Geographical Research

Variation of climatic elements could be estimated by standard deviation، coefficients of variation and so on. In Iranian climatological literature، variations of climatic elements have main attention during last decades. Meanwhile worldwide climatologist desired to study the characteristics of variations as well as the distribution of frequency average of these elements. In this paper، a useful pattern is presented for studying the variation characters and its trend، absolute and relative variation characters and frequency distribution of daily precipitation of Zanjan city have been analyzed for statistical period of 1961-2006. However there is significant relation between the precipitation and its characters، in spite of a limited variation in the amount of raining، but the character of frequency distribution of precipitation is not decreased. This means that every day have significant decreasing trend. Therefore، in total studying of the precipitation there is no significant variation