Impact of Direct Radiative Forcing of Anthropogenic Aerosols on Diurnal Temperature Range in January in Eastern China  

作　　者：CHANG Wen-Yuan LIAO Hong 

机构地区：[1]State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry （LAPC）, Institute of Atmospheric Physics,Chinese Academy of Sciences, Beijing 100029, China

出　　处：《Atmospheric and Oceanic Science Letters》2011年第6期356-362,共7页大气和海洋科学快报（英文版）

基　　金：supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant Nos.KZCX2-YW-Q11-03 and KZCX2-YW-Q1-02);the National Natural Science Foundation of China(Grant No.40825016);the China Meteorological Administration for the Special Project of Meteorological Sector(Grant No.GYHY200906020)

摘　　要：This study investigates the changes in January diurnal temperature range(DTR) in China during 1961-2000.The observed DTR changes during 1981-2000 relative to 1961-80 are first analyzed based on the daily temperature data at 546 weather stations.These observed DTR changes are classified into six cases depending on the changes in daily maximum and minimum temperatures,and then the occurrence frequency and magnitude of DTR change in each case are presented.Three transient simulations are then performed to understand the impact of greenhouse gases(GHGs) and aerosol direct forcing on DTR change:one without anthropogenic radiative forcing,one with anthropogenic GHGs,and another one with the combined forcing of GHGs and five species of anthropogenic aerosols.The predicted daily DTR changes during the years 1981-2000 are also classified into six cases and are compared with the observations.Results show that the previously proposed reason for DTR reduction,a stronger nocturnal warming than a daytime warming,explains only 19.8%of the observed DTR reduction days.DTR reductions are found to generally occur in northeastern China,coinciding with significant regional warming.The simulation with GHG forcing alone reproduces this type of DTR reduction with an occurrence frequency of 32.9%,which is larger than the observed value.Aerosol direct forcing reduces DTR mainly by daytime cooling.Consideration of aerosol cooling improves the simulation of occurrence frequencies of different types of DTR changes as compared to the simulation with GHGs alone,but it cannot improve the prediction of the magnitude of DTR changes.This study investigates the changes in January diurnal temperature range （DTR） in China during 1961- 2000. The observed DTR changes during 1981-2000 relative to 1961-80 are first analyzed based on the daily temperature data at 546 weather stations. These observed DTR changes are classified into six cases depending on the changes in daily maximum and minimum temperatures, and then the occurrence frequency and magnitude of DTR change in each case are presented. Three transient simulations are then performed to understand the impact of greenhouse gases （GHGs） and aerosol direct forcing on DTR change： one without anthropogenic radiative forcing, one with anthropogenic GHGs, and another one with the combined forcing of GHGs and five species of anthropogenic aerosols. The predicted daily DTR changes during the years 1981-2000 are also classified into six cases and are compared with the observations. Results show that the previously proposed reason for DTR reduction, a stronger nocturnal warming than a daytime warming, explains only 19.8% of the observed DTR reduction days. DTR reduc- tions are found to generally occur in northeastern China, coinciding with significant regional warming. The simu- lation with GHG forcing alone reproduces this type of DTR reduction with an occurrence frequency of 32.9%, which is larger than the observed value. Aerosol direct forcing reduces DTR mainly by daytime cooling. Consideration of aerosol cooling improves the simulation of occurrence frequencies of different types of DTR changes as compared to the simulation with GHGs alone, but it cannot improve the prediction of the magnitude of DTR changes.

关 键 词：diurnal temperature range greenhouse gases anthropogenic aerosols aerosol direct effect 

分 类 号：P422[天文地球—大气科学及气象学] P618.130.2