فهرست مطالب

جغرافیا و مخاطرات محیطی - پیاپی 25 (بهار 1397)

نشریه جغرافیا و مخاطرات محیطی
پیاپی 25 (بهار 1397)

  • تاریخ انتشار: 1397/03/30
  • تعداد عناوین: 10
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  • محمدحسین رضایی مقدم *، مهدی یاسی، محمدرضا نیکجو، مسعود رحیمی صفحات 1-15

    سیلاب ها ازجمله مخاطرات طبیعی هستند که هرساله خسارات بسیار زیادی را برای ساکنین دشت های سیلابی به بار می آورد. تهیه نقشه های پهنه بندی سیلاب برای دوره های بازگشت مختلف ازجمله روش های متداولی است که جهت نمایش پتانسیل مخاطرات سیلابی مورداستفاده قرار می گیرد. در پژوهش حاضر، که خطر وقوع سیلاب را در 72 کیلومتر از رودخانه قره سو در محدوده استان اردبیل موردبررسی قرار می دهد، جهت شبیه سازی سیلاب از مدل هیدرودینامیکی یک بعدی HEC-RAS استفاده شد و پیش پردازش و پس پردازش داده های ژئومتری و هیدرومتری در محیط نرم افزاری GIS توسط الحاقی HEC-GeoRAS صورت پذیرفت. نتایج پهنه بندی سیلاب رودخانه قره سو نشان داد که با رخداد سیلابی با دوره بازگشت 25 سال، مساحتی در حدود 1085 هکتار از اراضی کشاورزی و باغات حاشیه رودخانه قره سو به زیرآب رفته و خساراتی را برای کشاورزان این منطقه به وجود خواهد آورد. همچنین نتایج نشان داده که عرض پهنای سیل گیر برای دوره بازگشت 25 سال در بازه های دوم، سوم و چهارم تا 550 متر نیز می رسد. بر این اساس لزوم توجه به اقدامات اساسی در زمینه مدیریت دشت های سیلابی در این منطقه ضرورت می یابد.

    کلیدواژگان: پهنه بندی سیلاب، مدل هیدرودینامیکی HEC-RAS، دشت سیلابی، دوره بازگشت، قره سو
  • منیره رعیتی شوازی، حمیدرضا غفاریان مالمیری، عادل سپهر، امیر کرم * صفحات 17-36
    بررسی و تحلیل اطلاعات مکانی و زمانی لندفرم ها و کاربری اراضی با استفاده از داده های چند زمانه از جمله مباحثی است که در مطالعات بیابان زایی و تحلیل روند تغییرات آن حائز اهمیت است. پژوهش حاضر با استفاده از تکنولوژی سنجش ازدور، به شناسایی و تحلیل تغییرات لندفرم های ژئومورفولوژی و کاربری اراضی در بخشی از دشت یزد-اردکان پرداخته است. بدین منظور از تصاویر سنجنده های TM و OLI ماهواره Landsat مربوط به سال های 1987 و 2016، در بازۀ زمانی 30 ساله استفاده شد. ابتدا تصحیحات لازم بر روی تصاویر انجام گردید و سپس بر اساس نقشه های توپوگرافی، ژئومورفولوژی و تصاویر گوگل ارث، لندفرم های ژئومورفولوژی و طبقات کاربری اراضی منطقه مورد مطالعه تعریف و نمونه های آموزشی انتخاب گردید. سپس تصاویر با الگوریتم حداکثر احتمال طبقه بندی و نقشه لندفرم ها و کاربری اراضی تهیه شد. دقت تصاویر طبقه بندی نیز با ضریب کاپا و دقت کلی محاسبه شد. درنهایت به منظور شناخت وضعیت تغییرات لندفرم ها از روش آشکارسازی تغییرات "پس از طبقه بندی" استفاده شد. نتایج نشان داد که لندفرم های موجود بروی دشت سر پوشیده به جز تپه های ماسه ای مواج دارای روند نزولی تا سال 2016 بودند و این در حالی است که مناطق شهری و اراضی زراعی و باغات و جنگل های دست کاشت که بروی دشت سر پوشیده بودند، طبق تغییرات کاربری اراضی دارای روند صعودی بوده اند؛ و به طورکلی این نتایج نمایانگر آن است که در محدوده مورد مطالعه در طی 30 سال، نه تنها بر وسعت اراضی بیابانی افزوده نشده است، بلکه از محدوده اراضی بیابانی کاسته شده و بر دیگر کاربری ها افزوده شده است. همچنین در شرق و غرب منطقه مرز لندفرم ها تغییر کرده است.
    کلیدواژگان: تغییرات مکانی-زمانی، لندفرم، کاربری اراضی، بیابان زایی، حداکثر احتمال، دشت یزد-اردکان
  • غلامرضا مقامی مقیم *، امین نویدطلب صفحات 37-55
    دیاپیریسم نمکی فرآیندی است که در طی آن یک لایه از کانی های تبخیری به درون لایه های فوقانی نفوذ نموده¬ سبب شکل گیری ناهمواری های ویژه ای می شود. این ناهمواری ها به دلیل وجود منابع نفتی، استقرار سکونت گاه¬های انسانی و عبور راه های ارتباطی اهمیت زیادی دارند. منطقه موردمطالعه که در شرق شهرستان شاهرود قرار دارد، یکی از مناطقی است که تحت تاثیر دیاپیریسم نمکی، ناهمواری های ویژه ای چون گنبدهای نمکی، درز و شکستگی، چین های ثانویه، کارست های نمکی، دره ها، پلیگون¬ها، یخچال ها، چشمه ها، اشکال گل کلمی و مخروط های نمکی در آن شکل گرفته است. دیاپیریسم نمکی از طریق تاثیرگذاری در شبکه حمل ونقل و به خصوص شبکه ریلی می تواند سبب مشکلات و حوادث جبران ناپذیر گردد. در این مقاله با استفاده از روش های میدانی و داده های سنجش ازدور تاثیر دیاپیریسم نمکی روی خط آهن شاهرود – مشهد حدفاصل ایستگاه شاهرود- بکران مورد بررسی قرار گرفت و مشخص شد خط آهن مشهد – شاهرود در محدوده شاهرود به بکران در معرض شدید مخاطرات ناشی از دیاپیریسم نمکی ازجمله ریزش سینک هول های نمکی، یخچال های نمکی، رودخانه های نمکی و پونورهای نمکی قرار دارد. همچنین بر اساس نتایج حاصل از مطالعات کمی که به روش INH انجام شد، فروچاله¬ها و چاه های نمکی از گروه کارست های نمکی به ترتیب با ضرایب 37/1 و 50/1 دارای تاثیرات شدید، پونور ها و رودخانه های نمکی به ترتیب با 62/1 و 75/1 در ردیف خطرات با تاثیرگذاری زیاد، یخچال ها، پولیگون¬ها، گنبدهای نمکی و اشکال تبخیری هر یک با 2، طاقدیس جیلان و مخروط های نمکی با 42/2 دره ها و چشمه های نمکی با 14/2 دارای تاثیرگذاری متوسط و کلوت¬های نمکی با 57/2 کمترین تاثیرات را روی راه آهن شاهرود- مشهد دارند.
    کلیدواژگان: دیاپیریسم نمکی، خط آهن، کارست های نمکی، طاقدیس جیلان
  • حمید ابراهیمی *، علی اکبر رسولی، داوود مختاری صفحات 57-73
    آتش سوزی در عرصه های طبیعی نه فقط از دیدگاه محیط زیست، بلکه از نظر اقتصادی، اجتماعی و امنیتی ازجمله اصلی ترین نگرانی ها و چالش های موجود در بسیاری از نقاط جهان است. ازجمله معضلات پیش روی مدیریت جنگل ها و مراتع استان آذربایجان شرقی، آتش سوزی هایی است که سالانه خسارات زیست محیطی و مالی زیادی را به استان وارد می کند؛ ازاین رو بررسی و تحلیل تغییرات وضعیت منطقه از نظر خطر آتش سوزی و همچنین پارامترهای مؤثر بر آن در زمینه رویکرد¬های مدیریتی و کنترلی بحران آتش سوزی بسیار کاربردی خواهد بود. فرآیند پژوهش حاضر در سه بخش به انجام رسیده است؛ نخست با مطالعه مبانی نظری موضوع، 12 پارامتر (تراکم مراکز سکونتی، فاصله از مراکز سکونتی، تراکم شبکه ارتباطی، فاصله از شبکه ارتباطی، ارتفاع، شیب، جهت شیب، حداکثر دمای ماهانه، حداقل دمای ماهانه، میانگین دمای ماهانه، بارندگی سالیانه و پوشش گیاهی) به عنوان عوامل مؤثر در تحلیل خطر آتش سوزی در جنگل ها و مراتع شناسایی و با استفاده از منابع اطلاعاتی موجود و تکنیک های مختلف و متناسب مبتنی بر سیستم اطلاعات جغرافیایی و سنجش از دور، نقشه های مربوط به معیارهای موردنظر تولید گردیده است. در ادامه با استفاده از داده های مربوط به آتش سوزی های صورت گرفته و عوامل زیست محیطی- انسانی ایجادشده، در بستر مدل حداکثر بی¬نظمی به مدل سازی خطر آتش سوزی در جنگل¬ها و مراتع استان آذربایجان شرقی در سه دوره زمانی (1386-1388، 1389-1391 و 1392-1394) پرداخته شد. نتایج حاصل از ارزیابی مدل با استفاده از تکنیک مساحت سطح زیر منحنی ویژگی عامل دریافت کننده، حاکی از کارایی بسیار بالا و مناسب مدل های اجراشده (91/0، 82/0 و 83/0) می-باشد. در مرحله پایانی پژوهش، بر اساس نتایج حاصل بیشترین میزان تغییرات مربوط به کاهش مساحت پهنه های با خطر بسیار کم و افزایش مساحت اراضی واقع در پهنه های با خطر متوسط و بسیار پرخطر است. همچنین بررسی عوامل مؤثر بر وقوع آتش سوزی نشان دهنده تغییرات گسترده در تاثیرگذاری این عوامل و افزایش نقش عوامل انسانی در طی دوره مورد بررسی می باشد؛ به صورتی که در دوره سوم عوامل تراکم مراکز سکونتی و فاصله از شبکه ارتباطی بیشترین تاثیر را بر وقوع آتش سوزی ها داشته اند.
    کلیدواژگان: آتش سوزی، تحلیل خطر، مدل حداکثر بی نظمی، جنگل ها و مراتع، آذربایجان شرقی
  • سحر گودرزی، علی طالبی *، حمیدرضا پورقاسمی صفحات 75-96

