Thursday, October 30, 2008

Journal Club MTG5: Urban Parameterization for CCSM Part II

The paper this week is "An Urban Parameterization for the Global Climate Model. Part II: Sensitivity to Input Parameters and the Simulated Urban Heat Island in Offline Simulations" by Oleson et al. The paper builds on the previous paper and looks at the sensitivity to changing parameters within the model. The split the parameter types in 3 categories, morphological, radiance and thermal. Each category was combined using every possible combination within its own category. The results of this highlight that previous surfaces, or the lack thereof, greatly influence the latent heat available and the sensible heat is very sensitive to both the morphological and radiance parameters. The paper moves on to simulating heat islands and compared this is Oke(1981) who derived a logarithmic equation based on measurements of heat islands in US and European cities. The model simulates the increased diurnal cycle and temperature difference between urban and rural environments. The sensitivity studies also real that parameter uncertainty mainly effects the amplitude of the diurnal cycle and not the phase. Overall the paper has a few confusing parts and many graphs that could be simplified or removed, but I felt this study did a much better job than some sensitivity studies of other areas in the past.

No comments: