上海暴雨涝害和叶菜损失综合评估模型及其应用

从上海夏秋制约蔬菜生产的主要气象灾害暴雨雨涝及影响机制入手，通过对叶菜不同生长期及淹水时间处理的正交逆态试验，建立叶菜淹水损失模型；在菜区主要土壤人工模拟暴雨渗流试验基础上，应用旱地水量平衡原理，通过菜区各地入渗、径流及排涝能力的分析计算，进行淹水程度估算；根据气象条件对叶菜生长动态变化的影响规律，建立叶龄估算式。最后，通过对空间点赋值及数据属性的识别和综合运算，生成雨涝淹水程度及叶菜损失等级统计表和分布图。经１９９７年７月１０～１１日暴雨的模拟验证，取得较好效果。该定量评估方法，为暴雨后快速、直观、客观地提供上海菜区淹水状况分布与叶菜损失率等灾情信息提供了可能。

A MODEL FOR ESTIMATING THE WATERLOGGING DISASTER CAUSED BY RAINSTORM AND LOSS RATES OF LEAF VEGETABLES AFTER INUNDATION AND ITS APPLICATION IN SHANGHAI AREA

According to the influence mechanism of disaster,the extent of waterlogging caused by heavy precipitation is dependent upon the intensities of natural disaster factors(such as rainstorm time length,rainfall value and rain region coverage) and the abilities of bearing and resisting waterlogging disaster(including characteristics of infiltration and water storage of vegetable fields,sewerages of vegetable areas,vegetable varieties and growth periods). Adverse state tests of leaf vegetables at various leaf ages(growth periods) and different inundation times were conducted by a method combining orthogonal design and regression analysis.According to the test results,the regression statistical models of the loss rates of leaf vegetables inundated by waterlogging were set up. The dynamic simulating patterns about the amounts of infiltration and runoff were established based on the data obtained by the artificial simulating precipitation experiments with various precipitation intensities and soil humidities for major kinds of soils in the old and new vegetable areas in Shanghai. Using the principle of water balance,the water amounts of rainfall,infiltration and runoff,and the ability of bearing rainstorm disaster are evaluated,then the inundation time is estimated. Based on the effects of meteorological conditions on leaf vegetables growth,the dynamic prediction model of leaf ages is established.Finally,by giving the attribution values of space grids and identifying the property of data and synthetical calculation,the statistical tables and distribution charts about inundation time and loss rates of leaf vegetables inundated after rainstorm are generated. This assessment method could provide the reliable and quantitative information about the situation of waterlogging caused by rainstorm and loss rates of leaf vegetables rapidly and objectively.It has been used in the simulation of heavy precipitation in the summer of 1997 and acquired good effects.