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پژوهش های جغرافیای طبیعی - پیاپی 78 (زمستان 1390)

فصلنامه پژوهش های جغرافیای طبیعی
پیاپی 78 (زمستان 1390)

  • تاریخ انتشار: 1390/12/07
  • تعداد عناوین: 8
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  • مجتبی یمانی، هیوا علمی زاده صفحه 1
    مورفولوژی و رفتار شبکه‎ی زهکشی رودخانه ها به تغییرات حاصل از فعالیت های زمین ساختی، داده های رسوب‎شناسی و دینامیک جریان، بسیار حساس بوده و الگوی آنها تا حد زیادی از این عوامل تاثیر می‎پذیرد. این پژوهش، تاثیر این فعالیت‎‎ها را بر تغییرات مورفولوژی و بستر رودخانه‎ی کل، واقع در شمال‎غربی تنگه‎ی هرمز، مورد بررسی قرار داده است. مهم ترین شواهد آن، تغییر مسیرهای متعدد این رودخانه در دوره های زمانی مختلف است. همچنین مکان این تغییر مسیرها نیز، محدوده‎ی مشخصی را در سطح دلتا نشان می دهد و به‎نظر‎ می رسد بیشتر تحت تاثیر حرکات زمین‎ساختی و دینامیک جریان باشد. هدف از این پژوهش، بررسی شواهد موجود و ارزیابی تاثیر این عوامل در تغییرات بستر رود کل در محدوده‎ی دلتا است. برای دست‎یابی به این هدف و برای شناخت شیوه‎ی عملکرد و میزان اثرگذاری عوامل گفته‎شده در مورفولوژی و رفتار رودخانه‎ی مورد مطالعه، آثار زمین ساختی، ویژگی های رسوب و دینامیک جریان مسیر آبراهه‎ی رود کل، به‎عنوان‎ داده ها و نیز، پاره‎ای از شاخص های مورفومتریک به‎عنوان‎ ابزارهای مفهومی برای شناخت شیوه‎ی عملکرد آنها و زمین‎ساخت منطقه، مورد استفاده قرار گرفته است. سپس نتایج به‎دست‎آمده با انجام کار‎های میدانی گسترده، کنترل شده‎اند. علاوه‎براین، از عکس های هوایی، تصاویر ماهواره ای، نقشه های توپوگرافی و زمین‎شناسی، به‎عنوان‎ ابزارهای مقایسه‎ی زمانی و مکانی پژوهش استفاده شده است. نتایج به‎دست‎آمده از تحلیل داده ها با شاخص های مذکور و نیز، داده های ژئودینامیک نشان می‎دهد که منطقه‎ی مورد مطالعه تا اندازه‎ی زیادی از فعالیت های زمین‎ساختی کواترنری متاثر شده است با این تفاوت که میزان تاثیرگذاری فعالیت در همه جای آن یکسان نیست، بلکه قسمت‎های بالادست بیشتر از بخش‎های پایین‎دست دلتا از این فعالیت ها تاثیر می‎پذیرند.
    کلیدواژگان: رود کل، دلتا، شاخص های ژئومورفیک، دینامیک رود، نوزمین ساخت
  • حمید زارع ابیانه، مریم بیات ورکشی، صفر معروفی، علیرضا ایلدرومی صفحه 17
    برای بررسی کارایی شبکه‎ی عصبی مصنوعی در شبیه سازی تغییرات سطح ایستابی سفره‎ی آب زیرزمینی دشت ملایر، از اطلاعات هواشناسی ایستگاه های تبخیرسنجی در سطح دشت، حجم آب برداشتی از سفره و مقادیر سطح ایستابی آن استفاده شد. از این اطلاعات، به عنوان ورودی شبکه‎ی عصبی مصنوعی نوع پرسپترون چندلایه در چارچوب چهار ساختار اطلاعاتی استفاده شد. ساختار اول، شامل میانگین اطلاعات دمای حداکثر هوا، دمای حداقل هوا، حداکثر رطوبت نسبی هوا، حداقل رطوبت نسبی هوا و میانگین تبخیر در مقیاس زمانی ماهانه و ارتفاع سطح ایستابی ماه پیش بود. در ساختار دوم از اطلاعات سطح ایستابی در یک، دو، سه و چهار ماه پیش استفاده شد. در ساختار سوم، افزون‎بر اطلاعات ساختار شماره‎ی دو، میانگین سطح ایستابی ماه مورد نظر و میانگین سطح ایستابی ماه پیش هم به کار گرفته شد. ساختار چهارم، براساس میانگین سطح ایستابی ماه مورد نظر، میانگین سطح ایستابی ماه پیش و اطلاعات هواشناسی ماهانه تعریف شد. ساختار سوم با آرایش 1-4-4-6، به عنوان ساختار مناسب با 9/1 درصد خطا در مقایسه با مقادیر واقعی پیشنهاد شد که نشان دهنده‎ی اهمیت به کارگیری عوامل سطح ایستابی سال‎های گذشته، در ورودی شبکه‎ی عصبی است. اجرای مدل بهینه‎ی شبکه‎ی عصبی، افت سطح ایستابی را 18/1 متر، به‎ازای 9/1 درصد خطا برآورد کرد. جذر میانگین مربعات خطا در مدل بهینه‎ی شبکه‎ی عصبی با آرایش 1-4-4-6 بر مبنای قانون آموزش لونبرگ مارکوات و تابع محرک سیگموئید، در مقابل تغییرات واقعی سطح سفره 44/0 متر با ضریب تعیین 99/0 به‎دست آمد. با توجه به دقت مناسب مدل و روند کاهنده‎ی حاکم بر سفره، می‎توان استفاده از شبکه‎ی عصبی مصنوعی برای تصمیم گیری در مدیریت دشت را، به‎عنوان ابزاری با سرعت و دقت مناسب در شبیه سازی سطح آب زیرزمینی دشت ملایر، توصیه کرد.
