N: 66.15 S: -66.15 E: 180 W: -180
Description
Provides L2 high resolution (HR) short time critical (STC; 36-hour latency) altimetry from the Poseidon-4 SAR altimeter on the Sentinel-6A Michael Freilich spacecraft. It contains Sea Surface Height (SSH), Sea Surface Height Anomalies (SSHA) and Significant Wave Height (SWH), along with 1 Hz and 20 Hz Ku-band measurements processed from L1B altimetry including the range, orbital altitude, time, and water vapour. It also includes altimetry corrections, significant wave height and wind-speed from the AMR-C. This standard product release provides the geophysical parameters at both 1 and 20 Hz. The S6A STC product is analogous to the Jason-3 IGDR product.
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Variables
The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.
For questions on a specific variable, please use the Earthdata Forum.
| Name Sort descending | Description | Units | Data Type | Fill Value | Valid Range | Scale Factor | Offset |
|---|---|---|---|---|---|---|---|
| /data_01/rad_wind_speed_qual | Quality flag for the radiometer wind speed | N/A | byte | 127 | N/A | 1 | N/A |
| /data_01/rain_attenuation | Difference between the expected Ku-band backscatter coefficient (based on the C-band backscatter coefficient) and the measured Ku-band backscatter coefficient | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_01/rain_flag | Rain flag derived from altimeter measurements | N/A | byte | 127 | N/A | 1 | N/A |
| /data_01/solid_earth_tide | Calculated using Cartwright and Tayler tables and consisting of the second and third degree constituents. The permanent tide (zero frequency) is not included | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_01/surface_classification_flag | 7-state surface type classification from MODIS and GlobCover | N/A | byte | 127 | N/A | 1 | N/A |
| /data_01/time | It contains the seconds since 1 Jan 2000 00:00:00. Time is in UTC. Time refers to the instant the L1B waveform (which is a combination of echoes for both LR and HR) touches the surface. Whenever a leap second occurs, the attribute leap_second will be set to the appropriate value | seconds since 2000-01-01 00:00:00.0 | double | N/A | N/A | 1 | N/A |
| /data_01/time_tai | Time of measurement in seconds in the TAI time scale since 1 Jan 2000 00:00:00 TAI. This time scale contains no leap seconds. The difference (in seconds) with time in UTC is given by the attribute [time:tai_utc_difference]. | seconds since 2000-01-01 00:00:00.0 | double | N/A | N/A | 1 | N/A |
| /data_01/total_electron_content | Altimeter-derived total electron content in electrons/m^2. 1 TECU = 10^16 electrons/m^2. | m^-2 | short | 32767 | N/A | 1000000000000000 | N/A |
| /data_01/wind_speed_alt | Wind speed at 10 m height derived from altimeter measurements. A calibration bias of +0.000 dB has been added to the Ku-band backscatter coefficient (sig0_ocean) before computing the wind speed. Should not be used over land. | m/s | short | 32767 | N/A | 0.01 | N/A |
| /data_01/wind_speed_mod_u | Wind U-component interpolated under the satellite track. Computed at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag | m/s | short | 32767 | N/A | 0.01 | N/A |
| /data_01/wind_speed_mod_v | Wind V-component interpolated under the satellite track. Computed at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag | m/s | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/altitude | Altitude of the satellite center of mass above the reference ellipsoid (WGS84). | m | int | 2147483647 | N/A | 0.0001 | 1300000 |
| /data_20/ku/altitude_rate | Instantaneous altitude rate of the satellite center of mass with respect to the reference ellipsoid (WGS84) | m/s | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/ku/altitude_rate_mean_sea_surface | Instantaneous altitude rate of the satellite center of mass with respect to the mean sea surface | m/s | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/ku/amplitude_ocean | Waveform amplitude derived from the ocean retracker | 1 | int | 2147483647 | N/A | 0.001 | N/A |
| /data_20/ku/amplitude_ocog | Waveform amplitude derived from the OCOG retracker | 1 | int | 2147483647 | N/A | 0.001 | N/A |
| /data_20/ku/angle_of_approach_to_coast | Angle of approach to the closest coast. 0 is parallel to the coast with the land on the right. Positive values indicate the satellite is approaching the land. Negative values indicate the satellite is leaving the land. Values close to +/-180 degrees have the land on the left. | degrees | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/delta_ellipsoid_tp_wgs84 | Height difference between TOPEX ellipsoid and WGS84 ellipsoid. To convert heights in this product to be relative to the TOPEX ellipsoid, substract delta_ellipsoid_tp_wgs84. | m | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/ku/distance_to_coast | Distance to the closest coast | m | short | 32767 | N/A | 100 | N/A |
| /data_20/ku/echo_avg_numval | Number of single looks averaged into the 20 Hz L1B waveform. | 1 | short | 32767 | N/A | 1 | N/A |
| /data_20/ku/epoch_ocean | Retracking offset (in terms of 2-way time delay) from the middle of the range window (sample 128, counting from 0) derived from the ocean retracker | s | int | 2147483647 | N/A | 1.0E-15 | N/A |
| /data_20/ku/epoch_ocog | Retracking offset (in terms of 2-way time delay) from the middle of the range window (sample 128, counting from 0) derived from the OCOG retracker. | s | int | 2147483647 | N/A | 1.0E-15 | N/A |
| /data_20/ku/geoid | Height of the geoid above the reference ellipsoid (WGS84) computed from the model with a correction to refer the value to the mean tide system i.e. includes the permanent tide (zero frequency). | m | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/ku/index_1hz_measurement | Level 2 record counter of the averaged 1 Hz measurement associated to the 20 Hz elementary measurement | 1 | int | 2147483647 | N/A | 1 | N/A |
| /data_20/ku/internal_tide | Internal tide prediction from the HRET model. This only includes the so-called static harmonic components. It is not included as a correction to the sea surface height, but users can use it to remove the internal tide from the sea surface height anomaly | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/l1b_record_counter | This is the Level 1B record counter. Starting from 0 for each Level 1B product | 1 | int | 2147483647 | N/A | 1 | N/A |
