SCE, and the NSM values were 1,765, 25.62, and19.60, respectively. All values in this period are positive and indicate the accretion. The nearest water and sediment station is Kordkhil Station where the water flow rate data is available since 1969 and the sediment discharge data is available since 1981. It does not include the first time zone, so it was not considered for the first time period. The second time period, from 1977 to 1995 includes two series of coastal lines including 1981 and 1994. In this section, the EPR was -11.90, the SCE was 155.22, and the NSM equaled -155.22. This part of the coast in this time have erosion. In the second period of time, the rate of water flux at Kordkhil station is 14.36 m 3 / s and the sediment discharge rate at Kordkhil station is 14802.79 tons per month. The third time has been around since 1995 until now which includes three series of coastlines surveys including 2006, 2013, and 2016. In this section, EPR was 5.95, SCE was 61.26, and NSM equaled 61.24. This part of the coast has a sedimentation status. In the third time period at Kordkhil station, the water flux rate is 9. m 3 / s, and the sediment discharge rate is 42406.5 tons per month.

    Conclusion

    The rise of the sea level causes beach erosion, as it causes water to deepen and finaly causes larger and stronger waves to reach the coast and the sand is transported to the sea. Also, down on the surface of the sea, causing sedimentation. This study in the Tajan River confirms the scientists' view on the role of the sea level at the location of the beaches. In the first period of time, the most changes occurred in the estuarine to the eastern or river, which indicates the effective role of sediments in the estuaries. In addition, moving sediments through longshore current along the western shores of the Caspian Sea is so important. Because these flows move from west to east and divert the sediments to the east. There is a severe erosion of the coast in the second time zone. Rising water prevents sedimentation and the highest rate of erosion in this period is in the eastern part. Totally, in this time, three factors of the sea level increase, increasing water flow, and reducing the sediment discharge can be effective. There is a reduction in the water level during the third period and the rate (EPR) in each transect is different. The highest amount of sediment is found in the estuary of the river and the east of river. The amount of water flood in this period decreased compared to the previous period and the amount of sediment has increased. High sediment supply, reduced water flow, reduced sea level, and expanding location for growing beaches has led to coastal advances towards the sea, and the longshore current moved these sediments to eastward. Finally, according to the results, it can be said that the displacement of the coastline is according to the general rules that scientists have said about the changes in the sea level and the displacement of the coastline.

    Keywords: Caspian Sea, Coastal Variations, Sea Level Changes, Tajan River, Sediment Discharge
  • Raf’at Shahmari Ardejani * Pages 127-141
    Introduction

    Generally less space can be found on the surface of the Earth that is not constantly evolving, so Earth is has a dynamic system as one of its features. In fact, it can be said that active neoconstruction is deforming the surface of the earth. Geomorphological indices represent a useful tool for understanding the functionality and degree of dynamics of these processes. In order to achieve the objectives of the study, seven geomorphologic indices indicate that Korganrud basin is the most active tectonic evidence in the south of the basin in terms of active tectonic deformation. The purpose of preparing geomorphologic maps is recording information about the forms of surface, materials (soils and rocks), surface processes, and, in some cases, the age of land on these maps. The most successful approach to prepare such maps is the combination of field studies with the aerial photographs (Hosseinzadeh, 2007). The first geomorphologic map of Iran, in a scale of 1:2500000, is among a set of maps of the near East in the University of Tubingen in Germany in 1990, which was produced and released by Servati, in collaboration with Bausch and Grounret. Of course, some maps have been prepared by some colleagues of Tehran University, with the scale of 1:250000 and 1:50000. (Jedari Eivazi & Mahmoudi, 1991).

