Assessment of Economic Damage Risks from Typhoon Disasters in Guangdong, China

Guangdong is a developed province in China, but suffers from frequent typhoon disasters which cause great economic loss. Quantitative regional risk assessment of typhoon disasters is important for disaster prevention and mitigation. According to direct economic loss and typhoon intensity information, we established a typhoon disaster loss rate curve using data from 1954 to 2008. Based on GIS spatial module, the economic vulnerabilities of different intensity typhoons were calculated for 98 counties in Guangdong Province. Different intensity typhoon landing frequencies in Guangdong were also calculated, and used to indicate typhoon disaster probability. A risk assessment model was established to assess economic loss risk under different intensity typhoons in Guangdong. The results show that economic loss risk caused by typhoon is more than 10 thousand million CNY; according to typhoon intensity grade, economic risk is up to 10.467, 14.429, 7.753 and 13.591 thousand million CNY for slight, light, medium and severe typhoons, respectively. The Pearl River Delta is the highest risk region, especially Guangzhou, Dongguan, Shenzhen, Zhongshan and Zhuhai. Risk value decreases from Pearl River coastal outfall to the inland in a radial pattern. Inland areas far from coastal counties have lower risk, and the risk value is less than 50 million CNY. When typhoon intensity increases from slight to medium, the risk in western is higher than in eastern parts, but when typhoons become to severe, the risk value in eastern Guangdong part is higher than in the west.

Typhoon disaster risk zoning for China’s coastal area

Previous studies on typhoon disaster risk zoning in China have focused on individual provinces or small-scale areas and lack county-level results.In this study,typhoon disaster risk zoning is conducted for China’s coastal area,based on data at the county level.Using precipitation and wind data for China and typhoon disaster and social data at the county level for China’s coastal area from 2004 to 2013,first we analyze the characteristics of typhoon disasters in China’s coastal area and then develop an intensity index of factors causing typhoon disasters and a comprehensive social vulnerability index.Finally,by combining the two indices,we obtain a comprehensive risk index for typhoon disasters and conduct risk zoning.The results show that the maximum intensity areas are mainly the most coastal areas of both Zhejiang and Guangdong,and parts of Hainan Island,which is similar to the distribution of typhoon disasters.The maximum values of vulnerability in the northwest of Guangxi,parts of Fujian coastal areas and parts of the Shandong Peninsula.The comprehensive risk index generally decreases from coastal areas to inland areas.The high-risk areas are mainly distributed over Hainan Island,south-western Guangdong,most coastal Zhejiang,the coastal areas between Zhejiang and Fujian and parts of the Shandong Peninsula.

TYPHOON DISASTER AND ITS RISK ASSESSMENTIN CHINA

On the basis of the typhoon disaster data from 1989 to 1994, this thesisanalyzes the main features of typhoon disaster in China, and makes its risk assessment.It concludes that the typhoon disaster has brought about the most serious damages in Zhejiang and Guangdong Provinces. Generally, typhoon occurs from May to October in China,most from July to September, mainly in August. Annual variation of typhoon disaster is consistent with annual variation of landing typhoon number.With the economy development in coastal area,the economic loss of disaster also rises.Risk assessment shows that Zhejiang and Guangdong Provinces areprone to high possibility of typhoons, the anti-typhoon disaster ability of Zhejiang and Hainan Provinces is relatively low

Design Code Calibration of Offshore Platform Against Typhoon/Hurricane Attacks

Hurricanes Katrina and Rita resulted in the largest number of platforms destroyed and damaged in the history of Gulf of Mexico operations. With the trend of global warming, sea level rising and the frequency and intensity of typhoon increase. How to determine a reasonable deck elevation against the largest hurricane waves has become a key issue in offshore platforms design and construction for the unification of economy and safety. In this paper, the multivariate compound extreme value distribution （MCEVD） model is used to predict the deck elevation with different combination of tide, surge height, and crest height. Compared with practice recommended by American Petroleum Institute （API）, the prediction by MCEVD has probabilistic meaning and universality.

