Impacts of Land Surface Heterogeneity on Atmospheric Flows during the MATERHORN Playa Field Campaign

Current weather forecast and atmospheric numerical models utilize a flux-profile similarity to characterize roughness lengths for momentum, temperature and moisture. Limited spatial and short time scales in conjunction with temporal averaging provides mean surface fluxes to predict micro and mesoscale interactions in these models. Impacts of using constant momentum and scalar roughness length scales in transient modeling of the atmospheric boundary layer (ABL) is not well understood. We present an examination of the spatiotemporal heterogeneities in the spring 2013 MATERHORN Playa field campaign during intensive observation period 9 (IOP9), which provides an interrogation region in the Salt Flats with homogeneous surface roughness. A FLIR thermal camera in conjunction with adjacent tower data allows us to present (1) a formulation of a novel analytical calculation of surface heat flux, (2) exposure of the homogeneous surface flux assumption in Monin-Obukhov similarity theory on a heterogeneous interrogation region, and (3) parametrization of the impacts of heterogeneous surface scalar fluxes on the transport of momentum and heat flux to the mesoscale features in the ABL. Implementation of the presented parameterizations on surface heterogeneity into large eddy simulation (LES) will also be discussed.