CHARACTERISTIC OF CONDITIONS OF HEAVY RAINS IN PERM REGION USING ATMOSPHERIC INSTABILITY INDICES

Abstract

Currently, interest to alternative methods of the analysis and forecasting of dangerous meteorological phenomena has considerably increased due to the low density of the observational network, which is insufficient to provide all users with necessary information in a timely and qualitative way. A general analysis of precipitation characteristics for the period from 2004 to 2016 was conducted during the work. The favorable synoptic conditions for heavy rains precipitation have been identified; their dependence on the altitude was discovered. The aim of this research is to analyze the incidence of heavy rains in the Perm region and to assess instability indexes, which are calculated for specific cases of this phenomenon. For this goal, 5 indices (LI, VT, CN, TT, K) were selected. Their values were calculated in terms of heavy rains based on reanalysis data. It was found that the average settings, which were obtained during the calculation, are slightly lower than the values calculated for other regions and given in previously published researches of this field of science. It means that it is necessary to establish specific indices criteria for the Perm region. Developing of convection and heavy rain in Perm region can be expected when the values of instability indices are near to the calculated values, at which at least 90 % of the total number of cases of the studied meteorological phenomenon occurred. A larger sample should be used to calculate the instability indices for analysis and forecast of heavy rains in practice.