1961—2010年东北地区降水事件时空均匀性研究

Spatial and temporal homogeneity of precipitation events from 1961 to 2010 in northeast China

利用1961—2010年中国东北三省和内蒙古四盟90个气象站逐日降水资料,分析了东北地区降水事件的气候特征及时空分布均匀性变化。结果表明:近50 a来,东北地区年降水量略有减少,但冬、春季降水量显著增加;考虑降水日数,冬、春季降水量增加主要由于降水强度的增加,夏、秋季降水量减少主要由于降水频次的减少。气候变暖的大背景下,虽然年降水量线性变化趋势并不明显,但降水量年际间分布不均匀性增加,降水有向极端化发展的趋势,夏、秋季表现更为明显,各等级降水事件尤其是降雪在近20 a时间分布明显不均匀。降水量空间均匀性在1993年发生转折突变,突变后空间不均匀性增加,降水日数空间均匀性在1986年发生变率突变,突变后振荡加剧。降水事件时空不均匀性的增加一定程度上造成了东北地区旱涝事件发生的可能性增加,不同地域旱涝事件同发现象加剧。

Based on the daily precipitation data from 90 weather stations in the northeast China during 1961-2010, the climatic characteristics of precipitation events and its temporal and spatial homogeneity were analyzed.The results indicate that the annual precipitation is in a slightly decreasing trend,while winter and spring precipitation in-creases significantly.The increase of precipitation in spring and winter is mainly associated with the increase of precipitation intensity,while the decrease of precipitation in summer and autumn is with the decrease of precipitati-on frequency in terms of the number of precipitating days.Although a linear trend of annual precipitation is not sig-nificant,the inhomogeneity of the inter-annual precipitation increases.There is a trend that precipitation tendency is moving towards extreme direction,especially in summer and autumn.The inter-annual precipitation events in vari-ous grades are inhomogeneous,especially for snowfall events in the last 20 years.The spatial homogeneity of annual precipitation shows an abrupt change in 1993,while that of annual precipitation days is in 1986.After the abrupt change,the spatial inhomogeneity of the former increases and homogeneity of the latter fluctuates significantly.The variation of precipitation events is likely to increase the risks of flood and drought in the northeast China,so is the events that flood in some regions and drought in other regions occur simultaneously.