فهرست مطالب

جغرافیا و مخاطرات محیطی - پیاپی 24 (زمستان 1396)

نشریه جغرافیا و مخاطرات محیطی
پیاپی 24 (زمستان 1396)

  • تاریخ انتشار: 1396/12/18
  • تعداد عناوین: 9
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  • مقالات
  • مرضیه سادات میراحسنی، عبدالرسول سلمان ماهینی، علیرضا سفیانیان، رضا مدرس، رضا جعفری، جهانگیر محمدی صفحات 1-22
    خطر خشکسالی تهدید کننده و مخل سیستم های کشاورزی، محیط زیستی، اجتماعی و اقتصادی حوضه آبخیز زاینده رود است. پایش خشکسالی با استفاده از تصاویر ماهواره ای می تواند نمایانگر شدت و گستره خشکسالی در مناطق با کمبود داده بارش هواشناسی بوده و کاستی مکانی و زمانی آن را جبران نماید. کارایی شاخص های پوشش گیاهی ماهواره ای مانند شاخص تفاوت پوشش گیاهی نرمال (NDVI) در تعیین میزان و شدت خشکسالی روشن است؛ اما ازآنجاکه واکنش پوشش گیاهی به خشکسالی نسبت به زمان واقعی تاخیر دارد، پایش پاسخ پوشش گیاهی به خشکسالی هواشناسی بر اساس داده های سری زمانی ماهواره ای به برنامه ریزی کاهش خطرات خشکسالی کمک شایانی می کند. در این پژوهش به بررسی مکانی-زمانی خشکسالی منطقه ای حوضه آبخیز زاینده رود طی سال های 2003 تا 2014 پرداخته شد. در این راستا، با بهره گیری از 84 تصویر سری زمانی شاخص NDVI محصولات ماهواره مودیس از فصل رشد منطقه، شاخص وضعیت پوشش گیاهی (VCI) که یک شاخص نرمال شده جهت ارزیابی خشکسالی است، محاسبه گردید. سپس پوشش هر طبقه از شدت خشکسالی حاصل از این تصاویر برای دوره زمانی پایش شده تعیین گردید. شاخص بارش استاندارد (SPI) مربوط به 26 ایستگاه جهت ارزیابی شاخص ماهواره ای محاسبه شده و ضریب همبستگی این شاخص با میانگین شاخص VCI حاصل ارزیابی گردید. میزان تاخیر خشکسالی هواشناسی به پوشش گیاهی با بررسی همبستگی شاخص میانگین NDVI با میانگینSPI و نمودارهای تغییرات داده های VCI با داده های SPI وNDVI ارزیابی شد. نتایج پایش مکانی-زمانی نشان داد که قسمت های مرکز رو به شمال حوضه آبخیز زاینده رود، شرق و جنوب شرقی آن (محل قرارگیری تالاب گاوخونی) در طول دوره مطالعه به طور مداوم با خشکسالی شدید روبه رو بوده و در سال های 2008 و 2014 این خشکسالی بسیار شدید شده است. همچنین نتایج حاکی از تاخیر زمانی 6 ماهه شاخص خشکسالی هواشناسی با شاخص خشکسالی ماهواره ای VCI و معنی داری 9/0 شاخص SPI با شاخص VCI است که نشان می دهد می توان از شاخص های ماهواره ای در نبود شاخص های هواشناسی برای بررسی خشکسالی حوضه آبخیز مورد مطالعه استفاده نمود.
    کلیدواژگان: پوشش گیاهی، تاخیر پاسخ، MODIS-NDVI، همبستگی پیرسون
  • امیر پیروز کلاهی آذز، غلام رضا مقامی مقیم صفحات 23-40
    زمین لرزه گشت در 27 فروردین 1392 مناطقی از جنوب شرق ایران، جنوب افغانستان و غرب پاکستان را لرزاند. با توجه به انطباق کانون سطحی این زمین لرزه با منطقه ای کم جمعیت، میزان خسارات جانی و مالی آن بسیار اندک بود. بااین وجود به دلیل قدرت زیاد (7/7 ریشتر) و عمق کانونی ژرف این زمین لرزه در برخی از سرزمین های دور مانند هند و کشورهای حاشیه جنوبی خلیج فارس حس شده است. نکته قابل توجه، وقوع این زمین لرزه در زیرسامانه گسلی سراوان و امکان تاثیرپذیری آن از رخداد مذکور است. در این تحقیق، میزان این تاثیرپذیری موردبررسی قرارگرفته است. ازاین رو تغییرات تنش هم لرزه ای ناشی از زمین لرزه مذکور به روش مدل انتقال تنش کولمب محاسبه شد. نتایج به دست آمده موید تاثیرپذیری سامانه گسلی سراوان از زمین لرزه موردنظر بوده است. درعین حال پراکنش فعالیت های پس لرزه ای در نواحی افزایش تنش هم لرزه ای، بیانگر اعتبار روش مورداستفاده برای ارزیابی و شناسایی مناطق پرخطر لرزه ای است. با توجه به شرایط خاص مناطق آسیب دیده از زمین لرزه اصلی (به ویژه ساختمان های سست شده در اثر آن)، فعالیت های پس لرزه ای به مراتب می توانند مخرب تر از زمین لرزه اصلی باشند. لذا تشخیص مناطق پرخطر فعالیت های پس لرزه ای می تواند نقش بسزایی در کاهش و کنترل صدمات ناشی از آن ها داشته باشد.
    کلیدواژگان: تغییر تنش کولمب، تنش هم لرزه ای، توزیع پس لرزه ها، مکران، مخاطرات طبیعی
  • محمد مهدی حسین زاده، سمیه خالقی، فراز واحدی فر صفحات 41-62
    تغییرات مجرای رودخانه، فرسایش کناره ای و رسوب گذاری کناره ای، فرآیندهای طبیعی رودخانه های آبرفتی هستند که باعث تخریب زمین های کشاورزی اطراف و خسارت به تاسیسات انسانی اطراف رودخانه می شود؛ بنابراین فرسایش کناره و تغییرات کانال رود به عنوان یک مسئله اجتماعی، محیطی و اقتصادی است که اغلب خسارات جبران ناپذیری را به ساکنان و تاسیسات حاشیه رودخانه وارد می سازد. در این پژوهش از دو روش NBS و BEHI جهت ارزیابی وضعیت رودخانه قرانقو چای از نظر الگو و اندازه گیری میزان فرسایش کناره ای و ناپایداری کناره ها استفاده شده است. درروش NBS از نسبت شعاع انحناء به عرض دبی لبالبی و نسبت حداکثر عمق نزدیک کرانه به متوسط عمق دبی لبالبی استفاده شده است. طبق این روش در نسبت شعاع انحناء به عرض دبی لبالبی، مقاطع دارای فرسایش شدید تا متوسط می باشند و فقط در مقطع 7 فرسایش در حد کم است و در روش نسبت حداکثر عمق نزدیک کرانه به متوسط عمق دبی لبالبی، در مقطع اول خیلی کم و در مقطع دوم شدید است و در بقیه مقاطع میزان فرسایش دارای مقادیر کم تا متوسط می باشد.در روش BEHI نتایج به دست آمده نشان می دهد که فرسایش کناره ای در هر دو کناره راست و چپ مقاطع عرضی وجود دارد؛ به طوری که در کناره سمت راست رودخانه، میزان خطر فرسایش در تمامی مقاطع از متوسط تا خیلی زیاد می باشد و فقط در مقطع 4 میزان خطر فرسایش خیلی کم بوده و همچنین در کناره های چپ رودخانه در مقاطع مذکور میزان خطر فرسایش کناره از خیلی کم تا شدید برآورد شده است. بر اساس نتایج دو مدل به طورکلی میزان و خطر فرسایش برای کناره خارجی قوس ها در محدوده الگوی پیچانرودی رودخانه قرانقو بیش تر از کناره مقابل است؛ هم چنین میزان فرسایش کناره ای در هر دو کرانه در بخش میانی بازه مورد مطالعه کاهش و در بخش انتهایی افزایش پیدا می کند و فرسایش کناره ای در بازه مورد مطالعه از عوامل مهم تولید رسوب رودخانه قرانقو محسوب می شود و خطر فرسایش کناره ای و استعداد فرسایش کناره ای در طول بازه با شدت و ضعف متفاوت در دو کناره رودخانه وجود دارد.
