 |
| Titel |
Fram Strait ice area export and its influence on Arctic sea ice thickness |
| VerfasserIn |
Mari Hegland Halvorsen, Lars Henrik Smedsrud |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087691
|
| Publikation (Nr.) |
 EGU/EGU2014-1751.pdf |
|
|
|
|
|
| Zusammenfassung |
| Arctic sea ice loss is one of the most visible changes related to global warming. A number of
processes can contribute to Arctic Sea Ice variability, and one of them is changes in the ice
export between Svalbard and Greenland in the Fram Strait. We study long-term changes in
Arctic Sea Ice thickness from 1871 - 2012, using a coupled air-ice-ocean column model of
the deep Arctic Ocean.
Using monthly mean sea level pressure observations from Svalbard from the Norwegian
Meteorological Institute, and from Greenland from the Danish Meteorological Institute, Fram
Strait ice area export has been estimated from 1935 - 2012. High resolution ice drift velocity
across 79°N from 2004 to 2010 has been derived from radar satellite data. A linear regression
between ice drift velocity and geostrophic wind from pressure observations resulted in an ice
drift velocity being 1.1% of the geostrophic wind, with the East Greenland current
contributing with a constant speed of 8.5 cm s-1. We use geostrophic winds derived from
pressure observations also to estimate the Fram Strait ice area export from 1935
- 2012, finding that the ice export has been increasing 1.5 ± 1.1 % per decade.
This increase led to a negative trend in the annual mean Arctic Sea Ice thickness
of -1.4 ± 0.2 % per decade from 1950 - 2012, from approximately 3.6 m to 3.25
m.
Using mean sea level pressure data from the 20th Century Reanalysis Project,
Fram Strait ice drift velocity was found to be 1.3% of the geostrophic wind, with a
constant term of 7.6 cm s-1. The resulting ice area export was calculated from 1871 -
2011, giving no overall trend. We find that the annual mean Arctic Sea Ice thickness
decreased approximately 50 cm from late 1920’s to mid 1990’s, and has been slightly
increasing in recent years. The long-term trend from 1900 - 2011 is -1.0 ± 0.1
% per decade, and the trend from 1950 - 2011 is -0.3 ± 0.3 % per decade. The
annual mean Arctic Sea Ice thickness based on reanalysis is lower than that based on
observed surface pressure for 1935 - 2005, but similar for the last few years. Fram
Strait ice export is thus an important contributor to Arctic Sea Ice loss over the last
century. |
|
|
|
|
|
|