    کلیدواژگان: شبکه‎ی عصبی مصنوعی پرسپترون چند لایه، آب زیرزمینی، مدل سازی، دشت ملایر، شبیه سازی
  • حسن لشکری، علی رضایی صفحه 29
    این پژوهش به مطالعه و مکان‎یابی مناطق مناسب برای کشت کلزا در شهرستان سرپل زهاب با استفاده از مدل‎سازی آماری پرداخته است. برای این کار، آمار بلندمدت هواشناسی شهرستان طی 15 سال، مورد استفاده قرار گرفته است. برای تهیه‎ی نقشه ها در سیستم اطلاعات جغرافیایی و نیز، تحلیل و مقایسه‎ی داده ها از ایستگاه های اسلام‎آباد غرب، روانسر و قصر شیرین استفاده شده است. با توجه به برآورده‎شدن نیاز دمایی، تاریخ‎های آغاز و پایان هر کدام از مراحل رشد کلزا به‎دست آمد. مقدار آب مورد نیاز و مقدار بارش رخ داده در مراحل رشد گیاه نیز، محاسبه شد. تمامی عناصر و عوامل موثر در رشد و عملکرد بهینه‎ی کلزا در مدل‎سازی مورد استفاده قرار گرفته که در هر مرحله، تعدادی از آنها حذف شدند. به کمک سیستم اطلاعات جغرافیایی برای هرکدام از متغیرهای نهایی اقدام به تهیه‎ی نقشه شده و سپس مدل نهایی مورد آزمون قرار گرفت و با مطالعات میدانی، نقشه‎ی نهایی با واقعیت منطقه انطباق داده شد. بر اساس نتایج به‎دست‎آمده در منطقه‎ی مطالعاتی، مقدار درجه/ روز مورد نیاز کلزا به‎خوبی برآورده می‎شود؛ اما در ابتدا و انتهای فصل رشد با تنش آبی مواجه می‎شود. بهترین و معنادارترین مدل Backward با متغیرهای میانگین سالانه‎ی بارش طی دوره‎ی رشد، میانگین دمای خاک طی دوره‎ی کاشت تا روزت، اولین یخبندان‎های پاییزه و میانگین بارندگی در دوره‎ی گل‎دهی و تشکیل غلاف به‎دست آمده است. با استفاده از آمار واقعی محصول کلزا در سطح شهرستان، مدل مورد آزمایش قرار گرفت که با احتمال 97درصد، نتیجه قابل اعتماد است. نتایج حاصل از مطالعات میدانی نیز با خروجی مدل همخوانی دارد، به‎گونه‎ای که 41 درصد از مساحت منطقه‎ی مطالعاتی برای کشت مناسب و 59 درصد ضعیف و نامناسب است.
    کلیدواژگان: مکان‎یابی، کلزا، سرپل زهاب، رگرسیون چند متغیره
  • غلامرضا روشن، فرامرز خوش اخلاق، مصطفی کرمپور صفحه 49
    هدف اصلی این پژوهش، اصلاح و بومی‎سازی مدل تبخیر و تعرق بالقوه‎ی مناسب برای ایران است. بنابراین، این پژوهش متشکل از سه مرحله‎ی اصلی: 1- خوشه‎بندی کشور براساس مولفه های آب‎وهوایی موثر بر تبخیر و تعرق؛ 2- آزمون نتایج استخراج شده‎ی تبخیر وتعرق با استفاده از رابطه های پیشنهادی و مقادیر تجربی (تشت تبخیر و لایسیمتری) و 3- اصلاح و بومی‎سازی معادله‎ی تبخیر و تعرق منتخب با استفاده از داده های مشاهداتی است. برای این پژوهش، از هشت متغیر آب‎وهوایی، میانگین اختلاف دما، میانگین حداقل، حداکثر رطوبت نسبی، مقادیر ساعت آفتابی، مقادیر بارش ماهانه، روزهای با بارش بالاتر از 10 و 5 میلی‎متر، فراوانی مقادیر رخداد سرعت متوسط باد بالای 5 نات بر ثانیه، برای یک دوره‎ی 26 ساله از 1980 تا 2005 و برای 64 ایستگاه سینوپتیکی و کلیماتولوژی کشور استفاده شده است. هدف از انتخاب این متغیرها، خوشه‎بندی ایستگاه های مورد مطالعه، بر اساس فراسنج‎های تاثیرگذار بر تبخیر و تعرق است تا بتوان پس از این مرحله، برای هر خوشه، براساس تشابه ایستگاه ها از نظر تبخیر و تعرق، ضرایب اصلاحی مشابهی را اعمال کرد. در انجام خوشه‎بندی، بهترین حالت به‎شکل شش خوشه‎ای معرفی شد. همچنین نتایج واسنجی چهار روش تورنث وایت، بلانی کریدل، جنسن هیز و‎ هارگریوز سامانی نشان داد که روش بلانی کریدل همخوانی بهتری با شرایط محیطی را ارائه می‎دهد. در انتها، با استفاده از داده های لایسیمتر، معادله‎ی بلانی کریدل برای ماه های مختلف هر شش خوشه‎ی مطالعاتی اصلاح و بومی‎سازی شد.
    کلیدواژگان: ارزیابی و استخراج مدل، داده‎های تجربی، تبخیر و تعرق بالقوه، ایران، خوشه‎بندی
  • شهرام بهرامی، محمد علی زنگنه اسدی، گوهر عزیزی پور، کاظم بهرامی صفحه 69
    لندفرم‎ها و فرایندهای ژئومورفولوژی از مهم‎ترین عوامل تاثیرگذار در حجم، پراکندگی و کیفیت مصالح ساختمانی، به‎ویژه سنگ‎دانه ها هستند. حوضه‎ی مورد مطالعه در شمال شهرستان خرم‎آباد و بخشی از واحد ساختمانی زاگرس چین‎خورده به‎شمار می‎رود. هدف این پژوهش، بررسی نقش اشکال و فرایند های ژئومورفولوژی در مکان‎یابی و کیفیت سنگ‎دانه ها در حوضه‎ی خرم آباد است. برای دست‎یابی به این هدف، نخست لندفرم‎ها و فرایندهای ژئومورفولوژی بر اساس تصاویر ماهواره‎ای کویک‎برد و مطالعات میدانی منطقه شناسایی شد. لندفرم‎هایی مانند واریزه ها، مخروط‎افکنه های جدید و قدیم، بستر های رودخانه‎ای جدید و قدیم مقادیر زیادی مواد هوازده و خردشده دارند که می‎توانند به‎عنوان مصالح ساختمانی استفاده شوند. برای بررسی کیفیت و مقاومت سنگ‎دانه ها، سه آزمایش مقاومت به سایش، مقاومت فشاری تک‎محوری و ارزش ضربه‎ای انجام شد. آزمایش سایش لس‎آنجلس برای دو نمونه‎ی 30 کیلویی از بستر قدیم و جدید رودخانه‎ی خرم‎آباد انجام شد. برای بررسی مقاومت فشاری سنگ‎دانه ها، آزمایش مقاومت فشاری تک‎محوری به‎روش (D2938: ASTM) در واریزه ها، مخروط‎افکنه های جدید و قدیم انجام شد. برای انجام آزمایش ارزش ضربه‎ای، 10 نمونه از سنگ‎دانه ها در لندفرم‎های واریزه، بستر‎های رودخانه‎ای جدید و قدیمی، مخروط‎افکنه های جدید و قدیمی، برداشت و بر اساس استاندارد BS-812 و با استفاده از الک شماره‎ی 8، میانگین ارزش ضربه‎ای در هر لندفرم به‎دست آمد. نتایج نشان می‎دهد که واریزه ها، مخروط‎افکنه های قدیم و جدید و بستر‎های رودخانه‎ای جدید و قدیم، مصالح ساختمانی با مقاومت مناسبی دارند. با وجود این، مقاومت سنگ‎دانه ها در واریزه ها نسبت به دیگر لندفرم‎ها بالاتر است. همچنین مخروط‎افکنه های قدیمی با توجه به تاثیر فرایند هوازدگی، مقاومت کمتری نسبت به مخروط‎افکنه های جدید دارند.
