تحليل انماط الارتفاعات الجهدية الفصلية فوق الشرق الاوسط باستخدام بيانات ECMWF

Abstract

The geopotential height has a wide effects on air motion in the Atmosphere , and it is considered as the main factor for the general circulation model (GCM) . this variable has multiple relationship with other meteorological variables that it is very important in forecasting way . The methodology proposed and adopted in this work is based on one seasonal ensemble model which is the (ERA-15) model from (European Centre for Medium Range Weather Forecasting) (ECMWF) , and the given data is extended for (14) years was (1979 / 1992) for the Middle East region and two levels (500 hPa) (700 hPa) . The data transformed to integrated seasonal ensemble in order to show the effect of seasonal change . The result showed on analysis of geopotential height for each season for the two levels of the study that there is region with relatively fixed geopotential height values on summer like Saudi Arabia and Arabian Peninsula in about (58000) (m/s)2 while we find this behavior is minimum on winter seasons , and the results show that the geopotential height value reaches its maximum in the south of middle east in about (57600) (m/s)2 while it reaches its minimum value in north of this location in about (54200) (m/s)2 . and the gradient of line in (700 hPa) level always greater as compared with the gradient of line in (500 hPa) level .