白龙江流域极端降水年际变化及对气候变化的响应

Interannual Variation of Extreme Precipitation and Response to Climate Change in Bailongjiang Basin

受极端降水的影响,白龙江流域极易发生地质灾害,严重威胁当地的经济发展与生命安全。为此,根据白龙江流域1965~2011年5个气象站点的逐日降水资料,计算极端降水指数,采用Mann-Kendall检验法分析白龙江流域极端降水的年际变化特征及对气候变化的响应。结果表明,1970年代初期到1980年代中期白龙江流域极端降水指数均显著增加,1990年代中期之后显著减少,其中大雨日数发生了减少突变;各站点强降水次数变化特征差异显著,强降水次数的线性拟合减少率为0.002~0.280次/10a,迭部和武都长期减少趋势最明显,文县和武都发生了减少突变;极端降水指数与年平均气温呈显著负相关,相关系数为-0.46^-0.36(P<0.05),与年平均降水量呈显著正相关,相关系数为0.77~0.82(P<0.01)。

Being affected by extreme precipitation, it＇s easily to take place geological hazard in Bailongjiang basin and posed a serious threat to the local economic development and safety of life. Based on the daily precipitation data of 5 mete- orological stations from 1965 to 2011 in Bailongjiang basin, extreme precipitation indices were calculated. And then the interannual variation characteristics of extreme precipitation and response to climate change were studied with Mann-Ken- dall method. The results indicated that the extreme precipitation indices were significantly increased in the early 70s to the mid-80s while decreased significantly after the mid-90s, among which the heavy rain days occurred abrupt change of re- duction; the trend change of torrential rainfall days appeared remarkable difference; the tendency rates were in the range of 0. 002 to 0.28d· a-l. Long-term downward trend of Diebu and Wudu regions were obvious; Wenxian and Wudu re- gions occurred abrupt change of reduction. According to the correlation analysis, there was an obvious negative correla- tion between mean annual temperature and extreme precipitation indices, and the correlation coefficient was between -0. 36 and -0.46 （P〈0.05） ; while the correlation between mean annual rainfall and extreme precipitation indices was positive the correlation coefficient was in the range of 0.77 to 0.82 （P〈0.01）.