近44a宁夏严重干燥事件对气候变暖的响应

Response of Severe Drought Events in Ningxia to Climate Change during Recent 44 Years

利用1961—2004年宁夏20个测站逐日降水资料,分析近44 a来不同时间尺度严重干燥事件对气候变暖的响应特征。结果表明:宁夏发生严重干燥事件的频次高,持续时间长,自北向南逐渐减少。冬季出现频次远高于其他季节,跨季节出现最多的是秋冬两季和秋冬春三季;在川区春小麦和山区冬小麦生长的农事关键期,严重干燥事件频发对其生长造成严重影响,夏季偶发的严重干燥事件会导致严重的旱灾发生;小波分析表明,严重干燥事件存在8 a左右的振荡周期。在全球气候变暖背景下,发生严重干燥事件的次数明显增多,尤其是n≥90 d的严重干燥事件在20世纪90年代中期明显进入增多阶段,目前正处于高发时段,进一步印证了极端干旱气候事件频发的事实。

Based on the precipitation data from 20 stations over Ningxia during 1961-2004, the severe drought events and its response to the climate change were studied. The results showed that the severe drought events occurred frequently, lasted long and reduced from south to north. The severe drought events appeared more in winter than in other seasons, lasted mostly two seasons from autumn to winter or three seasons from autumn to winter till the next spring. In the key period of wheat growing, severe drought e- vents bring out serious loss. The wavelet analysis indicted that the 8-year scale periodicity of the severe drought events was apparent. With global climate warming, the frequencies of severe drought events increased clearly, especially the very severe event with duration n ≥90 days obviously increased since the middle 1990s, with high frequency at present.