    کلیدواژگان: لندفرم‎های ژئومورفولوژی، فرایندهای ژئومورفولوژی، خرم‎آباد، مقاومت فشاری تک‎محوری، سنگ‎دانه
  • محمد طالعی، محمد سعادت سرشت، علی منصوریان، سمیه احمدیان صفحه 83
    هدف از این مقاله، توسعه ی یک مدل برپایه‎ی سامانه‎ی اطلاعات مکانی، به‎منظور پاسخ‎گویی به مسئله‎ی جست‎وجوی مسیر بهینه، برای تخلیه و انتقال سریع آسیب دیدگان حوادث ناگهانی به مناطق امن از پیش تعیین‎شده است. در بسیاری از حوادث، بهترین گزینه، جابه‎جایی افراد نجات یافته از بلایا که در منطقه‎ی تحت تاثیر مخاطره واقع شده اند، به مناطق امن است. پس تخلیه‎ی اضطراری، از نخستین مراحل مدیریت بحران به‎شمار می‎رود که باید در کمترین زمان ممکن انجام شود. چالش اصلی در مدیریت تخلیه‎ی اضطراری، هدایت مردم در مسیرهای بهینه برای دست‎یابی به مناطق امن مورد نظر است. از این رو، به‎دلیل لزوم سرعت در تخلیه‎ی منطقه‎ی تحت خطر، وجود یک طرح مسیریابی بهینه و کارآمد، بسیار ارزشمند است. مدل پایه برای مسیریابی بهینه در این پژوهش، دایجسترا است که با مقید شدن به پاره ای شرایط خاص، برای حادثه‎ی زلزله بهینه شده است. از آنجاکه فرایند مسیریابی برای تخلیه‎ی اضطراری آسیب‎دیدگان می بایست به‎کرات (برابر حاصل ضرب تعداد بلوک های ساختمانی در تعداد نواحی امن مربوطه) انجام پذیرد، مهم ترین ویژگی الگوریتم پیشنهادی سرعت بالای آن است. قابلیت و سرعت روش پیشنهادی، در یک شبکه‎ی مجازی شبیه سازی‎شده و همچنین در یک شبکه‎ی واقعی معابر شهری واقع در منطقه‎ی 7 شهرداری تهران، مورد آزمون قرار گرفته است. آزمایش‎های انجام شده حاکی از آن است که برای تعیین مسیر بهینه در یک شبکه‎ی واقعی شهری با 432 گره بلوک ساختمانی، 11 گره ناحیه‎ی امن و تعداد 1189 یال، تنها نیاز به زمانی در حدود 90 ثانیه است. قابلیت جست‎وجوی چند مقصدی مدل در یک بار اجرای آن، از دیگر ویژگی های روش پیشنهادی است.
    کلیدواژگان: مسیریابی بهینه، نظریه‎ی گراف، زلزله، GIS، تخلیه‎ی اضطراری
  • علیرضا ذبیحی، کریم سلیمانی، مرتضی شعبانی، صادق آبروش صفحه 101
    در بسیاری از مطالعات و بررسی های منابع طبیعی و کشاورزی، به‎دلیل عدم پوشش کامل ایستگاه های اندازه‎گیری نقطه‎ای باران ، برآورد بارش منطقه‎ای یا تخمین بارش در مناطق خشک میان ایستگاه ها ضروری است. بنابراین، آگاهی از میزان متوسط بارندگی در یک حوضه‎ی آبخیز، از عوامل اساسی در هیدرولوژی و طراحی سازه است. روش‎های مختلفی برای برآورد بارش وجود دارد که ازجمله‎ی آن می‎توان به روش‎های میان‎یابی اشاره کرد. در بیشتر موارد، یکی از روش‎های موجود دلخواه کارشناس انتخاب و مورد استفاده قرار می‎گیرد که ممکن است برآورد دقیقی نباشد. هدف از این پژوهش، مشخص کردن توزیع مکانی بارش سالانه‎ی حوزه‎ی آبخیز قم با استفاده از روش‎های زمین‎آماری و مقایسه‎ی روش‎های موصوف با یکدیگر است. برای این کار، پس از جمع آوری آمار و اطلاعات مربوطه و وارد کردن آنها در محیط نرم افزار GS+و ARC GIS نسخه‎ی 10، نقشه‎ی هم‎باران تهیه و آنالیز واریوگرام منطقه‎ی مورد مطالعه انجام شد. سپس برای ارزیابی روش‎های میان‎یابی از روش ارزیابی متقابل و دو عامل MAE وMBE استفاده شد. در این مطالعه، دو روش زمین‎آماری کریگینگ و عکس فاصله با توان های (1تا 3) برای برآورد بارش سالانه با استفاده از آمار سی ساله‎ی ایستگاه های باران‎سنجی در استان قم و اطراف آن مورد ارزیابی قرار گرفتند و برای ارزیابی دو روش فوق نیز، از معیار میانگین خطای مطلق (MAE) استفاده شد. نتایج این ارزیابی نشان داد که تغییرات بارندگی سالانه، بیشتر از مدل گوسی تبعیت می کند. در محدوده‎ی مورد مطالعه، روش کریگینگ با MAE برابر 22/30 میلی متر، مناسب‎ترین روش تخمین بارندگی سالانه است و روش عکس فاصله به توان یک با MAE برابر 23/32 میلی متر و عکس فاصله به توان دو با MAE برابر 55/33 میلی متر وعکس فاصله به توان سه با MAE برابر1/35میلی متر در رده های بعدی قرار می‎گیرند.