    کلیدواژگان: فرسایش کناره ای، تغییرات مجرا، NBS، BEHI، رودخانه قرانقو چای
  • رسول حیدری سورشجانی، یونس غلامی، زهرا سلیمی صفحات 63-80
    جوامع در سراسر جهان به طور فزاینده ای از بلایای ناشی از مخاطرات طبیعی، منازعات و فوریت های انسانی یا رویدادهای ساخته دست بشر متاثر می شوند. این بلایا اغلب در اشکال، شدت و محل های غیرمنتظره رخ می دهد که در عمل پیشگیری یا اقدام در مورد تمامی این تهدیدها را غیرممکن می سازد. افزایش تاب آوری شهرها در برابر بلایای طبیعی به ویژه زمین لرزه ها به میزان زیادی در کاهش این خسارات و همچنین زمان بهبودی جوامع موثر است. تاب آوری کالبدی، یکی از ابعاد تاثیرگذار در میزان تاب آوری جوامع است که از طریق آن می توان وضعیت جوامع را از نظر ویژگی های فیزیکی و جغرافیایی تاثیرگذار در هنگام بروز سانحه ارزیابی کرد. این پژوهش کاربردی است و با استفاده از روش توصیفی تحلیلی، با هدف شناسایی شاخص ها و عوامل موثر بر تاب آوری کالبدی، به سنجش و مقایسه زیرمعیارهای کالبدی تاب آوری در محله های فرسوده شهر بوشهر می پردازد. جامعه آماری پژوهش را ساکنین محلات قدیمی و فرسوده دهدشتی، کوتی ، بهبهانی ، شنبدی، عالی آباد، سنگی، بن مانع، مخ بلند، دواس، خواجه ها، جلالی، جبری، صلح آباد، جفره تشکیل می دهد. برای تعیین حجم نمونه از فرمول کوکران استفاده شده است، تعداد 381 پرسش نامه با استفاده از طیف لیکرت بین ساکنین این محلات توزیع شده است پایایی ابزار تحقیق با استفاده از آلفای کرونباخ 810/ برآورد شد که گویای هماهنگی و پایداری درونی بالای ابزار تحقیق است و به منظور پردازش اطلاعات جهت تجزیه وتحلیل تاب آوری بافت های فرسوده در محدوده مورد مطالعه از روش مدل یابی معادلات ساختاری، از جمله نرم افزارهای SPSS و AMOS و برای به دست آوردن نقشه موقعیت جغرافیایی محدوده مورد نظر از نرم افزار GIS استفاده شده است. درنهایت تاثیرات شاخص های کالبدی (مدیریت بحران، دسترسی، مقاومت زیرساخت ها و کیفیت ابنیه) بر میزان زلزله با استفاده از الگوی معادلات ساختاری (SEM) مورد بررسی و تحلیل قرار گرفت، که نتایج حاصله نشان می دهد که شاخص مقاومت زیرساخت ها با ضریب 75. بیشترین اثر را در تاب آوری کالبدی در محلات بافت فرسوده بوشهر دارا می باشد.
    کلیدواژگان: تاب آوری کالبدی، آسیب پذیری، محلات فرسوده، مدل یابی معادلات ساختاری، شهر بوشهر
  • محمد دارایی، بهروز ساری صراف، علی محمد خورشیددوست، پیمان محمودی صفحات 81-96
    هدف از پژوهش کنونی بررسی دورنمایی از اثرات احتمالی تغییر اقلیم بر جابه جایی زمانی تاریخ وقوع اولین و آخرین یخبندان های پاییزه و بهاره ایران است. بدین منظور از داده های دیده بانی 43 ایستگاه همدید کشور (1981-2010) و داده های شبیه سازی شده LARS WG در دو مدل آب وهوای جهانی GFCM21 و HadCM3 در بازه های زمانی (2065-2046) و (2099-2080)، تحت سه سناریوی انتشار A1B، A2 و B1استفاده گردید. نتایج، بیانگر جابه جایی اولین یخبندان پاییزه به سمت اوایل زمستان و جابه جایی آخرین یخبندان بهاره به سوی اواخر زمستان در گستره ایران است. پراکنش زمانی-مکانی تغییرات متفاوت است؛ به گونه ای که بیشترین جابه جایی های مثبت در رخداد اولین یخبندان پاییزه در دوره (2065-2046) در ایستگاه هایی چون خرم آباد، رشت و گرگان مشاهده می شود. میزان تغییرات در ایستگاه های شمال شرقی (سبزوار و سمنان)، نیمه جنوبی (کرمان، بم و آباده) و بیشتر ایستگاه های شمال غرب نسبت به دیگر مناطق کمتر است. در دوره (2080-2099) بیشترین روند منفی در ایستگاه های گرگان، رشت، اردبیل و شهرکرد خواهد بود. خوی، قزوین، بم و کاشان کمترین جابه جایی منفی خواهند داشت.
    کلیدواژگان: تغییر اقلیم، اولین یخبندان پاییزه، آخرین یخبندان بهاره، مدل LARS WG، ایران
  • سمیرا جعفری آذر، غلامرضا سبزقبایی، مرتضی توکلی، سولماز دشتی صفحات 97-119
    وجود تالاب ها و پهنه های آبی منحصربه فردی نظیر تالاب بین المللی شادگان، خورالامیه و خورموسی با ویژگی های خاص علاوه بر اینکه یک ثروت ملی به شمار می آیند، از جایگاه و اهمیت محلی، ملی و بین-المللی برخوردار می باشند؛ اما متاسفانه این اکوسیستم ها امروزه با تنگناهای بسیاری از جمله ریسک های ناشی از عوامل طبیعی و فعالیت های انسانی همراه هستند؛ بنابراین با توجه به اهمیت حفاظت از محیط-زیست بالاخص اکوسیستم های آبی و تالاب ها، این تحقیق در سال 1394 با هدف شناسایی عوامل تخریب و تهدید تالاب بین المللی شادگان، خورالامیه و خورموسی به منظور وضع قوانین کارآمد و اتخاذ مکانیسم های مناسب در برخورد با تخریب کنندگان و مدیریت صحیح و پایدار، صورت پذیرفت. بدین منظور ابتدا با استفاده از تکنیک دلفی ریسک های شاخص تالاب شناسایی و به منظور رتبه بندی و مشخص نمودن اولویت عوامل تهدید، از روش های تصمیم گیری چند معیاره AHP و TOPSIS استفاده گردید. نتایج اولویت بندی 35 عامل ریسک در دو گروه طبیعی و زیست محیطی (ریسک های فیزیکوشیمیایی، بیولوژیکی، اقتصادی-اجتماعی و فرهنگی) بر اساس سه شاخص شدت اثر، احتمال وقوع و حساسیت محیط پذیرنده حاکی از آن است که به ترتیب برحسب میزان نزدیکی (CL+)، پدیده خشکسالی و تغییرات اقلیم (1)، برداشت آب در بالادست و طرح توسعه آبی (9106/0)، احداث سد در بالا دست (91/0) و آلودگی نفتی (7991/0) به ترتیب در اولویت های اول تا چهارم می باشند. همچنین نتایج نشان می دهد که پدیده خشکسالی و تغییرات اقلیم، برداشت آب در بالادست (طرح توسعه آبی)، احداث سد در رده بحرانی و آلودگی نفتی، پساب های صنعتی و تردد لنج ، شناور و قایق ها در رده غیرقابل تحمل برای تالاب قرار دارند؛ بنابراین بدون تردید شناخت درست و دقیق عوامل تهدید کننده تالاب ها بر اساس اهمیت و میزان تاثیرگذاری آن ها می تواند زمینه را برای جلوگیری و مقابله اصولی تر با این عوامل و نیز تهیه و اجرای دقیق طرح های حفاظت از تالاب ها و مدیریت زیست محیطی آن ها فراهم آورد.
    کلیدواژگان: ارزیابی مخاطرات، زیست محیطی، تالاب بین المللی، تصمیم گیری چندمعیاره
  • محسن جان پرور، ریحانه صالح آبادی، سیده سمیره حسینی صفحات 121-141
    برای کشورها فضای مرزی به طور فزاینده ای به حفاظت و دفاع نیاز دارد. همچنین فضای مرزی به صورت فزاینده ای مرکز ایدئولوژی و عملکرد کشورها، مکانی برای سیاست های سرمایه گذاری مهم و منابع معدنی است و دورترین منطقه حاکمیتی است. در جهان امروز که مرزها در انواع مختلف و با ویژگی های بسیار متنوعی وجود دارند، رویکردها نسبت به مدیریت مرز نیز به صورت مشابه بسیار متنوع است. یکی از این رویکردها ایجاد دیوار مرزی است که توسط بسیاری از کشورها ازجمله جمهوری اسلامی ایران در حال پیگیری است. باید توجه نمود که دیوار مرزی یکی از راهبردهای کنترل مرز به صورت سلبی است که ورود و خروج افراد، کالا و... را تحت کنترل شدید قرار می دهد. باید بیان نمود که این دیوار مرزی که به نوعی دیوار امنیتی برای کشور محسوب می گردد خود زمینه ساز بروز مخاطرات محیطی است. مخاطرات محیطی خود به دو دسته بلای طبیعی (سیل، طوفان، زمین لرزه و...) و بلایای انسانی (نابودی زیست محیطی، گرم شدن کره زمین و...) تقسیم می شوند. مقاله حاضر با روش توصیفی- تحلیلی درصدد بررسی این نوع مخاطرات ناشی از احداث دیوار مرزی در منطقه سیستان و بلوچستان است و سپس با استفاده از روش توان رتبه ای به طبقه بندی این مخاطرات می پردازد تا مهم ترین مخاطره ای که منطقه را تهدید می کند به دست آید. نتایج تحقیق نشان می دهد مخاطرات ناشی از احداث دیوار مرزی در منطقه در 9 مورد مخاطرات طبیعی (نابودی گیاهان، انقراض جانوران، بین رفتن صنعت اکوتوریسم؛ افزایش فرسایش بادی منطقه) و مخاطرات انسانی (تفکیک فرهنگی- قومی دو سوی مرز؛ هدایت افراد به فضاهای ناشناخته؛ افزایش گرایش به قاچاق مواد مخدر و اسلحه؛ کاهش اعتماد به حکومت مرکزی؛ هزینه های بالای اقتصادی) تقسیم می گردند. در آخر با استفاده از روش توان رتبه ای مهم ترین مخاطره ای که منطقه را تهدید می کند کاهش اعتماد به دولت مرکزی با وزن 81 به دست آمد که خود می تواند زمینه ساز بسیاری از مشکلات آتی برای در سطح منطقه ای و ملی باشد.
