Going Further

The National Snow and Ice Data Center (NSIDC) has many opportunities for further exploration. Here are a few ideas to try.

• Examine the sea ice data downloaded in this lesson for variations in concentration.
• Examine sea ice in the Antarctic Region—compare fluctuations and seasonality. Use either the online animations or access the data sets from the ftp site referred to in the chapter.
• Add wind pattern data to the sea ice data and explore relationships between these two factors.

Antarctic Sea Ice data can be also be downloaded from the NSIDC website. Antarctic sea ice is in the same directories, but it is in the "South" folders.

An important difference is when you import the Antarctic fields: the images are 316 by 332 pixels instead of the values used for the Arctic.

Show me how to access and download other data

Hide

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.
Show me more about the directory structure
Hide
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.
Show me more about the directory structure
Hide
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 Data
  ftp://sidads.colorado.edu/pub/DATASETS/seaice/polar-stereo/nasateam/final-gsfc/south/monthly.tar
• North Polar Data
  ftp://sidads.colorado.edu/pub/DATASETS/seaice/polar-stereo/nasateam/final-gsfc/north/monthly.tar

Google Earth software can be used for visualization of this data.
Data sets in KMZ format (for Google Earth) can be downloaded at NSIDC Data on Virtual Globes: Google Earth

Sea Ice data can be viewed and animated online using the NSIDC Sea Ice Animation Tool

Other EET chapters that utilize ImageJ as a tool and satellite imagery as a data source include the following:

• Annotating Change in Satellite Images—Use time-series images to produce a map documenting land use changes in China.
• Analyzing the Antarctic Ozone Hole—Measure and graph the area of depleted ozone from Total Ozone Mapping Spectrometer (TOMS) images.
• Exploring Albedo with NASA NEO and ImageJ—Use ImageJ to explore and animate satellite images of albedo, snow cover, and land surface temperature downloaded from the NASA Earth Observation (NEO) Web site. Then use NEO's Image Composite Editor (ICE) to observe, graph, and analyze the relationship between these three variables.
• Measuring Distance and Area in Satellite Images—Use ImageJ to quantify change over time in satellite images.
• Shrinking Forest - Growing Problem—Process and measure time-series SAR images to analyze the rate of deforestation in the Amazon rainforest. Produce a color composite image showing the oldest to most recently deforested areas.

Resources and Further Information

• NSIDC Education and Outreach page
• Alaska Sea Ice story tells the story from the point of view of a Canada goose.
• International Polar Year NASA website
• Students on Ice—Trip to the Arctic 2007 has journal entries, photos and movies to supplement this chapter.

Additional Reference Papers

• Bridging perspectives from remote sensing and Inuit communities on changing sea-ice cover in the Baffin Bay region - Meier, Stroeve and Gearheard, 2006
  download this file (Acrobat (PDF) 245kB Jul5 07)