    Materials and Methods

    The research method was based on the analysis of form and process, library data, topographic maps, geological maps, and radar imagery as well as several field survey items. This paper presents eight geomorphological indices of Mountain Frontal Sinusitis (Smf), Drainage Basin Asymmetry (AF), valley floor to Valley Height Ratio (VF), Basin Shape (Bs), Transverse Topography (T), Hipsometric Curve (Hc), maze (S) and longitudinal river (SL) have been used to determine the new tectonic status of Karganud Talesh watershed. This study is a descriptive-analytical study which, based on the purpose, can be functional. Overall, the research process is as follows: the readiness and interest, experience and knowledge about the area, collecting large-scale topographic maps (1:25000) as the base maps, field visits and the observation of objects and phenomena on earth, drawing and producing primary map of land forms, geology and slope maps, analyzing data, aerial and satellite image analysis, and, finally, the analysis of results and producing the final geomorphologic map. Topographic map of 1:25000 and 1:50000, Guilan Faults’ Map 1:250000, Geological map of Rasht-Qazvin 1:100000, Geological map of Ardebil province 1:100000, satellite images of the west of Guilan 1:100000, and Aerial photos of the West of Guilan 1:20000 from the organization of Geological Survey of Iran (published in 1994).

    Results and Discussion

    The results show that Korganrood watershed is one of the mountainous watersheds in northwest of Gilan province and Talesh city. The passage of the Astara-Talesh National Fault about 400 km downstream of the eastern slopes overlooking the Gilan Plain, the Neur Fault near Khalras, and the folds indicate neotectonic activity and the occurrence of important tectonic phenomena in the area. The study area is in the West of Guilan province which starts from the zero point of the border between Iran and Azerbaijan (the town of Astara) and includes the southern parts of Astara city, Talesh, Rezvanshahr, and Masal. It is located between 38 ° 15 ´00 ˝to 38 ° 27 ´00 ˝north latitude of the equator and 48 ° 35 ´00˝ to 49 ° 14 ´00.˝east longitude (topographic map 1:25000) and has 3839/6 square kilometers. This includes about 26/1 % of the total area of Guilan province. The minimum height of the area is 28 meters in Astara coast, and a maximum altitude is about 3197 meters in Baghrouda Castle. The area under study is composed of four distinct morphology sections including: Beaches, Plains, Foothills and Mountains….

    Conclusion

    A direct mountain front indicates active faulting whereas the mountainous bent front shows weak tectonic activity and erosion superiority at altitudes. In this regard, the study area through the Astara-Talesh Fault Pass downstream of the basin as well as the Neur Fault upstream, are in themselves part of the northwestern Gilan tectonic zone. Because geomorphological indices are very important in assessing tectonic activity, they can easily identify areas that have experienced rapid or slow tectonic activity in the past. In this regard, of the geomorphological indices used in this study, only one confirms the inactivity of the basin and the rest all emphasize on the basin's inactivity.
    Mountainous Areas: An average altitude of 1500 meters above the sea level, steep slopes, deep valleys, different streams on the slopes, existence of fault cliffs across the highlands of Talesh, and other issues can be some of the restrictive geomorphologic factors in the development of settlements in the area of the study. Geomorphologic map of the mountainous area shows that the distribution of settlements of Aq Masjid (White Mosque), Baskem Chal, Chamlar, Haji Amir, Vonabin, Heiran, Degarmankshi, Damiroughlikesh, Giladeh, Mashand, Dash Dibi, Baharestan, Latoun is influenced by the geomorphology (shape of the land). The things which are clearly visible in most areas are lack of flat land for the development and expansion of settlements.
    Foothill areas have lower elevation than the surrounding mountainous areas, but compared to the plain areas have higher elevation of 100 to 500 meters with a relatively gentle slope, which extends a distance from mountains and connects to the plain. The main geomorphic elements of foothills region can be alluvial fan, concave and convex slopes, valleys and streams, cliffs, and the water path. Physical expansion of settlements usually encounters an obstacle while developing from one side. At the top of plains, the existence of mountain, high steep, rocks and boulder debris, and overall, sediments are the major obstacles for spatial development.

    Plain Regions

    The plains have higher rank than other units regarding the expansion and the number of urban and rural settlements. Spatial distribution of these kinds of settlements is more regular compared to the mountainous areas, but less regular compared to the foothill ones. The most important cities in the study area, such as Astara, Lavandavil, Choubar, and Haviq are formed in plain units. From among the most important effects of geomorphology in plains of the study area Kanroud, Lavandavil, Cholvand, Choubar, and Haviq rives can be mentioned. As most of these rivers pass through the city, they have left some traces in cities, some of which are river signs around Choubar, Haviq, and Keshli.