    کلیدواژگان: مخاطرات محیطی، مرز، دیوار مرزی، استان سیستان و بلوچستان
  • علیرضا اولیایی، ناصر پرویان، عذرا خسروی صفحات 143-158
    بحران آب در بسیاری از کشورهای جهان و ازجمله کشورهای واقع در کمربند خشک کره زمین مانند ایران، روز به روز ابعاد پیچیده تری به خود گرفته است. با شدت گرفتن مشکل بحران آب بسیاری از پژوهشگران حوزه منابع آب در پی ارائه راهکارهایی جهت مقابله با این بحران هستند. منابع آب در سازندهای سخت، از مهم ترین منابع آب شیرین به حساب می آیند و با توجه به گسترش زیاد این سازندها در کشور، به طرق مختلف سعی بر شناخت آن ها شده است. این پژوهش سعی دارد با بررسی پراکنش چشمه های موجود در منطقه به عنوان یکی از نشانگرهای منابع آبی به بررسی منابع آب زیرزمینی در سازندهای سخت بپردازد. بدین منظور جهت تولید نقشه پیش بینی منابع آب زیرزمینی در حوزه آبخیز کلات نادری، از مدل سازی با نرم افزار مکسنت بر پایه رگرسیون لجستیک، تکنیک های سیستم اطلاعات جغرافیایی (ARCGIS) و سنجش ازدور (RS) استفاده گردید. نتایج نمودارهای آنالیز حساسیت، نوع رابطه عوامل محیطی و مرفومتریک را با رخنمون چشمه ها نشان دادند. همچنین نتایج حاصل از روش متعامد اعتبارسازی منحنی جک نایف، نشان داد که مهم ترین عامل در مدل سازی پیش بینی منابع آب زیرزمینی، پارامتر بارندگی و سنگ شناسی بوده است. درنهایت نقشه پیش بینی منابع آب زیرزمینی به چهار طبقه کیفی پتانسیل خیلی کم، کم، متوسط و زیاد تقسیم گردید که به ترتیب 03/33، 07/14، 01/4 و 9/48 درصد از حوضه آبخیز کلات را در بر می گیرد. نتایج درنهایت دقت مدل با استفاده از منحنی ROC، 3/92 درصد تخمین زده شد که نشان دهنده دقت بالای مدل در تحلیل فراوانی چشمه ها در منطقه مورد مطالعه است. با توجه به مطالعات اخیر و تطابق خوب این مدل با داده های موجود، می تواند روشی مطلوب در شناسایی منابع آب زیرزمینی به ویژه در سازند های سخت باشد و استفاده از آن در جهت برنامه ریزی های محیطی بسیار مفید و کارا باشد.
    کلیدواژگان: کلات نادری، Maxent، رگرسیون لجستیک، منابع آب، سازندهای سخت
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  • Marziehsadat Mirahsani, Abdulrassul Salman Mahini, Alireza Soffianian, Reza Moddares, Reza Jafari, Jahangir Mohammadi Pages 1-22
    Introduction Zayandeh-Rud Basin (ZRB) is one of the most strategic river basins of Iran where the majority of the basin has a typical arid and semi-arid climate with frequent droughts. Drought is a recurrent phenomenon that affects humid as well as arid regions to some degree which has large adverse consequences on the socio-economic condition of people living in drought-prone areas through its impact on water availability and quality and ecosystem health. Standardized precipitation index (SPI) is a station-based drought index which measures precipitation. The limitation of SPI is continuous spatial inability and coverage. On a regional scale, SPI cannot monitor and illustrate the detailed pattern of drought conditions spatially, particularly in regions with a high degree of spatial variability or inadequate meteorological stations. As the spatiotemporal identification of drought events is very complex, drought indices are mainly beneficial in order to monitor the impact of climate variability on vegetation (Khosravi & Akhund-Zadeh, 2015). Remotely sensed spectral indices can determine the quantification of vegetation drought. Moderate Resolution Imaging Spectro-radiometer (MODIS) has been used by various researchers from diverse disciplines globally. Monitoring vegetation using satellite imagery is also comprehensively applied to monitor and assess drought condition and etc. The Normalized Difference Vegetation Index (NDVI) (Tucker, 1979) is the oldest remotely sensed vegetation index in use and remains as the most widely used by the remote sensing community. The efficiency of NDVI in evaluation of vegetation response to drought has been tried out (Tucker & Choudhury, 1987) which provides a common measure of the health and condition of vegetation. Nevertheless, NDVI has some deficiencies; NDVI is not sensitive to soil color, atmospheric effects, and illumination and observation geometry. The limitation of NDVI in drought monitoring is that NDVI cannot indicate the drought severity alone because of obvious time lag of NDVI response to precipitation and little effect of weighty rainfall events later in the growing season (plant seed production period) on NDVI (Ganesh, 2007). Therefore, NDVI-Vegetation Condition Index (Kogan, 1995) normalizes NDVI for each pixel over time based on its minimum and maximum values. The VCI was applied successfully for drought monitoring by various researchers. Onset of drought and the duration, intensity and impact of drought can be measured and detected by the VCI. In addition, identifying the spatio-temporal variability of vegetation conditions associated with perturbation as a result of precipitation shortage is allowed by VCI. VCI has been compared with field reflectance measurements, biomass and vegetation density. It is proven that VCI could be a suitable sign of the impact of climate on health and conditions of vegetation. The clear benefit of VCI is simplifying of the computation because it does not need station observation data. As VCI is a satellite-based drought product, it can process globally near real-time data at a reasonably high spatial resolution. VCI is appropriate to make a relative assessment of variations in the NDVI signal by filtering out the contribution of local geographic resources to the spatial variability of NDVI. In addition, VCI evaluates variations in the NDVI signal during time through decreasing the effect of local ecosystem variables. This research aims to assess spatial distribution of VCI index through spatiotemporal monitoring of it using MODIS NDVI time series products in growth season over ZRB from April to October 2003 to 2014 (Mrahsani, Salman Mahini, Soffianian, Modarres, Jafari & Mohamadi, 2015).
    Material and
    Methods
    2.1. Study area
    ZRB or Gavkhuni Basin is known as a very important river basin of Iran. ZRB with area of 41485.65 km2 (5.2% of the country's total area) is located between the 50° 24′ to 53° 24′ longitudes and 31° 11′ to 33° 42′ latitudes. Temperatures have been recorded to be hot in July, with an average of 30 ̊C, and with an average minimum temperature of 3 ̊C in January. Rainfall, which is generally very limited, is around 130 mm per year (Salemi, & Rust, 2004). In ZRB, the annual precipitation recorded ranges from 1500 mm (in snow which is only likely to be melted when temperature rises around April) in the western part to 50 mm in the eastern part (Sarhadi & Solatni, 2013).
    2.2 Data Collection
    2.2.1. Monthly MODIS/Terra NDVI
    The Monthly MODIS NDVI time series product (MOD13A3, 1 km ×1 km) images of the study area were applied from 2003 to 2014.
    2.2.2. Meteorological Drought Index
    The SPI is a station-based index which calculates the probability of precipitation in different time scales. The SPI calculation for any location is based on the long-term precipitation record for a desired period. In this research, SPI values are calculated based on precipitation data collected from 26 meteorological stations around ZRB which had the same available beginning from January 2003 to December 2014.
    2.3. Vegetation Condition Index (VCI)
    VCI is calculated and normalized using long term NDVI ranging from 0 to 100. Low values indicate vegetation stress and median values indicate average condition while high value indicates the optimized and normal condition.
    Results And Discussion
    3.1. Metrological Drought Index (Monthly SPI)
    The long-term SPI (12 months) were calculated based on precipitation data collected from 26 meteorological stations around ZRB which had the same available beginning from January 2003 to December 2014. The severity-duration and relative frequency of drought were then determined per time scale and station.
