Lars H. Smedsrud
Associate Professor, Geophysical Institute, University of Bergen
Modeling the Arctic Ice Cover; A coupled
air-ice-ocean culumn model has been very useful in a number of studies.
The important processes are included, and results indicate that
the sea ice export is a stronger driver of thinning for the ice than
the estimated increased oceanic heat transport. Heat transport in the
atmosphere have remained on the same level as around 1990 and cannot
explain the recent ice loss. Satellitte images show that the ice export has increased steadily since
2004, and a paper in The Cryosphere has all the details. If the ice export remains as high as presently the Arctic
ice-cover will remain close to the present level. But, if the export
decrease to the previous lower level, the Arctic ice-cover could
recover significantly. On longer timescales increase in radiation due
to increased green house gases leads to a 95 % open water situation
during summer 2050 (a 2*CO2 scenario). First results were descibed in a
Geophysical Research Letter and these were sort of confirmed in a new study in Ocean Modelling.
Sea ice formation in open water; I study how the first ice formation depend on the surrounding forcing, mostly the wind speed creating turbulence in the ocean, snow drift and high heatfluxes to the cold air above. If the first ice cover becomes a thin layer of solid ice rather than a layer of slush, heat fluxes will be an order of magnitude lower, and less salt will be released to the ocean below. The first field work in Polar Ocean Climate Processes took place in March 2003 in Svea. The next three field seasons were spent at a cabin on Edge Øya in Storfjorden. If you have a good internet connection (> 1 Mbit/s) and Windows Media Player, you may watch a film from the fieldwork: "When the ice comes". Scientific results may be found in a Cold Regions Science and Technology article. When sea water freezes and the water is sufficiently turbulent from wind or tides, frazil ice formation will be the result. These crystals look much like snow flakes, and are diffused down into the water. They contribute to a more efficient ice formation and thereby also a higher salt flux then during normal congelation ice growth. Frazil ice forms in rivers, in leads or polynyas, and below Antarctic ice shelves. Image of congealed frazil ice.
Previous administrative duties;
Forum for Research into Ice Shelf Processes (FRISP) www pages and editor of reports 2002-2007
Norwegian Ocean and Climate Project, NOClim and Polar Ocean Climate Processes, ProClim www pages, and outreach
Lars Henrik Smedsrud