Going Further

The NSIDC Sea Ice Index is a collection of summary data and browse imagery of monthly sea ice conditions. It is derived from raw data fields produced for one of NSIDC's products: "Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Passive Microwave Data"

To download the data

1. go to the website http://nsidc.org/data/nsidc-0051.html
2. Click on the "Access Data" button. You will be asked to fill out a User Registration Form, though this can be bypassed with a link in the upper right-hand corner of the page.
3. There are three directories, each for different time periods.
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Most of the data, the oldest data, are in "final-gsfc", more recent data from the end of the "final-gsfc" through ~3-6 months ago are in "preliminary", and the most recent data (the last 3-6 months) are in "near-real-time". The data in the "final-gsfc" folder was processed by scientists at the Goddard space flight center.
4. Click on the "final-gsfc' folder to select it.
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Within each directory, are subfolders by hemisphere and then by "daily" and "monthly". It will generally be easiest to work with monthly data. The time of each field is in the filename with the 4-digit year immediately followed by the 2-digit month (and then immediately followed by the 2-digit day of month for the daily data).
5. Select from the list of files and download by right clicking on the name of the file and saving it to your desktop.

A much simpler route is to download the data as a tar file.
To do so, simply copy and paste the ftp address below into a new window in your browser to access a compressed data set. South Polar
ftp://sidads.colorado.edu/pub/DATASETS/seaice/polar-stereo/nasateam/final-gsfc/south/monthly.tar North Polar
ftp://sidads.colorado.edu/pub/DATASETS/seaice/polar-stereo/nasateam/final-gsfc/north/monthly.tar