Zmienność na obszarze Polski postaci funkcji rozkładu prawdopodobieństwa przepływu maksymalnego w roku

Identification of probability distributions of maximum discharges at fifty cross-sections on Polish rivers is presented in the paper. Three distributions: log-normal, Pearson type III and Gumbel were taken into consideration. Their parameters were estimated by two methods: method of moments and maximum likelihood method. Traditional Kolmogorov-Smirnov goodness-of-fit test did not reject any of the proposed distributions, independently of estimation method. The modified Kolmogorov-Smirnov goodness-of-fit rejected only a few distributions. It appears that it is not much sharper. In this case two-sted selection was assumed. First of all method of moments was accepted, because it is more sensitive (in the range of high values) than the maximum likelihood method. Next that distribution was selected (from among the existing candidates) whose test statistic λ had the least value. The results were illustrated on the map of Poland. It turned out that certain homogeneous areas of distributions appeared. The area of the Vistula river basin except its downstream part is dominated by log-normal distribution while Gamma distribution prevails on the Oder basin and northern part of the country. This conclusion is encouraging, not enough however to be the base of further generalizations and resulting applications. However, it does not give good enough basis for more general conclusions and practical application.