    زمین لغزش ازجمله بلایای طبیعی است که بیشتر در مناطق کوهستانی رخ می دهد و مورفولوژی را به طور ناگهانی تغییر داده و خسارت¬های عمده ای به ¬مناطق مسکونی، جاده ها زمین¬های کشاورزی و غیره وارد می سازد. هدف از تحقیق حاضر تهیه نقشه حساسیت زمین لغزش با استفاده از سیستم استنتاج عصبی-فازی تطبیقی در حوزه آبخیز سردارآباد واقع در استان لرستان است. به این منظور با استفاده از تصاویر ماهواره ای و بازدیدهای صحرایی، 109 پهنه لغزشی شناسایی و نقشه پراکنش زمین لغزش های منطقه مورد مطالعه تهیه گردید. لایه¬های اطلاعاتی ارتفاع، سنگ شناسی، درجه شیب، جهت شیب، شکل شیب، فاصله از رودخانه، فاصله از جاده، فاصله از گسل، بارندگی و کاربری اراضی به عنوان عوامل موثر بر وقوع زمین لغزش شناسایی و نقشه های مذکور در محیط نرم افزار ArcGIS تهیه و رقومی گردیدند. به منظور وزن دهی کلاس های هر یک از عوامل از روش نسبت فراوانی استفاده گردید؛ سپس وزن های به دست آمده نرمال سازی شده و به محیط نرم افزار Matlab2015a منتقل گردید. در تحقیق حاضر از ساختار سیستم استنتاج فازی خوشه¬بندی (کلاسترینگ) برای پهنه بندی حساسیت زمین لغزش استفاده گردید. به منظور ارزیابی مدل ها از منحنی راک استفاده شد. نتایج ارزیابی نشان داد که دقت مدل تهیه شده با استفاده از سیستم استنتاج عصبی- فازی تطبیقی در منطقه موردمطالعه 11/89 درصد (خیلی خوب) برآورد شده است. نقشه حساسیت لغزش نیز نشان داد که مساحت مناطق با حساسیت متوسط 29درصد، حساسیت زیاد 23درصد و حساسیت خیلی زیاد 12درصد است. در مجموع مساحت مناطق متوسط، زیاد و خیلی زیاد 64درصد بوده که نشان¬دهنده پتانسیل خطرپذیری بالای حوزه آبخیز سردارآباد در بروز لغزش¬ها است.

    کلیدواژگان: حوزه آبخیز، زمین لغزش، سیستم استنتاج عصبی- فازی تطبیقی، منحنی راک، منطقه سردارآباد
  • حسن اروجی، حمید زمانی، زهرا عربی * صفحات 97-114
    با توجه به اهمیت عامل اقلیم در سنجش وضعیت مقصدهای گردشگری، توجه و ارزیابی به این عامل از طریق ارائه شاخص¬ها و دیدگاه¬های مختلف افزایش یافته است و در این میان تاکید بر داده ها و ارزیابی های میدانی مبتنی بر سنجش دیدگاه ها و رضایتمندی¬های گردشگران، در کنار توجه به شاخص های استاندارد اقلیم گردشگری و دیدگاه های کارشناسانه، می تواند تصویر واقع بینانه تری را از شرایط اقلیمی برای گردشگری ارائه دهد. با توجه به تفاوت های طبیعی و انسانی بین مقاصد گردشگری و بین گردشگران، هدف این پژوهش، سنجش شرایط اقلیمی برای گردشگران با ترکیب رضایتمندی گردشگران با داده های کارشناسی و اصلاح و بازبینی در شاخص های قبلی است و برای این منظور، جزیره قشم به عنوان مطالعه موردی انتخاب شده است. به منظور ارزیابی شرایط اقلیمی، شاخص های PMV، PET و CIT به صورت ترکیبی برای ایستگاه ساحلی جزیره قشم و در دوره آماری 2003-2014 مورد سنجش قرار گرفت. نتایج ارزیابی ها، نشانگر نکته قابل توجهی بود. با وجود مطلوبیت اقلیم گردشگری برای ماه های سرد سال و ساعات شبانه در جزیره قشم، از منظر شاخص CIT، کلیه ماه های سال و همچنین کلیه مقاطع شبانه روز (به جز ساعات روزانه ماه های تابستان) از شرایط مطلوب یا قابل قبول برای گردشگری برخوردار بودند که کمی با شرایط منطقه ناسازگار به نظر می رسید. با توجه به تفاوت های طبیعی و انسانی بین مقصدها و بین گردشگران، بازبینی مختصری در شاخص CIT صورت گرفت و با ترکیب نتایج شاخص PMV و میزان رضایتمندی گردشگران از شرایط حرارتی مختلف، نتایج جدیدی برای اقلیم گردشگری جزیره حاصل شد که نشان می دهد جزیره قشم در نیمی از سال (از ماه می تا اکتبر) و کلیه ساعات شبانه روز در همین بازه زمانی، از شرایط مطلوب یا قابل قبول فاصله دارد. علت متفاوت بودن نتایج فعلی، دخالت دادن مستقیم رضایتمندی گردشگران در داده های اقلیمی است.
    کلیدواژگان: اقلیم گردشگری، شاخص CIT، جزیره قشم
  • عباسعلی آروین * صفحات 115-129
    آلودگی هوا یکی از علل ایجاد جزیره حرارتی شهر است که در شهرهای بزرگ از جمله اصفهان به دلیل تراکم بالای جمعیت و به دنبال آن افزایش تعداد روزهای آلوده، رخداد آن در سال¬های اخیر رو به افزایش بوده است. در این پژوهش به دلیل فقدان داده¬های دمایی سطح شهر، ابتدا با استفاده از تصاویر ماهواره¬ای لندست 8 و با بهره¬گیری از روش آلگوریتم پنجره مجزای سوبرینو دمای سطح زمین (LST) محاسبه گردید و در ادامه جزیره حرارتی شهر با استفاده از روابط آماری بدست آمد. نتایج نشان داد اختلاف دمای LST با دمای خاک در عمق 5 سانتیی متری در موقعیت ایستگاه¬های هواشناسی به¬طور متوسط 1/4 سلسیوس است و در حداکثر مقدار به 9/5 درجه می¬رسد. بررسی دمای هوای تخمین زده شده برای شهر اصفهان نشان داد اختلاف دمای جزیره حرارت هوای شهری و دمای پیرامونی شهر در زمان رخداد حداکثر آلود¬گی بیشتر است. نقشه¬های جزیره حرارتی و نقشه¬های توزیع آلودگی بر یکدیگر انطباق داشته و نواحی آلوده¬تر دارای دماهای بالاتری بوده¬اند. همچنین روابط همبستگی بین نقشه توزیع آلودگی و نقشه جزیره حرارتی شهر اصفهان در سطح معناداری تایید ¬شد و در روزهای با آلودگی بیشتر، ضرایب همبستگی مذکور قوی¬تر هستند.
    کلیدواژگان: جزیره حرارتی، اصفهان، تصاویر ماهواره ای، آلودگی هوا، تخمینن دما
  • مسعود جلالی، الله مراد طاهریان، مهدی دوستکامیان * صفحات 131-152
    بررسی سازوکار انتقال و شناسایی منابع تامین رطوبت بارش های یک منطقه و شناخت مؤلفه های چرخه آب بر روی آن از موضوعات موردتوجه در علوم جوی است. پژوهش حاضر باهدف مطالعه شار همگرایی رطوبت و آب قابل بارش جو و شناسایی منابع تامین رطوبت بارش های بهاره ایران صورت گرفته است. برای این منظور از داده¬های بارش روزانه 483 ایستگاه سینوپتیکی، کلیماتولوژی و باران سنجی در یک دوره آماری 50 ساله (1961- 2010) استفاده شده است. پس از استخراج روزهای بارشی فراگیر به کمک تحلیل خوشه¬ای الگوهای شار همگرایی رطوبت و آب قابل بارش جو بارش بهاره شناسایی شده اند و سپس اقدام به استخراج نقشه¬های فشار تراز دریا، 850 و 700 هکتوپاسکال به همراه شار همگرایی رطوبتی و آب قابل بارش جو در منطقه موردمطالعه شده است. نتایج نشان داد که مکانیسم بارش های فراگیر بهارۀ ایران و شار همگرایی رطوبت در ارتباط با همگرایی شار رطوبتی ناشی پرفشار سیبری- کم فشار عربستان ، شار همگرایی رطوبت ناشی از پرفشار قزاقستان – کم فشار خلیج فارس، شار همگرایی رطوبت ناشی از پرفشار شمال دریای خزر-کم فشار شرق ترکیه، کم فشار عربستان، شار همگرایی رطوبت ناشی از پرفشار سیبری- کم فشار عربستان، سودان و شار همگرایی رطوبت ناشی از پرفشار سیبری – کم فشار ترکمنستان، کم فشار سودان بوده است. بیشترین مقدار رطوبت و شار همگرایی رطوبت از سمت دریای عرب، خلیج¬فارس، دریای خزر و دریای سرخ در ترازهای پایین جو و دریای مدیترانه و سیاه درترازهای بالایی جو است.
    کلیدواژگان: شارهمگرایی رطوبت، آب قابل بارش، بارش های بهاره، ایران
  • حجت الله دانشمند، پیمان محمودی * صفحات 153-168
    هدف اصلی این پژوهش آشکارسازی رفتار دوره ای خشکسالی های ماهانه ایران است. برای رسیدن به این هدف ابتدا بارش روزانه 41 ایستگاه همدید کشور برای یک دورۀ آماری 31 ساله (2013–1983) از سازمان هواشناسی کشور دریافت گردید. سپس شاخص خشکسالی مؤثر (EDI) در مقیاس زمانی ماهانه محاسبه و رفتار دوره ای سری های زمانی شاخص خشکسالی مؤثر (EDI) ایستگاه ها با استفاده از تحلیل موجک مورد بررسی قرار گرفت. نتایج این تحقیق نشان داد که دوره های تناوبی موجود در سری های زمانی شاخص خشکسالی مؤثر (EDI) ایستگاه های مورد مطالعه در ایران بسیار متنوع بوده و از بازه-های تناوبی 28- 24 ماهه تا 220- 210 ماهه را شامل می شود. علاوه بر این، در تعدادی از ایستگاه های مورد مطالعه، بازه ها ی تناوبی غالب به چشم می خورد. از جمله بازه های تناوبی غالب می توان به دو بازه 120- 108 ماهه و 80- 60 ماهه اشاره کرد. ولی در مجموع درکل ایستگاه ها این بازه های تناوبی غالب مشاهده نمی شود. همچنین در اکثر ایستگاه¬ها بازه تناوبی در طول سری زمانی نغییر می¬کند. در تمام نواحی به¬جز ناحیه نیمه شمالی ایران مرکزی، پهنای نوار تناوبی در حال افزایش است. به عبارت دیگر نوار تناوبی به سمت بازشدگی است. در اوایل سری¬های زمانی، نوارهای تناوبی دارای پهنای کمتری بوده و دوره¬های کوتاه¬تری را شامل می¬شوند؛ اما با نزدیک شدن به اواخر سری¬های زمانی، پهنای نوارهای تناوبی بزرگتر شده و دوره¬های بلندتری را شامل می¬شوند. بنابراین در کل ایران می¬توان نتیجه گرفت که بازه¬های تناوبی با شیب خیلی ملایمی به سمت دوره¬های بلندمدت متمایل می¬شود.
    کلیدواژگان: خشکسالی، تبدیل موجک، بسامد، باز? تناوب
  • محمد جواد یوسفی ، علیرضا راشکی *، محمد فرزام، محمد تقی کاشکی صفحات 169-185
    در مناطق غربی و جنوبی شهرستان سرخس نبکاهای زیادی گسترش دارند که نشان¬دهنده فعالیت بادی و حمل رسوبات است که توسط پوشش گیاهی کنترل شده¬اند. ریخت شناسی و کانی¬های رسوبات نبکاها جدا از اینکه به خصوصیات گیاهان تشکیل دهنده آن ارتباط دارند می¬تواند اطلاعات مناسبی از محیط شکل¬گیری و منشا رسوبات فراهم کند. نبکاها باعث به وجود آوردن جزایر حاصلخیزی در یک منطقه می¬گردند. برای سنجش و رصد عملکرد نبکاها و همچنین بررسی روند تغییرات شاخص¬های مرفولوژی گیاهان به وجود آورندۀ نبکا و نحوۀ تغییرات دانه¬بندی رسوبات بادی نبکا، تعداد 120 عدد نبکا در 3 سایت از شمال تا جنوب نبکازارهای غرب شهرستان سرخس مورد بررسی قرار گرفت. برای هر نبکا پارامتر¬های مرفولوژی گیاه و مرفومتری نبکا مورد نیاز از قبیل ارتفاع، طول و حجم نبکا و ارتفاع، قطر بزرگ، حجم و محیط گیاه مورد ارزیابی قرار گرفت و بررسی ضریب همبستگی و تبیین بین شاخص-های مرفولوژی گیاه با شاخص¬های مرفومتری نبکا صورت پذیرفت. همچنین رسوبات نبکاهای بررسی شده مورد آزمایش¬های تعیین بافت رسوب، کانی¬شناسی، pH، EC و دانه¬بندی قرار گرفتند و نتایج آزمایش¬ها با روند تغییرات پارامترهای بررسی شده از گیاه، نبکا و رسوبات مورد بررسی قرار گرفتند. بر طبق نتایج آزمایش های دانه¬بندی و کانی¬شناسی و جهت باد غالب، محل برداشت رسوبات از فاصلۀ حدود 50 کیلومتری در جنوب کشور ترکمنستان است. همچنین مشخص گردید در منطقه با افزایش مسافت حمل رسوب میزان EC کاهش و بر میزان pH رسوبات افزوده می¬گردد. از میان شاخص¬های مرفولوژی گیاهی بررسی شده شاخص¬های حجم گیاه تاثیر بیشتری بر روی حجم نبکا¬ی به وجود آمده دارند. همچنین تاثیر حجم و ارتفاع گیاه بر شاخص¬های D10، D50، D90 و میانگین قطر رسوبات بیشتر از تاثیر شاخص مسافت حمل رسوب است؛ اما بر روی شاخص کشیدگی رسوبات بیشترین عامل مؤثر مسافت حمل رسوب می¬باشد.
    کلیدواژگان: سرخس، کانی شناسی، دانه بندی، نبکا، مرفومتری
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  • Mohammad Hossein Rezaei Moghaddam *, Mehdi Yasi, Mohammad Reaza Nikjoo, Masoud Rahimi Pages 1-15
    Introduction

