Geoscience Reference
In-Depth Information
Figure 4.9.
Cyclone frequency (cyclone passages per month) for winter, spring,
summer, and autumn over the 1970-1999 period, based on NCEP/NCAR data (by the
authors).
take a northerly to easterly track. Activity peaks in the vicinity of the Icelandic
Low. Another area of high cyclone frequencies is Baffin Bay. While cyclones are
of course very common in the vicinity of the Aleutian Low, relatively few of these
Pacific-side systems migrate into the Arctic. Relatively few closed lows are found
over the central Greenland Ice Sheet. Zhang et al. (
2004
) provide similar results. In
comparison to the early view of Pettersen (
1950
), based on limited data sources, it
is clear that although winter cyclones over the central Arctic Ocean are infrequent
in comparison to the Atlantic sector, they are by no means rare.
The winter Icelandic Low and the region extending into the Barents Sea is also a
region of frequent cyclogenesis and system deepening (the deepening rate is a use-
ful measure of cyclone intensification). The entire area is characterized by enhanced
baroclinicity (strong temperature gradients). Rapid deepening of lows along the ice
edge is frequently observed (Serreze,
1995
; Serreze et al.,
1997
). Redevelopment of
