IPRC/SOEST Aquarius V5.0 Optimally Interpolated Sea Surface Salinity 7-Day global Dataset

IPRC/SOEST Aquarius V5.0 Optimally Interpolated Sea Surface Salinity 7-Day global Dataset
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DescriptionThe IPRC/SOEST Aquarius OI-SSS v5 product is a level 4, near-global, 0.5 degree spatial resolution, 7-day, optimally interpolated salinity dataset based on version 5.0 of the AQUARIUS/SAC-D level 2 mission data. This is a PI led dataset produced at the International Pacific Research Center (IPRC) at the University of Hawaii (Manoa) School of Ocean and Earth Science and Technology. The optimal interpolation (OI) mapping procedure used to create this product corrects for systematic spatial biases in Aquarius SSS data with respect to near-surface in situ salinity observations and takes into account available statistical information about the signal and noise, specific to the Aquarius instrument. Bias fields are constructed by differencing in situ from Aquarius derived SSS fields obtained separately using ascending and descending satellite observations for each of the three Aquarius beams, and by removal of small-scale noise and low-pass filtering along-track using a two-dimensional Hanning window procedures prior to application of the OI algorithm. Additional enhancements for this new version of the product include: 1) The V5.0 (end-of mission) version of Aquarius Level-2 (swath) SSS data are used as input data for the OI SSS analysis. 2) The source of the first guess fields has changed from the APDRC Argo-derived SSS product to the average of four different in-situ based SSS products. 3) The bias correction algorithm has changed to adjust SSS retrievals for large-scale systematic biases on a repeat-track basis. 4) New, less restrictive thresholds are implemented to filter observations for land and ice contamination, thus improving coverage in the coastal areas and semi-enclosed seas. 5) Level-2 RFI masks for descending and ascending satellite passes are used to discard observations in specific geographic zones where excessive ascending-descending differences are observed due to contamination from undetected RFI. 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. The Aquarius polar orbit is sun synchronous at 657 km with a 6 pm, ascending node, and has a 7-Day repeat cycle.
Dataset TypeOPEN
MeasurementOceans > Salinity/Density > Salinity > None
Processing Level4
CoverageRegion: Global
Northernmost Latitude: 90 degrees
Southernmost Latitude: -90 degrees
Westernmost Longitude: -180 degrees
Easternmost Longitude: 180 degrees
Time Span: 2011-Aug-27 to 2015-Jun-07
ResolutionSpatial Resolution: 0.5 degrees (Latitude) x 0.5 degrees (Longitude)
Temporal Resolution: 7 Day
ProjectionType: Gridded
Ellipsoid: WGS 84
Latency720 hours
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: Oleg Melnichenko
Release Place: IPRC/SOEST University of Hawaii, Manoa
Release Date: 2018-Aug-31
Resource: http://apdrc.soest.hawaii.edu/datadoc/oisss.php
Keyword(s)v5, Aquarius, salinity, SSS, OI, oisss, optimally interpolated, IPRC, SOEST, polar, sun-synchronous, sss, psu, CONAE, argentina, JPL
Persistent IDPODAAC-AQR50-4U7CS
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
User's Guide
IPRC/SOEST Aquarius L4 OI-SSS ATBD Addendum for V5https://podaac-tools.jpl.nasa.gov/drive/files/allData/aquarius/docs/IPRC_OISSS/Melnichenko_AqSssOI_v5_Addendum_TechnicalNotes.pdf
IPRC/SOEST Aquarius L4 OI-SSS Algorithm Guide
IPRC/SOEST Aquarius L4 OI-SSS ATBDhttps://podaac-tools.jpl.nasa.gov/drive/files/allData/aquarius/docs/IPRC_OISSS/Melinchenko_AqSssOI_Technical_Notes.pdf
IPRC/SOEST Aquarius L4 OI-SSS Algorithm Guide
Project Materials
IPRC/SOEST Aquarius L4 OI-SSS Documentation Packagehttps://podaac-tools.jpl.nasa.gov/drive/files/allData/aquarius/docs/IPRC_OISSS/
ATBD, Publications
Additional Sites
PO.DAAC Aquarius/SAC-D Mission pagehttp://podaac.jpl.nasa.gov/aquarius
Mission and Instrument Overview
Aquarius/SAC-D Mission Websitehttp://aquarius.nasa.gov/
NASA Aquarius/SAC-D mission website
Citation Oleg Melnichenko. 2018. IPRC/SOEST Aquarius V5.0 Optimally Interpolated Sea Surface Salinity 7-Day global Dataset. Ver. 5.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/AQR50-4U7CS.

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For more information see Data Citations and Acknowledgments.

Journal Reference Melnichenko, O., P. Hacker., N. Maximenko, G. Lagerloef, and J. Potemra (2016), Optimal interpolation of Aquarius sea surface salinity, J. Geophys. Res. Oceans, 121, 602-616, doi:10.1002/2015JC011343