西北地区东部旱涝气候特征

利用中国气象科学研究院收集、整理的西北地区东部代表站1470~2003年的旱涝等级资料,根据不同的地形地貌特征和气候特征,将西北地区东部分为3个气候区,利用周期分析、coif3小波变换等统计分析方法对3个气候区534年旱涝指数的年代际气候特征及地域之间旱涝变化的差异进行分析。结果表明,西北地区东部不同区域旱涝的时空分布特征不尽相同,旱涝演变趋势、旱涝周期变化既有一致性,也存在明显的差异。534年以来北部、中部由偏旱趋于正常或偏涝,南部1724年以前的变化趋势由偏旱趋于偏涝,1724年以后由偏涝趋于偏旱;3个气候区都存在25年和10年的显著周期,其中中部还存在14~15年的显著周期,说明中部旱涝交替较北部和南部明显。

Drought/Flood Climatic Features over Eastern Northwest China

Using the drought/flood data from representative stations over the eastern Northwest China from 1470 to 2003 collected by the Chinese Academy of Meteorological Sciences,according to different features of terrain,physiognomy and climate,the eastern Northwest China is divided into three climatic regions.By means of statistic methods such as periodic analysis and coif3 wavelet transform,an analysis is made of the decadal variation of drought/flood index in three climatic regions and the difference among them.Results indicate that the spatial and temporal distribution features of drought/flood in three regions are different,and the variation trend and periods not only show consistency,but also exist obvious difference.The drought climate tended gradually to be normal or became wet in the north and the central parts of the area in past 534 years.From 1470 to 1724,the drought climate in the south part tended to be wet.However,after 1724,the wet climate became dry(again.) There are notable periods of 25 and 10 years in drought/flood in the three regions,respectively.In addition,there are obvious periods of 14 to 15 years in the central part.It is illustrated that the alternation of droughts and floodd is more distinct in the central part than those in the north and south parts.