Modeling the Evolution of the Atmospheric Boundary Layer Coupled to the Land Surface for Three Contrasting Nights in CASES-99

Abstract

The modeling and prediction of the stable boundary layer over land is a persistent problematic feature in weather, climate and air quality topics. Here, the performance of a state-of-the-art single column boundary-layer model is evaluated with observations from the CASES-99 field experiment. Very high model resolution in the atmosphere and the soil is utilized to represent three different stable boundary-layer archetypes, namely: a fully turbulent night, an intermittently turbulent night and a radiative night with hardly any turbulence (all at clear skies). Each archetype represents a different class of atmospheric stability. In the current model, the atmosphere is fully coupled to a vegetation layer and the underlying soil. In addition, stability functions (local scaling) are utilized based on local observations. Overall it is found that the vertical structure, the surface fluxes (apart from the intermittent character) and the surface temperature in the stable boundary layer can be satisfactorily modeled for a broad stability range (at a local scale) with our current understanding of the physics of the stable boundary layer. This can also be achieved by the use of a rather detailed coupling between the atmosphere and the underlying soil and vegetation, together with high resolution in both the atmosphere and the soil. This is especially true for the very stable nights, where longwave radiative cooling is dominant. Both model outcome and observations show that in the latter case the soil heat flux is a dominant term of the surface energy budget.3

Evaluation of the Diurnal Cycle in the Atmospheric Boundary Layer Over Land as Represented by a Variety of Single-Column Models: The Second GABLS Experiment

“…Two consecutive clear days from the CASES-99 data, which indicated a strong diurnal cycle over relatively dry land, were selected for the intercomparison study. It is noted that Steeneveld et al (2006) performed a case study with these data and found good agreement with their model set-up that allowed for surface feedback and radiation processes in addition to turbulence. In the present study, we focus on the intercomparison of boundary-layer schemes, and so the forcing conditions have been simplified to facilitate a straightforward comparison between the model closures rather than detailed comparison with observations.…”

Local scaling characteristics of Antarctic surface layer turbulence

“…In the recent past, in the absence of a formal (universally accepted) theory of SBL, local scaling-based results have quite frequently served as benchmarks for new-generation stably stratified turbulence modeling approaches (for an example see ). Local scaling is also an integral part of numerous local closure-based present-day atmospheric models (e.g., Steeneveld et al, 2006;Brown et al, 2008). Lastly, it has established its niche in the applied field of dispersion modeling (Scire et al, 2000).…”

Improving the WRF model's (version 3.6.1) simulation over sea ice surface through coupling with a complex thermodynamic sea ice model (HIGHTSI)

“…The Arctic cloud, particularly the mixed-phase low cloud, is misrepresented in current state-of-the-art climate models (Pithan et al, 2013;English et al, 2015). Simulating the stable boundary layer is limited not only by the relatively coarse resolution (Steeneveld et al, 2006), but also by the lack of realistic representations of small-scale physical processes, such as turbulent mixing and snow-surface coupling (Sterk et al, 2013). As a result, considerable effort has been devoted to evaluating and improving the microphysics and boundary layer parameterizations (e.g., Wang and Liu, 2014;Andreas et al, 2010).…”