    Coastal Areas

    The shores of the Caspian Sea are among the lowland shores and beaches (sand and gravel). The recession and advancement of sea water along with high water levels in aquifers are bottlenecks and geomorphologic obstacles of the area which have changed into environmental problems in releasing urban and industrial wastewater in the city of Astara. It is recommended to prevent the construction of residential houses and structures which contribute to this waste.

    Keywords: Reconstruction, Gilan, Karganrood, Geomorphological indices
  • Vahid Safarian Zengir, Behroz Sobhani*, Majid Rezaei Banafsheh Pages 143-165
    Introduction

    Drought is one of the natural hazards which can cause an irreparable damage in various sectors of agriculture, economics, and so on. In recent years, different regions of the world have experienced more severe drought (Mirzai et al., 2015). Also, drought is one of the most important natural disasters affecting agriculture and water resources which is abundant especially in arid and semi-arid regions (Shamsenya et al., 2008). Drought changes are well-suited for optimal management of water resources utilization (Alizadeh, 2017). Drought is also referred to as a climate phenomenon with a lack of humidity and rainfall relative to normal conditions. This phenomenon strongly affects all aspects of human activity (Zeinali & Safarian Zangir, 2017). Regarding the studies done inside and outside of the country, this study attempted to model and monitor the drought phenomenon in northwest of Iran using a new index.

    Materials and Methods

    In this study, drought modeling in northwest of Iran was carried out using climatic data of rainfall, temperature, sunshine, relative humidity, and wind speed monthly (6 and 12 months scale) for the period of 32 years (1987-2018) in five provinces of Ardebil, East Azarbaijan, West Azarbaijan, Zanjan, and Kordestan in 21 stations using a new index modeling called TIBI architecture, fuzzyized from four indicators (SET, SPI, SEB, MCZI) Valid in World Meteorological Organization. The position of the studied areas are shown in Fig. 1 and the coordinates of the stations are presented in Table (1).

    Results and Discussion

    Monitoring of drought fluctuations based on four integrated indicators in T.I.B.I
    In order to investigate the effect of drought fluctuations in drought conditions of stations, it is possible to find changes in the parameters (SET, SPI, SEB, & MCZI) within the TIBI index. Considering the large number of stations studied, for the sake of better understanding, only the drought series chart of Tabriz station was presented on two 6-and 12-month scale. (In the above-mentioned Station diagram, the Flash line Red shows a 6-month-old drought margin with a value of 0.44 and more, and a 12-month scale with a value of 0.98 and more). The analysis of these forms shows that at the 6 and 12-month scale of Tabriz station, the amount of evapotranspiration was similar to drought conditions, which decreased from March 1993 to July 1998, while after this month an increase was observed. The impact of rainfall on a 6-month scale is weaker than the 12-month scale. From April 1996 to December 2004, it has grown steadily, and then followed the same pattern. The indicators (SET, SPI, SEB, & MCZI) affect the TIBI index and show some trends indicating that the new TIBI fuzzy index is well reflected in the four indicators. Its drought classes scale was presented in Table 5. The T.I.B.I index on a 12-month scale shows a sharper shape compared to a six-month scale.

    Conclusion

    In recent years, drought is one of the most important damaging issues in different sectors such as agriculture, economics, etc. In different parts of Iran including Northwest of Iran, Researchers have done a lot of research on drought monitoring. They presented different models but did not adequately cover the subject. The purpose of this study was to model and investigate drought in northwest of Iran during the 6 and 12-month scale. At stations, the intensity of the 12-month scale and the frequency of droughts are more than 6 months. Drought persistence is more than 12 months old. Drought had a lower continuity in the short-run time scale and was influenced by the temperature parameter. The severity of drought in the long periods of time was less responsive to rainfall variations. The trend of drought in the northwest of Iran increased and the temperature trend was mildly increasing. The most frequent occurrence of drought occurred at the 6th and 12th month scale in Orumiyeh station, while the lowest in both the 6 and 12-month scale in Sanandaj station. The percentage of drought frequency in Jolfa, Maku, and Uromieh stations was 12 months higher than the 6-month scale.

