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: nesdisVHNSQchlaDaily)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Files \| Make a graph

To work correctly, this web page requires that JavaScript be enabled in your browser. Please:
1) Enable JavaScript in your browser:
      • Chrome: "Settings : Advanced : Privacy and security : Site Settings : JavaScript"
      • Firefox: (it should be always on!)"
      • Opera: "Settings : Websites : JavaScript"
      • Safari: "Safari : Preferences : Security : Enable JavaScript"
2) Reload this web page.

Dimensions	Size	Spacing
time (Centered Time, UTC)	4222	1 day 2h 52m 17s (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)

(Documentation / Bypass this form)

(Please be patient. It may take a while to get the data.)

The Dataset Attribute Structure (.das) for this Dataset

Attributes {
  time {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.325592e+9, 1.7339184e+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/L3/2024/12/11/V2024346_D1_WW00_chlor_a.nc   Fri Dec 20 19:17:11 2024
: /data/data652/coastwatch/oc/L3/scripts/bin/l3cnvtr -r 4 /data/data369/viirs/L3/2024/12/11/V2024346_D1_WW00_chlor_a.nc /data/aftp/socd1/mecb/coastwatch/viirs/science/L3/global/chlora/daily/WW00/V2024346_D1_WW00_chlora.nc
2024-12-22T06:26:04Z (local files)
2024-12-22T06:26:04Z https://polarwatch.noaa.gov/erddap/griddap/nesdisVHNSQchlaDaily.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,HILT,HISATZEN,CLOUD,HISOLZEN,LOWLW,CHLFAIL,NAVWARN,CLDSHDSTL,MAXAERITER,CHLWARN,ALGICE,SEAICE,NAVFAIL,FILTER";
    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 "2024-12-11T12:00:00Z";
    String time_coverage_resolution "PD1";
    String time_coverage_start "2012-01-03T12:00:00Z";
    String title "Chlorophyll, NOAA S-NPP VIIRS, Science Quality, Global 4km, Level 3, 2012-present, Daily";
    Float64 Westernmost_Easting -179.98125;
  }
}

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 (external link)

Data Access Protocol (DAP) (external link)

and its projection constraints (external link)

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.