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Professor Kamal Omidvar, Miss Nesa Sepandar,
Volume 18, Issue 49 (3-2018)
Abstract

In this study, the dust situation in 6 synoptic stations of Kermanshah province was investigated in the period 1987-1992. To study this phenomenon, dust days were extracted in 2009 with code (06) from the current air index. Then data from different bar levels were taken from the National Oceanic and Atmospheric Organization (NCEP / NCAR) database and maps were plotted in the Grads software. Finally, through the processing of MODIS satellite imagery, with the application of the brightness temperature index, round detection and the dust was made and its territory expanded. The results of the study showed that at low ground level, when the European high-pressure system retreated to the north and west, Sudan's low pressure existed in the eastern Mediterranean, and the system moved southwest to the northeast, and when they entered, the disturbance zone is caused due to the lack of moisture in the dust, the main sources of dust in the province of Kermanshah include the deserts of northern Arabia, southern Iraq, and somewhat north of the sub-Saharan Africa.

- Nesa Sepandar, Professor Kamal Omidvar,
Volume 21, Issue 61 (6-2021)
Abstract

In this study, we tried to identify the sources of moisture and its direction of heavy rainfall in south and southwest of Iran by using a new algorithm based on atmospheric rivers. For this purpose, daily rainfall of 17 synoptic stations in the period 1986 to 2015 in south and southwestern Iran that have a common time span and fully cover the study area is used.Also from the data set of the National Center for Environmental Prediction / National Center for Atmospheric Research (NCEP / NCAR) European Mid-Term Forecast Center (ECMWF) and ERA-interim data with spatial resolution of 0.75 It was used at 0.75 latitude and longitude with 6 hour resolution. The variables used are integrated water vapor (IWV), specific humidity (q), and orbital and meridional components (u, v). In this research, an algorithm based on the calculation of Vertical Horizontal Vapor Transfer Integral (IVT) is used to identify and navigate atmospheric rivers. The results show that the main source of rainfall moisture is in south and southwestern Iran, south of Red Sea and Gulf of Aden. Of course, the maps show that the Arabian Sea was not affected by the humidity.The Arabian Peninsula also, due to the high moisture transfer rate, as a transitional route, transmits a large amount of moisture to the study area.Finally, the path of moisture to the study area was mapped and identified, and thus considering the three main conditions for the atmospheric river, it can be said that the path obtained is the same as the atmospheric river.


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