Variation in the Number of Days with Heavy Precipitation on the Territory of Russia for the Period of 1936-2000

摘要

Time variations in the number of days with heavy precipitation based on data of 93 stations on the territory of Russia are analyzed. Time series of precipitation, corrected by the elimination of main systematic errors of their measurement at the level of their diurnal sums, are used, when computing. The diurnal precipitation sum, exceeding the average long-term diurnal precipitation maximum by three times, was taken as the threshold quantitative criterion, defining "the day with heavy precipitation" concept. This value varies within 10-15 mm/day on the territory of Russia. Extremums fluctuate from 5 to 40 mm/day. Absolute values of linear trends of the annual number of days with heavy precipitation are comparatively small, they fluctuate within ±4 days on the whole territory of Russia. In relative terms, these variations are rather significant, reaching ±40% and more of the corresponding average value for 65 years. The comparison of the spatial distribution of characteristics of linear trends of the annual number of days with heavy precipitation and annual precipitation sum indicates their close conformity.