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Description

This dataset contains concurrent airborne DopplerScatt radar retrievals of surface vector winds and ocean currents from the Sub-Mesoscale Ocean Dynamics Experiment (S-MODE) during a pilot campaign conducted approximately 300 km offshore of San Francisco over two weeks in October 2021. S-MODE aims to understand how ocean dynamics acting on short spatial scales influence the vertical exchange of physical and biological variables in the ocean. DopplerScatt is a Ka-band (35.75 GHz) scatterometer with a swath width of 24 km that records Doppler measurements of the relative velocity between the platform and the surface. It is mounted on a B200 aircraft which flies daily surveys of the field domain during deployments, and data is used to give larger scale context, and also to compare with in-situ measurements of velocities and divergence. Level 1 data includes geolocated physical measurements for a measurement footprint, which are the basis for the DopplerScatt L2 surface winds and currents estimates. Data are available in netCDF format and are ordered by measurement acquisition time and radar range, and are not on a geospatial grid.

Product Summary

Platforms
B-200
Instruments
SCATTEROMETERS
Spatial Extent

N: 38.1 S: 36.3 E: -122.5 W: -125.4

Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2021-05-03 to 2023-04-30
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2301076107-POCLOUD
Data State
COMPLETE
Number of Files/Granules
23717
Processing Level
1
Science Keywords
Doppler Velocity ,
Radar Backscatter

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

S-MODE. (2022). S-MODE DopplerScatt Level 1 Surface Doppler and Radar Backscatter Version 1 [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/SMODE-DSCT1 Date Accessed: 2026-05-30

Documents

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
pulse_pair_azimuth_angle_separation Estimated (signed) azimuth angle separation between each interferometric pulse-pair, in radians. rad double N/A N/A 1 N/A
pulse_pair_azimuth_angle_separation_standard_error Standard error of estimated azimuth angular separation between each interferometric pulse-pair, in radians. rad double N/A N/A 1 N/A
pulse_pair_burst_separation Number of burst intervals between each interferometric pulse-pair. N/A int -2147483648 N/A 1 N/A
pulse_pair_radial_sea_water_velocity_away_from_instrument Estimated radial component of sea surface velocity, in meters per second, for each computed pulse-pair interferogram. m s-1 double N/A N/A 1 N/A
pulse_pair_radial_sea_water_velocity_away_from_instrument_standard_deviation Sample standard deviation of multilooked radial velocity estimates, in meters per second, for each computed pulse-pair interferogram. Approximated from interferometric correlation coefficient using a simple model. m s-1 double N/A N/A 1 N/A
pulse_pair_temporal_separation Interferometric pulse-pair temporal separation, in seconds. s double N/A N/A 1 N/A
pulse_width Transmitted pulse duration, in seconds. s double N/A N/A 1 N/A
radial_sea_water_velocity_away_from_instrument Estimated radial component of sea surface velocity, in meters per second. If more than one pulse-pair interferogram was computed, this represents an inverse-variance-weighted average of the individual estimates. m s-1 double N/A N/A 1 N/A
radial_sea_water_velocity_away_from_instrument_standard_deviation Sample standard deviation of multilooked radial velocity estimates, in meters per second. Approximated from interferometric correlation coefficient using a simple model. m s-1 double N/A N/A 1 N/A
range_window_start_index Range bin index of the first valid return sample within the range sampling window. Preceding samples contain loop-back calibration data. N/A int -2147483648 N/A 1 N/A
sampling_rate Range sampling rate, in hertz. s-1 double N/A N/A 1 N/A
signal_region_far_edge_index Slant range index of the far edge of the estimated signal data region. N/A int -2147483648 N/A 1 N/A
signal_region_near_edge_index Slant range index of the near edge of the estimated signal data region. N/A int -2147483648 N/A 1 N/A
signal_to_noise_ratio Signal power to noise power ratio (SNR) (linear scale). N/A double N/A N/A 1 N/A
slant_range Slant range distance, in meters. m double N/A N/A 1 N/A
time Sensor acquisition time, in seconds since 1950-01-01T00:00:00Z seconds since 1950-01-01T00:00:00Z double N/A N/A 1 N/A
upward_platform_velocity Up component of platform velocity vector in East-North-Up (ENU) coordinates, in meters per second. m s-1 double N/A N/A 1 N/A
wavelength Radar central wavelength, in meters. m double N/A N/A 1 N/A
xfactor Conversion factor relating absolute received power, in watts, to normalized radar cross-section (sigma naught). N/A double N/A N/A 1 N/A
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