Pengwang Zhai - 613 Seminar Series

Passive satellite sensors measure the total radiance from the atmosphere-land or atmosphere-ocean systems, which has limited sensitivity to the vertical distribution of the particles in the atmospheric column. Passive aerosol remote sensing algorithms normally assume certain aerosol vertical profiles in order to perform meaningful retrievals. However, lidar measurements indicate that the aerosol vertical profiles are rarely non-variant. In this presentation I will try to answer to following questions regarding the aerosol vertical distribution assumption in the aerosol remote sensing algorithms: 1. Can a single-layer aerosol retrieval algorithms be used to retrieve aerosol properties for a multi-layer aerosol system? 2. What is the uncertainty introduced by this underlying assumption? 3. How to interpret the retrieved aerosol properties in terms of the true aerosol optical properties? An aerosol retrieval algorithm has been built which combines the Look Up Table (LUT) and least squares fitting methods. The algorithm is based on the multi-angle multi-wavelength polarized reflectance at the Top Of the Atmosphere (TOA) measured by the Research Scanning Polarimeter (RSP). The aerosol retrieval algorithm inherently assumes one layer of aerosols within the atmosphere. Synthetic polarized radiance data at the TOA have been created assuming either one or two layers of aerosols using the vector radiative transfer code based on successive order of scattering method. After validating the performance of the aerosol retrieval algorithm, the radiance data generated by two-layer aerosol systems are input to the retrieval algorithm to test the performance, uncertainty, and interpretation of the algorithm.