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Full catalog/SWOT_L2_NALT_GDR_2.0
SWOT_L2_NALT_GDR_2.0·v2.0·dataset

Sea surface height along the satellite track (SWOT altimeter)

SWOT Level 2 Nadir Altimeter Geophysical Data Record with Waveforms
ocean NASA POCLOUD Level 2 netCDF-4
In plain English

What it measures. Measures the height of the sea surface directly beneath the satellite, plus wave height and wind speed, recorded point by point along the satellite's path.

How it's made. Produced by the Poseidon-3C nadir altimeter on the NASA/CNES SWOT satellite, which times radar pulses bouncing off the sea; data are delivered as a calibrated geophysical record.

How & where you'd use it. Supports tracking of sea level, ocean conditions, and wave and wind states, and serves as a parent dataset feeding several more specialized sub-collections.

What's measured

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

Coverage & cadence

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

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 Nadir Altimeter Geophysical Data Record (GDR) with Waveforms dataset produced by the Surface Water and Ocean Topography (SWOT) mission provides sea surface height, significant wave height and wind speed measurements from the Poseidon-3C nadir altimeter, a Jason-class dual frequency (Ku/C) altimeter. SWOT is a joint mission between NASA and CNES that launched on December 16, 2022. It aims to measure ocean surface topography with unprecedented resolution and accuracy, as well as map inland water bodies globally. The GDR dataset consists of discrete measurements for each half orbit along the ground track with sampling resolutions of approximately 6-km and 300-m at 1Hz and 20Hz, respectively. The data were processed using restituted auxiliary data and the Precise Orbit Ephemeris (POE). The data are available with latency of < 90 days and distributed in netCDF-4 file format. This collection is the parent collection to the following sub-collections: https://podaac.jpl.nasa.gov/dataset/SWOT_L2_NALT_GDR_SSHA_2.0 https://podaac.jpl.nasa.gov/dataset/SWOT_L2_NALT_GDR_GDR_2.0 https://podaac.jpl.nasa.gov/dataset/SWOT_L2_NALT_GDR_SGDR_2.0

Get the data

swot_l2_nalt_gdr_2.0_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="SWOT_L2_NALT_GDR_2.0",
    version="2.0",
    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.