How much of the sea is ice-covered (daily, 25 km) — AU_SI25

In plain English

What it measures. Daily polar maps of how much of the sea is covered by ice, plus the underlying microwave readings (how much natural microwave energy the surface gives off) at several frequencies for the Arctic and Antarctic.

How it's made. Produced from the AMSR-E and AMSR2 microwave instruments on the Aqua and GCOM-W1 satellites, with the two missions blended together and gridded onto 25 km polar maps, then run through an algorithm that turns the signal into ice cover.

How & where you'd use it. Monitoring shrinking and growing sea ice through the seasons and over years, supporting climate research, ship navigation and polar weather forecasting.

What's measured

SPECTRAL/ENGINEERING › MICROWAVE › BRIGHTNESS TEMPERATURECRYOSPHERE › SEA ICE › SEA ICE CONCENTRATION

Coverage & cadence

Time span2002-06-01 → 2011-10-04
Measured byAqua (AMSR-E) · GCOM-W1 (AMSR2)
Processing levelLevel 3
Spatial extent-180, 30.98, 180, 89.24
FormatsHDF-EOS5
StatusCOMPLETE

What you can do with it

Track deforestation, fire scars and land-cover change
Monitor crop and vegetation health (NDVI/EVI)
Map how built-up vs. green an area is over time

Official description

This data set reports average daily horizontally and vertically polarized brightness temperatures and sea ice concentrations on 25 km resolution north and south polar stereographic grids. The data are derived from observations acquired by the Advanced Microwave Scanning Radiometer (AMSR) for EOS (AMSR-E) and AMSR2 instruments that have been spatially resampled by the Japan Aerospace Exploration Agency (JAXA) to unify the AMSR-E and AMSR2 missions. Brightness temperatures are available at 6.9 GHz, 10.7 GHz, 18.7 GHz, 23.8 GHz, 36.5 GHz and 89.0 GHz for ascending and descending orbits, and as a single daily average. Sea ice concentrations are generated with the Enhanced NASA Team (NT2) algorithm; a separate variable reports the daily sea ice concentration difference between the legacy AMSR Basic Bootstrap Algorithm (ABA) and the NT2.

Get the data

au_si25_access.py

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

results = earthaccess.search_data(
    short_name="AU_SI25",
    version="1",
    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.

Official links

Search and order NASA Earth Science data using spatial and temporal filters. Reformatting, reprojecting, and subsetting options are available for some data sets. GET DATA
Quickly download a few files using a web browser, or access data through a command-line utility such as WGET. GET DATA
Search data by spatial and/or temporal ranges or file name. Choose from various download options, including a Python script. GET DATA
A Python library to search and access NASA Earth science data with just a few lines of code GET DATA
Find more data access options and help resources. VIEW RELATED INFORMATION
AMSR-E/AMSR2 Unified L3 Daily 25 km Brightness Temperatures & Sea Ice Concentration Polar Grids, Version 1 User Guide VIEW RELATED INFORMATION
AMSR2 Sea Ice Algorithm Theoretical Basis Document VIEW RELATED INFORMATION
The AMSR-E NT2 Sea Ice Concentration Algorithm: its Basis and Implementation VIEW RELATED INFORMATION