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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: 2025-12-14

Documents

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
antenna_boresight_unit_vector_east_component East component of antenna boresight look unit vector in East-North-Up (ENU) coordinates. N/A double N/A N/A 1
antenna_boresight_unit_vector_north_component North component of antenna boresight look unit vector in East-North-Up (ENU) coordinates. N/A double N/A N/A 1
antenna_boresight_unit_vector_up_component Up component of antenna boresight look unit vector in East-North-Up (ENU) coordinates. N/A double N/A N/A 1
antenna_encoder_angle Angular position of the rotating antenna, in radians, recorded by the rotary encoder. Measured counter-clockwise positive from the right-looking broadside direction. rad double N/A 0 to 6.2831853071796 1
azimuth_angle_offset Offset applied to estimated azimuth angle, in radians. rad double N/A -3.1415926535898 to 3.1415926535898 1
bandwidth Range frequency bandwidth, in hertz. s-1 double N/A N/A 1
burst_repetition_interval Burst repetition interval (BRI), in seconds. s double N/A N/A 1
calpulse_mean_power Nominal (estimated) mean power in a 6us calibration pulse (linear scale). N/A double N/A N/A 1
calpulse_pulsecompress_peak_delay Temporal position of the pulse-compressed calibration pulse peak sample, in seconds relative to the start of the range sampling window. s double N/A N/A 1
calpulse_pulsecompress_peak_phase Phase, in radians, of the pulse-compressed calibration pulse peak sample. rad double N/A -3.1415926535898 to 3.1415926535898 1
calpulse_pulsecompress_peak_power Power (linear scale) of the pulse-compressed calibration pulse peak sample. N/A double N/A N/A 1
correlation_coefficient Interferometric correlation coefficient of each computed pulse-pair interferogram. N/A double N/A 0 to 1 1
derivative_of_platform_radial_velocity_wrt_azimuth_angle Rate of change of the radial component of platform velocity with respect to azimuth angle, in meters per second per radian. m s-1 rad-1 double N/A N/A 1
distance_from_coast Minimum distance from coast, in kilometers. A negative value indicates that the observation point was inland. km double N/A N/A 1
dn_to_milliwatts_conversion_factor Scale factor applied to raw I/Q samples to convert from digital numbers to milliwatts. N/A double N/A N/A 1
eastward_platform_velocity East component of platform velocity vector in East-North-Up (ENU) coordinates, in meters per second. m s-1 double N/A N/A 1
far_range_noise_power Average multilooked power (linear scale) of noise samples on the far side of the swath, in watts. W double N/A N/A 1
height Sea surface height above reference ellipsoid, in meters. m double N/A N/A 1
interpulse_period Inter-pulse period (IPP), in seconds. Interval between successive pulses within a burst. s double N/A N/A 1
latitude Geodetic latitude of the observation point, in degrees. degree_north double N/A -90 to 90 1
line_of_sight_unit_vector_east_component East component of platform-to-target line-of-sight unit vector in East-North-Up (ENU) coordinates. N/A double N/A N/A 1
line_of_sight_unit_vector_north_component North component of platform-to-target line-of-sight unit vector in East-North-Up (ENU) coordinates. N/A double N/A N/A 1
line_of_sight_unit_vector_up_component Up component of platform-to-target line-of-sight unit vector in East-North-Up (ENU) coordinates. N/A double N/A N/A 1
longitude Geodetic longitude of the observation point, in degrees. degree_east double N/A -180 to 180 1
low_correlation_mask Indicates pixels with interferometric correlation coefficient below a specified threshold. (0 = good correlation, 2 = low correlation) N/A int -2147483648 N/A 1
low_correlation_threshold Correlation coefficient threshold for detecting low correlation data. N/A double N/A 0 to 1 1
mean_noise_power Average power of noise samples, in watts (linear scale). W double N/A N/A 1
milliwatts_adc_to_watts_conversion_factor Scale factor applied to multilooked power data to convert from milliwatts to watts and remove system gain. N/A double N/A N/A 1
near_range_noise_power Average multilooked power (linear scale) of noise samples on the near side of the swath, in watts. W double N/A N/A 1
noise_estimation_buffer_samples Number of buffer samples excluded from the noise region (on either side of the signal data region) when classifying return samples as either signal or noise for SNR estimation. N/A int -2147483648 N/A 1
normalized_radar_cross_section Normalized radar cross-section (sigma naught). N/A double N/A N/A 1
normalized_radar_cross_section_variance Estimated variance of normalized radar cross-section (sigma naught). N/A double N/A N/A 1
normalized_standard_deviation_of_return_energy Normalized standard deviation of backscatter energy (Kp coefficient). N/A double N/A N/A 1
northward_platform_velocity North component of platform velocity vector in East-North-Up (ENU) coordinates, in meters per second. m s-1 double N/A N/A 1
number_of_looks Azimuth multilook window size, in pixels. N/A int -2147483648 N/A 1
off_boresight_angle Angle between the boresight look vector and the platform-to-target line-of-sight vector, in radians. rad double N/A 0 to 3.1415926535898 1
platform_altitude Platform altitude above reference ellipsoid, in meters. m double N/A N/A 1
platform_azimuth_angle Platform-to-target azimuth angle, in radians, measured clockwise from geographic north. rad double N/A -3.1415926535898 to 3.1415926535898 1
platform_heading_angle Platform heading angle, in radians, measured clockwise positive from geographic north. rad double N/A -3.1415926535898 to 3.1415926535898 1
platform_latitude Platform geodetic latitude, in degrees. degree_north double N/A -90 to 90 1
platform_longitude Platform geodetic longitude, in degrees. degree_east double N/A -180 to 180 1
platform_look_angle Platform-to-target look angle, in radians. This is the angle between the line-of-sight vector and the platform nadir vector (normal to the ellipsoid surface). rad double N/A 0 to 3.1415926535898 1
platform_pitch_angle Platform pitch angle, in radians. rad double N/A -3.1415926535898 to 3.1415926535898 1
platform_radial_velocity Radial component of platform velocity, in meters per second. m s-1 double N/A N/A 1
platform_roll_angle Platform roll angle, in radians. rad double N/A -3.1415926535898 to 3.1415926535898 1
platform_yaw_angle Platform yaw angle, in radians. rad double N/A -3.1415926535898 to 3.1415926535898 1
power Multilooked power (linear scale), in watts. W double N/A N/A 1
processing_beamwidth Nominal processing beamwidth, in degrees. Used to determine the range and azimuth extents of the swath. This is not necessarily the same as the antenna -3dB beamwidth. degree double N/A 0 to 360 1
pulse_compression_gain White noise gain (WNG) due to pulse compression (linear scale). Incorporates losses due to processing window effects. N/A double N/A N/A 1
pulse_compression_normalization_factor Scale factor applied to pulse-compressed data to normalize to unit white noise gain (WNG). N/A double N/A N/A 1
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