Global Warming, Urban Heat Island, Heat Wave And Human Health

Human beings are closely linked to atmdspheric environment via their heat budget. Extreme thermal conditions can harm the health of people with limited capacity for acclimatization. The ageing of the population, together with the potential effects of global warming and urban heat island, may exacerbate the threats to human health posed by thermal stress in the future. Therd is growing interest concerning the heat wave and its heath impacts. This paper summarizes the main findings on the investigation of the characteristic of the spatial and temporal distribution of heat wave at the capital cities of main provinces in China and; the urban heat island, heat waves and Effects of heat stress on human health in Shanghai as a showcase city; the development and improvement of the heat/health warning techniques, as follows:(1) The Yangtze River basin is the high frequency heat wave attacked area with long duration (+ 5 days) of heat wave period. The temperature increase at the main capital cites of province in China appears a "increase - decrease - increase " pattern from southeast to northwest, but the most cities suffered temperature increasing in the recent years, while the onset and density of heat wave is different in the different regions.(2) The mean maximum temperature, extreme temperature and hot days in summer measured at the urban and sub-urban sites all appeared increasing trends, with the bigger value at urban sites and small value at the rural sites, with bigger temperature increase in the urban site than that in the rural sites increase trends weather. Urban heat island induced temperature increase excesses the regional warming which lead to more hot days, higher extreme temperature and longer duration, but the wide covered high temperature did not increase so much.(3) The perceived temperature derived from the human heat balance model, which included the thermal and physiological process between human and external environment can be used to evaluate heat pomfortable condition theoretically. The mortality in the heat wave has close relation with perceived temperature with the more excess deaths in the longer heat stress conditions(PET>41℃).(4) The elevated mortality associate with maximum temperature, minimum temperature, durations and the timing of heat wave. The ranking of death causes has shifted, and the cause-specific excess mortality has increased during the heat wave period. It is believed that circulatory and respiratory disease; heat stroke, heart disease and chronic lung diseases are common heat-associated diseases. The excess mortality in the downtown area is bigger than that in the rural area, which is closely associated with urban heat island (UHI) index. The investigation of two strong heat waves in 1998 and 2003 confirms that the increased levels of daily mortality are often associated with very hot weather. While air pollution might account for some of the excess mortality, the relationship between temperature and mortality is stronger than that between atmospheric pollution and mortality. The improvement of living conditions within Shanghai and the wider availability of air-conditioning have likely decreased the populations' vulnerability to extreme heat.(5) Maximum temperature, Heat Index, Perceived Temperature and Discomfort Index (DI) has been verified that all these thermal indices had close relationship with elevated mortality. Taking into consideration the Long term and short term acclimation of the people's vulnerability to the heat environment, A stepwise regression model, including the variables of relative threshold temperature, population average temperature, and cumulated effective temperature, etc. , have been explored to depict the heat/health relations. It has been evaluated that the new developed and improved heat/health warning systems (ReTmax, RePET, SSC_New) have the better capacity than the original early version of SSC-Based HHWS.(6) A 3D Urban Boundary Layer (UBL) Model has been used to simulated the Urban Heat Island and other UBL meteorological parameters through the improvement of the surface heat budget process by calculating UBL dynamic and thermal parameters on the different categories of land cover, derived from the high-resolution TM remote sensing date. And, the human-environment heat budget model also has been integrated to the UBL model to calculate the distribution of the perceived temperature, which can be technical supports to the sub-area urban heat/health warnings.