Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering model
<p>The particle size distribution (PSD) of suspended particles in near-surface seawater is a key property linking biogeochemical and ecosystem characteristics with optical properties that affect ocean color remote sensing. Phytoplankton size affects their physiological characteristics and ecos...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-05-01
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| Series: | Ocean Science |
| Online Access: | https://os.copernicus.org/articles/19/703/2023/os-19-703-2023.pdf |
| _version_ | 1797819742369611776 |
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| author | T. S. Kostadinov L. Robertson Lain C. E. Kong X. Zhang S. Maritorena S. Bernard H. Loisel D. S. F. Jorge E. Kochetkova S. Roy B. Jonsson V. Martinez-Vicente S. Sathyendranath |
| author_facet | T. S. Kostadinov L. Robertson Lain C. E. Kong X. Zhang S. Maritorena S. Bernard H. Loisel D. S. F. Jorge E. Kochetkova S. Roy B. Jonsson V. Martinez-Vicente S. Sathyendranath |
| author_sort | T. S. Kostadinov |
| collection | DOAJ |
| description | <p>The particle size distribution (PSD) of suspended particles in near-surface seawater is a key property linking biogeochemical and ecosystem characteristics with optical properties that affect ocean color remote sensing. Phytoplankton size affects their physiological characteristics and ecosystem and biogeochemical roles, e.g., in the biological carbon pump, which has an important role in the global carbon cycle and thus climate. It is thus important to develop capabilities for measurement and predictive understanding of the structure and function of oceanic ecosystems, including the PSD, phytoplankton size classes (PSCs), and phytoplankton functional types (PFTs). Here, we present an ocean color satellite algorithm for the retrieval of the parameters of an assumed power-law PSD. The forward optical model considers two distinct particle populations: phytoplankton and non-algal particles (NAPs). Phytoplankton are modeled as coated spheres following the Equivalent Algal Populations (EAP) framework, and NAPs are modeled as homogeneous spheres. The forward model uses Mie and Aden–Kerker scattering computations, for homogeneous and coated spheres, respectively, to model the total particulate spectral backscattering coefficient as the sum of phytoplankton and NAP backscattering. The PSD retrieval is achieved via spectral angle mapping (SAM), which uses backscattering end-members created by the forward model. The PSD is used to retrieve size-partitioned absolute and fractional phytoplankton carbon concentrations (i.e., carbon-based PSCs), as well as particulate organic carbon (POC), using allometric coefficients. This model formulation also allows the estimation of chlorophyll <span class="inline-formula"><i>a</i></span> concentration via the retrieved PSD, as well as percent of backscattering due to NAPs vs. phytoplankton. The PSD algorithm is operationally applied to the merged Ocean<span id="page704"/> Colour Climate Change Initiative (OC-CCI) v5.0 ocean color data set. Results of an initial validation effort are also presented using PSD, POC, and picophytoplankton carbon in situ measurements. Validation results indicate the need for an empirical tuning for the absolute phytoplankton carbon concentrations; however these results and comparison with other phytoplankton carbon algorithms are ambiguous as to the need for the tuning. The latter finding illustrates the continued need for high-quality, consistent, large global data sets of PSD, phytoplankton carbon, and related variables to facilitate future algorithm improvements.</p> |
| first_indexed | 2024-03-13T09:28:04Z |
| format | Article |
| id | doaj.art-4ac8b8f003a149ba9f3f147323a6cf49 |
| institution | Directory Open Access Journal |
| issn | 1812-0784 1812-0792 |
| language | English |
| last_indexed | 2024-03-13T09:28:04Z |
| publishDate | 2023-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Ocean Science |
| spelling | doaj.art-4ac8b8f003a149ba9f3f147323a6cf492023-05-26T06:38:14ZengCopernicus PublicationsOcean Science1812-07841812-07922023-05-011970372710.5194/os-19-703-2023Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering modelT. S. Kostadinov0L. Robertson Lain1C. E. Kong2X. Zhang3S. Maritorena4S. Bernard5H. Loisel6D. S. F. Jorge7E. Kochetkova8S. Roy9B. Jonsson10V. Martinez-Vicente11S. Sathyendranath12Department of Liberal Studies, California State University San Marcos, 333 S. Twin Oaks Valley Rd., San Marcos, CA 92096, USAEarth Observation, Smart Places, CSIR 7700, Cape Town, South AfricaPlymouth Marine Laboratory, Prospect Place, Plymouth, Devon, PL1 3DH, UKDivision of Marine Science, School of Ocean Science and Engineering, The