Geoscience Reference
In-Depth Information
Figure 4.10.
Cyclogenesis counts for winter, spring, summer and autumn over the
1970-1999 period, based on NCEP/NCAR data (by the authors).
extratropical systems migrating from the south is common between Greenland and
Iceland. Serreze et al. (
1997
) find that roughly half of all cyclones associated with
the Icelandic Low form north of 55°N. Another interesting phenomenon is bifurca-
tion (splitting) of lows moving in from the south and southwest by the high ice sheet
barrier (elevations at about 64
o
N, near the southern tip of Greenland exceed 2,800
m, roughly the 700-hPa level), with one of the low pressure centers migrating pole-
ward into Baffin Bay along the west coast of Greenland, with the other migrating
poleward along the east coast of Greenland.
As shown by Tsukernik, Kendig, and Serreze (
2007
), strong deepening of
cyclones in the Atlantic sector tends to occur in three preferred regions: (1) south of
Greenland, at about 54
o
N; (2) near the locus of the mean Icelandic Low; and (3) just
south of Svalbard. The area of preferred deepening south of Greenland is located in
a region of maximum gradients in 500 hPa height just east of the axis of the mean
eastern North American 500 hPa trough, where there tends to be positive vorticity
