1873—2009年上海气温日较差变化及其影响因素

利用1873—2009年中国上海市11个气象站地面气象观测资料和1951—2009年北极涛动指数、1873—2000年西伯利亚高压强度等资料,分析了上海地区气温日较差的时间变化特征,以及大气环流异常变化、其他气象要素变化和城市化发展对气温日较差的影响。结果表明：过去137 a,上海气温日较差呈显著减小趋势,减小幅度为0.15℃/10 a。上海四季气温日较差均呈现出显著下降趋势,其中秋季气温日较差下降幅度最大,冬季气温日较差下降幅度最小。近60 a来,北极涛动指数表现出从负位相向正位相转变的趋势;而近130 a来,西伯利亚高压强度表现出由正距平向负距平转变的趋势,导致中国上海最低气温上升幅度大于最高气温的上升幅度,进而导致气温日较差的减小。在四季及全年,上海气温日较差的减小与日照时数的减少呈显著正相关,而与降水量的增加呈负相关。城市化对气温日较差的减小有明显影响。

Changes of diurnal temperature range and its influencing factors from 1873 to 2009 in Shanghai

Based on the meteorological observation data from 11 weather stations from 1873 to 2009 in Shanghai,the arctic oscillation indices from 1951 to 2009 and the Siberian high intensity data from 1873 to 2000,the temporal changes of diurnal temperature range（DTR）,the abnormal changes of atmospheric circulation,the changes of other meteorological elements and the effects of urbanization development on DTR were analyzed.The results indicate that the DTR decreases significantly in the past 137 years in Shanghai,and the rate is 0.15 ℃ per 10 years.The seasonal diurnal temperature ranges are also in decreasing trends.The maximum and minimum decreasing rates of diurnal temperature ranges occur in autumn and winter,respectively.The arctic oscillation indices change from the negative phase to the positive phase in recent 60 years,while the Siberian high intensity is from the positive anomaly to the negative anomaly in recent 130 years.As a result,the increasing amplitude of the minimum temperature is higher than that of the maximum temperature,which leads to decrease of DTR.The DTR is in a positive correlation with sunshine duration and in a negative correlation with precipitation in four seasons and the whole year.The effect of urbanization on the decrease of DTR is significant.