气候变暖背景下1961—2010年宁夏旱涝灾害空间分布特征和变化规律

利用宁夏20个气象站1961—2010年实测气象资料,采用线性趋势分析、Mann-Kendall非参数检验、标准化降水指数等数理分析方法,对宁夏近50年旱涝灾害时空变化特征进行分析。结果表明:①1961—2010年宁夏气候暖干化趋势明显,增温速率为0.38 ℃/10a,远高于全国和西北地区;②1961—2010年宁夏降水量波动减少且具有整体性,雨量带明显南移,干旱、半干旱区域逐年扩大。③1961—2010年宁夏旱涝灾害交替发生,干旱化趋势明显。④在旱灾方面,宁夏南部山区旱灾频率相对较低,从南向北旱灾频率逐渐上升。北部灌溉区以轻微干旱为主,严重干旱和极端干旱主要发生在中部干旱区。⑤在涝灾方面,宁夏南部山区涝灾相对较少,依然呈现由南向北涝灾频率逐渐上升的空间格局。中等以上涝灾南部山区相对较多,严重湿润和极端湿润主要发生在北部引黄灌溉区。

Spatial-temporal Characteristics of Drought and Flood Disasters under the Background of Global Warming in Ningxia in 1961-2010

In order to monitor the drought and flood disasters variation in Ningxia, based on climate data from 1961 to 2010, we analyzed the fundamental characteristics and temporal-spatial distribution of the drought and flood disasters using methods of linear regression, Mann-Kendall test, and SPI index. Results showed that the trend of warming-drying was significant in Ningxia from 1961 to 2010 with a linear tendency 0.38℃/10a, which was bigger than linear tendency in the whole North-western China and the whole China. The precipitation decreased in Ningxia from 1961 to 2010, the rainfall belt significantly shifted to the south, and the scope of arid and semi-arid area increased markedly. The frequency of the drought and flood disasters was high, and the arid tendency was significant. In Ningxia, the frequency of drought disaster was relatively low in the southern mountain area, and the frequency increased from north to south. The north Yellow River irrigation region suffered mainly from moderate droughts, while severe and extreme drought occurred mostly in middle arid area. The frequency of flood disaster also relatively low in the southern mountain area, and the frequency increased from north to south too. There was relatively high frequency of moderate flood disasters in the southern mountain area, and severe and extreme flood occurred mostly in the north Yellow River irrigation region.