Data Access Form

Dataset Title:	HF radar - reprocessed data - Global Ocean, near-surface zonal and meridional velocities
Institution:	MIO UMR 7294 CNRS - Marseille (Dataset ID: GL_TV_HF_HFR-MedTln)
Information:	Summary \| License \| FGDC \| ISO 19115 \| Metadata \| Background \| Subset \| 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.

Variable

Optional
Constraint #1

Optional
Constraint #2

Minimum

or a List of Values

Maximum

latitude (degrees_north)

42.1

43.05414

longitude (degrees_east)

5.7

6.805672

time (UTC)

crs

SDN_CRUISE (Grid grouping label)

SDN_STATION (Grid label)

SDN_LOCAL_CDI_ID (SeaDataNet CDI identifier)

SDN_REFERENCES (Usage metadata reference)

depth (m)

EWCT (m s-1)

-1.5

1.5

NSCT (m s-1)

-1.5

1.499

UACC (m s-1)

VACC (m s-1)

GDOP (1)

4.0

32.766

TIME_QC (Time quality flag, 1)

POSITION_QC (Position quality flag, 1)

DEPH_QC (Depth quality flag, 1)

QCflag (Overall quality flag, 1)

VART_QC (1)

GDOP_QC (GDOP threshold quality flag, 1)

DDNS_QC (1)

CSPD_QC (1)

NARX (Number of receive antennas, 1)

NATX (Number of transmit antennas, 1)

Server-side Functions

distinct()

Hover here to see a list of options. Click on an option to select it.

