江苏四类低温事件致灾因子与基于影响的低温风险时空分布对比研究

Differences in spatiotemporal variation and risk zoning of four types of extreme cold events in Jiangsu province

  • 摘要: 利用1961—2020年江苏省70个气象观测站数据,分析了4类低温事件(寒潮、霜冻、低温阴雨寡照和冰冻)的时、空分布特征,建立4类低温灾害危险性评估指标和综合危险性指标,结合人口、经济(GDP)两类承灾体的暴露度和脆弱性指数,建立了低温灾害风险评估模型,评估了江苏省低温灾害影响人口和GDP的风险等级及其空间分布。结果表明:(1)1961—2020年江苏省寒潮、霜冻和低温阴雨寡照事件发生较多,冰冻事件发生较少;研究时段内4种低温事件发生日数呈交替出现或多灾种同期多发的特征,1961—1980年寒潮和霜冻事件发生日均较多,2001—2020年低温阴雨寡照和冰冻事件同期多发。(2)江苏省中、南部寒潮频次较多,年平均累计降温幅度较大;霜冻日数北多南少,极端最低气温北部明显较低;低温阴雨寡照日数从西南到东北递减,南部降水偏多,北部过程平均温度较低;江苏西北、西南地区冰冻日数均较多,与降水空间分布一致。(3)江苏北部为寒潮和霜冻灾害高危险区,霜冻危险性呈纬向带状分布,低温阴雨寡照高危险区域集中在西南部;冰冻高危险区在南部和北部均有出现。低温综合危险性在北部和西南部较高,中部和东南部较低。(4)低温对人口和GDP的风险等级具有空间差异,由于承灾体的空间非连续性打破了气象条件的连续性分布,导致低温灾害对不同承灾体所产生的可能风险在空间分布上产生差异。

     

    Abstract: Based on observations collected at 70 stations in Jiangsu province from 1961 to 2020, spatial and temporal variations of four types of cold events are investigated first. A total of 14 evaluation indicators related to cold damages are selected to build the dangerousness index. Using the population and GDP data, the dangerous level and risk-zoning of cold events are then assessed. The results are as follows: (1) Cold air outbreaks, frost events and cold-rainy events frequently occur in Jiangsu province during 1961—2020, while the frozen events have a small total number of occurrence days. Cold air outbreaks and frost events have the maximum number of occurrence days during 1961—1980, while cold-rainy events and frozen events reach the maximum occurrence in 2001—2020. (2) Cold air outbreaks occur frequently in central and southern Jiangsu province during 1961—2020. Correspondingly, frost events occur more frequently over the northern areas than over the southern part of Jiangsu province. The number of days with cold-rainy events shows a decreasing tendency from southwest to northeast of Jiangsu province. Frozen events frequently occur in the southwest and northwest of Jiangsu province, where frozen events have a spatial distribution similar to that of precipitation. (3) High level of danger for cold air outbreak and frost events is located in the north of Jiangsu province, while the high level of danger for cold-rainy events is found in the southwestern areas of Jiangsu province. The high level of danger for frozen events appears in both south and north of Jiangsu province. The composite dangerousness of the four types of cold events shows that the high level of danger is located in the north and southwest of Jiangsu province and the low level appears in central and southeastern areas. (4) There exist notable differences in the spatial distribution and area of high risk between the population and GDP, which are mainly resulted from the spatially discontinuous hazard-bearing body under the condition of a similar meteorological environment in Jiangsu province.

     

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