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Description

The version 5.0 Aquarius CAP Level 2 product contains the fourth release of the AQUARIUS/SAC-D orbital/swath data based on the Combined Active Passive (CAP) algorithm. CAP is a P.I. produced dataset developed and provided by JPL. This Level 2 dataset contains sea surface salinity (SSS), wind speed and wind direction data derived from 3 different radiometers and the onboard scatterometer. The CAP algorithm simultaneously retrieves the salinity, wind speed and direction by minimizing the sum of squared differences between model and observations. The main improvements in CAP V5.0 relative to the previous version include: updates to the Geophysical Model Functions to 4th order harmonics with the inclusion of sea surface temperature (SST) and stability at air-sea interface effects; use of the Canadian Meteorological Center (CMC) SST product as the new source ancillary sea surface temperature data in place of NOAA OI SST. Each L2 data file covers one 98 minute orbit. The Aquarius instrument is onboard the AQUARIUS/SAC-D satellite, a collaborative effort between NASA and the Argentinian Space Agency Comision Nacional de Actividades Espaciales (CONAE). The instrument consists of three radiometers in push broom alignment at incidence angles of 29, 38, and 46 degrees incidence angles relative to the shadow side of the orbit. Footprints for the beams are: 76 km (along-track) x 94 km (cross-track), 84 km x 120 km and 96km x 156 km, yielding a total cross-track swath of 370 km. The radiometers measure brightness temperature at 1.413 GHz in their respective horizontal and vertical polarizations (TH and TV). A scatterometer operating at 1.26 GHz measures ocean backscatter in each footprint that is used for surface roughness corrections in the estimation of salinity. The scatterometer has an approximate 390km swath.

Product Summary

Platforms
SAC-D
Instruments
AQUARIUS_RADIOMETER
Spatial Extent

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

Location
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2011-08-26 to 2015-06-05
Data Partner
AQUARIUS, Jet Propulsion Laboratory, NASA (NASA/JPL/AQUARIUS) ,
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2205121315-POCLOUD
Data State
COMPLETE
Number of Files/Granules
20269
Processing Level
2
Published
Updated
Science Keywords
Salinity ,
Surface Winds

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

JPL. (2018). Aquarius CAP Level 2 Sea Surface Salinity, Wind Speed & Direction Data V5.0 [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/AQR50-2TOCS Date Accessed: 2026-04-13

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
anc_SSS Sea surface salinity climatology PSU float N/A N/A 1 N/A
anc_surface_temp Surface temperature Kelvin float N/A N/A 1 N/A
anc_swh Ancillary significant wave height Meters float N/A N/A 1 N/A
anc_wind_dir Ancillary wind direction 10m above surface Degrees float N/A N/A 1 N/A
anc_wind_speed Ancillary wind speed 10m above surface Meters/second float N/A N/A 1 N/A
beam_clat Beam center latitude Degrees float N/A N/A 1 N/A
beam_clon Beam center longitude Degrees float N/A N/A 1 N/A
cap_far_rot CAP Faraday rotation angle Degrees float N/A N/A 1 N/A
cap_flag CAP quality flag N/A ubyte N/A N/A 1 N/A
ice_frac Fraction of ice contamination (radiometer) N/A float N/A N/A 1 N/A
land_frac Fraction of land contamination (radiometer) N/A float N/A N/A 1 N/A
scat_ice_frac Fraction of ice contamination (scatterometer) N/A float N/A N/A 1 N/A
scat_land_frac Fraction of land contamination (scatterometer) N/A float N/A N/A 1 N/A
scat_swh_wind_speed Scatterometer-only wind speed with SWH GMF Meters/second float N/A N/A 1 N/A
scat_wind_speed Scatterometer-only wind speed Meters/second float N/A N/A 1 N/A
sec Block time, seconds of day Seconds double N/A N/A 1 N/A
SSS Sea surface salinity PSU float N/A N/A 1 N/A
SSS_cap CAP Sea surface salinity PSU float N/A N/A 1 N/A
SSS_cap_h SSS_cap_h N/A float N/A N/A 1 N/A
SSS_cap_rc CAP Sea surface salinity with rain correction PSU float N/A N/A 1 N/A
SSS_cap_v SSS_cap_v N/A float N/A N/A 1 N/A
wind_dir_cap CAP wind direction Degrees float N/A N/A 1 N/A
wind_dir_cap_rc CAP_RC wind direction Degrees float N/A N/A 1 N/A
wind_speed_cap CAP wind speed Meters/second float N/A N/A 1 N/A
wind_speed_cap_rc CAP_RC wind speed Meters/second float N/A N/A 1 N/A
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