    3.2. Vegetation Condition Index (VCI)
    In the present study, the annual VCI time series maps were prepared in order to quantify drought from a long-term observation. It was found that sign and onset of drought can be clearly observed from the VCI maps from July to October 2003 and July to October 2005. The slope of fluctuation of the precipitation is slow during 2004 to 2006. From October to June 2007 the condition was improved all over the basin. Nevertheless, a severe drought condition prevailed all over growth season of the year 2008 all over ZRB. The slope of precipitation is slow during 2008 to 2009. The onset and extent of drought can be clearly observed from the VCI maps of April 2008 to end of growth season. Acute water stress is evident over the basin during June 2008 to April 2009. From April to May 2010, the condition was improved all over the basin. For a second time, a severe drought condition prevailed all over growth season of the year 2011 all over of ZRB. From April to May 2011, the condition was improved all over the basin, while in September the basin have faced drought again, this cycle is repeated in the end of growth season of the year 2014. Uneven distribution of rainfall causing spatial variation in vegetation health has a great influence on variation of agricultural yield of ZRB. Since the precipitations in the eastern, northern and central districts of the basin are much less than the western districts, the vegetation condition was visibly stressed in the Gav-Khuni wetland and agricultural lands in east of the basin. The vegetation health was only found normal in ZRB during the year 2007 and 2010. In 2008, the basin had been covered mostly by very high drought categories, followed by 2010 and 2014. High drought categories were mostly formed in 2011, followed by 2012 and 2013.In addition, in 2012, ZRB was mainly covered by relatively high drought, followed by 2014. The biggest area covered by moderately drought category belongs to 2012. The biggest area covered by normal category belongs to 2007, followed by 2006.
    Conclusion One of strengths of the MODIS sensor is the conciliation and reconciliation between reasonable spatial resolution and regular image acquisition. It is necessary to use remote sensing data beside other datasets from other sources because of the growing demand for data and escalation analysis. This causes an essential role for remote sensing techniques in the climatological and meteorological applications. The drought was assessed through monitoring vegetation condition using VCI; subsequently, its correlation with SPI was obtained to be 0.83, respectively. Then, the area of each category covered by VCI was calculated. Results indicate that VCI can present consistent results with strong correlation to SPI. In addition, results show usefulness of VCI in drought monitoring studies despite the wide range of climatic conditions in the region. In addition, the area of normal category covered by VCI in the basin is coincident during the time period except 2008 and 2011 during which severe meteorological drought had been occurred. However, it seems that vegetation condition is affected by facilitating irrigation of cultivated lands. In addition to extraction of groundwater and wells, the irrigation is influenced by opening the floodgate of Zayandeh-Rud Dam in the basin. Hence, it is essential to consider hydrologic drought in seasonal time scale to have a better image of water scarcity for different water demands such as agriculture and have a better water management and planning in future studies (Modarres & Silva, 2007).
    Keywords: Vegetation, Lag response, MODIS-NDVI, Pearson Correlation
  • Amir Piroz Kolahi Azar, Gholam Reza Maghami, Moghim Pages 23-40
    1. Introduction
    Earthquake is one of the most perilous natural hazards which threatens the lives and imposes massive financial loss on societies. Due to its location in the Alpine-Himalayan belt, Iran is affected by this phenomenon. Damages caused by earthquakes are not limited to the main quake, and sometimes aftershocks also cause extensive destructions. One of the ways that can predict possible aftershock activities through the faults influenced around the main quake is the Coulomb stress transfer method. This method was first used by Stein in 1992 to investigate Landers earthquake aftershock activity in California. Bufe also employed this method in 2006 to study Denali fault earthquake in Alaska. In Iran, due to the weight of this issue, important studies have been done up to now. Jafari-Hajati and Agh-Atabai have used this method in 2012 for Silakhor and Qeshm earthquakes. In 2014, Sarkarinejad and Ansari utilized the method for Rudbar earthquake. Although studies have been conducted so far, many of Iran’s major earthquakes have not been considered in this regard, despite their importance. Among them, Gosht earthquake could be mentioned that occurred on April 16, 2013 with magnitude of 7.7 in southeast of Iran. In the present paper, using the Coulomb stress transfer method, the relationship between Gosht earthquake and the spatial distribution of the corresponding aftershock activity is investigated. It has also been attempted to study the impact of the earthquake on Saravan fault system and tried to predict the location of the aftershock events based on the obtained results.
    2. Study Area
    The study area is located in Sistan and Balouchestan province, between the coordinates 27°47ʹN and 28°20ʹN latitude and 61°57ʹE to 62°39ʹE longitude. The area is bounded on the north, west, and east by Khash, Iran-Shahr, and Saravan counties, respectively. Access to this area is the Khash – Saravan road, which crosses the Gosht city.
    3. Material and Methods Following a library study, earthquake data gathered from the catalog of the International Institute of Seismology and Earthquake Engineering (IIEES). Earthquakes in the database were extracted from April 1973 to April 2015. Since earthquakes have been reported in different scales, the homogenization of extracted data is required. After homogenization, the magnitudes of completeness (MC) were calculated using Gutenberg-Richter power-low relation and ZMAP software package. All events smaller than MC, were excluded from the list in order to create a complete catalog and eventually 19 earthquakes remained in the desired spatio-temporal range. Okada’s analytical method and Coulomb 3.3 software package have been used to investigate the coseismic stress which was transferred by the Gosht temblor. Okada, in his method, considers the earth to be a homogeneous and elastic half-space. In this model, the faults are like rectangular discontinuities within the half-space. In this research, the focal mechanism proposed by Harvard University is used to determine the geometry of the reference fault and the corresponding rake angle. Given that Saravan fault is a reverse fault with a strike-slip component, the coefficient of friction is considered 0.6 in the calculations. Due to the tectonic setting of the area and the relatively high depth of the earthquake, it is not possible to measure the length of the failure of the reference fault, and therefore, the experimental relations provided by Wells and Coppersmith (1994) have been used.
    3. Results and Discussion
    The study area is one of the most active parts of the Alpine-Himalayan orogenic belt. The active subduction of Makran as a part of northward convergence of the Arabian plate toward the Iranian micro-continent causes compressive tensions along North-South direction in this tectonic zone. Owing to such pressure, the crust have been cracked and thickened by reverse faulting and folding. A relatively large gap between trench and volcanic arc (more than 500 kms) and the wide width of the Makran accretionary prism can be attributed to the relatively low angle of the subduction slab. Since the subduction of the late Cretaceous is still ongoing, this tectonic zone can be considered seismically as one of the most active regions of Iran. Most of the seismic activity of this range can be attributed to trust faulting, which occur mainly at low to mid-depths. The lithosphere thickness in this area is estimated to be about 35 kms. Therefore, the occurrences of earthquakes up to depth of 35 kms are in correspondence with the lithospheric fault systems, while deeper events are linked with the subducting slab and Wadati-Benioff zone. Some researchers have considered Saravan fault as a right-lateral strike-slip fault. Near vertical transvers faults with a right-lateral shear sense have caused some displacements along the Saravan fault and alluvial deposits. In this regard, the activity of transverse faults can be considered more recent than Saravan fault. The most important of these transverse faults is the Gosht fault. Based on Coulomb stress transfer criterion, stress released during an earthquake can provoke the adjacent faults. The Coulomb criterion says earthquakes occur when the shear stress of the earth’s crust exceeds from the shear strength of rocks along the fault. At this time, the rock is surrendered and the stored tension energy is released at a relatively short time. Due to the lithospheric thickness of the study region, earthquakes occurred up to depth of 35 kms can be related with Saravan fault activities. Static stress transfer of Gosht earthquake can be investigated in two states: i) at depths less than 35 kms, and ii) 35-120 km. Due to the ambiguity in the focal mechanism solution and the impossibility of utilizing surface evidences to detect the earthquake fault owing to the relatively high focal depth, both nodal plains can be considered as the causing fault of Gosht earthquake. Therefore, the Coulomb stress transfer for each of the nodes is calculated separately. As it is expected, the aftershock activities occurred locally in accordance with the regions of increasing static tension. The aftershock sequence of Gosht earthquake consists of six events with magnitudes of more than 4.3, three of them have focal depths of more than 35 km and others have depths less than 35 km. Events with a focal depth of more than 35 km are related to the activity of the sub-ducting slab and events with less focal depth are associated with the activity of the Saravan fault system.
    4. Conclusions
    The study of Gosht earthquake impact on Saravan fault confirms the significant transfer of Coulomb stress. In the case of strike-slip receiver fault the static stress change is much less with respect to a receiver fault with the transpressional geometry. It is important to note the location of three shallow afterschocks is consonant with the increasing stress area. In this case the second nodal plane has been considered as the reference fault and the Saravan fault is earmarked as the receiver. The Coulomb stress transfer is calculated by considering the receiver fault with an optimally oriented plane for depths of more than 35 kms. The reference fault with the second nodal plane geometry shows a good fit between the regions with increasing static stress and the location of focal points of three deep aftershock events. The results of this study indicate that Saravan fault system was influenced by Gosht earthquake. The occurrence of three aftershocks with low focal depths and the correlation of their epicenters with the regions of increasing static stress indicate Saravan fault was influenced by Gosht temblor. Considering relatively low Coulomb stress variations in the receiver fault model with strike-slip geometry, it can be deduced the transverse faults of the Saravan fault system are less affected by the temblor. The occurrence of three deep aftershocks is in correspondence through the second nodal plane geometry of reference fault with an optimum normal receiver fault. Also, in this study it was found that the nodal plane of 238/56/-102 is more probable as the causative fault of Gosht earthquake. However, it is not possible to determine the earthquake-causing fault by using the focal solution. In particular, because of Gosht earthquake hypocentral depth and tectonic setting of the area, morphological evidences cannot be used to determine the earthquake fault. Therefore, in this study, we are able to determine the earthquake causing fault from the nodal planes by estimating Coulomb stress transfer technique and spatial distribution pattern of aftershock events. It is worth noting that according to Anderson’s theory, the mentioned nodal plane can also be the causative fault of the earthquake.