    Nowadays floods are considered as one of the greatest threats in terms of social security and sustainable development which affect 20 to 300 million peoples each year (Hirabayashi & Kanae, 2009). In recent decades, many studies have been carried out on floods which have mainly approached to flood risk management. Flood inundation models are defined as the tools which could simulate the rivers hydraulic and also occurred floods in flood plains (Horrit, 2007). In other words, flood inundation models are useful tools for flood plain management. This ability in flood prediction, and also flood damage reduction by protecting of near river land use, improving the knowledge of indigenous people of flood plain, and preventing the construction in banned area of flood plain is very useful (Di Baldassarre, 2010). In this study the risk of flood occurring for different return period along 72 Kilometer in Qaraso River have been investigated.

    Materials and Methods

    This research is based on filed studies and 1:2000 scale topographic maps that provided by Ardabil regional water authority. The 1:100000 scale geological maps, satellite imagery such as IRS and Google Earth and also hydrometric data of Dostbaglo and Arbab Kandi hydrometric station, considered as essential data. The HEC-RAS model could calculate the water surface profile in stable flow gradual variable in rivers and artificial channels in the subcritical, supercritical and complex regimes. The calculation of water surface profile carried out from one cross section to other cross, step by step, solving energy equation in standard way.

    Results and Discussion

    In this study in order to estimate the frequency distribution of floods we used Pearson Type III distribution in logarithm base 10, which provided by USA federal organizations of rivers reconstruction. Then flood peak discharges with different return period and its probability of occurrence has been calculated for important hydrometric station namely: Dostbaglo and Arbab kandi. According to the flood-prone zonation map, we observed the maximum wide of flood-prone area in reach2 to reach4 of river (from Qadirlo Village to Lalganj Village) in different period. In these reaches the width of flood-prone area in 25 years return period is about 500 meter on average. In first and some parts of reach6 and reach7, due to narrowing of channel and some obstacle the wide of flood-prone area was decreased and instead the water depth has been increased. Regarding to the placement of the Qadirlo, Kangarlo, Agh¬ Darag and Dostbaglo villages in the margin of the Qaraso River, the flood zonation in this rivers should be considered. The main landuse of Qaraso riparian is assigned to agriculture and orchards. By overlay the flood zonation maps with satellite imagery we observed that the main portion of this agriculture lands, has been located in the river bed and riparian zone (according to 25 years return period), are at risk of flooding. This could lead to heavy damage for farmers. For example, the flood events with 25 years return period, affected about 1085 hectare of farmland and orchard that located beside Qaraso River and lead to heavy damages.

    Conclusions

    Regarding to notable encroachment by farmers in the Qaraso river bed, the Flood risk is very important. The flood-zoning of Qaraso River shows that wide part of farmlands and orchards and also part of the facility located around the Qaraso River (nearby the village of kangarlo) have been exposed to floods with 25 years return period. Therefore, according to article 10 of regulation of bed and riparian of rivers the regional water authority of Ardabil should determine the condition of this high risk area. Accordingly, the floodplain management should be considered as an important and essential issues.

