Contents

Permafrost

Frozen Ground vs Permafrost

  • Seasonally frozen ground: freezes more than 15 days per year (The Ice Bowl)

  • Permafrost (permanently frozen ground): <= 0°C for at least 2 years (not necessary having water or ice!)

Permafrost Zones

../_images/permafrost_map.png

Fig. 4 Permafrost zones and locations for CO2 and methane flux measurements collected with eddy covariance (yellow) and chambers (blue). Source: EOS

Frozen Seafloor: Subsea Permafrost

Factors Affect Permafrost

  • Diurnal cycle

  • Seasonal cycle

  • Geographic location

  • Elevation

  • Landscape: snow (insulator), soil type, peat, plants (evergreen trees)

  • Slope

  • Lakes and rivers: heat source, talik

  • Radiation

Thawing Permafrost and Climate Change

  • Satellite observations (e.g., GRACE and ICESat)

  • Air temperature

  • Moisture

  • Active layer

  • Lakes

  • Ecosystem

  • Sea level

Biological and Human Activities and Permafrost

Permafrost and Carbon Cycle

  • Carbon dioxide

  • Methane

Snow Glaciers