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Description

This is a level 4 product on a 0.25-degree spatial and 4-day temporal grid. The product is derived from the level 2 swath data of three satellite missions: the Aquarius/SAC-D, Soil Moisture Active Passive (SMAP) and Soil Moisture and Ocean Salinity (SMOS) using Optimal Interpolation (OI) with a 7-day decorrelation time scale. The product offers a continuous record from August 28, 2011 to present by concatenating the measurements from Aquarius (September 2011 - June 2015) and SMAP (April 2015 present). ESAs SMOS data was used to fill the gap in SMAP data between June and July 2019, when the SMAP satellite was in a safe mode. The two-month overlap (April - June 2015) between Aquarius and SMAP was used to ensure consistency and continuity in data record. The product covers the global ocean, including the Arctic and Antarctic in the areas free of sea ice, but does not cover internal seas such as Mediterranean and Baltic Sea. In-situ salinity from Argo floats and moored buoys are used to derive a large-scale bias correction and to ensure consistency and accuracy of the OISSS dataset. This dataset is produced by the Earth and Space Research (ESR), Seattle, WA and the International Pacific Research Center (IPRC) of the University of Hawaii at Manoa in collaboration with the Remote Sensing Systems (RSS), Santa Rosa, California. More details can be found in the users guide.

Product Summary

Platforms
SMAP ,
SAC-D ,
SMOS
Instruments
SMAP L-BAND RADIOMETER ,
AQUARIUS_SCATTEROMETER
Spatial Extent

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

Spatial Resolution
0.25 Decimal Degrees x 0.25 Decimal Degrees
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2011-08-24
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC) ,
International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii (UHI/SOEST/IPRC)
Concept ID
C2589160971-POCLOUD
Data State
COMPLETE
Number of Files/Granules
1220
Processing Level
4
Published
Updated
Science Keywords
Salinity

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

IPRC/SOEST, U. of H. (2023). Multi-Mission Optimally Interpolated Sea Surface Salinity 7-Day Global Dataset V2 [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/SMP20-4U7CS Date Accessed: 2025-12-14

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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
latitude latitude degrees_north float N/A -90 to 90 1
longitude longitude degrees_east float N/A -180 to 180 1
sss sea surface salinity 1e-3 float -9999 0 to 45 1
sss_empirical_uncertainty estimated empirical uncertainty of multi-mission OISSS 1e-3 float -9999 0 to 45 1
sss_formal_uncertainty estimated formal uncertainty of multi-mission OISSS 1e-3 float -9999 0 to 45 1
time center day of a time period over which satellite Level 2 SSS data have been collected for OISSS analysis Days since 2010-12-31T00:00:00Z float N/A N/A 1
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