The study investigated the effects of global direct radiative forcing due to carbonaceous aerosol on the climate in East Asia, using the CAM3 developed by NCAR. The results showed that carbonaceous aerosols cause nega...The study investigated the effects of global direct radiative forcing due to carbonaceous aerosol on the climate in East Asia, using the CAM3 developed by NCAR. The results showed that carbonaceous aerosols cause negative forcing at the top of the atmosphere （TOA） and surface under clear sky conditions, but positive forcing at the TOA and weak negative forcing at the surface under all sky conditions. Hence, clouds could change the sign of the direct radiative forcing at the TOA, and weaken the forcing at the surface. Carbonaceous aerosols have distinct effects on the summer climate in East Asia. In southern China and India, it caused the surface temperature to increase, but the total cloud cover and precipitation to decrease. However, the opposite effects are caused for most of northern China and Bangladesh. Given the changes in temperature, vertical velocity, and surface streamflow caused by carbonaceous aerosol in this simulation, carbonaceous aerosol could also induce summer precipitation to decrease in southern China but increase in northern China.展开更多
采用CERES SSFAqua MODIS Edition 2B/2C和CALIPSO卫星探测资料结合地面台站沙尘观测资料,通过对强沙尘天气过程中纯云区与沙尘云区大气层顶处辐射强迫值的对比分析,研究了我国华北地区沙尘气溶胶对云辐射强迫的影响.研究发现,2006年4...采用CERES SSFAqua MODIS Edition 2B/2C和CALIPSO卫星探测资料结合地面台站沙尘观测资料,通过对强沙尘天气过程中纯云区与沙尘云区大气层顶处辐射强迫值的对比分析,研究了我国华北地区沙尘气溶胶对云辐射强迫的影响.研究发现,2006年4月16日、5月16日、2007年3月30日3次过程沙尘云区大气层顶云的净辐射强迫绝对值比纯云区分别减小了7.1%,17.2%和3.1%,云的冷却效应受到不同程度抑制.纯云区与沙尘云区云的光学特性参量的对比分析结果表明,绝大部分沙尘云区的云粒径、云水路径和光学厚度值均比纯云区的要小.展开更多
本文应用WRF-Chem（Weather Research and Forecasting—Chemistry）模式研究中国东部地区气溶胶及其部分组分（硫酸盐、硝酸盐和黑碳气溶胶）在天气尺度下的辐射强迫和对地面气温的影响.5个无明显降水时间段（2006年8月23～25日、2008...本文应用WRF-Chem（Weather Research and Forecasting—Chemistry）模式研究中国东部地区气溶胶及其部分组分（硫酸盐、硝酸盐和黑碳气溶胶）在天气尺度下的辐射强迫和对地面气温的影响.5个无明显降水时间段（2006年8月23～25日、2008年11月10～12日、2008年12月16～18日、2009年1月15～17日和2009年4月27～29日）的模拟显示,气溶胶浓度呈现显著的白天低,夜间高的日变化特征,且北方区域（29.8°～42.6°N,110.2°～120.3°E）平均PM2.5近地面浓度（40～80μg m-3）高于南方区域（22.3°～29.9°N,109.7°～120.2°E,30～47 μg m-3）.气溶胶对地面2m温度（地面气温）有明显的降温效果,在早上08：00（北京时,下同）和下午17：00左右最为显著,最高可降低约0.2～1 K,同时气溶胶的参与改善了模式对地面气温的模拟.本文还通过对2006年8月23～25日一次个例的模拟,定量分析了气溶胶及其部分组分（硫酸盐、硝酸盐和黑碳气溶胶）的总天气效应（直接效应＋间接效应）、直接效应和间接效应分别对到达地面的短波辐射和地面气温的影响.北方区域平均气溶胶直接效应所造成的短波辐射强迫要高于南方区域,分别为-11.3 Wm^-2和-5.8Wm^-2,导致地面气温分别降低了0.074 K和0.039 K.南方区域平均气溶胶间接效应所产的短波辐射强迫高于北方区域,分别为-14.4 W m^-2和-12.4W m^-2,引起的地面气温的改变分别为-0.094K和-0.035K.对于气溶胶组分,硫酸盐气溶胶的直接效应和间接效应的作用相当,其总效应在北方和南方区域平均短波辐射强迫分别为-7.0 Wm^-2和-10.5 Wm^-2,对地面气温的影响为-0.062 K和-0.074 K,而硝酸盐气溶胶的作用略小.黑碳气溶胶使得北方和南方区域平均到达地表的太阳短波辐射分别减少了6.5 Wm^-2和5.8 W m^-2,而地表气温则分别增加了0.053 K和0.017 K,相比于间接效应,黑碳气溶胶的直接效应的影响更加显著.展开更多
Tropospheric ozone（O3） and aerosols are major air pollutants in the atmosphere. They have also made significant contributions to radiative forcing of climate since preindustrial times. With its rapid economic develo...Tropospheric ozone（O3） and aerosols are major air pollutants in the atmosphere. They have also made significant contributions to radiative forcing of climate since preindustrial times. With its rapid economic development, concentrations of air pollutants are relatively high in China; hence, quantifying the role of air pollutants in China in regional climate change is especially important. This review summarizes existing knowledge with regard to impacts of air pollutants on climate change in China and defines critical gaps needed to reduce the associated uncertainties. Measured monthly, seasonal, and annual mean surface-layer concentrations of O3 and aerosols over China are compiled in this work, with the aim to show the magnitude of concentrations of O3 and aerosols over China and to provide datasets for evaluation of model results in future studies. Ground-based and satellite measurements of O3 column burden and aerosol optical properties, as well as model estimates of radiative forcing by tropospheric O3 and aerosols are summarized. We also review regional and global modeling studies that have investigated climate change driven by tropospheric O3and/or aerosols in China; the predicted sign and magnitude of the responses in temperature and precipitation to O3/aerosol forcings are presented. Based on this review, key priorities for future research on the climatic effects of air pollutants in China are highlighted.展开更多