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 {
 s {
  latitude {
    String _CoordinateAxisType "Lat";
    Float32 actual_range 42.1, 43.05414;
    String ancillary_variables "POSITION_QC";
    String axis "Y";
    Float64 colorBarMaximum 90.0;
    Float64 colorBarMinimum -90.0;
    String ioos_category "Location";
    String long_name "Latitude of each location";
    String sdn_P02_urn "SDN:P02::ALAT";
    String sdn_parameter_name "Latitude north";
    String sdn_parameter_urn "SDN:P01::ALATZZ01";
    String sdn_uom_name "Degrees north";
    String sdn_uom_urn "SDN:P06::DEGN";
    String standard_name "latitude";
    String units "degrees_north";
    Float32 valid_max 90.0;
    Float32 valid_min -90.0;
  }
  longitude {
    String _CoordinateAxisType "Lon";
    Float32 actual_range 5.7, 6.805672;
    String ancillary_variables "POSITION_QC";
    String axis "X";
    Float64 colorBarMaximum 180.0;
    Float64 colorBarMinimum -180.0;
    String ioos_category "Location";
    String long_name "Longitude of each location";
    String sdn_P02_urn "SDN:P02::ALAT";
    String sdn_parameter_name "Longitude east";
    String sdn_parameter_urn "SDN:P01::ALONZZ01";
    String sdn_uom_name "Degrees east";
    String sdn_uom_urn "SDN:P06::DEGE";
    String standard_name "longitude";
    String units "degrees_east";
    Float32 valid_max 180.0;
    Float32 valid_min -180.0;
  }
  time {
    String _CoordinateAxisType "Time";
    Float64 actual_range 1.3377636e+9, 1.66662714375e+9;
    String ancillary_variables "TIME_QC";
    String axis "T";
    String calendar "standard";
    Float64 colorBarMaximum 100000.0;
    Float64 colorBarMinimum -100000.0;
    String ioos_category "Time";
    String long_name "Time";
    String sdn_P02_urn "SDN:P02::AYMD";
    String sdn_parameter_name "Elapsed time (since 1950-01-01T00:00:00Z)";
    String sdn_parameter_urn "SDN:P01::ELTJLD01";
    String sdn_uom_name "Days";
    String sdn_uom_urn "SDN:P06::UTAA";
    String standard_name "time";
    String time_origin "01-JAN-1970 00:00:00";
    String units "seconds since 1970-01-01T00:00:00Z";
    Float64 valid_max 90000.0;
    Float64 valid_min -90000.0;
  }
  crs {
    Int16 _FillValue 32767;
    Int16 actual_range 0, 0;
    String epsg_code "EPSG:4326";
    String grid_mapping_name "latitude_longitude";
    Float64 inverse_flattening 298.257223563;
    String ioos_category "Unknown";
    String long_name "CRS";
    Float64 semi_major_axis 6378137.0;
  }
  SDN_CRUISE {
    String ioos_category "Unknown";
    String long_name "Grid grouping label";
  }
  SDN_STATION {
    String ioos_category "Unknown";
    String long_name "Grid label";
  }
  SDN_LOCAL_CDI_ID {
    String cf_role "grid_id";
    String ioos_category "Identifier";
    String long_name "SeaDataNet CDI identifier";
  }
  SDN_REFERENCES {
    String ioos_category "Unknown";
    String long_name "Usage metadata reference";
  }
  depth {
    String _CoordinateAxisType "Height";
    String _CoordinateZisPositive "down";
    Float32 _FillValue 9.96921e+36;
    Float32 actual_range 0.0, 0.0;
    String ancillary_variables "DEPH_QC";
    String axis "Z";
    Float64 colorBarMaximum 8000.0;
    Float64 colorBarMinimum -8000.0;
    String colorBarPalette "TopographyDepth";
    String data_mode "R";
    String ioos_category "Location";
    String long_name "Depth";
    String positive "down";
    String references "sea_level";
    String sdn_P02_urn "SDN:P02::AHGT";
    String sdn_parameter_name "Depth below surface of the water body";
    String sdn_parameter_urn "SDN:P01::ADEPZZ01";
    String sdn_uom_name "Metres";
    String sdn_uom_urn "SDN:P06::ULAA";
    String source_name "DEPH";
    String standard_name "depth";
    String units "m";
    Float32 valid_max 12000.0;
    Float32 valid_min -12000.0;
  }
  EWCT {
    Float64 _FillValue -32.767;
    Float64 actual_range -1.5, 1.5;
    String ancillary_variables "QCflag VART_QC CSPD_QC DDNS_QC GDOP_QC";
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String data_mode "R";
    String ioos_category "Currents";
    String long_name "West-east current component";
    String sdn_P02_urn "SDN:P02::RFVL";
    String sdn_parameter_name "Eastward current velocity in the water body";
    String sdn_parameter_urn "SDN:P01::LCEWZZ01";
    String sdn_uom_name "Metres per second";
    String sdn_uom_urn "SDN:P06::UVAA";
    String standard_name "eastward_sea_water_velocity";
    String units "m s-1";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  NSCT {
    Float64 _FillValue -32.767;
    Float64 actual_range -1.5, 1.499;
    String ancillary_variables "QCflag VART_QC CSPD_QC DDNS_QC GDOP_QC";
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String data_mode "R";
