ERDDAP > griddap > Data Access Form

Dataset Title:	Chlorophyll, NOAA S-NPP VIIRS, Science Quality, Global 4km, Level 3, 2012- present, Daily
Institution:	NOAA NESDIS CoastWatch   (Dataset ID: noaacwNPPVIIRSSQchlaDaily)
Information:	Summary | License | FGDC | ISO 19115 | Metadata | Background | Files | Make a graph

 

Dimensions	Start	Stride	Stop	Size	Spacing
time (Centered Time, UTC)				4594	1 day 2h 39m 35s (uneven)
altitude (m)				1	(just one value)
latitude (degrees_north)				4788	-0.0375 (even)
longitude (degrees_east)				9600	0.0375 (even)

Grid Variables (which always also download all of the dimension variables)

chlor_a (Chlorophyll Concentration, Default Algorithm, mg m^-3)

File type: (more information) .asc - View OPeNDAP-style ISO-8859-1 comma-separated text. .croissant - Download the dataset croissant schema. .csv - Download a ISO-8859-1 comma-separated text table (line 1: names; line 2: units; ISO 8601 times). .csv0 - Download a ISO-8859-1 .csv file without column names or units. Times are ISO 8601 strings. .csvp - Download a ISO-8859-1 .csv file with line 1: name (units). Times are ISO 8601 strings. .das - View the dataset's metadata via an ISO-8859-1 OPeNDAP Dataset Attribute Structure (DAS). .dds - View the dataset's structure via an ISO-8859-1 OPeNDAP Dataset Descriptor Structure (DDS). .dods - OPeNDAP clients use this to download the data in the DODS binary format. .esriAscii - Download an ISO-8859-1 ESRI ASCII file (latitude longitude data only; longitude must be all below or all above 180). .fgdc - View the dataset's UTF-8 FGDC .xml metadata. .htmlTable - View a UTF-8 .html web page with the data in a table. Times are ISO 8601 strings. .iso19115 - View the dataset's ISO 19115/19139 UTF-8 .xml metadata using the version default for this server. .iso19115_2 - View the dataset's ISO 19115-2/19139 UTF-8 .xml metadata. .iso19115_3_2016 - View the dataset's ISO 19115-3:2016 UTF-8 .xml metadata. .iso19139_2007 - View the dataset's ISO 19139:2007 UTF-8 .xml metadata. .itx - Download an ISO-8859-1 Igor Text File. Each axis variable and each data variable becomes a wave. .json - View a table-like UTF-8 JSON file (missing value = 'null'; times are ISO 8601 strings). .jsonlCSV - View a UTF-8 JSON Lines CSV file without column names (mv = 'null'; times are ISO 8601 strings). .jsonlCSV1 - View a UTF-8 JSON Lines CSV file with column names on line 1 (mv = 'null'; times are ISO 8601 strings). .jsonlKVP - View a UTF-8 JSON Lines file with Key:Value pairs (missing value = 'null'; times are ISO 8601 strings). .mat - Download a MATLAB binary file. .nc - Download a NetCDF-3 binary file with COARDS/CF/ACDD metadata. .ncHeader - View the UTF-8 header (the metadata) for the NetCDF-3 .nc file. .nccsv - Download a NetCDF-3-like 7-bit ASCII NCCSV .csv file with COARDS/CF/ACDD metadata. .nccsvMetadata - View the dataset's metadata as the top half of a 7-bit ASCII NCCSV .csv file. .ncml - View the dataset's structure and metadata as a UTF-8 NCML .xml file. .ncoJson - Download a UTF-8 NCO lvl=2 JSON file with COARDS/CF/ACDD metadata. .odvTxt - Download time,latitude,longitude,otherVariables as an ODV Generic Spreadsheet File (.txt). .parquet - Download as a parquet file. Metadata contains column names ("column_names") and units ("column_units"). .parquetWMeta - Download as a parquet file with detailed metadata. .timeGaps - View a UTF-8 list of gaps in the time values which are larger than the median gap. .tsv - Download a ISO-8859-1 tab-separated text table (line 1: names; line 2: units; ISO 8601 times). .tsv0 - Download a ISO-8859-1 .tsv file without column names or units. Times are ISO 8601 strings. .tsvp - Download a ISO-8859-1 .tsv file with line 1: name (units). Times are ISO 8601 strings. .wav - Download a .wav audio file. All columns must be numeric and of the same type. .xhtml - View a UTF-8 XHTML (XML) file with the data in a table. Times are ISO 8601 strings. .geotif - View a grayscale GeoTIFF .tif file (for latitude longitude data; longitude must be all below or all above 180). .kml - View a Google Earth .kml file (for latitude, longitude data only). .largePdf - View a large .pdf image file with a graph or map. .largePng - View a large .png image file with a graph or map. .pdf - View a standard, medium-sized .pdf image file with a graph or map. .png - View a standard, medium-sized .png image file with a graph or map. .smallPdf - View a small .pdf image file with a graph or map. .smallPng - View a small .png image file with a graph or map. .transparentPng - View a .png image file (just the data, without axes, landmask, or legend).

