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Full catalog/ATL21
ATL21·v004·dataset

How sea level changes near the poles (ICESat-2)

ATLAS/ICESat-2 L3B Daily and Monthly Gridded Polar Sea Surface Height Anomaly V004
ocean NASA NSIDC_CPRD Level 3 active HDF5
In plain English

What it measures. Daily and monthly gridded maps of how much sea level rises and falls (sea surface height anomalies) in the polar regions.

How it's made. Derived from ICESat-2 laser measurements of sea-ice freeboard, gridded over the poles daily and monthly.

How & where you'd use it. Useful for studying polar ocean circulation, sea-level change, and the link between ice and ocean in the Arctic and Antarctic.

What's measured

OCEANS › SEA SURFACE TOPOGRAPHY › SEA SURFACE HEIGHT › SEA SURFACE HEIGHT ANOMALY (SSHA)

Coverage & cadence

  • Time span2018-10-14 → ongoing
  • Measured byICESat-2 (ATLAS)
  • Processing levelLevel 3
  • Spatial extent-180, 37, 180, 89
  • 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

ATL21 contains daily and monthly gridded polar sea surface height anomalies, derived from ATLAS/ICESat-2 L3A Sea Ice Freeboard (ATL10) along-track freeboard estimates.

Get the data

atl21_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="ATL21",
    version="004",
    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 NSIDC_CPRD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.