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Description

The SWOT Level 2 KaRIn Low Rate Sea Surface Height Data Product from the Surface Water Ocean Topography (SWOT) mission provides global sea surface height and significant wave height observations derived from low rate (LR) measurements from the Ka-band Radar Interferometer (KaRIn). SWOT launched on December 16, 2022 from Vandenberg Air Force Base in California into a 1-day repeat orbit for the "calibration" or "fast-sampling" phase of the mission, which completed in early July 2023. After the calibration phase, SWOT entered a 21-day repeat orbit in August 2023 to start the "science" phase of the mission, which is expected to continue through 2025. <br>
The L2 sea surface height data product is distributed in one netCDF-4 file per pass (half-orbit) covering the full KaRIn swath width, which spans 10-60km on each side of the nadir track. Sea surface height, sea surface height anomaly, wind speed, significant waveheight, and related parameters are provided on a geographically fixed, swath-aligned 2x2 km2 grid (Basic, Expert, Windwave). The sea surface height data are also provided on a finer 250x250 m2 "native" grid with minimal smoothing applied (Unsmoothed).<br>
Please note that this collection contains SWOT Version C science data products. <br>
This dataset is the parent collection to the following sub-collections: <br>
https://podaac.jpl.nasa.gov/dataset/SWOT_L2_LR_SSH_Basic_2.0 <br>
https://podaac.jpl.nasa.gov/dataset/SWOT_L2_LR_SSH_WindWave_2.0 <br>
https://podaac.jpl.nasa.gov/dataset/SWOT_L2_LR_SSH_Expert_2.0 <br>
https://podaac.jpl.nasa.gov/dataset/SWOT_L2_LR_SSH_Unsmoothed_2.0 <br>

Product Summary

Platforms
SWOT
Instruments
KaRIn ,
Jason-class Altimeter ,
AMR ,
DORIS ,
GPSP ,
LRA
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Spatial Resolution
2 Kilometers x 2 Kilometers
250 Meters x 250 Meters
Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2022-12-16
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2799438306-POCLOUD
Data State
SUPERSEDED
Number of Files/Granules
90959
Processing Level
2
Published
Updated
Science Keywords
Sea Surface Height ,
Significant Wave Height

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

SWOT. (2024). SWOT Level 2 KaRIn Low Rate Sea Surface Height Data Product [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/SWOT-SSH-2.0 Date Accessed: 2026-05-14

