JPL SMAP Level 2B Near Real-time CAP Sea Surface Salinity V5.0 Validated Dataset

(SMAP_JPL_L2B_NRT_SSS_CAP_V5)
3 Publications Cited this Dataset
Citation metrics available for years (2014-2022)
Version5.0
Processing Level2
Start/Stop Date2015-Apr-01 to Present
Short NameSMAP_JPL_L2B_NRT_SSS_CAP_V5
DescriptionThis is the PI-produced JPL SMAP-SSS V5.0, level 2B NRT CAP, validated sea surface salinity (SSS) and extreme winds orbital/swath product from the NASA Soil Moisture Active Passive (SMAP) observatory available in near real-time with a latency of about 6 hours. It is based on the Combined Active-Passive (CAP) retrieval algorithm developed at JPL originally in the context of Aquarius/SAC-D and now extended to SMAP. JPL SMAP V5.0 SSS is based on the newly released SMAP V5 Level-1 Brightness Temperatures (TB). An enhanced calibration methodology has been applied to the brightness temperatures, which improves absolute radiometric calibration and reduces the biases between ascending and descending passes. The improved SMAP TB Level 1 TB will enhance the use of SMAP Level-1 data for other applications, such as sea surface salinity and winds. The JPL SMAP-SSS L2B CAP NRT product includes data for a range of parameters: derived SMAP sea surface salinity, SSS uncertainty and wind speed/direction data for extreme winds, brightness temperatures for each radiometer polarization, ancillary reference surface salinity, ice concentration, wind and wave height data, quality flags, and navigation data. Each data file covers one 98-minute orbit (15 files per day). Data begins on April 1,2015 and is ongoing, with a 6 hour latency in processing and availability. Observations are global in extent and provided at 25km swath grid with an approximate spatial resolution of 60 km.The SMAP satellite is in 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. On board Instruments include a highly sensitive L-band radiometer operating at 1.41GHz and an L-band 1.26GHz radar sensor providing complementary active and passive sensing capabilities. Malfunction of the SMAP scatterometer on 7 July, 2015, has necessitated the use of collocated wind speed for the surface roughness correction required for the surface salinity retrieval.
DOI10.5067/SMP50-2NOCS
MeasurementOCEANS > SALINITY/DENSITY > SALINITY
Swath Width1000 km
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: JPL
Creator: JPL
Release Place: Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA91109, USA
Release Date: 2020-Dec-11
Resource: http://podaac.jpl.nasa.gov/smap

FormatHDF5
Keyword(s)JPLSMAPSSSV50, SMAP, SMAP-SSS, Soil Moisture Active Passive, salinity, polar, sun-synchronous, sss, psu, NASA, project, mission, JPL, CAP, combined active/passive, L2B
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
Resolution
Spatial Resolution: 25000 Meters x 25000 Meters
Temporal Resolution: Weekly - < Monthly
 
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
Granule Time Span: 2022-Jan-13 to 2024-Jul-22
Swath Width: 1000 km
 
Projection
Projection Type: Swath
Ellipsoid: WGS 84
 
NameLong NameUnit
anc_dirNCEP wind direction (oceanographic convention)Degrees
anc_spd10 meter NCEP wind speed (scaled by 1.03)Meters/second
anc_sssHYCOM salinityPSU
anc_sstNOAA Optimum Interpolation sea surface temperatureDegrees kelvin
anc_swhNOAA WaveWatch III significant wave heightMeters
antazi_aftAntenna azimuth angle aft lookDegrees
antazi_foreAntenna azimuth angle fore lookDegrees
azi_aftCell azimuth angle aft lookDegrees
azi_foreCell azimuth angle fore lookDegrees
ice_concentrationIce concentration
inc_aftCell incidence angle aft lookDegrees
inc_foreCell incidence angle fore lookDegrees
land_fraction_aftAverage land fraction for aft look
land_fraction_foreAverage land fraction for fore look
latlatitudeDegrees
lonlongitudeDegrees
n_h_aftNumber of L1B TBs aggregated into H-pol aft look
n_h_foreNumber of L1B TBs aggregated into H-pol fore look
n_v_aftNumber of L1B TBs aggregated into V-pol aft look
n_v_foreNumber of L1B TBs aggregated into V-pol fore look
nedt_h_aftAggregated noise equivilent Delta T for H-pol aft lookDegrees kelvin
nedt_h_foreAggregated noise equivilent Delta T for H-pol fore lookDegrees kelvin
nedt_v_aftAggregated noise equivilent Delta T for V-pol aft lookDegrees kelvin
nedt_v_foreAggregated noise equivilent Delta T for V-pol fore lookDegrees kelvin
num_ambiguitiesNumber of wind vector ambiguties
quality_flagQuality flag
row_timeApproximate observation time for each rowUTC seconds of day
smap_ambiguity_dirSMAP ambiguity wind direction using ancillary SSSDegrees
smap_ambiguity_spdSMAP ambiguity wind speed using ancillary SSSMeters/second
smap_high_dirSMAP wind direction using ancillary SSSDegrees
smap_high_dir_smoothSMAP wind direction using ancillary SSS and DIRTH smoothingDegrees
smap_high_spdSMAP wind speed using ancillary SSSMeters/second
smap_spdSMAP wind speedMeters/second
smap_sssSMAP sea surface salinityPSU
smap_sss_uncertaintySMAP sea surface salinity uncertaintyPSU
tb_h_aftAverage brightness temperature for all H-pol aft looksDegrees kelvin
tb_h_bias_adjBrightness temperature bias adjustment for H-polDegrees kelvin
tb_h_foreAverage brightness temperature for all H-pol fore looksDegrees kelvin
tb_v_aftAverage brightness temperature for all V-pol aft looksDegrees kelvin
tb_v_bias_adjBrightness temperature bias adjustment for V-polDegrees kelvin
tb_v_foreAverage brightness temperature for all V-pol fore looksDegrees kelvin
GENERAL DOCUMENTATION
USER'S GUIDE
ANOMALIES
DATA CITATION POLICY
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 JPL. 2020. JPL CAP SMAP Sea Surface Salinity Products. Ver. 5.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/SMP50-2NOCS

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For more information see Data Citations and Acknowledgments.
Journal Reference Fore,A.G, S.H. Yueh, W. Tang, B.W. Stiles, and A.K. Hayashi (2016). Combined Active/Passive Retrievals of Ocean Vector Wind and Sea Surface Salinity With SMAP. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 54, NO. 12. p.7396-7404. DOI: 10.1109/TGRS.2016.2601486

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