An Evaluation of Land-Surface Heterogeneity Effects on Atmospheric Boundary Layer Processes at Various Scales
Abstract
Land-surface heterogeneity (LSH) at different scales has significant influence on atmospheric boundary layer (ABL) buoyant and shear turbulence generation and transfers of water, carbon and heat. The extent of proliferation of this influence into larger-scale circulations and atmospheric structures is a topic continually investigated in experimental and numerical studies, in many cases with the hopes of improving land-atmosphere parameterizations for modeling purposes. The blending height is a potential measure for the vertical propagation of LSH effects into the ABL, and has been the subject of study for several decades. Its potential as a powerful metric and the lack of combined efforts of modeling and observations are the motivations for this study. The central goal of this project is to assess how blending height estimates compare with observed and modeled vertical propagation of heterogeneity. To accomplish this, a Helicopter Observation Platform (HOP) will provide in-situ atmospheric observations at a range of different altitudes, especially in the lower ABL, where the effects of LSH are expected to be the strongest. Empirical Mode Decomposition (EMD) will be used to filter noise and unwanted trends from the HOP data and to assess possible LSH correlations. An Ocean-Land-Atmosphere-Model (OLAM), a state-of-the-art numerical model will provide high horizontal resolution mesh refinement to resolve large-eddy scale turbulence throughout the observation area. And the modeling and observations are linked through the Cloud and Land Surface Interaction Campaign (CLASIC) field campaign sites, which supply a host of additional data as well as sites with varying LSH regimes. The patchwork of different crops at the Central Facility (CF) provides a relatively small LSH scale, the forest site at Okmulgee (FS) has vegetated, bare and water areas aggregated at a larger LSH scale, and the Fort Cobb watershed (FC) is dominated by the Fort Cobb Lake, giving the largest scale of LSH. HOP observations of scalar and scalar flux profiles in the ABL, along with spectral and cospectral scaling, will be assessed at different sites in order to determine the influence of LSH scales in different atmospheric conditions, and to evaluate theoretical blending height estimates.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.A13B0209B
- Keywords:
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- 3322 ATMOSPHERIC PROCESSES / Land/atmosphere interactions