全球气溶胶三维输送特征及其气候效应的卫星遥感研究

Aerosol-cloud interaction remains one of the key uncertainties in the current climate models. Over cloudy sky, especially under the condition that aerosol transports above the clouds, the aerosol has close interactions with cloud and can also introduce uncertainties in the passive remote sensing of the micro- and macro properties of clouds. Current knowledge about the long-range transport of aerosol is sill limited, especially for aerosol above cloud. The reason could be the limited measurement of this kind of aerosol over global scale. Moreover, the complex aerosol mixture over east-Asia region is still poorly considered in the remote sensing methodology studies. This program will focus on improving the retrieval of elevated aerosol layer during long-range transport with satellite measurements. By combining satellite Lidar multi-channel observations, ground-base observations, model reanalysis product and radiative transfer model simulations, the detection of both dense and thin aerosol layer and retrieval of complex aerosol mixture will be improved for both day- and night-time measurements. Reliable identification and retrieval methodologies for elevated aerosol will be developed, to build a new global multi-year long-range transport aerosol dataset. Furthermore, this new datasets will be used to evaluate the aerosol radiative effects and aerosol-cloud interactions during long-range transport, and to improve the passive remote sensing of cloud micro- and macro properties over east-Asia regions when aerosol above cloud exists. This study will provide promising remote sensing measurement results for further evaluating and improving the performance of climate models in aerosol-cloud related processes.

气溶胶及其与云的相互作用仍然是目前气候模式最重要的不确定性因子之一。气溶胶长途输送过程中与云存在着较为密切的相互作用,尤其气溶胶在云上传输会对被动反演云宏微观特征造成较大的影响。目前对长途输送气溶胶尤其云上气溶胶的观测和认识仍存在局限性,卫星反演中对东亚区域复杂混合型污染物的情况考虑也较少。本项目将侧重于改进卫星遥感对高于地面的长途输送气溶胶的探测和反演。通过结合星载激光雷达多通道观测、星载被动遥感、地基观测、模式再分析资料、辐射传输计算等,改进星载激光雷达在气溶胶的检测以及混合型气溶胶反演等方面的不足,发展可靠可信的远程输送气溶胶识别和反演算法,建立新的全球长途输送气溶胶光学特性三维分布的多年卫星主动反演数据集。进而评估长途输送气溶胶尤其是云上气溶胶的辐射效应及与云相互作用,订正其对东亚区域云宏微观特征被动反演的影响。本项目的研究也可以为进一步评估和改进气候模式模拟提供更多的观测依据。

气溶胶长途输送尤其是气溶胶在云上传输时对低云的宏微观特性存在重要影响，然而长途输送气溶胶的主被动遥感观测方法存在局限性，限制了对其辐射效应的认识。本项目对现有星载激光雷达气溶胶遥感算法进行了针对性改进，着重建立了星载激光雷达昼夜噪声一致性抑制算法、分子消光订正算法、云掩码识别订正算法、东亚复合型气溶胶消光吸湿增长模型和多通道联合气溶胶识别反演算法；在新算法的基础上建立了更精细准确的全球长途输送气溶胶多年卫星遥感数据集，获得了昼夜反演结果更为一致、时空分布更为合理的云上气溶胶全球分布特征；对比研究了不同气溶胶条件下、不同云相态情况下低层云特征，量化了气溶胶对于低云云水及降水概率的影响，并分析讨论了云上气溶胶与云的相互作用，阐明了从源区到长途输送区域云上气溶胶-云相互作用机制的差异，建立了不同类型云上气溶胶与低云粒径的反演关系，可应用于改进主被动遥感云微物理特征。本项目的研究增进了对全球传输型气溶胶特性时空分布及其与云相互作用的了解，可为进一步评估和改进气候模式提供更多观测和科学依据。