黑河流域1967-2009年气象干旱时空变化特征

以标准化降水蒸散指数(SPEI)反映气象干旱,基于黑河流域内外19个气象站1967-2009年月气象数据,计算季节尺度SPEI序列,利用M-K趋势检验、小波分析、反距离权重(IDW)插值等方法分析黑河流域春、夏、秋、冬四季43年间干旱变化趋势、周期特征以及干旱频率的空间分布特征。结果表明:中、上游干旱指数呈增大趋势,即旱情有所减缓,而下游干旱指数呈减小趋势,即干旱情况逐渐加重;无旱频率最大,且从上游到下游整体呈增加趋势;黑河流域干旱周期特征主要表现出16~22a和32~33a的年代际周期及2~5a和6~11a的年际周期特征;黑河流域四个季节轻中旱发生频率比重特旱发生频率大得多,且春、夏和秋季的轻中旱发生的高频区集中在中上游,冬季集中在下游,而四季的重旱和特旱发生高频区空间分布特征与轻旱和中旱正好相反。研究结果可为黑河流域水资源合理开发利用和科学抗旱提供理论依据。

Spatial-temporal variation characteristics of meteorological drought during 1967-2009 in the Heihe River Basin

Using the Standardized Precipitation Evapotranspiration Index (SPEI) to reflect the meteorological drought, and based on the monthly meteorological data of 19 weather stations both inside and outside of Heihe River Basin (HHRB) in 1967-2009, this study calculated the season scale SPEI sequence and analyzed the drought trend, cycling characteristics, and drought frequency spatial distribution characteristics of four seasons during the 43 years using the M - K trend test, wavelet analysis, and inverse distance weighting (IDW) interpolation method. The results showed that: the SPEI showed increasing trend in the upper and middle reaches, whereas expressed decreasing trend in lower reaches. The frequency of drought-free occurrence was the highest, and the frequency decreased from the upstream to downstream. The drought of HHRB had 16-22 and 32-33 years inter-decadal oscillation period and 2-5 and 6-11 years inter-annual oscillation period. The frequency of light and moderate drought in four seasons of HHRB was much greater than that of sever and extreme drought, the high frequency regions of spring, summer and autumn drought were situated in the middle-upper reaches, while that was concentrated in downstream in winter. And the spatial distribution of sever and extreme drought with high frequency was contrary to the light and moderate drought. This study can provide theoretical basis for rational development and utilization of water resources and scientific drought resistance in HHRB.