نتایج جستجو برای: wind erosion index
تعداد نتایج: 504575 فیلتر نتایج به سال:
منطقه ی شهریار در دهه های اخیر شاهد افزایش روزهای غبارآلود بوده است. به منظور منشاء یابی گرد و غبار و اثرات پوشش زمین در وقوع فرسایش بادی و روزهای غبار آلود این منطقه از تصاویر ماهواره ای لندست و نقشه های تراکم پوشش گیاهی استفاده شد. نتایج نشان داد که پوشش گیاهی با تراکم بالای 75% ، از بین رفته و بیشتر مساحت منطقه دارای تراکم بسیار پایین (کمتر از 25%) است. جهت باد غالب در ایستگاه شهریار شمال غر...
One of the main causes of air pollution in the arid areas of world, especially in Iran, is the increase of the PM10 concentration. The main objective of this research is to identify the most important climatic factors affecting the change of PM10 concentration near Yazd-Ardakan plain and its relation with wind erosion occurrence during the period from 2012 to 2017. For this purpose, the monthly...
In order to recognize the wind erosion situation of a region, the survey of its windiness is not sufficient and the physical characteristics of earth are of importance too. In fact, the outbreak of dust storms in a region is due to the sensitivity of earth and domination of wind in that region. In this investigation we have tried to find a way for determining the regions in which a dust storm i...
erosion by wind is one of the most important factors in desert environment. prevailing winds can shift sand dunes and affect their accumulation. also, wind regime determines the direction of sand dune mobility. the aim of this research was to investigate sand drift potential using sand movement models. for this research, wind data between 1986 and 2005 from the meteorological station of yazd we...
several models have been developed to estimate land degradation rate and evaluate desertification severity. this study attempts to apply the medalus (mediterranean desertification and land use) model by considering existing conditions in the hamoun wetland, located in south-eastern iran. at first identification of the main factors affecting the desertification phenomenon was attempted, based on...
different types of sediment trap have been introduced so far to be used in erosion measuring stations, each with its own advantages and disadvantages in trapping aeolian particles. these traps have different collection and retention efficiency due to aerodynamic conditions. some characteristics such as isokinetic feature of the trap, collection efficiency, time needed to download sediment, capa...
Extended abstract 1- Introduction Urmia Lake as the largest domestic lake in Iran is drying. Climate change in the northwest of Iran, rainfall reduction and evaporation, due to the increase in average temperature in the Northwest of the country accompanied with the involvement of human factors such as dam construction, have caused an irreparable environmental hazard in the northwestern of Ira...
For the study of field wind erosion and the design and evaluation of wind erosion control techniques, detailed observations of soil particle transport and vertical destribution of eroded soil particles are needed. The objectives of this study were: 1) To describe one device for soil transport particle measurement, i. e. the BSNE sediment catcher and 2) To assess vertical distribution of wind–er...
IVind ttiimel tests on silty textured loessial soils throtigbout the Cohimhia Plateau of eastern Wa.shiitg{on slate and northern central Oregon were used ro define soil erndibiltiy for wind erosion predictions. Aggregate and primary particle size distributions were determined hy common techniques and correlated wiih the wind tunnel erosion values. Dry aerodynamic particle sizing by a laser meth...
For the study of field wind erosion and the design and evaluation of wind erosion control techniques, detailed observations of soil particle transport and vertical destribution of eroded soil particles are needed. The objectives of this study were: 1) To describe one device for soil transport particle measurement, i. e. the BSNE sediment catcher and 2) To assess vertical distribution of wind–er...
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