台风“利奇马”灾害风险及气象服务效益评估

STUDY ON DISASTER RISK OF TYPHOON LEKIMA AND BENEFIT OF CORRESPONDING METEOROLOGICAL SERVICE

利用气象资料、灾情资料、浙江宁波地方经济发展数据,采用模糊算法、层次分析法等对台风“利奇马”在宁波地区的影响进行风险和灾情评估,“利奇马”灾害风险评估等级是1级、特重,实际灾损虽是50.19亿元,但灾情等级5级、较轻,实际灾损低于风险评估等级;用逆推算法计算宁波地区“利奇马”台风的气象服务效益达41.76亿元,占台风直接经济损失与气象服务效益之和的45%,服务效益显著。政府及水利部门根据气象预报做出关闸滞洪的决策部署,在保障水库和下游河道堤防安全前提下,为城乡积涝赢得了45小时的排水时间,降低平原河网水位的压力,减轻了内涝灾害;同时充足的水库蓄水,使得后期出现气象干旱时,保障了本地供水安全,气象服务在减少内涝等灾害风险和保障水库蓄水等方面发挥巨大作用。

Based on meteorological data,data of losses from typhoon and economic development data of Ningbo,the present study evaluated the effects of Typhoon Lekima on Ningbo by using fuzzy algorithm and analytic hierarchy process(AHP).The result showed that the disaster Risk Assessment Index(I_(ra))of Typhoon Lekima reached Grade 1(extremely heavy).Although the direct economic loss reached 5.019billion,the Actual Disaster Index(I_(ad))was Grade 5(relatively light).The I_(ad) was lower than the I_(ra) because the improvement of disaster prevention capabilities reduced typhoon disaster losses effectively.Based on inverse projection algorithm,benefits of corresponding meteorological service in Ningbo were estimated to be 4.176 billion,which accounted for 45 percent of the sum of direct economic losses and meteorological service benefits.Based on the forecast released by local meteorological service,local government including the water resources department made decisions of closing sluice gates and flood detention.The decisions ensured reservoirs and downstream channel embankments were safe and reduced the risk of water conservancy facilities being damaged.The decisions also won 45 hours of water drainage time for urban and rural waterlogging,which reduced the water level in the river network and mitigated waterlogging disasters.Abundant water storage in reservoirs secured local water supply when there was a meteorological drought.The fine meteorological service played an important role in reducing the risks of waterlogging and increasing the water storage of reservoirs.