Interaction of katabatic winds and mesocyclones at the Eastern coast of Greenland 2001

Satellite images occasionally show the existence of MCs close to the Eastern coast of Greenland, especially in the region of Angmagssalik/Tasiilaq. The special characteristics of the East Greenland topography seem to be a key factor for the development of the MCs. The channeling of the flow in large valleys along the East Greenland coast leads to a convergence, implying a vertical stretching and the generation of cyclonic vorticity. This convergence can be strong during intense katabatic storms, so-called Piteraqs, which are a much-feared phenomenon in that area of Greenland (Rasmussen, 1989). A close relationship exists between the occurrence of Piteraqs and the generation of mesoscale vortices close to the East Greenland coast.

References:
Klein, T., Heinemann, G., 2001: Interaction of katabatic winds and mesocyclones at the Eastern coast of Greenland. In review by Meteorological Applications.
Rasmussen, L., 1989: Den dag, Angmagssalik naesten blaeste i havet. Vejret, 2, Danish Meteorological Society, 3-14.

Please click on the images for full resolution or animation.

Copyright by Günther Heinemann.

AVHRR channel 4
AVHRR channel 4
AVHRR channel 4
AVHRR channel 2
AVHRR channel 2 image with the region of the MC enlarged and for the full resolution HRPT image (1.1 km nadir, albedo greyscale in %).
LAM25 model 950 hPa for 1200 UTC 1 April 1997
Topography (isolines every 500 m) and geopotential height (isolines every 10 m, not shown above topography) and potential temperature (dashed isolines every 2 K) at 950 hPa for 1200 UTC 1 April 1997 (12 h LAM25 simulation) 'M' indicates the position of the MC southwest of Angmagssalik.
LAM25 model 950 hPa for 1200 UTC 2 April 97)
Topography (isolines every 500 m) and geopotential height (isolines every 10 m, not shown above topography) and potential temperature (dashed isolines every 2 K) at 950 hPa for 1200 UTC 2 April 97). 'M2' indicates the second MC south of Angmagssalik over the open water. The location of the first MC 'M' (24 h before) is also shown.