The study on heat island effect in Beijing during last 40 years

TLDR: The results show that the difference of mean daily temperature between city and suburb is the largest on 24 December in 1995 during the last 4 0 years, and an obvious 12 years cycle of mean annual temperature is found.

Abstract: Variations of mean temperature in Beijing city are ana ly zed in this paper.The results show that the difference of mean daily temperature between city and suburb is the largest on 24 December in 1995 during the last 4 0 years,and the mean daily temperature in the city is 4.6℃ higher than that in the suburb;the difference of temperature between the city and the suburb is the utmost in winter season and the mean seasonal temperature in the city is 1.11℃ higher than that in the suburb,while the difference is the least in spring seaso n,and the temperature in the city is 0.26℃ higher than that in the suburb;for t he inter-annual variability of temperature,the difference of temperature is lit tle from 1961 to 1977,while the difference is great from 1978 to 2000,and the te mperature in the city is 0.62℃ higher than that in the suburb,so the heat islan d effect is reinforced from 1978 to 2000;the difference of temperature is the le ast in 1960's,and the temperature in the city is 0.13℃ higher than that in the suburb,whereas the difference is the maximal in 1990's,and the temperature in th e city is 0.78℃ higher than that in the suburb;the number of high temperature d ays(≥35℃)is going up obviously in recent years,but the highest temperature is not changed greatly,and the highest temperature is higher than 38℃ only in 1997 ,1999 and 2000. The mean annual temperature is increasing apparently during the last 40 years,and it is increasing by 0.43℃/10ɑ in the city and 0.21℃/10ɑ in the suburb,an obvious 12 years cycle of mean annual temperature is found.