1-Introduction Iranâ s precipitation mainly affects by air masses that arrive to it from adjacent
area directly or affects as teleconnection pattern due to remoteness from water sources. Due
to irregular arrival of the air masses to Iran and far distance to teleconnection centers,
occurrence of precipitation variations is one of the prominent characteristics of Iranâ s
climate. Also due to short period of instrumental data in the meteorological stations, there is
no possibility for understanding of the climatic variations during the last centuries …