    Keywords: Flood zonation, Return period, HEC-RAS model, Floodplain, Qaraso River
  • Monireh Rayati Shavvazi, Hamid Reza Ghafarian Malamiri, Adel Sepehr, Amir Karam * Pages 17-36
    Introduction
    Desertification is associated with the process of destroying and demolishing the natural ecosystems in ultra-arid, arid, semi-humid arid regions, leading to reduced biomass production and the appearance of soil degradation or erosion effects. More than 80% of Iran is located in ultra-arid, arid, semi-humid arid regions of the country with fragile ecological conditions and are influenced by desertification phenomenon.
    In order to study the desertification and to analyze the trend of its changes, a wide range of spatial and temporal information such as geomorphology and land-use are needed. In fact, analyzing their changes is the process of identifying differences in the status of an object or a phenomenon by observing it at different times, which provides a basis for better understanding of human relationships and interactions with natural phenomena for managing and making better use of resources. In environmental management, the most common contributions of geomorphologists are to provide a map of landscapes with emphasis on its selected features, to understand the nature and causes of landscape changes, and to organize them according to trend predictions during the formation processes and the transformation of landforms. Human's specific use of territory as land use is also an important consideration in land tenure assessment. These applications change at time intervals. In arid and semi-arid regions, these changes usually lead to increased desertification.
    The identification of deserts' landforms and land-use, their classification and mapping at various time intervals are considered as a method for change detection in these areas. Today, using remote sensing (RS) instead of the visual interpretation to identify landforms and land use and their change detection is a necessity. One of the steps in identification of change detection is the classification of remote sensing data. There are various methods for the classification of satellite images. These methods can be used for separation of different geomorphological landforms and land-uses and their variations. Each method has its own advantages and limitations. The choice of the research method in geomorphology depends on the purpose of the study and the available data. Today, the use of satellite data and remote sensing techniques are considered as a modern method in geomorphological studies.
    The most common classification methods can be referred to as the maximum likelihood classification. Other classification methods such as the minimum distance, Mahalanobis distance, and neural network have attracted much attention. The main objective of this study is to investigate and analyze the temporal variations of geomorphologic landforms and land-use in desertification part of Yazd-Ardakan Plain. For this purpose, time series satellite observations of Landsat sensor were used from 1986 to 2016 (over 30 years).
    Materials and Methods
    In this research, a part of the Ardakaan-Yazd basin is considered for desertification analysis due to the issues and problems related to land destruction and the critical focus of wind erosion. This district, according to the latest political divisions, includes central zone and Khezerabad zone of Sadoogh county in Yazd. The area of the study area is 1563.11 km2.
    The research method in this study is analytical survey. To study the changes of desert's landforms and land uses, two satellite imageries of TM and OLI of Landsat satellite of 1987 and 2016 were used. First, the radiometric and atmospheric corrections was performed using Flaash algorithm, and then the geomorphological landforms and land use were introduced and the training samples were selected by field observations, topography and geomorphology maps, and Google Earth images. To classify the landforms and land use, the supervised classification of maximum likelihood algorithm was used. Then, the accuracy of classified maps was evaluated using the overall accuracy and the Kappa coefficient metrics. Finally, to evaluate the changes of landforms and land-uses, the post classification method was used. To analyze the database, ENVI 5.3, ArcGIS 10.4.1 and Excel 2013 software were used.
    Results and Discussion
    In the present study, 15 landforms were identified in the study area with regard to field observations, available resources and geomorphologic map of Yazd-Ardakan plain.
    Totally, 15 landforms were identified in the study area, including Alluvial Fan, Glacis Pediment Plain, Clay Pan, Glacis Dennoyage Plain, Inselberg, Glacis Epandage Plain, Kalut, Erg (barchans, longitudinal dunes, barchanoid), hills, mountains, Salt Dome, Sebkha and Sand Sheet. In addition, 8 land-use classes were identified in the study area. After the image correction, the geomorphological and land use maps were prepared. Finally, to investigate the nature of the changes, the comparison method of post classification was used, which was applied on maximum likelihood algorithm. Then, the changes of landforms were calculated in terms of its area and percentage. The results showed that the dominant class was the Glacis Epandage Plain in the both satellite images of 1987 and 2016. Then, hills with 17/58 percent of the total area are ranked as the highest area in 1987, while this class had downward trend with 11/58 percent in 2016. In 1987, Barkhan class had the lowest area with 0/17 percent, whereas this class had downward trend with 0/11 percent in 2016.
    Changes in land use classes over a 30-year period in terms of area and percentage indicate that the predominant class in 1987 was the low-density rangelands of the range of 25-5%, which, remains the prevailing class in this year even with the decrease in the area of this class in 2016.
    The saline lands with 22312.63 hectares of the entire region are of the next order of the most area in 1987 but have the decreasing process to 1.14% in 2016. In 1987, the urban class occupied 0.46% of study area with a growth rate of 2.33% by 2016. The construction of forested trees for deforestation also shows a growth rate of 15.36% over 30 years.
    Conclusions
    The results of the landforms and land use classification showed that the maximum likelihood algorithm offers a detailed classification method. The area and the percentage of landforms and land use changes over 30 years showed that landforms such as Barchan, Clay Pan, Longitudinal Dunes, Barchanoid and Kalut had a downward trend, because they were located in the context of the development of the city. The results showed that Sabkha area has followed a downward trend over 30 years. The comparison of our results with the results of previous studies showed that the increase of wells in Yazd-Ardakan plain has helped cultivate the large areas of saline lands. Therefore, the natural and human factors were involved in changing the desert landform and land use in the study area.
    It should be noted that this study shows that the separation and analysis of the landform variations, such as the Salt Dome and Inselberg created in long time intervals, cannot be easily accomplished using the maximum likelihood algorithm. Because they were of ascendant trend during 30 years according to the outcomes, and this is because of similarity of their adjacent spectral reflections in which case the pixels of these landforms have been replaced by more pixels. However, according to the results, separating and analyzing the changes of the sandy hills is possible with the maximum similarity algorithm method during 30 years (from 1986 to 2016). In general, the results of this research were in the line of the previous studies that confirm above statement.
    Keywords: Spatial-temporal changes, Landform, Land use, Desertification, Maximum likelihood, Yazd-Ardakan Plain
  • Gholam Reza Maghami Moghim *, Amin Navidtalab Pages 37-55
    Introduction
    Salt diapirism is a process that the overlaying rocks are impregnated with upward moving evaporites, and produce highlands. Due to their importance in human life and activities, these phenomena are of interest to researchers. The studied area has been affected by salt diapirism. Landforms made by these activities have changed the topography of the area. The associated topographic features, in turn, play an important role in human activities such as Tehran – Mashhad railway. Due to the nature of salt diapirism and fast changes, this phenomenon can lead to sever problems for human societies. Ignorance of salt diapirism in civil projects such as road and railway constructions can produce irrecoverable costs. Due to the importance of salt diapirism in human life, these phenomena have been vastly studied.
    Studies on diapirism have been carried out in Southern Iran (Arian & Nowruzpour, 2015; Talbot, 1979), Southern Spain (Gattirose, 2010), and the Netherlands (Harding & Haus, 2015). These studies in Southern Iran mostly dealt with the fundamentals and they did not investigate their applications.
    Due to their even topographies and geographical settings, the areas affected by the salt diapirism have been used for railway network. However, the risks related to these areas have not been considered by the national Disaster Management Organization and the authorities.
    The Tehran–Shahrud–Mashhad railway in the study area between Shahrud and Bakran stations could be affected by diapirism and the related risks. Through the present study, field observations and remote sensing approach were integrated to evaluate diapirism, and the results can be applied for preventing the railway-related hazards.
    Materials and Methods
    The study area is located in Shahrud County, Semnan Province between the coordinates of N36˚27ˊ - N36˚31ˊ and E55˚32ˊ - E55˚38ˊ. Shahrud – Jilan railway and Meyami – Jilan road are the access ways to the study area.
    Topographic and geological maps along with field observations of different salt diapirism morphologies were used in this study. In addition, digital elevation model (DEM) data of 30 m special resolution from shuttle radar topography mission (SRTM) were used to produce digital layers. Field and remote sensing data were investigated using the indexing natural hazards (INH) method. In this method, salt morphologies in the studied area were classified according to the distance from railway, the production of secondary phenomena, reoccurrence, predictability, and structural geology. According to field measurements and library research, they were then ranked from 1 to 3 in terms of the danger to the railway. Based on the gathered information, the processes and phenomena were weighed to understand the role of each one in producing hazards for the railway. All the maps were produced by ArcGIS.
    Results and Discussion
    3-1- Mechanisms of Salt Diapirism
    Tectonic activism has been the most important mechanism in the formation of salt diapirs. Structural deformations in the studied area is under the control of tectonic activities between the Central Iran and Alborz structural zones. The encounter of these two structural zones has provided an appropriate setting for the accumulation of evaporates. The subsequent folding has resulted in the formation of Jilan Anticline and Jilan–Farashian fault. These deformations led to the impregnation of evaporates into the overlaying beds and formed salt domes. Landform formation due to upcoming salt is called salt tectonics. Additionally, buried salts in Pre-Miocene sediments changed their volume and pushed the overlaying strata upward and formed salt domes. Erosion had an important role in salt movements. Sediment overlaying the salts (gravel, sand, and marls) were removed by erosion and let these salts to emerge on surface. Salt dissolution in water had the greatest effect after the aforesaid events. Two forces oppose the salt diapirism which their removal by geological and anthropogenic processes can activate salt diapirism. The construction of the Miamey–Jilan road crossing the middle of the anticline had a crucial role in erosion and outcrop of salt strata. The emergence of salt strata in the center on the anticline shows that the thickness of salt reaches to more than 40 to 50 m in the uplifted area. After the structural processes, the dissolution of salt in water has the most important role in landform formation.
    The dissolution potential of salt rocks is more than other rocks. However, the amount of dissolution depends on the temperature. The higher temperature is, the more dissolution there is. Considering that the temperature of the studied area in warm seasons reaches to 27˚ C, this can increase the rate of dissolution by increasing the water temperature.
    3-2- Effects of Salt Diapirism on the Railway
