Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Skip to content
  • Feedback

    • Chlorophyll-a Average Annual Frequency of Anomalies, 1998-2018 - American Samoa

    Metadata Updated: October 7, 2023

    Chlorophyll-a, is a widely used proxy for phytoplankton biomass and an indicator for changes in phytoplankton production. As an essential source of energy in the marine environment, the extent and availability of phytoplankton biomass can be highly influential for fisheries production and dictate trophic structure in marine ecosystems. Changes in phytoplankton biomass are predominantly effected by changes in nutrient availability, through either natural (e.g., turbulent ocean mixing) or anthropogenic (e.g., agricultural runoff) processes. This layer represents the annual average number of anomalies of chlorophyll-a (mg/m3) from 1998-2018, with values presented as fraction of a year.

    Data products generated by the Ocean Colour component of the European Space Agency (ESA) Climate Change Initiative (CCI) project. These files are 8-day 4-km composites of merged sensor products: Global Area Coverage (GAC), Local Area Coverage (LAC), MEdium Resolution Imaging Spectrometer (MERIS), Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua, Ocean and Land Colour Instrument (OLCI), Sea-viewing Wide Field-of-view Sensor (SeaWiFS), and Visible Infrared Imaging Radiometer Suite (VIIRS).

    The chlorophyll-a average annual frequency of anomalies was calculated by taking the average number of times that the 8-day time series exceeded the maximum monthly climatological chlorophyll-a value from 1998-2018 for each pixel. A quality control mask was applied to remove spurious data associated with shallow water, following Gove et al., 2013. Nearshore map pixels with no data were filled with values from the nearest neighboring valid offshore pixel by using a grid of points and the Near Analysis tool in ArcGIS then converting points to raster.

    Data source: https://oceanwatch.pifsc.noaa.gov/erddap/griddap/esa-cci-chla-8d-v5-0.graph

    Access & Use Information

    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

    Downloads & Resources

    Dates

    Metadata Date September 7, 2021
    Metadata Created Date October 7, 2023
    Metadata Updated Date October 7, 2023
    Reference Date(s) September 7, 2021 (creation), September 7, 2021 (issued), September 7, 2021 (revision)
    Frequency Of Update

    Metadata Source

    Harvested from ioos

    Other Data Resources

    Graphic Preview

    Sample image.

    Additional Metadata

    Resource Type Dataset
    Metadata Date September 7, 2021
    Metadata Created Date October 7, 2023
    Metadata Updated Date October 7, 2023
    Reference Date(s) September 7, 2021 (creation), September 7, 2021 (issued), September 7, 2021 (revision)
    Responsible Party NOAA Pacific Islands Fisheries Science Center (PIFSC) (Point of Contact)
    Contact Email
    Guid as_noaa_all_chlor_anom_freq
    Access Constraints
    Bbox East Long -167.82501847376378
    Bbox North Lat -10.77649
    Bbox South Lat -14.73203864432298
    Bbox West Long -171.33852999999996
    Coupled Resource [{"title": [], "href": ["#DataIdentification"], "uuid": []}, {"title": [], "href": ["#DataIdentification"], "uuid": []}, {"title": [], "href": ["#DataIdentification"], "uuid": []}]
    Frequency Of Update
    Graphic Preview Description Sample image.
    Graphic Preview File http://pacioos.org/metadata/browse/as_noaa_all_chlor_anom_freq.png
    Harvest Object Id 628b7149-247f-40bc-a883-ba494aad53cb
    Harvest Source Id 54e15a6e-6dde-4c9c-a8f0-345cc0dfccfb
    Harvest Source Title ioos
    Licence
    Lineage 2021-09-07T00:00:00Z OGC web services (WMS and WFS) enabled by PacIOOS via GeoServer. Original data from source provider may have been reformatted, reprojected, or adjusted in other ways to optimize these capabilities.
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[-171.33852999999996, -14.73203864432298], [-167.82501847376378, -14.73203864432298], [-167.82501847376378, -10.77649], [-171.33852999999996, -10.77649], [-171.33852999999996, -14.73203864432298]]]}
    Progress
    Spatial Data Service Type Open Geospatial Consortium Web Coverage Service (WCS)
    Spatial Reference System
    Spatial Harvester True

    Didn't find what you're looking for? Suggest a dataset here.