海河流域不同降水极值的时空变化分析

Temporal and Spatial Variation Analysis of Different Precipitation Extremes in Haihe River Basin

采用4种日降水情景,分析1961-2010年海河流域降水极值的时空变异性。研究结果表明,海河流域日降水量的平均值呈下降趋势,且随着时间的推移,其波动变弱。从20世纪60年代到2000年代,日降水量的平均值为1.4mm/d,降水的等高线向流域东南部移动了100km以上。4种日降水情景的变化具有很大差异性;天津市和廊坊市是80年代后海河流域的P0干旱中心,无降水的天数和地区数随着年份的增加而增加;P10极值的大小在过去50年中没有明显变化,但是降雨中心随海河流域区域的不同而不同;P20极值的变化幅度在1961-2000年没有明显变化,但在2000年有所增加;在过去50年中,P50极值的变化幅度明显下降,降雨中心从海河流域的东北部向南部移动。城市化的影响反映在80年代和90年代的一些城市,但在2000年之后,由于海河流域的降雨量显著减少,导致其城市化影响表现并不显著。

In this paper, four daily precipitation scenarios are used to analyze the spatio-temporal variability of precipitation extremes in Haihe River Basin from 1961 to 2010. The results show that the average daily precipitation in Haihe River Basin shows a downward trend and its fluctuation becomes weaker with the passage of time. From 1960s to 2000s, the average daily precipitation was 1.4 mm/d, moving more than 100 kilometers to the southeast of the basin. There are great differences in the changes of four daily precipitation scenarios. Tianjin and Langfang are P0 drought centers in Haihe River Basin since 1980s. The number of days and regions without precipitation increases with the increase of years. The magnitude of P10 extremum has not changed significantly in the past 50 years, but the rainfall center varies with the Haihe River Basin region. The variation range of P20 extreme value did not change obviously from 1961 to 2000, but increased in 2000. In the past 50 years, the variation of P50 extreme value has obviously decreased, and the rainfall center has moved from the northeast to the south of Haihe River Basin. The impact of urbanization was reflected in some cities in the 1980s and 1990s, but after 2000, the impact of urbanization was not significant due to the significant reduction of rainfall in the Haihe River Basin.