Aquarius CAP Level 2 Sea Surface Salinity, Wind Speed & Direction Data V5.0

Aquarius CAP Level 2 Sea Surface Salinity, Wind Speed & Direction Data V5.0
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DescriptionThe 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.
Dataset TypeOPEN
MeasurementOceans > Salinity/Density > Salinity
Oceans > Ocean Winds > Surface Winds > Surface Wind Speed
Processing Level2
CoverageRegion: Global
Northernmost Latitude: 90 degrees
Southernmost Latitude: -90 degrees
Westernmost Longitude: -180 degrees
Easternmost Longitude: 180 degrees
Time Span: 2011-Aug-26 to 2015-Jun-05
ResolutionSpatial Resolution: 96 km (Along) x 390 km (Across)
ProjectionType: Swath
Latency720 hours
Swath Width3 m
Sample Frequency-
Temporal Repeat (Nominal)7 Day
Temporal Repeat (Min)7 Day
Temporal Repeat (Max)7 Day
Name: Aquarius SAC-D (Aquarius_SAC-D)
Orbit Period: 98 minutes
Inclination Angle: 98 degrees
Ascending Node: 1970-Jan-01 00:00:00
Name: Aquarius Radiometer (AQUARIUS_RADIOMETER)
Swath Width: 390 km
Description: Launched in 2011 the 3 Aquarius radiometers meet very exacting requirements for low noise and calibration stability. This makes them about an order of magnitude more accurate than any radiometer ever used before for remote sensing of the earth. Aquarius measures in the microwave range at 1.413 GHz (+/- 25MHz).

Name: Aquarius SAC-D (Aquarius_SAC-D)
Orbit Period: 98 minutes
Inclination Angle: 98 degrees
Ascending Node: 1970-Jan-01 00:00:00
Name: Aquarius Scatterometer (AQUARIUS_SCATTEROMETER)
Swath Width: 390 km
Description: The Aquarius scatterometer is a total-power L-band (1.26 GHz)radar system for estimating ocean surface roughness. Itsmeasurements will enable the removal of wind effects from theAquarius radiometer ocean-surface brightness temperaturemeasurements being used to retrieve ocean salinity. TheAquarius scatterometer is a relatively simple, low-spatialresolution power-detecting radar, without ranging capability.But to meet its science requirement, it must be very stable, withrepeatability on the order of 0.1 dB over several days, andcalibrated accuracy to this level over several months. Datafrom this instrument over land as well as ocean areas will beavailable for a variety of geophysical applications.

Data ProviderCreator: Simon Yueh
Release Place: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA91109, USA
Release Date: 2018-Oct-01
Keyword(s)Aquarius, CAP, CAPv5, salinity, wind speed, wind direction, polar, sun-synchronous, sss, psu, CONAE, argentina, JPL
Questions related to this dataset? Contact
User's Guide
Aquarius-CAP Users Guide and ATBD
Aquarius CAP V5.0 Algorithm and Data Users Guide
Project Materials
Aquarius-CAP V5.0 Documentation Package
ATBD, Validation and Uncertainty Analyses, Publications, etc
Additional Sites
PO.DAAC Aquarius/SAC-D Mission page
Mission and Instrument Overview
Aquarius/SAC-D Mission Website
NASA Aquarius/SAC-D mission website
Citation Simon Yueh. 2018. Aquarius CAP Level 2 Sea Surface Salinity, Wind Speed & Direction Data V5.0. Ver. 5.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at

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For more information see Data Citations and Acknowledgments.

Journal Reference Yueh,S.H., W.Tang,A.K.Hayashi,G.S.E.Lagerloef (2014). L-Band Passive and Active Microwave Geophysical Model Functions of Ocean Surface Winds and Applications to Aquarius Retrieval. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING,51(9), 4619-4632