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
Product Summary
Citation
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GENERAL DOCUMENTATION
DATA CITATION GUIDELINES
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_20/ku/sig0_ocean | All instrumental corrections included, excepted the system bias, i.e. AGC instrumental errors correction, internal calibration correction (/data_01/ku/sig0_cor_calibration), modeled instrumental errors correction (/data_01/ku/sig0_cor_ocean_model_instr) and atmospheric attenuation (sig0_cor_atm) | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/sig0_ocean_compression_qual | Map of valid points used to compute the 1 Hz Ku band backscatter coefficient | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/sig0_ocean_mle3 | All instrumental corrections included, excepted the system bias, i.e. AGC instrumental errors correction, internal calibration correction (/data_01/ku/sig0_cor_calibration), modeled instrumental errors correction (/data_01/ku/sig0_cor_ocean_mle3_model_instr) and atmospheric attenuation (sig0_cor_atm) | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/sig0_ocean_mle3_compression_qual | Map of valid points used to compute the 1 Hz Ku band backscatter coefficient | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/sig0_ocog | AGC instrumental errors correction and internal calibration correction (/data_01/ku/sig0_cor_calibration) included | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/sig0_scaling_factor | This scaling factor represents the backscatter coefficient for a Ku 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/ku/sig0_seaice | AGC instrumental errors correction and internal calibration correction (/data_01/ku/sig0_cor_calibration) included | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/sig0_tfmra | AGC instrumental errors correction and internal calibration correction (/data_01/ku/sig0_cor_calibration) included | dB | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/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/ku/sigmac_ocean_mle3 | 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/ku/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/ku/slope1_ice2 | 20 Hz slope of the first part of the logarithm of the Ku band trailing edge (ice-2 retracking) | s-1 | int | 2147483647 | N/A | 1 | N/A |
| /data_20/ku/slope2_ice2 | 20 Hz slope of the second part of the logarithm of the Ku band trailing edge (ice-2 retracking) | s-1 | int | 2147483647 | N/A | 1 | N/A |
| /data_20/ku/slope_ice2 | 20 Hz Ku band slope of the logarithm of the trailing edge for mispointing (ice-2 retracking) | s-1 | int | 2147483647 | N/A | 1 | N/A |
| /data_20/ku/swh_adaptive | No correction applied | m | short | 32767 | N/A | 0.001 | N/A |
| /data_20/ku/swh_adaptive_compression_qual | Map of valid points used to compute the 1 Hz Ku band significant waveheight | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/swh_ocean | All instrumental corrections included, i.e. modeled instrumental errors correction (/data_01/ku/swh_cor_ocean_model_instr) and system bias | m | short | 32767 | N/A | 0.001 | N/A |
| /data_20/ku/swh_ocean_compression_qual | Map of valid points used to compute the 1 Hz Ku band significant waveheight | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/swh_ocean_mle3 | All instrumental corrections included, i.e. modeled instrumental errors correction (/data_01/ku/swh_cor_ocean_mle3_model_instr) and system bias | m | short | 32767 | N/A | 0.001 | N/A |
| /data_20/ku/swh_ocean_mle3_compression_qual | Map of valid points used to compute the 1 Hz Ku band significant waveheight | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/tfmra_qual | TFMRA retracking quality flag | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/tracker_range_calibrated | Ku band operating tracker (’Diode+DEM’ or ’Median’ or ’Split-Gate’ 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/ku/range_cor_internal_path). But not the Doppler correction (/data_01/ku/range_cor_doppler), modeled instrumental errors correction (/data_01/ku/range_cor_ocean_model_instr) and system bias | m | int | 2147483647 | N/A | 0.0001 | 800000 |
| /data_20/ku/tracker_range_diode | 20 Hz Ku band tracker range from Diode+DEM | m | int | 2147483647 | N/A | 0.0001 | 800000 |
| /data_20/ku/wvf_main_class | Waveform classification : main class selected by classification neural network trained on shape features of the waveforms | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/wvf_main_class_score | Waveform classification : probability associated to the main class (between 0 and 100, 100=strongest probability) | N/A | short | 32767 | N/A | 0.01 | N/A |
| /data_20/ku/wvf_second_class | Waveform classification : second class selected by classification neural network trained on shape features of the waveforms | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/ku/wvf_second_class_score | Waveform classification : probability associated to the second class (between 0 and 100, 100=strongest probability) | N/A | short | 32767 | N/A | 0.01 | N/A |
| /data_20/latitude | Positive latitude is North latitude, negative latitude is South latitude. See SWOT Nadir Altimeter User Handbook | degrees_north | int | 2147483647 | N/A | 1.0E-6 | N/A |
| /data_20/longitude | East longitude relative to Greenwich meridian. See SWOT Nadir Altimeter User Handbook | degrees_east | int | 2147483647 | N/A | 1.0E-6 | N/A |
| /data_20/meteo_measurement_altitude_interp_qual | 0 = interpolation from 4 points; 1 = interpolation from less than 4 points | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/model_dry_tropo_cor_measurement_altitude | Set at FillValue (for O&IGDR) or computed at precise measurement altitude (for GDR) at the altimeter time-tag from the integration and the interpolation of meteorological fields (surface pressure, orography) and profiles (temperature, humidity) that surround the altimeter time-tag. A dry tropospheric correction must be added (negative value) to the instrument range to correct this range measurement for dry tropospheric range delays of the radar pulse. See SWOT Nadir Altimeter User Handbook | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/model_wet_tropo_cor_measurement_altitude | Set at FillValue (for O&IGDR) or computed at precise measurement altitude (for GDR) at the altimeter time-tag from the integration and the interpolation of meteorological fields (surface pressure, orography) and profiles (temperature, humidity) that surround the altimeter time-tag. A wet tropospheric correction must be added (negative value) to the instrument range to correct this range measurement for wet tropospheric range delays of the radar pulse. See SWOT Nadir Altimeter User Handbook | m | short | 32767 | N/A | 0.0001 | N/A |
| /data_20/surface_classification_flag | Computed from a mask built with MODIS and GlobCover data | N/A | byte | 127 | N/A | 1 | N/A |
| /data_20/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_20/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_20/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_20/tracker_range_counter | Tracker range counter with a resolution of 3.125/64 ns | count | int | 2147483647 | N/A | 1 | 2147483648 |
| /data_20/tracker_range_rate_counter | Tracker range rate counter with a resolution of 3.125/1024 ns | count | short | 32767 | N/A | 1 | N/A |
| samples | Set to be compliant with the CF-1.7 convention | count | byte | N/A | N/A | 1 | N/A |