نتایج جستجو برای: dust storm
تعداد نتایج: 58433 فیلتر نتایج به سال:
the aim of this study is to determine the area affected by dust storms in different wind speeds using satelliteimages. in the first step, windy conditions of the sistan plain were analyzed using wind statistics data. next, fivestormy days of zabol city, indicating different wind speeds and horizontal visibilities during those storms, wereselected. then, high temporal resolution modis data was u...
Introduction: In recent years, frequency and intensity of dust storms have been increased because of human destructive activities and caused significant loss in different aspects of hygienic and health, environmental and socio-economic sections. Therefore, detection and trace of dust storms in shortest time is the first effective step in preparation and implementation of strategic and operation...
Vegetation is one of the most important components of ecosystem, which plays an important role in protecting soil and preventing its rise. So, monitoring and evaluating its changes in planning to control the dust storm is effective. The purpose of this study was to investigate the changes of vegetation in the internal and external dust storm sources of Kermanshah province and dust extension are...
Wind erosion is the most important geomorphic process and the main cause of the landscape change in arid and semi-arid areas. This paper focuses on the Dust Storm Index (DSI) with the aim of monitoring wind erosion in Central Iran using meteorology data. The trend of standardized DSI and its three factors which are sever dust storm, moderate dust storm and local dust events were studied using M...
In recent years, the frequency of dust storm is rising. Dust storm can impact the climate changes and cause great damages to people. It is very necessary to monitor the disasters accurately. In this paper, a dust storm process occurred in April, 2006 has been monitored. According to the reflect and absorb characteristic of dust storm, the scope of dust storm is extracted successfully;and the in...
the aim of this study is to determine the area affected by dust storms in different wind speeds using satelliteimages. in the first step, windy conditions of the sistan plain were analyzed using wind statistics data. next, fivestormy days of zabol city, indicating different wind speeds and horizontal visibilities during those storms, wereselected. then, high temporal resolution modis data was u...
Introduction: Dust storm is one of the air pollutants in desert areas that have damaging effects on environmental ecosystems. This phenomenon usually happens when severe winds occur in arid areas which are accompanied by the ascent of dust particles to the upper layers of the atmosphere. HYSPLIT model can assist in detecting the path of dust entering the stations. In addition, synoptic patterns...
Monthly mean air temperature and precipitation data, monthly dust storm frequencies (times of dust storm occurrences) of 107 stations in North China were analyzed to clarify the relationship between the climate change and dust storm occurrence. Arid regions of North China were divided into five and trends of dust storm occurrence and climate changes showed different patterns for these regions, ...
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...
dust storms are known as hazardous problems in western part of iran. iraq is one of the main sources for dust storm arriving to the western part of iran. the radial basis function network model (rbfn) has been used to assess wind erosion hazards in the source area of dust storms over several western iranian cities. normalized difference salinity index (ndsi) was used to determine the changes in...
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