Modelisation

Andrew Bush (co-PI), Ted Pollock (MSc), Emily Collier (Undergraduate).

[Climate modeling using global simulations with a coupled atmosphere-ocean general circulation model
for time slices at: the Last Glacial Maximum (LGM); 16,000 before present (B.P.); 9,000 B.P.; 6,000
B.P; and today].
A comparison between the LGM and modern simulations provides an estimate of the magnitude of
climate change in particular geographical regions between glacial and interglacial states, while the late
glacial and Holocene simulations provide information on the transition between these two states. The
global simulations have been analyzed for the southern hemisphere in detail. In particular, the changes in
strength and location of the southern hemisphere jet stream and its baroclinic eddies, changes in Southern
Ocean sea ice, and changes in snow accumulation over southern South America. A MSc student, Ted
Pollock, and an undergraduate student Emily Collier (recently admitted to the PhD program at the
University of Alberta with an NSERC scholarship) configured a regional model to simulate in more detail
the climate over southern South America and much of the Southern Ocean as well as Antarctica for each
of the abovementioned simulations. The regional model is forced by data obtained from the global model
but has the advantage of much higher spatial resolution, which is important in mountainous regions such
as the Andes that generate large amounts of orographic precipitation. The outer domain of the regional
model covers southern South America and much of the Southern Ocean upstream of the lake, and the
two-way nesting capability of the model is currently being exploited to take the spatial resolution down to
a 2.5 kilometer grid through four inner domains nested within the large outer domain that is driven by the
GCM. Diagnostics of these simulations will included estimates of changes in the equilibrium line altitude
in the mountainous regions west of Lake Potrok Aike, as well as changes in precipitation over the lake
and changes in wind speed and direction over the region.

Contact info

Andrew Bush

Organisation: University of Alberta, Earth and Atmospheric Sciences, Edmonton, Canada
Research Field: General circulation model, Paleoclimate, Climate variability
Contacts: (780) 492-0351, andrew.bush@ualberta.ca