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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 Description Units Data Type Fill Value Valid Range Scale Factor Offset
ssha_karin Sea surface height anomaly from the KaRIn measurement = ssh_karin - mean_sea_surface_cnescls - solid_earth_tide - ocean_tide_fes – internal_tide_hret - pole_tide - dac. m int 2147483647 -1000000 to 1000000 0.0001 N/A
ssha_karin_2 Sea surface height anomaly from the KaRIn measurement = ssh_karin_2 - mean_sea_surface_cnescls - solid_earth_tide - ocean_tide_fes – internal_tide_hret - pole_tide - dac. m int 2147483647 -1000000 to 1000000 0.0001 N/A
ssha_karin_2_qual Quality flag for the SSHA from KaRIn in the ssha_karin_2 variable N/A uint 4294967295 0 to 3876569055 1 N/A
ssha_karin_qual Quality flag for the SSHA from KaRIn in the ssha_karin variable. N/A uint 4294967295 0 to 4279222239 1 N/A
ssh_karin Fully corrected sea surface height measured by KaRIn. The height is relative to the reference ellipsoid defined in the global attributes. This value is computed using radiometer measurements for wet troposphere effects on the KaRIn measurement (e.g., rad_wet_tropo_cor and sea_state_bias_cor). m int 2147483647 -15000000 to 150000000 0.0001 N/A
ssh_karin_2 Fully corrected sea surface height measured by KaRIn. The height is relative to the reference ellipsoid defined in the global attributes. This value is computed using model-based estimates for wet troposphere effects on the KaRIn measurement (e.g., model_wet_tropo_cor and sea_state_bias_cor_2). m int 2147483647 -15000000 to 150000000 0.0001 N/A
ssh_karin_2_qual Quality flag for sea surface height from KaRIn in ssh_karin_2 variable. N/A uint 4294967295 0 to 3809460191 1 N/A
ssh_karin_qual Quality flag for sea surface height from KaRIn in ssh_karin variable. N/A uint 4294967295 0 to 4212113375 1 N/A
ssh_karin_uncert 1-sigma uncertainty on the sea surface height from the KaRIn measurement. m ushort 65535 0 to 60000 0.0001 N/A
swh_karin Significant wave height from KaRIn volumetric correlation. m ushort 65535 0 to 15000 0.001 N/A
swh_karin_qual Quality flag for significant wave height from KaRIn in swh_karin_qual variable. N/A uint 4294967295 0 to 3792059800 1 N/A
swh_karin_uncert 1-sigma uncertainty on significant wave height from KaRIn. m ushort 65535 0 to 25000 0.001 N/A
swh_model Significant wave height from model. m ushort 65535 0 to 15000 0.001 N/A
swh_nadir_altimeter Significant wave height from nadir altimeter. m ushort 65535 0 to 15000 0.001 N/A
swh_ssb_cor_source Bit flag that indicates the source of significant wave height information that was used to compute the sea state bias correction in sea_state_bias_cor. N/A ubyte 255 0 to 7 1 N/A
swh_ssb_cor_source_2 Bit flag that indicates the source of significant wave height information that was used to compute the sea state bias correction in sea_state_bias_cor_2. N/A ubyte 255 0 to 7 1 N/A
swh_wind_speed_karin_source Bit flag that indicates the source of significant wave height information that was used to compute the wind speed estimate from KaRIn data in wind_speed_karin. N/A ubyte 255 0 to 7 1 N/A
swh_wind_speed_karin_source_2 Bit flag that indicates the source of significant wave height information that was used to compute the wind speed estimate from KaRIn data in wind_speed_karin_2. N/A ubyte 255 0 to 7 1 N/A
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
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 9.9692099683869E+36 N/A 1 N/A
velocity_heading Angle with respect to true north of the horizontal component of the spacecraft Earth-relative velocity vector. A value of 90 deg indicates that the spacecraft velocity vector pointed due east. Values between 0 and 90 deg indicate that the velocity vector has a northward component, and values between 90 and 180 deg indicate that the velocity vector has a southward component. degrees int 2147483647 0 to 359999999 1.0E-6 N/A
volumetric_correlation Volumetric correlation. 1 ushort 65535 0 to 20000 0.0001 N/A
volumetric_correlation_uncert 1-sigma uncertainty computed analytically using observed correlation and effective number of looks. Two-sided error bars (volumetric_correlation-volumetric_correlation_uncert, volumetric_correlation+volumetric_correlation_uncert) include 68% of probability distribution. 1 ushort 65535 0 to 10000 0.01 N/A
wind_speed_karin Wind speed from KaRIn computed from sig0_karin. m/s ushort 65535 0 to 65000 0.001 N/A
wind_speed_karin_2 Wind speed from KaRIn computed from sig0_karin_2. m/s ushort 65535 0 to 65000 0.001 N/A
wind_speed_karin_2_qual Quality flag for wind speed from KaRIn in wind_speed_karin_2 variable. N/A uint 4294967295 0 to 3792125336 1 N/A
wind_speed_karin_qual Quality flag for wind speed from KaRIn in wind_speed_karin variable. N/A uint 4294967295 0 to 4060560792 1 N/A
wind_speed_model_u Eastward component of the atmospheric model wind vector at 10 meters. m/s short 32767 -30000 to 30000 0.001 N/A
wind_speed_model_v Northward component of the atmospheric model wind vector at 10 meters. m/s short 32767 -30000 to 30000 0.001 N/A
wind_speed_rad Wind speed from radiometer measurements. m/s ushort 65535 0 to 65000 0.001 N/A
wind_speed_ssb_cor_source Bit flag that indicates the source of wind speed information that was used to compute the sea state bias correction in sea_state_bias_cor. N/A ubyte 255 0 to 7 1 N/A
wind_speed_ssb_cor_source_2 Bit flag that indicates the source of wind speed information that was used to compute the sea state bias correction in sea_state_bias_cor_2. N/A ubyte 255 0 to 7 1 N/A
x_factor Radiometric calibration X factor as a linear power ratio. 1 float 9.96921E+36 0 to 1.0E+20 1 N/A
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