تحلیل روند تغییرات بارش برف و باران در ایستگاه‌های منتخب استان آذربایجان غربی

Precipitation as one of the important elements of each region is that it has a considerable impact water sources. The meantime snowfall in the water supply area, particularly in mountainous areas and areas without rainfall in summer is very effective. West Azerbaijan as one of mountainous provinces and lacked the summer rains are that an important part of their precipitation in the form of snow received that in recent years with the drought and the drying up of Lake Urmia has faced. In this research uses data SCDATA related to 7 synoptic stations with different time periods between 1951 to 2012 and with provincial distribution, the first snow and rain data separate and then based on the of computational and sequential Mann-Kendall(MK) and Sen.’s estimator index and the cumulative sum test were analyzed. The results show upward trend snowfall percent in the southern regions of the province and the general trend of decreasing precipitation in northern stations have occurred since 2000. While in majority of the stations, Snowfall has started downtrend from1994. In between stations, Khoy the highest qualitative and quantitative changes and Piranshahr has been no significant change. However, major changes are sudden rainfall in the Khoy and Urmia stations.