نتایج جستجو برای: 500 hpa levels besides wind components u and v and sea level pressure

تعداد نتایج: 17165618  

Journal: :جغرافیا و مخاطرات محیطی 0
برومند صلاحی مهدی عالی جهان

introduction precipitation, an intrinsic part of nature, is essential not only for the survival of human but also for that of plants and animals. yet, this valuable natural phenomenon can also jeopardise human life, flora and fauna. torrential rains are sudden events that wreak havoc in iran and other parts of the world. in recent years, due to man's abuse of nature and disruption of environmen...

Today, dust and dust storms are among the most important environmental problems in the world and Iran, in particular. This study is conducted to identify synoptic patterns of the dust storms in Ardabil Province (Iran) and monitor the origin and pathway of its places. The study period is 34 years for1979 to 2013. The data used in this work are from synoptic stations of Ardabil province and the N...

Journal: :پژوهش های جغرافیای طبیعی 0
حسین ملکوتی استادیار دانشکدة علوم و فنون دریایی دانشگاه هرمزگان محمد پاخیره زن دانشجوی دکتری فیزیک دریا، دانشکدة علوم و فنون دریایی دانشگاه هرمزگان وجیهه السادات حسنی کارشناسی ارشد هواشناسی، دانشکدة علوم و فنون دریایی دانشگاه هرمزگان

introduction shamal winds recognized as a climate regime with a common occurrence in the persian gulf makes periodically adverse weather conditions in this region. among the phenomena occurring under the influence of shamal wind, we can mention dust storms, low-level winds and turbulent marine conditions (rao, 2003). shamal winds are categorized into two types, winter shamal and summer shamal. ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز 1390

building on previous studies on the effectiveness of different types of written corrective feedback, the present study aimed at investigating whether direct focused corrective feedback and direct unfocused corrective feedback produced any differential effects on the accurate use of english articles by efl learners across two different proficiency levels (low and high). in current study, the par...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - پژوهشکده ادبیات 1389

the present study reports an analysis of response articles in four different disciplines in the social sciences, i.e., linguistics, english for specific purposes (esp), accounting, and psychology. the study has three phases: micro analysis, macro analysis, and e-mail interview. the results of the micro analysis indicate that a three-level linguistic pattern is used by the writers in order to cr...

Journal: :محیط شناسی 0
عباسعلی ولی استادیار بیابان زدایی، گروه علوم مهندسی بیابان، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه کاشان، کاشان، ایران سجاد خاموشی کارشناسی ارشد بیابان زدایی، گروه علوم مهندسی بیابان، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه کاشان، سید حجت موسوی استادیار ژئومورفولوژی، گروه جغرافیا و اکوتوریسم، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه کاشان، کاشان، ایران فاطمه پناهی استادیار بیابان زدایی، گروه علوم مهندسی بیابان، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه کاشان، کاشان، ایران احسان تمسکی کارشناسی ارشد بیابان زدایی، دانشگاه هرمزگان، بندرعباس، ایران

introduction dust storms, one type of dust event, are in most cases the result of turbulent winds, including convective haboobs, which raise large quantities of dust from desert surfaces and reduce visibility to less than 1 km. this dust reaches concentrations in excess of 6000 mg m3 in severe events. the major dust source regions are areas of arid and hyper-arid, with mean annual rainfalls of ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه رازی - پژوهشکده علوم 1388

heteropoly acids (hpa) and their salts have advantages as catalysts which make them both economically and environmentally attractive, strong br?nsted acidity, exhibiting fast reversible multi-electron redox transformations under rather mild conditions, very high solubility in polar solvents, fairly high thermal stability in the solid states, and efficient oxidizing ability, so that they are imp...

Introduction Because the occurrence of precipitation is directly related to the humidity in the atmosphere or precipitation systems, the study of humidity in the form of precipitable water and the transfer of water vapor is considered in atmospheric studies. Convergence Moisture flux is effective on precipitation, so its effect is much greater in the warmer months, especially in the lower at...

بیتار, محمد, جعفری, فرزانه, لشکری, حسن, پژوه, فرشاد,

The temperature as an indicator of heat intensity is one of the basic elements of knowing weather. The frost is a condition when the air temperature is less than 0 c Due to the geographical possition of Iran, spring is a season that plants resume a new life after leaving a pause in a periode of the growth. At the beginning of such a periode emerge of sudden cold cause loss bloom (in the case of...

Journal: :جغرافیا و مخاطرات محیطی 0
پیمان محمودی محمود خسروی سید ابوالفضل مسعودیان بهلول علیجانی

introduction although temperatures in 0 and below 0 c° in the cold season of the year and mid latitudes are not necessarily considered an extreme phenomenon, but their long-term durability in a widespread area or their sudden occurrence in the beginning and end of the cold season can make this faetor an extreme extent phenomenon. the extreme phenomena are resulted from interaction between large...

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