N: 77.6 S: -77.6 E: 180 W: -180
Description
Same as L2_NALT_GDR, using preliminary values for some auxiliary data. Uses Medium-accuracy (preliminary) Orbit Ephemeris (MOE). Available with latency of < 1.5 days. Discrete measurements at nadir for each half orbit, along the ground track. Available in netCDF-4 file format.
This collection is a sub-collection of its parent: https://podaac.jpl.nasa.gov/dataset/SWOT_L2_NALT_IGDR_D
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Citation
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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/surface_slope_cor | The surface slope correction model aims to improve the accuracy of mean sea surface topography models as well as marine gravity models. See SWOT Nadir Altimeter User Handbook | m | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_01/time | Time of measurement in seconds in the UTC time scale since 1 Jan 2000 00:00:00 UTC. [tai_utc_difference] is the difference between TAI and UTC reference time (seconds) for the first measurement of the data set. If a leap second occurs within the data set, the attribute [leap_second] is set to the UTC time at which the leap second occurs | 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 | 1.844674407371E+19 | N/A | 1 | N/A |
| /data_01/wave_model_interp_qual | 0 = interpolation from 4 points; 1 = interpolation from less than 4 points | N/A | byte | 127 | N/A | 1 | N/A |
| /data_01/wave_model_map_availability_flag | Possible values are: 0 meaning ’2 maps, nominal’ (three hours apart), 1 meaning ’2 maps, degraded’ (more than three hours apart), 2 meaning ’1 map, closest map used’, 3 meaning ’no valid map’ | N/A | byte | 127 | N/A | 1 | N/A |
| /data_01/wind_speed_alt | Should not be used over land. See SWOT Nadir Altimeter User Handbook. A calibration bias of +0.39 dB has been added to the Ku band backscatter coefficient (/data_01/ku/sig0_ocean) before computing the wind speed | m/s | short | 32767 | N/A | 0.01 | N/A |
| /data_01/wind_speed_alt_adaptive | Should not be used over land. See SWOT Nadir Altimeter User Handbook. A calibration bias of +0.08 dB has been added to the Ku band backscatter coefficient (/data_01/ku/sig0_adaptive) before computing the wind speed | m/s | short | 32767 | N/A | 0.01 | N/A |
| /data_01/wind_speed_alt_mle3 | Should not be used over land. See SWOT Nadir Altimeter User Handbook. A calibration bias of +0.109 dB has been added to the Ku band backscatter coefficient (/data_01/ku/sig0_ocean_mle3) before computing the wind speed | m/s | short | 32767 | N/A | 0.01 | N/A |
| /data_01/wind_speed_mod_u | Computed at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. See SWOT Nadir Altimeter User Handbook | m/s | short | 32767 | N/A | 0.01 | N/A |
| /data_01/wind_speed_mod_v | Computed at the altimeter time-tag from the interpolation of 2 meteorological fields that surround the altimeter time-tag. See SWOT Nadir Altimeter User Handbook | m/s | short | 32767 | N/A | 0.01 | N/A |
| /data_20/altitude | Altitude of satellite above the reference ellipsoid | m | int | 2147483647 | N/A | 0.0001 | 800000 |
| /data_20/alt_state_acq_mode_flag | 8 = autonomous acquisition / tracking, 9 = autonomous DIODE acquisition / tracking, 10 = DIODE + Digital Elevation Model tracking | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/alt_state_track_trans_flag | 20 Hz altimeter state flag: tracking automatic transition | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/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/agc | AGC is corrected for instrumental errors due to the imperfections of the on-board attenuators | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/agc_cor | Comes from AGC static characterization, and added to on-board AGC to obtain applied AGC | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/amplitude_ice2 | C band amplitude (ice-2 retracking) [FFT power unit] | count | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/c/amplitude_ocean | C band amplitude (ocean retracking) [FFT power unit] | count | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/c/amplitude_ocog | C band amplitude (OCOG retracking) [FFT power unit] | count | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/c/epoch_ice2 | C band epoch (ice-2 retracking) | s | int | 2147483647 | N/A | 1.0E-15 | N/A |
| /data_20/c/epoch_ocean | C band epoch (ocean retracking) | s | int | 2147483647 | N/A | 1.0E-15 | N/A |
| /data_20/c/epoch_ocog | C band epoch (OCOG retracking) | s | int | 2147483647 | N/A | 1.0E-15 | N/A |
| /data_20/c/ice2_qual | ice-2 retracking quality flag | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/c/mean_amplitude_ice2 | C band mean amplitude (ice-2 retracking) [FFT power unit] | count | int | 2147483647 | N/A | 0.0001 | N/A |
| /data_20/c/mqe_ice2 | Mean Quadratic Error between the waveforms samples and the corresponding model samples built from the ice-2 retracking outputs | 1 | int | 2147483647 | N/A | 1.0E-5 | N/A |
