Title: Uncertainties in the retrieval of remote sensing reflectance from OC satellite observations

Speaker: Eder Herrera Estrella, NOAA EPP/MSI CESSRST-II Fellow at CUNY

Date: August 9, 20223

Time: 1:30 PM ET

Venue: Virtual

Meeting Link :  meet.google.com/xjr-zfee-aet

Phone Number
(‪US‬)‪+1 219-321-0478‬
PIN: ‪651 945 406#‬

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Abstract:

Uncertainties in retrieving remote sensing reflectance, Rrs, from Ocean Color (OC) satellite sensors have a substantial impact on the performance of algorithms, such as for the estimation of chlorophyll-a concentrations, and inherent optical properties (IOPs). The impact is highest in the blue bands, especially in coastal waters with low blue-band Rrs values. Sunlight propagates to the water and back to the top of the atmosphere (TOA) with the total radiance measured by the sensor capturing the radiances related to the instantaneous state of in-water conditions, sky, and sunlight reflected from the wind-roughened wave facets and light scattered on molecules and aerosols in the atmosphere. All these components are associated with uncertainties, which together with the effects of the instrument noise and uncertainties in aerosol models in the atmospheric correction process, contribute to uncertainties in the retrieved water-leaving radiance and remote sensing reflectance. Assuming that these uncertainties are mostly proportional to the corresponding radiances and taking advantage of the differences in the spectra of these radiances, we analyzed the contribution of the components above to the total Rrs uncertainties in the SNPP-VIIRS level 2products for multiple scenes in the open ocean and coastal waters at different spatial resolutions. Results are complemented by data from several AERONET-OC sites and the VIIRS validation/calibration cruises and showed that the Rayleigh component (molecular scattering and surface effects) is the main source of 𝑅𝑟𝑠 uncertainties for any water type followed by water variability, which has a bigger role in coastal areas, while the contributions of other components including aerosol scattering are usually smaller