    کلیدواژگان: بارندگی، زمین آمار، میان‎یابی، کریگینگ و عکس فاصله
  • مصطفی کریمی احمدآباد، کامیار شکوهی رازی صفحه 113
    توفان های گرد و غبار یکی از انواع مخاطرات جوی هستند که در منطقه‎ی خاورمیانه، در طی سال، بارها امکان وقوع آنها وجود دارد. در دهه‎ی پیشین، رخداد این توفان ها فزونی یافته که بررسی علل این افزایش وقوع و سازوکارهای تشکیل آن، توجه پژوهشگران را به‎خود جلب کرده است. هدف مقاله‎ی پیش رو نیز، دست‎یابی به‎شیوه‎ی سازوکار تشکیل و فعالیت توفان‎های گرد و غبار مذکور است. در این مقاله، فراوانی توفان های دهه‎ی 80 و گرد و غبار تیرماه 1388 را با رویکردی اقلیم‎شناسی، همراه با در نظر گرفتن شرایط سطح زمین با استفاده از داده های شبکه‎بندی‎شده، شامل ارتفاع ژئوپتانسیل، سمت و سرعت باد، امگا و فشار سطح دریا از مرکز ملی پیش‎بینی های محیطی (NCEP)، داده های پوشش سطح زمین و خاک مورد استفاده در مدل اقلیمی منطقه ای (RegCM) مطالعه و بررسی شده است. نتایج این بررسی نشان داد که تشکیل کم‎فشار روی خلیج فارس و پیشروی آن تا جنوب ترکیه و مساعدت جریان‎های سطوح میانی و بالایی وردسپهر با استقرار ناوه روی این سطوح، در ساحل شرقی مدیترانه، سبب ایجاد گردش چرخندی در جنوب شرق سوریه، در سطح زمین روی زمین های بدون پوشش سطحی (پوشش گیاهی، سنگ‎فرش بیابانی) و دارای خاک سطحی ریزدانه و گچی شده است. قرارگیری شرایط ناپایدار جوی روی چنین خاک هایی، زمینه را برای تشکیل گرد و غبار فراهم کرده است. در طی روزهای بعد با حرکت به سمت شرق ناوه و عمیق شدن شرایط ناپایداری، گرد و غبار با حرکت شرق سوی خود از روی ارتفاعات زاگرس عبور کرده و تمام کشور، به‎استثنای جنوب‎شرق را تحت تاثیر قرار داده است. آن چیزی که در این توفان گرد و غبار مشهود است، همراهی شرایط گردش جو (ناپایداری با عمق مناسب) و شرایط سطح زمین (زمین بدون پوشش و خاک خشک و نرم) در ایجاد و فعالیت آن است.
    کلیدواژگان: گردش جو، ایران، خاورمیانه، گرد و غبار
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  • M. Yamani, H. Elmizadeh Page 1
    Introduction River instability needs to be evaluated on spatial and temporal scales. It must be recognized that rivers differ among themselves, and through time, and one river can vary significantly in a downstream direction. Morphology and behaviour of drainage network, to change from neotectonic is sensitive. Meanwhile meanders of delta levels are the most unstable areas of the rivers. Tectonic deformation causes change in channel slope, which in turn is responsible for variations in channel morphology, fluvial processes, and hydrological characteristics of a river system. River responses to active tectonics produce characteristic geomorphological features revealing surface deformation in any area. The study area is located in Hormozgan province and north coastal of Hormoz strait. Kol River with the formation of a relatively large delta, flows from north to south and arrive to the Strait of Hormoz. The purpose of this study is recognition evidence and evaluation of neotectonic in Kol river drainage network. In this paper rely on results based on field survey and index of geomorphic, morphology and riverbed changes, Kol River has been studied. Methodology For achieving results, geodynamic data National Cartographic Center related to Bandar Abbas station, index geomorphic such as drainage density (P), asymmetric factor (AF), sinuosity (S) and hypsometric integral (Hi) & time of concentration (Tc), topographic and geologic maps, aerial photos related to year of 1957 and satellite images of this area related to years of 2005, 2001, 1989 and 1977, as the main research tools and conceptual and model techniques were used. Methods are based on analytical and experimental method and technique of work is comparison during the transformation sequence of times. In the present work, first the morphometry of delta environment is investigated with considering the shape and the other main factors which control the morphometry of the river. At the second stage the data were imported in GIS environment to show the change model in the different places and times in a period of 50 years. To find out changes in the river bed, aerial photos and satellite images related to the study area in different time periods were examined. Then the data through field works by GIS (Arc Gis & ilwis) analysis and effect of tectonic analyzed. In this view, between redirected drainage and morphological feature and neotectonic affects has been relationship. Results and Discussion Range studied is located in south Zagros unit and fault existing in the region, are buried under the coastal sediments during the quaternary. Considering the evidence as changes multiple paths in different time periods, crossing the fault line, broad and narrow riverbed, It seems that under the influence of neotectonic active in the region. Sandstone and marl formations and very low slope of delta, caused the river does not have much stability and has repeatedly redirected during the past 50 years. Factors such as high slope of the upstream basins, plant cover poverty, low permeability formations of delta, being short time of concentration, precipitation intensity and the nature of showery precipitation, have caused occurrence of periodic floods in this region. These issues caused the river was not much stability and during the past half-century repeatedly to change the path (Figure 6). Based on data of geodynamic, displacement and tectonic activities of region is toward the north-eastern. This information indicates faults activity and tectonic movements in the region. Finding indicates continuity of the last neotectonic activity in the study area. Amount of activity is not the same everywhere, and upstream part of more than downstream of these activities is affected. Existing anomaly in the river, such as high density network of drainage, local development of meanders, being broad and narrow river bed and sudden redirects in different periods of time, including signs an active zone. Thus between neotectonic movements and changes in drainage network is a kind of interaction and reaction river systems is strongly influenced by this activity. Conclusion Results of research show that river still gain dynamic balance and is changing and transferring and create new screws. In general, changes are toward downstream. Management, set privacy and channel control, especially at the time of the occurrence of floods, is the most effective way to stability of river. also results from geomorphic indices and geodynamic data show that study area entirely influenced by neotectonic activities, But amount of influence is not the same in all region, as in the north-eastern part is higher. The present approach may be considered as an extended behaviour oriented approach for predicting morphodynamic evolution of rivers. The findings of this research can be useful for the study of impact of neotectonic on riverbed changes, the planning of construction, landuse planning, environmental protection, stability of river bed and generally sustainable environmental management. If we understand the various processes of change, prevention through good management and application of mitigation measures can be appropriately applied to the problem. Continued field measurements are the key to improving upon these procedures and add to the collective understanding of these complex and valuable river systems.
