![]() It should be mentioned that to determine the advection of moisture, vertical profile of moisture advection (1000–250 hPa levels) was analyzed. Also level of 1000 hPa was investigated to determine the atmospheric convergence in near surface levels. Pressure levels of 500 and 700 were analyzed to detect the location of troughs, vorticity and vertical wind velocity. The selected indices in this research are relative vorticity, convergence and divergence, vorticity advection, specific humidity and moisture advection. 11 severe torrents which happened in southwest of Iran (1998–2008) are selected and using Japanese ReAnalysis data (JRA25), anomalies of dynamic and thermodynamic indices 2 days prior to the start of heavy rainfalls and during rainy days have been analyzed. In all these synoptic–dynamic systems, low-pressure isobars or low isoheights are considerable. These systems when combined with Mediterranean troughs in cold seasons, and absorbing more humidity from the Red Sea, reach the south west of Iran and result in heavy rainfalls in western, southwestern and southern parts of Iran. Ystems which originate from the Red Sea and their low-pressure isoheights are detectable around south of the Red Sea, Sudan and Ethiopia. Sudanese systems are low-pressure thermal s Thus, further studies and determining some useful indices can be necessary tools for prediction. The results show that the meteorological parameters change during precipitation in the Northwest of Iran due to the Black Sea cyclogenesis. Some synoptical and dynamical parameters attain in this point, such as the mean sea level pressure and its anomaly, 500-hpa geopotential height anomaly, relative vorticity advection, thermal vorticity advection and thickness advection. To compare calculated parameters in the selected systems and recognize their differences, OROOMIEH Synoptic station with 37.32° N and 45.05° E are selected which is called the representative point. In this study, we use a reanalysis dataset produced by the US National Centers for Environmental Prediction (NCEP) and the US National Centers for Atmospheric Research (NCAR). This selection was based on different months, heavy and light precipitation. To investigate the role of precipitation on the Black Sea and the North West of Iran and how the weather parameters change, several cyclogenesis case were selected on the Black Sea. Western and eastern of the Black Sea coasts due to the sea-land contrast and low level baroclinicity provide an opportunity for cyclogenesis. If calculated from Numerical Weather Prediction outputs, then the CEI would be independent of uncertain Quantitative Precipitation Forecasting and could support risk management decisions. Independent re-analyzed data confirmed that high values of the CEI were always associated with heavy precipitation events however, such events were not always accompanied by high values of the CEI. Afterwards, we linearly combined individual predictors and created the Circulation Extremity Index (CEI). Using the ERA-40 database, anomalies in the meteorological fields that have repeatedly occurred during historic heavy precipitation events in the Czech Republic were detected. We demonstrate that the causal circulation conditions can be characterized by combinations of anomalies of properly selected meteorological variables. To account for the variability of the synoptic conditions leading to heavy precipitation, reference events were divided into four synoptic variants. Heavy regional precipitation events are frequently associated with certain circulation conditions in central Europe. This assessment is done by comparing more than one year of continuous profilers observations during different weather conditions with balloon radiosoundings, in-situ aircraft or boundary-layer pressurized balloons measurements. The objective of this paper is to establish to what extent the 3D wind fields derived from the coastline profiler network are representative of the offshore kinematics. They are used to retrieve the 3D atmospheric wind fields over the basin, by assuming linearity of the fields inside a limited spatial and temporal domain. Five UHF profilers for the lower atmosphere description were deployed along the French Mediterranean coast and Corsica Island. The inland three VHF profilers aimed to document the upstream or downstream synoptic flow conditions. These profilers provided vertical profiles of wind vector, turbulence, precipitations, and the height of the atmospheric boundary-layer and tropopause. Eleven UHF and VHF wind profiler radars were in operation for 13 to 18 months during the international HyMeX field campaign devoted to the study of the atmospheric and marine water cycle in the western Mediterranean basin.
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