فهرست مطالب

فصلنامه پژوهش های جغرافیای طبیعی
پیاپی 113 (پاییز 1399)

  • تاریخ انتشار: 1399/08/26
  • تعداد عناوین: 9
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  • علی سوری نژاد* صفحات 351-373

    در سال​های اخیر مقادیر بارندگی و جریان‏های سطحی سی حوضه آبریز ایران نسبت به نیم قرن گذشته به شدت کاهش یافته است. در این پژوهش حوضه‏ های مذکور به ‏عنوان‏ مطالعه موردی انتخاب شده و هدف از اجرای آن ارزیابی اثرهای احتمالی تغییر اقلیم در بارندگی و منابع آب سطحی تجدیدپذیر است‏. برای بررسی این موضوع، مقادیر بارندگی و آبدهی اندازه‏گیری‏شده این حوضه ‏ها از سال 1347 تا 1397 در سه دوره آماری از 1347-1397، 1347-1377، و 1377-1397 طبقه‏ بندی شد. سرانجام، با آزمون‏های آماری t استیودنت، من​- ویتنی، من- کندال گرافیکی روند تغییرپذیری داده‏ ها در سطح اطمینان 95 درصد و 99 درصد با SPSS محاسبه شد. به موجب نتایج این پژوهش، معلوم شد روند بارندگی بلندمدت همه حوضه‏ ها منفی بوده و میانگین حجم جریان‏های سطحی تجدیدپذیر بیست سال اخیر نسبت به میانگین پنجاه سال بین 13- تا 61- درصد کاهش یافته و آماره  U(ti)   همه آن‏ها منفی است. به ‏نظر می‏رسد علت آن تغییر اقلیم است‏. به‏ عنوان‏ مثال، آماره U (ti)  بارش‏ها در حوضه کارون 2.77-، مارون جراحی 2.18-، در کرخه 1.98-، غرب ایران 1.78-، و قره‏سو- گرگان 2.70+ است‏. در مقایسه با آن آماره U (ti)  آبدهی آن‏ها به‏ترتیب 3.35-، 3.07-، 4.51-، 2.87-، و 3.29- است‏.

    کلیدواژگان: آب تجدیدپذیر، بارش، تغییر اقلیم، من- کندال
  • حسین عساکره*، لیلا احدی صفحات 375-394

    آلودگی هوا، به‏ ویژه در کلان‏شهرها، اهمیت قابل توجهی دارد. از عوامل تشدیدکننده این مشکل شهری شرایط جوی و تیپ‏های هوایی حاکم بر شهرهاست. تبریز از جمله کلان‏شهرهای کشور است که با شرایط حاد آلودگی هوا مواجه است. هدف اصلی از این پژوهش بررسی رابطه شرایط جوی و تیپ‏های هوایی تبریز در تشدید آلاینده ‏های هواست. بدین‏ منظور، سه نوع داده استفاده شده است: اول، میانگین داده‏های ساعتی گازهای آلاینده جو جهت بررسی آلودگی جو؛ دوم، میانگین داده ‏های روزانه هواشناسی برای استخراج تیپ‏های هوایی؛ سوم، داده‏ های بازکاوی‏ شده مرکز ملی پیش‏بینی محیط و مرکز ملی پژوهش‏های جوی ایالات ‏متحده امریکا برای وارسی الگوهای جوی توام با تیپ‏های هوایی به‏کار گرفته شد. نتایج بررسی تیپ‏های هوایی توام با روزهای آلوده نشان داد باد غالب جنوب غربی- شمال ‏شرقی با سرعت کم است که حاصل استقرار مرکز پرفشار اروپا و سیبری در شمال‏ غربی و شمال ‏شرقی ایران و استقرار مرکز کم ‏فشار روی دریای خزر بوده است و توام با حرکت هوا از مناطق پرفشار به منطقه کم‏ فشار به‏ صورت ساعت‏گرد و همراه تکوین جریانات جنوب ‏غربی بوده است. روزهایی که آلاینده PM10 به شدیدترین میزان رسیده است بر روی منطقه مورد مطالعه در تراز 1000 هکتوپاسکال مرکز کم ‏فشار و در تراز 500 هکتوپاسکال جریانات مداری حاکم است. باد تراز دریا و 500 هکتوپاسکال به‏ صورت جنوب غربی و غربی است. از آنجا که صنایع در غرب تبریز قرار دارند، کم‏ فشار مذکور در ارتباط با سامانه ‏های مجاور آلودگی صنایع را به مرکز شهر هدایت می‏کند.

    کلیدواژگان: آلاینده ‏های جوی، آلودگی هوا، تبریز، تحلیل خوشه‏ ای، نمایه AQI
  • عادل نبی زاده بلخکانلو*، پرویز ضیائیان فیروزآبادی، علی خدمت زاده صفحات 395-408

    در سال‏های اخیر، افت تراز سطح آب دریاچه ارومیه، بررسی میزان تغییرات آستانه ‏های دمایی، رطوبتی، و تنش خشکی پوشش گیاهی را در منطقه ضرورتی اجتناب ‏ناپذیر کرده است. در این تحقیق، که از نظر روش توصیفی- تحلیلی و از نظر هدف کاربردی است، از داده ‏های سنجنده MODIS به‏منظور بررسی رابطه فضایی NDVI-TS و NDVI-ΔTS برای استخراج زمان وقوع خشک‏سالی کشاورزی از ژوین تا اکتبر سال‏های 2005 تا 2008 استفاده شده است تا شاخص‏های VTCI و WDI که قادر به شناسایی تنش خشکی در مقیاس منطقه ‏ای ‏اند استخراج شوند. نتیجه این تحقیق نشان داد که در هر دو شاخص وضعیت تنش خشکی در سال‏های 2007 و 2008 بیشتر بوده است. همچنین، براساس رابطه فضای NDVI-TS در همه سال‏های 2005 تا 2008 شیب بالایی فضای مثلثی برای لبه گرم منفی است؛ یعنی با افزایش NDVI میزان LST کاهش یافته است؛ درحالی‏که برای لبه سرد شیب مثبت است. همچنین، شیب به‏دست‏آمده از رابطه فضای NDVI-ΔTS برای خط خشک منفی است؛ یعنی خط خشک یا خط حداقل  ETRیک همبستگی منفی با  NDVIرا نشان می‏دهد. درحالی‏که برای خط مرطوب بالاخص در سال 2008 شیب مثبت بوده و در بقیه سال‏ها تغییر محسوسی دیده نمی‏شود. پژوهش حاضر نشان داد مقدار آستانه VTCI برای تنش خشکی در سال 2007 و 2008 شدید بوده است.

    کلیدواژگان: حوضه آبریز سیمینه ‏رود، خشک‏سالی کشاورزی، MODIS، VTCI، WDI
  • علی اکبر گرمسیری مهوار، قاسم عزیزی* صفحات 409-428

    مراکز پرفشار جنب حاره ابعاد ناشناخته‏ای دارند. در این تحقیق، نخست سیر تحول ماهانه پرفشارهای آزورس و هاوایی با استفاده از داده ‏های فشار سطح دریا و مولفه‏ های مداری و نصف‏النهاری باد ارایه شده است. سپس، سطح مقطع قایم جریان واچرخندی، سرعت قایم، ارتفاع ژیوپتانسیل، و واگرایی افقی در موقعیت این سامانه ‏ها تحلیل شده است. داده ‏ها با تفکیک افقی 0.25×0.25 درجه از مرکز ECMWF و نسخه ERA5 در یک بازه زمانی چهل‏ساله (1979 تا 2018) انتخاب شده ‏اند. نتایج نشان داد در جولای جریان واچرخندی و فشار سطح دریا دو عامل اساسی در شکل‏ گیری سلول‏های پرارتفاع در ترازهای زیرین‏‏اند و فرونشست هوا نقشی در شکل‏گیری بیشینه فشار سطح دریا و سلول‏های پرارتفاع ندارد. سلول‏های پرارتفاع در ترازهای بالاتر به سمت غرب تمایل پیدا می‏کنند. صعود هوای گرم و گرمای نهان آزادشده نقشی اساسی در شکل‏ گیری زبانه‏ های پرارتفاع در جناح غربی دارند. اگرچه در جولای جریان واچرخندی و سلول‏های پرارتفاع در ترازهای زیرین از شدت و گرادیان بیشتری برخوردارند، الگوهای استخراج‏ شده از کمیت‏های مورد مطالعه نشان می‏دهند پرفشارهای جنب حاره را نمی‏توان محدود به ترازهای زیرین دانست.