    One of the most effective landscapes of salt diapirism in the region is the Jilan Anticline, which was affected by the Meyami – Farashian fault. Perhaps, activism of Meyami in the South and Jilan–Farashian in the North had an important role in salt diapirism. Continuous pressure by these faults led to the instability of the northern flank of the anticline. Considering that the Tehran–Mashhad railway passes the North of the Anticline, it is possible that these tectonic activities result in the collapse of sinkholes and ground subsidence beneath the railway. Salt domes are other features affecting the railway by uplifting in the area. Salt karstification also can affect the area. Sinkholes are among the most typical features of salt karstification. As sinkholes are formed rapidly, the existence of the buried sinkholes under the railway is not entirely unexpected considering their trends. Steep-sided, deep sinkholes (karstic wells) are considered as possible threats for the railway because they are covered. Salt ponorscause underground dissolution by draining runoffs into the earth. The existence of more than 50 ponors at the neighboring of the railway indicate high potential risks. Salt polje have formed in the southern part of the studied region. They might be used as substrate for constructions because of the appropriate angle of slope. However, owing to the possible dissolution under the polje, they can produce high risks. Salt glaciers along both sides of the railway can be hydrated in wet seasons and produce an unstable substrate. Salt springs are other karstic features which play a key role in the transport of the salt from underground to the surface. They could be a source of water for animals, which increases the risk of running into the trains. Salt valleys are hydrologic morphologies that during the wet seasons are flooded by deluges and can destroy railway and its related structures.
    Salt cones are also present in the area and their effectiveness depends on their shapes. Although the shape of salt cones indicates their activeness, they can be considered as stable morphologies due to salt alluvium accumulation. Salt cauliflowers are the features formed in the salt formation. Their accumulation alongside the railway can produce unstable substrates by receiving water. Salt polygons can make risks by watering/dewatering and the consequent expansion/shrinkage.
    Due to the presence of salt rocks, gypsum, marls, and clays with intercalations of salt, the strata can be ascribed to the Pre-Miocene which has been folded lately. The exposure of salt rocks has produced the landform of domes, valleys, sinkholes, caves, ponors, rivers, springs, polje, polygons, and the alluvial fans affecting the Tehran–Mashhad railway.
    Conclusions
    Through a quantitative analysis using the application of IHN, it is proved that sinkholes and wells with 1.37 and 1.5 coefficients, respectively, are among the most hazardous features, and their destructive effects on the railway can be visible as collapsing and sliding. Ponors and salt rivers with the coefficients of 1.62 and 1.75, respectively, are classified as high risk features by producing underground caves and surficial floods. Glaciers, polygons, and domes with the coefficient of 2, the Jilan Anticline and salt cones with the coefficient of 2.42, and valleys and springs with the coefficient of 2.14 have moderate risks. Salt polje with the coefficient of 2.57 has the lowest risk for the railway.
    Keywords: Salt diapirism, Railway, Salt karst, Jilan Anticline
  • Hamid Ebrahimi *, Aliakbar Rasuly, Davoud Mokhtari Pages 57-73
    Introduction
    Fire plays a major role in shaping the structure of many terrestrial ecosystems and influences their functionality. With East Azerbaijan Province experiencing one of the most severe droughts over the past few years, the average size and extent of burned area had increased intensively in this region, which is significantly posing threats to the wildland, people, property, and destroying environmental infrastructure. In order to accomplish an in time effective and preventive management and also prior to fire occurrences in forest and rangeland, it was essential to identifying and classifying the susceptible areas and factors influencing on fire occurrences. Generally, the lack of knowledge about regional conditions, which has major influence on the expansion of fire occurrence and causing serious damage to environmental area, infrastructure and property, animal life and plants (Jaiswal et al, 2001 1). Therefore, generating of fire susceptibility maps and analyzing its driving factors may have a great impact on reducing and preventing the deforestation and desertification in environmental area (dong et al, 2005: 169), also it will support and assist the activities of managers and planners in forest management for planning and implantation of an early warning system. In this manner, understanding the spatial distribution of fire ignitions and learning about the key drivers behind this distribution is mostly based on the analysis of historical fire locations. Detailed information about the changes of spatial distribution of fire dangers will provides valuable guidance in the direction of forecasting the trends of environmental dangers for the government and protection agencies. Moreover, it would be very useful as a complementary approaches to fire or wildfire management. Various approaches have been applied to modeling wildfire susceptibility, including different techniques, some authors concluded that machine learning algorithms, like maximum entropy (MaxEnt), performed with high accuracy for modeling wildfire susceptibility. In this regard by using an approach based on a machine learning algorithms called the maximum entropy (MaxEnt) with correct and well-organized data in the context of geographic information system (GIS), it is possible to achieve better and more understanding of the changes in the spatial distribution in fire dangers and affecting factors. In the current study, by using of fire event data from a 9-year period, wide variety of environmental variables and MaxEnt approach, an attempt was made for investigation in fire danger and its influencing factors in forest and rangeland of East Azerbaijan province over a 9-year period.
    Materials and Methods
    The present study area is East Azerbaijan province in Northwestern Iran, which lie between latitudes 36° to 39° N and longitudes 45° to 48° E and extends over 47,000 km2, with a wide variety of vegetation types, topographical and climatic conditions. The East Azerbaijan province environment is highly diverse in terms of climate, geology and topographic characteristics which lead to different levels of susceptibility to fire. The climate in the study area based on the De Martonne aridity index is semi-arid, average annual precipitation and temperature are 315.2 mm and 10.2 °C, respectively, and elevation ranges from 160 to 4811 m above sea level.
    Three phase comprising in the methodology of this research; the first phase applies the several methods such as image processing techniques, GIS analysis, and spatial interpolation methods for producing the dependent and independent datasets. The second phase, data of fire occurrences between 2006 and 2015 associated with a range of environmental and anthropogenic independent variables in three period (2006-2008, 2009-2011 & 2012-2015), jackknife test was used to find out the main driving factors in the spatio-temporal distribution of fire and wildfire. The third and last phase includes analysis of changes in fire danger and its driving factors. Data was collected from various sources including satellite imageries, and metrological data. Fire occurrences and locations were derived from MODIS (Moderate-Resolution Imaging Spectero Radiometer) fire product, historical record of environmental protection agency, and field checking. The Collection 5, Level 3, 8-day MODIS Terra and Aqua active fire product (MOD14A1 & MYD14A1) was used during this study. In the data preparation phase, ASTER Global-DEM with 28.5 meter spatial resolution was used to generate maps of elevation, slope and aspect by using ArcGIS software. Climate maps (max and mean temperature, and precipitation) were created through the interpolation of data gathered by several meteorological stations in the region. A detailed land use/land cover map derived from LANDSAT 8 satellite images, using multi-layer perceptron (MLP) neural network method as a wildly used image classification approach. Then, with kernel density and Euclidean distance functions, anthropogenic variables were created. Eventually, map of Normalized Difference Vegetation Index (NDVI) was derived from MODIS satellite imagery. Maximum Entropy (MaxEnt) is a presence-only machine learning algorithm that iteratively contrasts environmental predictor values at occurrence locations with those of a large background sample taken across the study area. The principle of MaxEnt is to estimate the probability distribution of maximum entropy, which is below a collection of constraints (environmental and anthropogenic conditions), the most spread-out or closest to uniform. It is a sophisticated approach to modeling the probability distribution from the n-dimensional environmental space using occurrence locations data and iteratively evaluates the contrasts between the values of those occurrences and those of a background consisting of the mean occurrence over the entire study area, as sampled from a large number of points. By applying this algorithm, the most uniform distribution will be recognized and selected from several possible distributions, moreover it can specify a per-pixel susceptibility to wildfire occurrence which might be used as an essential tool for environmental hazard management in forest and rangeland.
    Results and Discussion
    It should be noted that the MaxEnt software was used to analysis the fire susceptibility. The main outputs of this model are; prediction of fire danger in study area, Receiver Operating Characteristic curve as an indicator for accuracy assessment and jackknife test to assess the significance or relatively importance of each independent variable in model result in each period. The process of implementation models for three 3-year period have been done by using the fire occurrences data as the dependent variable and 12 anthropogenic and environmental factor as the independent variables. Assessment of the changes at different areas in terms of fire susceptibility represented upward trend in fire danger, increasing the areas in high-risk zones and extensive changes in the factors influencing the fire occurrence. According to the results most extent of changes about decreasing the areas of zones with very low risk and increasing the area of zones with very high risk and medium risk. Based on the result of accuracy assessment by using Area Under Curve (AUC), which was calculated from Receiver Operating Characteristic (ROC), our analysis indicated the maximum entropy as machine learning algorithm were efficient predictor (AUC =0.91, 0.828, 0.839) for wildfire susceptibility assessment in East Azerbaijan province in three different time period.
    Conclusions
    The machine learning algorithm MaxEnt was successfully applied to analyzing forest fire susceptibility assessment in East Azerbaijan province to demonstration areas with higher fire susceptibility and analyzing its driving factors over the times. Due to the high accuracy of the suggested model (MaxEnt) which has been utilized in the study for 3- period (2006-2008, 2009-2011 and 2012-2014) and also the assessment of the previous studies, this model could considered as a proper approach to evaluating and modeling fire danger and its affecting factors. The results of this study will help to determinate and evaluate fire management objectives. Considering limited financial and human resources to suppress fires in the East Azerbaijan province the concentration on very susceptibility areas could be a way to encounter these challenges. The results can be used for preventive actions and additionally for making more scientific and appropriate decisions. Investigate the changes of fire dangers in forest and rangeland of East Azerbaijan and its upward trend, reveals the requirement for more attention to this issue and also for planning the proper strategies and activities. On the other side increasing in the impact of human factors on fire occurrences in recent years, demand the necessity for cultural proceeding, raise of public awareness as well as taking advantage of the general public potential in the field of preventive activities.
    Keywords: Wildfire, Susceptibility analysis, MaxEnt approach, Forest, rangeland, East Azerbaijan Province
  • Hamidreza Pourghasemi, Sahar Goudarzi, Ali Talebi * Pages 75-96
    Introduction