Multiscale simulation of the urban wind environment under typhoon weather conditions

Accurate simulations of planetary boundary layer(PBL)winds in urban areas require combining meteorological knowledge and fine-grained geometrical information.Computational fluid dynamics(CFD)is widely used to assess pedestrian wind comfort and wind disasters in planning resilient cities.However,the CFD-predicted PBL is highly affected by the inflow boundaries.Wind profiles under extreme weather conditions,such as tropical cyclones,can hardly be determined,and associated uniform logarithmic or power law expressions have not been obtained.In this study,urban wind flow over mountainous terrain was simulated using a one-way nested simulation approach between mesoscale and microscale models.The inflow wind speed,turbulence scalars,and potential temperature in the CFD code are sustained by the numerical weather prediction(NWP)model.Methodologies considering typhoon weather conditions were examined to improve the numerical accuracy in determining mesoscale typhoon structures and pedestrian-level wind conditions.The numerical errors were quantified in mesoscale and microscale formulations.A new tendency assimilation was proposed by incorporating local-scale observations into the CFD domain.This approach entailed empirical mode decomposition to quantify the mean wind speed differences between the observations and NWP results,which were then extrapolated to NWP-CFD nested interfaces via multiplication by the spatial correlation coefficient.The numerical performance was validated against both on-site observations for meteorological purposes and wind profiles retrieved from the experimental LiDAR of the landfalling typhoon Haima.The simulated wind field exhibited an increased accuracy in the local urban area.More specifically,the index of agreement in wind speeds was improved from 0.28 to 0.72,and the mean absolute errors were reduced from 5.46 m/s to 1.89 m/s.

Hazard Footprint-Based Normalization of Economic Losses from Tropical Cyclones in China During 1983–2015

Loss normalization is the prerequisite for understanding the effects of socioeconomic development,vulnerability, and climate changes on the economic losses from tropical cyclones. In China, limited studies have been done on loss normalization methods of damages caused by tropical cyclones, and most of them have adopted an administrative division-based approach to define the exposure levels. In this study, a hazard footprint-based normalization method was proposed to improve the spatial resolution of affected areas and the associated exposures to influential tropical cyclones in China. The meteorological records of precipitation and near-surface wind speed were used to identify the hazard footprint of each influential tropical cyclone. Provincial-level and national-level(total)economic loss normalization(PLN and TLN) were carried out based on the respective hazard footprints, covering loss records between 1999–2015 and 1983–2015, respectively.Socioeconomic factors—inflation, population, and wealth(GDP per capita)—were used to normalize the losses. A significant increasing trend was found in inflation-adjusted losses during 1983–2015, while no significant trend was found after normalization with the TLN method. The proposed hazard footprint-based method contributes to amore realistic estimation of the population and wealth affected by the influential tropical cyclones for the original year and the present scenario.

THE IMPACT OF TROPICAL CYCLONES ON CHINA IN 2016

In 2016, the Northwest Pacific and the South China Sea registered the genesis of 26 tropical cyclones. 8 of them, including NEPARTAK(1601), MIRINAE(1603), NIDA(1604), DIANMU(1608), MERANTI(1614),MEGI(1617), SARIKA(1621) and HAIMA(1622), made landfall over China's coastal areas. The number one TC of 2016, NEPARTAK, was named on July 3. Although no typhoon generated in the first half of this year,which means 4.6 incidences less compared with the same period of a normal year, more tropical cyclones made landfall over China(the historical average in the same period of 1949-2015 is 6.7). And these 8 tropical cyclones had an averaged intensity up to 40.6 m/s, significantly enhanced compared with the multi-year average of 32.8 m/s.The death toll from the 11 tropical cyclones affected China in 2016 is 206. MERANTI was the most destructive one in 2016, which brought up the largest numbers of affected and evacuated population, damaged houses and direct economic losses. In 2016, China Meteorological Administration(CMA) 24-120 h mean official track forecast errors were 66, 127, 213, 292 and 364 km, respectively. The 24 h track forecast error has been kept within 70 km in two consecutive years.