    کلیدواژگان: پرفشار آزورس، پرارتفاع، پرفشار جنب حاره، پرفشار هاوایی، واچرخند
  • نوشین احمدی باصری، علی اکبر سبزی پرور*، مهرانه خدامرادپور، خوان لویئس گررو راسکادو، لوکاس آلادوس آربولداس صفحات 429-443

    تابش سطح زمین (SSR) از مولفه‏ های اساسی در مطالعات هوا و اقلیم ‏شناسی به ‏شمار می‏رود و تغییرات آن تاثیر زیادی در اکوسیستم‏های زیست ‏محیطی زمین و اقلیم مناطق دارد. به‏ دلیل محدودیت در اندازه ‏گیری‏ های زمینی و نیاز به داده ‏هایی با کیفیت بالا، روش‏های مختلفی برای برآورد تابش SSR توسعه یافته است. یکی از مهم‏ترین روش‏های‏ برآورد تابش SSR، مدل‏های ماهواره ‏محورند که با داشتن قدرت تفکیک زمانی و مکانی بالا و دسترسی رایگان می‏توانند منبع جایگزین مناسبی برای مناطق فاقد‏‏ ایستگاه باشند. هدف از این پژوهش، ارزیابی تابش SSR استخراج ‏شده از سه مدل ماهواره‏محور CERES، CLARA، و SARAH با استفاده از اندازه ‏گیری ‏های زمینی در ایران در مقیاس روزانه است. نتایج این تحقیق نشان داد محصول SARAH با اختلاف کمی نسبت به دو محصول CERES و CLARA با ضریب تعیین برابر با 93/0 و خطای RMSE برابر با W.m-2 4/22 در ارزیابی تابش SSR روزانه‏‏ در ایران عملکرد مناسب‏تری دارد. همچنین، بررسی خطای RMABD نشان داد محصولات ماهواره‏ای مورد مطالعه در شرایط آسمان صاف (ماه‏های گرم سال) با مقدار خطای به میزان 5/5، 6/5، و 8/4درصد نسبت به شرایط ابرناکی (ماه‏های سرد سال) به مقدار خطای به میزان 2/12، 4/11، و 11درصد به ‏ترتیب توسط CERES، CLARA، و SARAH توانایی بیشتری در برآورد تابش SSR دارند. تغییرات مکانی تابش روزانه SSR بیانگر آن است که محصولات ماهواره‏ای مورد مطالعه در مناطق خشک و نیمه ‏خشک به ‏ترتیب بهترین عملکرد را نسبت به مناطق ساحلی دارند.

    کلیدواژگان: محصول تابش CERES-CLARA-SARAH، مقایسه ماهانه و فصلی
  • مجید احمدی ملاوردی، ایرج جباری*، امان الله فتح نیا صفحات 445-465

    در سال‏های اخیر پدیده گرد و غبار در استان‏های غربی ایران رو به فزونی گذاشته است و به موازات آن تغییرات محیطی شدید رخ‏داده ذهن پژوهشگران و مدیران را، علاوه بر خاستگاه ‏های خارجی، به خاستگاه ‏های داخلی کشور نیز معطوف کرده است. در این تحقیق سعی شده است، با هدف مدیریت محیط، خاستگاه ‏های داخلی گرد و غبار در استان‏های‏ کرمانشاه و ایلام شناسایی و علل آن بررسی شود. از این رو، در این تحقیق نخست خاستگاه ‏های ‏گرد و غبار با استفاده از تصاویر مادیس، شاخص TDI، و مدل HYSPLIT شناسایی شد. سپس، نقشه‏ های ژیومورفولوژی و تغییر کاربری اراضی تهیه شد و بر روی نقشه خاستگاه‏های گرد و غبار همپوشانی شد تا توزیع و فراوانی خاستگاه ‏ها در هر کلاس مشخص شود. توزیع فضایی خاستگاه ‏های گرد و غبار نشان می‏دهد چند منطقه مهم تولید گرد و غبار در غرب این استان‏ها قرار دارد که شامل نواحی اطراف دهستان ازگله، قصرشیرین، نفت‏ شهر، و سومار در استان کرمانشاه و منطقه مهران، دهلران، و روستای ابوقویر در استان ایلام است‏. بیشتر دود توده‏ های گرد و غبار از مناطقی منشا گرفته‏ اند که دارای ذخایر فراوان رسوبات آبرفتی‏اند و در آن‏ها تغییر کاربری اراضی، به‏ ویژه تبدیل اراضی مرتعی به کشاورزی، اتفاق افتاده است. بنابراین، برای جلوگیری از فرسایش بادی، پدیمنت‏ ها، مخروط‏ افکنه ‏ها، دشت‏های آبرفتی، و دشت‏های سیلابی باید در اولویت برنامه ‏های مبارزه با فرسایش بادی قرار گیرند و از تغییر کاربری اراضی مرتعی به کشاورزی جلوگیری شود. همچنین، با احیای پوشش گیاهی طبیعی در اراضی که تغییر کاربری صورت گرفته است وقوع گرد و غبار در منطقه کاهش خواهد یافت.

    کلیدواژگان: ایلام، تصاویر مادیس، تغییر کاربری اراضی، ژئومورفولوژی، کرمانشاه، مدیریت گرد و غبار
  • محمد آزادی مبارکی، محمود احمدی* صفحات 467-480

    غلظت ذرات معلق (PM2.5) با وضوح مکانی بالا امکان کنترل دقیق کیفیت هوا را فراهم می‏کند، به‏ خصوص برای کلان‏شهرها که دارای تراکم بالای جمعیت‏اند. هدف از این پژوهش برآورد ذرات معلق (PM2.5) و روند تغییرات آن در شهر تبریز است. به این منظور، داده ‏های عمق نوری هواویز (AOD) سنجنده ‏های SeaWifs، MISR، و MODIS طی دوره آماری 1998-2016 برای برآورد PM2.5 استفاده شد. سپس، با استفاده از روش رگرسیون وزن‏دار جغرافیایی (GWR) و کاربست داده‏ های شهری و ایستگاه‏های آلودگی هوا مقدار PM2.5با تفکیک مکانی 01/0 درجه قوسی برای شهر تبریز برآورد شد. برای مطالعه روند و شیب روند از آزمون‏های ناپارامتریک من- کندال و سنس استفاده شد. غلظت PM2.5 تبریز حداقل 29/11 و حداکثر 86/16 µ/m3برآورد شد و مناطق غربی شهر بیشینه مقدار PM2.5 را دارا می‏باشند. میانگین بلندمدت PM2.5،µ/m304/14 محاسبه شد که نسبت به استاندارد سازمان محیط زیست ایران µ/m3 2 بیشتر است. روند PM2.5 کاملا افزایشی است و مناطق غربی شهر از روند شدت بیشتری برخوردار است. مقدار PM2.5 تبریز µm/m3 20/0 year-1 در حال افزایش است که تهدیدی جدی برای شهر تبریز است. بنابراین، می‏توان نتیجه گرفت روش GWR مبتنی بر داده‏های سنجش از دور نسبت به روش‏های موجود تهیه نقشه‏های آلودگی هوا برتری دارد.

    کلیدواژگان: تبریز، ذرات معلق (PM2.5)، رگرسیون وزن‏دار جغرافیایی (GWR)، کنترل کیفیت هوا
  • اصغر مولایی، حسن لشکری* صفحات 481-498

    باد یکی از پارامترهای مهم اقلیم است و به ‏عنوان یک شاخص مناسب می‏تواند برای تغییرات اقلیمی و الگوهای مرتبط با جریان هوا به کار برده شود. هدف از این تحقیق بررسی روند تغییرات بلندمدت سرعت باد در ایران مرکزی است. به این منظور، از داده‏ های سرعت باد پایگاه بازتحلیل‏شده ECMWF نسخه ERA-Interim با تفکیک مکانی 75/0×75/0 درجه قوسی و داده ‏های هفت ایستگاه سینوپتیک طی دوره آماری 1980-2017 استفاده شد. برای درستی‏ سنجی داده ‏های پایگاه ECMWF از روش‏های R2، MBE، و RMSE و برای محاسبه روند از آزمون ناپارامتریک من- کندال (M-K) استفاده شد. نتایج نشان داد پایگاه ECMWF از دقت مناسبی برای برآورد سرعت باد برخوردار است؛ به‏ طوری ‏که مقدار R2 در ایستگاه ‏های مورد مطالعه بین 72/0 تا 95/0 متغیر است. متوسط سرعت باد در ایران مرکزی m/s19/3 محاسبه شد. کمینه سرعت باد در ماه ژانویه با 01/2 و بیشینه سرعت باد با m/s 95/3 در ماه ژلای محاسبه شد. به‏ترتیب بیشترین شدت روند افزایشی و کاهشی سرعت روند سرعت باد در ماه‏های مارس (نمره Z، 91/4) و دسامبر (نمره Z، 73/2-) محاسبه شد که در سطح آماری 01/0 معنی ‏دار است. همچنین، بیشینه پهنه ‏های روند افزایشی و کاهشی سرعت باد به ‏ترتیب در ما ه‏های فوریه و ژانویه به‏دست آمده است.