    Keywords: Coulomb stress change, Coseismic stress, Aftershocks distribution, Makran, Natural disasters
  • Mohammad Mehdi Hosseinzadeh, Somaiyeh Khaleghi, Faraz Vahedifar Pages 41-62
    Introduction River bank erosion has an important role in the instability and damage to agricultural lands and facilities around the rivers and it is a significant source of sediment in fluvial systems. The river bank protection against the erosion is considered as one of the main objectives of river improvement in sustainable development of water resources. The erosion of the river banks is causing damage to agricultural land, damage to structures such as bridges and roads, widening of stream channel and environmental issues considerably. Bank erosion is a major cause of non-point pollution of water resources and increased sediment load in many rivers. Not only increasing banks erosion does increase the sediment load but it also causes river instability and changing flow and channel pattern. Thus, during the recent decades, sediment load and river banks have been created a large concern in the world and the large sums have been spent to stabilize banks. Hence, river bank erosion and channel changes are social, environmental and economic issues that often cause irreparable damage to people and infrastructure in the river banks.
    Material and Methods Qaranqoo chai catchment (upstream of Sahand dam) is located on the southwestern of Hashtrood city (located in 37° 43 to 37° 20 northern latitude and 46 58 to 46 28eastern longitude). The catchment is located on the east Azerbaijan province.In this reach, we used Bank Erosion Hazard Index (BEHI) and Near-Bank Stress (NBS) to predict annual bank erosion in QaranqooChai River. Therefore, nine cross-sections were selected and some parameters were measured for BEHI, parameters such as bank full width, average bank full height, root depth, root density, bank angle, surface protection, and bank material and stratification bank were measured. Bank full height is the distance from bank toe to bank full stage elevation. Bank height divided by bank full height gives a bank-height ratio. Rooting depth is measured from the top of the bank to the bottom of vegetal rooting. Rooting depth is then divided by bank height to get root-depth ratio. The weighted root density calculation begins with a visual estimate of root mass, per unit volume of soil. Bank angle is the angle of the bank face along the elevation plane of the bank. Surface protection is estimated as the percent of bank covered by vegetation, woody debris, boulders or manmade materials. An open bank face has 0% protection while a fully vegetated bank has 100% surface protection. Bank material may affect a bank’s susceptibility to erosion. If bank material is medium or large cobble, ten points are subtracted from the total BEHI score. Five to ten points are added for gravel, a mix of gravel and small cobble, or a mix of gravel and sand. Sand, or a predominantly sand mixture requires the addition of ten points. No adjustment is made for cohesive silt or clay bank material. Banks of bedrock or boulder are always scored as to be very low. Indeed BEHI incorporates bank variables that are factors in entrainment, surface erosion and mass erosion. These variables are bank–height ratio, root–depth ratio, weighted root density, bank angle and surface protection. Variables have empirical values that are in turn, converted to index values and summed for a total BEHI score. Scores are adjusted by bank material and bank material stratification. BEHI scores are then categorized by erosion potentials. A greater score indicates greater erodibility.
    2- NBS: Near-Bank Stress (NBS) assessment is important in predicting erosion so that it is associated with energy distribution in channel cross-section spatially stream banks and this disproportionate distribution of flow energy can lead to bank erosion. In NBS method, two levels were used (level 2 and level 5).Ratio of radius curvature to bankfull width (Rc/Wbkf), ratio of near-bank maximum depth to bankfull mean depth (dnb/dbkf).
    Results and Discussion According to NBS method and level2, the erosion ranged from moderate to extreme in all of cross-sections except the cross-section 7 (low). Also according to level 5, the erosion was very low in the cross-section one and was extreme in the cross-section two and was low to moderate in the other cross-sections. The results of BEHI method showed that both of right and left banks have erosion so that the erosion risk was moderate to very high in all of the right banks of the cross-sections and was only very low in the cross-section 4 and also the erosion risk of the left banks have been estimated to be very low to extreme in the cross-sections.
    Conclusion According to the results of both models, in general erosion in the period under study is the important factor at sediment production in QaranqooChai river and bank erosion risk. Also, both methods used to analyze and evaluate this type of erosion show that in general, due to the exacerbation of the hydraulic stress on the external side the amount and risk of erosion for the outer sides of the arches in the area of the meandering river pattern is more than the opposite side.
    Similarly, the degree of risk of erosion is reduced on both sides of the banks in the middle section of the studied reach. In the last section of the studied reach, the risk of erosion is increased by both models. This study showed that the river pattern, vegetation, and marginal materials play a crucial role in maintaining the bank stability in this area. Based on field observations, the results of the model of the Bank Erosion Hazard Index (BEHI) in the QaranqooChai River is more consistent with reality.
    Keywords: erosion, Channel changes, NBS, BEHI, Qaranqu Chai river
  • Rasoul Heidari, Younes Gholami, Zahra Salimi Pages 63-80
    Introduction Communities around the world are increasingly affected by disasters caused by natural hazards, conflicts and humanitarian emergencies or man created disasters. These disasters often happen in unexpected forms, intensity and places which, in practice, makes any prevention impossible. Many people around the world lose their life because of the natural disasters, while the survivors will remember these bitter experiences. In this sense, our country is among the ten vulnerable countries in the world. During the past 90 years, 12,000 people in the country have lost their lives as a result of disasters and the highest number of casualties (76 percent) has been caused by earthquake. The old areas of the city are vulnerable places. On the one hand, in terms of environmental hazards, specially earthquake, and functional, environmental, social and economic abnormalities on the other hand; and requires detailed, comprehensive, informed and planned intervention to organize them.Increasing the Resilience of cities against natural disasters, especially earthquake, is effective in reducing losses and in the recovery period of the communities. Physical Resilience is one of the influencing factors in the resilience of communities, through which influencing physical and geographical features of societies can be evaluated during disasters. Bushehr is a seismic area, because it is located in the Zagros region, on the edge of Zagros; and also Zagros fault passes Bushehr and it is near to Borazjan. There are some faults which are active and sometimes cause damage. There are some areas in the old regions of Bushehr with high vulnerability against natural disasters (particularly earthquake) which lead to increased vulnerability of their residents when catastrophe occurs. Low quality of the buildings leads to little Resilience against natural disasters, which increases the vulnerability of these areas. In fact this question is posed: how are the physical sub-criteria in old areas of Bushehr? As the old areas of Bushehr are vulnerable, Resilience is a factor in risk reduction and enhancing capacity in these areas. This study aims to identify effective factors in physical Resilience, and to quantify and compare physical sub-criteria in Resilience factor in the old areas of Bushehr.
    Material and Methods This study is a descriptive-analytic one and its data collection tool was a questionnaire. Here, first the conception of Resilience according to the library studies (articles and books) and then physical indicators are introduced. The characteristics of this study are: availability, Resilience, quality of the buildings, and outdoor areas. Cochran formula was used to determine the sample size. 381 questionnaires, consisting of general and specific Likert-scale questions, were handed out among the residents of these areas. The reliability was calculated by Cronbach’s alpha and it was .81 which is high. To analyze the information related to resiliency of old areas, structural equation modeling and statistical analysis methods were used. They were calculated by AMOS software. To get the required map, GIS software was applied.
    The Scope of the Study Bushehr is in the south of Iran. Its neighboring provinces on the north are Khozestan and parts of Kuhgiloye & Buierahmad. It is a coastal city on the north and east of the Persian Gulf, and its eastern neighboring province is Fars. It has a 625 kilometer water border with the Persian Gulf. Its population in 1390 census was over 195,222 (General census of population and housing, 1390). The total area in legal lands is 8289 hectares, 1880 hectares of which is urban area. The rest of the land is for metropolis applications (City planning consulting engineers, 1383). Bushehr is about 25359 square kilometers which contains 5.1 percent of the country and is the seventeenth big province in our country. Its population includes people in old areas of Dehdashti, Kutis, Behbahanis, Shanbadi and old neighborhoods of Aliabad, and Jafari. In addition to local residents in the old areas, there are also Afghan refugees.
    Results and Discussion To examine the hypothesis, the status of physical Resilience in old areas of Bushehr was investigated based on the results of structural equation modeling analysis. Regression analysis of most physical indicators showed a fairly appropriate significant level and also the ratio of critical point and standard error were low. It was shown that the quality of buildings had the most significant effect on physical Resilience against earthquake, among other physical indicators of old areas in Bushehr. According to the results, infrastructure Resilience indicator had the strongest effect on physical Resilience (75 percent). Therefore, the above mentioned hypothesis was rejected.
