上海百余年来气温日间波动特征及城市化影响

Two-day Fluctuations of Temperature and the Impacts of Urbanization in Shanghai during the Period 1873-2009

基于上海市区(徐家汇)气象站1873年-2009年和上海10个郊县气象站1960年-2009年逐日气温数据,利用气候统计诊断方法分析了上海最高和最低气温在两日间(简称日间)的波动特征及城市化影响,结果表明:1873年-2009年期间,上海最高气温日间降温日数逐渐增多,升温日数逐渐减少,最低气温日间降温日数呈多-少-多-少的年际变化,日间升温日数则呈少-多-少-多的年际变化。上海最高气温日间降温和升温幅度、降温和升温≥5℃日数和最低气温日间降温幅度、降温≥5℃日数都呈现出先增加后减少的年际变化,最低气温日间升温幅度和升温≥5℃日数在20世纪30年代前变化很小,从20世纪60年代至今明显减少。上海城市化增加了最高气温的日间波动幅度,并减少了最低气温的日间波动幅度,使得最高气温日间升温≥5℃日数增加和日间降温≥5℃日数减缓减少,最低气温日间降温和日间升温≥5℃日数均减少。

Global average surface temperature has increased by 0.7°C over the 20th century and is projected to increase within the range of 2-6°C in the 21st century.Numerous studies indicated that the maximum and minimum temperature changes show obvious asymmetric characteristics of spatial distribution and the rate of linear increasing tendency.However,the two-day fluctuation of daily maximum and minimum temperature,which would have important impacts on municipal water supply,power supply,and human health,does not seem to be well investigated.Based on daily maximum and minimum temperature data of the Xujiahui station during the period 1873-2009,and those of 10 suburb stations during the period 1960-2009 in Shanghai,the characteristics of two-day fluctuation of daily maximum and minimum temperature and the impacts of urbanization on them were examined with climatologically statistical diagnosis methods.Results indicate that over the period 1873-2009,days with the two-day falling of daily maximum temperature increased gradually and those with the two-day rising decreased gradually.Days with the two-day falling of daily minimum temperature showed a more-less-more-less inter-annual variation,and days with the two-day rising of daily minimum temperature showed a less-more-less-more inter-annual variation.The two-day rising and falling range of daily maximum temperature,days with the two-day rising and falling of daily maximum temperature of no less than 5 °C,and the two-day falling range of daily minimum temperature and days with the two-day falling of daily minimum temperature of no less than 5 °C all increased firstly and then decreased during the period 1873-2007.However,the two-day rising range of daily minimum temperature,days with the two-day rising of daily minimum temperature of no less than 5 °C remained fairly invariant before the 1930s,and decreased obviously since the 1960s in Shanghai.Urbanization increased the two-day fluctuation range of daily maximum temperature and decreased the two-day fluctuation range of daily minimum temperature,which resulted in increases in days with the two-day rising of daily maximum temperature of no less than 5 °C and slower decreases in days with the two-day falling of daily maximum temperature of no less than 5 °C,and resulted in decreases in days with the two-day rising and falling of daily minimum temperature of no less than 5 °C in Shanghai