Sea Ice Index, Version 4
Data set id:
G02135
DOI: 10.7265/a98x-0f50
This is the most recent version of these data.
Version Summary
Version Summary
Initial release of Version 4. The data set now uses AMSR2 data as input.
Overview
Notice: Due to funding limitations, this data set was recently changed to a “Basic” Level of Service. Learn more about what this means for users and how you can share your story here: Level of Service Update for Data Products.
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.
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 EXTENT
ICE GROWTH/MELT
SEA ICE CONCENTRATION
Platform(s):
DMSP
DMSP 5D-3/F17
GCOM-W1
Nimbus-7
Sensor(s):
AMSR2
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 NorthEPSG:3411
- NSIDC Sea Ice Polar Stereographic SouthEPSG:3412
Spatial Coverage:
- N:-39.23S:-90E:180W:-180
- N:90S:30.98E:180W:-180
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
Data Access & Tools
Documentation
User Guide
NSIDC Special Reports
Help Articles
General Questions & FAQs
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
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: