Modern dynamics in main climate characteristics at sites of North-Western Black Sea coast

Abstract

The aim of the study is to determine statistical estimates for the distributions of average monthly and annual temperatures, as well as monthly and annual precipitation for the North-Western Black Sea coast during the climatic change intensification epoch. Parameters of the normal distribution for temperature, two- and three-parametric gamma distribution for precipitation, as well as trend characteristics, are analyzed. To determine the deviation of the values from the previous climatic period, the data of the Climate Cadastre of Ukraine (1961–1990) were used. The results of the statistical analysis show that steady trend towards an increase in annual air temperatures exists at all stations during the period (2000-2018). In the time course of these characteristics, there is a clearly pronounced separation into two periods with the transition point in 2007. The average monthly air temperatures for the period generally exceed the same values for 1961-1990, and this is especially evident for the summer months. Time distributions of monthly precipitation are spatially heterogeneous. It was found for Odesa that the maxima are observed in January, July and September, in contrast to other stations, at which the maximum amount of precipitation is registered in the summer months. Also, at the Odesa, the monthly precipitation in most months exceeds the same values for 1961-1990. Annual precipitation during 2000-2018 has a lot of regularities and differences, among which, for example, a common feature is the presence of maxima in 2010. In accordance with the general period trend characteristics, a tendency to an increase in the annual precipitation was found in the very south (Izmail station) only, and it has been especially pronounced since 2009. However, their mean values are lesser than in the Climate Cadastre of Ukraine; this is also observed for the stations Lyubashivka and Mykolaiv. On the contrary, at stations located on the coast (Odesa, Ochakiv), the annual precipitation exceeds of values from the Cadastre. Based on the analysis carried out, it can be concluded that all persistent tendencies to changes in the values of the considered climatic characteristics are associated with a possible change in the atmospheric circulation over the considered territory.

Keywords

• average monthly temperature, annual temperature, monthly precipitation, annual precipitation, gamma distribution, excess, asymmetry.