  • H. Zare Abyaneh - M. Bayat Varkeshi - S. Marofi - A. R._Ildromi Page 17
    Introduction Prediction of groundwater level is necessary for supply management and utilization of water. Groundwater Fluctuations is influenced by many variables. One of the most appropriate methods, the study of groundwater, is using computer models. Thus, understanding of ground water variation mechanism and its prediction is necessary for awareness of available groundwater. In this regard, artificial neural network models, due to lack of understanding of the physical nature of the problem in modeling a nonlinear system are capable. Studies in Iran show that, in spite of the importance of groundwater level prediction and intelligent neural network capabilities, few studies regarding water table simulations using artificial neural networks has been done so far. According to the necessities expressed purpose of this study is establish the relation between of groundwater level fluctuations associated with effective artificial neural network, in order to simulate and quantify associated water table fluctuations as an independent variable with various meteorological factors and hydro geology of Malayer plain.Methodology Malayer plain groundwater table located in Hamedan province was selected to evaluate the efficiency of artificial neural network for predicting water table changes. The collected data were based on similar studies and the effects of data on water table. They were used as inputs for artificial neural network on four structures. First data structure was including average maximum air temperature, minimum air temperature, maximum relative humidity, minimum relative humidity and evaporation monthly scale and height of water table of last month. In the second structure, water table data for every month from 1, 2, 3 and 4 previous months were used as inputs. Average of water table of mount and average of monthly water table plus the input of second structure were used as input for third structure. The inputs of fourth structure were mean of water table, data of last month and monthly meteorological data. Different patterns of artificial neural network were used on the basis of the four structure using Neurosolution software to estimate the water table. Results and Discussion The results showed that using water table parameters of previous years had the higher precision than other parameters on the prediction of water table. In other words, the results of the second and third data structures in which the input data kind was the same as output one better than two other structures were evaluated. In total, third structure topology 1-4-4-6 shows 6 neurons in the network input and middle layer 4 neurons is a suitable structure with 1.9 percent error compared with the actual values. The research showed that hydrograph of the plain during 1995 to 2006 was descending with the average of 1.2 meter annual loss and in total study period 14.5 m loss has experienced. Implementation of optimal neural network model consists of 6 neurons in the first layer of information; 1.18 m loss water table can be estimated. In other words, neural network with 1.9 percent average error rate was able to estimate withdraw from the table during studies 313 million m3 versus 319 million m3 of the actual harvested. Root Mean Square Error (RMSE) in the neural network optimal model 1-4-4-6 pattern based on Levenberg Marquet rule learning and the sigmoid function against table level actual changes was obtained 0.44 m with coefficient of determination 0.99 respectively. Error values resulting from the implementation of the proposed neural network model compared to other structures and similar studies have been done a very good accuracy. Conclusion Totally, it could be inferred that such variables entered the model structure based on structure of the number 3, the model and prediction water table changes is successful. Comparison of the optimum structure of neural network study with Izadi et al (2007) and Esmail verki et al (2004) in predicting groundwater levels, confirming the good performance of the network in this study with six input parameters to 15 parameters in the report and Izadi et al (2007) (R2 = 0.937) and 10 parameters in the study of sciatic Ismail et al (2004) (R2 =0.90) is. Meanwhile the number of input neurons in neural network under the terms of the speed and accuracy is more preferable (Abyaneh Zare et al, 2010).The suitable model and carefully downtrend governing table, using artificial neural networks for decision and management plain, as appropriate tool with speed and accuracy in predicting groundwater level in Malayer plain is recommended.
  • H. Lashkari, A. Rezaei Page 29
    Introduction In addition to provide oil and oil cake, implanting canola has an important effect on fixing foodstuffs and reducing soil erosion. This plant has a high compatibility with different climates and different soils and causes more in the next years of cropping. Sarpole Zahab area exceeds to 1300 km2 which 36/6% of that has the slope lower than 3°.The average of annual precipitation is 428 mm, the average of temperature is 20° cg and 20 days freezing weather in a year. The city has a suitable environmental and climate condition for implanting canola. But its implanting during the years was hopeless. Methodology For statistical analysis and planning use from daily data of Sarpole Zahab, Eslam Abad Gharb, Ravansar and Qasre Shirin stations. Base on calculation least data necessity is 10years, because of valid and use of whole data a 15years data period was gain. Germinate, flowering and sheath, Seeding of canola are more sensitive in growing period that use of daily data stations in the studied area and various probability we found out the time of phonology steps such as beginning dates, ending and number of each occurrence. the amount of water that plant need supplying with rain and probability of premature freezing weather in autumn and late freezing weather in spring was determined. Use of X2 test for determinate temporary or permanent of rainfall in flowering to sheath and make to Seeding of canola growing period. Based on scientific studies in, 20 effective environmental and climatic factors for overlapping were realized. Using climatic data of near station and by excel computing regression relationships of each element with altitude. Planning their maps based on DEM with GIS and TIN function if was having the meaningful relationships with altitude. Number and significance of classes was gain based on restriction and requirement of Canola. For planning of soil temperature during germinate to Rosete the mean temperature from 5 centimeter to half meter of soil deeps and hours of 03, 09, and 15 was obtained. For planning of premature freezing weather in autumn and late freezing weather in spring at first the dates were obtained calculate based on Julius dates then adaptations that Pierson3 have best adaptive with our data. Results and Discussion For determination the best area of cultivating canola in studied area with using multiple regression modeling, used from cropping data of district (kg/hec) as depended variable and environmental and climatic data effective on periods of growing as independent variable. By using the mentioned data in multi variations regression models, some effective climatic elements in best growing and function were determined, which are: the average of soil temperature in the duration of implanting up to growing, the first freezing time in autumn, annual precipitation during growing the plant and the average of precipitation during blossoming. Based on the results the best and the most meaningful model for estimating and precipitating crop in the studied area were backward. Based on gain equation and use from GIS and raster calculator function the layer were supplying before entrances in model and final plan was draw. By Pierson correlation coefficient determine the correlation between amounts of estimated product by model with amounts of real product. For determinate efficacy and significance each of used variables in final model compared the significant of independent variable by beta weight. Based on conclusion the best date for cultivating of autumn canola in studied area is the first to 15 Aban, also the growing period of canola is 170 days. Considering the daily data of rainfall shown that amount of rainfall for cultivating to germinate is less so that twice irrigation is necessary. Although the suitable rainfall were occurred in flowering to harvest time but canola damages is more severe than other growing periods that because of diffuse, showery, annual oscillation and don’t occur of 25 millimeter rainfall in same time. Based on X2 test conclusion occur the violent oscillation of rainfall in spearing for period of flowering to sheathe and seeding. So that the oscillation of rainfall is 8 to 123 for flowering period and 11 to 113 millimeter for seeding period. The correlation rate of cropping from canola farms in studied area with cropping that estimate by regression model is 97 percent. According to calculated amount meaningful of variables and result of other models the autumn freezing have determinant effect in site selection of suitable areas for implanting canola. Because of not considering the slope and altitude in providing the final map, it was corrected by using Topographic map 1/50000 and field studies applying GPS. Conclusion Considering the final map, the best places for implanting Canola is plain area. Also precipitation in the studied area is not enough, so not just in the end of growing season even in the beginning of growing season irrigating is essential.