    کلیدواژگان: آزمون ناپارامتریک من- کندال، ایران مرکزی، پایگاه ECMWF، سرعت باد
  • منصور پروین* صفحات 499-514

    حوضه آبخیز کرند غرب در شمال ‏غربی زون زاگرس چین‏خورده در غرب استان کرمانشاه واقع شده است. قرارگیری حوضه مورد مطالعه در زون فعال زاگرس و وجود گسل کرند در محدوده آن سبب فعال‏ بودن حرکات تکتونیکی در این حوضه آبخیز شده است. بنابراین، ارزیابی و برآورد تکتونیک فعال این حوضه و مخاطرات ناشی از آن لازم و ضروری است‏. هدف از پژوهش حاضر ارزیابی و برآورد تکتونیک فعال حوضه کرند غرب براساس تحلیل ویژگی ‏های شبکه زهکشی است‏. بر این اساس، نخست محدوده حوضه مورد مطالعه و شبکه ‏زهکشی آن استخراج شد. سپس، با استفاده از شاخص‏های مورفومتری و ژیومورفیک (‏Da، ga، R، Rb، Rbd، Af، T، Bs، SL، و S)، که مختص تحلیل شبکه زهکشی بوده، تکتونیک فعال حوضه مورد مطالعه ارزیابی شد. در ادامه نتایج شاخص‏های مورفومتری و ژیومورفیک با هم مقایسه شد و با شواهد ژیومورفیک موجود در حوضه کرند غرب تطبیق داده شد. نتایج حاصل از شاخص‏های مورد استفاده نشان می دهد ناهنجاری‏های سلسله ‏مراتبی در شبکه زهکشی حوضه کرند غرب تحت تاثیر تکتونیک فعال است‏. این ناهنجاری به‏ صورت تعداد بسیار زیاد آبراهه‏ های رتبه 1 مشخص شده است. نتایج شاخص‏های ژیومورفیک نیز بیانگر بالاآمدگی ساحل چپ رودخانه اصلی به‏ علت جنبش راندگی کرند بوده و این امر سبب کج‏شدگی حوضه و عدم تقارن شبکه زهکشی در حوضه مورد مطالعه شده است. یافته ‏های پژوهش بیانگر آن است که ‏فعالیت ‏های تکتونیکی در حوضه کرند غرب به ‏صورت بالاآمدگی کلی حوضه و نامتقارن ‏بودن آن است‏. نتایج شاخص‏های مورفومتری و ژیومورفیک و تطبیق آن‏ها با شواهد ژیومورفولوژی تکتونیک فعال بیانگر فعال‏بودن تکتونیک در حوضه کرند غرب است‏.

    کلیدواژگان: تکتونیک‏ فعال، حوضه کرند غرب، شاخص‏های ژئومورفیک و مورفومتری، شبکه ‏زهکشی، شواهد ژئومورفیک
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  • Ali Sourinejad * Pages 351-373
    Introduction

    Climate change as one of the most important environmental hazards around the world has led to the emergence of the worst climatic conditions, such as: heat waves, changes in the temporal and spatial distribution of atmospheric dispersal patterns (heavy rainfalls), prolonged periods of droughts, severe floods, severe storms , Dust particles, etc., and has, in recent years, left unhealthy effects on the hydrological cycle and renewable water sources (IPCC, 2016). According to the IPCC, the global average temperature in 2016 is about 1.3 degrees Celsius more than the recent 100 years because of uprising the greenhouse gas emissions (IPCC 2017). In Iran, during the period from 1970 to 2004, the average annual temperature ranged from 1 to 2 degrees Celsius (IPCC 2014). Currently, due to rising temperatures and reduced rainfall in recent years, fresh water resources have fallen across the Iranian catchment areas and in some places have led to the drying rivers. In this way, the annual and balance of water supply's with the amount of renewable water has been interacted and has led to increased demand for agricultural, drinking and industrial water in this paper. To query this, 30 watersheds throughout Iran have been selected as a case study with the aiming to assessing the potential impacts of climate change on renewable water sources.

    Materials and methods

    In this case study, using the data of 2113 meteorological and 1116 hydrometric stations of the Ministry of Energy and the Meteorological Organization, the values of the time series of rainfall data and the annual volume flow of all rivers in 30 catchments were selected using Excel software from 1968 to 2018. Subsequently, rainfall and runoff data were classified into three statistical periods of 50, 30 and 20 years (respectively from 1968 to 2018, 1968 to 1997, and 1998 to 2018). Finally, using parametric statistical tests T-test and non-parametric Mann-Whitney and Man-Kendall mutation variability in the time series of these periods, at 95% confidence level and 99% confidence level, SPSS software was evaluated and verified.

    Results and discussion

    In this research, the results of parametric and nonparametric statistical tests to reveal the mutation and verification of the trend in the long-term variations of rainfall data and annual flow volume of all rivers in 30 catchments are presented in Table 1. In this case study. Table (1) Statistical values of T-Student, Mann-Whitney and Mann-Kendall tests of rainfall (R) and surface flow (SF) 30 of catchment area Iran. In this table, the results of T-Student and Mann-Whitney tests at 95% and 99% confidence levels show that significant leakage has occurred in the catchment area of Lake Uremia in reducing rainfall and annual river flow volumes, as well as in basins there is also a significant mutation in rainfall in decreasing and increasing order, respectively. In the other basins of Aras, Tallesh-Anzali, Lahijan-Noor, Harraz-Neka and Atrak, although the Z (R) statistics of the Mann-Whitney test show a negative trend, but Z (R) precipitation is not significant and not confirmed, In comparison with rainfall, annual volume fluxes in these basins are more intrusive and Z (SF) is significant, which is confirmed by the mutation. According to the results of these tests, across the catchment areas of Hamoun, Serakhs, West Frontier, Karkheh, Dez-Karoun, Maroun Jarrahi and Zohreh, Kol-Mehran and Southern Coastlands, Bandar Abbas-Sedich, Salt Lake, Gavkhoni, Tashk-Bakhtegan, MeHarlow, Siah-kuh and Rigzarin also have a significant mutation in reducing the rainfall and annual volume flow rates, so the Z (R) and Z (SF) statistics of the Man-Whitney test in these basins Is negative and the result of the mutation is confirmed, if the T (R) and T (SF) statistics obtained from the T-test are positive for all of them. The results of my Kendall test's revelation in Table 1 show that in most of the country's catchment areas from 1968 to 2018, although the process of rainfall variability is more strongly negative, but their U(ti) R statistics are significant be. Therefore, this phenomenon can be related to the possible impacts of climate change. For example, the minimum U(ti) R statistics in the Dez-Karoun basins is -2.81, Maroun Jarrahi -2.18, Karkheh -1.98 and in the western border region is -1.78, with a significant negative trend And the maximum U(ti) R in the Gherahso-Gorgan basin was + 2.70 with a positive and significant trend. In the case of U(ti) SF, the volume of surface Flow of these basins is -3.35, -2.87, -3.07, -4.51 and -3.29, respectively, and has a decreasing and meaningful trend. Also, according to the results of this test, it can be seen that in all the country's catchment areas, the variability of rainfall and annual volume flows from 1968 to 1997 (the first statistical period selected for 30 years) compared to the time series from 1968 to 2018 (For 50 years), the U(ti) R and U(ti) SF statistic were 95% and 99% confidence levels less than ± 1.96 and ± 2.58, respectively, and were not significant Be These conditions also apply to the rainfall from 1998 to 2018 (the second period of statistical selection). The trend of fluctuation of surface Flow from 1998 to 2018 (for 20 years) has had a relatively moderate decrease compared to the last 50 years, but their U(ti) SF is significant, therefore, the effect of droughts Climate and excessive perceptions for agriculture, drinking and industry in the last decade, which has greatly diminished as a result of river flows.

    Conclusion

    Assessing the results of the T- Student and Mann-Whitney tests in this study showed that from 1968 to 2018, rainfall and annual flow volumes of all catchment areas across the country had a relatively slow downward trend. Also, according to the results of the Man-Kendall test in the catchments of Dez-Karoun, Karkheh, West border, Lake Uremia, Central plateau, Hamoun and Serakhs, the trend of long-term variability of atmospheric precipitation (except for the Gherahso-Gorgan basin) has been very low. Since From 1998 to 2018 annual precipitation values have declined over the past half century, but U(ti)R are meaningful and, therefore, can be attributed to the certainty of the trend of rainfall variability to the phenomenon of climate change. What is certain is that the process of variation of surface flow volume in comparison with annual rainfall has very large fluctuations and has a decreasing intensity several times. It seems that rainfall reduction is the cause of the rivers discharge volume, but other factors such as Excessive harvesting in the upper reaches of the catchment areas has always been effective for the use of various sectors, so according to U(ti) SF, they can be attributed to the climatic phenomenon as the definitive causes, therefore, according to the results of my Kendall test The effect of climate change on the reduction of annual yield and the volume of surface Flow of rivers are skeptical. Keywords: Climate Change, Precipitation, Man-Kendall, Renewable Water Resources.

