The Impact of Red Sea Trough on Iran Precipitation

Precipitation is one of the most complicated atmospheric elements having a lot of spatial and temporal variability. Specifying its characteristics and humidity sources, makes it possible to predict and understand this atmospheric element in a better and deeper way. The Red Sea trough is a surface low pressure which is extended over the Red Sea. This trough is usually associated with dry and warm weather. Simultaneous existence of a trough in middle level with surface trough can cause heavy precipitations and showery weather in east of Mediterranean and also in Iran. To verify the effect of the Red Sea trough on the precipitation of Iran, firstly the Iran precipitation data for a specific period (1/1/1340 to 10/10/1383 solar) were prepared. Secondly the Red sea trough for this period was also identified. Cluster analysis of the red sea trough showed that this trough has three main patterns. Then precipitation increment percent for each month of the year for every pattern of the Red sea trough was calculated and their maps were drawn too. This work was done for each day of the year as well.