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Climate Models. Current Weather Great Global Warming Swindle Debunked General Circulation Models (GCMs) Changes in GCMs since 1970s Problems with GCMs Charles Rodda Presentation For Next Class: Read Ch. 12 (pp. 380-397). Debunking Great Global Warming Swindle.
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Climate Models • Current Weather • Great Global Warming Swindle Debunked • General Circulation Models (GCMs) • Changes in GCMs since 1970s • Problems with GCMs • Charles Rodda Presentation For Next Class: Read Ch. 12 (pp. 380-397)
Debunking Great Global Warming Swindle • http://www.youtube.com/watch?v=pxw3_XBvm94
General Circulation Models • Mathematical representations of the climate system, expressed as computer codes and run on powerful computers • Operate in 3-D and have capacity to represent spatial distribution of land, water, ice, elevation of mountains, vertical distribution of greenhouse gases, and changes in solar radiation • Operation of GCMs incorporates physical laws and equations that govern the circulation of Earth’s atmosphere
General Circulation Model Figure 10.33
Huge improvements in model resolution since FAR!
. . . and in modeling the physical processes!
How Reliable are GCMs? • “One source of confidence comes from the fact that model fundamentals are based on established physical laws . . . • Second source of confidence comes from the ability of models to simulate (more or less!) important aspects of the current climate” (IPCC AR4)
Limitations of GCMs • A model is a hypothesis about how the climate system operates! • Only the dynamic core of the models represent basic physics. All other components of these models are parameterizations, which means they are not fundamental physics but engineering code with tunable parameters. From Pielke (2011)
It is very difficult to accurately parameterize clouds and cloud microphysical processes in weather or climate models!