POST-DISASTER SURVEY OF TYPHOON MEGI IN WENZHOU CITY

This paper reports the post-disaster results due to Typhoon Megi. The survey was conducted by a joint survey team of Shanghai Typhoon Institute in 14 December 2016, with the support of Wenzhou Meteorological Bureau and some meteorological departments in disaster areas. The survey results show that Typhoon Megi brought torrential rain and heavy rainstorm to the southern of Wenzhou City. The precipitation characters of Typhoon Megi are strong intensity, high accumulation, long duration and broken historical record. Typhoon winds affected wide,with large peripheral wind. According to the needs of defense and emergency rescue of Typhoon Megi,Wenzhou meteorological departments made every effort, including closely monitor, strengthening consultation, roll forecast, timely warning, active reporting, and targeted service. In order to provide scientific reference for government decision, the service of weather protection and disaster relief were done well. The results of typhoon forecast shows as follows.(1) The track, landing location and time of typhoon forecast were basically consistent with the actual situation.(2) The wind forecast was close to the actual.(3) The forecasted area precipitation was slightly lower, and the extreme value of process precipitation was too low. While the prediction of Dongtou Island Station was too high, this investigation shows that we are still insufficient in forecasting precipitation grades of typhoons breaking historical records, especially for precipitation quantification and meticulous prediction. In this case, more attention should be paid as below. 1) Effect of topography on precipitation enhancement. 2) Summary of similar cases. 3) Improve the defense ability and residents' awareness of risk. 4)Combine modem methods of early warning information with traditional methods. 5) Quantitative, fixed-pointed and precision forecast. 6) Rapid access of referent information to forecasters, 7) Modern monitoring technology(3 S, unmanned aerial vehicle) should be used for disaster investigation, monitor and hidden trouble detection.8) Carry out the renovation of the engineering construction design standards, impact assessment and structure of buildings.

A METHODOLOGICAL STUDY ON AMH COPULA-BASED JOINT EXCEEDANCE PROBABILITIES AND APPLICATIONS FOR ASSESSING TROPICAL CYCLONE IMPACTS AND DISASTER RISKS(PART Ⅰ)

A disaster induced by a tropical cyclone(TC)is a complex non-linear process,involving interactions of multiple factors.Assuming that the resilience to TC disasters remains basically unchanged,the disaster-causing risk is usually consistent with intensities of the TC-induced rainstorms and wind.When an area is hit by a low probability TC,the rainstorm and wind intensities are higher,and the likelihood for causing a disaster is greater.Therefore,criteria for the impact of a TC and disaster risk assessments can be established based on the probable intensities of the TC-associated rainstorms and wind.In this study,an AMH Copula-based function is introduced to investigate the joint risk probabilities of TC rainstorms and wind.In line with the equivalence principle of the distribution of a stochastic atmospheric phenomenon in both time and space,and taking the impact on Shanghai of TC Haikui as an example,the Copula-based joint probability distribution model is developed to assess the impacts of TC rainstorms and wind,based on the marginal distributions of the maximum daily rainfall and extreme gust velocity.The joint exceedance probabilities of TC rainstorms and wind derived from the model can be used as criteria to measure the risk levels.As our findings show,this approach captures the TC risks well,especially in high-risk areas.The aim of the study is to provide a practically useful concept for making more accurate assessments of the risk level of an extreme weather event using observational data,and objective criteria for risk avoidance and transfer.

RECONSTRUCTION OF TROPICAL CYCLONE AFFECTING EAST CHINA DURING 1450-1949 FROM HISTORICAL DOCUMENTS

The natural disaster information in the historical documents in mainland East China are investigated and collected.A set of criteria is set up to discern the tropical cyclone(hereafter TC) influences from these records.The criteria construction is based on the knowledge of TC and TC disasters in instrumental era.Five TC features are considered in the criteria,they are occurring time,spatial scale,lasting time,disaster characteristics and associated weather phenomena.Altogether 1445 affecting TC events are found from historical documents during 1450-1949 in mainland East China.The contents of the reconstructed data include three parts—the yearly number,the occurring time and influential scope of every event.Some characteristics of the reconstructed data,temporal resolution,seasonal distribution and temporal evolution,are also discussed.

OVERVIEW OF SEVERE TYPHOON FITOW AND ITS OPERATIONAL FORECASTS

Severe typhoon Fitow(1323)brought persistent and heavy rainfall to Zhejiang and the Shanghai area after it made landfall at Fujian Province of China in October 2013,breaking the rainfall records of several counties and districts in Zhejiang.In this paper,we provide an overview of the characteristics of Fitow’s landfall,including its track,intensity,structural evolution,heavy rainfall,and wind.We also describe some of the associated disastrous impacts.Finally,we provide verifications of operational forecasts of its track,intensity and rainfall.Though the track and intensity is well predicted,the rainfall persistence and enhancement in the second stage in Shanghai and north Zhejiang areas are not predicted out at all.The analysis presented in this paper provides forecasters and researchers with some valuable information on Fitow,which could form a useful basis for further studies.