Stable Atmospheric Boundary Layers and Diurnal Cycles: Challenges for Weather and Climate Models

Abstract

The representation of the atmospheric boundary layer is an important part of weather and climate models and impacts many applications such as air quality and wind energy. Over the years, the performance in modeling 2-m temperature and 10-m wind speed has improved but errors are still significant. This is in particular the case under clear skies and low wind speed conditions at night as well as during winter in stably stratified conditions over land and ice. In this paper, the authors review these issues and provide an overview of the current understanding and model performance. Results from weather forecast and climate models are used to illustrate the state of the art as well as findings and recommendations from three intercomparison studies held within the Global Energy and Water Exchanges (GEWEX) Atmospheric Boundary Layer Study (GABLS). Within GABLS, the focus has been on the examination of the representation of the stable boundary layer and the diurnal cycle over land in clear-sky conditions. For this purpose, single-column versions of weather and climate models have been compared with observations, research models, and large-eddy simulations. The intercomparison cases are based on observations taken in the Arctic, Kansas, and Cabauw in the Netherlands. From these studies, we find that even for the noncloudy boundary layer important parameterization challenges remain.

Using MODIS land surface temperatures and the Crocus snow model to understand the warm bias of ERA-Interim reanalyses at the surface in Antarctica

“…This is treated differently in IFS, which could explain the warm bias. Holtslag et al (2013) show that T 2 m forecasted in winter over snow-covered areas with IFS is much more sensitive to slight changes in the stability functions with the current version of IFS than they were in previous versions. In order to demonstrate the sensitivity of T s to air temperature and to the representation of surface turbulent fluxes, four numerical experiments were made with Crocus under the following configurations: three experiments with a constant change in ERA-Interim T 2 m of +2, −2 and −4 • C, respectively, and an additional experiment with a change in ERA-Interim T 2 m of −4 • C and a change in the maximum Richardson number from its original 0.2 value to 0.1, which enhances the turbulent fluxes towards the surface in very stable conditions.…”

“…The difficulty of properly estimating the surface turbulent fluxes under very stable conditions has been extensively documented (for example Brun et al (1997), Martin and Lejeune (1998), Essery and Etchevers (2004), Anderson and Neff (2008), Sukoriansky et al (2006), Town and Walden (2009), Genthon et al (2010), Holtslag et al (2013)). Ad hoc treatments are often introduced in meteorological and snow models to solve the problem, as was done in SURFEX/Crocus with the introduction of the limitation in the Richardson number.…”

Impacts of aerosol-radiation feedback on local air quality during a severe haze episode in Nanjing megacity, eastern China

“…Because NO 2 mixing ratio is influenced by local effects, such as emission and diffusion, the model overestimation of NO 2 in this study may be caused by the uncertainties in emission inventory and boundary layer conditions. The underestimation of O 3 peaks, particularly on clean days before 14 October, might be because of the model inability to accurately represent the stable boundary layer (Holtslag et al, 2013), the overestimation of titration loss near the source regions (Im et al, 2015), and the model errors in temperature fields (Fig. 2).…”

Wavelike Structures in the Turbulent Layer During the Morning Development of Convection at Dome C, Antarctica

“…It is now generally recognized that peculiarities of the stable ABL, including wave activity, affect not only regional weather, but also the general circulation of the atmosphere (see, e.g. Zilitinkevich and Esau 2003;Esau and Zilitinkevich 2010;Holtslag et al 2013;McGrath-Spangler et al 2015). A poor understanding of the exchange processes in the stable ABL and difficulties in its parametrization inhibit the development of numerical modelling of regional and local weather (Mahrt 1998;Cohen et al 2015).…”