RSS SMAP Level 3 Sea Surface Salinity Standard Mapped Image Monthly V6.0 Validated Dataset

(SMAP_RSS_L3_SSS_SMI_MONTHLY_V6)
Version6.0
Processing Level3
Start/Stop Date2015-Apr-01 to Present
Short NameSMAP_RSS_L3_SSS_SMI_MONTHLY_V6
DescriptionThe RSS SMAP Level 3 Sea Surface Salinity Standard Mapped Image Monthly V6.0 Validated Dataset produced by the Remote Sensing Systems (RSS) and sponsored by the NASA Ocean Salinity Science Team, is a validated product that provides orbital/swath data on sea surface salinity (SSS) derived from the NASA's Soil Moisture Active Passive (SMAP) mission. The SMAP satellite was launched on 31 January 2015 with a near-polar orbit at an inclination of 98 degrees and an altitude of 685 km. It has an ascending node time of 6 pm and is sun-synchronous. With its 1000km swath, SMAP achieves global coverage in approximately 3 days, but has an exact orbit repeat cycle of 8 days. Malfunction of the SMAP scatterometer on 7 July, 2015, has necessitated the use of collocated wind speed, primarily from WindSat, for the surface roughness correction required for the surface salinity retrieval.

The major changes in Version 6.0 from Version 5.0 are: (1) Removal of biases during the first few months of the SMAP mission that are related to the operation of the SMAP radar during that time. (2) Mitigation of biases that depend on the SMAP look angle. (3) Mitigation of salty biases at high Northern latitudes. (4) Revised sun-glint flag. The RSS SMAP L3 monthly product includes data for a range of parameters: derived sea surface salinity (SSS) with SSS-uncertainty, rain filtered SMAP sea surface salinity, collocated wind speed, data and ancillary reference surface salinity data from HYCOM. Each data file is available in netCDF-4 file format and is averaged over one-month time intervals with about 7-day latency (after the end of the averaging period). Data begins on April 1,2015 and is ongoing. Observations are global in extent with an approximate spatial resolution of 40KM. Note that while a SSS 40KM variable is also included in the product for most open ocean applications, The standard product of the SMAP Version 6.0 release is the smoothed salinity product with a spatial resolution of approximately 70 km.
DOI10.5067/SMP60-3SMCS
MeasurementOCEANS > SALINITY/DENSITY > SALINITY
Platform/Sensor
SMAP
Platform
Name: NASA Soil Moisture Active Passive (SMAP) (SMAP)
Orbit Period: 98.5 minutes
Inclination Angle: 98.0 degrees
/
SMAP L-BAND RADIOMETER
SENSOR
Name: SMAP L-Band Radiometer (SMAP L-BAND RADIOMETER)
Swath Width: 1000.0 kilometers
Description: Spacecraft angular distance from orbital plane relative to the Equator.

ProjectSoil Moisture Active Passive (SMAP)
Data ProviderPublisher: Remote Sensing Systems (RSS)
Creator: Remote Sensing Systems (RSS)
Release Place: Remote Sensing Systems, 444 Tenth Street, Suite 200, Santa Rosa, CA 95401, USA
Release Date: 2024-Mar-26
Resource: http://podaac.jpl.nasa.gov/smap

FormatnetCDF-4
Keyword(s)RssSmapSSSv5, V5, L3, Level 3, Monthly, SMAP, SMAP-SSS, Soil Moisture Active, Passive, salinity, polar, sun-synchronous, sss, sea surface, salinity, psu, NASA, project, mission, RSS, REMSS, Remote Sensing Systems
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
Resolution
Spatial Resolution: 0.25 Decimal Degrees x 0.25 Decimal Degrees
Temporal Resolution: Monthly - < Annual
 
Coverage
Region: GLOBAL
North Bounding Coordinate: 90 degrees
South Bounding Coordinate: -90 degrees
West Bounding Coordinate: -180 degrees
East Bounding Coordinate: 180 degrees
Time Span: 2015-Apr-01 to Present
 
Projection
Projection Type: Gridded
Ellipsoid: WGS 84
 
NameLong NameUnit
flandaverage land fraction within 3dB contour1
gice_estestimated sea ice fraction weighted by antenna gain1
glandaverage land fraction weighted by antenna gain1
latcenter latitude of grid celldegrees_north
loncenter longitude of grid celldegrees_east
nobsNumber of observations for L3 average of SSS smoothed to approx 70km resolution1
nobs_40kmNumber of observations for L3 average of SSS at 40km resolution1
nobs_RFNumber of observations for L3 average of rain filtered SSS smoothed to approx 70km resolution1
sss_refReference sea surface salinity from HYCOM1e-3
sss_smapSMAP sea surface salinity smoothed to approx 70km resolution1e-3
sss_smap_40kmSMAP sea surface salinity at original 40km resolution1e-3
sss_smap_40km_unctotal formal uncertainty estimate of SMAP sea surface salinity at original 40km resolution1e-3
sss_smap_40km_unc_compformal uncertainty components of SMAP sea surface salinity at original 40km resolution1e-3
sss_smap_RFRain filtered SMAP sea surface salinity smoothed to approx 70km resolution1e-3
sss_smap_RF_unctotal formal uncertainty estimate of rain filtered SMAP sea surface salinity smoothed to approx 70km resolution1e-3
sss_smap_unctotal formal uncertainty estimate of SMAP sea surface salinity smoothed to approx 70km resolution1e-3
sss_smap_unc_compformal uncertainty components of SMAP sea surface salinity smoothed to approx 70km resolution1e-3
surtepAncillary sea surface temperature (from CMC)Kelvin
timereference time of analyzed variable field corresponding to center of the product time intervalseconds since 2000-01-01T00:00:00Z
winspdAncillary sea surface wind speed from CCMP NRT that is used in surface roughness correctionm s-1
ANOMALIES
USER'S GUIDE
GENERAL DOCUMENTATION
DATA CITATION POLICY
DATA RECIPE
Citation is critically important for dataset documentation and discovery. Please cite the data as follows, and cite the reference papers when it is appropriate.
Citation Remote Sensing Systems (RSS). 2024. SMAP Sea Surface Salinity Products. Ver. 6.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/SMP60-3SMCS

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For more information see Data Citations and Acknowledgments.
Journal Reference Meissner, T. and F. J. Wentz, 2018: Remote Sensing Sytems SMAP Ocean Surface Salinities, Version 4.0 validated release. Remote Sensing Systems, Santa Rosa, CA, USA.

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