关键词: 热岛效应, 高温日数, 年代际变化特征

Abstract:

Variations of mean temperature in Beijing city are analyzed in this paper by using climatological data of 4 stations in city and 3 stations in suburb.  We found that the difference of temperature was great in daily.seasonal.annual and decade.the difference of temperature between city and suburb was largest in winter and the mean seasonal temperature in city was higher 1 .11 0Cthan that in suburb .while the difference was smallest in firing;For the inter一annual variability of temperature .the difference was little from 1961 to 1977 .while the difference was great from 1978 to 2000.so the heat island effect was reinforced from 1978 to 2000;the did ference of temperature was least in 1960's .whereas the difference was maximal in 1990's;the number of high temperature day() 35冯was going up obviously ,but the highest temperature was not changed greatly .the mean annual temperature was increasing apparently during last 40 years .and it was increasing by 0. 43/10a in city and 0.21/10a in suburb. the sunshine time decreased obvr
ously in Beijing .and the decreasing range was 78. 9 hours 10a during the last 40 years.and the difference in autumn between city and suburb
was largest in whole year.  The precipitation also reduced recent years .furthermore the change of yearly precipitation was great .and the d}
creasing range of precipitation was 45. 2mm/ 10a in Beijing city.  Following the development of city.the days when the precipitation was less
than lOmm were more in city than in suburb.  The visibility was great in February.May.September and October in B句ing.the number of
low visibility(< 4km) was increasing ,the visibility was decreasing in recent years and the visibility in city was obviously lower than in sulr
urb.  The relative humidity was also decreasing in recent years in city .and the decreasing range was 1.6%for every 10 years.further rrxrre
the relative humidity in city was less than in suburb .it showed dry island effect.

Key words: the heat island effect , the number of high temperature day , inter一annual change