Data Access Form

Dataset Title:	Currents, HF Radar, US East Coast and Gulf of Mexico, RTV, Near-Real Time, 2012-present, Hourly, 2km
Institution:	Coastal Observing Research and Development Center, Scripps Institution of Oceanography (Dataset ID: ucsdHfrE2)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Make a graph

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Dimensions	Size	Spacing
time (UTC)	110169	1h 1m 33s (uneven)

latitude (degrees_north)	1380	0.01798 (even)

longitude (degrees_east)	2103	0.0193584 (even)

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

water_u (Surface Eastward Sea Water Velocity, m s-1)

water_v (Surface Northward Sea Water Velocity, m s-1)

DOPx (Longitudinal Dilution of Precision)

DOPy (Latitudinal Dilution of Precision)

hdop (horizontal dilution of precision)

number_of_sites (number of contributing radars, count)

number_of_radials (number of contributing radials, count)

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 1.325376e+9, 1.7321796e+9;
    String axis "T";
    String calendar "proleptic_gregorian";
    String ioos_category "Time";
    String long_name "Forecast time for ForecastModelRunCollection";
    Float64 missing_value NaN;
    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";
    Float32 actual_range 21.7, 46.49442;
    String axis "Y";
    String ioos_category "Location";
    String long_name "Latitude";
    String standard_name "latitude";
    String units "degrees_north";
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float32 actual_range -97.88385, -57.19249;
    String axis "X";
    String ioos_category "Location";
    String long_name "Longitude";
    String standard_name "longitude";
    String units "degrees_east";
  }
  water_u {
    String ancillary_variables "dopx";
    String cell_methods "depth: mean time: mean";
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String grid_mapping "wgs84";
    String ioos_category "Currents";
    String long_name "Surface Eastward Sea Water Velocity";
    String standard_name "surface_eastward_sea_water_velocity";
    String units "m s-1";
  }
  water_v {
    String ancillary_variables "dopy";
    String cell_methods "depth: mean time: mean";
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String grid_mapping "wgs84";
    String ioos_category "Currents";
    String long_name "Surface Northward Sea Water Velocity";
    String standard_name "surface_northward_sea_water_velocity";
    String units "m s-1";
  }
  DOPx {
    Float64 colorBarMaximum 1.0;
    Float64 colorBarMinimum 0.0;
    String colorBarPalette "WhiteRedBlack";
    String comment 
"The longitudinal dilution of precision (dopx) represents the 
contribution of radial geometry to uncertainty in the eastward 
velocity estimate (u).";
    String grid_mapping "wgs84";
    String ioos_category "Currents";
    String long_name "Longitudinal Dilution of Precision";
  }
  DOPy {
    Float64 colorBarMaximum 1.0;
    Float64 colorBarMinimum 0.0;
    String colorBarPalette "WhiteRedBlack";
    String comment 
"The latitudinal dilution of precision (dopy) represents the 
contribution of radial geometry to uncertainty in the northward 
velocity estimate (v).";
    String grid_mapping "wgs84";
    String ioos_category "Currents";
    String long_name "Latitudinal Dilution of Precision";
  }
  hdop {
    String ancillary_variables "dopx dopy";
    Float64 colorBarMaximum 1.0;
    Float64 colorBarMinimum 0.0;
    String comment 
"The horizontal dilution of precision (hdop) is the vector length 
(magnitude) of the eastward (dopx) and northward (dopy) dilution of 
precision.  It represents the contribution of radial geometry to the 
overall uncertainty in the total velocity (u and v) estimate.";
    String ioos_category "Statistics";
    String long_name "horizontal dilution of precision";
  }
  number_of_sites {
    Byte _FillValue -127;
    String _Unsigned "false";
    String colorBarContinuous "false";
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String colorBarNSections "10";
    String comment "Number of radars contributing radials to the total solution";
    String ioos_category "Statistics";
    String long_name "number of contributing radars";
    String units "count";
  }
  number_of_radials {
    Int16 _FillValue -32767;
    Float64 colorBarMaximum 100.0;
    Float64 colorBarMinimum 0.0;
    String comment "Number of radials contributing to the total solution";
    String ioos_category "Statistics";
    String long_name "number of contributing radials";
    String units "count";
  }
  NC_GLOBAL {
    String _CoordSysBuilder "ucar.nc2.dataset.conv.CF1Convention";
    String cdm_data_type "Grid";
    String Conventions "COARDS, CF-1.6, ACDD-1.3";
    String creator_email "hfrnet.administrators@sio.ucsd.edu";
