Get Data


Data can be downloaded through a Web browser or command line via FTP. When using a Web browser, the FTP link first directs you to an Optional Registration Form that if filled out, will allow you to receive notifications about updates or processing changes related to that specific data set. After completing the Optional Registration Form, the FTP directory becomes available. For additional help downloading data through an FTP client, go to the How to access data using an FTP client support page.


Data Set ID:

IMS Daily Northern Hemisphere Snow and Ice Analysis at 1 km, 4 km, and 24 km Resolutions, Version 1

This data set provides snow and ice cover maps for the Northern Hemisphere from February 1997 to the present from the National Ice Center's Interactive Multisensor Snow and Ice Mapping System (IMS). It is derived from a variety of data products including satellite imagery and in situ data. The data are provided in ASCII text and GeoTIFF formats in three different resolutions: 1 km, 4 km, and 24 km.

Note: The IMS product is considered an operational product; however, NIC, who creates this product, does not guarantee availability or timely delivery of data via the NIC Web server. NSIDC, as the data archive, does not guarantee availability of this product via the NSIDC Web server. These servers should not be used to support operational observation, forecasting, emergency, or disaster mitigation operations, either public or private. Users with real-time operational needs should visit the NIC Web site and contact the National Ice Center Liaison to request access to their operational server.

Geographic Coverage

  • Snow/Ice > Ice Extent
  • Snow/Ice > Snow Cover
Spatial Coverage:
  • N: 90, S: 0, E: 180, W: -180

Spatial Resolution:
  • 1 km x 1 km
  • 4 km x 4 km
  • 24 km x 24 km
Temporal Coverage:
  • 4 February 1997
(updated daily)
Temporal Resolution: 1 day
Data Format(s):
  • GIF
  • GeoTIFF
  • ASCII Text
Platform(s) AQUA, DMSP, DMSP 5D-3/F17, GMS-5, GOES-10, GOES-11, GOES-13, GOES-9, MSG, NOAA-14, NOAA-15, NOAA-16, NOAA-17, NOAA-18, NOAA-N, RADARSAT-2, TERRA
Version: V1
Data Contributor(s): National Ice Center.

Data Citation

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

National Ice Center. 2008, updated daily. IMS Daily Northern Hemisphere Snow and Ice Analysis at 1 km, 4 km, and 24 km Resolutions, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: [Date Accessed].
No technical references available for this data set.


Why can't I convert IMS ascii data into a raster in ArcMap?

The problem is that some IMS ascii files were created without spaces in the text in the columns and rows. ArcMap won't read it unless there are spaces (for example)

00000011112220000 - ArcMap won't read
0 0 0 0 0 1 1 1 1 1 2 2 2 - ArcMap will read

You will need to... read more

How To

How can I plot IMS-24km ASCII data using General Mapping Tools (GMT)?

There are two "tricks" to using this dataset with GMT: reading the data into a GMT grdfile, and knowing the projection to use when plotting data
over the gridded image.

First, the ASCII files have a 30-line header, then single-digit values all strung together. GMT's xyz2grd... read more