    Keywords: Fuzzy logic, Drought monitoring, 6, 12-month scale, T.I.B.I, North West
  • Sakineh Fajr, Maryam Ilanloo* Pages 167-184
    Introduction

    Landscape is an arrangement in which a combination of local ecosystems or land uses is repeated in a similar region (Apan, Raine, & Paterson, 2002). The landscape of the land is a dynamic system and humans are constantly influenced by it. Depending on the severity of the impact on human landscape, the pressure and changes that occur will result in a change in landscape over time (Gökyer, 2013). Landscape around the world is changing rapidly due to urbanization and population growth (Karami &Jurisprudence, 2011). A major concern of this rapid development is its profound impact on urban ecosystems and biodiversity due to fragmentation. This has increased interest among ecology researchers to study the structure of urban landscapes and the environmental implications of physical urban development (Fan & Myint, 2017). The purpose of this study is to examine the trend of spatial-temporal change over the last 20 years (from 1998 to 2018). In Abadan, Mahshahr, Bandar Imam Khomeini (RA) and Kharshamr coastal cities, for the first time, using land use metrics to analyze and provide strategies and strategies for improving quality planning.

    Material and Methods

    The research method is quantitative and the logic is inductive. The research approach is descriptive and is used to understand the nature of the topic. Data were collected through Landsat satellite imagery from two years 2018 and 1998 captured by OLI and MSS5 sensors with a resolution of 30 m, which transformed Landsat 8 satellite image to 15 m in ENVI 5.3 software. To extract the land cover map and detect changes in classification images, the images were categorized into four main classes (residential), vegetated areas, wetlands (rivers), and Bayer according to land cover. Fragstats software was then used to extract land cover measurements at two levels of the classroom and the simulator. A total of 8 landscapes were quantified by land landscape quantification.

    Results and Discussion

    The area and the percentage of land cover coverage in the classrooms have increased in each of the four cities over the past four years, with the addition of residential areas. Vegetation land use in two cities of Khorramshahr and Abadan has been decreasing, while in two cities of Imam Khomeini Port and Mahshahr Port it has been increasing. The highest change in the number of spots during this time period was due to the class of residential areas, indicating an increase in fragmentation, congestion, and disturbance in the land resulting from the expansion of residential areas. The decline in the largest blotch indicates the destruction of vegetation and wildlife classes due to increased urbanization. This is more severe in Abadan and Khorramshahr than in Bandaram Khomeini and Mahshahr. The effect of fragmentation of landscape in Abadan City is visible with increasing stain density and fringe density. In all four cities, vegetation cover was higher than residential areas, which means that vegetation margins were more frequently treated. Another point to note is that the amount of margin density in Khorramshahr City did not increase during the period under study, whereas it had a decreasing trend in all four classes. However, the other three cities had an increasing trend. The patch density index varied across the four cities; therefore, in Abadan and Khorramshahr all classes in the residential class in the study period followed an increasing trend, indicating an increase in land fragmentation in this city. In Mahshahr and Bandaram Khomeini, all four classes have had an increasing trend.
    At the landscape level of Abadan, landscape has aggregation, attrition and dissection. Attrition index corresponds to wastewater and water resources classes, aggregation index to urban areas and dissection index to vegetation areas in the region. I the port city of Imam Khomeini there are two indicators of aggregation and attrition. The attrition index corresponds to the Bay Area and the aggregation index to the vegetation use and residential areas.
    Khorramshahr has landscapes of creation, attrition and dissection. The attrition index corresponds to Bayer, creation index (number and area of patches) to residential areas and water resources, and the dissection index to vegetation area in the region. Attrition index corresponds to waste land and water resources, the creation index to vegetation cover, and the aggregation index to the residential area.

    Conclusion

    The purpose of this study is to investigate land use changes in Abadan, Khorramshahr, Bandaram Khomeini (Rah) and Mahshahr ports in four coastal and industrial cities of Khuzestan Province using land use measures. The present results can be used as a suitable approach to study the trend of land cover changes in the four cities studied and a road map for formulating long-term plans. Given the uncontrolled growth of residential and agricultural land over the past twenty years, to prevent further damage and to preserve cover. It is also suggested to model the development of cities in the southern provinces of the country based on different development scenarios and its results to be used for better decision making in urban development management and planning.