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The Dataset Attribute Structure (.das) for this Dataset

Attributes {
  time {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.3255056e+9, 1.7663184e+9;
    String axis "T";
    String calendar "gregorian";
    String coverage_content_type "coordinate";
    String ioos_category "Time";
    String long_name "Centered Time";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String units "seconds since 1970-01-01T00:00:00Z";
  }
  altitude {
    String _CoordinateAxisType "Height";
    String _CoordinateZisPositive "up";
    Float64 actual_range 0.0, 0.0;
    String axis "Z";
    String coverage_content_type "coordinate";
    String ioos_category "Location";
    String long_name "Altitude";
    String positive "up";
    String standard_name "altitude";
    String units "m";
  }
  latitude {
    String _CoordinateAxisType "Lat";
    Float64 actual_range -89.75625, 89.75625;
    String axis "Y";
    String comment "The latitude values are the centers of the grid cells.";
    String coverage_content_type "coordinate";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String units "degrees_north";
    Float64 valid_max 90.0;
    Float64 valid_min -90.0;
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range -179.98125, 179.98125;
    String axis "X";
    String comment "The longitude values are the centers of the grid cells.";
    String coverage_content_type "coordinate";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String units "degrees_east";
    Float64 valid_max 180.0;
    Float64 valid_min -180.0;
  }
  chlor_a {
    Float32 _FillValue -999.0;
    String C_format "%.4g";
    String cell_methods "time:mean(interval:1 day)";
    Float64 colorBarMaximum 30.0;
    Float64 colorBarMinimum 0.03;
    String colorBarScale "Log";
    String coverage_content_type "physicalMeasurement";
    String grid_mapping "coord_ref";
    String ioos_category "Ocean Color";
    String long_name "Chlorophyll Concentration, Default Algorithm";
    String references "O and #39;Reilly J. E. et al. (1998), Ocean color chlorophyll algorithms for SeaWiFS, J. Geophys. Res., 103(C11), 2493724953";
    String standard_name "mass_concentration_of_chlorophyll_a_in_sea_water";
    String units "mg m^-3";
    Float32 valid_max 100.0;
    Float32 valid_min 0.001;
  }
  NC_GLOBAL {
    String cdm_data_type "Grid";
    String comment "This is science quality data.";
    String Conventions "CF-1.6, COARDS, ACDD-1.3";
    String creator_email "coastwatch.info@noaa.gov";
    String creator_name "NOAA CoastWatch";
    String creator_type "institution";
    String creator_url "https://coastwatch.noaa.gov";
    Float64 Easternmost_Easting 179.98125;
    Float64 geospatial_lat_max 89.75625;
    Float64 geospatial_lat_min -89.75625;
    Float64 geospatial_lat_resolution 0.0375;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 179.98125;
    Float64 geospatial_lon_min -179.98125;
    Float64 geospatial_lon_resolution 0.0375;
    String geospatial_lon_units "degrees_east";
    Float64 geospatial_vertical_max 0.0;
    Float64 geospatial_vertical_min 0.0;
    String geospatial_vertical_positive "up";
    String geospatial_vertical_units "m";
    String grid_mapping_name "latitude_longitude";
    String history 
"/data/data369/hgu/v224/bin/l3mapgen par=/data/data652/coastwatch/oc/L3/scripts/bin/../config/l3mapgen_par_chlor_a ifile=/data/data652/coastwatch/oc/L3/scripts/bin/../temp/Config_bmw/infile_2km_G.nc ofile=/data/data369/viirs/L3/2025/12/21/V2025355_D1_WW00_chlor_a.nc   Tue Dec 30 19:15:30 2025
: /data/data652/coastwatch/oc/L3/scripts/bin/l3cnvtr -r 4 /data/data369/viirs/L3/2025/12/21/V2025355_D1_WW00_chlor_a.nc /data/aftp/socd1/mecb/coastwatch/viirs/science/L3/global/chlora/daily/WW00/V2025355_D1_WW00_chlora.nc
2025-12-31T22:26:41Z (local files)
2025-12-31T22:26:41Z https://coastwatch.noaa.gov/erddap/griddap/noaacwNPPVIIRSSQchlaDaily.das";
    String id "noaacwNPPVIIRSSQchlaDaily";
    String identifier_product_doi "https://dx.doi.org";
    String identifier_product_doi_authority "https://dx.doi.org";
    String infoUrl "https://coastwatch.noaa.gov/cw/satellite-data-products/ocean-color/science-quality/viirs-snpp.html";
    String institution "NOAA NESDIS CoastWatch";
    String instrument "VIIRS";
    String keywords "algorithm, altitude, chemistry, chlor_a, chlorophyll, color, concentration, daily, data, default, Earth Science  > Oceans  > Ocean Chemistry  > Chlorophyll, image, imager, imager/radiometer, imaging, infrared, L3, latitude, level, level-3, longitude, mapped, mass, mass_concentration_of_chlorophyll_a_in_sea_water, national, npp, ocean, ocean color, oceans, Oceans  > Ocean Optics  > Ocean Color, optics, orbiting, partnership, polar, polar-orbiting, radiometer, sea, seawater, smi, standard, star, suite, suite/suomi-npp, suomi, time, VIIRS, viirs, viirs-n, visible, water, ww00";
    String keywords_vocabulary "GCMD Science Keywords";
    String l2_flag_names "ATMFAIL,LAND,HIGLINT,BADLT,HISATZEN,CLOUD,HISOLZEN,CHLFAIL,NAVWARN,CLDSHDSTL,CHLWARN,ALGICE,SEAICE,NAVFAIL";
    String license 
"https://science.nasa.gov/earth-science/earth-science-data/data-information-policy/

