Data Access Form

Dataset Title:	NRT merged all satellites Global Ocean Gridded SSALTO/DUACS Sea Surface Height L4 product and derived variables 2023
Institution:	CLS, CNES (Dataset ID: SEA_SURFACE_HEIGHT_NRT_2023)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Files \| Make a graph

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Dimensions	Size	Spacing
time (UTC)	365	1 day (even)

latitude (degrees_north)	720	0.25 (even)

longitude (degrees_east)	1440	0.25 (even)

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

adt (Absolute dynamic topography, m)

ugos (Absolute geostrophic velocity: zonal component, m/s)

vgos (Absolute geostrophic velocity: meridian component, m/s)

sla (Sea level anomaly, m)

ugosa (Geostrophic velocity anomalies: zonal component, m/s)

vgosa (Geostrophic velocity anomalies: meridian component, m/s)

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 1.6725312e+9, 1.7039808e+9;
    String axis "T";
    String calendar "gregorian";
    String ioos_category "Time";
    String long_name "Time";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String units "seconds since 1970-01-01T00:00:00Z";
  }
  latitude {
    String _CoordinateAxisType "Lat";
    Float64 actual_range -89.875, 89.875;
    String axis "Y";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String units "degrees_north";
    Float64 valid_max 89.875;
    Float64 valid_min -89.875;
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float64 actual_range -179.875, 179.875;
    String axis "X";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String units "degrees_east";
    Float64 valid_max 179.875;
    Float64 valid_min -179.875;
  }
  adt {
    Float64 _FillValue 0.0;
    Float64 colorBarMaximum 2.0;
    Float64 colorBarMinimum -2.0;
    String comment "The absolute dynamic topography is the sea surface height above geoid; the adt is obtained as follows: adt=sla+mdt where mdt is the mean dynamic topography; see the product user manual for details";
    String ioos_category "Bathymetry";
    String long_name "Absolute dynamic topography";
    String standard_name "sea_surface_height_above_geoid";
    String units "m";
  }
  ugos {
    Float64 _FillValue 0.0;
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String ioos_category "Currents";
    String long_name "Absolute geostrophic velocity: zonal component";
    String standard_name "surface_geostrophic_eastward_sea_water_velocity";
    String units "m/s";
  }
  vgos {
    Float64 _FillValue 0.0;
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String ioos_category "Currents";
    String long_name "Absolute geostrophic velocity: meridian component";
    String standard_name "surface_geostrophic_northward_sea_water_velocity";
    String units "m/s";
  }
  sla {
    Float64 _FillValue 0.0;
    Float64 colorBarMaximum 1.0;
    Float64 colorBarMinimum -1.0;
    String comment "The sea level anomaly is the sea surface height above mean sea surface; it is referenced to the [1993, 2012] period; see the product user manual for details";
    String ioos_category "Sea Level";
    String long_name "Sea level anomaly";
    String standard_name "sea_surface_height_above_sea_level";
    String units "m";
  }
  ugosa {
    Float64 _FillValue 0.0;
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String comment "The geostrophic velocity anomalies are referenced to the [1993, 2012] period";
    String ioos_category "Sea Level";
    String long_name "Geostrophic velocity anomalies: zonal component";
    String standard_name "surface_geostrophic_eastward_sea_water_velocity_assuming_sea_level_for_geoid";
    String units "m/s";
  }
  vgosa {
    Float64 _FillValue 0.0;
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String comment "The geostrophic velocity anomalies are referenced to the [1993, 2012] period";
    String ioos_category "Sea Level";
    String long_name "Geostrophic velocity anomalies: meridian component";
    String standard_name "surface_geostrophic_northward_sea_water_velocity_assuming_sea_level_for_geoid";