    Landslide is introduced as one of the most important natural dangers in mountainous regions and induces heavy life and financial damages in life of mankind (Bui et al, 2012). Landslides in Iran are taken into account as one of the most common natural dangers, too and annually, induce many life and financial damages to the country and induces high cost to rebuild damaged regions on budget of the country (Zare et al, 2011). In view of undesired effect that this phenomenon has on social, economical and natural systems, knowing talented regions of slide is very necessary in level of the country. In view of dominant territory on the region, geology, being mountainous of Sardarabad watershed, non- principle building of roads and existence of 15 villages having inhabitants, Sardarabad watershed is such as talented watersheds of landslide and in view of landslides than other natural disasters like flood, volcano, and earthquake have capability of more management, so preparing map of zoning of landslide of the region is taken into account as one of important factors and tools in management and control of landslide danger. Using results of this research can prevent to further occur landslide and damage due to it in the region. Goal of the present research is to zone sensitivity of landslide by using adaptive neuro-fuzzy inference system with structure of fuzzy clustering inference system in Sardarabad watershed of Lorestan province.

    Materials and Methods

    The study area is the Sardarbad watershed in Khoram-Abad city, Lorestan Province. In order to carry out this research, first maps and basic images were obtained from the Natural Resources Office of Lorestan province. Spacing spots were recorded using aerial photographs (scale of 1: 20000) and field observations (using GPS) and entered the ArcGIS 10.2 software to provide land slide mapping in the area. Information layers for slope, altitude, gradient, distance from the road, distance from fault, distance from the waterway, rainfall, lithology and land use (as the affecting factors for landslide occurrence) were provided based on the basic maps (topography, geology and satellite imagery). The land use information layer was prepared from the Office of Natural Resources and Watershed of Lorestan Province. The geologic map and the distance from the fault are also provided by the geological map of the region (scale of 1: 100,000). The waterway layer was extracted from the topographic map of the study area. The gradient map was provided by topography map (1: 25000) and its digitizing was done in ArcGIS10.2 environment in three classes (concave, flat and convex).
    In order to determine the amount of rainfall in the basin, all stations have been used with 30 years data. Due to the importance of rainfall in the occurrence of landslide, the rainfall map was prepared using rainfall data from existing stations from 1981 to 2011. In the Sardarabad watershed, the land use map was extracted from the ETM satellite data and completed by field operations (according to the report of the Natural Resources Department of Lorestan Province). In total, 109 sliding positions were identified using the database of the Office of Natural Resources and Watershed Management of the province, Google Earth images and field observations in the study area. After determining the effective factors, the mentioned maps and providing the data bank, landslide susceptibility map was obtained using the Anfis Model in ArcGIS (SAGA-GIS).

    Results and Discussion

    Based on the frequency ratio equation, the obtained weights were applied in 10 effective factors in landslide occurrence. Finally, using this equation, the level of correlation between the landslides and the effective factors (with a cell size of 30 meters) were obtained and was considered as the input weight of the Anfis model. After providing the weighted maps based on the model's equations, the landslide sensitivity map was obtained.
    Finally, the landslide sensitivity map was obtained from the ANFIS method. Based on the natural fractures, landslide sensitivity map was classified to four classes (low, moderate, high sensitivity, Too much). A rock curve was used to obtain a suitable regional model for Sardarabad watershed. As the points are closer to the top and left (closer to 1), the model result is more appropriate and the predictions of model is closer to reality (Yesilnacar, 2005).
    Overall, the division of 0.9-0.1 is excellent, 0.9-0.8, very good; 0.8-0.7, good; 0.6-0.7, moderate and 0.6-0.5; weak; (Zhu et al., 2009; Yesilnacar,2005). For this purpose, among the 109 identified landslides, 32 cases have been prepared for the model evaluation. According to Rock's results, the surface area under the curve of the study area using the adaptive neuro-fuzzy inference system is 89.11%, which indicates that the model lies in a very good class.

    Conclusions

    In this study, a nero-fuzzy model was used for landslide hazard zonation. The results of the Roc-Curve assessment in gaussian membership function showed that the surface under the curve is equal to 0.891. This means that the model sensitivity (89.1%) is correct. Also, due to the fact that the surface area under the curve ranged from 0.8 to 0.9, the accuracy of the model was in very good class. Overall, the study area has a high potential for landslide occurrence and without preventing and managing, these landslides annually cause damage to the road, residential areas and other resources in the region.
    Geological factors, geomorphologic characteristics and the network of the canals are constant, and the only way to prevent their damage is bypassing these areas and not provoking these areas. Road factors and land use are one of the most effective factors in the occurrence of landslides in the area. They have more management ability. By constructing a road based on the conditions of the ecosystem and preventing the construction of unconventional roads and proper use in these areas, it is possible to prevent from their movement in the study area. The obtained map showed that the adaptive neuro-fuzzy inference system model has a high performance to provide the landslide sensitivity map.

