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Full catalog/SWOT_L2_RAD_GDR_D
SWOT_L2_RAD_GDR_D·vD·dataset

Water vapor and brightness over ocean, version D (SWOT)

SWOT Level 2 Radiometer Brightness Temperatures and Troposphere Data Product Version D
ocean NASA POCLOUD Level 2 netCDF-4
In plain English

What it measures. How much water vapor and liquid water are in the air over the ocean, with cloud water and wind speed alongside. This is the precise version, in an updated processing edition (Version D).

How it's made. Comes from the Advanced Microwave Radiometer on the SWOT satellite (NASA and CNES), processed with precise orbit data and final calibrations.

How & where you'd use it. Used to correct SWOT's ocean-surface-height measurements for atmospheric moisture; the accurate, reprocessed edition suited to careful analysis.

What's measured

OCEANS › SEA SURFACE TOPOGRAPHY › SEA SURFACE HEIGHTOCEANS › OCEAN WAVES › SIGNIFICANT WAVE HEIGHT

Coverage & cadence

  • Time span2022-12-16 → ongoing
  • Measured bySWOT (AMR)
  • Processing levelLevel 2
  • Spatial extent-180, -77.6, 180, 77.6
  • FormatsnetCDF-4
  • 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

The SWOT Level 2 Radiometer Brightness Temperatures and Troposphere Geophysical Data Record (GDR) dataset produced by the Surface Water and Ocean Topography (SWOT) mission provides atmospheric water vapor and liquid water content from the Advanced Microwave Radiometer (AMR), a Jason-class radiometer that measures sea surface brightness temperatures at three microwave frequencies (18.7, 23.8 and 34 GHz). Brightness temperatures are processed to estimate the wet troposphere content, atmospheric attenuation to backscatter, cloud liquid water, water vapor content, and wind speed coincident with each range measurement from the nadir altimeter and applied to correct for altimeter range delays caused by atmospheric effects. SWOT is a joint mission between NASA and CNES that launched on December 16, 2022 and aims to measure ocean surface topography with unprecedented resolution and accuracy, as well as map inland water bodies globally. This radiometer dataset consists of discrete measurements along two tracks located approximately 30-km to the left and right of the satellite nadir. The data were processed using the Precise Orbit Ephemeris (POE) and analyzed calibrations. The data are available with latency of < 90 days and distributed in netCDF-4 file format.

Get the data

swot_l2_rad_gdr_d_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="SWOT_L2_RAD_GDR_D",
    version="D",
    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.