In uence of Initial Conditions and Climate Forcing1 on Predicting Arctic Sea Ice2 E. Blanchard-Wrigglesworth, 1

• Main Authors: C. M. Bitz, M. M. Holl
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Blanchard; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.646.2932; http://www.atmos.washington.edu/~bitz/Blanchard_etal2011b.pdf

The recent sharp decline in Arctic sea ice has triggered an increase in the3 interest of Arctic sea ice predictability, not least driven by the potential of4 significant human industrial activity in the region. In this study we quan-5 tify how long Arctic sea ice predictability is dominated by dependence on6 its initial conditions versus dependence on its secular decline in a state-of-7 the-art global circulation model (GCM) under a ‘perfect model ’ assumption.8 We demonstrate initial-value predictability of pan-Arctic sea ice area is con-9 tinuous for 1-2 years, after which predictability is intermittent in the 2-4 year10 range. Predictability of area at these longer lead times is associated with strong11 area-thickness coupling in the summer season. Initial-value predictability of12 pan-Arctic sea ice volume is significant continuously for 3-4 years, after which13 time predictability from secular trends dominates. Thus we conclude predictabil-14 ity of Arctic sea ice beyond 3 years is dominated by climate forcing rather15 than initial conditions. Additionally, we find that forecast of summer con-16 ditions are equally good from the previous September or January initial con-17 ditions.18