    Keywords: climate change, Precipitation, Man-Kendall, Renewable Water Resources
  • Hossein Asakereh *, Leila Ahadi Pages 375-394
    Introduction

    Neglecting the environment in recent years has caused many environmental problems. The Extensive development of cities and urbanization, the growth of industrial sector, especially in the vicinity of large cities and combining them with a range of natural and climatic factors, increase the air pollution and change the urban environments, and some of the globalized ones, so the environment gets out of balance and seriously damage and it has raised human concerns for the future. The most important problems of the last two decades are greenhouse gas emissions and global warming.Air pollution is one of the major environmental and economic problems that have emerged around the world and this issue, especially in large industrial cities, is a more acute problem. It can be said that air pollution has started since the invention of fire. When Industrialization reached the forefront of development, urban climate and air quality changed dramatically, leading to changes in the hydrological cycle, agriculture, irregular rainfall, as well as increasing drought and floods.The weather conditions on each day are affected by the synoptic conditions prevailing in each region on that day. In other words, it is due to the arrangement of atmospheric systems in relation to each other and the dynamic and thermodynamic properties that govern them. Therefore, the synoptic pattern is sometimes such that the conditions of stability and calm prevail in the atmosphere, and as a result, due to the density of pollutants in the lower layers and lack of atmospheric currents or their weak intensity, the intensity of pollution and increased. Synopticity is such that it makes the atmosphere unstable and due to the intensification of vertical and horizontal currents, contaminants are spread inside the atmosphere and its concentration decreases.As mentioned above , Air pollution is a significant issue, especially in metropolitan areas. The atmospheric conditions and the air types of the cities are the factors that aggravate this problem. Tabriz metropolis faces severe air pollution. The main objective of this study is to investigate the relation between atmospheric conditions and the air type of the Tabriz city in the intensification of air pollutants.

    Materials and methods

    Three types of data are used in this study, including: a) the mean of the hourly data of atmospheric pollutants, b) the mean of the daily weather data to extract air types, and c) atmospheric data to study atmospheric patterns of air types.The weather type of Tabriz city was clustered based on the Euclidean distance and with the integration method "Ward". Accordingly, for the day's selection, the representative will be selected the day most closely resembling the group's maximum number of days. Then, using daily atmospheric data (including sunshine hours, dew point temperature, minimum visibility, average cloudy, average vapor pressure, average wind speed, station pressure, sea level pressure, rainfall, average temperature, average minimum temperature, average maximum Temperature, mean relative humidity, mean relative humidity and average maximum relative humidity) at Tabriz station, the relationship between air pollution and pollution in Tabriz city was investigated.

    Results and discussion

    Trial and error, applying the mid-group and outsourced type tests, it was revealed that the three weather types were prevalent in Tabriz during the study period. Representative days were extracted from 3 weather types.Regarding PM10 pollutants and air types, it was found that days with a hazardous state of concern for PM10 have occurred in type 2. For this reason, three days with low, moderate and dangerous pollution were extracted from PM10 in type 2. The days of the representative of the three brigades were as follows:weather types 1: 29/3/2004, weather types 2: 3/4/2004, 15/4/2005 (For PM10 with low pollution), 28/11/2005 (For PM10 with moderate pollution) and 6/5/2009 ( In terms of PM10 with high contamination (and type 3: 14/4/2004)By investigating atmospheric variables and atmospheric pollutants, it was found that the amount of air pollution is more related to wind speed and direction. The winds are low in winter, but there are plenty of swings in this season from the southwest and west. Most of the major industries in the city of Tabriz are in the west of the city, which winds the west of suspended particles into the city, and the Ainal and Zinalal mountains in the northeast of the city function as a barrier against the wind stream, and the suspended. wind carried particles to the The city. In the winter, there is a reversal that intensifies pollution and concentration in the city and reduces its transmission to other parts.

    Conclusion

    The results of the survey of air types associated with infected days show the dominant wind direction in these days is from southwest, northeast with a relatively low speed which is the result of the deployment of two high-pressure centers of Europe and Siberia in the northwest and northeast of Iran and one low-pressure center on the Caspian Sea. As a result, the movement of air from high-pressure areas to the low-pressure zone in the clockwise direction has led to the development of south-west flows. On the days when the PM10 pollutant has reached its highest level, in the 1000-HP level a low-pressure center and in the 500-HP orbital flow is dominant in the study area. The wind of sea-level and the 500-HP were from southwest and west. Since the industries and factories of Tabriz city are located in the west side of the city, the mentioned low-pressure in connection with adjacent systems leads particles and industrial pollution to the center of the city.Most of the major industries of the city such as thermal power plant, petrochemical complex, refinery etc. are located in the west of the city.Tabriz is surrounded by rough terrain and is located in a valley where pollutants cannot spread easily and sometimes condense on top of the area. Winds from the west bring suspended particles to the city, and the Aynal and Zinal Mountains in the northeast of the city serve as a barrier against wind currents and suspended particles carried by the wind over the city.The provisional nature of suspended particulate contamination confirms the existence of a temporary diffusion factor, namely the wind factor, so there is a direct relationship between the increase in air and wind particulate matter from the southwest of Tabriz.

    Keywords: Air pollution, atmospheric pollutants, Tabriz, Cluster Analysis, AQI Index
  • Adel Nabizadehbalkhkanloo *, Parviz Zeaieanfirouzabadi, ALI Khedmatzadeh Pages 395-408
    Introduction

    In recent years, lower than the water level of Lake Urmia, the study of changes in temperature, humidity and drought stress thresholds in the area of inevitability is inevitable.Drought is a difficult weather event and a "crawl" disaster. From the agricultural perspective, drought has occurred when the soil moisture is less than the actual needs of the product and leads to damage in the product. For drought analysis, the existence of an indicator for the accurate and reliable determination of wet and dry periods is very necessary.

    Materials and methods

    In this descriptive-analytical and purpose-oriented study. The MODIS sensor data based on the Terra satellite was used. In these images, 8-day composite products with a resolution of 1 km and 8-day surface reflectance with a resolution of 250 m at time interval (2005 to 2008) were used for five consecutive months from June to October. Linear regression was used to derive the results. Also in this study 5.1ENVI, 10.5ARC GIS was used for analysis.The purpose of this study is to use MODIS sensor to evaluate the spatial relationship between NDVI-Ts and NDVI-ΔT for extracting real-time agricultural droughts in the Simineh River watershed from the catchment area of Lake Urmia, The VTCI Index (Vegetable Temperature Index) and WDI (Water Deficiency Indicator), which are capable of identifying regional drought stress. The second component of the material used in this research are:1. MODIS/Terra Land Surface Temperature/Emissivity8-Day L3Global 1km SIN Grid V004MODIS/Terra Surface Reflectance 8-Day L3 Global 250m SIN Grid V004 .2MODIS products produce surface temperature and reflectivity, their reflection and pixel magnitude. The VTCI index (duration of drought) is based on a simplified NDVI-TS triangular space in which the "cold edge" (non-stressed conditions) is considered as a line that has the lowest temperature in the NDVI axis (X-axis) and the "hot edge" (non-availability of water) is interpreted as a negative link with the NDVI. The WDI index (drought severity) can be further labeled as the wet line or ETR with a maximum of ΔLST NDVI min and the dry line or ETR is at least equal to Δ LST NDVI max.

