How much of the sea is ice-covered — NSIDC-0051

In plain English

What it measures. What fraction of each ocean area is covered by sea ice, mapped on a 25-kilometer grid over the polar regions, as a consistent record stretching back to 1978.

How it's made. Worked out from microwave energy naturally given off by the surface, recorded by a series of satellite sensors and stitched together into one long, comparable time series.

How & where you'd use it. A backbone dataset for monitoring shrinking and growing polar ice, studying climate change, and tracking long-term trends in the Arctic and Antarctic.

What's measured

CRYOSPHERE › SEA ICE › SEA ICE CONCENTRATION

Coverage & cadence

Time span1978-10-26 → 2025-12-31
Measured byDMSP 5D-2/F11 (SSM/I) · DMSP 5D-2/F13 (SSM/I) · DMSP 5D-2/F8 (SSM/I) · DMSP 5D-3/F17 (SSMIS) · Nimbus-7 (SMMR)
Processing levelLevel 3
Spatial extent-180, -90, 180, -39.23
FormatsPNG, netCDF-4
StatusCOMPLETE

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 is generated from brightness temperature data and is designed to provide a consistent time series of sea ice concentrations spanning the coverage of several passive microwave instruments.The data are provided in the polar stereographic projection at a grid cell size of 25 x 25 km. Data coverage began on 26 October 1978 and is ongoing through the most current processing, with updated data processed several times annually.

Get the data

nsidc-0051_access.py

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

results = earthaccess.search_data(
    short_name="NSIDC-0051",
    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.

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
Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data, Version 2 User Guide VIEW RELATED INFORMATION
An Improved Land Mask for the SSM/I Grid - NASA-TM-104625 VIEW RELATED INFORMATION
SMMR, SSM/I, and SSMIS Sensors Summary VIEW RELATED INFORMATION