    Keywords: Spatial-temporal changes, Landscape metrics, Fragstats software, coastal cities, land use
  • Peyman Yariyan, Mohammadreza Karami* Pages 185-203
    Introduction

    The population of cities is on the rise and is constantly exposed to a variety of human and environmental hazards (Alexander, 1993). Earthquake is one of the most important disasters affecting cities and urban land use. Natural disasters such as earthquakes have been a serious and permanent threat to humans and human settlements, which have endangered human life in areas with high seismicity. That is why it was named as the deadliest natural disaster in the world in 2001. Iran is also one of the most earthquake-prone countries in the world, which has always witnessed high casualties in its cities due to this disaster (WDI, 2004). Meanwhile, the occurrence of any earthquake in urban such as Sanandaj in Kurdistan Province has negative and irreversible effects on the whole region. Therefore, the assessment of urban vulnerability caused by earthquake, despite Morvarid Faults, Sartakht, etc. in Zagros Mountains is necessary. The purpose of this study is to assess the vulnerability of Sanandaj City due to earthquake with an emphasis on uncertainty approach using FAHP model. In addition, a comparison is made between the AHP and FAHP models.

    Materials and Methods

    In this study, three environmental, physical and social factors with 13 criteria were selected. The selection of criteria has been based on previous studies, and it has been attempted to select the variables that have the most relevance and impact. Layer maps were obtained in the form of raster and vector data from formal offices. After editing and correcting for possible errors, all layers in ArcGIS software were converted to raster format. The layers were then standardized. According to the studies, the weight of each layer (AHP model weights 1-9) and their fuzzy thresholds were then determined. Finally, the final result in five vulnerability classes (i.e. very low, low, medium, high and very high) were identified. The maximum-minimum method was used to standardize the layers. After standardization in ArcGIS 10.4 software, pairwise comparisons matrix was formed through the AHP method. By introducing initial weights, final weights and AHP map was obtained. In order to implement the FAHP model, after identifying the type of membership function and increasing or decreasing the amount of each layer, the fuzzy method was used in IDRISI software environment. Then, in ArcGIS software using Raster calculator tool, each of the fuzzy layers was multiplied and aggregated in the final weight of the AHP model. First, each fuzzy layer was multiplied individually in its own weight using the Raster calculator tool. Then, the new maps were executed by five fuzzy operators (SUM, GAMMA, OR, AND, PRODUCT) and the final map was prepared based on SUM operator as the best operator, which is most consistent with the current situation in Sanandaj.

    Results and Discussion

    Based on the results of both AHP and FAHP models, most areas with high physical vulnerability have undesirable characteristics such as poor quality of materials, burnout and high density land use. From social perspectives, they also have high population density, which corresponds to worn-out textures and marginalized neighborhoods. However, comparing the two AHP and FAHP models shows the higher accuracy of the FAHP model. In general, the FAHP model is highly capable of formulating the uncertainties of the present study.

    Conclusion

    While the AHP method uses quantitative and qualitative variables, it is not capable of modeling uncertainty about decisions makers. One of the capabilities of the Fuzzy-AHP model in this study is to utilize different spectra through normalization methods based on minimization and maximization. This method eliminates the uncertainty in the ranking of actions and decisions in the AHP method. Accordingly, zones 1, 2, and 3, respectively, are most vulnerable to earthquake, which are consistent with the worn-out texture and margin of the city. The district 1 of Sanandaj, districts such as Ghatarchian, Tazeh abad, Haji Abad, Besat and district 2 in Abbas Abad, Golshan, Pir Mohammad and finally district 3 in Mubarak Abad, Kalaka Jar, Vila shahr and Baharan Town are highly vulnerable. In general, zones 1, 2, and 3, respectively, are the most zones vulnerable, which are highly adapted to the worn-out texture and margin of the city. Therefore, the most important proposal of this study is comprehensive planning and construction operations in the suburbs and worn-out areas, which should be regarded as a priority to deal with possible earthquakes.

