基于标准化降水指数的汉江流域干旱时空分布特征

Drought Temporal and Spatial Distribution of Hanjiang River Basin Based on the Standardized Precipitation Index

随着流域内经济社会快速发展以及南水北调中线一期工程调水,汉江流域水资源需求日益加大,流域管理面临较大挑战。从干旱角度分析汉江流域缺水状况,根据汉江流域13个国家基本气象站44a收集得到的月降水量资料,用标准化降水指数(SPI)作为干旱指标,从干旱频率、干旱站次比、干旱强度以及气象变化趋势率4个方面对汉江流域的干旱时空分布特征和演变规律进行分析。结果表明:年度、春季和秋季干旱站次比呈轻微增加趋势,夏季和冬季干旱站次比呈轻微减小趋势;春季、秋季和冬季干旱强度呈轻微增加趋势,年尺度和夏季干旱强度呈轻微减小趋势;区域内主要发生的是全域性和局域性干旱,干旱强度以轻度干旱和中度干旱为主;春季干旱频率较高的地区主要在流域西部的汉中等地和南部的房县、老河口、天门等地,夏季干旱频率较高的地区主要集中在流域北部的佛坪、尚州、西峡等地,秋季干旱频率较高的地区主要集中在流域南的老河口、枣阳、钟祥等地,冬季干旱频率较高的地区主要集中在流域南部的房县、老河口、枣阳、安康等地。

With the development of economy and society and the completion of the first phase of the middle route of the south-to-north water diversion project in 2014,the water consumption in the river basin increases rapidly.The management of the basin is facing greater challenges nowadays.So it is necessary to study its drought characteristics.Based on the collected monthly rainfall in 13 national basic weather stations,standardized precipitation index（SPI）as a drought index,the time-space distribution of drought is studied and the reason of the time-space distribution is discussed.With year time scale,proportion of drought frequency of spring and autumn station shows a slightly increasing trend,proportion of drought frequency of summer and winter shows a slightly decreasing trend,drought intensity of spring,autumn and winter shows a trend of slight increase,year and summer drought intensity shows a trend of slight decrease.All global drought and local drought are the main droughts in the basin.Mild drought and moderate drought are the main drought intensities.Spring drought is highly-frequent in the western and southern basins.Summer drought is mainly concentrated in the northern river basin,the autumn drought region is mainly concentrated in the southeast basin.Winter drought is mainly concentrated in the southern basin.The research provides a technical support for drought-relief measures in Hanjiang basin.