  • Gh. R. Roshan, F. Khoshakhlagh, M. Karampur Page 49
    Introduction Iran is a dry land with very low precipitation. Annual rainfall is less than a third of the average rainfall worldwide. One of the ways of adjusting to drought in Iran, especially with agriculture is the optimal and sustainable use of water resources. Precipitation, surface water and ground water resources have to be used as efficiently as possible. This study would not be practical without first taking into consideration the exact requirements of water for agricultural fields in Iran. Knowledge on the evapotranspiration is very important in irrigation and drainage planning. Evapotranspiration is one of the key components of the hydrologic cycle and its calculation is important for a number of applications such as, the hydrologic balance of water, design and management of irrigation systems, simulation of the amount of products and design, and management of water resources. Methodology The key purpose of this research is to assess, modify and localise a potentially suitable evaporation and transpiration model which can be implemented for Iran. The research methodology focuses on three main parts: 1- Country clustering based on the climatological effect of evapotranspiration. 2- Testing the results of evapotranspiration using proposed relationships. 3- Modifying and localizing current evaporation and transpiration models with observed data. This research takes into account eight components, namely; average temperature difference, minimum average maximum relative humidity, the frequency of occurrence of average wind speeds above 5 knots per sec, the amounts of monthly rainfall, days with rainfall above 10 mm and 5mm, a 25-year record (1980 to 2005) of 64 synoptical and climatological stations in Iran. The purpose of selecting these components has been clustering the studied stations based on effective parameters of evaporation and transpiration in order to after this stage exert for each cluster equal modifying coefficients based on similarity of the stations in evapotranspiration process. Results and Discussion In this study, the findings suggest clustering the country into six main parts. Each cluster is based on its geographical and climatic characteristics. The first cluster is the arid to semi-arid regions of the central and south-east. In the first cluster the minimum evapotranspiration is 51 mm for January and the maximum 322 mm for July. The annual average evapotranspiration for the first cluster is 2119 mm. The second cluster is wet and mountainous regions of the north and west. In the second cluster, the minimum evapotranspiration is 21 mm for January and the maximum, 272 mm for July. The annual average evapotranspiration for the second cluster is 1584 mm. The hot region of the southern coasts is the third cluster and in this cluster the minimum evapotranspiration is 118 mm for January and the maximum evapotranspiration 265 mm for June. The annual average evapotranspiration (2291 mm) for the third cluster was found to be the highest. The fourth cluster is cold and dry regions of the north-east to cold and wet regions of the north-west. The minimum evapotranspiration for the fourth cluster is 14 mm for January with a maximum of 283 mm for July. The annual average evapotranspiration for the fourth cluster is 1596 mm ranking in third place amongst the other clusters. The fifth and sixth cluster is a combination of the wet to very wet regions of the north coasts. In the fifth and sixth cluster the minimum and maximum evapotranspiration is 28mm (for January) and 161 mm (for July) respectively. The fifth and sixth cluster has the lowest annual average evapotranspiration (1012 mm) of all the clusters. In future evapotranspiration amounts for base stations can be calculated using proposed relations and the result can then be compared with the results of other formulas for convection such as the Pearson’s formula. Overall, the result that will be extracted from the total average is calculated using Blaney Cridle's method which ranks first here with an average of 0.69. The methods of Jensen-Haise, Thornth-Waite, and Hargrives-Samani rank second to fourth respectively here. After selecting Blaney Cridle s model as the most suitable, this model was then calibrated using empirical evaporation data from lysimeter. Conclusion Results from clustering Iran based on the evapotranspiration component shows that the annual maximum of this component is allocated to the third cluster or hot regions of the southern coasts. This maximum potential evapotranspiration is likely due to the low latitudinal location of the stations and the near vertical radiation of the sun’s rays in these regions. In contrast, cluster 5 and 6 (wet to very wet regions of the north coasts) have jointly the lowest annual average evapotranspiration amount. This low evapotranspiration amount is likely due to the lower elevation (sea level) of cluster 5 and 6. In addition to the location of cluster 5 and 6 at higher latitudes may account for the cluster having the lowest potential evapotranspiration when compared with the other clusters. The result obtained from the correlation between the output values of Blaney Cradles’ index with the values of components of this index (mean daily temperature, minimum relative humidity, mean wind speed, sunshine hours) reveal that minimum relative humidity has the most effect in comparison with the other climatic factors in the amount of potential evapotranspiration for clusters 3, 5 and 6. In clusters 1, 2 and 4, this component was temperature showing more correlation with the values of potential evapotranspiration. It is recommended utilizing normalized data in future to obtain more appropriate correlations between climatic parameters with evapotranspiration.
