Sea Ice Index, Version 3

Data set id:

G02135

DOI: 10.7265/N5K072F8

This is the most recent version of these data.
Version Summary

Updated the method used to calculate the monthly average sea ice extent and area data values.

Overview

The Sea Ice Index provides a quick look at Arctic- and Antarctic-wide changes in sea ice. It is a source for consistent, up-to-date sea ice extent and concentration images, in PNG format, and data values, in GeoTIFF and ASCII text files, from November 1978 to the present. Sea Ice Index images also depict trends and anomalies in ice cover calculated using a 30-year reference period of 1981 through 2010. The images and data are produced in a consistent way that makes the Index time-series appropriate for use when looking at long-term trends in sea ice cover. Both monthly and daily products are available. However, monthly products are better to use for long-term trend analysis because errors in the daily product tend to be averaged out in the monthly product and because day-to-day variations are often the result of short-term weather.

Parameter(s):

ICE EXTENTICE GROWTH/MELTSEA ICE CONCENTRATION

Platform(s):

DMSP, DMSP 5D-3/F17, DMSP 5D-3/F18, Nimbus-7

Sensor(s):

SMMR, SSM/I, SSMIS

Data Format(s):

PNG, GeoTIFF, CSV, Shapefile

Temporal Coverage:

26 October 1978 to present

Temporal Resolution:

1 day

Spatial Resolution:

25 km

25 km

Spatial Reference System(s):

NSIDC Sea Ice Polar Stereographic North

EPSG:3411

NSIDC Sea Ice Polar Stereographic South

EPSG:3412

Spatial Coverage:

N:

-39.23

S:

-90

E:

180

W:

-180

N:

90

S:

30.98

E:

180

W:

-180

Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.

View Metadata Record

Data Access & Tools

Documentation

Help Articles

General Questions & FAQs

Are the same regions used in the Sea Ice Index and MASIE-NH?

The regions differ slightly between the Sea Ice Index and the Multisensor Analyzed Sea Ice Extent - Northern Hemisphere (MASIE-NH). The two data sets are a source for sea ice extent, but they use different methods and data to estimate this parameter and their intended uses are also different.

NSIDC currently archives passive microwave sea ice concentration products based on two algorithms: the NASA Team algorithm and the Bootstrap algorithm. Both algorithms were developed by researchers at the NASA Goddard Space Flight Center in the 1980s.

The Sea Ice Index and the Arctic Sea Ice News Analysis (ASINA) Web pages provide images derived from passive microwave satellite data that depict the most recent daily sea ice conditions.

If you plot the average daily change in sea ice extent in the northern hemisphere, based on the data from 'Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx', you may notice that at the beginning of each month, particularly in the summer, the daily change is larger.

How to Articles

Guide to the NSIDC Data Map Services API

The NSIDC Data Map Services Application Programming Interface (API) provides HTTP URLs for requesting geo-registered map images from NSIDC's geospatial database. A WMS request defines the geographic layer(s) and area of interest to be processed.

NOAA@NSIDC data recently transitioned to HTTPS. The directory structure has NOT changed, but the beginning of the URL has changed from: ftp://sidads.colorado.edu/pub/DATASETS/ to: