基于信息熵的淮河流域降水时空变异特征研究

Entropy-based Investigation on Variability of Precipitation in Huaihe River Basin

为了深入研究淮河流域的降水时空变化特征,以淮河流域1961～2005年36个气象站日降水数据为基础,基于信息熵理论,首先利用边际熵研究年、季、月等不同尺度下降水的变化特征;再利用分配熵和强度熵研究年内不同月份降水的分配情况;然后利用改进的Mann-Kendall趋势检验方法对淮河流域降水序列不确定性的变化趋势进行检验;最后对降水月份分配情况与极端降水量进行相关分析,以研究极端降水量与降水月份分配的关系。结果表明,淮河流域降水量较小的季节或地区,其降水量的年际变化也较大,淮河流域北部降水的不均匀性及其较小的降水量可能加剧该区的干旱风险;降水量与降水天数月份分配的不均匀性均表现出由南向北增大的空间分布特征;对于淮河流域大部分站点,降水量月分配不均匀的年份面临洪灾的风险也会增加,而淮河流域西部降水月份分配不均的情况可能加剧,且该区面临的洪灾风险也可能加剧。

The spatial and temporal variability of precipitation in Huaihe River Basin was investigated based on the data of 36 meteorological stations during 1961-2005 and the theory of entropy.The marginal entropy was used to analyze the variability of precipitation series in the scale of annual,seasonal and monthly.Then apportionment entropy and intensity entropy were used to investigate the variability of precipitation within a year.At the same time uncertainty variation trends of precipitation were analyzed by using the modified Mann-Kendall trend test method.Finally,the correlation between the extreme precipitation amount and the variability of precipitation within a year was discussed.The results indicated that high variability of precipitation series was detected in seasons or regions which has less precipitation.Less precipitation and higher variability in the northern part of the basin may increase the risk of drought.The intra-annual variability of precipitation increased from south to north of Huaihe River Basin.The intra-annual variability of precipitation may increase the risk of flood for most of the stations in Huaihe River Basin.The western part of the basin is dominated by enhanced variability of precipitation and it may face a higher risk of flood.