613 SEMINAR SERIES: W. Reed Espinosa

NASA/Climate & Radiation Laboratory

Climate & Radiation Laboratory Seminar Series
Wednesday, March 18, 2020
Building 33, Room H114

W. Reed Espinosa
NASA/Climate & Radiation Laboratory


Exploring the capabilities of synergistic passive and active remote sensing with a new aerosol retrieval testbed

Passive aerosol sensors composing the present generation of space-based instrumentation generally permit measurements spanning the majority of the shortwave spectrum, or observations at multiple viewing angles, but rarely both. Moreover, very few of these instruments possess sensitivity to polarization, and those that do lack the accuracy required to fully utilize this quantity. Another challenge for aerosol remote sensing has been the limited number of active sensors in orbit and their inability to constrain the LIDAR ratio—a parameter that can now be obtained directly with new, presently sub-orbital, technologies like High Spectral Resolution LIDAR (HSRL). In the next decade, a variety of satellites are expected to launch with sensors that will exceed these current measurement limitations. The increased information content in these new datasets is expected to drive significant improvements in aerosol remote sensing capabilities but, if this additional information is to be fully utilized, novel retrieval approaches will have to be developed and tested. In this work, surface parameterizations and aerosol models are used to simulate top of atmosphere polarized radiances and LIDAR profiles. Simulated noise is then added to these quantities to generate synthetic observations that are fed into the Generalized Retrieval of Aerosol and Surface Properties (GRASP). The resulting inversion products are then compared with the modeled inputs in order to obtain estimates of retrieval error for different instrument architectures. This new testbed can be used to explore various retrieval approaches as well as optimize future satellite instrumentation for sensitivity to the desired aerosol properties. In this talk, an analysis of the inversion capabilities of different instrument configurations under various observation scenarios will be presented, with an emphasis on the retrieval improvements afforded by polarization and the inclusion of LIDAR profiles. Special attention will be paid to cases in which the aerosol assumptions modeled by the retrieval diverge from the models used to generate the simulated scenes, including impacts stemming from uncertainties in particle morphology.


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