Start
April 18, 2022 - 3:00 pm
End
April 18, 2022 - 4:00 pm
Boundary Layer, Urban Meteorology, and Land-Surface Processes
The impact of surface heterogeneity on surface flux estimation in stable boundary layers using single column modeling
Dominic Candela
Monday, April 18
03:00 PM
Join Google Meet
The earth’s surface is naturally heterogenous resulting in varying distributions of surface temperature, surface moisture, and aerodynamic roughness. The contrast in heterogeneities is important in determining momentum and heat transport between the surface and atmosphere. This is further complicated under stable conditions where turbulence cannot be relied on to mix out the impact of heterogeneities.
The impact of surface heterogeneity is investigated using single column modeling (SCM) to understand how well surface fluxes of heat and momentum are represented in simulations of the heterogenous stable boundary layer. The OU-NSSL SCM uses first-order and 1.5-order planetary boundary layer (PBL) turbulence closures, as well as various surface flux schemes that account for surface heterogeneity (bulk model, tile model, modified tile model) to understand how different combinations of models represent the heterogenous stable boundary layer. The SCM is validated against three different test cases: the GABLS1 LES intercomparison study, the GABLS2 SCM/LES intercomparison study, and the Boundary Layer Integrated Sensing and Simulation Field Universalization Laboratory (BLISS-FUL) deployment during summer 2021. The surface fluxes and boundary layer variables are compared to a suite of LES simulations for various surface temperature heterogeneity and aerodynamic roughness distributions for an idealized nine-hour simulation (GABLS1), and for a more complex scenario composed of a full diurnal cycle (GABLS2). Unique to BLISS-FUL, the SCM is initialized using advanced boundary layer profiling systems including uncrewed aircraft system (UAS). Results show that both the choice of the turbulence scheme and surface scheme play an important role in reproducing the LES results. Specifically, the use of higher-order PBL schemes (1.5-order) and surface flux schemes that account for land heterogeneity (tile model) give the best agreement between the SCM and LES.