关键词: 新疆, 降水, 时空分布

Abstract:

Daily precipitation data from 1960 to 2001 of 98 weather stations in Xinjiang were used to analyze the differences and spatial distributions of daytime and nighttime precipitation frequencies and intensities in cold season (Oct. to next Mar.) and warm season (Apr. to Sep.). Results show that, in warm season, there were two high nighttime precipitation frequencies areas and two high daytime precipitation frequencies areas where the percentages of nighttime and daytime precipitation frequency respectively were ≥55％. The two nighttime precipitation areas were northern slope areas of Tianshan Mountains and Kunlun Mountains. Two high daytime precipitation areas were southern slopes of Artai Mountains and Tianshan Mountains. But in cold season, the daytime and nighttime precipitation distribution was disappeared. Except for west Tianshan mountains in higher elevation and west Tarim basin and Tu-shan-tuo basin in lower where there were some nighttime precipitation and daytime precipitation respectively, the percentages of daytime and nighttime precipitation in other Xinjiang areas were between 45% and 55%, which were basically equivalent. The differences of daytime and nighttime precipitation became unconspicuous compared with warm season. As for warm season heavy rainfall events (12 hour precipitation >15mm), more than 60％ events occurred in nighttime in Ily valley, middle and east Tianshan Mountains, northern slope areas of Kunlun Mountains, whereas more than 60％ events occurred in daytime in southern slopes of Artai Mountains and Tarbarhtai Mountains, and basin area in northeast Tianshan Mountains. Secular trends in the diurnal cycle of precipitation in warm season showed that the nighttime precipitation increasing rate was little more than the daytime increasing rate in regions with high frequency of nighttime precipitation.

Key words: Xinjiang, precipitation, spatial-temporal distribution