Global Chlorophyll <i>a</i> Concentrations of Phytoplankton Functional Types With Detailed Uncertainty Assessment Using Multisensor Ocean Color and Sea Surface Temperature Satellite Products

Xi, Hongyan; Losa, Svetlana N.; Mangin, Antoine; Garnesson, Philippe; Bretagnon, Marine; Demaria, Julien; Soppa, Mariana Altenburg; d'Andon, Odile Hembise Fanton; Bracher, Astrid

doi:10.1029/2020jc017127

Cited by 28 publications

(15 citation statements)

References 69 publications

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“…Our results also illustrate the potential for combining satellite data from multiple platforms in a neural network framework. The inclusion of ancillary environmental information such as water temperature and salinity can improve phytoplankton group modeling efforts (Figure S10 and Table S2 in Supporting Information S1; see also Brewin et al, 2019;Xi et al, 2021). Looking forward, the upcoming NASA Plankton, Aerosol, Cloud, and ocean Ecosystem (PACE) mission will include polarimetry and hyperspectral ocean color instruments that can potentially be combined with other remotely sensed or modeled data.…”

Section: Discussionmentioning

confidence: 99%

Plankton Imagery Data Inform Satellite‐Based Estimates of Diatom Carbon

Chase

Boss

Haëntjens

et al. 2022

Geophysical Research Letters

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Estimating the biomass of phytoplankton communities via remote sensing is a key requirement for understanding global ocean ecosystems. Of particular interest is the carbon associated with diatoms given their unequivocal ecological and biogeochemical roles. Satellite‐based algorithms often rely on accessory pigment proxies to define diatom biomass, despite a lack of validation against independent diatom biomass measurements. We used imaging‐in‐flow cytometry to quantify diatom carbon in the western North Atlantic, and compared results to those obtained from accessory pigment‐based approximations. Based on this analysis, we offer a new empirical formula to estimate diatom carbon concentrations from chlorophyll a. Additionally, we developed a neural network model in which we integrated chlorophyll a and environmental information to estimate diatom carbon distributions in the western North Atlantic. The potential for improving satellite‐based diatom carbon estimates by integrating environmental information into a model, compared to models that are based solely on chlorophyll a, is discussed.

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Section: Discussionmentioning

confidence: 99%

Plankton Imagery Data Inform Satellite‐Based Estimates of Diatom Carbon

Chase

Boss

Haëntjens

et al. 2022

Geophysical Research Letters

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“…Also, considering that the retrieval algorithm is an emerging technique, further research is necessary to investigate the over-estimation of the lower ranges and under-estimation of higher ranges of PFT Chla, and to promote the introduction of non-linear fitting in the regression model. Finally, another limitation of our EOFbased PFT analysis is the lack of estimation of per-pixel uncertainty, which to our knowledge has only been reported by Brewin et al (2017) and Xi et al (2021). In our study, we used OLCI R rs as the spectral input data derived through the POLYMER algorithm, and the uncertainty for the POLYMER derived R rs is currently under development (Steinmetz, personal communication).…”

Section: Discussionmentioning

confidence: 99%

“…Bracher et al (2015) suggested that at least 50 valid matchup data points are necessary for statistically significant pigment estimation, specifically for open ocean waters. Xi et al (2020) employed a larger number of matchup data points for global open ocean waters, with an even higher number (483) in a more recent publication (Xi et al, 2021). Lange et al (2020) employed 73-78 matchup points to develop an EOF-based algorithm to retrieve phytoplankton cell abundance from MODIS across the Atlantic Ocean.…”

mentioning

confidence: 99%

Seasonal dynamics of major phytoplankton functional types in the coastal waters of the west coast of Canada derived from OLCI Sentinel 3A

Vishnu

Xi²,

Belluz³

et al. 2022

Front. Mar. Sci.

