利用CALIPSO资料研究极地平流层云对卫星监测臭氧损耗精度的影响

Polar stratospheric clouds(PSCs) play a very important role in polar ozone depletion, because heterogeous reactions, which sharply reduce the ozone amount in atmosphere,in particular, the content of chlorine and nitric compounds actively participating in the destruction of ozone, occur on their surfaces. PSCs also affect satellite-based ozone remote sensing, because these ozone retrieval algorithms now in operation consider effects of tropospheric clouds and aerosol but neglecting stratospheric clouds' effect. On the basis of measurements from ground-based instruments, balloon-borne ozonesondes，and simultaneous measurements of aerosol and ozone concentrations during aircraft flights in the Antarctic and Arctic regions, the appearance of PSCs are frequently associated with false ozone reduction derived from solar backscattered ultraviolet albedo data of satellite ozone monitoring instruments. In this project, we will study the effect of PSCs on the solar backscattered radiance measurements of satellite ozone remote sensing instruments, by combining radiative transfer calculations with the observed PSCs data from the CALIPSO (Cloud-Aerosol-Lidar and Infrared Pathfinder Satellite Observations) satellite and ozone data from FY-3 SBUS/TOU (Backscatter Ultraviolet Sounder/ Total Ozone Unit) and Aura OMI (Ozone Monitoring Instrument). The radiative transfer calculations will be implemented with the SBURFCSS (Solar Backscattered Ultraviolet Radiance Forward Calculation Simulating System), which was developed by us during the development of the FY-3 ozone vertical profile and total ozone retrieval algorithms. The output of simulated radiance measuremnts from the SBURFCSS will be used as input to the OZPTOPGSS (Ozone Vertical Profile and Total Ozone Products Generating Simulation System) and ozone profiles and total ozone data are derived. The OZPTOPGSS was built by us in develping the FY-3 satellite ozone retrieval algorithms. Effects of PSCs on satellite-based ozone monitoring are evaluated by comparing the newly retrieved data with ozone surface observation data from these WOUDC (World Ozone and Ultraviolet Radiation Data Centre) stations located at the Antarctic and Arctic regions. We will then establish a correcting method for satellite-based monitoring ozone depletion data, and give the actual ozone change data in polar regions based on these studies.

极地平流层云PSCs(Polar Stratospheric Clouds)为臭氧损耗非均相化学反应提供表面，在极地臭氧损耗中发挥重要作用。PSCs也对卫星臭氧遥感产生影响，但现有卫星臭氧反演算法只考虑了对流层云和气溶胶的影响。大量的地基与卫星同步观测表明，PSCs的存在往往导致卫星观测数据反演错误，从而使极地臭氧损耗监测数据偏离真实值。本项目利用CALIPSO PSCs实测资料，结合FY-3 SBUS/TOU以及Aura OMI观测数据，共同组成观测参数，输入建立的太阳紫外后向散射辐射传输正演仿真系统，计算PSCs对卫星载荷辐射观测值的影响；将正演仿真计算结果，输入建立的臭氧垂直廓线和臭氧总量产品生成仿真系统，开展反演计算，通过与极地地基台站臭氧观测资料比较，研究PSCs对卫星遥感臭氧产品精度的影响。在此基础上，建立PSCs覆盖区域卫星遥感臭氧产品订正方法，给出极地臭氧损耗真实变化数据。

项目的背景是针对每年春季北极臭氧损耗期间极地平流层云对卫星卫星臭氧遥感反演计算产生的影响，而现有卫星臭氧反演算法只考虑了对流层云和气溶胶的影响，对平流层云的影响作用无法进行评估的状况，本项目利用CALIPSO PSCs观测资料，应用风云三号卫星建立的太阳紫外后向散射辐射传输正演仿真系统和臭氧产品反演生成仿真系统，开展PSCs对卫星观测数据和反演结果的仿真计算，定量评估PSCs对卫星遥感臭氧产品精度的影响。还利用卫星遥感对北极地区大气臭氧变化、臭氧与大气相关关系等进行探讨。.利用2012年春季CALIPSO PSCs观测数据输入太阳紫外辐射正演仿真系统，通过正演仿真计算，表明PSCs的存在导致紫外通道波长在292nm以下的通道辐射值增强4-6%，波长在292nm以上的通道辐射值增强5-10%不等的水平。通过将正演仿真计算结果输入卫星臭氧反演仿真系统开展对比反演计算，结果表明，由于PSCs的存在对卫星辐射值的改变，导致臭氧总量反演结果产生4-6DU的差异。模拟反演计算还表明，PSCs对臭氧垂直廓线的影响主要在对流层顶以上的高度层，影响幅度在1-3DU不等的水平。该研究结果表明，极地平流层云PSCs的存在确实对基于紫外后向散射技术的卫星臭氧遥感精度产生影响。.利用卫星遥感资料监测2015年12月末的北极地表爆发性增温事件，12月29日北极点附近地区臭氧比12月平均值减少60DU，这些减少主要发生在400-5hPa的高层。表明每年北极冬季受北大西洋暖流等动力输送的影响，可以导致臭氧的急剧变化，并进一步影响东亚和北美等地冬季气候。.考察了北极地区大气臭氧与温度相关关系时空变化特征。平流层冬季和夏季大气温度与臭氧呈较强的正相关性，对流层春季和秋季大气温度与臭氧主要呈负相关性。北极臭氧与大气温度相关关系在不同季节存在显著的割裂性：在下平流层，冬季和夏季呈现正相关性，春季和秋季则在多数地区不相关，少数地区呈弱正相关或负相关性；在对流层，春季和秋季呈负相关性，冬季和夏季在超过1/3的地区呈现无关性，其它地区呈现弱负相关性。这与中低纬度地区存在根本性差别。