Abstract:

Based on climate observation (daily mean temperature data etc.) from 1961 to 2015 and regional climate model results from 2016 to 2099 under RCP4.5 and RCP8.5 scenarios, the climate comfort index of Yunnan province was calculated, then the spatial and temporal evolution and influence factors were investigated by linear trend and path analysis, finally the projection for future trends was made. The results shows: (1) The number of comfort days for Yunnan regional average accounted for 55% of year-round total days, which presented a decrease trend in spatial distribution from south to north with the biggest number of days in summer. The number of chill days came second, accounted for 23% of annual total days, and showed an increase trend from south to north with the biggest number of days in winter. The number of cold days held the proportion of annual days with 20% (being slightly less than that of chill days), while the number of hot days only accounted for 1%. (2) The number of chill/comfort days in Yunnan showed an obvious decreasing/increasing trend during 1961-2015, and the cold and hot days both showed no significant trend. (3) The temperature was the main factors of change of Yunnan climate comfort days, then was the wind speed, the relative humidity will influence the change of comfort days just in the case of high temperature. (4) Under RCP4.5 and RCP8.5 scenarios, during 2016-2099, the spatial and temporal evolution of chill/comfort days in Yunnan showed a/an decreasing/increasing trend, the spatial of cold days showed a decreasing trend, the temporal evolution of cold days showed an increasing trend in northwest of Yunnan but a decreasing trend in other areas, the hot days showed an increasing trend in the south of Yunnan.

Key words: Yunnan province, Climate comfort days, Spatial and temporal change, Projection for future trends