Review mechanism of expansion and low pressure Red Sea

Low Pressure of Red Sea is one of the climates constructing agent in North Africa. Low Pressure of Red Sea has thermal state at the first and then converts to thermodynamic state in the winter. Together with Low Pressure of Red Sea’s deepening trough in the cold period of year, it moves to the west part of the Red Sea and also expands to the Iran .Since the low-pressure check once-place Red Sea in recognition of the activity and rainfall this system plays an important role. So familiar with the features of this low pressure, attention is located. Due to the condition that provision of water is the main source of rainfall, temporal and spatial variation of precipitation was very important in the region and this causes adverse effects especially in the economic activities and livelihood is agriculture. During cold seasons of year with penetration of high pressure tab into Northern part of the Sudan with pour cold weather in media, low pressure in the Sudan invigorates and absorb humid from Red Sea. In fact this frontless system is not active at first. Due to the stretching of this system to Red Sea, it will activate by facing to the air mass of Red Sea. During this research, data sets with high level equal to 1000 (HPA) inducted by NCEP/NCAR with Network breakdown of 2.5  2.5 are used. Due to the use of high according to meter in 1000 HPA, extraction of data sets were done using Grads software and for the extraction of results, MATLAB has been used. Finally, for the purpose of drawing figures, SORFER is used .Based on exploration of data sets, due to the providing humidity, Red Sea’s low pressure is the main source for precipitation in the Southwest of the Iran .also Mean and coefficient of variation maps and statistical mean in 1000 HPA height is calculated. Maximum activity time of this system is determined as November and December. According to our results, intensity and extension of this system are reduced during recent years