HR: 1020h
AN: PP52A-0649    [Abstracts]
TI: Using GCM Data to Reconstruct Regional Climatic Trends in Canada
AU: * Stevens, M B
EM: bstevens@stfx.ca
AF: Environmental Sciences Research Centre St Francis Xavier University, 1 West Street, Antigonish, NS B2G 2W5 Canada
AU: Gonzalez-Rouco, J F
EM: fidelgr@fis.ucm.es
AF: Dpt. Astrofisica y Ciencias de la Atmosfera, Universidad Complutense Madrid, Av. Complutense, Madrid, 28040 Spain
AU: Beltrami, H J
EM: hugo@stfx.ca
AF: Environmental Sciences Research Centre St Francis Xavier University, 1 West Street, Antigonish, NS B2G 2W5 Canada
AB: In order to distinguish anthropogenic forcing on the Earth's climatic signal from its natural variability, General Circulation Models (GCMs) are used to model surface air temperature (SAT) of the entire globe on centennial time scales. However, GCMs need to be compared with paleoclimatic data to validate their projections. Paleoclimatic records reconstructed from boreholes provide a robust view of long-term trends in SAT, and can therefore be used to validate the SAT histories modelled by GCMs. The GCM ECHO-g simulated SAT data for the past millenium, with a spatial resolution of 3.75 degrees for three runs of differing conditions: The first run, FOR1, imposes anthropogenic forcing on the natural climatic signal; FOR2 also models anthropogenic forcing, but with warmer initial conditions than FOR1; The final run is a control run, with no anthropogenic forcing. 350 boreholes from Canada were used as a record of past climate. These boreholes were grouped into 4 different geographic regions: British Columbia and Yukon; Manitoba and Saskatchewan; Quebec and Eastern Ontaio; Atlantic Canada. For each region, the average temperature perturbation was found by inverting all of the individual thermal profiles within the region. Using the regional average SAT from ECHO-g, the corresponding ``forward'' thermal profile was found, and compared with the average obtained by inversion. This procedure was applied to all three ECHO-g runs. Results show that ECHO-g SAT data is consistent with borehole data on a regional scale. That is, the integrations of ECHO-g appear to be able to simulate long-term trends in climate as recorded by the subsurface temperature for these regions in Canada.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1637 Regional climate change
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
DE: 4928 Global climate models (1626, 3337)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005