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Full catalog/SMAP_JPL_L2B_NRT_SSS_CAP_V5
SMAP_JPL_L2B_NRT_SSS_CAP_V5·v5.0·dataset

How salty the sea surface is, near-real-time (SMAP)

JPL SMAP Level 2B Near Real-time CAP Sea Surface Salinity V5.0 Validated Dataset
ocean NASA POCLOUD Level 2 HDF5
In plain English

What it measures. How salty the sea surface is, plus extreme wind speed and direction, measured along the satellite's orbit track. Each file covers one roughly 98-minute orbit.

How it's made. Derived from the SMAP satellite's microwave brightness-temperature readings using a combined active-passive method from JPL; this validated near-real-time version arrives within about 6 hours.

How & where you'd use it. Helps monitor ocean salinity and strong winds in near-real-time, supporting studies of the water cycle, ocean circulation, and storms.

What's measured

OCEANS › SALINITY/DENSITY › SALINITY › SALINITY

Coverage & cadence

  • Time span2015-04-01 → ongoing
  • Measured bySMAP (SMAP L-BAND RADIOMETER)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF5
  • StatusACTIVE

What you can do with it

  • Watch sea-surface temperature and marine heatwaves
  • Spot algal blooms and ocean-colour shifts
  • Support fisheries and coastal monitoring
Official description

This 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.

Get the data

smap_jpl_l2b_nrt_sss_cap_v5_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="SMAP_JPL_L2B_NRT_SSS_CAP_V5",
    version="5.0",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from POCLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.