    Results and discussion

    The vegetation temperature index (VTCI) is calculated based on the relationship between the NDVI-TS triangular space. The hot and cold edge pixels are derived as linear regression equations for calculating VTCI using ENVI software in mathematical data, in which ground temperature (LST) and NDVI index images are used as input parameters for the VTCI equations Is In all these years, it is observed that the gradient for the hot edge is negative, while for the cold edge it is slightly negative or no appreciable change. The gradient shows that when the NDVI value increases for any time interval, the maximum temperature decreases. The gradient on the cold edge indicates that when the NDVI value increases.The Water Deficit Index (WDI) is calculated on the basis of the ΔTs-NDVI spatial relationship, the wet line pixels and the dry line are determined by the linear regression equation, and the extracted equations were used to calculate WDI. In calculating this index, the difference between the surface Temperature (TS) extracted from the satellite imagery and the temperature of the weather stations (Ta) as a parameter (ΔT), and NDVI images are used as another input parameter for the WDI equations. Therefore, the wet and dry line is obtained from the NDVI-ΔTS triangular barrier. The slope obtained from the NDVI-ΔTS spatial relationship is negative for the dry line, while the gradient obtained for the wet line is positive and in the rest of the years there was no significant change. The negative slope shows that ΔT Max decreases with increasing NDVI index and positive slope shows that ΔT Min increases with increasing NDVI index.The study period shows that the 2005-2006 period in the study area has a higher VTCI content than the years 2007-2008, which means less stress. The low VTCI has a tendency to stress and its high value indicates favorable conditions. The low VTCI value is less than its higher value in the obtained maps, which expresses the relative favorable condition of drought stress throughout the studied region. Generally, the lower Simineh, upstream of Bookan County, and to some extent the Hajiabad Plain, Miandoab, are areas that show less moisture conditions during 2005-2007. These areas, namely the Simineh River (between Miandoab and Bookan), show lower VTCI than the Simineh Rivers (between Mahabad and Bookan) and Simineh River higher (between Bookan and Saggez). The more northerly regions with high VTCI levels are less humid and have good conditions. VTCI is higher in these areas due to irrigation options that vegetation does not tend to moisture.The WDI spatial pattern has also been studied in the Simineh River watershed from the main catchment area of Urmia Lake for the July 153 day in 2005-2008. The lower WDI represents the optimal conditions, while the higher VTCI represents the favorable conditions in that area, and the range of this index is the exact opposite of the VTCI index. According to the maps drawn from the WDI index, it can be seen that during the period from 2006 to 2008, the WDI spatial pattern is similar to the VTCI index. Although the spatial patterns of both indicators are similar, the WDI index offers a distinct class of this situation. In the entire catchment area of the Simineh River, the water stresses were severe in 2005, but gradually increased from 2006 to 2008. In the middle and upper part of the upper part, the WDI is high, indicating that all areas between Bookan and Mahabad are exposed to moisture stress. The northern Bookan districts of the northwest and the Haji-Abad area of Miandoab show relatively good conditions, and in 2008, all mid-zone regions such as the eastern, western and northern Akhtachi show a higher WDI.The overall analysis shows that the duration and severity of stress are similar according to the VTCI index as well as the WDI index from favorable conditions to stress conditions, and shows that in general, in 2005-2007, the temperature and humidity stresses in the study area gradually, the tensions peaked in 2008.

    Keywords: Simineh River Basin, Agricultural drought, MODIS, VTCI, WDI
  • Aliakbar Garmsiri Mahvar, Ghasem Azizi * Pages 409-428
    Introduction

    Subtropical high pressure systems are among the atmospheric large scale centers of action in the northern hemisphere in the east of the oceans. The high pressure in the Atlantic called "Azores" or "Bermuda" and in the Pacific called "Hawaii". The clockwise flow around these systems in the south comes from easterly trade winds and in the north from the westerly belt of the mid-latitudes. Both of these currents are influential in the formation and development of this systems. Surface pressure and clockwise flow in these systems reach the maximum in the warm season, especially in July. While at this time there are thermal low pressures on most continental. For the first time Bergeron (1930) in context of air mass and frontal development argue that a surface high pressure belt exist in the subtropics around the earth. This belt has generally been attributed to the descent in the pole-ward branch of the meridionally overturning Hadley Cell. Bjerknes (1935) argued for such a belt structure from “stability considerations,” and discussed the organization of the subtropical anticyclones, including continentally anchored cols. Rodwell and Hoskins (2001) emphasize that the zonal-mean of the Hadley Cell in the summer of the northern hemisphere is much weaker than in the summer of the Southern Hemisphere, and that the circulation is not strong enough to produce the observed summer peaks of the intensity of the subtropical high pressure. Therefore, the classical Theory of the Hadley Cell Theory not be able to describe the existence of the maximum sea level pressure at the sub-tropic of the northern hemisphere. Study of this systems that affecting the oceans and continents in the hot season requires analyzing many phenomena in the atmosphere. These include the Hadley meridional circulation, warming in the atmosphere, monsoon events on the continents, and latent heat released in the upper levels of the atmosphere and etc. The structure and mechanism of each of these phenomena are also complex. Therefore, it is not possible to address many of the above in the context of research at this level. Internal investigations do not seem to have much tangible and close relevance to subtropical high-pressure systems. These studies are based on the geopotential pattern in different levels, and most of the studies focus on seasonal variations, displacement, and the relationship of this pattern to other atmospheric phenomena. While a fundamental question arises in the mind, "how much this quantity depends on the mechanism of subtropical high pressure systems and whether the formation of geopotential patterns can be related to the subtropical high pressure systems or their origin?" This study attempts to provide a convincing answer and analysis based on the findings and foundations.

    Material and method

    In this research, sea level pressure, wind vector, omega, geopotential height and horizontal divergence are used. Initially, the monthly mean of sea level pressure and wind vector averages at 6 levels (700, 750, 775, 800, 825, 850 hPa) in the North Atlantic and North Pacific were analyzed. Sea level pressure in has been used as a measure of the intensity, development, and displacement of subtropical high pressure systems. The mean wind in the above 6 levels is also used as a current in these systems. Due to the high resolution of the data, the wind cannot be represented in vector form and this quantity is presented as stream lines. Monthly intensities and displacements of high-pressure centers on the North Atlantic and Pacific are investigated based on the maximum monthly mean sea level pressure. In the second part, in order to identify the extent and subsidence of these systems, the pattern of the vertical cross section of the meridional wind and omega is investigated at the position of these systems. Finally, the vertical cross-section of geopotential height and horizontal velocity divergence in the position of these systems in July is analyzed. To better understand and analyze these systems, the study was conducted in hot (April to September) and cold (October to March) periods. The data were extracted from the European Center for Medium-Range Forecasts (ECMWF) and the ERA5 version with a horizontal resolution of 0.25 * 0.25 degrees. This data is a reanalysis of stationary data and outputs of numerical models. Monthly averages of quantities used over a 40 year period from 1979 to 2018. result and Discussion In July, at the sea level the center of the Anticyclone corresponds to the maximum of pressure and at higher levels corresponds to the maximum of Geopotential height. Therefore, the counter clockwise flow and sea level pressure are the two main factors in the formation of height cells in the lower levels. Another point is that the maximum sea level pressure and the height of the geopotential at the lower levels do not correspond to the maximum divergence and subsidence of the air, respectively. Therefore, on the one hand, the subsidence of air flow cannot be considered as the main factor for the formation of maximum sea surface pressure, and on the other hand, the idea of the effect of adiabatic heating due to subsidence in the formation of height cells is negated. At this time, the maximum height of the Geopotential at the upper levels occurs on the western flank of Anticyclone. The ascent of hot air and the latent heat released on the western flank are the main factors in formation the maximum height or ridge in this area. The extent status of Anticyclone in July exhibits prominent patterns of counter clockwise flow, sea level pressure, geopolitical height, ascent and descent of air, divergence, warm and cold advection, and other atmospheric quantities. These patterns show the effects of these systems on the wide thickness of the atmosphere. 

    conclusion: 

    In this study, an attempt is made to display a more comprehensive analysis of the structure of Subtropical High Pressure Systems (Azores and Hawaii) using atmospheric data, which will certainly be effective in our knowledge and analysis of Anticyclone systems on continents. This study includes variability and vertical cross-section of flow, vertical velocity, divergence and geopotential height in these systems. It seems necessary to distinguish between Azores high-pressure and upper level atmospheric high systems with anticyclonic rotation.

    Keywords: Azores High pressure, Anticyclone, Subtropical high pressures, Hawaiian high pressure
  • Nooshin Ahmadibaseri, ALIAKBAR SABZIPARVAR *, Mehraneh Khodamoradpour, Juan Luis Guerrero Rascado, Lucas Alados Arboledas Pages 429-443

    Surface solar radiation (SSR) is a fundamental key variable in climatological and meteorological studies. The most accurate way to obtain SSR at the surface is to measure solar irradiances using radiometers such as pyranometer. However, ground measurements are limited due to the high cost of the calibration and the regular maintenance of the equipment. To eliminate this problem, many methods have been developed to estimate solar radiation received by the Earth's surface: including, empirical models, radiative transfer models (RTM), semi-empirical models, and models based on satellite products. One of the most popular and easily accessed methods for estimating SSR is satellite-based methods, having advantages of high temporal and spatial resolution, low cost and free access can be a good alternative source for areas without stations and areas with heterogeneous distribution of stations. This work is aimed to evaluate and validate SSR derived from three satellite-based products (CERES, CLARA and SARAH) against ground measurements over Iran daily.

