Permafrost is a layer of ground that remains frozen all year round. It often sits beneath a layer of soil that thaws seasonally. Due to rising temperatures, some areas of permafrost are thawing for the first time in years, which releases gases and organic carbon that have profound effects on the surrounding ecosystem. Thawing permafrost can also lead to landslides and erosion that pose danger for infrastructure and wildlife.

Instruments aboard NASA’s Earth-observing satellites cannot measure permafrost directly, but they can collect soil moisture data through radiometry. This helps scientists estimate the status of permafrost around the world. NASA’s data useful to the study of permafrost also include measures of soil carbon, estimates of permafrost active layer thickness, vegetation data, temperature data, and land surface data.