Monday, August 19, 2013

New paper finds climate model results are 'substantially' erroneous because they assume the Earth is flat

A new paper published in Theoretical and Applied Climatology finds "substantial" differences between conventional climate models that assume the Earth is flat as compared to a model that accounts for 3-D geography over mountainous regions. The authors use topography data over the Tibetan Plateau in their 3-D model and find deviations in net solar radiation at the surface "range from −150 to 180 W/m2 over the Tibetan Plateau. The local deviation in the solar flux could lead to earlier onset of convection and more small-scale circulation." The authors "demonstrate that the entire Tibetan Plateau would receive more solar flux by about 14 W/m2, if its 3-D mountain structure was included in the calculations, which would result in larger sensible and latent heat transfer from the surface to the atmosphere." By way of comparison, 14 W/m2 is about four times greater than the IPCC alleged forcing from doubled CO2 levels. The paper's findings are ironic in light of Obama's claims that CAGW skeptics are members of the Flat Earth Society. 

Excerpts:


We show that over the Tibetan Plateau on 21 March 2001 (spring equinox), the largest deviations in the direct flux with reference to plane-parallel results are about −200 and 200 W/m2 on the shaded and sunward sides of the mountains, respectively. Over high-albedo snow-covered areas, the largest deviations in the direct-reflected- and coupled fluxes are about 200 and 40 W/m2 , respectively. Combining all five components, deviations in the net surface solar flux range from −150 to 180 W/m2 over the Tibetan Plateau. The local deviation in the solar flux could lead to earlier onset of convection and more small-scale circulation. The domain averaged deviations in surface solar fluxes over the whole Tibetan Plateau is on the order of 14 W/m2 at noon of spring equinox, in which the dominant term is the direct-reflected flux, while the contribution of other components is almost 0. This shows that the surface receives more solar energy than the results calculated from conventional 1-D models, which could lead to stronger convection and enhanced snowmelt rate. While the deviations discussed above are based on the grid size of 10×10 km2, significant deviations on the order of 20 W/m2 can be found even at a resolution of 100×100 km2. 

Finally, while the current parameterization approach has been developed for clear sky surface solar flux, it should be noted that because the direct- and direct-reflected fluxes do not encounter atmospheric multiple scattering, the regression equations for these fluxes remain unchanged in cloudy conditions. As a first approximation, the coefficients obtained for clear sky conditions can be applied directly to cloudy conditions. In mountainous areas, however, cloud issues are more complex and require further research and analysis.


Volume 113Issue 1-2pp 95-103

Impact of 3-D topography on surface radiation budget over the Tibetan Plateau


The 3-D complex topography effect on the surface solar radiative budget over the Tibetan Plateau is investigated by means of a parameterization approach on the basis of “exact” 3-D Monte Carlo photon tracing simulations, which use 90 m topography data as building blocks. Using a demonstrative grid size of 10 × 10 km2, we show that differences in downward surface solar fluxes for a clear sky without aerosols between the 3-D model and the conventional plane-parallel radiative transfer scheme are substantial, on the order of 200 W/m2 at shaded or sunward slopes. Deviations in the reflected fluxes of the direct solar beam amount to about +100 W/m2 over snow-covered areas, which would lead to an enhanced snowmelt if the 3-D topography effects had been accounted for in current climate models. We further demonstrate that the entire Tibetan Plateau would receive more solar flux by about 14 W/m2, if its 3-D mountain structure was included in the calculations, which would result in larger sensible and latent heat transfer from the surface to the atmosphere.

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1 comment:

  1. http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50720/abstract

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