Chlorophyll-a Average Annual Frequency of Anomalies, 2002-2013 - Hawaii

Metadata Updated: February 27, 2019

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 2002-2013, with values presented as fraction of a year. Monthly and 8-day 4-km (0.0417-degree) spatial resolution data were obtained from the MODIS (Moderate-resolution Imaging Spectroradiometer) Aqua satellite instrument from the NASA OceanColor website (http://oceancolor.gsfc.nasa.gov).

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 2002-2013 for each pixel. A quality control mask was applied to remove spurious data associated with shallow water, following Gove et al., 2013. Monthly climatologies were calculated from monthly time series using only full years over the Ocean Tipping Points (OTP) project time frame of interest (2002-2013). Time series of anomalies were calculated by quantifying the number and magnitude of events from the 8-day time series that exceed the maximum climatological monthly mean. 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.

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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.

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Dates

Metadata Date March 14, 2017
Metadata Created Date February 27, 2019
Metadata Updated Date February 27, 2019
Reference Date(s) March 14, 2017 (creation), March 14, 2017 (issued), March 14, 2017 (revision)
Frequency Of Update

Metadata Source

Harvested from NOAA CSW Harvest Source

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Sample image.

Additional Metadata

Resource Type Dataset
Metadata Date March 14, 2017
Metadata Created Date February 27, 2019
Metadata Updated Date February 27, 2019
Reference Date(s) March 14, 2017 (creation), March 14, 2017 (issued), March 14, 2017 (revision)
Responsible Party Ocean Tipping Points (OTP) (Point of Contact)
Contact Email
Access Constraints
Bbox East Long -154.56326617912035
Bbox North Lat 22.42373568629166
Bbox South Lat 18.755036208219373
Bbox West Long -160.41246354980814
Coupled Resource [{"href": ["#DataIdentification"], "uuid": [], "title": []}, {"href": ["#DataIdentification"], "uuid": [], "title": []}, {"href": ["#DataIdentification"], "uuid": [], "title": []}]
Frequency Of Update
Graphic Preview Description Sample image.
Graphic Preview File http://pacioos.org/metadata/browse/hi_otp_all_chlor_anom_freq.png
Guid hi_otp_all_chlor_anom_freq
Harvest Object Id 652fe907-f716-4c6f-bf6d-5e2dc9300a0a
Harvest Source Id 2aed8e29-fc5b-4cde-aa66-fb1118fd705e
Harvest Source Title NOAA CSW Harvest Source
Licence
Metadata Language eng
Metadata Type geospatial
Progress
Spatial Data Service Type Open Geospatial Consortium Web Coverage Service (WCS)
Spatial Reference System
Spatial Harvester True

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