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Full catalog/SWOT_L2_LR_PreCalSSH_D
SWOT_L2_LR_PreCalSSH_D·vD·dataset

Sea surface height in fine detail (SWOT, pre-calibration)

SWOT Level 2 KaRIn Low Rate Sea Surface Height Pre Crossover Data Product, Version D
ocean NASA POCLOUD Level 2 netCDF-4
In plain English

What it measures. How high the sea surface stands across the global ocean, plus how big the waves are, in unusually fine detail. It covers a wide strip on each side of the satellite's path rather than just a single line.

How it's made. Produced from the SWOT satellite's KaRIn radar instrument; this is an early 'pre-calibration' version of the sea-surface-height data, gridded into swaths down to roughly 250-meter spacing.

How & where you'd use it. Helps researchers see ocean currents, eddies, and sea-level patterns in much greater detail than older satellites. As a pre-calibration product, it is mainly a research input rather than a polished everyday map.

What's measured

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

Coverage & cadence

  • Time span2022-12-16 → ongoing
  • Measured bySWOT (KaRIn, Jason-class Altimeter, AMR, DORIS, GPSP, LRA)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • 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 KaRIn Low Rate Precalibrated Sea Surface Height Data Product from the Surface Water Ocean Topography (SWOT) mission provides global sea surface height and significant wave height observations derived from low rate (LR) measurements from the Ka-band Radar Interferometer (KaRIn). SWOT launched on December 16, 2022 from Vandenberg Air Force Base in California into a 1-day repeat orbit for the "calibration" or "fast-sampling" phase of the mission, which completed in early July 2023. After the calibration phase, SWOT entered a 21-day repeat orbit in August 2023 to start the "science" phase of the mission, which is expected to continue through 2025. The L2 sea surface height data product is distributed in one netCDF-4 file per pass (half-orbit) covering the full KaRIn swath width, which spans 10-60km on each side of the nadir track. Sea surface height, sea surface height anomaly, wind speed, significant waveheight, and related parameters are provided on a geographically fixed, swath-aligned 2x2 km2 grid (Basic, Expert, Windwave). The sea surface height data are also provided on a finer 250x250 m2 "native" grid with minimal smoothing applied (Unsmoothed). This dataset is the parent collection to the following sub-collections: https://www.earthdata.nasa.gov/data/catalog/pocloud-swot-l2-lr-precalssh-basic-d-d https://www.earthdata.nasa.gov/data/catalog/pocloud-swot-l2-lr-precalssh-windwave-d-d https://www.earthdata.nasa.gov/data/catalog/pocloud-swot-l2-lr-precalssh-expert-d-d https://www.earthdata.nasa.gov/data/catalog/pocloud-swot-l2-lr-precalssh-unsmoothed-d-d

Get the data

swot_l2_lr_precalssh_d_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="SWOT_L2_LR_PreCalSSH_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.