淮河流域旱涝灾害致灾气候阈值

On threshold of drought and flood disasters in Huaihe River basin

采用淮河流域内1959—2008年110个气象站的逐日降水资料,结合流域1978—2008年农作物旱涝灾害受灾面积数据,基于降水致灾因子与农作物承灾体受损程度等研究,提出旱、涝致灾气候阈值概念,在此基础上分析旱涝灾害发生的时空特征,确定淮河流域合理的旱涝致灾气候阈值区间并建立致灾气候阈值与农作物受灾面积之间的定量关系。结果表明:①致灾气候阈值可通过计算发生旱涝事件时间段累积降水量除以1959—2008年相应时段累积降水量的平均值来定义,得到的旱、涝致灾气候阈值在不同尺度下对旱、涝灾害事件均有较好地稳定反映,可满足研究区旱、涝事件分析需求;②洪涝致灾气候阈值与农作物受灾面积存在一致的变化趋势,而干旱致灾气候阈值与农作物受灾面积相关系数高达0.96,构建了基于干旱致灾气候阈值的农作物受灾面积预测模型。

Based on the daily precipitation from 110 stations in the Huaihe River Basin during 1959--2008, the crop damage area due to drought and flood disasters from 1978 to 2008, the hazard factor from precipitation, the extent of damage for crops, and the spatial-temporal characteristics of disasters are analyzed. The thresholds of drought and flood disasters are calculated and the relationships between the thresholds of drought and flood disasters and the crop damage area are established. The result shows that first, the thresholds of drought and flood disasters can be calculated using the ratio of the cumulative event precipitation to the mean cumulative precipitation of 1959--2008. The ratio can well reflect the severity of flood and drought disasters of varying degrees, and can meet the requirements for analyzing flood and drought events in the study area. Second, the drought and flood disasters quantified by the calculated thresh- olds can reflect all degrees of drought and flood disasters and the affected areas. The thresholds and the affected areas have similar variation tendency. In particular, the threshold of drought disaster and the crop damage area are highly correlated as revealed by the high value of correlation coefficient （0.96）. Thus, a model for forecasting the crop dam- age area is developed based on the threshold of drought disaster.