  • Sh. Bahrami, M. A. Zangeneh Asadi, G. Azizipour, K. Bahrami Page 69
    Introduction Geomorphological Landforms and processes are of the most significant parameters that affect the volume, distribution and quality of construction materials especially aggregates. Some geomorphological landforms like river beds, river terraces, alluvial fans and taluses have large amounts of weathered rocks and sediments that are appropriate for aggregate exploitation. Geomorphological processes like physical and chemical weathering also affect the quality of aggregates. Aggregates, a type of construction materials, are produced from sand and gravel and weathered bedrock that can be used for concrete, road pavement and other construction purposes. These materials have been weathered, detached from the parent rocks, transported and finally deposited in geomorphological landforms. Study area, Khoramabad catchment in north of town of Khoramabad with a drainage area of 442.19 km2, is part of Zagros Folded Belt. The aim of this research is to evaluate the effect of geomorphological processes and landforms in the formation, distribution and quality of aggregates. Methodology The purpose of this research is to evaluate the effect of geomorphological landforms in the distribution of aggregate and to assess the effect of geomorphological processes in the quality of aggregates. To achieve the purpose of this study, at first, Geologic map of the study area at a scale of 1:250000 and the topographic maps at a scale of 1:50000 from Iranian National Geography Organization top sheets were used to derive lithology and DEM of study area. Geomorphological landforms and processes were recognized by Quick bird satellite images. Precise field works and observations also have been carried out for the identification of landforms and processes. To study the quality and strength of study area aggregates, resistance to abrasion (Los Angeles test), uniaxial compressive strength and Impact Value of aggregates have been done. To determine the aggregate resistance to abrasion, Los Angles test (based on National Standard number 448) of 2 samples (30 kilograms for each sample) of aggregates in old and new river beds was performed. Uniaxial Compressive Strength test has been done based on ASTM D2938 method. Three samples of rack fragments with a dimension of 20 × 20 × 15 centimeters were obtained in talus, old and new alluvial fans. Two cylindrical cores (two-inch) were prepared for each sample and then Compressive Strengths of samples were determined in wet and dry conditions. The aggregate Impact Value test has been done based on sieve No. 8 for 10 samples in taluses, alluvial fans and river beds. Results and Discussion Result of this study shows that landforms such as taluses, old and young alluvial fans and old and young river beds have a lot of weathered and crushed materials that can be used as aggregates. Processes of physical weathering such as thermoclastic and cryoclastic processes as well as tectonic joints play an important role in the production of building materials especially in taluses in the base of steep ridges. To study the quality and strength of study area aggregates, resistance to abrasion (Los Angeles test), uniaxial compressive strength, and aggregate Impact Value tests were carried out. Results of Los Angeles test represent that aggregate abrasion of two samples in old and new river beds are 24% and 18% respectively that show rather high quality of aggregates in mentioned landforms. Uniaxial compressive strength of aggregates for 3 samples in new alluvial fans, old alluvial fans and taluses are respectively 641, 343 and 778 kg/cm2 in dry condition and 495, 249 and 720 kg/cm2 in wet condition. Results of aggregate Impact Value tests show that mean of this test in taluses, new river beds, old river beds, new alluvial fans and old alluvial fans are 11.05, 11, 11.95, 13.2 and 13.8 percent respectively. Overall results of mentioned tests reveal that geomorphological landforms such as taluses, old and young alluvial fans and old and young river beds have construction materials with appropriate quality. Also, because of more weathering in old alluvial fans, the strength of construction materials of old alluvial fans is weaker than those of new alluvial fan. Conclusion Aggregates are produced from sand and gravel and weathered bedrock that can be used for concrete, road pavement and other construction purposes. Location, volume and quality of aggregates are often important for engineers. Results of this study reveal that location and volume of aggregates are efficiently affected by the geomorphological landforms. Aggregate quality and resistance to abrasion are strongly related to geomorphological processes like degree of weathering. For example, because of more weathering in old alluvial fans, the strength and therefore quality of aggregates of old alluvial fans are lower than those of new alluvial fan. Some processes like karstification have negative effect on the aggregate quality because it can result in the formation of voids and cavities in rock fragments. On the other hand, some processes like physical weathering can prepare fresh materials as appropriate aggregates. Thus, geomorphological mapping, identification of landforms and processes, determining the degree of weathering and paleogeomorphological appraisal of areas are of great important in better understanding and exploitation of aggregates.
  • M. Taleai, M. Saadatseresht, M. Mansourian, S. Ahmadiyan Page 83
    Introduction Many researchers have worked on the issue of crisis management due to natural disasters such as earthquakes and hurricanes (Lindell & Prater 2002; Ardekani 1992). Accordance with the views Chiu & Zheng (2007), making decisions regarding emergency evacuation due to unexpected events, should include the following aspects: • Destinations, the victims should be moved there, which can be temporary accommodation in tents, medical services or secure areas, and • Consuming time to get the destinations by the victims that should be the shortest. Temporary accommodation of earthquake victims includes the following steps: (Naghdi et al., 2006; Saadatseresht et al., 2007) • Phase 1: Searching for some safe areas based on some constraints, such as a minimum risk, adequate capacity, proper distribution, access to adequate drinking water etc. • Phase 2: Determining the optimal path between each building block, located in the disaster area, and the safe areas based on several factors. • Phase 3: Selecting the optimum safe area for each building block in an optimization process based on two criteria: traffic capacity and the minimum cost (the shortest) to get the safe area. This paper presents a suitable algorithm for performing the 2nd phase of the process discussed above. This paper is developed a shortest path algorithm based on geographical information system (GIS) for quick discharge and transfer injury disaster victims to predetermined safe areas. Methodology Dijkstra's algorithm, introduced by Dijkstra in 1956 and published in 1959, is a graph search algorithm that solves the single-source shortest path problem for a graph with nonnegative edge path costs. For a given source vertex (node) in the graph, the algorithm finds the path with lowest cost (i.e. the shortest path) between that vertex and every other vertex. This is asymptotically the fastest known single-source shortest-path algorithm for random directed graphs with unbounded nonnegative weights. The general idea of the proposed algorithm for optimum route determination for emergency evacuation issue is based on the Dijkstra. Dijkstra is improved with defining some particular conditions regarding earthquake disaster management. Proposed algorithm can find shortest path (optimum path) among all building block (as place of victims) and all safe areas (as evacuation destinations). Since short path finding process for emergency evacuation should be repeated numerously along the network (equal to the product of the number of building blocks in the number of safe areas), most important features of the proposed algorithm is its high speed. Results and Discussion Capabilities and speed of the algorithm has been tested at both virtual and real urban network located in district 7 of Tehran. To evaluate the efficiency of the proposed method of this paper, the algorithm was examined in a real urban network. Test area within the northwest part of the seven regions of Tehran. Some data include building blocks, urban streets and green spaces (as safe areas for emergency evacuation), urban population was used. Selection of the safe areas has been done based on suggestions raised in Earthquake Studies in Tehran by JICA. After creating topology, a real network with 432 building-blocks’ nodes, 11 safe areas’ nodes and 1189 edges was established. The results show that determining optimal path in the real network of, only required about 90 seconds. To be ensuring about the accuracy of the algorithm some tests have been done on both virtual and actual network. First, with a displacement of points of origin and destination, go and return path between two vertices of the network was searched independently by the algorithm and observed that the paths completely match. After repeating this test, accuracy of the algorithm was verified. In the second test, the overall performance to find global and local optimum path between two vertices was examined. In the third test, simultaneous performance of the proposed algorithm for searching optimal paths between a source (building blocks) and multiple destinations (safe areas) was investigated. All the tests were verified performance of the proposed algorithm. Conclusion In this paper after reviewing several methods, that have been used for finding the optimum path in a discrete network, a method based on modification of Dijkstra algorithm was presented. For increasing the speed of the proposed method, some constraints were added to Dijkstra. According the test has been done in both simulated and real network; we found the proposed method advantageous for optimum route determination problem. Multi-destination search capability to find shortest path to all safe areas from each building blocks by only one run of the algorithm, is other characteristics. Decision making regarding the emergency evacuation when we consider that all affected people should be in a transport network with limited capacity is very difficult. Therefore, regardless of other issues involved in emergency evacuation problem, preparing a time schedule for evacuating people living in each block to avoid simultaneous presence of all injured at the site and creating traffic according to the limited capacity of urban streets, are the issues that require further study. Furthermore, the proposed algorithm can be used for other applications such as determining the optimum route for navigation activities.