    Keywords: Uncertainty, Earthquake Risk Assessment, Fuzzy-AHP Logic, Modeling, Sanandaj
  • Fateme Feyzi Koushki, Morteza Akbari*, Hadi Memarian, Mahmud Azamirad Pages 205-225
    Introduction

    Desertification is one of the most complex environmental threats with negative socio-economic impacts. Understanding the spatio-temporal characteristics of this process is possible by identifying, monitoring, and evaluating important criteria and indicators (Akbari, Ownegh, Asgari, Sadoddin, & Khosravi, 2016). Each of the criteria, effective in desertification can include several important indicators. For each indicator, accurate identification and evaluation of the effective mechanisms and its role in desertification will contribute significantly to proper land management. Many studies have been done on desertification. However, researchers believe that desertification can only be satisfactorily evaluated when appropriate and valid criteria and indices are determined. So far, it has not been possible to determine indicators that can be used at different global, regional, national, and local levels (Akbari, 2016; Akbari, Jafari Shalamzari, Memarian, & Gholami, 2020). Therefore, this research, with an exploratory approach, attempts to identify and formulate the main and key factors affecting desertification expansion in Khorasan Razavi province. Identification and prioritization of key desertification factors based on expert opinions, field studies, and scientific approaches can play an important role in better management of Khorasan Razavi province.

    Study Area

    The study region, with an area of 11.6 million hectares and a population more than 6 million people (8 % of Iran's population), is located at 56o 30' to 61o 10’ E and 34o 15’ to 37o 42’ N. This area is adjacent to Turkmenistan in the north and northeast, running a border of 531.6 km, and to Afghanistan in the east, with a border length of 302 km (Feyzi Koushki, Akbari, Memarian, & Azamirad, 2019(. Official reports existing in the Department of Natural Resources and Watershed Management of Khorasan Razavi Province have shown that increasing the number of wells, conversion of rangeland and forest to agricultural and residential land and land salinization have been effective human factors in land degradation. According to official reports, soil erosion per capita in Iran is about 15 tons per hectare per year, which is estimated to be about 18 to 20 tons per year for Khorasan Razavi province, indicating the intensity of soil erosion in eastern parts of Iran (Akbari, Neamatollahi, & Neamatollahi, 2019).

    Material and Methods

    Two methods were used for data collection. First, a number of different desertification intensity models and significant factors affecting the desertification process were evaluated. Then, a questionnaire was designed to determine uncertainties based on the initial round of questionnaires distributed among the statistical population (including 113 experts and specialists). The responses were subsequently assessed based on the Delphi method (Feyzi Koushki, Akbari, Memarian, & Azamirad, 2019). In this study, field studies were used as the basis for designing questionnaires. The required data were collected to design a questionnaire by the defined standards. The questions were answered on a 5-point Likert scale (low to negligible, low, moderate, high and very high). The ranking scale was used to evaluate the indices for data extraction and analysis were used. The statistical population initially comprised of 130 experts, executives, and specialists in the field of natural resources and environment. Questionnaires were distributed among the statistical population in two rounds using the Delphi method. The Friedman test was also used to compare the mean scores.

    Results and Discussion

    In this study, the validity of the questionnaires was approved through expert opinion. Finally, ten questions (from 90 questions) were omitted and some of the questions were adjusted. The reliability of the questionnaire was determined by Cronbach's alpha coefficient. Cronbach's alpha was calculated as 0.823 using SPSS (statistical package for social sciences). The results of the first round of Delphi showed that the most important desertification criteria were climate, water, human activities, socio-economic criteria, vegetation, agricultural activities, soil, geology, and erosion criteria, respectively. In the second step, after analyzing the questionnaires, human activities, climate, water, socio-economic criteria, vegetation, agricultural activities, soil and geology, and erosion criteria were ranked as the most important criteria, respectively.

    Conclusion

    The most important desertification criteria in Khorasan Razavi province were ranked using the Delphi method by evaluating the main effective desertification factors based on the opinions of experts in the field of natural resources. The results showed that human activities, climate, water, socio-economic criteria, agricultural activities, vegetation, soil and geology, and erosion criteria were important factors in desertification expansion. The results of this study will be useful for developing management plans and reducing the negative impacts of land degradation. It is recommended to use appropriate statistical methods for assessing the status of land degradation and desertification risk and to prioritize effective factors and criteria for presenting appropriate solutions. Therefore, this exploratory research attempts to identify and formulate the main and key factors affecting desertification expansion in Khorasan Razavi province. Identification and prioritization of key desertification factors based on expert opinions, field studies, and scientific approaches can play an important role in better management of Khorasan Razavi province.

    Keywords: Desertification intensity, Land degradation, Indices, Statistical analysis, Questionnaire