    Materials and methods

    Ground measured data: In this study, measured SSR was extracted from 24 radiometric stations of Iran from 2012 to 2015. The SSR ground measurements are more susceptible to error than other meteorological parameters. Therefore, quality control was applied in order to remove likely errors and outliers from the measured data. In this study, Moradi's proposed method was used for data quality control (Moradi, 2009). The studied areas were classified based on Digital Elevation Model (DEM) and UNESCO climate classification approach into three zones of arid, semi-arid and coastal climates. Satellite-based data: The satellite-based SSR outputs including CERES, CLARA, and SARAH were extracted for the period of 2012 to 2015. The satellite scientific instrument of CERES (Cloud and the Earth's Radiant Energy System) is a component of NASA’s Earth Observation System (EOS) onboard the Terra and Aqua platforms. The CERES datasets provide global coverage available from 2000 to present with a spatial resolution of 1 degree and temporal resolution of daily and monthly (Carmona et al. 2017). The Climate Monitoring Satellite Application Facility (CM SAF) provides high-quality records for climate applications from satellites. The CM SAF CLARA products are based on observations of the AVHRR instruments onboard the NOAA and METOP polar-orbit satellites. The CLARA datasets prepare global coverage with a spatial resolution of 0.25 degrees on a regular latitude-longitude grid and daily and monthly temporal resolution available from 1982 to 2015. The CM SAF SARAH products are based on observations from the MVIRI and SEVIRI (Spinning Enhanced Visible and InfraRed Imager) instruments onboard the Meteosat First- and Second-Generation satellites. The SARAH datasets supply regional coverage (Europe, Africa, the Atlantic and parts of South America) with a spatial resolution of 0.05 degrees on a regular latitude-longitude grid and instantaneous, daily and monthly temporal resolution available from 1983 to 2017 (Riihelä et al. 2015).

    Methods

    Since the satellite-based products studied are generally distributed in NetCDF format, the nearest neighborhood interpolation method was used to match these data with measured data. Then, satellite-based datasets were generated for station points using CDO software. In this study, satellite-based datasets were compared against measured SSR datasets by four validation metrics. The metrics used are determination coefficient (R2), the mean bias deviation (MBD), relative mean absolute deviation (RMABD) and root mean squared error (RMSE).

    Results and discussion

    Evaluation of the performance of CERES, CLARA, and SARAH products in estimating daily SSR in Iran showed that despite the proper performance of all three satellite-based products in this study, SARAH with R2= 0.93 and MBD= -0.1 W.m-2 has the highest agreement with measured SSR compared to other two products. This result is consistent with the study by Journée and Bertrand (2010), Urraca et al. (2017), Alexandri et al. (2017) and Wang et al. (2018). Also, evaluation of the monthly and seasonally variations of daily SSR of three satellite products against the measured daily SSR showed that the studied satellite products are more capable of estimating SSR under clear sky conditions (warm seasons) than cloudy conditions (cold seasons). Spatial variations of daily SSR showed that the satellite products in the arid and semi-arid climate regions had the best performance, respectively, compared to the coastal regions. In this aspect, SARAH provided the best performance in all three study areas. According to the results, the highest agreement between ground measured SSR and SARAH was observed in the dry climate (R2= 0.94) and the lowest agreement between ground measured SSR and CERES was observed in the coastal region (R2= 0.83). Also, the largest overestimation occurred by CERES in the coastal region with MBD of 21.3 W.m-2 and the smallest underestimation by SARAH in the arid climate region with MBD of -0.1 W.m-2. Also, the smallest RMSE obtained in the arid climate region by SARAH with 20 W.m-2 and largest in the coastal region by CERES with 37.3 W.m-2. These findings are consistent with the results obtained by Thomas et al. (2016), Urraca et al. (2017) and Urraca et al. (2018). Their results showed that in the coastal regions with high humidity, the errors of satellite- based SSR estimates are very high. Seasonal variations of RMABD showed that the maximum and minimum RMABD in arid and semi-arid climate regions occurred in winter and spring, respectively. These results are consistent with the results shown by Sanchez-Lorenzo et al. (2013) and Wang et al. (2018) that indicate the lowest ability of studied satellite products in cloudy conditions (winter) than in clear sky conditions (summer) to estimate SSR. In coastal regions, the minimum and maximum RMABD were found in spring and summer, respectively. As shown in this study by Thomas et al. (2016) and Urraca et al. (2017), humidity and water vapor in the atmosphere are some of the causes of high error in satellite products. Since the coastal areas studied in this study (Bandar Abbas and Gorgan stations) have warm and humid summers, therefore, the maximum RMABD occurred in these regions in summer and the minimum RMABD in spring with lower humidity and cloudiness than other seasons.

    Conclusion

    The results showed that SARAH with the highest spatial resolution compared to CLARA and CERES had the best performance in generating daily SSR in Iran. Also, the high error in cold seasons indicates the high impact of cloudiness in reducing the accuracy of studied satellite products in Iran. Investigation of spatial variations of daily measured SSR and studied satellite products also showed that the satellite products have the highest performance in arid and semi-arid climate regions but the lowest for the coastal regions. Most regions of Iran located in arid and semi-arid climate region and the growing season of these zones are in accordance with the warm season. Therefore, due to the acceptable performance of satellite products to estimate SSR in arid and semi-arid climate regions and in warm seasons, accordingly, SSR outputs of satellite products can be used in agricultural studies. Also, given the free availability and high spatial and temporal resolution of the satellite products under investigation, the SSR output of these products can be a good alternative for areas where there is no access to the ground based measured SSR datasets.

    Keywords: Surface radiation products, CERES, CLARA, SARAH, Monthly, seasonal comparison
  • Majid Ahmadi Molaverdi, Iraj Jabbari *, Amanollah Fathnia Pages 445-465
    Introduction

    Dust storms are atmospheric events caused by the removal of fine particles from the surface of the earth. Not only natural but also human factors are involved in the emergence of dust. As human activities change the stability of geomorphic surfaces, areas susceptible to wind erosion may increase and the release of waste materials will increase abruptly. Dust can have devastating effects on the environment and human activities, which has many consequences for human society. Researches show that in Iran, the phenomenon of dust, especially in western provinces such as Kermanshah, is so widespread that researchers regard it as the most important environmental problem. The dust that affects the western and southwestern parts of the country is mostly trans-local and originates from neighboring countries. But in recent years, with increasing environmental changes in the country's western provinces, attention has been drawn to the potential production of domestic dust sources. A new pathway to environmental management and control measures will be opened if the dust sources are identified. Therefore, in this study, in addition to identifying the origin of dust and its prone areas in Kermanshah and Ilam provinces, it is attempted to study the characteristics of these areas in terms of land cover and geomorphology. Attempts have been made to identify the factors that have caused and exacerbated this phenomenon in recent years to prevent and reduce the occurrence of this phenomenon given the environmental conditions and facilities available.

    Methods and Materials:

    In this study, meteorological data were used to determine the occurrence of dusty days and satellite images were utilized to identify dust sources. Days were considered as days of dust occurrence where at least one station had recorded meteorological codes related to the dust phenomenon and had a horizontal visibility of less than 1000 meters. Out of 210 days of dust, 21 images (from 2008 to 2008) were selected to identify the origin of dust and the rest were excluded for various reasons. In order to detect dust, first, MODIS images were geometrically corrected in the ENVI 5.3 software. Then, using software Erdas Imagine 9.1 and TDI Index the dust was detected. In this study, in addition to satellite imagery, Hybrid Single-Particle Lagrangian Integrated Trajectory )HYSPLIT( was also used to identify the direction of wind movement and the origin of dust. After making radiometric and atmospheric corrections, four land use classes were extracted (forest, rangeland, agriculture, and built-up land) in 2000 and 2015 with Maximum Likelihood algorithm in Software ENVI 5.3.Finally, by comparing these two maps, land use change map was prepared and seven land use changes classes (forest to rangeland, forest to agriculture, rangeland to agriculture, forests to built-up land, rangeland to built-up land and agriculture to built-up) land were extracted in total. To prepare the geomorphological map, the geomorphic classification scheme of Boulard et al. (2011) was used. For this purpose a combination of remote sensing and Landsat imagery data, 1: 100,000 geological maps of Iranian oil operating companies, the Iranian geological survey and mines exploration resources and land capability map (The soil texture profile of the area was extracted from this map) were used. After determining the geomorphic unit boundaries of each polygon, it was assigned to one of the 17 geomorphic classes classified by Boulard et al. (2011). Finally, the origin of the identified dust points was overlaid on these maps and their distribution and frequency were determined for each geomorphic class and land use change.

    Results and discussion

    This study identified dust sources in Kermanshah and Ilam provinces and examined the role of land use change and geomorphology with regard to dust production. A total of 396 dust sources were identified during the study period (years 2008-2013). On each image, the number of sources identified varied from 2 to 15 points. The dispersion of the dust sources detected on 21 satellite images shows that Kermanshah and Ilam provinces do not produce the same amount of dust, but most of the dust sources originate from several important areas in the west of these provinces including areas around Ezgeleh, Qasr-e Shirin, Naftshahr, Sumar, Mehran, Dehloran and Abu Ghovair village. Evaluation of the characteristics of dust sources shows that areas affected by land use change have the most potential for dust generation and among different classes of land use change, land use change from rangeland to agriculture has had the highest effect in dust production. In addition, Of the 17 geomorphic classes identified by Boulard et al. (2009), there are 6 classes in Kermanshah and Ilam province. Geomorphologically, alluvial systems are the most important producers of dust and among the different types of geomorphology, the class 2C has a more significant role in the production of dust. The dusts identified on the MODIS images show that a large number of these are originated from piedmonts and alluvial fans near the Zagros Mountains (class 2C). In addition to piedmonts and alluvial fans, alluvial plains and floodplains (3c, 3d) are other important geomorphological species in the region that have contributed significantly to the production of dust. In the seven important dust producing regions identified in Kermanshah and Ilam, different land use and geomorphology classes do not produce the same dust, so the most appropriate method for combating wind erosion should be selected in each region.

