Page:Lawhead columbia 0054D 12326.pdf/207

From Wikisource
Jump to: navigation, search
This page has been proofread, but needs to be validated.


other factors) between the different systems being modeled.

A similarly named (but distinct) process called “flux adjustment” (or “flux correction”) has been traditionally employed to help correct for local (in either the temporal or spatial sense) cyclical variations in the different modeled systems, and thus help ensure that the model’s output doesn’t drift too far away from observation. Seasonal temperature flux is perhaps the most significant and easily-understood divergence for which flux adjustment can compensate. Both the atmosphere and the ocean (at least the upper layer of the ocean) warm during summer months and cool during winter months. In the region known as the interface boundary--the spatial region corresponding to the surface of the ocean, where water and atmosphere meet--both atmospheric and oceanic models generate predictions about the magnitude of this change, and thus the fluctuation in energy in the climate system. Because of the difficulties mentioned above (i.e. differences in response time between seawater and air), these two predictions can come radically uncoupled during the spring and fall when the rate of temperature change is at its largest. Left unchecked, this too can lead to the dynamics of the ocean and atmosphere “drifting” apart, magnifying the error range of predictions generated through direct couplings of the two models. Properly designed, a flux adjustment can “smooth over” these errors by compensating for the difference in response time, thus reducing drift.

6.2.2 Flux Adjustment and “Non-Physical” Modeling Assumptions

Flux adjustment was an early and frequent object of scrutiny by critics of mainstream climatology. The “smoothing over” role of the flux adjustment is frequently seized upon by critics of simulation-based climate science as unscientific or ad-hoc in a problematic way. The

197