Temporal And Spatial Distribution Of Population And Disaster Exposure Assessment In LECZ, China

Coastal lowlands or low elevation coastal zones (LECZ) is a continuous strip along coastal areas whose altitude is less than 10m. Coastal lowlands is an important but fragile eco-sensitive region where it has density higher population density and frequent natural disasters. In this thesis, the spatial boundary of coastal lowlands in China was determined based on the data of the SRTM 90m DEM, Grid data of world population, Chinese administrative division map and disaster data from hotspots by using GIS. Besides, we also analyzed the spatial-temporal distributions of population and population exposed to natural disasters in coastal lowlands.The results and conclusions of this thesis were as follows:(1)The total area of Chinese coastal lowlands was 161,491,819,056 m2, which accounted for about 1.7% of the total area of national land.Fourteen provinces and more than 350 counties were covered by coastal lowlands. The biggest coastal lowlands area was Jiangsu province which accounted for 63.16% of the total land area of Jiangsu province. The area of coastal lowlands was 63,749,258,407 m2 and accounted for about 39.5% of the total coastal lowlands. The smallest coastal lowlands area was Macao and the area of coastal lowlands was 9,124,350m2. However, it accounted for about 35.68% of the total land area of Macao. Seen from the area proportion of province, the coastal lowlands with the biggest proportion was Shanghai province and Tianjin province, which accounted for about 97.91% and 82.79% of the total land area, respectively, and Guangxi province was smallest, which only accounted for about 0.41% of the total area of Guangxi Province.(2) People lived in coastal lowlands were 119,498,023 according to raster data of population in 2000, which accounted for about 22.1% of the total population of the provinces in coastal lowlands and about 9.3% of the total population in China. The largest population of coastal lowland provinces was Jiangsu and Guangdong province, and there were 46,227,246 and 16,728,791 people, respectively. Seen from the population proportion of coastal lowlands in provinces of the these provinces, Shanghai was about 99.50%, and Tianjin is about 91.77% and Guangxi province was only about 0.64%. (3) People lived in coastal lowlands increased with time change. Most notably change was in Guangdong Province. The largest annual population growth segment was from 1990 to 1995, and the growth rate was 40.52%, then the growth rate gradually slowed to 20.64%,19.32%,17.76%,12.71% every 5 years, but still higher than the growth rate of other mainland provinces. Expect for Hebei, Tianjin and Jiangsu, the population proportion in costal lowlands provinces increased.(4) Tropical cyclones occurred most frequently are the coastal lowlands in south of Zhejiang province, and rapid decreased from the coastal lowlands in north of Yangtze river. The average frequency of tropical cyclones in the coastal lowlands from the south of Zhejiang province was greater than 8.0, and it was less than 4.0 from the north of Jiangsu province. The death risk in the coastal lowlands from the south of Yangtze River was higher than that in the north of Yangtze River. The death risk was zero in Hongkong and Macao. The death risk in the coastal lowlands in Jiangsu province was higher than that in Fujian province, and its death risk was 6.0. Overall, the distribution characteristics of both total economic loss risk and the risk of economic loss ratio in southern area were higher than that in northern area.(5) Flood occurred most frequently were the coastal lowlands in Yangtze River Delta and Zhujiang Delta, and the risk level was above 8.0. The highest death risk occurred in the coastal lowlands in Jiangsu, Shanghai, Zhejiang, Taiwan and Guangdong, and their death risk ratio was above 8.0. The death risk ratio in Hongkong and Macao was zero. Seen from the economic loss risk of coastal lowlands, the lowest area was Aomen, that in the coastal lowlands in Jiangsu, Shanghai, Zhejiang, Taiwan and Guangdong was higher, and that in Guangdong province was highest. That in other provinces was from 5.0 to 7.0.(6) Proportion of the population in the high-frequency areas of tropical cyclones from the south of Shanghai was greater, the proportion in Shanghai and Zhejiang was greater than 70%, and that such as in Fujian, Guangdong province was greater than 95%. Meanwhile, proportion of the population in the high-frequency areas of tropical cyclones from the north of Jiangsu province was lower. The population in coastal lowlands mainly distributed in low-frequency area of flood from the north of Jiangsu. In the coastal lowlands from the south of Shanghai, except for Taiwan and Hainan, the proportion of the population in the high-frequency areas of tropical cyclones were greater, which in some regions approached or reached 100%.