    Conclusion

    Evaluation of the severity of wind erosion in the dust producing areas of Kermanshah and Ilam indicates that anti-erosion methods should be prioritized in piedmonts, alluvial fans, alluvial plains and floodplains. Some measures should be taken to prevent wind erosion at the source and others should be outside the source and upstream (watershed measures).In natural ecosystems and rangelands, it is best to avoid change of use, over-grazing, etc.to prevent wind erosion. In agriculture controlling measures that make the soil less vulnerable to wind, such as crop residues, gravel mulch should be taken. Pebbles or gravels should be used to restore natural vegetation in grasslands that have become arable land.

    Keywords: Dust Management, Land Use Change, geomorphology, MODIS images, Kermanshah, Ilam
  • Mohammad Azadi Mubaraky, Mahuod Ahmadi * Pages 467-480

    Particulate matter (PM) or aerosols is a generic term used for a mixture of solid particles and liquid droplets in the atmosphere. Monitoring of natural (dust and volcanic ash) and anthropogenic particles (soot from biomass burning and industrial pollution) has attracted much attention in recent years. These particles can affect cloud properties, Earth's radiation budget, overall atmospheric circulation patterns, surface temperature, and precipitation. The emission of particulate matter and its associated stimuli comes from sources such as energy consumption and biomass burning in urban environments, and these two factors are commonly known as major contributors to PM2.5 concentrations in the atmosphere. However, surface PM2.5 concentrations are related to many factors such as meteorological conditions (eg temperature, wind speed, and relative humidity), land use type, population, and road networks, and so on. In recent years, many studies have been conducted using Aerosol Optical Depth (AOD) satellite measurements, AOD is a very important parameter for predicting Particulate matter (PM) at the Earth's surface in unmeasured locations or periods. AOD determines the amount of light absorbed or scattered by particulate matter. It is, therefore, an important parameter for predicting changes in PM although it may have deficiencies in this regard;The purpose of this study was to estimate the particulate matter in the atmosphere of Tabriz city using a high spatial resolution weighted regression model (0.1-degree arc, 10 km apart). For estimating PM2.5 in Tabriz during the period 1998 to 2016 will be used combined data from SeaWiFS, MISR, and MODIS data.
    Research

    Methodology

    As mentioned earlier, meteorological conditions can substantially affect the relation of AOD-PM2.5. Aerosol concentration variability can change particle extinction properties and thus affect visibility. Visibility is an indicator of urban air quality, and particular matter is adversely associated with visibility impairment.Geographically weighted regression (GWR) is a technique mainly intended to indicate where nonstationary is taking place on the map and that is where locally weighted regression coefficients move away from their global values. GWR is also a local form of linear regression used to model spatially varying relationships. Hourly data of particulate matter less than 2.5 µm (PM2.5) in air pollutants were obtained from Tabriz air quality control stations for 2016-2013. Aerosol Optical Depth (AOD) Data from Three Moderate Resolution Imaging Spectroradiometer (MODIS) of Terra and Aqua Satellites with Two Dark Target (DT) and Deep Blue (DB) Algorithms, Multi-angle Imaging SpectroRadiometer (MISR) and the GeoEye's OrbView-2 (AKA SeaStar) SeaWifs satellite sensor were used. The data were downloaded from the Ladsweb database of The National Aeronautics and Space Administration. Finally, non-parametric Mann-Kendall and Sens' slope estimator methods were used to investigate the trend and trend slope of the PM2.5 in Tabriz.

    Results and discussion

    Statistical indices of R2 and RMSE for PM2.5 showed that satellite data have high accuracy in estimating PM2.5. The R2 of Long-term time series data was 0.878 and RMSE was 1.330. The annual mean distribution of PM2.5 in Tabriz showed that PM2.5 was higher in western parts of the city than in other areas. Therefore, this area was identified as a polluted area in Tabriz. The PM2.5 in the city of Tabriz from 11.29 to 16.86 µ/m3. The southern and northern regions of the city showed the smallest PM2.5. The western and northwestern regions of the city, especially Tabriz's 4th, 6th and 7th districts, are the main areas of heavy industry, high density of roads and accelerated urban sprawl. This geographic environment has a significant impact on the emissions of primary greenhouse gases and secondary mineral pollutants. Unfavorable weather conditions on the planetary boundary layer (PBL), continuous inversion, and poor wind speed in winter can cause more pollutants to accumulate in a shallow layer. The annual mean long-term PM2.5 of Tabriz city was calculated to be 14.04 µ/m3. During the period of the first study period (1998-2002), PM2.5 was lower than the long average but from the second period onwards the particles with a steep slope in Tabriz have increased as in the third period (2012- 2008) and the fourth period (2016-2013) of particulate matter exceeded the long-term average value.The highest Z-score of the Man-Kendall test was 2.69 in the western and northern parts of the city. Zones 1 and 2 also showed the lowest Z score of 1.75. The trend slope, which shows an increase in PM2.5 per head per year in Tabriz. According to the results, PM2.5 in Tabriz Variability between 0.250 to 0.25 µ/m3 (year-1). According to the results of Mann-Kendall test, Sense test also showed maximum gradient with 0.225 µ/m3 in western parts of Tabriz (4, 6 and 7 urban areas). The Z-score of the Man-Kendall test was 2.69 in the western and northern parts of the city. Zones 1 and 2 also showed the lowest Z score of 1.75. The trend slope, which shows an increase in PM2.5 per head per year in Tabriz.

    Conclusion

    In this study, Seawifs, MISR and MODIS satellite data were used to estimate PM2.5 using Geographic Weighted Regression (GWR). The results showed that the western and northwestern regions, along with significant parts of central Tabriz, have high PM2.5 values. In Tabriz, the lack of proper ventilation of wind speeds caused by urban buildings, along with the meteorological conditions of the local area, can be attributed to the high accumulation of particles. The least polluted areas were identified in the south and southeast of Tabriz. These areas are highly favorable for atmospheric dispersal due to low greenhouse gas emissions and meteorological conditions. The northern areas of Tabriz have a high PM2.5 due to the possible existence of farmland. However, economic and social factors such as industry, traffic, construction and burning of fossil fuels are direct sources of air pollution in Tabriz. But what is known is that socio-economic factors are less effective than natural factors in the city. Climatic conditions usually have a direct impact on PM2.5 in various aspects of wind-induced diffusion, precipitation of particulate matter, accumulation of particles in the air, and formation of secondary particles.

    Keywords: PM2.5, Geographic Weighted Regression (GWR), Air quality control, Tabriz
  • Asghar Molaei, Hassan Lashkari * Pages 481-498
    Introduction

    Among climate variables, wind has a skewing role due to its high spatio-temporal variability and its role in other parameters such as air temperature. It is important to study wind changes in different ways so as wind speed decreases its energy and consequently increases urban pollution. Reducing the wind speed also reduces heat transfer, viscosity between the earth's surface and the atmosphere, and ultimately increases the temperature. Decreasing wind speeds at night, especially in winter nights, cause the Earth to radiate inversion. Increasing wind speeds will also result in high winds, tornadoes and damage to affected areas. Also, wind speed is one of the important components in combinatorial equations to estimate evapotranspiration and any trends in wind speed will also affect the water requirement of plants.As discussed, wind is a very important climatic parameter, but its study in particular is changing its course with limitations such as inaccessibility of homogeneous time series and long term data with inadequate stations. Station data, on the other hand, can also be affected by discontinuities associated with changes in measuring equipment, station location, or different measurement methods. To overcome these limitations, the re-analyzed global meteorological dataset, available for a long period, is useful for meteorological studies. In recent years, these databases have also been used for various wind energy applications.The purpose of this study was to evaluate wind speed changes and trends in central Iran and since most of the area is arid and insufficient stations, ECMWF database data were used. The results of this study can be useful for studies on climate change, agriculture and renewable energies.
    Research

    Methodology

    The study area is Central Iran. Central Iran is said to be bounded on the north by the Alborz Mountains, on the west and south by the Zagros Mountains, and on the east by the dispersed Khorasan Mountains. Much of central Iran has warm and dry climates that are milder and humid in the highlands. In this study, four provinces of central Iran were selected and evaluated for wind changes.Two groups of data were used in this study. 1- Wind speed data from Synoptic stations and 2- Wind speed data from ECMWF ERA-Interim version with spatial resolution of 0.75 × 0.75 °. Kolmogorov-Smirnov (K – S) test confirmed the normality of the data and the missing data were reconstructed using linear interpolation method. Synoptic station data were also used to validate the ERA-Interim ECMWF database data. Coefficient of determination (R2), Mean bias error (MBE) and root-mean-square error (RMSE) of open data analysis of ECMWF database ERA-Interim were used for wind speed trend in central Iran with nonparametric Mann-Kendall test. Was evaluated.

