| China is located in the eastern part of Asia and the Pacific west bank,as a result of climate warming and accelerated the process of urbanization increased the frequency and strength of extreme heat,but the study on the influence of the soil moisture condition on extreme heat was very scarce.At the same time,the urban aging problem was increasingly serious,people gave more and more attention to extreme heat and its health problems.Based on daily temperature and precipitation data from 756 Chinese stations during 1960-2012,by dividing china into 5 sub-regions and Nanjing as a typical city,using time-trend analysis and Mann-Kendall methods,the characteristics of the space-time distribution of precipitation,highest temperature and the summer of 3-month SPI(Standardized Precipitation Index),6-month SPI and %HD(The percentage of hot days)and its abrupt test were analyzed in each region of China.Using the quantile regression and correlation analysis method,the impact of soil moisture condition on extreme heat were analyzed in China and its five climate zones and Nanjing respectively.Based on the data of daily mortality and meteorological factors in Nanjing City from 2004 to 2010,the deaths' cause were classified,the distribution characteristics of breathing,circulation,tumor diseases were analyzed,the frequency of heat wave to be counted.At the same time,using the NCEP-Department of Energy reanalysis II analyzed the circulation feature of two heat process that picked out.By using multilateral approach,such as moving average,the impact of heat wave on local human health was studied in Nanjing City.By using GAM(generalized additive model)of time series adjusting for the secular trend,short-term fluctuation,weekday,national holidays,the impact of heat wave on circulatory system disease deaths was quantitatively analysed.The main results were as follows:(1)The precipitation and highest temperature over China mainland were presented obvious periodicity in the past 53 years.Precipitation mainly concentrated in the summer,followed by the spring and autumn season,fewer in winter.the change trend of average rainfall were regional difference,presented the spatial distribution of east more than west,south more than north,from southeast coast to inland northwest gradually reduce.The precipitation mutation of China mainland's five climate zones happened in different years,precipitation has increased and decreased.However,China mainland's highest temperature on the whole is on the rise,the highest temperature in summer was generally on the high side,the spring and autumn was mild,generally low in the winter,the difference of highest temperature of the north and the south is very big.The highest temperature mutation of China mainland's five climate zones happened around 1996 from low temperature to high temperature,rise significantly after 2006.(2)The relationship between %HD and 3-month SPI,6-month SPI are basically identical.The smaller the SPI,the greater the %HD.Due to soil surface humidity changes,the high percentile of summer %HD more intense than other low percentile.In other words,when dried soil conditions,the value %HD range is bigger.The relationship between the higher quantile of %HD(tail)and the SPI in 3 months scales was more clear in China mainland and Nanjing.In terms of geographical area,In terms of geographical area,the big absolute value of the slope of quantile regression line correlation coefficient between SPI and %HD mainly concentrated a certain range of the dividing line of monsoon region and non-monsoon region.In five climate zones in China mainland,the relationship between SPI and %HD was the most significant in Semiarid and Dry subhumid area.It means in the dry and wet transition region,antecedent dried soil can show the occurrence possibility of extreme high temperature event is very large.(3)Highest temperature distribution looked like a inverted ‘V' in Nanjing City,the highest temperature in summer was generally on the high side,the spring and autumn was mild,generally low in the winter,The highest temperature of the four seasons the summer,autumn,spring,winter in that order.The highest temperature on the whole is on the rise in Nanjing City,especially in the spring.The inter-decadal feature of highest temperature distribution looked like a ‘?'.the highest temperature has large,medium and small cycles.The mutation of highest temperature of the four seasons in Nanjing happened around 1990 s from low temperature to high temperature from low temperature to high temperature.(4)Circulatory system,cancer and respiratory system disease were common diseases that were harm to human health,have a lot of people die duo to these three kinds of diseases in Nanjing.Respiratory and circulatory system disease mortality in winter half year is higher than the summer half year,both diseases mortality in winter appeared peak.However,the respiratory system and circulatory system disease in On August and September appeared a small wave of summer half year.Relatively,tumor mortality monthly fluctuations was up and down,without change law.Climate warming maybe has caused circulatory system disease happened,the death rate of circulatory system on an upward trend and respiratory system disease mortality was declining.Tumor relative to the circulation and respiratory system disease was less sensitive to temperature change.These three diseases except the tumor was closely related to meteorological elements.The lowest temperature was below 18?,a 1? drop would cause all deaths from circulatory system disease to increase 2.65%.The average temperature was below 12.5?,a 1? drop would cause all deaths from circulatory system disease to increase 2.80%.The highest temperature was below 24?,a 1? drop would cause all deaths from circulatory system disease to increase 2.33%.Low temperature-humidity is fatal factors of the different populations of circulatory system diseases in Nanjing.(5)The high temperature days were 123 days and the heat wave weather process occurred 15 times in Nanjing City from 2004 to 2010,respectively.The influence each high temperature heat caused of heat wave on different populations of circulatory system disease deaths was difference.In nanjing,the highest temperature exceed its 90th(extreme heat has happened),and in the day and after a few days,circulatory system disease,tumor,the total number of deaths immediately increased.At the same time,when the daily circulatory system disease,tumor,the total death toll is far more than its' average,can also be found the daily highest temperature exceeds its 90 th in the day or before the days,we can use the 90 quantile of highest temperature and disease deaths to define each other.A 1? increment in highest temperature would cause all deaths from circulatory system disease to increase 0.981% in summer.During heat wave,a 1? increment in highest temperature was significantly associated with all deaths from circulatory system disease on value of OR 12.179.The crowd of circulatory system disease is sensitive to high temperature hot weather.During heat wave,the impact of highest temperature on the different populations of circulatory system disease was harmful,had a certain lag.Impact appeared as: female more than male;Under the age of over 60 years of age greater than 60;Multi-factor model is greater than the single factor model.During heat wave,the main effect of the highest temperature is fatal factor of circulatory system diseases in Nanjing.The results of this study can improve the predictability of extreme heat,for the warning and forecast of extreme heat provide certain reference.At the same time,find out the susceptible disease of the change of the weather,helps to take corresponding effective preventive measures to reduce health hazards caused by heat. |
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