Ice Bridge Arctic Sea Ice Thickness Observations 2009

Ice. Bridge Arctic Sea Ice Thickness Observations: 2009 -2013 Jackie Richter-Menge and Sinéad Farrell With support from the entire Ice. Bridge Team From: Richter-Menge and Farrell (2013) GRL

Sea Ice Thickness in the Western Arctic: 2009 - 2013 2009 2010 2011 2012 From: Richter-Menge and Farrell (2013), GRL • Regional analysis: Central Arctic (Black) Beaufort Sea (Red) • Ice. Bridge coverage variable ‒ Spatially (increasing) ‒ Ice type 2013 2

Regional Ice Thickness (2009 – 2013) From: Richter-Menge and Farrell (2013), GRL 3

Regional Ice Thickness Results (2009 – 2013) Central Arctic • Multiyear (MY) ice zone dominates: ≥ 90% • Mean (modal) thickness 3. 2 m (2. 4 m); interannual variability observed Beaufort /Chukchi Sea (BC) Region: • Mix of MY and first-year (FY) ice • ~ 25 % MY : 75 % FY ice, distribution varies over 5 year period • Mean (modal) thickness: 2. 0 m (1. 9 m); decrease observed after 2011. • Mean thickness may have decreased from ~ 2. 5 m to as low as 1. 6 m. • Very thin ice in Chukchi Sea: 0 – 1 m, following Feb. 2013 breakout event • Decrease in MY in both sectors in 2011, that persisted thereafter Longview • Sea Ice Thickness in Central Arctic has remained consistent over last five years after precipitous drop in 2007/2008 • Possible decrease in mean thickness in Beaufort/Chukchi region From: Richter-Menge and Farrell, 2013, GRL 4