基金supported by Na-tional Basic Research Program of China (Grant No.2006CB403707)the public Meteorology Special Foundation of MOST (Grant No. GYHY200706036)the National Key Technology R & D Program (Grant No.2007BAC03A0)
文摘The study investigated the effects of global direct radiative forcing due to carbonaceous aerosol on the climate in East Asia, using the CAM3 developed by NCAR. The results showed that carbonaceous aerosols cause negative forcing at the top of the atmosphere （TOA） and surface under clear sky conditions, but positive forcing at the TOA and weak negative forcing at the surface under all sky conditions. Hence, clouds could change the sign of the direct radiative forcing at the TOA, and weaken the forcing at the surface. Carbonaceous aerosols have distinct effects on the summer climate in East Asia. In southern China and India, it caused the surface temperature to increase, but the total cloud cover and precipitation to decrease. However, the opposite effects are caused for most of northern China and Bangladesh. Given the changes in temperature, vertical velocity, and surface streamflow caused by carbonaceous aerosol in this simulation, carbonaceous aerosol could also induce summer precipitation to decrease in southern China but increase in northern China.
文摘采用CERES SSFAqua MODIS Edition 2B/2C和CALIPSO卫星探测资料结合地面台站沙尘观测资料,通过对强沙尘天气过程中纯云区与沙尘云区大气层顶处辐射强迫值的对比分析,研究了我国华北地区沙尘气溶胶对云辐射强迫的影响.研究发现,2006年4月16日、5月16日、2007年3月30日3次过程沙尘云区大气层顶云的净辐射强迫绝对值比纯云区分别减小了7.1%,17.2%和3.1%,云的冷却效应受到不同程度抑制.纯云区与沙尘云区云的光学特性参量的对比分析结果表明,绝大部分沙尘云区的云粒径、云水路径和光学厚度值均比纯云区的要小.
基金supported by the National Basic Research Program of China (Grant No. 2014CB441202)the Chinese Academy of Sciences Strategic Priority Research Program (Grant No. XDA05100503)+1 种基金the National Natural Science Foundation of China (Grant Nos. 41475137 and 41321064)Special Funding in Atmospheric Science (Grant No. GYHY200906020)
文摘Tropospheric ozone（O3） and aerosols are major air pollutants in the atmosphere. They have also made significant contributions to radiative forcing of climate since preindustrial times. With its rapid economic development, concentrations of air pollutants are relatively high in China; hence, quantifying the role of air pollutants in China in regional climate change is especially important. This review summarizes existing knowledge with regard to impacts of air pollutants on climate change in China and defines critical gaps needed to reduce the associated uncertainties. Measured monthly, seasonal, and annual mean surface-layer concentrations of O3 and aerosols over China are compiled in this work, with the aim to show the magnitude of concentrations of O3 and aerosols over China and to provide datasets for evaluation of model results in future studies. Ground-based and satellite measurements of O3 column burden and aerosol optical properties, as well as model estimates of radiative forcing by tropospheric O3 and aerosols are summarized. We also review regional and global modeling studies that have investigated climate change driven by tropospheric O3and/or aerosols in China; the predicted sign and magnitude of the responses in temperature and precipitation to O3/aerosol forcings are presented. Based on this review, key priorities for future research on the climatic effects of air pollutants in China are highlighted.