| /data_20/c/mqe_ocean | Mean Quadratic Error between the waveforms samples and the corresponding model samples built from the ocean retracking outputs | 1 | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/c/noise_floor_ice2 | C band thermal noise (ice-2 retracking) [FFT power unit] | count | int | 2147483647 | N/A | 1.0E-6 | N/A |
| /data_20/c/noise_floor_ocean | C band thermal noise (ocean retracking) [FFT power unit] | count | int | 2147483647 | N/A | 1.0E-6 | N/A |
| /data_20/c/num_iterations_ocean | 20 Hz number of iterations of the ocean retracking in C band | count | byte | 127 | N/A | 1 | N/A |
| /data_20/c/peakiness | 20 Hz peakiness on C band waveforms | 1 | int | 2147483647 | N/A | 0.001 | N/A |
| /data_20/c/power_waveform | Waveforms are corrected for the Low Pass Filter effects | count | int | 2147483647 | N/A | 0.001 | N/A |
| /data_20/c/range_ice2 | Distance antenna-COG (/data_01/range_cor_cog), USO drift correction (/data_01/range_cor_uso), internal path correction (/data_01/c/range_cor_internal_path), Doppler correction (/data_01/c/range_cor_doppler) and system bias included | m | int | 2147483647 | N/A | 0.0001 | 800000 |
| /data_20/c/range_ocean | All instrumental corrections included, i.e. distance antenna-COG (/data_01/range_cor_cog), USO drift correction (/data_01/range_cor_uso), internal path correction (/data_01/c/range_cor_internal_path), Doppler correction (/data_01/c/range_cor_doppler), modeled instrumental errors correction (/data_01/c/range_cor_ocean_model_instr) and system bias | m | int | 2147483647 | N/A | 0.0001 | 800000 |
| /data_20/c/range_ocean_compression_qual | Map of valid points used to compute the 1 Hz C band altimeter range | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/c/range_ocog | Distance antenna-COG (/data_01/range_cor_cog), USO drift correction (/data_01/range_cor_uso), internal path correction (/data_01/c/range_cor_internal_path), Doppler correction (/data_01/c/range_cor_doppler) and system bias included | m | int | 2147483647 | N/A | 0.0001 | 800000 |
| /data_20/c/sig0_ice2 | AGC instrumental errors correction and internal calibration correction (/data_01/c/sig0_cor_calibration) included | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/sig0_leading_edge_ice2 | AGC instrumental errors correction and internal calibration correction (/data_01/c/sig0_cor_calibration) included | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/sig0_ocean | All instrumental corrections included, excepted the system bias, i.e. AGC instrumental errors correction, internal calibration correction (/data_01/c/sig0_cor_calibration), modeled instrumental errors correction (/data_01/c/sig0_cor_ocean_model_instr) and atmospheric attenuation (sig0_cor_atm) | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/sig0_ocean_compression_qual | Map of valid points used to compute the 1 Hz C band backscatter coefficient | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/c/sig0_ocog | AGC instrumental errors correction and internal calibration correction (/data_01/c/sig0_cor_calibration) included | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/c/sig0_scaling_factor | This scaling factor represents the backscatter coefficient for a C band waveform amplitude equal to 1. It is a raw value accounting for AGC 20 Hz correction and internal calibration correction. All other correction are not applied (ie atmospheric attenuation, modeled instrumental errors correction and system bias) | dB | int | 2147483647 | N/A | 0.01 | N/A |
| /data_20/c/sigmac_ocean | The width of the leading edge corresponds to the so-called composite sigma (SigmaC) | s | int | 2147483647 | N/A | 1.0E-15 | N/A |
| /data_20/c/sigmal_ice2 | The width of the leading edge corresponds to the so-called composite sigma (SigmaL) | m | short | 32767 | N/A | 0.001 | N/A |
| /data_20/c/slope1_ice2 | 20 Hz slope of the first part of the logarithm of the C band trailing edge (ice-2 retracking) | s-1 | int | 2147483647 | N/A | 1 | N/A |
| /data_20/c/slope2_ice2 | 20 Hz slope of the second part of the logarithm of the C band trailing edge (ice-2 retracking) | s-1 | int | 2147483647 | N/A | 1 | N/A |
| /data_20/c/swh_ocean | All instrumental corrections included, i.e. modeled instrumental errors correction (/data_01/c/swh_cor_ocean_model_instr) and system bias | m | short | 32767 | N/A | 0.001 | N/A |
| /data_20/c/swh_ocean_compression_qual | Map of valid points used to compute the 1 Hz C band significant waveheight | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/c/tracker_range_calibrated | C band operating tracker. This includes the Distance antenna-COG (/data_01/range_cor_cog), USO drift correction (/data_01/range_cor_uso) and internal path correction (/data_01/c/range_cor_internal_path). But not the Doppler correction (/data_01/c/range_cor_doppler), modeled instrumental errors correction (/data_01/c/range_cor_ocean_model_instr) and system bias | m | int | 2147483647 | N/A | 0.0001 | 800000 |
| /data_20/distance_to_coast | 20 Hz distance to the coast | m | int | 2147483647 | N/A | 1 | N/A |
| /data_20/index_1hz_measurement | Record counter of the averaged 1 Hz measurement associated to the 20 Hz elementary measurement | N/A | int | 2147483647 | N/A | 1 | N/A |