Transpolar Drift

By: Danielle Holden

Background Moves from

Siberian Coast of Russia through Fram Strait and joins the Eastern Greenland Current

Moves at 1-3 cm/s Depth: 2000 m

Arctic Ocean circulation. Image courtesy of Arctic Monitoring and Assessment Programme (AMAP), Figure 3.29, AMAP (1998).

Ice/Fresh Water Circulation

Beaufort Gyre and Transpolar Drift “exchange” ice between each other

The amount of fresh water transported depends on how much ice was melted in the Arctic 50-70% albedo in Arctic Sensible heat loss into air

and ocean Transpolar Drift collides ice

into Greenland coast: ridge formation and thick ice

The amount of ice exportSource: Torben Königk et al: Fram Strait Ice Export: Variability and its Impact on Climate

Circulation and NAO Positive and Negative

Phases affect the Transpolar Drift differently: Positive phase: creates

westerlies in Arctic, colder air more sea ice, less ice and water transport

Negative phase: weak winds in Arctic, warmer air, less sea ice, more ice and water transport

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.QuickTime™ and a

TIFF (Uncompressed) decompressorare needed to see this picture.

Circulation and Vorticity Decadal Oscillations

between (+) and (-) vorticities

Positive and Negative vorticities affect where the current travels. There are 2 paths. Positive Vorticity Phase:

Weak High Pressure in Arctic allows fresh water/sea ice to drift counterclockwise. (RED)

Negative Vorticity Phase: Strong High Pressure forces fresh water clockwise (BLUE)

Transpolar Drift Paths:Source: Mysak: Patterns of Arctic Circulation

References http://www.giub.unibe.ch/klimet/wanner/nao.html http://nsidc.org/seaice/processes/circulation.html Knauss, John A. Introduction to Physical

Oceanography. Long Grove: Waveland Pr Inc, 2005.

Koenigk, T., J. Jungclaus, and U. Mikolajewicz. "Fram Strait Ice Export: Variability and its Impact on Climate." American Geohysical Union (2004).

Mysak, Lawrence A. "Patterns of Arctic Circulation." Science 293 (2001): 1269-270.