Geoscience Reference
In-Depth Information
Figure 6.5.
Annual accumulation
over the Greenland Ice Sheet in
mm water equivalent. The contour
intervals are 200 mm, but 100 mm if
smaller than 400 mm and 600 mm
if larger than 1000 mm (from
Chen et al.,
1997
, by permission
of AMS).
6.1.3
Precipitation over Greenland
Direct observations of precipitation over Greenland are particularly scanty. Stations
with long records are limited to the coasts. As noted earlier, over the past couple
of decades, data over the ice sheet have been acquired from automatic weather sta-
tions. But quite a few measurements have been made of annual snow accumulation
over the ice sheet. G. Bender (
1984
) provides a synthesis of observed annual accu-
mulation (snow water equivalent) over the ice sheet, modified along the coast with
a simple model of orographic precipitation. The resulting map, further modified by
Bromwich, Keen, and Bolzan (
1993
) is provided as
Figure 6.5
. This is a much bet-
ter analysis than can be provided from interpolating sparse station data and other
coarse resolution records. The main features of the map are very low accumulation
(100 mm) over the northern portions of the island with the highest values along the
southeast coast linked to orographic precipitation. Peak values along the southeast
coast exceed 2,000 mm. These local features are not captured in
Figure 2.25
. Fairly
high accumulations values are also found along the western coast related to oro-
graphic uplift and cyclone activity in the Davis Strait.
A somewhat more recent effort to assess Greenland precipitation comes from
the study of Bromwich et al. (
2001
). It is based on enhancements to the dynamic
model of Chen et al. (
1997
). The model is based on the omega equation (which
