气候变化背景下淮河流域干旱演变特征

Characteristics of Drought Evolution in the Huaihe River Basin Under the Background of Climate Change

[目的]淮河流域是我国主要的粮食生产基地,明晰流域内干旱演变特征及其极端性对科学开展旱灾防御治理具有重要作用。[方法]基于淮河流域1971-2015年降水数据,计算3个月时间尺度的标准化降水指数(SPI),结合反距离权重空间插值法、气候倾向率、游程理论对干旱时空演变特征及其特征变量进行了分析。[结果](1)四季中,春、秋季呈干旱化发展趋势,且秋季速率明显大于春季,夏、冬季呈湿润化趋势,夏季速率大于冬季。(2)全区各季平均干旱频率均在30%左右。空间上,春季流域北部湿润化,南部干旱化;夏季流域北部干旱化,南部湿润化;秋季大部分地区气候倾向率为负值,正值区仅在江苏北部出现;冬季大部分地区呈湿润化趋势。(3)干旱特征变量中,干旱历时与干旱次数的空间分布特征相反;烈度峰值高值区与干旱历时、干旱烈度在流域东北部空间分布较为一致;流域东南部烈度峰值高值区较干旱历时和干旱烈度向东南部略有偏移。[结论]流域内秋季干旱化趋势明显,冬季呈湿润化发展,春夏季干旱演变存在地区差异,区域内干旱呈现极端化发展趋势。

[Objective]The Huaihe River basin is a main grain production base in China.It is important to understand the characteristics and extremes of drought evolution in the basin for scientific drought prevention and control.[Methods]Based on the precipitation data of the Huaihe River Basin from 1971 to 2015,the standardized precipitation index(SPI)of 3-month time scale was calculated,and the spatial and temporal evolution characteristics of drought and its characteristic variables were analyzed by combining the inverse distance weight spatial interpolation method,climatic tendency rate and theory of run.[Results](1)In different seasons,spring and autumn showed a trend of arid development,and the rate of autumn was significantly higher than that of spring.Summer and winter showed a trend of wetting,and the rate of summer was higher than that of winter.(2)The average frequency of drought in all seasons was abou 30%.In terms of spatial distribution,the northern part of the basin was humidified and the southern part was arid in spring,the northern part of the basin was dry and the southern part was humidified in summer,the climatic tendency rate in autumn was negative in most areas,and the positive area only appeared in northern Jiangsu.In winter most areas showed a trend of humidification.(3)Among the drought characteristic variables,the spatial distribution characteristics of drought duration and drought frequency were opposite,the spatial distribution of peak intensity was consistent with drought duration and drought intensity in the northeast of the basin,compared with the drought duration and drought intensity,the high value of the peak intensity in the southeastern part of the basin shifted slightly to the southeast.[Conclusion]There was an obvious trend of dryness in autumn and wetness in winter and regional differences in the evolution of drought in spring and summer,and drought showed an extreme development trend in Huaihe River basin.