    Conclusion Physical Resilience is one of the effective factors in the resilience of societies, through which the status of the societies in physical and geographical aspects can be evaluated during disasters. The method used in this study was descriptive analytic approach; therefore, library studies and field surveys were utilized. The population of this study was residents of old areas in Bushehr. 381 questionnaires were handed out in these areas and the variables were analyzed through SPSS and AMOS software. The required maps were obtained through GIS software. It was hypothesized that among the physical indicators of old areas in Bushehr, the quality of buildings has the greatest effect on physical Resilience against earthquake. However, the results showed that infrastructure Resilience indicator had the greatest effect (75 percent). The results showed that the status of the Resilience in old areas of Bushehr is not good in terms of physical indicators.
    To increase the Resilience in these old areas, the following points are recommended: Identifying the scope and intensity of inherent challenges which make our city vulnerable to natural disasters Identifying a set of small pieces of lands in old areas in order to make parks, to increase the access to open areas Identifying some big parks in the city in order to create central rescue stations and to equip them Widening the narrow pathways to prevent increasing urban density along the narrow pathways Applying rules for retrofitting old buildings and increasing the safety of new buildings
    Keywords: Bushehr, Old area, Physical resilience, Structural equation modeling, Vulnerability
  • Mohammad Daraei, Behrouz Sari Saraf, Ali Mohammad Khorshiddoust, Peyman Mahmoudi Pages 81-96
    Introduction
    Global warming and climate are two of the most important environmental challenges around the word. Agricultural sector heavily depends on climate changes. Climate, as the main factor of time, place, production resources and efficiency, has the main effect on agricultural activities. The date of first zero-degree temperature in the fall and its last occurrence in the spring are important. This information is useful in determining suitable species for planting. Global warming has caused changes in the agricultural climatic indices such as the date of occurrence of late spring and early fall frosts. The results of the studies done by researchers in Iran and various regions in the world in recent and ensuing decades represent movement of the occurrence of fall frosts and the last spring frost toward early winter and late winter, respectively.
    Material and Methods
     The study area with latitude of 25 and 40° 00' N, longitude of 44 and 64° 00' E, and with an area of 1,648,195 square kilometers is located in IRAN. The study data consisted of two groups of observational and simulation data. Observational data includes data such as precipitation, radiation, daily maximum and minimum temperatures of 43 synoptic stations in various regions of Iran with full thirty-year (1981-2010). All data are collected from Iran Meteorological Organization. Simulated data of two future periods (2046-2065) and (2080-2099) by using the downscaling output of the two global climate models of GFCM21 and HadCM3 made the highest efficiency and the lowest simulation error in the temperature parameter estimation, being generated based on emissions scenarios (B1, A2, A1B) in version 5 of LARS-WG second group of data.
    The Kolmogorov Smirnov Fitness test was used to estimate if probability distribution of generated data is close to the probability distribution of the monitored data of the stations under investigation. Mean and standard deviation of the data were analyzed using paired t-test and their significance was statistically significant at 0.05.
    In this research, bootstrap method was used to investigate uncertainty. Bootstrap method is used to estimate the accuracy of estimators during independent observations. To calculate the confidence interval using bootstrapping method in SPSS software, at first, the monthly minimum time series of 30 years of stations (1981-2010) was prepared using Lars baseline and the range, mean and standard deviation of the monthly minimum temperature of each station were calculated at 99% level and compared with the mean and standard deviation of the minimum temperature of the observed data. If the estimated values of the models are within the confidence range of the observed data, it indicates the confidence in the desired level of trust and, if it is outside the range, it indicates the uncertainty to the estimated value.
    Results and Discussion The validity of the Lars model in the simulation of the minimum temperature of the temperature with k-s test indicates that there is no significant difference between the simulated and the monitored data. Using T- test indicates that the differences except Bojnourd station in January, the station Bushehr and Shahr-e kord in March, Esfahan station in February and Zahedan station in August are not significant at 0.05 levels. In general, the LARS-WG model has an acceptable ability to simulate the minimum temperature data of the studied stations in Iran and the existing error is random.
    The uncertainty analysis shows that the average of minimum temperature of months in all stations is 72.7% in the confidence range, but the standard deviation is 6.6% in the months in the confidence range. The results show a weakness of the model in estimating standard deviations. Two models and three scenarios are used to reduce uncertainty. Implementing several models and scenarios creates a wide range of analyses. In so doing, we can minimize uncertainty in the production of future weather data.
    The results of the study indicate the movement of the first fall frost and the last spring frost in Iran is toward early winter and late winter, respectively, so that the first fall frost in the period 2046-2065 based on the GFCM21 model and the emission scenarios B1, A2 and A1B, will occur 13, 8 and 7 days later and in the HadCM3 model, and it will occur 9, 8 and 7 days later, respectively. In addition, in the period 2080-2099, based on the GFCM21 model and the scenarios B1, A2 and A1B, it will occur 18, 21 and 9 days later and in the HadCM3 model, it will occur 16, 21 and 9 days later, indicating a positive trend compared to the period 1981-2010. The greatest movement is observed in Khorramabad, Rasht and Gorgan stations. The changes in northeastern stations of Sabzevar and Semnan, the southern half of the country stations of Kerman, Bam and Abade, and most northwestern stations are less than other regions.
    The last spring frost in the central climate based on the GFCM21 model and the emission scenarios B1, A2 and A1B will occur 16, 15 and 9 days earlier, and in the HadCM3 model, it will occur 13, 14 and 11 days earlier, respectively. In the 2080s, (2080-2099), the change based on the above-mentioned scenarios in the GFCM21 model will be 20, 22 and 13 days and in the HadCM3 model, it will be 20, 27 and 16 days, respectively. The most negative trend will be in Gorgan, Rasht, Ardabil and Shahr-e Kord stations. Khoy, Qazvin, Bam and Kashan will have the least negative movement.
    Conclusion
     The results observed in this study are consistent with the results of many previous studies investigating changes of date of the beginning and end of spring and fall frosts in Iran and other parts of the world and indicate the movement of the occurrence of the fall and spring frosts toward the winter frosts. Firstly, this time movement leads to reduced frost period and reduced production of rain fed wheat, and secondly, along with increasing length of the growing period, it increases evapotranspiration, drains soil moisture, reduces the flow of the hydrologic cycle change, and increases the plants’ need for water resulting in increasing use of water. These changes and their adverse effects could be a threat to achievement of sustainable development in our country. Thus, increasing awareness of how changes occur in the spatiotemporal distribution of frost indicators requires further studies and considerable attention in order to adopt strategies compatible with changes, particularly in Iran, which are more exposed to their destructive consequences.
    Keywords: Climate change, First fall frost, Last spring frost, LARS WG model, Iran
  • Samira Jafari Azar, Gholam Reza Sabzghabaei, Mortaza Tavakoly, Soolmaz Dashti Pages 97-119
    1. Introduction Wetland ecosystems are stable ecosystems on the earth providing considerable ecosystem characteristics. Although remarkable advances have been observed in the quantity and valuing some key ecosystem products and the services provided by these habitats, there are still some major challenges with the lack of sufficient knowledge about the relationship between the changes developed in the structure of the ecosystem and the performance of these ecosystems in providing services being the greatest challenge. Based on this, monitoring the trend of the changes in wetlands and their surrounding lands can be effective in the management of these valuable ecosystems. Investigating the environmental risk is a suitable instrument for evaluating and ensuring understanding of the relationships between stressor factors and environmental effects especially in wetland ecosystems. In general, application of methods of evaluating environmental risk is one of the important tools in studying environmental management along with identifying and mitigating potential environmental damaging factors in wetland regions in order to achieve sustainable development. Today, multi-criteria decision-making methods are employed in evaluating the risk in many studies. Examining the background of applying multi-criteria decision-making methods in risk evaluation indicates that these methods have been used in different cases either alone or together with other methods for risk evaluation. This research has been conducted with the aim of identifying the factors of destruction and threat of the Shadegan International Wetland, Alomieh Estuary, Moussa Estuary and their analysis through multi-criteria decision-making methods in order to ordain efficient rules and adopt suitable mechanisms in confrontation with destructors and present managerial solutions to lower the consequences of these factors.