    String ioos_category "Currents";
    String long_name "South-north current component";
    String sdn_P02_urn "SDN:P02::RFVL";
    String sdn_parameter_name "Northward current velocity in the water body";
    String sdn_parameter_urn "SDN:P01::LCNSZZ01";
    String sdn_uom_name "Metres per second";
    String sdn_uom_urn "SDN:P06::UVAA";
    String standard_name "northward_sea_water_velocity";
    String units "m s-1";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  UACC {
    Float64 _FillValue -32.767;
    String ancillary_variables "QCflag VART_QC";
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String data_mode "R";
    String ioos_category "Currents";
    String long_name "Accuracy of surface eastward sea water velocity";
    String sdn_uom_name "Metres per second";
    String sdn_uom_urn "SDN:P06::UVAA";
    String standard_name "eastward_sea_water_velocity";
    String units "m s-1";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  VACC {
    Float64 _FillValue -32.767;
    String ancillary_variables "QCflag VART_QC";
    Float64 colorBarMaximum 0.5;
    Float64 colorBarMinimum -0.5;
    String data_mode "R";
    String ioos_category "Currents";
    String long_name "Accuracy of surface northward sea water velocity";
    String sdn_uom_name "Metres per second";
    String sdn_uom_urn "SDN:P06::UVAA";
    String standard_name "northward_sea_water_velocity";
    String units "m s-1";
    Float64 valid_max 10.0;
    Float64 valid_min -10.0;
  }
  GDOP {
    Float64 _FillValue -32.767;
    Float64 actual_range 4.0, 32.766;
    String ancillary_variables "QCflag GDOP_QC";
    Float64 colorBarMaximum 0.1;
    Float64 colorBarMinimum 0.0;
    String comment "The Geometric Dilution of Precision (GDOP) is the coefficient of the uncertainty, which relates the uncertainties in radial and velocity vectors. The GDOP is a unit-less coefficient, which characterizes the effect that radar station geometry has on the measurement and position determination errors. A low GDOP corresponds to an optimal geometric configuration of radar stations, and results in accurate surface current data. Essentially, GDOP is a quantitative way to relate the radial and velocity vector uncertainties. Setting a threshold on GDOP for total combination avoids the combination of radials with an intersection angle below a certain value. GDOP is a useful metric for filtering errant velocities due to poor geometry.";
    String data_mode "R";
    String ioos_category "Statistics";
    String long_name "Geometrical dilution of precision";
    Float64 missing_value 32.767;
    String sdn_uom_name "Dimensionless";
    String sdn_uom_urn "SDN:P06::UUUU";
    String units "1";
    Float64 valid_max 20.0;
    Float64 valid_min -20.0;
  }
  TIME_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 0, 0;
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "OceanSITES quality flagging for temporal coordinate.";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String ioos_category "Quality";
    String long_name "Time quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  POSITION_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 2, 9;
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "OceanSITES quality flagging for position coordinates.";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String ioos_category "Quality";
    String long_name "Position quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  DEPH_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 0, 0;
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "OceanSITES quality flagging for depth coordinate.";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String ioos_category "Quality";
    String long_name "Depth quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  QCflag {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 3, 9;
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "OceanSITES quality flagging for all QC tests.";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String ioos_category "Quality";
    String long_name "Overall quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  VART_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 0, 0;
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "OceanSITES quality flagging for variance threshold QC test. Threshold set to 5 m2/s2.";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String ioos_category "Statistics";
    String long_name "Variance threshold quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  GDOP_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 1, 9;
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "OceanSITES quality flagging for GDOP threshold QC test. Threshold set to 5.";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String ioos_category "Quality";
