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Frouin RJ, Franz BA, Ibrahim A, Knobelspiesse K, Ahmad Z, Cairns B, Chowdhary J, Dierssen HM, Tan J, Dubovik O, Huang X, Davis AB, Kalashnikova O, Thompson DR, Remer LA, Boss E, Coddington O, Deschamps PY, Gao BC, Gross L, Hasekamp O, Omar A, Pelletier B, Ramon D, Steinmetz F, Zhai PW. Atmospheric Correction of Satellite Ocean-Color Imagery During the PACE Era. FRONTIERS IN EARTH SCIENCE 2019; 7:10.3389/feart.2019.00145. [PMID: 32440515 PMCID: PMC7241613 DOI: 10.3389/feart.2019.00145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission will carry into space the Ocean Color Instrument (OCI), a spectrometer measuring at 5nm spectral resolution in the ultraviolet (UV) to near infrared (NIR) with additional spectral bands in the shortwave infrared (SWIR), and two multi-angle polarimeters that will overlap the OCI spectral range and spatial coverage, i. e., the Spectrometer for Planetary Exploration (SPEXone) and the Hyper-Angular Rainbow Polarimeter (HARP2). These instruments, especially when used in synergy, have great potential for improving estimates of water reflectance in the post Earth Observing System (EOS) era. Extending the top-of-atmosphere (TOA) observations to the UV, where aerosol absorption is effective, adding spectral bands in the SWIR, where even the most turbid waters are black and sensitivity to the aerosol coarse mode is higher than at shorter wavelengths, and measuring in the oxygen A-band to estimate aerosol altitude will enable greater accuracy in atmospheric correction for ocean color science. The multi-angular and polarized measurements, sensitive to aerosol properties (e.g., size distribution, index of refraction), can further help to identify or constrain the aerosol model, or to retrieve directly water reflectance. Algorithms that exploit the new capabilities are presented, and their ability to improve accuracy is discussed. They embrace a modern, adapted heritage two-step algorithm and alternative schemes (deterministic, statistical) that aim at inverting the TOA signal in a single step. These schemes, by the nature of their construction, their robustness, their generalization properties, and their ability to associate uncertainties, are expected to become the new standard in the future. A strategy for atmospheric correction is presented that ensures continuity and consistency with past and present ocean-color missions while enabling full exploitation of the new dimensions and possibilities. Despite the major improvements anticipated with the PACE instruments, gaps/issues remain to be filled/tackled. They include dealing properly with whitecaps, taking into account Earth-curvature effects, correcting for adjacency effects, accounting for the coupling between scattering and absorption, modeling accurately water reflectance, and acquiring a sufficiently representative dataset of water reflectance in the UV to SWIR. Dedicated efforts, experimental and theoretical, are in order to gather the necessary information and rectify inadequacies. Ideas and solutions are put forward to address the unresolved issues. Thanks to its design and characteristics, the PACE mission will mark the beginning of a new era of unprecedented accuracy in ocean-color radiometry from space.
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Affiliation(s)
- Robert J. Frouin
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
- Correspondence: Robert J. Frouin,
| | - Bryan A. Franz
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
| | - Amir Ibrahim
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
- Science Systems and Applications Inc., Lanham, MD, United States
| | - Kirk Knobelspiesse
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
| | - Ziauddin Ahmad
- Ocean Ecology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, United States
- Science Application International Corporation, McLean, VA, United States
| | - Brian Cairns
- NASA Goddard Institute for Space Studies, New York, NY, United States
| | - Jacek Chowdhary
- NASA Goddard Institute for Space Studies, New York, NY, United States
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, United States
| | - Heidi M. Dierssen
- Department of Marine Sciences, University of Connecticut, Groton, CT, United States
| | - Jing Tan
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States
| | - Oleg Dubovik
- Laboratoire d’Optique Atmosphérique, Université de Lille, Villeneuve d’Ascq, France
| | - Xin Huang
- Laboratoire d’Optique Atmosphérique, Université de Lille, Villeneuve d’Ascq, France
| | - Anthony B. Davis
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - Olga Kalashnikova
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - David R. Thompson
- Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA, United States
| | - Lorraine A. Remer
- Joint Center for Earth System Technology, University of Maryland Baltimore County, Baltimore, MD, United States
| | - Emmanuel Boss
- School of Marine Sciences, University of Maine, Orono, ME, United States
| | - Odele Coddington
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, United States
| | | | - Bo-Cai Gao
- Naval Research Laboratory, Washington, DC, United States
| | | | - Otto Hasekamp
- Earth Science Group, Netherlands Institute for Space Research, Utrecht, Netherlands
| | - Ali Omar
- Atmospheric Composition Branch, NASA Langley Research Center, Hampton, VA, United States
| | - Bruno Pelletier
- Institut de Recherche Mathématique, Université de Rennes, Rennes, Franc
| | | | | | - Peng-Wang Zhai
- Department of Physics, University of Maryland Baltimore County, Baltimore, MD, United States
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