Satellite Observations of Arctic Change (SOAC)

The Arctic is one of the fastest changing places on Earth. The NSIDC Satellite Observations of Arctic Change (SOAC) transforms time series data from NASA satellites into interactive maps for you to visualize and study changes in the Arctic. SOAC maps show surface air temperatures, sea ice extent and age, snow cover, frozen ground, atmospheric water vapor, and vegetation greenness.

The maps perform best on a desktop or laptop computer with a high-speed internet connection.

How to use the maps

SOAC maps provide annual snapshots, and in most cases monthly snapshots of how conditions compare to long-term averages. For each interactive map, you can:

• Display a snapshot from the specific year, or month and year.
• Animate the maps over the course of the record, stopping and starting the animation at any point.
• See departures from the long-term average, for every month and year, in a time series graph.
• Zoom in and out using the + and – controls in the upper left corner of the screen. As you move the cursor over the map, a latitude/longitude display in the upper left corner of the screen gives the cursor's geographic location.

Types of maps

Near-Surface Air Temperatures: How much air temperatures deviate from the long-term average for each month and year

Snow Cover Duration: How long snow cover lasts in the Northern Hemisphere, and how much the duration deviates from the long-term average for that time of year

Sea Ice Concentration: How much the amount of sea ice in the Arctic Ocean varies from the average for each month and year

Sea Ice Age: How much sea ice covers the Arctic Ocean, its age, and how much the distribution of old versus young ice varies from average for each month and year

Non-Frozen Ground: How much the number of days each year departs from average for near-surface soil temperatures that have been above freezing

Water Vapor: How much the amount of atmospheric water vapor has diverged from the long-term average for each month and year

Vegetation Greenness: How much the greenness of Arctic vegetation has departed from the long-term average for each month and year

By comparing multiple maps, you can see how trends correlate with each other, for example, between changes in temperature and sea ice.

How the maps were made

NSIDC software developers collaborated with scientists to display the data on an interactive map grid centered on the North Pole, using intuitive color palettes for clarity. For each map pixel (the smallest area a satellite sensor observes) in each snapshot displayed, NSIDC has calculated how much the value for that pixel—hotter or colder, wetter or drier—deviates from the long-term average for that time of year.

Each interactive map is derived from one or more long-term observation records spanning decades. Data sets used in SOAC come from NASA, the National Oceanic and Atmospheric Administration (NOAA), the Rutgers Global Snow Lab, and NSIDC. More information about the underlying data record is provided in the individual map page, including access to the source data set.

Funding

The NASA Earth Science Cryosphere Sciences Program provided funds to create SOAC. NASA uses the vantage point of space to improve understanding of our home planet, improve the quality of life, and safeguard our future. The NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) supports the ongoing maintenance of SOAC.