الهطول الثلجي في العراق

Abstract

Snowfall is defined as an important climatic phenomenon. This paper attempted to shed light on the climatic features and comprehensiveness responsible for its formation in Iraq. And the paper reached to the fact that there are several pressure systems responsible for snow formation in Iraq like low pressure area of Mediterranean especially, in the (west part and its south west part) which is considered to be the most pressure system accompanied by snowfalls at a rate of frequency (40%), it is followed Sudanese low pressure area by (28%) and the integrated low pressure area by (20%), while the rest of snowfall cases are caused by two European high pressure areas at a rate of (8%) and the Siberian one by (4%) which is a small ratio of its formation. The paper also found out that the low pressure areas responsible for snow formation and they are the deep type. Besides, (50%) per cent of snowfall cases contain cold upper canyon within pressure level (500) M-Bar where its height average reached 5600 M specifically the east of the canyon whereas, the other (50%) of snowfall is accompanied by cold upper low pressure area in the east. As for the weather condition accompanied by snow in Iraq, most of snowfall cases take place in Iraq when the temperature of air surface is above zero centigrade with by several degrees. It is very rare to see air pressure less than (1007) M-Bar. It is found that the low pressures areas that come to Iraq are of pressure value less than (1007) M-Bar and it is rare to be accompanied by snowfalls. Moreover, wind speed is either slow or motionless as a result of the nature of the cold and heavy air of the pole. Furthermore, the wind movement is variable during the period of snowfall in Iraq and this is caused by several systems of snow formation. However, the highest rate of frequency was from North West direction while relative humidity have reached (100%) in most of the cases.