    Keywords: ANFIS, Land slide, Roc Curve, Sardarabad Watershed
  • Hassan Oroji, Hamid Zamani, Zahra Arabi * Pages 97-114
    Introduction
    Tourism, as the largest and fast growing economic activity in many countries around the world, is an important sector of the world economy (Grillakis et al, 2015). This economic activity strongly influenced by many factors, including culture, economy, environmental potentials and climate of the places that host the activity. However, climate as an important environmental component of a given region profoundly impacts tourism because it is very much dependent on climate conditions. Undoubtedly, a comfortable climate for recreational activities in any given destination is the main factor in tourist attraction, but an unsatisfactory climate or adverse weather conditions substantially reduce the number of tourists. in the past few decades, climatic factors played an important role in the process and trends of world tourism and, the tourism planners and operators, indigenous communities of tourism destinations and tourists, and all of the factors and components of the tourism system have a special focus at the climate factor at their tourism decisions. In this prospective Iran, as a country with a diverse climate is considered at tourism decision making. In recent years, climate tourism researches is based on survey data and measuring tourist’s satisfaction about climatic conditions because of differences between tourism destinations and variety cultural, economic, political and social conditions. Iran country is one of the most country in the world based on climate and tourism capabilities. Iran’s south coasts has high potentials about tourism and climate tourism. The paper try to survey climate tourism based on surveying data and tourists interviews and presenting improvement in tourism climate indexes.
    Materials and Methods
    In order to surveying tourism climate in Qeshm Island, it is used tourism climate indexes involved CIT, PET and PMV indexes. In order to evaluate the climatological condition of Qeshm district for tourism, the TCI, PMV, and CIT climatic indices were computed for Qeshm station as the representative of the coastal areas of southeastern Iran. These three indices were selected as they consider the climatic and environmental conditions, the human thermal condition and the degree of satisfaction of the tourists previously visited the target area CIT rates the climate resource for activities that are highly climate/weather sensitive, specifically, beach “sun, sea and sand” (3S) holidays. CIT integrates thermal (T), aesthetic (A) and physical (P) facets of weather, which are combined in a weather typology matrix to determine a climate satisfaction rating that ranges from very poor (1 = unacceptable) to very good (7 = optimal). Parameter A refers to sky condition and P to rain or high wind. T is the body-atmosphere energy balance that integrates the environmental and physiological thermal variables, such as solar heat load, heat loss by convection (wind) and by evaporation (sweating), long wave radiation exchange and metabolic heat (activity level). The second index used in this research is the predicted mean vote index (PMV) developed by Fanger (1972) to defining the thermal comfort of the environment, using the heat balance equations and empirical studies of skin temperature. The PMV and the predicted percentage dissatisfied (PPD) index were developed to help air-conditioning engineers to create a thermally comfortable indoor climateThe Predicted Mean Vote (PMV) model stands among the most recognized thermal comfort models. It was developed using principles of heat balance and experimental data collected in a controlled climate chamber under steady state conditions. The adaptive model, on the other hand, was developed based on hundreds of field studies with the idea that occupants dynamically interact with their environment. Occupants control their thermal environment by means of clothing, operable windows, fans, personal heaters, and sun shades. The PMV model can be applied to air conditioned buildings, while the adaptive model can be generally applied only to buildings where no mechanical systems have been installed. There is no consensus about which comfort model should be applied for buildings that are partially air conditioned spatially or temporally. The Munich energy balance model for individuals is one of the thermo physiological heat balance models. It is the basis for the calculation of the physiologically equivalent temperature (PET). Data period is 2003-2013 in Qeshm coastal synoptic station.
    One of the largest islands in the world, Qeshm boasts numerous natural, historical, religious and trade attractions. The beautiful nature of Qeshm has not only made the island an ideal vacation spot, but also an intriguing place for academic research. Qeshm Island is located a few kilometers off the southern coast of Iran (Persian Gulf), opposite the port cities of Bandar Abbas and Bandar Khamir. The island, at its widest point, located near the center of the island, spans 40 kilometers.
    Results and Discussion
    The results shows important points. Although tourism climate in Qeshm station is suitable in cold months and night hours but when tourism climate in Qeshm assess by CIT index, all of the months in a long year and all of the daily hours (except daily hours in months of summer) is suitable and acceptable that it is incompatible with the Qeshm island condition. There are many differences between tourism destinations and between tourists according to natural, human, cultural and social condition. Therefore. The CIT index is improved by the paper. In order to improvement, PMV index is compound with data of tourism satisfactions in completing questionnaire from tourist in Qesh coasts. PMV multiplied with tourism data. New values is from -28 to 28. Values -2 to 2 is very good climate condition for tourism and values -6 to 6 is acceptable. Results of the improvement CIT shows that Qeshm Island is unsuitable in six months (from May to October) in year and all of the daily night hours in the same period.
    Conclusions
    This paper try to esurveying tourism climate index in differences condition and different places and destinations and involving tourism satisfaction data in results of tourism climate. It is concluded CIT index is presented in spatial condition and it shouldn’t exclusively in all of the world. Because, tourists has different emotions and interests and perceived climate also is variety. Tourists is different with resident people. New and improved CIT shows actual results and compatibles with space conditions.
    Keywords: tourism climate, CIT index, Qeshm Islan
  • Abbasali Arvin * Pages 115-129
    Introduction
    Urban heat island refers to an area where the temperature is higher than of the surrounding environment. It is referred to as an island since the temperature of a point or an area of the earth's surface (the city) is more than of the surrounding environment, which mostly has, a homogenous and uniform temperature. Therefore, this island, which can be separated and distinguished from the surrounding environment of the city, is named the city of heat island. Urban heat island can be due to growing population and its concentration in the urban centers, and consequently the increase in air pollution. Changes in land use can be regarded as one of the underlying causes of the occurrence of urban heat island. For example, using satellite images to study the heat island in the city of Mashhad, by Mousavi Bayeghi et al. (2012) showed that along with the land use change from the garden level to the city one, there has been a rise in the temperature. Frequent pollution in the city of Isfahan in recent years has led to the development of some hypotheses assuming some relationship between urban heat island and pollution. In this regard, the growing population density and the vertical expansion of the city, as well as urban development, have resulted in the development of the idea that the study of urban heat island in relation to air pollution can be very important as it can help cope with and decrease the degree of urban heat island. With this objective in mind, this study is designed to address this important concern.
    The growing intensity of the thermal island due to air pollution in addition to the undesirable effects on human health can seriously damage the valuable historical works in the popular tourist city of Isfahan. It is hoped that the results of this research could help reduce the effects of the thermal island, leading to the development a better living environment in the city of Isfahan accordingly. Methods based on Satellite images can be regarded as one of the best ones for studying the thermal island; in fact, such methods have been used in many studies inside and outside the country. In this research, the thermal island in the city of Isfahan has also been analyzed using satellite imagery.
    Materials and Methods
    In order to study urban heat island in the city of Isfahan, a series of landsat 8 satellite images with good resolution were used. This satellite conducts imaging through 11 spectral bands. The bands 1 to 9, which are known as OLI, carry out imaging in color and NIR spectra. The bands 10 and 11 are well-known as TIRS thermal bands. They do imaging within long infrared waves. In this study, the bands 4, representing red, and 5, representing the near-infrared, and the thermal bands 10 and 11 were used to study the urban island in the city of Isfahan. The data related to AQI air quality index was used to check days with air pollution. Due to the restrictions over the passage of satellite within a period of 16 days over the city of Isfahan, the limited number of days with extremely high pollution in the city, and the non-conformity between polluted days and the time of satellite passage, images of three days representing the very unhealthy (the red condition), unhealthy (the orange condition), and healthy (yellow condition) air were thus used. In this study, Subrino Split-Window algorithm was used as the technique to calculate the Earth's surface temperature. This method is based on the calculation of brightness temperature of the bands 10 and 11 as well as the vegetation index of the bands 4 and 5. For this purpose, Arc_GIS10.3 software was used to compute the Earth's surface temperature and the air temperature of the city. ENVI software was also used for the atmospheric correction.
    Results and Discussion
    Isfahan, due to climatic conditions and a flat topography, has a relatively quiet atmosphere throughout the year. Although Mount Soffeh is located in the south-west of the city, this mountain can only help reduce the speed of westward winds over the city as it is a single peak with a low height. In addition, the vertical expansion of buildings in all parts of the city causes the wind speed to be slow due to the increased friction. High buildings with greater height than the other points, especially in the western part of Isfahan, have led to the considerable reduction of wind speed, which is an important parameter. On the other hand, population growth and its concentration in the central part of the city have increased the intensity of urban heat island. To address the possible relationship between air pollution and urban heat island, the date of January 22nd, 2014 was chosen for investigation. On this day, the temperature calculated from satellite images of the city was within the range of 3 and 17 degrees Celsius. In general, the temperature fluctuated between 5 and 9 ° C in most parts of the city, and the 7° C isotherm bypassed most parts of the city.
    The correlation coefficient between vegetation index (NDVI) and land surface temperature, LST, was equal to the 0/37064, which was significant at the confidence level of 99%. Given that the urban heat island is based on urban atmospheric temperature, not the temperature of emitting or reflecting surfaces, some empirical relationships were used to convert surface temperature to air temperature. Accordingly, it was found that the air temperature in the city fluctuated between +5.5 and -1.8 ° C on January 22nd, 2014.
    The comparison of the city thermal island map with the map of pollution distribution confirmed the increase in the city temperature as a result of urban air pollution.
    That is, the highest concentration of pollution in the East and North East of related to the areas with the higher air temperature. The observed maximum temperature shown by the color red in the map was 13.8 degrees and this was 10.6 degrees in the suburbs. Temperature difference between the city heat-island and suburban areas on this days reached to 3.2 degrees Celsius.
    The highest rates of pollution were observed in the stations located in the Eastern Isfahan, including the Ahmadabad SQ and Kharazi Highway. Correlation analysis between the earth's surface temperature map and the map of the distribution of air quality index in the city of Isfahan showed a correlation coefficient of 0.242 at 99% confidence level on January 22nd, 2014. On this day, air pollution AQI index was between 117 to 169, and the temperature ranged from 8.5 to 13.7 degrees Celsius.
    Conclusions
    The city of Isfahan, due to stable climatic conditions at most times of the year and the spread of pollution, is one of the most polluted cities in Iran. The increased intensity of thermal island is one consequence of this phenomenon. In this study, Landsat 8 satellite images with a high resolution were used to estimate the surface temperature of the Earth. The temperature calculated by the model was compared with the soil temperature at the meteorological stations. A slight difference between the temperature in soil at the depth of 5 centimeters and the LST obtained through satellite images, which ranged from a maximum of 6 to a minimum of 1.8, showed that the Subrino's Split Window method could be suitable for estimating the surface temperature of the earth. Finally, the urban heat island in the city of Isfahan was obtained based on the statistical relationships between the land surface temperature (LST) and the air temperature. The analysis of topographic profile related to thermal island temperature showed the promotion of the thermal island in the city as compared with the surrounding area. That is, the temperature inside the city was 7.3 degrees and 9.5 degrees Celsius warmer than the surrounding area respectively, which could show the city's urban heat island clearly. The difference between the temperature of the city's thermal island and the city's surrounding temperature was higher at the time of the maximum pollution. The comparison of the temperature maps of Isfahan with the pollution distribution maps revealed the maximum correlation between temperature and the pollutant areas. The correlation coefficient between the pollution distribution map and the urban temperature map was positive and significant. In more polluted days, the linear relationship between the pollution increase and urban air temperature increase was stronger. As a result of the increased air pollution, the intensity of the thermal island of the city was aggravated. The study of air pollution distribution in the city of Isfahan showed that the eastern regions had more contamination. This was influenced by the urban topography. This is because the southern and western parts of Isfahan are at a higher elevation due to the presence of Mount Soffeh, and the pollution due to mass weight tends to subside in the lower northern and eastern regions of Isfahan. On the other hand, pollution is more concentrated in the eastern regions of the city due to the slow prevailing western winds. The comparison of the thermal map of the thermal Island in the city of Isfahan to the pollution distribution map confirmed the effect of pollution on the increase of urban air temperature. Therefore, the most pollution was concentrated in the eastern and northeastern Isfahan, which were the areas with the higher air temperature. The observed maximum temperature reached to 13.8 degrees, whereas it was 10.6 degrees in the suburbs of Isfahan.
    Keywords: Thermal Island , Isfahan , Air Pollution , Estimation of Temperature , Satellite Image
  • Masood Jalali, Allah Morad Taherian Zad, Mahdi Doostkamian * Pages 131-152
    Introduction
    A large amount of water in the seas and oceans on the earth is concentrated and a large body of water, water, gases, aerosol particles and momentum exchanges with the atmosphere (big et al 2003:275). So, how patterns of atmospheric circulation, especially with the increasingly moisture flux patterns are consistent with pressure (ghaemi 1994:272). Various forms of water transfer in addition to the dependence on atmospheric general circulation in different time periods. In general, two types of moisture flux vertical and horizontal in the atmosphere are always combined with each other and only possible and under certain conditions the amount of them may increase flux horizontally by advection of air to carry moisture from the Evaporative to other parts of flux and vertical evaporative to transfer moisture from the surface into the atmosphere takes place in the vertical direction (Lindesay and. Dabreton 1993: 13). Transfer of water vapor in the atmosphere conditions are directly related to atmospheric circulation and changes in atmospheric circulation over time, the amount and the flow of moisture as well as altered. It pays to check the moisture flux convergence fact that wind is causing how much water vapor at different levels of the atmosphere(Masoudian and Mohammadi 2010: 47-70).
