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1、北极地区气溶胶-云-辐射相互作用,赵传峰北京师范大学2017年11月14日国防科技大学,Aerosol,clouds and their interaction play crucial roles to both energy balance and hydrological cycle,and thus climate change,Energy Balance,Hydrological Cycle,Motivation,Wild et al.2012,Climate Dynamics,NASA,Motivation,The Arctic is warming at a double ra
2、te of global mean in recent century,cuasing significant impacts to society.For Arctic fast warming,do aerosols from mid-latitudes play a contributing role?,Smith et al.2015,Nature Climate Change,30%reduction of ice coverage in the Arctic,1.云微观特征,多个云微观特征产品的比对分析,Zhao et al.2012,JGR,各个云产品之间有着非常显著的差异,云反
3、演不确定性的量化/云产品评估,Zhao et al.2014,JGR,集合扰动方法,MICROBASE,发现：云水含量误差主要源于观测数据误差；云水有效半径误差主要源于所用假设；云冰特征误差主要源于所用经验公式参数。,Thin Stratus Cloud Retrieval Algorithm,:1-2re:effective radius:geometric optical depthN:particle concentrationLWP:liquid water path,Zhao and Garrett,AMS,2006Garrett and Zhao,AMT,2013,CO2,Stra
4、t.O3,Atmos.window,Cloud Microwindows,Retrieval bands,云的微观特征：基于AERI的薄云特征反演方法,用臭氧波段云传输系数代替太阳短波波段云传输系数，反演方法不再依赖于太阳，可以昼夜连续测量云特性。,Garrett and Zhao 2013,AMT,与飞机观测比对分析,My retrievals are comparabble to solar-based retrievals by Dong and Mace 2003,(Dong and Mace 2003),与基于太阳辐射反演方法比对分析,2.北极云微观特征对气溶胶的高敏感性,The i
5、ncreasing amount of aerosols could result in more cloud condensation nuclei,more cloud droplets,smaller cloud droplet effective radius,and higher cloud abldeo(Twomey effect);also longer lifetime;.,气溶胶-云相互作用结构图,IPCC 2007,气溶胶对云微观结构的影响-北极云微观特征对气溶胶的强敏感性,Garrett,Zhao et al.2004,GRL,0.13-0.19,气溶胶对云微观结构的影响
6、-气溶胶影响,N:(CAM5)FIE:0.07-0.14,Aerosol Light Scattering(Obs)0.11-0.19,CCN:(CAM5)FIE:0.10-0.25,Zhao et al.2012,Zhao,et al.2012，GRL,3.气溶胶-云相互作用的间接辐射效应,Even more(0.5-0.6 in winter)found by ice station(Walsh and Chapman 1998,北极Haze,Quinn et al.2007,红外云辐射对云水含量和云滴有效半径的敏感性,Garrett et al.2002,气溶胶第一间接辐射效应,气溶胶增
7、多-云滴数目增多、云滴有效半径减小(第一间接作用)-云长波辐射系数增加-北极气候变暖,Garrett and Zhao,2006,Nature,气溶胶第一间接辐射效应,北极冬春季节，气溶胶污染会通过改变云特征导致辐射增加3-5 W/m2或地面增温2-3 K（用云量50%权重平均，地面增温1-1.6 K），增温效应堪比温室气体。,Garrett and Zhao,2006,Nature,(Equal Contribution from Both Authors),北极层云主导多数云量Full resolution image(30 m x 300 m),薄云云量和长波辐射系数,云-辐射反馈,No
8、minally clean,Nominally polluted,LES Simulations Indicate Faster Development of Arctic Stratus Clouds with Small re,Garrett et al.2011,气溶胶间接气候效应的季节分布规律,净辐射效应夏季冷却，其余季节增暖；冬春的强增暖效应促进了冰雪融化，后续反馈进一步使气候增暖。,Zhao et al.2015,GRL,温度季节分布在清洁和污染情况下的差异,统计上来说，干净和污染情景下云底温度没有显著性差别,4.云降水对气溶胶的冲刷作用,气溶胶浓度的影响因子,气溶胶浓度：-源项(
9、Heintzenberg and Larssen,1983,Raatz and Shaw,1984,Stohl 2006)决定于中纬度气溶胶传输的北极的传输效率和中纬度的污染排放量。-汇项(Shaw,1995),-Mixing（混合项）：夏季混合效率仅有冬季的一半(Stohl,2006)-Dry deposition（干沉降）：由于地面缺乏植被，北极干沉降非常缓慢-Wet deposition（湿沉降）：降水存在时，湿沉降是最有效的去除机制 Barrow站点观测表明日均降水量为1mm(Zhao and Garrett,2008),可溶性气溶胶在北极夏天被雨水完全冲刷的典型时间大约为1小时,气溶
10、胶冲刷与长距离传输的相对贡献,Garrett et al.,2010,Tellus B,Summary,Cloud properties generally have large uncertainties,more accurate cloud retrieval algorithm is necessary.An optimal retrieval algorithm which can obtain cloud properties day and night was developed.The seasonal distribution of Arcitc aerosol is ass
11、ociated with the impacts of long-range transport efficiency from mid-latitudes and precipitation scavenging efficiency.The sensitivity of clouds to aerosols is large in the Arctic.Aerosol first indirect effect play a strong warming effect(3-5 W/m2)in the Arctic in winter and spring；For the whole aerosol warming effect(8-10W/m2)in winter and spring,60%caused by FIE,40%by other feedbacks.,谢谢各位聆听！敬请批评指正！,
