【摘要】 利用黄河流域58个气象站点1961—2005年的逐日平均气温、最高气温、最低气温和逐日降水量数据,采用百分比阈值法定义极端气温和极端强降水事件,计算气象综合干旱指数(CI),并分析了黄河流域极端气候事件的变化趋势及其空间格局。结果表明:黄河流域极端低温和极端高温天数分别呈减少和增加趋势,平均速率分别为-3.8 d/10 a和1.7d/10 a;年极端强降水总量的变化趋势存在着明显的区域差异,河源区增加最显著,而中游的黄土高原中、东部减少最显著;干旱天数呈减少趋势,河源区减幅最大,河套-宁夏平原以及鄂尔多斯高原西北部的减幅最小。更多还原

【Abstract】 The paper defines the events of extreme climate and extreme strong precipitation,calculates the comprehensive meteorological drought index(CI) and analyzes the variation trend and its spatial pattern of extreme climate events happened in the Yellow River basin by using the data of daily average temperature,the maximum and minimum temperature and daily precipitation of 58 weather stations during 1961-2005 period of the basin and using the method of threshold value.The outcomes show that a) the days of the lowest temperature and highest temperature of the basin show the trend of reduction and increase respectively and the average rate is-3.8 d/10a and 1.7 d/10a respectively;b) the variation trend of total extreme strong precipitation has obviously regional difference.The headwater region is remarkable in increase and the center and east parts of the Loess Plateau situated in the middle reaches are remarkable in decrease and;c) the days of drought are in the trend of reduction.The maximum reduction happens in the headwater region and the minimum in Hetao-Ningxia plain and the northwest of Ordos Plateau.更多还原