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Full catalog/TOPEX_POSEIDON_GDR_F
TOPEX_POSEIDON_GDR_F·vF·dataset

How high the sea surface stands (TOPEX/Poseidon)

TOPEX/POSEIDON Geophysical Data Record Version F
ocean NASA POCLOUD Level 2 netCDF-4
In plain English

What it measures. Precise measurements of sea surface height across the global ocean, plus related quantities like wave height and the corrections needed to interpret the data. Records hold over a hundred parameters for each second of measurement.

How it's made. Collected by the radar altimeters on the joint NASA/French TOPEX/Poseidon satellite, launched in 1992, and delivered as data records rather than ready-made images.

How & where you'd use it. A research-grade product for studying ocean topography, sea level, and ocean circulation; users must do their own processing to turn it into sea-surface-height maps.

What's measured

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

Coverage & cadence

  • Time span1992-10-13 → 2005-10-04
  • Measured byTOPEX/POSEIDON (ALT (TOPEX), TMR)
  • Processing levelLevel 2
  • Spatial extent-180, -66, 180, 66
  • FormatsnetCDF-4
  • StatusCOMPLETE

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 TOPEX/POSEIDON Geophysical Data Record (GDR) contains global coverage altimeter data. The objective of the TOPEX/POSEIDON mission, launched in August 1992, is to determine ocean topography with a sea surface height measurement precision of 3 cm and a sealevel measurement accuracy of 13 cm. The dataset contains measurements from two altimeters, a NASA dual frequency (Ku and C band) instrument similar to the Geosat altimeter, and a French space agency (CNES) instrument which is a proof-of-concept solid-state altimeter (Ku band). It also contains Sea Surface Height (SSH), significant wave height, ionospheric correction, tides and other geophysical corrections. It is emphasized that this product is considered research data because of the form and content of the data. The data consist entirely of files comprising headers and data records which contain over a hundred parameters for each second. It is swath data and there are no images. Analysis software is the responsibility of the user. Calculation of sea surface height anomalies from the altimeter range and environmental corrections is the responsibility of the user. The data are arranged in 10 day cycles that are separated into 254 passes, each about 56 minutes.

Get the data

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

results = earthaccess.search_data(
    short_name="TOPEX_POSEIDON_GDR_F",
    version="F",
    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.