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Monitoring the spatial distribution and seasonal dynamics of phytoplankton functional types (PFTs) in coastal oceans is essential for understanding fisheries production, changes in water quality, and carbon export to the deep ocean. The launch of new generation ocean color sensors such as OLCI (Ocean Land Color Instrument) onboard Sentinel 3A provides an unprecedented opportunity to study the surface dynamics of PFTs at high spatial (300 m) and temporal (daily) resolution. Here we characterize the seasonal dynamics of the major PFTs over the surface waters of the west coast of Canada using OLCI imagery and Chemical Taxonomy (CHEMTAX, v1.95) software. The satellite-based approach was adapted from a previously proven Empirical Orthogonal Function (EOF)-based algorithm by using a local matchup dataset comprising CHEMTAX model output and EOF scores derived from OLCI remote sensing reflectance. The algorithm was developed for the following PFTs: diatoms, dinoflagellates, dictyochophytes, haptophytes, green algae, cryptophytes, cyanobacteria, raphidophytes, and total chlorophyll-a (TChla) concentration. Of these PFTs, first level evaluation of the OLCI-derived retrievals showed reliable performance for diatoms and raphidophytes. The second level of validation showed that TChla had the best performance, and green algae, cryptophytes, and diatoms followed seasonal trends of a high temporal resolution in situ CHEMTAX time-series. Somewhat reduced correspondence was observed for raphidophytes. Due to their low contribution to the phytoplankton community (26%) and low range of variation, weak performance was noted for haptophytes, dictyochophytes, cyanobacteria, and dinoflagellates. The EOF-based PFT maps from daily OLCI imagery showed seasonal spring and fall diatom blooms with succession from spring blooms to high diversity flagellate dominated summer conditions. Furthermore, strong localized summer raphidophyte blooms (Heterosigma akashiwo) were observed, which are a regionally important harmful species. Overall, this study demonstrates the potential of the OLCI in deriving the surface dynamics of major PFTs of the Strait of Georgia (SoG), a critical habitat for the juvenile Pacific Salmon.

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“…In addition, a new high-resolution retrieval algorithm for column densities of BrO has been developed (Seo et al 2019). Long-term (2002-today) time series of phytoplankton groups were derived (Losa et al 2017;Xi et al 2021), which for the first time also deliver phytoplankton group data sets for the Arctic Ocean.…”

Section: B Satellite Data Analysismentioning

confidence: 99%

Atmospheric and Surface Processes, and Feedback Mechanisms Determining Arctic Amplification: A Review of First Results and Prospects of the (AC)3 Project

Wendisch

Brückner

Crewell

et al. 2023

Bulletin of the American Meteorological Society

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Mechanisms behind the phenomenon of Arctic amplification are widely discussed. To contribute to this debate, the (AC)3 project has been established in 2016 (http://www.ac3-tr.de/). It comprises modeling and data analysis efforts as well as observational elements. The project has assembled a wealth of ground-based, airborne, ship-borne, and satellite data of physical, chemical, and meteorological properties of the Arctic atmosphere, cryosphere, and upper ocean that are available for the Arctic climate research community. Short-term changes and indications of long-term trends in Arctic climate parameters have been detected using existing and new data. For example, a distinct atmospheric moistening, an increase of regional storm activities, an amplified winter warming in the Svalbard and North Pole regions, and a decrease of sea ice thickness in the Fram Strait and of snow depth on sea ice have been identified. A positive trend of tropospheric bromine monoxide (BrO) column densities during polar spring was verified. Local marine/biogenic sources for cloud condensation nuclei and ice nucleating particles were found. Atmospheric/ocean and radiative transfer models were advanced by applying new parameterizations of surface albedo, cloud droplet activation, convective plumes and related processes over leads, and turbulent transfer coefficients for stable surface layers. Four modes of the surface radiative energy budget were explored and reproduced by simulations. To advance the future synthesis of the results, cross cutting activities are being developed aiming to answer key questions in four focus areas: lapse rate feedback, surface processes, Arctic mixed-phase clouds, and air mass transport and transformation.

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Global Chlorophyll a Concentrations of Phytoplankton Functional Types With Detailed Uncertainty Assessment Using Multisensor Ocean Color and Sea Surface Temperature Satellite Products

Abstract: As phytoplankton play a fundamental role in marine food webs and biogeochemical cycling, their community structure and taxonomic composition have been widely investigated in recent decades through various observational methods and ecological modeling (e.g.,

Cited by 28 publications

References 69 publications

Plankton Imagery Data Inform Satellite‐Based Estimates of Diatom Carbon

Plankton Imagery Data Inform Satellite‐Based Estimates of Diatom Carbon

Seasonal dynamics of major phytoplankton functional types in the coastal waters of the west coast of Canada derived from OLCI Sentinel 3A

Atmospheric and Surface Processes, and Feedback Mechanisms Determining Arctic Amplification: A Review of First Results and Prospects of the (AC)3 Project

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