Statistical procedures application and results of research of precipitation on mountain Stara planina

In this paper, brief review of few statistical procedures, which can be used in climatological researches is given. For some of them, statistical formula is shown. As a numerical example, we have choose mean annual and decadal data for NAO index and amount of precipitation on wider area of mountain Stara planina in period 1951-2000. On a first place, homogeneity of precipitation data from 11 stations which are located on mentioned area is tested by usage of Man-Whitney's test. Fulfillment of lacking data is done with three different methods. By application of different statistical procedures we have try to determine which one of them is the most convenient in explanation of precipitation spatial distribution and connection with NAO index. Application of parametric and nonparametric procedures, shown that there is statistically significant correlation between NAO index and amount of precipitation on both, annual and decadal scale. Relation between amount of precipitation and slope exposition on mountain Stara planina is examined. Linear trend of precipitation is calculated and its statistical significance on a decadal scale in mentioned period is tested