Where sea ice covers the ocean (NOAA-21, daily, 375 m)

In plain English

What it measures. Daily maps showing where the ocean is covered by sea ice and how far that ice extends, at a resolution of about 375 meters per pixel.

How it's made. Built from light and energy readings captured by the VIIRS instrument on the NOAA-21 satellite, which are converted into a snow-and-ice index to flag icy areas.

How & where you'd use it. Helps track the day-to-day spread and retreat of sea ice, useful for navigation, climate monitoring, and watching polar conditions over time.

What's measured

CRYOSPHERE › SEA ICE

Coverage & cadence

Time span2023-02-10 → ongoing
Measured byJPSS-2 (VIIRS) · NOAA-21 (VIIRS)
Processing levelLevel 3
Spatial extent-180, -90, 180, 90
FormatsHDF-EOS5
StatusACTIVE

What you can do with it

Measure sea ice, snow cover and glaciers
Watch ice-sheet elevation change
Track freeze/thaw and permafrost

Official description

This data set reports sea ice cover/extent derived from radiance data acquired by the Visible Infrared Imager Radiometer Suite (VIIRS). Following the approach used by MODIS, the algorithm converts VIIRS calibrated radiances into brightness temperature and computes sea ice cover using Normalized Difference Snow Index (NDSI). VIIRS flies on board the Joint Polar Satellite System 2 (JPSS-2), also known as NOAA-21.

Get the data

vj229p1d_access.py

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

results = earthaccess.search_data(
    short_name="VJ229P1D",
    version="2",
    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.

What's measured

Coverage & cadence

What you can do with it

Get the data

Official links