| /data_20/ku/l2_record_counter | This is the Level 2 record counter. Starting from 0 for each Level 2 product | 1 | int | 2147483647 | N/A | 1 | N/A |
| /data_20/ku/latitude | Latitude of measurement [-90, +90]. Positive latitude is North latitude, negative latitude is South latitude | degrees_north | int | 2147483647 | N/A | 1.0E-6 | N/A |
| /data_20/ku/load_tide_sol1 | This value has already been added to the corresponding ocean tide height value recorded in the product (ocean_tide_sol1) | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/load_tide_sol2 | This value contains the total load tide height (short-period and long-period) for the geocentric ocean tide (solution 2). To get only the pure ocean tide height (solution 2), do: ocean_tide_sol2 + ocean_tide_non_eq - load_tide_sol2. This value has already been added to the corresponding ocean tide height value recorded in the product (ocean_tide_sol2) | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/longitude | Longitude of measurement [0, 360). East longitude relative to Greenwich meridian | degrees_east | int | 2147483647 | N/A | 1.0E-6 | N/A |
| /data_20/ku/manoeuvre_flag | Maneuvre flags contained within the NAVATT file | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/mean_sea_surface_sol1 | Mean sea surface height solution 1 above reference ellipsoid (WGS84) | m | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/ku/mean_sea_surface_sol1_acc | Mean sea surface height (solution 1) accuracy | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/mean_sea_surface_sol1_qual | Interpolation flag (good or bad) for the mean sea surface solution 1 | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/mean_sea_surface_sol2 | Mean sea surface height solution 2 above reference ellipsoid (WGS84) | m | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/ku/mean_sea_surface_sol2_acc | Mean sea surface height (solution 2) accuracy | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/mean_sea_surface_sol2_qual | Interpolation flag (good or bad) for the mean sea surface solution 2 | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/meteo_map_availability_flag | Possible values are: 0 meaning '2 maps, nominal' (six hours apart), 1 meaning '1 map, extrapolation used', 2 meaning 'no map' | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/model_dry_tropo_cor_measurement_altitude | Dry troposphere correction. Computed from 3d meteorological fields at measurement altitude, at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. A dry tropospheric correction must be added (negative value) to the instrument range measurement to correct it for the dry tropospheric delay of the radar pulse | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/model_dry_tropo_cor_zero_altitude | Dry troposphere correction. Computed from 3d meteorological fields at measurement altitude, at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. A dry tropospheric correction must be added (negative value) to the instrument range measurement to correct it for the dry tropospheric delay of the radar pulse | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/model_wet_tropo_cor_measurement_altitude | Wet troposphere correction. Computed from 3d meteorological fields at measurement altitude, at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. A wet tropospheric correction must be added (negative value) to the instrument range measurement to correct it for the wet tropospheric delays of the radar pulse | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/model_wet_tropo_cor_zero_altitude | Wet troposphere correction. Computed from 3d meteorological fields at measurement altitude, at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. A wet tropospheric correction must be added (negative value) to the instrument range measurement to correct it for the wet tropospheric delays of the radar pulse | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/mqe_ocean | Mean quadratic error between the waveform and the model from the ocean retracker after normalisation by the waveform amplitude | 1 | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/ku/net_instr_cor_range_ocean | Sum of all Instrumental corrections on the altimeter range: USO drift (L1B range_cor_uso) + internal path delay (L1B range_cor_internal_delay_cal and range_cor_internal_delay_diff) + external path delay (L1B range_cor_external_group_delay) + distance antenna-COG (L1B range_cor_com) + Doppler correction (L2 range_cor_doppler) + modeled instrumental errors correction (L2 model_instr_cor_range_ocean) + system bias | m | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/ku/net_instr_cor_sig0_ocean | Sum of all Instrumental corrections on the backscatter coefficient: all calibrated instrument gains (L1B power_scaling_to_antenna) + modeled instrumental errors correction (L2 model_instr_cor_sig0_ocean) + system bias. The atmospheric attenuation correction is not included. | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/net_instr_cor_swh_ocean | Sum of all Instrumental corrections on the significant wave height: modeled instrumental errors correction and system bias | m | short | 32767 | N/A | 0.001 | N/A |
| /data_20/ku/noise_floor_ocean | Thermal noise estimate | 1 | int | 2147483647 | N/A | 0.001 | N/A |
| /data_20/ku/num_iterations_ocean | Number of fitting iterations for the ocean retracker | 1 | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/ocean_geo_corrections | Sum of meteorological and geophysical corrections to be applied to SSHA over ocean: altimeter ionospheric correction (iono_cor_alt_filtered) + model dry tropospheric correction at zero altitude (model_dry_tropo_cor_zero_altitude) + radiometer wet tropospheric correction (rad_wet_tropo) + sea state bias correction (sea_state_bias) + solid earth tide height (solid_earth_tide) + geocentric ocean tide height solution 2 (FES) (ocean_tide_sol2) + internal tide (internal_tide) + geocentric pole tide height (pole_tide) + dynamic atmospheric correction (dac for NTC/STC off line products, inv_bar_cor for NRT products) | m | int | 2147483647 | N/A | 0.0001 | N/A |