摘要
利用中国气象台站1961—2006年的逐日观测降水资料,选取百分位数阈值将有效降水分为小雨、中雨、大雨和极端降水,并结合微量降水事件,采用线性回归分析和概率分布拟合的方法,研究了中国降水的时空变化特征。研究表明:1961—2006年中国年降水量在东北地区南部、黄河下游、黄土高原及长江上游这一接近直角分布的地带一致减少,且降水量减少区的范围随着降水强度的增加而缩小;黄土高原和长江上游总降水量的减少与中雨量的显著减少密切相关;长江中下游、东南地区及100°E以西地区降水量一致增加,长江中下游、东南地区总降水量的增加主要由大雨量、极端降水量的增加所造成,100°E以西地区中雨量、大雨量和极端降水量都以增加为主。除新疆西部个别台站外,年总降水频次一致表现为显著的减少趋势;年有效降水频次在西北地区显著增加,而在100°E以东地区一致减少,西部地区的增加由中雨、大雨和极端降水频次的增加共同决定,且中雨频次的贡献最大,东部地区的减少主要表现在小雨和中雨频次显著减少。微量降水事件普遍减少,冬季减少比例最大、夏季减少比例最小,北方地区的减少比例明显大于南方,这与平均气温变化幅度的季节以及空间差异都非常相似。整体而言,中国区域平均的小雨量显著减少,大雨量和极端降水量有所增加;小雨和中雨频次减少,而大雨和极端降水频次增加。
Using daily observations of precipitation for the period 1961-2006 in China, we chose the percentile based thresholds to define precipitation events with different intensities in this study. There is light rain, moderate rain, heavy rain and extreme rain. The characteristics of these effective precipitation events are analyzed in conjunction with trace rain events (<0.1mm/d). During 1961-2006, the annual precipitation decreased in southern Northeast China, the lower valley of the Yellow River, the Loess Plateau, and the upper valley of the Yangtze River, the areas with decreasing trends shrank as precipitation intensity increased, the decreasing of the total precipitation in Loess Plateau and the upper valley of the Yangtze River is closely related to significantly decreasing moderate rain;The annual precipitation generally increased in the middle and lower valleys of the Yangtze River, Southeast China and the area to the west of 100°E, which was mainly induced by the increasing heavy rain and extreme rain in the first two areas, and also by the increasing moderate rain in the third area. The annual total precipitation events generally decreased except at a few stations in Xinjiang;the annual effective precipitation events increased significantly in Northwest China while they generally decreased to the east of 100°E, the frequencies of moderate rain, heavy rain and extreme rain all increased in Northwest China with the largest increase for moderate rain events, while the decrease of light rain and moderate rain events dominated to the east of 100°E. The trace rain events generally decreased. The largest decreasing proportion occurred in winter and the lowest in summer. The decreasing proportion was obviously larger in northern China than in southern China, which is consistent with the distribution of temperature variation in China. For China as a whole, the precipitation significantly decreased for light rain while it increased for heavy rain and extreme rain;the occurrence decreased for light rain and moderat
出处
《气象科技进展》
2013年第3期59-66,共8页
Advances in Meteorological Science and Technology