  • A. Zabihi, K. Solaimani, M. Shabani, S. Abravsh Page 101
    Introduction The rate of average precipitation specifically its regional average is one of the significant factors in the field of natural resources studies. There are different estimation methods to estimate the precipitation such as geostatistic technique. This method is important with concerning to correlation and data spatial structure. Spatial location of the samples can be analyzed with the purposed quantity together. In other word the relationship between different quantitative rates is required to the community, samples distance and their situation dime. This spatial relationship (distance and community) is possible to describe in mathematical method between the rates of quantities in sampled community. In this research Kriging and inverse distance methods with power of 1 to 3 used to investigate the annual precipitation rate in Qom province. Methodology The study area This study is focused on Qom province with an area of 1123800 hectares. For the data control and their accuracy 12 climatology stations were used as the coved points in the study area. After determining the stations, data homogeneity is sorted based on run test to make sure data quality and also the recorded data series homogeneity. According to table 1 the average rainfall was extracted based on IDW method for 30 years from 1978-2007 in GS+ environment.For that reason the related data and information were collected for the software environment of GS+ and Arc GIS v.10 to produce isohyets map and analysis of variogram. The cross validation, MAE and MBE parameters techniques were used to validate IDW methods. Analysis of Variogram Simi-variogram method is one of the sensible methods for the spatial variations. Calculation of semi-variogram curve is the most significant operation of geostatistical which based on variation of two points in distinctive distance. Method and criteria of validation Cross validation technique and statistical two parameters of MAE and MBE were used to validate the IDW methods. In this study different models such as linear, spherical were used to calculate Kriging coefficient as a geostatistical estimator. Results and Discussion For investigation on spatial structure of the annual rainfall, the rate of empirical semi-variogram was calculated to draw the curve which processed with a appropriate model (table 2).Conclusion According to the gained results in this study Kriging method is specified with the highest precision (MAE of 30.23 mm) and the lowest precision is related to the inverse distance with power 3 (MAE of 35.5 mm) which are shown as follow: Kriging method >〖IDW〗^3>〖IDW〗^2>〖IDW〗^1Statistically the extracted results from the selected stations with 30 years recorded data can be concluded that the form of rainfall is distributed with 210, 205, 180 and 165 millimeters in Khalajestan district in west, Kahak district in south, Salafchagan in south west, central part and North West parts respectively.
  • M. Karimi Ahmadabad, K. Shakouhi Razi Page 113
    Introduction In some regions, particularly the Middle East, the dust storms occur with high frequency. Since the past decade, the occurrence of dust storms has increased in this region (Kutiel & Furman, 2003: 419). Several factors are involved in the creation of the dust storms, but the main factors are circulation of the atmosphere and earth surface. Synoptic studies have shown that low and high pressure (especially dynamic), and the vertical motion of air are the main causes of dust storms in the Middle East (Omidvar, 2006; Lashkari, et.al., 2008; Mehrshahi, 2009; Tavousi, 2010). Daily mean of dust storms in Iran, especially Khuzestan in the warm season is more than other seasons, and the highest frequency has been observed in the Zabol (Raeespour, 2010; Farajzadeh, 2011). The frequency of these storms will be increased after droughts, because the ground is dry and has less vegetation (Miri, et.al., 2009). To investigate the mechanism of dust storms in Middle East, dust storm occurrence in first days of July 2009, that is the biggest storms, has been elected, in this study interaction between atmospheric circulation and earth surface properties including soil moisture, land cover and soil type has been studied by a synoptic approach. Methodology Dust storm classified based on the origin. The Storm of Syrian origin, has been selected for this study. The Satellite images and Synoptic maps showed that period of this storm is 30 June to 9 July and south of Syria, Iraq and Iran influenced by dust storm. In this research, several types of data are used including zonal and Meridian wind, Geopotential height, Omega, Precipitation, sea level pressure, soil moisture from NCEP, Land use from RegCM/3 Model and satellite images (MODIS). The method of the research is the synoptic approach. Results and Discussion This dust storms caused by the development of Persian Gulf low pressure and extension of a trough to south of Turkey that create cyclonic circulation in the surface of southeastern Syria. These mentioned Conditions and also wind speed increasing in surface, low level of troposphere with location of the trough in the middle and upper level of the troposphere alongside dry and Gypsiferous soil have effects in the creation of dust storm. After creation of the dust storm by surface and low level instability over desert of Syria on the 1 July, then it spread over Iraq due to the development and extension of instability caused by the trough in middle and upper level and northwest wind. Through shifting to the east and changing the wind direction and also more important instability through troposphere, dust storm on the 4 July passed from Zagros Mountains and spread over Iran. In the next days, dust storms moved to east and northeast and influenced almost of Iran. This condition Remained to July 9 over Iran. Conclusion Maximum radiation and minimum precipitation in warm season caused the negligible soil moisture in this region by. The soil of dust storm area, except a very small of margin River in southern Syria and northwest of Iraq is soft, fine grain, Gypsiferous, and without any cover. Middle East at the warm season is dominated by subtropical high pressure and subtropical jets stream, but the circulation of the atmosphere during dust storm, shows that a low pressure extends over Persian Gulf and south of turkey. This condition causes the formation of cyclonic circulation in the East of Syria on 1 July. Wind speed Increasing, cyclonic circulation, dry soil and lack of coverage, provided the conditions for removing the soil particles. Due to the extended ground surface's low pressure and instability of low level of troposphere, dust storm enhances and moves to south-southeast over Iraq and Persian Gulf. But unstable layer is shallow, and then storm has not passed from the heights of West Iran. Dust storm passed from Zagros Mountains and entered to Iran due to moving trough from west to east of Iran and development of instability on July 4. In the next day (5 July) a cyclonic circulation has been created in central Iran, this circulation and extended instability caused the spread of dust over almost of Iran exactly southeastern regions. This study shows that both of atmospheric circulation and condition of ground surface are important in creation of dust storm in the Middle East.