北京地区气温多尺度分析和热岛效应

Time scale analysis of tempreture and its urban heat island effect in Beijing

以北京地区20个气象观测站47年(1960-2006年)逐日的平均气温记录为基础,利用线性倾向估计、突变分析、小波分析等分析方法对北京地区气温的时空分布特征及其热岛状况进行了分析。研究表明:近47年来北京地区年平均气温变化呈上升趋势,7年滑动平均曲线表明这种上升趋势近年来稍有减弱。城市热岛效应明显,四季热岛效应的时间和空间均有差异。冬季热岛效应比夏季强,但夏季热岛效应呈现出多中心的现象。小波分析表明热岛强度存在3个周期变化。在25a左右的尺度上,进入21世纪春季和冬季相对较弱,夏季和秋季较强。

The change of temperature and characteristics of urban heat island effect were analyzed with climatology statistic methods called linear regression,Mann-Kendall and Wavelet Analysis based on meteorological data from 1960 to 2006 at 20 stations in Beijing area.The Mann-Kendall was applied to annual and seasonal temperature and UHI time series.The Mann-Kendall statistic test is a rank-based,nonparametric approach and has been widely used to estimate significance of long-term tends in hydro meteorological time series such as water quality,stream flow,temperature,precipitation.The results indicate that was an increasing trend of temperature in Beijing in the 47 years.Abrupt change analysis showed that： the temperature has the rising tend and the abrupt change happen in 1991.The difference is significantly in seasonal temperature,especially in spring and winter not in summer and autumn.Abrupt change analysis showed that： the temperature of winter has the rising tend and the abrupt change happen in 1980s.The other was happened in 1990s.The urban heat island effect in Beijing is typical.The UHI has the rising tend in recent 47 years in Beijing area.The rising tend over the significant level since early 1980s.The seasonal UHI is different too.UHI in winter is the highest,spring and autumn took the second place,summer is the lowest.However,the UHI has different hot center in summer.This is due to fast development of urbanization in recent years.However,the 7-year running mean curve showed that the UHI will decrease in the future.Abrupt change analysis showed that： the UHI rising tend is significant in spring,summer and autumn,weaker in winter.Wavelet Analysis showed that： UHI periodic variation is about 3 years.On the time scale of 25 years,the UHI in spring and winter relatively weak since 21st century,stronger in summer and autumn.