Study On The Variation Characteristics Of Climate Livability In Chengdu Under The Background Of Global Warming

In order to cope with the impact of global climate change on human health and population aging,and implement the Outline of "Healthy China 2030",in recent years,the state has proposed to build healthy cities and promote healthy China's development.Chengdu,as a first-tier city in the southwest of China,has developed rapidly in recent years,which is bound to have an impact on urban climate.But up to now,no analysis has been made on its climate livability.Therefore,based on the national demand and the shortcomings of previous studies on urban climate in Chengdu,this paper analyses the characteristics of climate change of single factors such as temperature,relative humidity,precipitation and wind speed in Chengdu under the background of global warming.At the same time,chosen the way to calculate the sensible temperature and divide the comfort levels based on the Golden Section,which incorporates more meteorological factors into the impact,this paper evaluates the climate comfort in Chengdu,qualitative and quantitative analysis of climatic livability is carried out from different perspectives of multiple factors.Main conclusions are follows through the analysis above:(1)In the past 37 years,the temperature in Chengdu has shown a significant fluctuating upward trend.After 2010,the upward trend of temperature has slowed down.From the interdecadal analysis,the annual average temperature has increased by 1.2 C,with the largest increase in spring,increasing by 1.7 C.In a word,the temperature rises obviously in spring,and the temperature rises slowly in the near future.(2)The annual precipitation in Chengdu decreased slightly before 2006,and then increased slightly.The number of precipitation days decreased significantly,and from the beginning of the new century,the number of precipitation days increasedslowly.(3)In the past 37 years,the relative humidity in Chengdu has declined significantly,especially after 2006.From the interdecadal analysis,the annual average relative humidity decreased by 7.9%,the spring trend was more significant,the cumulative decline was 9.8%,the most significant decline was 12.2% in March.If the daily average relative humidity is between 50% and 80% as the relative humidity comfortable day,the relative humidity comfortable days in Chengdu have increased significantly in the past 37 years,especially since 2006.From the interdecadal analysis,the cumulative increase of annual days is 134 days,and that of summer is 42.2 days.The significant decline of relative humidity fluctuation and the significant increase of relative humidity comfort days both directly indicate that the humid climatic conditions in Chengdu have been significantly improved,which is conducive to the improvement of livability.(4)The results of comfort analysis show that:in Chengdu,the number of days in the generalized comfort zone has increased fluctuatively in recent 37 years.From the interdecadal analysis,the increase of days in spring is the largest,with a total of 10.89 days.The number of days in partial cold area decreased significantly in a fluctuating manner,with the largest cumulative decrease in spring,which was 10.77 days.The daily number of partial heat area increased significantly in a fluctuating manner,and the cumulative increase in summer was the most obvious,12.79 days.In a word,the increase of the generalized comfort days and the decrease of fluctuation patterns of the cold region days in Chengdu are beneficial to the improvement of livability.In summary,the significant declining trend of relative humidity fluctuation and the significant increasing trend of relative humidity comfort day fluctuation directly indicate that the humid climate conditions in Chengdu have been improved obviously,the increasing of generalized comfort day fluctuation and the decreasing of partial cold area fluctuation,all of them are beneficial to the improvement of climate livability in Chengdu.Therefore,the results of this study can provide an important scientific basis for promoting the construction of local healthy cities,attracting more foreign personnel to the local health tourism,and promoting the development of localhealth tourism industry.