本文通过中层大气高空冰探测器(Aeronomy of Ice in the Mesosphere,AIM)卫星的仪器载荷——用于云成像和粒子实验的探测器(Cloud Imaging and Particle Size,CIPS)和用于冰晶实验的太阳掩星探测器(Solar Occultation for Ice Experimen...本文通过中层大气高空冰探测器(Aeronomy of Ice in the Mesosphere,AIM)卫星的仪器载荷——用于云成像和粒子实验的探测器(Cloud Imaging and Particle Size,CIPS)和用于冰晶实验的太阳掩星探测器(Solar Occultation for Ice Experiment,SOFIE)在2007—2014年间南、北半球的观测数据,分析了2007—2014年间夜光云的反照率、冰水含量(ice water content,IWC)、每日发生率及中层顶温度在南、北半球的变化趋势,讨论了夜光云发生位置和年变化,并且对夜光云反照率、中层顶温度和IWC的相关性进行了分析。结果表明:南、北半球夜光云主要发生在80°~85°纬度范围内,与南半球相比,北半球夜光云反照率持续时间更长、年波动更小、IWC更高且每日发生率更高,而南半球90°W~150°W位置的反照率总是较低;南、北半球夜光云反照率和IWC均与中层顶温度之间存在负相关关系,但反照率和冰水含量相关性表现不明显。本文的研究结果为夜光云作为中间层大气变化的敏感指标提供了量化依据;同时,南、北半球夜光云的差异特性有助于改进气候模型,对理解长期气候变化中的半球不对称响应具有参考意义。展开更多
To quantitatively understand the dust aerosol effects on climate change, we calculated the global dis-tribution of direct radiative forcing due to dust aerosol under clear and cloudy skies in both winter and summer, b...To quantitatively understand the dust aerosol effects on climate change, we calculated the global dis-tribution of direct radiative forcing due to dust aerosol under clear and cloudy skies in both winter and summer, by using an improved radiative transfer model and the global distribution of dust mass concentra-tion given by GADS （Global Aerosol Data Set）. The results show that the global means of the solar forcing due to dust aerosol at the tropopause for winter and summer are -0.48 and -0.50 W m-2, respectively; the corresponding values for the longwave forcing due to dust are 0.11 and 0.09 W m-2, respectively. At the surface, the global means of the solar forcing clue to dust are -1.36 W m-2 for winter and -1.56 W m-2 for summer, whereas the corresponding values for the longwave forcing are 0.27 and 0.23 W m-2, respectively. This work points out that the absolute values of the solar forcing due to dust aerosol at both the tropopause and surface increase linearly with the cosine of solar zenith angle and surface albedo. The solar zenith angle influences both the strength and distribution of the solar forcing greatly. Clouds exert great effects on the direct radiative forcing of dust, depending on many factors including cloud cover, cloud height, cloud water path, surface albedo, solar zenith angle, etc. The effects of low clouds and middle clouds are larger than those of high clouds. The existence of clouds reduces the longwave radiative forcing at the tropopause, where the influences of low clouds are the most obvious. Therefore, the impacts of clouds should not be ignored when estimating the direct radiative forcing due to dust aerosol.展开更多
文摘本文通过中层大气高空冰探测器(Aeronomy of Ice in the Mesosphere,AIM)卫星的仪器载荷——用于云成像和粒子实验的探测器(Cloud Imaging and Particle Size,CIPS)和用于冰晶实验的太阳掩星探测器(Solar Occultation for Ice Experiment,SOFIE)在2007—2014年间南、北半球的观测数据,分析了2007—2014年间夜光云的反照率、冰水含量(ice water content,IWC)、每日发生率及中层顶温度在南、北半球的变化趋势,讨论了夜光云发生位置和年变化,并且对夜光云反照率、中层顶温度和IWC的相关性进行了分析。结果表明:南、北半球夜光云主要发生在80°~85°纬度范围内,与南半球相比,北半球夜光云反照率持续时间更长、年波动更小、IWC更高且每日发生率更高,而南半球90°W~150°W位置的反照率总是较低;南、北半球夜光云反照率和IWC均与中层顶温度之间存在负相关关系,但反照率和冰水含量相关性表现不明显。本文的研究结果为夜光云作为中间层大气变化的敏感指标提供了量化依据;同时,南、北半球夜光云的差异特性有助于改进气候模型,对理解长期气候变化中的半球不对称响应具有参考意义。
基金Supported by the National Key Technology R&D Program under Grant No.2008BAC40B02the National Basic Research Program of China under Grant No.2011CB403405the Special Fund for Public Welfare (meteorology) by the Ministry of Science and Technology under Grant No.GYHY200706036
文摘To quantitatively understand the dust aerosol effects on climate change, we calculated the global dis-tribution of direct radiative forcing due to dust aerosol under clear and cloudy skies in both winter and summer, by using an improved radiative transfer model and the global distribution of dust mass concentra-tion given by GADS （Global Aerosol Data Set）. The results show that the global means of the solar forcing due to dust aerosol at the tropopause for winter and summer are -0.48 and -0.50 W m-2, respectively; the corresponding values for the longwave forcing due to dust are 0.11 and 0.09 W m-2, respectively. At the surface, the global means of the solar forcing clue to dust are -1.36 W m-2 for winter and -1.56 W m-2 for summer, whereas the corresponding values for the longwave forcing are 0.27 and 0.23 W m-2, respectively. This work points out that the absolute values of the solar forcing due to dust aerosol at both the tropopause and surface increase linearly with the cosine of solar zenith angle and surface albedo. The solar zenith angle influences both the strength and distribution of the solar forcing greatly. Clouds exert great effects on the direct radiative forcing of dust, depending on many factors including cloud cover, cloud height, cloud water path, surface albedo, solar zenith angle, etc. The effects of low clouds and middle clouds are larger than those of high clouds. The existence of clouds reduces the longwave radiative forcing at the tropopause, where the influences of low clouds are the most obvious. Therefore, the impacts of clouds should not be ignored when estimating the direct radiative forcing due to dust aerosol.