    2. Material and Methods In the first phase of this study, to identify and screen the main criteria of project selection, Delphi method was used. In this study, the panel of interest was determined based on a combination of experts with different expertise and out of a sample of 20 individuals, in which experts with various expertise gave a score from 1 to 5 (Likert scale) to each criterion, where the criteria whose mean scores were lower than 3 were removed. In this way, 35 criteria were identified as the most important and considerable risk for Shadegan Wetland and further proceeded to the second phase for prioritization and analysis. In this stage, multi-criteria decision-making methods were used, in which hierarchical analysis process was employed for prioritizing the criteria using Expert Choice 11 software. In order to explain the risk, the concept of ALARP principle was used. The indices of risk evaluation including the impact intensity, incidence probability, and the sensitivity of the receptive environment in environmental risk evaluation of wetlands do not have an equal value and significance. For this purpose, to weight the factors effective in estimating risk level and for prioritization of risk options, the technique for order of preference by similarly to ideal solution (TOPSIS) and Excel software were benefited from for calculations. The spectrum of scoring to each of the indices of incidence probability, impact intensity, and the sensitivity of the receiving environment was chosen from very low (1) to very high (9) based on hour spectrum. Following investigation of the types and frequency of indices along with the method of score determination of these indices, three indices of risk intensity (C1), risk incidence probability (C2), and the sensitivity of the receiving environment (C3) were chosen for risk ranking using TOPSIS model. Next, after determination of risk priority number using TOPSIS, the risk levels were calculated and evaluated using normal distribution method for each risk. To determine the degree of risk-taking, risks are organized in a descending order, where the elements of the number of the class and the length of the class are determined based on Relations 1 and 2 (n is the number of risks). Next, the risks are categorized based on these classes. Considering the concept of ALARP, the risks under investigation are divided into high risks, medium risks, and low risks. In this study, considering the number and length of classes, the studied risks were categorized in six levels (i.e. critical, intolerable, considerable, medium, tolerable, and trivial risks).
    1)The number of classes=1.3 log (n)
    2)The length of the classes= the greatest risk value - the smallest risk value/the number of classes
    3. Results and Discussion In the first step, the final indices of the wetland's environmental risk were identified and the development of hierarchical tree and classification of the risks threatening wetlands along with their incidence probability in two groups of natural and environmental criteria was performed. Eventually, the final weight of criteria resulting from paired comparisons was obtained in Expert Choice 11 to achieve the score of incidence probability of each risk. Based on the results, among the natural, social, economic, physiochemical, Biological, and cultural criteria, drought and climate change, discharge and disposal of waste in the wetland, dam construction, oil contamination, existence of nonnative species, and application of unauthorized equipment were of high priority. The results obtained from ranking the risks threatening Shadegan Wetland using TOPSIS suggest that drought and climate change, water withdrawal in the upstream and water development plan, dam construction in the upstream and oil contamination, industrial wastewaters, commuting of launch boats, floats and boats, nonnative species, agricultural wastewaters, construction of industries and factories within the wetland range, and urban and rural wastewaters were of the first to tenth priority, respectively. Drought and climate change, water withdrawal in the upstream (water development plan), dam construction at critical level and oil contamination, industrial wastes and commuting of launch boats, floats and boats lied within the intolerable range for wetlands.
    The results of investigating the physiochemical parameters of water using Hilsenhoff index indicate that the factors of contamination of Shadegan Wetland that are of significance include entrance of household wastewaters of the villages around the wetland, followed by the wastewater of cane sugar and steel industries. Over the past few decades, the wetland's water regime has undergone major changes in the quantity and quality along with seasonal changes in response to implementation of irrigation development plans at large scales in the upstream of the river's basin. It is estimated that with the development of irrigation system in the basin, around 1200-1500 million m3 of the river's water resources are used for producing crops. This figure is twice the extent of water consumption since the 1991s. Among the factors that have caused destruction and manipulation in the lands within Shadegan wetland range are development of Shadegan city and the surrounding villages, changing wetland land use to agricultural lands, construction of Shadegan-Abadan Road, Shadegan-Imam Khomeini Port (Chamran City), Shadegan-Ahwaz Road, and Abadan-Ahwaz, which go through the middle part of freshwater in the wetland. Similarly, Shadegan Darkhovin's road, development of industrial city or Imam Khomeini Port or Shahid Chamran, development of cane sugar lands together with different agro-industries, construction of nuclear plant, construction of dam in river route Jarahi to Shadegan Wetland one in Ramshir town and the other in Jarahi village, Shadegan Steel industries (under construction), Shadegan Industrial Town, Imam Khomeini Port Industrial Town, Shadegan Petrochemicals (under construction), the tourism station of Shadegan Wetland, wetland land use change to agricultural lands, passage of oil pipes and construction of high-voltage masts along with embankment in the wetland, development of urbanization in Imam Port and existence along with construction of numerous waterfronts within the range of Moussa Estuary. All of these human constructions have caused fragmentation of the habitat.
    Recent droughts have caused the drying of around 80% of vegetation populations along with emigration and fatality of about 40% of local cattle. Investigation of the extent of changes in the area of Shadegan Wetland in 1990, 2000, 2003, and 2011 represents 6% reduction in the area of the wetland over these years. The area of the wetland in 1990 and 2000 was the highest and lowest, respectively, due to incidence of severe drought in 2000.
    In this study, similar to the study done by Jahed Manesh (2014) together with Jozi and Shafiei (2009) for identifying the risks, Delphi method was used. For weighting the environmental and natural risks and their sub-criteria, similar to the study by Makvandi et al. (2013), Jozi and Shafiei (2009), Rahimi Balouchi et al. (2013), etc. AHP method was employed. For risk ranking through TOPSIS method, unlike Makvandi et al (2013) who used 4 indices of ranking, here similar to Jahed Manesh and Rahimi Baluchi and Malek Mohammadi, three indices were used for ranking. Overall, the results indicated that same as this research, wetland ecosystems are subject to many threatening factors, resulting in ecological imbalance and abnormal appearance of the wetland, putting the wetland entity into danger of extinction in terms of fauna and flora.
    4. Conclusion Today, for assessment of environmental risk, various methods are used, each of which has positive and negative points given the studied environment and the conditions governing it. Therefore, one cannot reject or approve one method with total confidence. By employing novel methods in risk evaluation, the intensity of risk incidences and, in turn, the damages and losses incurred to the environment can be prevented or at least mitigated. Further, it is also possible to move in line with proper and optimal management of environmental resources, especially wetlands and with sustainable development. Overall, one can attribute the root of Iran’s wetlands problems to economic poverty, scientific and cultural weakness, and greed, with the results being weakened biodiversity, services, and functions of the country’s wetlands together with economic, social, and cultural disorders. The best approach for integrating wetland science and evaluating risk that could improve risk evaluation process in wetland ecosystems is ecosystem-based approach. Ecosystem management of wetlands can be implemented through developing a managerial plan to decrease major threats in wetland regions. In general, management of coastal regions and especially marine coastal wetlands includes organization of developmental process through interdisciplinary planning. In other words, marine-coastal regions are one of the natural systems requiring adoption of novel managerial methods for achieving sustainable development. Overall, integrative management of coasts can be regarded as a dynamic process in developing a logical and plausible balance between government, society, and culture in achieving sustainable development in marine-coastal regions.
    Keywords: Environmental risk assessment, International wetlands, MCDM
  • Mohasen Janparvar, Reyhaneh Salehabadi, Seyedeh Samireh Hosini Pages 121-141
    1. Introduction Nowadays, by formation of governments, control and protection of the territories of countries for establishment of low and security has had a prominent place, and governments in various ways have tried to control their boundaries and territories, which construction of the wall of China, Hardin, Gorgan wall and ... have been evidence of this claim in the past. Over time, use of boundary walls with the closeness and dependency of countries and governments to each other and the emergence of issues such as globalization and the world without boundaries, for the decades of the second half of the twentieth century the importance and place of boundary and borderline put under their radius. But the process of developments in the contemporary world has been such that after two decades the collapse of the Berlin Wall and the formation of topics such as globalization, the world without boundaries, the end of geography, and ... the reversal process have been shaped in the contemporary world. This process has been such that since 2000 almost 25 boundary walls have been created by governments in different parts of the world. Islamic Republic of Iran, in the meantime according its long boundaries and the boundary issues that have harden the country's boundary control and management, such as unbiased neighbors, lack of cooperation to control boundaries, and ... has attempted by the policy of blocking boundaries of the country through the creation of wall along the boundaries of the country, provide effective control and management of boundaries of the country in areas such as Iran-Pakistan boundary, Iran and Afghanistan, Iran and Iraq (northern Iraq). The implementation of this plan at a high level to manage and control better the boundaries has comparative advantages that are not relevant here, but the discussion that has been less attention and will discussed in this article is the challenges posed by the implementation of this plan in form of environmental hazards (natural and human) that will be dealt with less. In order to be able more precisely describe the environmental hazards resulting from boundary obstruction, is considered the case study in the Iran's boundary in Sistan and Baluchistan province.
    2. Study area & Material and Methods Sistan and Baluchistan province is one of the largest provinces in the country and its area is 187502 km2, equivalent to 11.5% of the country's total area. In the North is limited to the south Khorasan province, in the south to the Oman Sea, in the east to Pakistan and Afghanistan, and in the west to the provinces of Hormozgan and Kerman. The Sistan and Baluchistan region according its geographical position is affected by numerous atmospheric flows in one hand, such as the Indian sub-continental wind and, consequently, the monsoon rains of the Indian Ocean, and on the other hand is affected by the medium-tidal pressure, which the extreme heat is the most significant climatic phenomenon of it.
