A Nonlinear Dynamics-Based Analysis of the Temperature Difference between the Surface Interaction and the Atmosphere as Source of Uncertainty in Chemical transport models

Abstract

Surface processes have important implications for simulations in chemical transport models. Parameterization of these processes is a source of significant uncertainty due to the following issues: (i) calculating the surface temperature and the height of the atmospheric boundary layer (ABL) and (ii) parameterization of the resistances needed to compute dry deposition over vegetated surfaces. We applied the methods of nonlinear dynamics to analyze the behavior of temperature differences between the surface and the atmosphere as a source of boundary layer uncertainty in chemical transport models. To demonstrate how canopy density affects the simulation of air temperature within the canopy and thus the evolution of ABL height, we performed experiments using the LAPS scheme coupled with a 1-D ABL model. The coupled model was run for a sunflower canopy field assuming different plant densities. Before applying the methods of nonlinear dynamics, we (i) derived a difference equation representing energy exchange across the environmental interface and reduced it to the logistic equation and (ii) considered two types of entropy as a measure of complexity. The logistic parameter determines the complexity of the turbulent energy exchange processes in the air in the vicinity of the environmental interface. The parameters of the nonlinear dynamics, i.e., the two kinds of entropy and the Lyapunov exponent, perform a similar function. Using the derived logistic equation, we analyzed its behavior and determined the possible sources of uncertainty. We offer a novel approach based on non-linear dynamics to treat the uncertainty in chemical transport models caused by the complex features of the underlying surface.