    String long_name "GDOP threshold quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  DDNS_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 1, 9;
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "OceanSITES quality flagging for Data density threshold QC test. Threshold set to 2 radials.";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String ioos_category "Quality";
    String long_name "Data density threshold quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  CSPD_QC {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 1, 9;
    Float64 colorBarMaximum 10.0;
    Float64 colorBarMinimum 0.0;
    String comment "OceanSITES quality flagging for Velocity threshold QC test. Threshold set to 1.5 m/s.";
    String flag_meanings "no_qc_performed good_data probably_good_data bad_data_that_are_potentially_correctable bad_data value_changed value_below_detection nominal_value interpolated_value missing_value";
    Byte flag_values 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;
    String ioos_category "Quality";
    String long_name "Velocity threshold quality flag";
    String units "1";
    Byte valid_max 9;
    Byte valid_min 0;
  }
  NARX {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 2, 2;
    Float64 colorBarMaximum 100.0;
    Float64 colorBarMinimum 0.0;
    String data_mode "R";
    String ioos_category "Statistics";
    String long_name "Number of receive antennas";
    String sdn_uom_name "Dimensionless";
    String sdn_uom_urn "SDN:P06::UUUU";
    String units "1";
    Byte valid_max 127;
    Byte valid_min 0;
  }
  NATX {
    Byte _FillValue -127;
    String _Unsigned "false";
    Byte actual_range 2, 2;
    Float64 colorBarMaximum 100.0;
    Float64 colorBarMinimum 0.0;
    String data_mode "R";
    String ioos_category "Statistics";
    String long_name "Number of transmit antennas";
    String sdn_uom_name "Dimensionless";
    String sdn_uom_urn "SDN:P06::UUUU";
    String units "1";
    Byte valid_max 127;
    Byte valid_min 0;
  }
 }
  NC_GLOBAL {
    String area "Mediterranean Sea";
    String calibration_link "Dylan Dumas, Charles-Antoine Guerin, Self-calibration and antenna grouping for bistatic oceanographic High-Frequency Radars,2020, https://arxiv.org/abs/2005.10528";
    String calibration_type "POB: internal; PEY: internal";
    String cdm_data_type "Grid";
    String citation "These data were collated within the Copernicus Marine Service (In Situ) and EMODnet collaboration framework. Data is made freely available by the Copernicus Marine Service and the programs that contribute to it.";
    String comment "Total velocities are derived using least square fit that maps radial velocities measured from individual sites onto a cartesian grid. The final product is a map of the horizontal components of the ocean currents on a regular grid in the area of overlap of two or more radar stationsradials data are processing with hybrid BD/DF method with ...";
    String Conventions "CF-1.11, Copernicus-InSituTAC-FormatManual-2.0.0, Copernicus-InSituTAC-ParametersList-3.3.0, Copernicus-InSituTAC-AttributesList-1.0.0, COARDS, ACDD-1.3";
    String creator_name "MIO UMR7294 / OSU Pytheas";
    String creator_type "institution";
    String creator_url "https://dataset.osupytheas.fr/geonetwork/srv/fre/catalog.search#/metadata/GL_TV_HF_HFR-MedTln-Total-reprocessed";
    String data_mode "R";
    String date_created "2024-06-05T14:59:44Z";
    String date_modified "2024-06-05T14:59:44Z";
    String doa_estimation_method "Direction Finding";
    Float64 Easternmost_Easting 6.805672;
    String format_version "2.0";
    Float64 geospatial_lat_max 43.05414;
    Float64 geospatial_lat_min 42.1;
    String geospatial_lat_units "degrees_north";
    Float64 geospatial_lon_max 6.805672;
    Float64 geospatial_lon_min 5.7;
    String geospatial_lon_units "degrees_east";
    Float64 geospatial_vertical_max 0.0;
    Float64 geospatial_vertical_min 0.0;
    String geospatial_vertical_positive "down";
    String geospatial_vertical_units "m";
    String grid_mapping_epsg_code "EPSG:4326";
    Float64 grid_mapping_inverse_flattening 298.257223563;
    String grid_mapping_name "latitude_longitude";
    Float64 grid_mapping_semi_major_axis 6378137.0;
    String history 
"2022-10-22T17:00:00Z data collected. 2024-06-05T14:59:44Z netCDF file created and sent to OSU Pytheas datasets
2024-10-18T06:26:15Z (local files)
2024-10-18T06:26:15Z http://erddap.osupytheas.fr/erddap/tabledap/GL_TV_HF_HFR-MedTln.html";
    String id "GL_TV_HF_HFR-MedTln-Total_20221022";
    String infoUrl "https://dataset.osupytheas.fr/geonetwork/srv/fre/catalog.search#/metadata/GL_TV_HF_HFR-MedTln-Total-reprocessed";
