climate change on UAE - Stockholm Environment Institute-US Center

Proejected Changes in precipitation from 1980-99 to 2090-99
December-
February
Percent
Change
+20
+10
+5
-5
June-
August
-10
-20
unclear
Change
Figure ‎3‐4. Statistical summary of projected patterns of precipitation <strong>change</strong> from multiple General
Circulation Models for December, January and February (left) and June, July, and August (right).
in computing capability, it is still very time
consuming and costly to use these models
to simulate future <strong>climate</strong>s. One of the most
important compromises for achieving model
results in a reasonable amount of time is to
decrease the model’s horizontal resolution.
This limitation means that it is prohibitively
costly to run a GCM at a spatial resolution that
would accurately depict the effects of mountains
and other complex surface features on regional
<strong>climate</strong>s.
The problem with such a coarse horizontal
resolution is that important processes occurring
at finer scales are not well defined. Topography,
for example, is very important in determining
the location of precipitation. As moist air
rises over mountains or hills, the moisture
condenses, producing clouds and, if conditions
are right, precipitation. Although there has
been marked improvement over the last three
decades in the simulation of precipitation, it is
still not well represented in GCMs, especially
in areas of complex topographies, since the
coarse horizontal resolution of GCMs tends
to smooth out important landscape features
that affect atmospheric processes. At the
resolution of most GCMs the models do not
adequately represent the Oman Mountains and
if they do, they are simply gentle ridges and do
not resolve finer scale features that influence
regional <strong>climate</strong>. Clearly, that level of spatial
resolution is too coarse to reproduce the effects
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Climate Change Impacts, Vulnerability & Adaptation