University of Southern Mississippi, Stennis Space Center, MS 39529, USAEarth Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-3060, USASANSA, Enterprise Building, Mark Shuttleworth Street, Innovation Hub, Pretoria 0087, South AfricaUniv. Littoral Côte d'Opale, CNRS, Univ. Lille, IRD, UMR 8187 – LOG – Laboratoire d'Océanologie et de Géosciences, 62930 Wimereux, FranceUniv. Littoral Côte d'Opale, CNRS, Univ. Lille, IRD, UMR 8187 – LOG – Laboratoire d'Océanologie et de Géosciences, 62930 Wimereux, FranceDepartment of Earth and Environmental Science, Hayden Hall, University of Pennsylvania, 240 South 33rd St., Philadelphia, PA 19104, USADepartment of Geography and Environmental Science, University of Reading, Reading, RG6 6DW, UKNational Centre for Earth Observation, Plymouth Marine Laboratory, Prospect Place, Plymouth, Devon, PL1 3DH, UKPlymouth Marine Laboratory, Prospect Place, Plymouth, Devon, PL1 3DH, UKNational Centre for Earth Observation, Plymouth Marine Laboratory, Prospect Place, Plymouth, Devon, PL1 3DH, UK<p>The particle size distribution (PSD) of suspended particles in near-surface seawater is a key property linking biogeochemical and ecosystem characteristics with optical properties that affect ocean color remote sensing. Phytoplankton size affects their physiological characteristics and ecosystem and biogeochemical roles, e.g., in the biological carbon pump, which has an important role in the global carbon cycle and thus climate. It is thus important to develop capabilities for measurement and predictive understanding of the structure and function of oceanic ecosystems, including the PSD, phytoplankton size classes (PSCs), and phytoplankton functional types (PFTs). Here, we present an ocean color satellite algorithm for the retrieval of the parameters of an assumed power-law PSD. The forward optical model considers two distinct particle populations: phytoplankton and non-algal particles (NAPs). Phytoplankton are modeled as coated spheres following the Equivalent Algal Populations (EAP) framework, and NAPs are modeled as homogeneous spheres. The forward model uses Mie and Aden–Kerker scattering computations, for homogeneous and coated spheres, respectively, to model the total particulate spectral backscattering coefficient as the sum of phytoplankton and NAP backscattering. The PSD retrieval is achieved via spectral angle mapping (SAM), which uses backscattering end-members created by the forward model. The PSD is used to retrieve size-partitioned absolute and fractional phytoplankton carbon concentrations (i.e., carbon-based PSCs), as well as particulate organic carbon (POC), using allometric coefficients. This model formulation also allows the estimation of chlorophyll <span class="inline-formula"><i>a</i></span> concentration via the retrieved PSD, as well as percent of backscattering due to NAPs vs. phytoplankton. The PSD algorithm is operationally applied to the merged Ocean<span id="page704"/> Colour Climate Change Initiative (OC-CCI) v5.0 ocean color data set. Results of an initial validation effort are also presented using PSD, POC, and picophytoplankton carbon in situ measurements. Validation results indicate the need for an empirical tuning for the absolute phytoplankton carbon concentrations; however these results and comparison with other phytoplankton carbon algorithms are ambiguous as to the need for the tuning. The latter finding illustrates the continued need for high-quality, consistent, large global data sets of PSD, phytoplankton carbon, and related variables to facilitate future algorithm improvements.</p>https://os.copernicus.org/articles/19/703/2023/os-19-703-2023.pdf |
| spellingShingle | T. S. Kostadinov L. Robertson Lain C. E. Kong X. Zhang S. Maritorena S. Bernard H. Loisel D. S. F. Jorge E. Kochetkova S. Roy B. Jonsson V. Martinez-Vicente S. Sathyendranath Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering model Ocean Science |
| title | Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering model |
| title_full | Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering model |
| title_fullStr | Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering model |
| title_full_unstemmed | Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering model |
| title_short | Ocean color algorithm for the retrieval of the particle size distribution and carbon-based phytoplankton size classes using a two-component coated-sphere backscattering model |
| title_sort | ocean color algorithm for the retrieval of the particle size distribution and carbon based phytoplankton size classes using a two component coated sphere backscattering model |
| url | https://os.copernicus.org/articles/19/703/2023/os-19-703-2023.pdf |
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