Generated using version 3.0 of the official AMS LATEX template Controls on Arctic sea ice from first-year and multi-year ice survivability

• Main Authors: Kyle C. Armour, Cecilia M. Bitz, Luanne Thompson, Elizabeth C. Hunke
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.649.5893; http://www.atmos.washington.edu/~bitz/Armour_etalpreprint.pdf

Recent observations of Arctic sea ice show that the decrease in summer ice cover over the last few decades has occurred in conjunction with a significant loss of multi-year ice. The transition to an Arctic that is populated by thinner, first-year sea ice has important implica-tions for future trends in area and volume. Here, we develop a reduced model for Arctic sea ice with which we investigate how the survivability of first-year and multi-year ice control the mean state, variability, and trends in ice area and volume. A hindcast with a global dynamic-thermodynamic sea ice model that traces first-year and multi-year ice is used to estimate the survivability of each ice type. These estimates of survivability, in concert with the reduced model, yield a persistence time scale of September area and volume anomalies and the characteristics of the sensitivity of sea ice to climate forcing that compare well with a fully coupled climate model. The September area is found to be nearly in equilibrium with climate forcing at all times, and therefore the observed decline in summer sea ice cover is a clear indication of a changing climate. Keeping an account of first-year and multi-year ice area within global climate models offers a powerful way to evaluate those models with observations, and could help to constrain projections of sea ice decline in a warming climate. 1 1.