N: 66.15 S: -66.15 E: 180 W: -180
Description
Provides low resolution (LR) short time critical (STC; 36-hour latency) measurements of sea surface height anomaly (SSHA), Significant Wave Height (SWH), and Wind Speed, along with 1 Hz and 20 Hz measurements from the radar altimeter, orbit altitude, environmental range corrections, instrument corrections, and geophysical models. The STC product is analogous to the Jason-3 IGDR product.
Product Summary
Citation
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
Copy Citation
Documents
DATA CITATION GUIDELINES
GENERAL DOCUMENTATION
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_water_vapor_qual | Quality flag for the radiometer water vapor content | N/A | byte | 127 | N/A | 1 | N/A |
| /data_01/rad_wet_tropo_cor | Wet tropospheric correction derived from the on-board radiometer and valid over ocean surfaces only. 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_01/rad_wet_tropo_cor_qual | Quality flag for the radiometer wet troposphere correction | N/A | byte | 127 | N/A | 1 | N/A |
| /data_01/rad_wind_speed | Wind speed at 10 m height derived from radiometer measurements. | m/s | short | 32767 | N/A | 0.01 | N/A |
| /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_alt_mle3 | Wind speed at 10 m height derived from altimeter MLE3 measurements. A calibration bias of +0.000 dB has been added to the Ku-band backscatter coefficient (sig0_ocean_mle3) 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/c/altitude | Altitude of the satellite center of mass above the reference ellipsoid (WGS84). | m | int | 2147483647 | N/A | 0.0001 | 1300000 |
| /data_20/c/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/c/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/c/amplitude_ocean | Waveform amplitude derived from the ocean retracker | 1 | int | 2147483647 | N/A | 0.001 | N/A |
| /data_20/c/amplitude_ocog | Waveform amplitude derived from the OCOG retracker | 1 | int | 2147483647 | N/A | 0.001 | N/A |
| /data_20/c/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/c/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/c/distance_to_coast | Distance to the closest coast | m | short | 32767 | N/A | 100 | N/A |
| /data_20/c/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/c/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/c/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/c/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/c/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/c/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/c/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/c/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/c/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) + 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/c/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/c/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/c/noise_floor_ocean | Thermal noise estimate | 1 | int | 2147483647 | N/A | 0.001 | N/A |
| /data_20/c/num_iterations_ocean | Number of fitting iterations for the ocean retracker | 1 | byte | 127 | N/A | 1 | N/A |
| /data_20/c/p4_mode_flag | Flag containing the mode identifier from the P4 instrument source packets | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/c/range_cor_doppler | Doppler correction computed with respect to the mean sea surface / geoid. It is applied to the altimeter range | m | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/c/range_ocean | Range computed from the ocean retracker. It includes all instrumental corrections from net_instr_cor_range_ocean | m | int | 2147483647 | N/A | 0.0001 | 1300000 |
| /data_20/c/range_ocean_qual | Flag indicating the use or not of the 20 Hz ocean altimeter range estimate in the computation of the 1 Hz estimate (map of compression) | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/c/range_ocog | Corrected OCOG altimeter range. This includes the instrumental corrections in tracker_range_calibrated. | m | int | 2147483647 | N/A | 0.0001 | 1300000 |
| /data_20/c/range_oversampling_factor | The instrument samples the waveforms with a 395 MHz clock, providing a nominal_sampling = c / 395e6 / 2 = ~0.379m (with c=speed of light). In addition, the ground processor can apply an oversampling factor, providing a waveform_sampling = nominal_sampling / range_oversampling_factor. Note that the altimeter range resolution is fixed and given by the chirp bandwidth of 320 MHz: c / 320e6 / 2 = ~0.468m | 1 | byte | 127 | N/A | 1 | N/A |
| /data_20/c/sig0_ocean | Backscatter coefficient computed from the ocean retracker. It includes all instrumental corrections from net_instr_cor_sig0_ocean and sig0_scaling_factor as well as the atmospheric attenuation correction. | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/sig0_ocean_qual | Flag indicating the use or not of the 20 Hz estimate of the ocean backscatter coefficient in the computation of the 1 Hz estimate (map of compression) | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/c/sig0_ocog | Backscatter coefficient computed from OCOG retracking. It includes all calibrated instrument gains from L1B power_scaling_to_antenna plus geometry and antenna gain from sig0_scaling_factor | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/sig0_scaling_factor | The scaling factor in order to retrieve sigma-0 from L1B waveform. It includes the antenna gains and all the geometry factors satellite-surface, according to the radar equation. It is not applied to the L1B waveforms. | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/sigmac_ocean | Composite sigma derived from the ocean retracker | s | int | 2147483647 | N/A | 1.0E-15 | N/A |
| /data_20/c/swh_ocean | SWH computed from the ocean retracker. It includes all instrumental corrections from net_instr_cor_swh_ocean | m | short | 32767 | N/A | 0.001 | N/A |
| /data_20/c/swh_ocean_qual | Flag indicating the use or not of the 20 Hz estimate of the ocean significant waveheight in the computation of the 1 Hz estimate (map of compression) | N/A | byte | 127 | N/A | 1 | N/A |