Aquatic biogeochemistry explores the biological, chemical, geological (and physical) processes in the ocean and other water bodies. From perspective of PACE, BGC products target selected metrics of the aquatic BGC through a suite of algorithms, some applicable to all the Ocean Color missions, and some available from PACE only. Here, we validate the individual products from PACE BGC suite.
Chlorophyll-a is a major photosynthetic pigment, found in phytoplankton in all aquatic bodies. Chlorophyll-a product from PACE-OCI (chlor_a), is calculated using relationships derived from in situ measurements of both chlor_a and spectral remote sensing reflectances (Rrs) (Werdell et al. 2023).
Particulate Organic Carbon is an important part of the oceanic carbon pool, composed of living (phytoplankton, bacteria, zooplankton) and non-living (e.g., detritus) organic material, directly linked to the major biogeochemical processes and state of the ecosystems of the ocean. Particulate Organic Carbon product from PACE-OCI (POC), is calculated using relationships derived from in situ measurements of both POC and spectral remote sensing reflectance (Rrs) (Stramski et al. 2022, Stramski et al. 2024).
For validation of the chlor_a product we use chlor_a data collected across aquatic ecosystems and analyzed with high pressure liquid chromatography method at NASA Ocean Ecology Laboratory. For validation of the POC product we use POC data collected across aquatic ecosystems and analyzed following the recommended IOCCG protocols.
These data were collected by members of the PACE Validation Science team, and other NASA funded scientists. In situ dataset was quality controlled according to the latest protocols from the IOCCG Ocean Optics & Biogeochemistry Protocols for Satellite Ocean Colour Sensor Validation. The data processing involves extracting satellite data and matching it with corresponding field measurements based on temporal and spatial proximity. Matched pairs are filtered based on criteria described in Bailey and Werdell (2006) and in the SeaBASS validation protocols.
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Aquatic Biogeochemistry Click to download data: Select BGC matchup statistics | Select Chl-a match-up | Select POC match-up |
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| Product | Number_of_Points | Scale_Independence | Mean Bias | Limits of Agreement | Linear Slope | Linear Intercept | Linear Correlation | Rank Correlation | RMSE [View plot] |
MAE [View plot] |
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| Low | High | ||||||||||
| Chl-a | 52 | FALSE | 0.0378 | -0.163 | 0.239 | 0.945 | 0.0308 | 0.954 | 0.931 | 0.205 | 0.163 |
| POC | 7 | FALSE | 0.065 | -0.0274 | 0.157 | 1.031 | 0.0046 | 0.9 | 0.964 | 0.113 | 0.104 |
