| Since the 1990 s, the global extreme high-temperature occurred frequently, and presents the characteristic of strength, wide range,high frequency, etc. the extreme high-temperature and high-temperature days reached a new number of record, and even high-temperature disasters occurs every year in part of areas. This worldwide day of high temperatures attracted the attention of the scientific community and relative international organizations. As a common disastrous weather of high temperature in summer, with global warming and the speeding up of urbanization, the increased frequency of extreme high-temperature or continuous high temperature, bring great harm and negative impact to the human health and social economic development.Chongqing is known as a “furnace”, the high temperature in summer is one of the main climatic characteristics of Chongqing. Chongqing hot not only strength but also last for a long time, in recent years, the frequent extreme weather events such as high drought, extreme maximum temperature reached a new record, has a serious influence on the local social economic development and people’s life. Therefore study the spatial distribution characteristics of high-temperature disaster in Chongqing, space-time evolution law and risk assessment is particularly necessary.In this paper, on the basis of summarizing the theory and method of predecessors’ research, based on 34 local sites’ daily maximum temperature monitoring data of Chongqing Municipal City from 1960 to 2015, the days of high-temperature( which daily maximum temperature is more than or equal to 35℃)have been extracted and time series have been analyzed by using Excel, Mann Kendall mutation test and Morlet wavelet analysis method. Get the spatial distribution features of high-temperature disaster by using GIS spatial interpolation method. Secondly, based on the analysis method of high-temperature disaster, estimate high temperature strength-frequency by using Pearson- Ⅲ type probabilistic model, constructing the disaster risk evaluation index system about high-temperature disaster in the aspects of hazard, exposure,sensitivity, coping capacity. With comprehensive use of entropy method and analytic hierarchy process(AHP) to determine index weight of every level, based on the concept of comprehensive risk model "R = H*V" and mathematical model of fuzzy matter-element, to evaluate the hazard, exposure, sensitivity, vulnerability, coping capacity, risk of Chongqing high-temperature disaster and sorting the risk quantitatively evaluation respectively. In this paper, conclusions have been drawn as follows:(1) The temporal distribution characteristics of high temperature day is as follows:high temperature day throughout May to September, mainly concentrated in July and August, distribution pattern showed a trend of obvious normal distribution; Recent 56 years, high temperature days change between 9-56d/a, have an obvious increasing trend on the whole, at the rate of 1.46 d/10 a; there are multiple time scales of periodic oscillation on the high temperature days, including three quasi oscillation period,such as 3, 11, 30 etc. High-temperature day mutation in 2000-2001, the peak of regional high temperature strength appeared in 2006 and 2011; there is a obvious inter-generational change of high temperature days in Chongqing from 1960 to 2015. In general, the number of high temperature days is less in the 1980 s, in recent five years, have more high temperature days.(2) The spatial distribution characteristics of high temperature days in Chongqing is as follows: the days of high-temperature which is more than or equal to 35℃change between the 2-44d/a. River valley of the Yangtze river, Jialing river, Qijiang and the Xiaojiang Valley is the high temperature areas, there are three relatively high incidence areas, the County in the North-East of Chongqing such as Kaixian, Yunyang, Wushan,Wuxi, the central part of Chongqing, such as Fengdu and its nearby area, Wansheng as the center in the Western southerly along the Yangtze River area. The southeast and northern mountainous areas of Chongqing have fewer high temperature days.(3) The hazard level of high-temperature disaster in Chongqing is higher as a whole, in the 38 counties, 8 counties belongs to the senior hazard, 21.05% of the total.11 counties belong to the more advanced level, 28.95% of the total; 4 counties belong to the Mid-range, 10.53% of the total; 15 counties belong to the Low and lower level,39.47% of the total. From the perspective of the spatial distribution of high-temperature disaster hazard, the Yangtze river and Jialing river, Xiaojiang and Qijiang valley has a higher grade of the area, including the County in the North-East of Chongqing such as Kaixian, Yunyang, Wushan, Wuxi, the central part of Chongqing, such as Fengdu and its nearby area, Qijiang and Banan as the center of Western partial south along the YangtzeRiver areas three risk are the higher grade areas. The County in the southeast of Chongqing such as Shizhu, Qianjiang, Youyang, Xiushan and the mountainous area in the northeast of Chongqing where the hazard level is lower; major city hold in high hazard level.(4) The vulnerability level of high-temperature disaster of whole in Chongqing is higher, in the 38 counties, 9 counties belongs to the senior grade, 23.68% of the total. 6counties belong to the more advanced level, 15.79% of the total; 14 counties belong to the Mid-range, 36.84% of the total; 9 counties belong to the Low and lower level,23.68% of the total. The spatial distribution of Vulnerability is more complex, there is no obvious distribution pattern. On the whole, the level of vulnerability in northeast area is higher, basically exceed average level; three districts’ Vulnerability at a low level,such as Jiangbei, Jiulongpo and Changshou; Rongchang, Bishan, Yuzhong, Nanan,Wulong and Xiushan are in lower level; Yubei, Dadukou, Banan, Fuling, Pengshui,Kaixian, Chengkou, Wushan and Fengjie counties.(5) The risk level of high-temperature disaster of whole in Chongqing is higher, in the 38 counties, 7counties belong to the senior grade, 18.42% of the total; 9 counties belong to the more advanced level, 23.68% of the total; 9 counties belong to the Mid-range level, 23.68% of the total; 9 counties belong to the lower level, accounts for23.68% of the total, 4 counties belong to the low-level, 10.53% of the total. From the perspective of the spatial distribution of high-temperature in Chongqing disaster risk,the Yangtze River and Qijiang Valley is the area of high temperature and highe level of risk, the County in the North-East of Chongqing, including Kaixian, Wanzhou, and Wushan. The central part of Chongqing, such as Fengdu and its nearby area, Qijiang and Banan Distric, in the west south region are the higher hazard level area. The County in the southeast of Chongqing such as Qianjiang, Youyang and Xiushan, where are the low value of the level of risk; the central of city hold in higher hazard level, exceed the Mid-range level. |
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