    String units "m/s";
  }
  NC_GLOBAL {
    String cdm_data_type "Grid";
    String comment "Sea Surface Height measured by Altimetry and derived variables";
    String contact "servicedesk.cmems@mercator-ocean.eu";
    String Conventions "CF-1.10, COARDS, ACDD-1.3";
    String creator_email "servicedesk.cmems@mercator-ocean.eu";
    String creator_name "CMEMS - Sea Level Thematic Assembly Center";
    String creator_type "group";
    String creator_url "http://marine.copernicus.eu";
    String date_created "2024-01-06T00:55:11Z";
    String date_issued "2024-01-06T00:55:11Z";
    String date_modified "2024-01-06T00:55:11Z";
    Float64 Easternmost_Easting 179.875;
    Float64 geospatial_lat_max 89.875;
    Float64 geospatial_lat_min -89.875;
    Float64 geospatial_lat_resolution 0.25;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 179.875;
    Float64 geospatial_lon_min -179.875;
    Float64 geospatial_lon_resolution 0.25;
    String geospatial_lon_units "degrees_east";
    String geospatial_vertica_resolution "point";
    String history 
"2024-01-06 00:55:12Z: Creation
2025-04-26T00:44:50Z (local files)
2025-04-26T00:44:50Z https://erddap.aoml.noaa.gov/hdb/erddap/griddap/SEA_SURFACE_HEIGHT_NRT_2023.das";
    String infoUrl "http://marine.copernicus.eu";
    String institution "CLS, CNES";
    String keywords "above, absolute, adt, all, anomalies, anomaly, assuming, bathymetry, centre, circulation, cls, cnes, collecte, component, currents, data, derived, duacs, dynamic, earth, Earth Science > Oceans > Ocean Circulation > Ocean Currents, Earth Science > Oceans > Ocean Topography > Sea Surface Height, Earth Science > Oceans > Sea Surface Topography > Sea Surface Height, Earth Science > Solid Earth > Geodetics/Gravity > Geoid Properties, eastward, etudes, geodetics, geoid, geostrophic, global, gravity, gridded, height, L4, latitude, level, localisation, longitude, merged, meridian, national, near, northward, nrt, ocean, oceans, product, properties, real, satellites, science, sea, sea level, sea_surface_height_above_geoid, sea_surface_height_above_sea_level, seawater, sla, solid, spatiales, ssalto, ssh, surface, surface_geostrophic_eastward_sea_water_velocity, surface_geostrophic_eastward_sea_water_velocity_assuming_sea_level_for_geoid, surface_geostrophic_northward_sea_water_velocity, surface_geostrophic_northward_sea_water_velocity_assuming_sea_level_for_geoid, time, topography, ugos, ugosa, velocity, vgos, vgosa, water, zonal";
    String keywords_vocabulary "GCMD Science Keywords";
    String license "http://marine.copernicus.eu/web/27-service-commitments-and-licence.php";
    Float64 Northernmost_Northing 89.875;
    String platform "Altika, Cryosat-2 New Orbit, Haiyang-2B, Jason-3 Interleaved, Sentinel-3A, Sentinel-3B, Sentinel-6A";
    String processing_level "L4";
    String product_version "vDec2021";
    String project "COPERNICUS MARINE ENVIRONMENT MONITORING SERVICE (CMEMS)";
    String references "http://marine.copernicus.eu";
    String software_version "19.2.0_DUACS_DT2021_baseline";
    String source "Altimetry measurements";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing -89.875;
    String ssalto_duacs_comment "Sentinel-6A is the reference mission used for the altimeter inter-calibration processing";
    String standard_name_vocabulary "CF Standard Name Table v70";
    String summary "SSALTO/DUACS Near-Real-Time Level-4 sea surface height and derived variables measured by multi-satellite altimetry observations over Global Ocean.";
    String testOutOfDate "now-2days";
    String time_coverage_duration "P1D";
    String time_coverage_end "2023-12-31T00:00:00Z";
    String time_coverage_resolution "P1D";
    String time_coverage_start "2023-01-01T00:00:00Z";
    String title "NRT merged all satellites Global Ocean Gridded SSALTO/DUACS Sea Surface Height L4 product and derived variables 2023";
    Float64 Westernmost_Easting -179.875;
  }
}

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.