上海地区地气温差变化特征及影响因子初步分析

Variation characteristics of Shanghai ground-air temperature difference and its influence factors

地气温差作为计算地面感热通量的主要指标,对地表热量平衡有重要影响。利用1961—2015年上海地区9个气象台(站)的地表温度、地面气温、风速、降水、日照时数、蒸发量、相对湿度观测资料,对上海地区地气温差变化特征及其影响因素进行了分析。结果表明:(1)上海地区地气温差在夏季最大,冬季最小,各个季节地气温差均呈现出从中心城区向郊区递增的特征。(2)受地面气温上升速率快于地表温度影响,上海地区年平均地气温差总体呈缓慢减小趋势,其中夏季最为明显,中心城区和近郊站点减少趋势最为显著。上海中心城区热岛强度绝对值呈现增大趋势,但其对地气温差变化相对贡献率呈现出降低趋势。(3)影响上海地区夏季和秋季地气温差的显著环境因子为日照和降水,春季的显著影响因子为降水,冬季的显著影响因子为风速。该结论对科学认识气候变化背景下城市热环境的变化规律有重要意义,也为保护和改善城市生态环境提供了科学依据。

As the main index of ground sensible heat flux,the ground-air temperature difference（GATD） is the most important component in the surface heat balance. Observation data of ground temperature, surface air temperature,wind speed, precipitation, sunshine hours, evaporation and relative hunfidity, which were obtained from 9 meteorological stations in Shanghai during 1961~015 ,were used to analysis the changing characteristics of GATD and its impact factors. The results show that ： （ 1 ） GATD in Shanghai is biggest in summer and nfinimum in winter,and shows the characteristics of increasing from the center of the city to the suburbs in all seasons. （2） Due to the air temperature＇s faster rising rate than ground temperature, the annual average GATD is slowly decreased in Shanghai, with the most obvious decreasing season in summer and the most significantly region in re＇ban and subm＇ban alias. The absolute value of the re＇ban heat island intensity of Shanghai showed an increasing trend, but its relative contribution to the variation of GATD showed a decreasing trend. （3）In summer and autumn the significant environmental factors affecting GATD are sunshine hours and precipitation, in spring is precipitation and in winter is average wind speed. The conclusions obtained in this paper are important to the understanding of changing characteristics of urban thermal environment under the background of climate change, and also provide a scientific reference to the protection and improvement of urban ecological environment.