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Climate Baseline Scenarios and GCMs performance By Mario Bidegain (Facultad de Ciencias – UR LA32/LA26) Ines Camilloni (Facultad de Ciencias – UBA LA26) AIACC Latin America/Caribbean Regional Workshop 26-29 May 2003, San Jose, Costa Rica. OUTLINE. What are GCMs?
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Climate Baseline Scenarios and GCMs performance By Mario Bidegain (Facultad de Ciencias – UR LA32/LA26) Ines Camilloni (Facultad de Ciencias – UBA LA26) AIACC Latin America/Caribbean Regional Workshop 26-29 May 2003, San Jose, Costa Rica
OUTLINE • What are GCMs? • What GCMs outputs were selected from IPCC DDC? 3. What variables were selected for this study? 4. Preliminary conclusions for southeastern South America
Growth in population, energy demand, changes in technological and land/cover Energy-economy models Greenhouse gases emissions Carbon cycle and other and other chemical models Atmospheric GHGs concentrations Climate models Baseline and future climate projections What are GCMs? What they do? Simulate the response of the global climate system to increasing greenhouse gas concentrations.
What are GCMs? What they work? GCMs are based on the known laws of physics describing the transport of mass and energy, depicting the global climate using a three dimensional grid over the globe.
What GCM outputs were selected from IPCC DDC? SRES A2 forced runs: CCCMA, CSIRO, GFDL, HadCM3, NCAR-PCM
Region selected for this study Southeastern Southamerica: 20° to 47° South 45° to 67° West
What variables were selected for this study? ü Sea level pressure (as indicator of goodness of GCMs to reproduce the general circulation in the region) Rainfall (mean monthly and annual values) and annual cycle) ü Temperature (monthly mean and annual values) ü
Spatial Correlation for Sea Level Pressure between GCMs outputs and NCEP reanalysis
Sea Level Pressure anomalies: GCMs vs.NCEP reanalysis CSIRO-NCEP (1961-2000) HADCM3-NCEP (1950-2000) NCEP (1950-2000) ECHAM4-NCEP (1990-2000)
What climate baseline scenario for rainfall the GCMs estimate?
GCMsrainfall anomalies (mm/day) HADCM3 (1950-99) CSIRO (1961-99) ECHAM4 (1991-99)
What climate baseline scenario for temperature the GCMs estimate?
Precipitation and Temperature Changes Argentina 9 GCMs (2070-99 vs. 1961-90)
PRELIMINARY CONCLUSIONS General Conclusion • Very good performance of GCMs in temperature and SLP, poor to fair in rainfall (underestimation in the region), but improved performance respect to old GCMs versions Future actions • 3 GCMs will be selected to construct climate scenarios (HADLEY, ECHAM and CSIRO. • The selected variables will be: SLP (to estimate surface winds), precipitation and temperature. • Statistical and/or dynamical downscalling, for selected locations, will be applied to future climate scenarios.