نتایج جستجو برای: dust and sand storms

تعداد نتایج: 16843625  

Journal: :جغرافیا و مخاطرات محیطی 0
محمدرضا محمدپور پنچاه محمدحسین معماریان سید مجید میررکنی

introduction one of the factors that affect the climate of arid and semi-arid areas is dust storm. numerical models are new methods for evaluation of dust storms which can also be used for forecasting dust storms. weather patterns that lead to dust outbreaks can be simulated using computer models that support a wide range of simulations related to the long-range transport, dispersion, and depos...

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In this study, the changes in the Khorramabad storm in the period of 1952 to 2015 have been investigated. For this purpose, data from meteorological codes 06 and 07 were received from the Meteorological Organization of the country, and after identifying the days of winding with dust storms and calculating their monthly frequency, monthly, seasonal and annual time series were analyzed. In this s...

Journal: Desert 2012
A. Miri A. Pahlavanravi H. Ahmadi M.R. Ekhtesasi

Dust storms are catastrophic natural disasters that beside other disasters frequency occur in the arid and semiaridregions worldwide. Drought occurrence, climate aridity, dryness of the Hamoun Lake cause strong winds to below.These conditions have been prepared for dust storms in Sistan region. The damages to Sistan society have beenmeasured using different criteria. The result shows that, peak...

2013
Qunfeng Dong Yingle Li Jiadong Xu Mingjun Wang

Based on the forward scattering amplitude function for sand particle under the Rayleigh approximation, the calculation models of microwave attenuation and phase shift due to sand and dust particles is given in terms of lognormal size distribution. The model shows that attenuation and phase shift are found to be dependent on visibility, frequency and complex dielectric constant. Obtained results...

2006
GUO Ni

In order to detect the scope and the intensity quantificationally, the spectrum characteristic of sand and dust storm was analyzed in detail by using several MODIS data; bands that can distinguish sand and dust from cloud and surface were detected; two indices for determining the scope and intensity of sand and dust storm were found out, and were tested in several storms. Our study result shows...

Journal: :desert 2012
a. pahlavanravi a. miri h. ahmadi m.r. ekhtesasi

dust storms are catastrophic natural disasters that beside other disasters frequency occur in the arid and semiaridregions worldwide. drought occurrence, climate aridity, dryness of the hamoun lake cause strong winds to below.these conditions have been prepared for dust storms in sistan region. the damages to sistan society have beenmeasured using different criteria. the result shows that, peak...

Journal: :desert 0
a. pahlavanravi faculty of natural resources, university of zabol, zabol, iran a. miri faculty of natural resources, university of zabol, zabol, iran h. ahmadi islamic azad university, science and research branch, tehran, iran m.r. ekhtesasi faculty of natural resources, university of yazd, yazd, iran

dust storms are catastrophic natural disasters that beside other disasters frequency occur in the arid and semiaridregions worldwide. drought occurrence, climate aridity, dryness of the hamoun lake cause strong winds to below.these conditions have been prepared for dust storms in sistan region. the damages to sistan society have beenmeasured using different criteria. the result shows that, peak...

2005
Zhan Guo

The frequent yellow-dust storms in China in recent years have widely disrupted economic activities, destroyed farm land, and created a great hazard to human health. Meanwhile, there are various programs with vast investment from different levels of governments In China to prevent, and mitigate the impact of yellow-dust storms. However, little is known about the casual factors, socioeconomic imp...

Journal: :فیزیک زمین و فضا 0
فرحناز تقوی استادیار، گروه فیزیک فضا، موسسه ژئوفیزیک دانشگاه تهران، ایران الهه اولاد دانشجوی کارشناسی ارشد هواشناسی، گروه فیزیک فضا، موسسه ژئوفیزیک دانشگاه تهران، ایران طاهر صفرراد دانشجوی دکتری اقلیم شناسی، دانشکده جغرافیا دانشگاه تهران، ایران پرویز ایران نژاد دانشیار، گروه فیزیک فضا، موسسه ژئوفیزیک دانشگاه تهران، ایران

mineral dust can directly affect the solar and terrestrial radiation in both visible and infrared (ir) spectral regions through scattering and absorption processes. due to specific optical properties of dust particles, satellite observed radiances carry the spectral signatures of dust particles that are different from molecular, cloud, and underlying surface. based on these differences, various...

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