ABSTRACTS

Oral Session 10 | Thursday, October 6, 14:00–14:20 | Abstract 595

Remote sensing of atmosphere-ocean systems in the UV spectrum: Modeling absorption by phytoplankton

The NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission, scheduled for launch in 2024, will carry two instruments that measure ultraviolet (UV) radiance emerging from the top of the atmosphere: the Ocean Color Instrument (OCI) and the Spectro-Polarimeter for Planetary Exploration (SPEXone). OCI will provide single-view, hyperspectral radiometric data with a spectral resolution of 5 nm, whereas SPEXone will provide multiangle, multispectral polarimetric data with a degree of linear polarization accuracy of 0.3%. Together, these instruments will be the most advanced in NASA’s history for the combined observation of ocean color and atmospheric aerosols in the UV. In order to exploit the sensitivity to ocean color variations of observations in the UV, realistic models are required for variations in the UV scattering and absorption properties of oceanic constituents. We discuss a model for the UV absorption coefficient a ph of phytoplankton. This model is based on analyses of hundreds of a ph data sets, and it consists of 2 parts: (i) variations that are caused by changes in the Chlorophyll- a concentration [Chl]; and (ii) variations that are independent of changes in [Chl]. The former model part is similar to the heritage a ph model developed by Bricaud et al. (1998), except for including UV wavelengths. The latter model part aligns well with laboratory measurements of absorption by micosporine-like amino acids (MAAs). We demonstrate that the performance of our a ph model for UV wavelengths is similar to the performance of the Bricaud a ph model for visible wavelengths.

Jacek Chowdhary, Columbia University and NASA Goddard Institute for Space Studies, 0000-0002-5824-2163

Anna Wadhwa, NASA Goddard Institute for Space Studies

Matteo Ottaviani, NASA Goddard Institute for Space Studies and Terra Research Inc