Study on recent Arctic sea ice loss and its impact on the heat budget as well as on the large scale

• Main Authors: Tido Semmler, Phd Raymond Mcgrath Shiyu Wang, Suggested Reviewers, Juergen Bader Phd, Michel Deque, James E Overland Phd, Circulation Magdalena A Balmaseda
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Article Type; Special Issue; EC-Earth Keywords; Arctic sea ice; Arctic energy budget; sensitivity study; Northern mid-latitude climate; sea ice loss; reduced meridional temperature gradient; climate model; Arctic; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.230.5778; http://ecearth.knmi.nl/Semmleretal.pdf

Abstract: The atmospheric general circulation model EC-EARTH-IFS has been applied to investigate the influence of both a reduced and a removed Arctic sea ice cover and therefore a reduced meridional temperature gradient on the climate of the Northern mid-latitudes. Three 40-year simulations driven by original and modified ERA-40 sea surface temperatures and sea ice distributions have been performed at T255L62 resolution, corresponding to about 50 km horizontal resolution. Simulated changes between sensitivity and reference experiments are most pronounced over the Arctic itself where the reduced or removed sea ice leads to strongly increased upward heat and longwave radiation fluxes and precipitation in winter. In summer, the most pronounced change is the stronger absorption of shortwave radiation which is enhanced by optically thinner clouds. Averaged over the year and over the area north of 70 ° N, the negative energy imbalance at the top of the atmosphere decreases by about 10 W/m2 in both sensitivity experiments. The energy transport across 70 ° N is reduced as a result of the decreased temperature gradient. Changes are not restricted to the Arctic. A weaker pressure gradient, less extreme cold events and less precipitation are simulated in sub-Arctic and Northern midlatitude