Variability in the Duration of Rains and Other Elements of the RainCourse

Abstract

Rains of varying intensity and duration have different effects on the water balance of territories and economic indicators of regional development. The paper examines the features of changes in time and in various physical and geographical conditions of the duration of rains and the position of the maximum intensity during rain. It is shown that in mountainous areas there is more precipitation, both in quantity and frequency.The research used methods of mathematical statistics and graphical analysis.In general, for all four meteorological stations, which were studied, a similar distribution of the probability of occurrence of rains with a given duration is characteristic. Rains lasting more than 400-500 minutes occur in less than 10% of all meteorological stations. For rains lasting less than 300 minutes, there is a difference in the probability of occurrence of 5-10% between meteorological stations. Some limits of air humidity, air temperature and soil surface at which rain was not observed are determined, what is important when forecasting. Analysis of the influence of meteorological parameters on the duration of rains and the position of the maximum intensity during rain shows that at an average relative humidity of less than 45-50 percent there was practically no rain, and at a minimum relative humidity of less 30% as well. Air temperature (average, maximum and
minimum) of 20-25 °C is critical, above which rains lasting more than 400-500 minutes did not occur. The longest rains are observed at low average daily air temperatures, less than 10 °C. At a minimum soil temperature of 20 °C and above, rains are practically not observed (4 cases out of 989). At an absolute maximum soil surface temperature of more than 50 °C, prolonged rains of more than 500 minutes are also practically not observed.