    The general method of this research is descriptive-analytical and library and internet resources are used to collect information. The factors are categorized according to the importance of each factor from most important to the least important. The rank of power is one of the ranking methods in which first we rank the criteria and then use the formula (n-rj 1) 2 to rank the criteria.
    3.
    Results And Discussion
    A) Library
    Discussions
    1. Natural hazards arising from the construction of the boundary wall
    As the boundary wall acts as a physical barrier to entry of unauthorized persons into the country. It should be acknowledged that the obstacles created by mankind, in addition to the positive qualities, have negative aspects. For example, the boundary wall of Sistan and Baluchistan, while preventing unauthorized traffic, also has some environmental risks which will damage the natural ecosystem (plant and animal) of the region and in long run lead to naturally problems. The most important of these risks due to the obstruction of the boundaries in Sistan and Baluchistan province are: - Preventing animal immigration
    - Extinction of plant species of the region
    - Destruction of the ecotourism industry
    - Increased area wind erosion
    B) Human hazards
    Boundary walls, not only increase natural hazards, but also threaten human security in the boundary areas, which will spread to other parts of the country and in other words, affect the entire country.
    - Cultural-ethnic separation across borders
    - Guide people to unknown spaces
    - Increased tendency to smuggle drugs and weapons
    - Reduce trust in the central government
    - High economic costs
    C) Statistical
    Discussion
    In this research, two groups of natural and human hazards caused by the construction of boundary walls on the boundary of Sistan and Baluchistan have been investigated, which have 9 cases. By using rating technique, can rank these hazards based on the degree and significance of them, first giving them a direct rating and then using the formula ( N-rj 1) 2 scale each one and finally, by dividing the scale of each criterion into the total scales, we list the hazards in the range from the highest to the lowest rank. (In this case: n = total number of criteria, rj = direct rank).
    Table 2: Ranking of factors arising from the construction of the boundary wall
    Hazard Direct rating Scale Standard rating
    Reduce trust in the central government 1 81 0.284
    Cultural-ethnic separation across borders 2 64 0.225
    Extinction of plant species of the region 3 49 0.172
    Preventing animal immigration 4 36 0.126
    Increased tendency to smuggle drugs and weapons 5 25 0.088
    Destruction of the ecotourism industry 6 16 0.056
    High economic costs 7 9 0.032
    Guide people to unknown spaces 8 4 0.014
    Increased wind area erosion 9 1 0.004
    Total 45 285 1
    4. Conclusion One way that countries use to control and manage their boundaries is blocking boundaries by construction of these boundary walls. Despite the benefits of it for some countries, also produce some risks to countries that unfortunately have not been attention. Meanwhile, the Islamic Republic of Iran, by constructing a boundary wall in Sistan and Baluchistan, is trying to control and manage its boundaries in that part of the country more effectively. Although it is not possible to conceal the benefits of such an action, but along with these benefits, some of the hazards from the construction of these boundary walls of the country are problematic, which has been less studied in studies on boundary. The results of the present study are divided into two parts as follows: Natural hazards (environmental): preventing the migration of animals; extinction of plant species of the region; destruction of the ecotourism industry; increased wind erosion.
    Human risks: cultural-ethnic separation across borders; guide people to unknown spaces; increase tendency to smuggle drugs and weapons; reduce trust in the central government; high economic costs
    In general, the construction of boundary walls along the borders of Iran in Sistan and Baluchistan Province can significantly affect the environment of this part of the country due to its fragile ecosystem, and on the other hand, the construction of these boundary walls regardless of the economic situation of the frontier in this part of the country and its dependence on boundary exchanges can provide divergence, distrust of the central government and attract frontiers to organized groups of drug and weapons smuggling.
    Keywords: Environmental hazards, boundaries, boundary walls, Sistan, Baluchistan province
  • Alirea Oliaei, Naser Parvian, Azra Khosravi Pages 143-158
    1. Introduction Water shortage problem has gained new complicated dimensions in a variety of countries located in arid regions of our planet including Iran which has forced the researchers to think of the solutions for this problem. Water resources in the depth of hard formations are considered as one of the most significant resources of fresh waters. On the other hand, there are a wide range of these types of formations in Iran which have attracted a huge amount of studies. Therefore, there is a necessity in studying the baseline of the springs originating from hard formations in optimum managing and exploiting underground waters. Land morphological features are commonly used for preparing underground potential existence maps. Additionally, in aquifers located in hard cracked formations, a variety of parameters including surface topography, lithology, cracking density, ground water feeding rates, land uses, slope classes, drainage patterns, atmospheric status or a group of them are used in order to map moving underground waters.
    In a comprehensive GIS–RS and logistic regression model based research run in Maxent software package environment, this paper determined the maximum amount of parameters which affect spring flooding patterns in hard formations located in Kalat Naderi region through which simulated spring's distribution patterns using GIS, Maxnet software based on logistic regression and measurement in a comprehensive.
    Kalat Naderi watershed is located in Khorasan Razavi province, northeast of Iran between 18'63¬°58 " to "35'79¬°60 of eastern longitude and 09'53¬°37 to "25'32°36 of northern latitude. Geologically, the study area is located in Bojnurd – Shirvan lithology sheets mostly in Koppedagh zone. Stratigraphical history of Kalat Naderi watershed dates back to Ordovician period in Paleozoic and quaternary eras. The studied watershed is 8565 square kilometers of area with 236 and 3069 meters from seed level in lowest and highest points, respectively.
    2. Material and Methods We used 13 parameters (fault density, distance from faults, distance from rivers, land use, profile curvature, tangent curvature, total curvature, surface ratio, mean rainfall, elevation, lithology, geographical aspects and slope degrees) in order to analytically prepare springs existence map layers and verify the maps in the field. Indeed, all of the aforementioned parameters have influence on groundwater infiltration, feeding or harvesting amount. A report of 895 springs located in the study area was gained from Iranian Water Resources Management Office (IWRMO) and regression model in Maxent software environment was used in order to verify the data. Fifity replications and 895 random points were used to model the gathered data. Also, 75% of the selected points were used as the learning points and 25% of the remaining points were utilized to plot the model. It is worth mentioning that lithology, land use and geographical maps were classified based on surface infiltration potentials and spring outcrop entered to the model.
    The other maps were entered to the model in a continuous rasterized format. Jackknife resampling method was used in order to define the importance of each variable on species distribution patterns. Furthermore, ROC curve was utilized to define model's accuracy and efficiency.
    3. Results and Discussion Sensitivity analysis for morphometric factors, jackknife analysis and the logistic regression in Maxent software environment for defining the chance of existence of springs showed that precipitation related variables and lithological characteristics are the most significant factors which directly influence the chance of springs to exist so that the more their frequency are, the more the chance of springs existence. In addition, the results revealed that more porosity of the lithological sheets show a higher chance for the springs to exist. Forests and westward- northward aspects showed higher chance for the springs to exist. A negative relationship was seen among distances from faults and distances from rivers with the chance of springs existence. Also, there is a positive relationship among springs distribution patterns and elevation from see level up to 2800 meters.
    Results showed a decreased chance of springs existence with increased slope degrees due to less infiltration amount. A positive relationship was seen between fault density and the chance of springs to exist.
    Finally, the groundwater potential quality map was classified into four (very low, low, medium and high) classes with 33.03, 14.07, 4.01 and 48.9 percent of the total area. ROC curve showed a high accuracy of 92.3 % for the model.
    Finally, it is concluded that, due to its accordance with the existing data, the model is considered as a suitable method for tracking groundwater tables especially in hard formations which result in a high efficient management for water resources.
    Keywords: Kalat Naderi, Maxent, ArcGIS, Regression, Water resources, Hard formations
  • Masoud Minaei Pages 159-172
    Providing climatic data like temperature in good spatial resolution is a key requirement for many geographical, ecological and bioclimatic research. With this in mind, various related studies use thermal remote sensing images as auxiliary data to enhance the air temperature interpolation outcomes. That’s while normally summer season images are used as auxiliary data and less attention has been paid to winter season acquired images which are often covered by snowy areas. With this in mind, the Snow Covered Area (SCA) extent impacts on air temperature interpolation were investigated. The data used were temperature data and four Landsat thermal images of December 1986 and 1999. To calculate the area of snow cover, band combination and NDSI index were used. Results show that Thermal Co-Kriging (TCK) of December 1986 provide better results with more snow affected thermal image. While in 1999 although different results were obtained but the best selected output did not show impacts of different snow cover area. These results revealed that probably the SCA extent threshold could be different and could be found with more research. Finally, we know that number of our observation stations are too low and considering the Kriging requirements like normal distribution and stationarity are toilsome but we should consider that this problem exists in the regions with low density of gauges and should find a way to enhance the air temperature interpolation in these cases. At the end, using high resolution, Landsat thermal bands improve our ability to explain and visualize local temperature variability into a variety of applications such as deriving temperature dependent climatic variables, species distribution modelling and assessments of fire risk.
    Keywords: Interpolation, Thermal co-kriging, Kriging, Golestan