    String creator_name "HFRNet Administrators";
    String creator_type "group";
    String creator_url "https://cordc.ucsd.edu/projects/mapping/";
    String date_created "2024-09-30T20:51:47Z";
    String defaultGraphQuery "&.draw=vectors&.color=0x0000FF";
    Float64 Easternmost_Easting -57.19249;
    String format_version "1.1.00";
    Float64 geospatial_lat_max 46.49442;
    Float64 geospatial_lat_min 21.7;
    Float64 geospatial_lat_resolution 0.01798;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max -57.19249;
    Float64 geospatial_lon_min -97.88385;
    Float64 geospatial_lon_resolution 0.019358401522359656;
    String geospatial_lon_units "degrees_east";
    String history 
"2024-09-30T19:21:51Z hfrnet rtvMergeData: Saving 3527 new solutions
2024-09-30T19:51:52Z hfrnet rtvMergeData: Saving 7280 solutions; 3753 
new or updated, 3527 unmodified from previous run(s)
2024-09-30T20:21:37Z hfrnet rtvMergeData: Saving 7785 solutions; 508 
new or updated, 7277 unmodified from previous run(s)
2024-09-30T20:51:47Z hfrnet rtvMergeData: Saving 8870 solutions; 3371 
new or updated, 5499 unmodified from previous run(s)
2024-09-30T20:51:47Z hfrnet rtvSaveNetcdf: Removed 2389 solutions 
exceeding HDOP threshold of 1.25 ;
FMRC Best Dataset
2024-11-21T12:15:06Z https://hfrnet-tds.ucsd.edu/thredds/dodsC/HFR/USEGC/2km/hourly/RTV/HFRADAR_US_East_and_Gulf_Coast_2km_Resolution_Hourly_RTV_best.ncd
2024-11-21T12:15:06Z https://coastwatch.pfeg.noaa.gov/erddap/griddap/ucsdHfrE2.das";
    String id "202409301800siohfruwlsrtvusegc2km";
    String infoUrl "https://cordc.ucsd.edu/projects/mapping/";
    String institution "Coastal Observing Research and Development Center, Scripps Institution of Oceanography";
    String instrument 
"Earth Remote Sensing Instruments, Active Remote Sensing, 
Profilers/Sounders, Radar Sounders, Doppler RADAR";
    String instrument_vocabulary "Global Change Master Directory (GCMD) Keywords, Version 8.6";
    String keywords "2km, circulation, coast, currents, dilution, Earth Science > Oceans > Ocean Circulation > Ocean Currents, east, east coast, eastward, gulf, gulf of mexico, hf radar, hourly, latitudinal, longitudinal, mexico, near, near real time, northward, ocean, oceans, radar, real, RTV, scripps, sea, seawater, surface, surface_eastward_sea_water_velocity, surface_northward_sea_water_velocity, time, velocity, water";
    String keywords_vocabulary "GCMD Science Keywords";
    String license 
"The data may be used and redistributed for free but is not intended
for legal use, since it may contain inaccuracies. Neither the data
Contributor, ERD, NOAA, nor the United States Government, nor any
of their employees or contractors, makes any warranty, express or
implied, including warranties of merchantability and fitness for a
particular purpose, or assumes any legal liability for the accuracy,
completeness, or usefulness, of this information.";
    String location "Proto fmrc:HFRADAR_US_East_and_Gulf_Coast_2km_Resolution_Hourly_RTV";
    String naming_authority "edu.ucsd.cordc";
    Float64 Northernmost_Northing 46.49442;
    String processing_level 
"Near real-time dataset with automated data acquisition and processing 
quality control";
    String product_version "2.0.00";
    String program "Integrated Ocean Observing System (IOOS)";
    String references 
"Terrill, E. et al., 2006. Data Management and Real-time Distribution 
in the HF-Radar National Network. Proceedings of the MTS/IEEE Oceans 
2006 Conference, Boston MA, September 2006.";
    String source "surface ocean velocity field from hf-radar";
    String sourceUrl "https://hfrnet-tds.ucsd.edu/thredds/dodsC/HFR/USEGC/2km/hourly/RTV/HFRADAR_US_East_and_Gulf_Coast_2km_Resolution_Hourly_RTV_best.ncd";
    Float64 Southernmost_Northing 21.7;
    String standard_name_vocabulary "CF Standard Name Table v70";
    String summary 
"Surface ocean velocities estimated from HF-Radar are representative 
of the upper 1.0 meters of the ocean.  The main objective of 
near-real time processing is to produce the best product from 
available data at the time of processing.  Radial velocity 
measurements are obtained from individual radar sites through the 
U.S. HF-Radar Network. Hourly radial data are processed by unweighted 
least squares on a 2km resolution grid of the U.S. East and Gulf 
Coast to produce near real-time surface current maps.";
    String testOutOfDate "now-1day";
    String time_coverage_end "2024-11-21T09:00:00Z";
    String time_coverage_start "2012-01-01T00:00:00Z";
    String title "Currents, HF Radar, US East Coast and Gulf of Mexico, RTV, Near-Real Time, 2012-present, Hourly, 2km";
    Float64 Westernmost_Easting -97.88385;
  }
}

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.

ERDDAP, Version 2.25_1
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