A three-dimensional control volume analysis of the surface energy balance

Abstract:

The closure of the surface energy balance (SEB) has been an outstanding issue in the boundary-layer community. While most SEB analyses are based on a one-dimensional control volume, this may be insufficient for situations where heterogeneity and advection are important. Herein, we present a full three-dimensional control volume analysis of the temperature-tendency equation with data collected during the IPAQS (Idealized horizontal Planar Array experiment for Quantifying Surface heterogeneity) field experiment. Data collection took place at the U.S. Army Dugway Proving grounds at the SLTEST facility, which is characterized by a long flat fetch with uniform surface roughness and strong surface thermal heterogeneity. Integration over a 3-D control volume (dimensions 400 m x 400 m x 2 m) demonstrates that during the afternoon convective period, closure of the complete three-dimensional SEB is bounded between 0 and 5%. This approach improves upon the previous one-dimensional SEB approach where residuals during the convective afternoon period are approximately 25%. Furthermore, the SEB residual is presented as a function of the non-dimensional heterogeneity parameter developed by Margairaz et al. (2020).