    Results and discussion

    Minimum wind clock speeds are only less than 2 meters in November (1.98) and December (1.96). In other months this fluctuates between 2.01 and 2.59 meters. The maximum wind speeds were also between 3.43 and 5.90 meters, respectively, from November to July, respectively. During the warmer months of June (Jun, July and August) the maximum wind speed is more than 5 meters. The average wind speed is also presented in this table, based on the results of the long-term minimum wind speed in central Iran with a mean of 2.83 meters in January and its maximum with a value of 3.95 meters in July. On this basis, it can be said that during the cold period of the year in central Iran, the wind speed is slower, as the hot months of the year ahead, the wind speed will increase. The average annual wind speed was 3.19 meters. Among the seasons and months studied, winter showed the highest intensity of the trend of increasing wind speed (Z-score of 4.916 Mann-Kendall test), which is significant at 99% level. The focus of the maximum wind speed increase trend is in Semnan province, and as we move from January to March, the intensity of the trend increases. The highest percentage of incremental trend zones is in February, with 92.20% of central Iran showing an increasing trend of wind speed this month. June with 80.52% of the upward trend zones after March accounted for most of the areas with upward wind speeds in the spring. In contrast to the upward trend zones that peaked in January but the maximum upward trend intensities in April reached the Mann-Kendall Z test score of 4.031, which was statistically significant at 99%.

    Conclusion

    The results showed that the ECMWF database is well suited for wind clock evaluation. The Shahroud, Yazd and Kerman stations showed maximum coefficient of determination (R2) and minimum error. Yazd and Kerman also showed less deviation from synoptic stations. Minimum wind speeds in November and December and maximum wind speeds were calculated in July and June. The mean wind speed was calculated based on the ECMWF results of 19.1 m / s. The average wind speed in central Iran is directly related to the air temperature and season. Generally, during the cold season of the year the wind speed from south to north and during the warm season from north to south of central Iran is increased due to the location of arid regions such as Dasht-e Kavir in the north and Dasht-e Lut in the south of the study area. The trend of the wind clock in central Iran has shown that the maximum intensity of the trend of increasing wind speed is in the winter of March (Mann-Kendall Z test score of 4.916) which is significant at 99% level. Also, the maximum decreasing trend with the Z-score of Man-Kendall test is -2.73 in December. The upward trend of wind speeds in more than 50 percent of central Iran in 10 months of the year, while only in October and February, is the decline observed in more than 50 percent of the study area. Since the most important factor in reducing or increasing wind speed is pressure gradient changes, wind speed variations can be a sign of climate change.

    Keywords: wind speed, ECMWF base, Mann-Kendall nonparametric test, Central Iran
  • Mansor Parvin * Pages 499-514
    Introduction

    Tectonics in geology is the causative factor of buildings and the relationship between the geometrical form of the building and the effective forces (Purkerman & Sedig; 2003, 38).Active tectonics also reflects the tectonic movements of the youngest period, the Quaternary, and in particular the Holocene and the present (Soleimani 1,1377 ). The Zagros Zone is tectonically active, and the Arabian-Orsian plate convergence in the northwest Zagros is a combination of shortening and strike-slip strike-slip movements (Blank et al., 2003,401). (2006) estimates shortening of the northwestern Zagros to a maximum of 5 mm per year, and Mirzaei (1997) estimates that more than 50% of the recorded earthquakes in Iran occur in the Zagros Zone and is the most seismic-prone area in Iran.Shabani (2004) has identified the Kandand fault as an earthquake source in Kermanshah province.The west of the Kerend Basin is in the folded Zagros Zone and the kerend seismic fault is located in this basin. Therefore, it seems that tectonics of the region is active and considering the location of the city of kerend West and many villages and human settlements in the basin, evaluation and estimation of its active tectonics is necessary. The purpose of this study was to evaluate and estimate the active tectonics of the Kerend West basin using drainage network analysis.

    Materials and Methods

    This research is based on descriptive-analytical, library, field, statistical, and geomorphic and morphometric indices. Research data include ten-meter DEM, 1: 100,000 geological map, and 1: 50,000 kerend topographic map, IRS satellite imagery, and Google Inheritance imagery.Also during field surveys and surveys of satellite and Google Earth imagery geomorphic evidence of active tectonics in the basin was identified.Then, using DEM of 10 m area, the area of the west of the Kerend basin and its drainage network were extracted and ranked using the Straler Waterway method.In this study, anomalies and morphometric indices were calculated, followed by morphometric indices of ga, R, Rb and Rbd and geomorphic indices of Af, T, Bs, SL and S (Table 1).The results of the geomorphic and morphometric indices are then compared with the geomorphic evidence and Based on the analysis of drainage network conditions and geological conditions, the active tectonic status in the west of Kandand basin is determined.

    Findings

    waterway of 1 rank have the highest rate of anomalies in the kerend West basin and the number of Hat hierarchical anomalies in this basin is 730 waterways.This illustrates the impact of tectonic activity on the drainage network of the kerend Basin.The values of a and ga indices also indicate anomalies in the drainage network and tectonic activity of the studied basin. The values of Rbd and R parameters also indicate the hierarchical anomalies and the impact of the drainage network on the kerend Basin from tectonic activity. The index value (Af) in the west kerend basin indicates active and tectonics uplifit on the left of the kerend River, That is the direction of the northwest-southeast river. The left fringe of the river is due to the uplift of the kerend anticline by the Zagros shortening and thekerend thrust movement in its southern flank.The index (T) of the west kerend basin reflects the topographic asymmetry of the basin.And indicates active tectonic interference and elevation of the left bank of the river.Indices (Bs) of the kerend Basin indicate that the uplift of the tectonically-induced mountain fronts is more active than the erosional processes and has stretched the form of the West kerend Basin.Indicator (S) of the kerend River indicates that the river is not in equilibrium due to active tectonics and is relatively straight.The index (SL) of the west of the kerend River reflects drastic changes in the river's longitudinal profile due to active tectonics.The large number of low-ranking waterways in the Kandrab West basin as a geomorphic evidence confirms the existence of anomalies in the drainage and tectonic network active in the basin and confirms the results of morphometric indices.The asymmetry of the watershed, the west of the river, and the drainage network and the longer length of the watercourses on the left of the river indicate the geomorphological evidence confirming the values of the AF and T indices.

    Result

    The anomalies of the drainage network of the Kerend West Basin were evaluated by morphometric indices and their results indicate the existence of hierarchical anomalies in the drainage network of the Kandrab Basin under the influence of active tectonics.Rank 1 channel anomalies are in addition to the hierarchical anomaly indices and its density in the branching indices.The results of geomorphic indices also indicate uplift of the left bank of the main river due to westward thrust movement of the mainland and this causes drifting of the basin and asymmetry of drainage network in the west coast of the east.Also formed and longitudinal profile and river bed anomalies indicate active tectonics of this basin.The results of geomorphic indices indicate active tectonics of the west of the Kerend basin.The results of morphometric indices, geomorphic indices and evidence of active tectonic geomorphology in the kerend West Basin confirm each other and indicate the active tectonics of the Kerend West Basin.Based on the results of this study, it can be concluded that tectonic activity in the west of the kerend basin is a general uplift of the basin as well as uplift of the left bank of the river due to the kerend active fault movement.This is consistent with the results of studies by Blank et al. (2003), Bachmanov (2003), and Hesami et al. (2006), who believe in the uplift of the northwestern Zagros. The tectonic activity of the kerend West basin as well as the entire northwest Zagros range can cause active tectonic hazards such as earthquakes. The anomalies of the drainage network of the Kerend West Basin were evaluated by morphometric indices and their results indicate the existence of hierarchical anomalies in the drainage network of the Kandrab Basin under the influence of active tectonics.Rank 1 channel anomalies are in addition to the hierarchical anomaly indices and its density in the branching indices.The results of geomorphic indices also indicate uplift of the left bank of the main river due to westward thrust movement of the mainland and this causes drifting of the basin and asymmetry of drainage network in the west coast of the east.Also formed and longitudinal profile and river bed anomalies indicate active tectonics of this basin.The results of geomorphic indices indicate active tectonics of the west of the Kerend basin.The results of morphometric indices, geomorphic indices and evidence of active tectonic geomorphology in the kerend West Basin confirm each other and indicate the active tectonics of the Kerend West Basin.Based on the results of this study, it can be concluded that tectonic activity in the west of the kerend basin is a general uplift of the basin as well as uplift of the left bank of the river due to the kerend active fault movement.This is consistent with the results of studies by Blank et al. (2003), Bachmanov (2003), and Hesami et al. (2006), who believe in the uplift of the northwestern Zagros. The tectonic activity of the kerend West basin as well as the entire northwest Zagros range can