Please acknowledge the use of these data with the following statement: \\\"These data were provided by NOAA's Center for Satellite Applications and Research (STAR) and the CoastWatch program.\\\" To reference these data as a citation in a paper, please follow the instructions in the license and at this link: https://coastwatch.noaa.gov/erddap/information.html#citeDataset";
    String map_projection "geographic";
    String measure "Mean";
    String naming_authority "gov.noaa.coastwatch";
    Float64 Northernmost_Northing 89.75625;
    String platform "Suomi-NPP";
    String processing_level "L3 Mapped";
    String processing_version "Unspecified";
    String product_name "NOAA S-NPP VIIRS ocean color products from CoastWatch";
    String project "Ocean Color Science Team (NOAA/NESDIS/STAR/OCST)";
    String publisher_email "coastwatch.info@noaa.gov";
    String publisher_name "NOAA CoastWatch Central";
    String publisher_type "group";
    String publisher_url "https://coastwatch.noaa.gov/erddap/";
    String references "O and #39;Reilly J. E. et al. (1998), Ocean color chlorophyll algorithms for SeaWiFS, J. Geophys. Res., 103(C11), 2493724953";
    String Satellite "Suomi-NPP";
    String Sensor "VIIRS";
    String source "Satellite observations from VIIRS ocean color sensor";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing -89.75625;
    String spatialResolution "4.17 km";
    String standard_name_vocabulary "CF Standard Name Table v29";
    String summary "Level-3 Standard Mapped Image (SMI), Global, 4km, Chlorophyll, Daily composite data from the Visible and Infrared Imager/Radiometer Suite (VIIRS). These are science quality data with a 15-day latency. The data, processed by the NOAA/STAR Ocean Color Team, are produced from MSL12 v1.2 using OC-SDR v04 and were release by CoastWatch as of 2017-08-07. VIIRS is a multi-disciplinary instrument that flies on the Suomi-NPP (National Polar-orbiting Partnership) satellite and is the successor to MODIS. Suomi-NPP is the initial spacecraft in the JPSS (Joint Polar Satellite Systems) series of spacecraft. JPSS is our Nation's next generation polar-orbiting operational environmental satellite system. JPSS is a collaborative program between NOAA and its acquisition agent NASA.";
    String temporal_range "day";
    String testOutOfDate "now-2days";
    String time_coverage_end "2025-12-21T12:00:00Z";
    String time_coverage_resolution "PD1";
    String time_coverage_start "2012-01-02T12:00:00Z";
    String title "Chlorophyll, NOAA S-NPP VIIRS, Science Quality, Global 4km, Level 3, 2012-present, Daily";
    Float64 Westernmost_Easting -179.98125;
  }
}

 

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Using griddap to Request Data and Graphs from Gridded Datasets

griddap lets you request a data subset, graph, or map from a gridded dataset (for example, sea surface temperature data from a satellite), via a specially formed URL. griddap uses the OPeNDAP Data Access Protocol (DAP) and its projection constraints.

The URL specifies what you want: the dataset, a description of the graph or the subset of the data, and the file type for the response.

• (easy) You can get data by using the dataset's Data Access Form. It makes the URL for you.
• (easy) You can make a graph or map by using the dataset's Make A Graph form. It makes the URL for you.
• (not hard) You can bypass the forms and get the data or make a graph or map by generating the URL by hand or with a computer program or script.

griddap request URLs must be in the form
https://coastwatch.pfeg.noaa.gov/erddap/griddap/datasetID.fileType{?query}
For example,
https://coastwatch.pfeg.noaa.gov/erddap/griddap/jplMURSST41.htmlTable?analysed_sst[(2002-06-01T09:00:00Z)][(-89.99):1000:(89.99)][(-179.99):1000:(180.0)]
Thus, the query is often a data variable name (e.g., analysed_sst), followed by [(start):stride:(stop)] (or a shorter variation of that) for each of the variable's dimensions (for example, [time][latitude][longitude]).

For details, see the griddap Documentation.