    Materials and Methods
    In this study in order to investigate explores the convergence of moisture flux and atmospheric water precipitation in the spring rainfall, the researchers used two types of databases:Environmental data: environmental data is collected in two parts. Data is obtained in two parts, in the first part of 1460 seeking observations from daily rainfall synoptic and climatic stations and humidity and climate station 483 from 1340 to 1383 Esfezari database is used. The division of the distance is 15.15 km spatial resolution data is in the Lambert cone-shaped image are written. It has the cell density is 7187 cells throughout Iran. In order to increase the temporal resolution of the database daily precipitation observations from 1383 to the end of 1390 using the same method and the same spatial resolution, interpolation is added to the data base.
    Then the database is used to determine the rainy day of three conditions:1 day which has at least 3 types of coverage in distance is a 2 mm and above have experienced at least two days to continue.
    3 cover at least 50 percent of place.
    2. The weather data: in this section to determine the flux convergence humidity and water precipitation rain sweeping spring of data, sea level pressure, water temperature, wind component zonal and meridional moisture, especially in heights of the database (NCEP / NCAR) dependent on the United States of America at the National Oceanic and atmospheric levels of 850, 700 and 1000 hPa is extracted.
    Results and Discussion
    In search of moisture flux and the participation levels of water to provide humidity, precipitation in the spring of Iran or in other words in the convergence of moisture flux toward Iran fluctuations and changes observed is such that these variations in the levels of the sea, 850 700 hp with an intensity that has faced. In between the Arabian Sea, Persian Gulf, Red Sea, at 850 and 700 hPa as pronounced in flux, humidity, precipitation in the spring of and the Caspian Sea, in addition to providing moisture coastal areas in sea level of moisture sources Home rains of spring Northwest.
    In this regard, the Mediterranean when the low pressure Sudan is activated by South Stream and East Mediterranean to the northern Red Sea moves and in accordance with flowing toward the south and southwest of Iran is shifted while the humidity of the Black Sea, because of systems and the presence of northern and northeastern Iran East side to side pass. Minimal role in flux rainfall events in the spring of Iran, especially in the south-eastern region studied the Indian subcontinent, and any time that the transfer of moisture from the Indian subcontinent and the Arabian Sea synchronized as can moisture precipitation in the southeast of the country meet. Thus it can be seen that between the Red Sea and Gulf of changes lower levels in the atmosphere, there is no coordination with the Arabian Sea and Oman. At the same time, the autocorrelation Space moisture in the country has shown that moisture values prized high autocorrelation high ledges in the spring in the coastal strip of the Caspian Sea, Persian Gulf and parts of the North West there; so that the least amount of change autocorrelation Space
    Conclusions
    This study aimed to study the convergence of moisture flux and atmospheric water precipitation and identify sources of moisture in the spring precipitation has been Iran. For this purpose, the daily precipitation data of 483 synoptic, climatological and rain in a 50-year period (1961- 2010) is used. After extraction rainy days sweeping through cluster analysis patterns flux convergence humidity and water precipitation atmosphere of spring precipitation has been identified and then proceed to derive maps of sea level pressure, 850 and 700 hp with flux convergence humidity and water precipitation barley the study area is. pressure East, Turkey, Saudi pressure, moisture flux convergence of high pressure low pressure Siberian- Saudi Arabia, Sudan and moisture flux convergence of Siberian high pressure - Turkmenistan low pressure, low pressure Sudan. Most of the moisture content and moisture flux convergence of the Arabian Sea, Persian Gulf, Caspian Sea and the Red Sea and the Mediterranean and Black upper atmosphere at levels lower atmosphere.
    Keywords: convergence humidity, water temperature, rainfall in the spring, Iran
  • Hojatolah Daneshmand, Peyman Mahmoudi * Pages 153-168
    Introduction
    Variability of climatic phenomena is manifested in three intervals in the form of trend, oscillation, and fluctuation. Trend refers to the long-term behavior of time series, and fluctuation reflects the unique and unrepeatable behaviors. However, the distinctive aspect of oscillation is its recurring pattern. In this case, after a while the climatic system presents a configuration “similar” to the previous pattern with a slight difference. Many climate oscillations in a fixed time period (e.g., one year or less) are marked with monthly or seasonal periods. These cycles are called apparent cycles or periods. Many other climatic cycles are not manifested immediately, but rather occur gradually over time. This type of cycles is known as latent cycles.
    Drought as a climatic phenomenon is considered as one of the most important natural disasters due to its special vastness and short-term and long-term economic, social, and environmental consequences. Thus, studies conducted to reveal the spatiotemporal behavior of this phenomenon and particularly periodicities can be very useful for predicting this phenomenon in the future. In addition, these studies can be used to identify the causes of drought.
    Iran, a vast country with precipitation about one third of global precipitation, is located in arid and semi-arid areas of the world, and aridness is considered as its main natural and climatic characteristic. However, in recent years, precipitation anomalies are increased in different regions of Iran due to reasons often related to global climate changes, and also severe temporal and spatial fluctuations of drought have imposed huge damage to the economy of the country, especially in recent decades.
    Materials and Methods
    Iran is a geographically uneven country with the average height of the sea level of about 1250 meters. Owing to its geographical situation, climate of Iran is dependent on some elements of the general air circulation active in a special spatial and temporal range. Meanwhile, the subtropical high pressure system is the dominant phenomenon of warm period of the year in Iran which brings under its domination most parts of the country in the southern mountains of Alborz. Of course, the role of roughness height and latitude in the continuation of its dominance in warm period of the year appears important as well. In general, Iran’s temperature increases from north to south and west to east. The reason for this feature is the existence of highlands in north and west of the country as well as the gradual decrease of radiation angle towards more northern latitudes.
    This study, attempts to identify the periodic behavior of droughts in Iran; therefore, a step can be taken toward more accurate prediction of this climate risk in future based on the knowledge achieved. To achieve this goal, the monthly precipitation data for a period of 41 synoptic stations for a period of 31 years (1983-2013) received from Iran meteorological organization was used. Then, to identify different degrees of drought, effective drought index (EDI) was used. The main purpose of this index is to assign a numerical value to each precipitation incident in monthly scale to be able to compare the areas with different climates. Then, to identify the dominant periods in drought time series of stations, wavelet transform is used. In this study, the frequency is shown as period per month. In other words, the period or cycle is measured in terms of months. Low frequencies represent the large periodic cycles, and high frequencies represent the small periodic cycles.
    Results and Discussion
    The results showed that the dominant periods in time series of effective drought index (EDI) in different stations of Iran vary significantly and include the period of 24-28 months to 210-220 months. Moreover, in a number of stations, dominant periodic intervals are seen, including the two period intervals of 108-120 and 60-80 months. However, in general, this behavior is not observed at all stations; in fact, we are faced with periodic variability in most stations. Except for the semi-northern half of the central Iran, the periodic interval is increasing in other parts. In other words, the periodic interval is opening. In the early periods, short-term periodic intervals are observed. However, periodic intervals are approaching to large ranges during the period and at the end of the series. Thus, throughout the country, it can be concluded that periodic intervals re oriented towards long-term periods with very mild slope. This can indicate that large-scale factors play an important role in the creation of periodic intervals, and the role of the regional factors is declining.
    Conclusions
    The results showed that periodic intervals were shorter at the beginning but longer at the end of time series. This suggests that the probability of the incidence of drought in Iran is increasing. Another result of this study showed that the interval between occurrence of droughts were longer at the beginning and then shorter at the end of times series. That is, the occurrence of droughts in Iran has long-term periods of return at the beginning and shorter ones at the end.
    Keywords: Drought, Wavelet transform, Frequency, Periodic interval
  • Mohammad Javad Yousefi , Alireza Rashki *, Mohammad Farzam, Mohammad Taghi Kashki Pages 169-185
    Introduction
    Wind processes include deposit transportation by wind which occurs in different areas such as coastal regions, cold and hot deserts, and agricultural lands. Common feature of all these locations is that the vegetation is sparse and/or there is no vegetation. Aeolian processes lead to the dispersion of clay particles, mud, sand, and grit and create sand hills in different regions. These regions are varied in terms of air quality, soil chemistry and nutrients due to the migration of these hills through strong winds and their invasion to nearby ecosystems. Many studies have been done in recent years on sand particles and their morphology in Iran which have shifted from qualitative to quantitative view over time. The current study attempts to present a quantitative-analytical comparison on granulometry and morphoscopy of sands and plants' morphological indicators with morphometric indicators of Nebkas in Sarakhs region to better specify the nature of them and analyze their creation by finding their similarity and differences.
    Materials and Methods
    Nebkas, which is studied in this work, extends in western Nebkalands of Sarakhs from northwest to southwest in geographical coordination from 36 28' 41" to 36 37' 59" north and from 61 1' 30" to 61 3' 43" east. These regions are of critical centers of wind erosion in Sarakhs town and dominant wind direction is from west north to east south. Three sites in northern, almost central, and southern parts of Nebkalands were selected after reviewing satellite images and field surveys. First site (Yaztape) is located in the most northern point of the region where most Nebkas have alhagi plants. Second site (Tam Rasoul) is located in the furthermost southern part of site 1 and dominant plant of these Nabkas is wild rue. Third site (Samad Abad) is located in the southern part of study area and dominant plant of this Nebka is stipagrostis plumose. To study the samples of Nebkas' wind deposits, two transects in Yaztape area (northern part of Nabkaland), two transects In Tam Rasoul (central parts of the area), and two transects in Samad Abad (southern part of the area) were obtained. The length of each transect was 100 meters and the locations of transects were selected randomly. To study the indicators of plant morphology and morphometric indicators of Nebka and also to investigate the relations between them along each transects, parameters such as height, length, and volume of Nebka and height, leaf diameter, volume and the environment of the plant and also samples of wind deposits of each Nebka were used. Five samples were selected from deposit samples of each three study area along wind blast through Nebka random selection to perform pH tests, EC, texture, mineralogy, and grading operations. Mineralogy of deposits from each three sites was determined using XRD test. Hydrometric method was used to determine deposit texture. Wet sieve was used to determine deposit grading indicators and more common formulas were applied to specify mean, skewness, stretch, and standard deviation and Folk's classification. Correlation coefficient was calculated to investigate the effect of plant morphology indicators on morphometric indicators of Nebka more accurately.
    Results and Discussion
    Mineralogy tests (XRD)
    Based on results of mineralogy tests, it can be observed that minerals of all three sites are almost similar and generally have deposit origin.
    Deposit texture test
    Removal area of deposits is not far from sedimentation area as the portion of sand is very high in deposits and also all deposit samples are placed in sand texture class.
    pH determination and EC tests
    Electrical conductivity of deposits is very low and this low electrical conductivity is decreased from site 1 (Yzatape) towards site 3 (Samad Abad) while the distance of deposit transportation is increased. Analysis of deposits' pH based on deposit transportation distance shows that pH of wind deposits increases with deposit transportation distance.
    Correlation of plant morphology indicators with Nebka morphometric indicators
    Highest correlation coefficient is between plant volume indicators and Nebka's volume. Generally, large diameter of Nebka creates the highest correlation with Nebka's morphometric indicators and environment and plant volume indicators come after that. This study shows that the indicator of plant height among plant morphology has the lowest effect on Nebka's morphometric indicators. Analysis of explanation coefficient of studied indicators shows that the strongest explanatory relation among studied indicators is between plant volume and Nebka volume.
    Studying plant morphology and Nebka morphometric parameters
    Studies done show that the most important factor affecting Nebka morphometric indicators is not deposit transportation distance but the most important indicator of plant morphology is studied and the effective factor of this research is plant volume.
    Grading tests
    Plant volume indicator is more effective in changes of Nebka's deposit diameter than the indicator of deposit transportation distance. Also, it can be said that deposit transportation distance is between 20 and 50 Km as D50 of all samples and the average diameter of most deposit grins is in the class of very fine sand.
    Conclusions
    Considering the results of mineralogy tests, deposit texture determination, evidences of locals, and dominant wind direction, it can be argued that these regions have similar origin. It can be said that the origin of Nebkas' deposits is probably the southern regions of Turkmenistan near Iran's border as the origin of most minerals, their salts, and the grading of studied sample is sedimentary. Statistical analysis shows that indicators of plant's large diameter, plant environment and volume, and finally plant height among studied plant morphology indicators have the highest correlation coefficient with morphometric indicator of Nebkas. In other words, in a certain vegetative form which the height variations of plant is low, the indicator of plant height has less effect on morphometric indicators of Nebkas than other plant morphologic indicators. The most effective factor on Nebka's volume among studied plant morphology indicators is plant volume. Analysis of Nebka's height trend shows that this morphometric indicator of Nebka decreases gradually in the direction of wind so that the ability of wind regime to carry deposit reduces by increasing the distance. After investigating results of grading tests for indicators of D10, D50, and D90, and average diameter of particles, it can be said that plant volume have larger effect on the value of these indicators compared with distance from removal area. Results of deposit grading tests in these three sites showed that particles' homogeneity is very well. When skewness is considered, it can be said the further the distance of deposit carrying is, the more the value of skewness is increased and skewness is directed towards fine-grained particles. However, the effect of deposit carrying distance is less than plant volume created Nebkas. Another study done on the extension of deposit showed that as it was expected, the extension of deposits is reduced by increasing deposit carrying distance and in this case, the effect of deposit carrying distance is more than the volume of plants created Nebkas.
    Keywords: Sarakhs, Mineralogy, Grading, Nebka, Morphometry