南盘江流域季节性干旱时空分布特征研究

Temporal and spatial distribution characteristics of seasonal drought in Nanpan River Basin

为了有效减少干旱损失,以及为合理预测干旱提供依据,对南盘江流域干旱的发生规律和形成成因进行了研究。选取流域范围内25个气象站40 a(1971～2010年)的逐月降水和气温资料,计算RDI干旱指标,统计近40年来各站点发生干旱次数,以每个站点当年11月至次年5个月时间尺度的RDI多年平均值为指标,进行空间插值,并结合降水和气温分布分析南盘江流域季节性干旱时空分布特征。认为:流域季节性干旱加剧;各个地区都会发生不同程度的气象干旱;RDI指数的较小值区域与降水较少、气温较高的区域基本吻合,中部大部分地区、南部和东北部的部分地区干旱较严重。

In order to reduce the loss caused by drought, we studied the laws of drought occurrence and its causes so as to provide basis for drought prediction. By choosing the monthly precipitation and atmospheric temperature data of 40 years （1971 - 2010） from 25 sites in Nanpan River Basin, the reconnaissance drought index （RDI） is calculated. We count the times of drought occurrence of each site in 40 years. Taking November to next March as the research period, the average RDI in multi - years are calculated and the spatial interpolation is conducted as well. Combining with precipitation and atmospheric temperature data, the temporal and spatial distribution characteristics of seasonal droughts of Nanpan River Basin are analyzed. The results show that the seasonal drought becomes more serious; the meteorological drought of different degrees will occur in all regions of Nanpan River Basin; the area where the precipitation is less and temperature is higher has small RDI as well. The drought in the most parts of central region and some parts of southern and northeast region is more serious.