Effect of model errors in ambient air humidity on the aerosol optical depth obtained via aerosol hygroscopicity in eastern China in the Atmospheric Chemistry and Climate Model Intercomparison Project datasets  

作　　者：CHANG Wenyuan 

机构地区：[1]State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences

出　　处：《Atmospheric and Oceanic Science Letters》2019年第3期162-169,共8页大气和海洋科学快报（英文版）

基　　金：jointly supported by the National Key Research and Development Program of China [grant number2016YFE0201400];the Basic Research Program of the State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences [grant number 7-082999]

摘　　要：This analysis of the multi-model aerosol optical depth (AOD) in eastern China using the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) datasets shows that the global models underestimate the AOD by 33% and 44% in southern and northern China, respectively, and decrease the relative humidity (RH) of the air in the surface layer to 71%–80%, which is less than the RH of 77%–92% in reanalysis meteorological datasets. This indicates that the low biases in the RH partially account for the errors in the AOD. The AOD is recalculated based on the model aerosol concentrations and the reanalysis humidity data. Improving the mean value of the RH increases the multi-model annual mean AOD by 45% in southern China and by 33% in June–August in northern China. This method of improving the AOD is successful in most of the ACCMIP models, but it is unlikely to be successful in GISS-E2-R, in which the plot of its AOD efficiency against RH strongly deviates from the rest of the models. The effect of the improvement in the modeled RH on the AOD depends on the concentration of aerosols. The shape error in the frequency distribution of the RH is likely to be more important than the error in the mean value of the RH, but this requires further research.当前全球气候模式普遍低估中国东部气溶胶光学厚度(AOD)。本文表明,模式低估中国东部地表大气相对湿度是AOD低估的原因之一。研究基于国际大气化学气候模式比较计划的干气溶胶质量浓度结果,用再分析湿度数据替换模拟湿度以计算AOD变化。结果表明,替换后我国大气相对湿度增加,多模式平均的华南年均AOD因此增长45%,华北6-8月AOD增长33%。不同模式采用相似的硫酸盐吸湿增长曲线。相对湿度低估对AOD模拟影响程度主要受吸湿颗粒质量浓度和相对湿度概率分布影响,该结论有助于解释我国AOD模拟误差。

关 键 词：Atmospheric Chemistry and Climate Model Intercomparison Project aerosol optical depth efficiency relative humidity aerosol hygroscopicity 

分 类 号：P[天文地球]