POSTER Session 4

ACCURACY OF SEAHAWK-HAWKEYE OCEAN COLOR CUBESAT REMOTE SENSING REFLECTANCE PRODUCTS IN GLOBALLY DISTRIBUTED AQUATIC SITES

The Hawkeye sensor onboard SeaHawk, the first dedicated Ocean Color CubeSat, acquired ~9000 high spatial resolution (~120 m) images of open ocean, coastal, inland, and estuarine waters over a period of five years. With a spectral band configuration similar to the SeaWiFS sensor along with a modified 750 nm channel, HawkEye is capable of deriving water quality products, such as chlorophyll-a concentration (Chl-a), suspended sediments, or turbidity. As the accuracy of the derived products depends significantly on the remote sensing reflectance (Rrs) product after atmospheric correction, we aim to evaluate HawkEye Rrs against in situ data. We derived uncertainties from a match-up dataset (N=112) acquired over globally distributed aquatic sites, including AERONET-OC and coastal Georgia (USA). Statistical measures assessed included Median Symmetric Accuracy and Symmetric Signed Percentage Bias. When compared with the acquired in situ match-up data, HawkEye Rrs showed good agreement in green bands (490, 510, and 555 nm) with decreasing accuracy toward blue bands (412 and 443 nm), similar to the trend observed in traditional Ocean Color sensors, wherein blue bands have relatively larger differences in retrieved Rrs. We analyzed the impact of associated parameters, such as Chl-a, solar and viewing geometry, aerosol optical depth, and wind speed. Performance accuracy decreased in Chl-a waters (> 1mg/m^3), in consistent with ocean color Rrs assessments from other sensors in previous studies. Overall, HawkEye Rrs products show good retrieval accuracy and are suitable inputs for generating Ocean Color water quality products; however, atmospheric correction remains an important factor affecting accuracy.

Srinivas Kolluru, Skidaway Institute of Oceanography, University of Georgia, USA, [email protected], https://orcid.org/0000-0002-1619-1353

Sara Rivero Calle, Skidaway Institute of Oceanography, University of Georgia, USA, [email protected]

Philip J. Bresnahan, Center for Marine Science, University of North Carolina, USA, [email protected]

Susanne Kratzer, Stockholm University, Department of Ecology, Environment and Plant Sciences (DEEP), Sweden, [email protected]

Timothy S. Moore, Harbor Branch Oceanographic Institute, Florida Atlantic University, USA, [email protected]

Kohei Arai, Saga University, Japan, [email protected]

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