    String institution "MIO UMR 7294 CNRS - Marseille";
    String institution_country "France";
    String institution_edmo_code "3078";
    String institution_references "https://www.mio.osupytheas.fr/";
    String keywords "accuracy, active, antennas, atlantic, based, cdi, circulation, cnrs, component, crs, CSPD_QC, current, currents, data, DDNS_QC, density, DEPH_QC, depth, dilution, driven, earth, Earth Remote Sensing Instruments > Active Remote Sensing > Imaging Radars, Earth Science > Oceans > Ocean Circulation > Ocean Currents, Earth Science > Oceans > Ocean Circulation > Wind-Driven Circulation, east, eastward, eastward_sea_water_velocity, EWCT, flag, frequency, gdop, GDOP_QC, geometrical, global, grid, grouping, HF, hf radar, hf radio, hfr, hfradar, hfradio, high, identifier, imaging, In Situ Land-based Platforms > Observatories, In Situ Land-based Platforms > Radio transmitters, institute, instruments, label, land, land-based, latitude, longitude, marseille, measured, mediterranean, meridional, metadata, mio, NARX, NATX, near, near-surface, north, northward, northward_sea_water_velocity, NSCT, number, observatories, ocean, OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > MEDITERRANEAN SEA, ocean > sea_surface_skin, oceanography, oceans, oceean, overall, platforms, position, POSITION_QC, precision, QCflag, quality, radar, radars, radio, raw, receive, reference, remote, science, SDN_CRUISE, SDN_LOCAL_CDI_ID, SDN_REFERENCES, SDN_STATION, sea, seadatanet, seawater, sensing, situ, skin, south, south-north, statistics, surface, threshold, time, TIME_QC, transmit, transmitters, UACC, umr, usage, VACC, variance, VART_QC, velocities, velocity, water, west, west-east, wind, wind-driven, zonal";
    String keywords_vocabulary "GCMD Science Keywords";
    String last_calibration_date "2022-10-22T17:00:00Z";
    String license "https://marine.copernicus.eu/user-corner/service-commitments-and-licence";
    String naming_authority "Copernicus Marine In Situ";
    String netcdf_version "netCDF-4 classic model";
    Float64 Northernmost_Northing 43.05414;
    String platform_code "HFR-MedTln-Total";
    String platform_name "HFR-MedTln-Total";
    String processing_level "3A";
    String project "SINAPSI (13668), SICOMAR PLUS(12402), IMPACT(12271), MOOSE(11574), and JERICO NEXT(12227)";
    String publisher_email "cmems-service@ifremer.fr";
    String publisher_institution "European HFR Node";
    String publisher_name "Copernicus Marine Service";
    String publisher_url "https://dataset.osupytheas.fr/";
    String references "http://marine.copernicus.eu http://www.marineinsitu.eu http://www.marineinsitu.eu/wp-content/uploads/2018/02/HFR_Data_Model_Reference_Card_v1.pdf";
    String site_code "HFR-MedTln";
    String source "coastal structure";
    String source_platform_category_code "17";
    String sourceUrl "(local files)";
    Float64 Southernmost_Northing 42.1;
    String standard_name_vocabulary "CF Standard Name Table v70";
    String subsetVariables "time, crs, SDN_CRUISE, SDN_STATION, SDN_LOCAL_CDI_ID, SDN_REFERENCES, depth, UACC, VACC, TIME_QC, DEPH_QC, VART_QC, NARX, NATX";
    String summary 
"Global Ocean - near-surface zonal and meridional raw velocities measured by High Frequency radars. Hourly High Frequency Radar (HFR) surface current data (ocean surface vel
ocity) from 2 different stations located on the French Mediterranean coast (Toulon), reprocessed.";
    String time_coverage_end "2022-10-24T15:59:03Z";
    String time_coverage_start "2012-05-23T09:00:00Z";
    String title "HF radar - reprocessed data - Global Ocean, near-surface zonal and meridional velocities";
    String update_interval "void";
    Float64 Westernmost_Easting 5.7;
  }
}

Using tabledap to Request Data and Graphs from Tabular Datasets

tabledap lets you request a data subset, a graph, or a map from a tabular dataset (for example, buoy data), via a specially formed URL. tabledap uses the OPeNDAP (external link)

Data Access Protocol (DAP) (external link)

and its selection 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 or Subset form. They make 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.

Tabledap request URLs must be in the form
https://coastwatch.pfeg.noaa.gov/erddap/tabledap/datasetID.fileType{?query}
For example,
https://coastwatch.pfeg.noaa.gov/erddap/tabledap/pmelTaoDySst.htmlTable?longitude,latitude,time,station,wmo_platform_code,T_25&time>=2015-05-23T12:00:00Z&time<=2015-05-31T12:00:00Z
Thus, the query is often a comma-separated list of desired variable names, followed by a collection of constraints (e.g., variable<value), each preceded by '&' (which is interpreted as "AND").

For details, see the tabledap Documentation.