Snowfall and Its Relation to Temperature over Kurdistan Province

In order to determine the snowfall threshold temperature in different regions of Kurdistan province, first the occurrence times of the non shower snow, associated with dry-bulb temperature and dew point temperature at the time of observation were extracted for 7 synoptic stations of the province. Then, the frequency, relative frequency and cumulative frequency of snowfall in different temperature ranges were recognized for each station. Throughout frequency analysis, the normal distribution is recognized as the best probability distribution for fitting to temperature data. According to that, the snowfall probability in a certain temperature and less than that was calculated. In order to predict the type of precipitation, the correlation between dew point and deficit during the falling of snow was determined. The results show that the mean temperatures at the snowfall times are negative for most stations. Due to temperature transition from positive phase to negative, the snowfall frequency in 0-0.5°C is more than the other ranges. Snowfall is rare in temperatures greater than 3°C over those stations. Maximum probability of snowfall with positive temperatures is almost %25 for 0.3°C up to1°C.