长江中下游油菜春季湿渍害灾损风险评估研究

在前期工作基础上,借鉴冬小麦湿渍害判别指数的构建方法,选取降雨量、日照和作物需水量作为油菜湿渍害气象判别指数的构建因子,结合油菜春季湿渍害的产量实际损失,分别从受灾频率、历年受灾站数等角度分析了油菜湿渍害发生的时空分布特征,通过对各气候区平均湿渍害灾年、因灾减产年及各等级减产年的统计,并对比成灾频率和受灾频率,对研究区油菜春季湿渍害进行成灾分析;依据不同等级的减产强度及其发生概率得到油菜湿渍害产量损失风险强度,基于减产频率和产量灾损风险强度最终建立风险评估模型,并依据风险值大小进行分区,同时,为更好地掌握油菜湿渍害在1961—2010年变化情况,分别计算了各地1961—1990、1971—2000及1981—2010年三个时段的风险评估值,以探寻各时段风险区的变化。结果表明:随着时间的推移,研究区内风险高值区范围不断缩小;综合50年的情况看,风险高值区主要位于安徽的江淮西部及江南大部、鄂东南及苏南的局部地区,占全区台站37%;风险中值区的覆盖范围最大,约55%,主要包括安徽东部、江苏的淮北西部、江淮之间、苏南西部及东北部、湖北大部(除了鄂东南、鄂西南的西南角);风险低值区范围最小,约8%,主要分布在鄂北局部和江苏淮北东部地区。

Risk Assessment Study on Rapeseed Suffering from Spring Wet Damages in the Middle and Lower Reaches of Yangtze River

Based on the previous work and drawing lessons from the method of constructing winter wheat wet damage discriminate index,a wet damage weather index was constructed with rainfall,sunshine hour and crop water requirement.Combining with the actual rapeseed yield loss caused by spring wet damage,the spatial and temporal distribution characteristics of rapeseed wet damage were analyzed by wet damage frequency and stations number over the years.According to the statistics of wet damage information such as station number of afflicted year,yield reduction year at different level in every climatic regions and contrasting afflicted frequency with disaster forming frequency,disaster forming mechanism of rape spring wet damage was analyzed.In accordance with yield reduction intensity and occurrence probability at different levels,rapeseed wet damage risk intensity was calculated.Then a damage intensity risk index model was established based on the frequency of yield reduction and damage risk intensity,and zones were divided according to the risk value.In order to understand the changing situation of rapeseed wet damage during 19612010,damage intensity risk indexes were calculated during 19611990,19712000 and 19812010.The results show that high risk areas were continuously dwindling.Synthesizing the damage intensity risk index during 19612010,the results indicate that the western area of Yangtze Huai river valley,the southern region of Yangtze river,the southeast Hubei and parts of southern Jiangsu are the high risk areas of spring wet damages,accounts for about 37% of district stations.The middle risk zones are comprised of eastern Anhui,western part of northern Huaihe,Yangzi Huai river valley in Jiangsu,western and northeastern in southern Jiangsu,and most areas of Hubei which accounts for about 55%.The low risk area accounts for about 8% of the whole district,mainly distributes in parts of northern Hubei and eastern Huaibei areas in Jiangsu.