Abstract
Abstract. The roughness sublayer (RSL) is one compartment of the surface layer (SL) where turbulence deviates from Monin–Obukhov similarity theory. As the computing power increases, model grid sizes approach the gray zone of turbulence in the energy-containing range and the lowest model layer is located within the RSL. From this perspective, the RSL has an important implication in atmospheric modeling research. However, it has not been explicitly simulated in atmospheric mesoscale models. This study incorporates the RSL model proposed by Harman and Finnigan (2007, 2008) into the Jiménez et al. (2012) SL scheme. A high-resolution simulation performed with the Weather Research and Forecasting model (WRF) illustrates the impacts of the RSL parameterization on the wind, air temperature, and rainfall simulation in the atmospheric boundary layer. As the roughness parameters vary with the atmospheric stability and vegetative phenology in the RSL model, our RSL implementation reproduces the observed surface wind, particularly over tall canopies in the winter season by reducing the root mean square error (RMSE) from 3.1 to 1.8 m s−1. Moreover, the improvement is relevant to air temperature (from 2.74 to 2.67 K of RMSE) and precipitation (from 140 to 135 mm per month of RMSE). Our findings suggest that the RSL must be properly considered both for better weather and climate simulations and for the application of wind energy and atmospheric dispersion.
Highlights
The planetary boundary layer (PBL) is important for the proper simulation of weather, climate, wind energy application, and air pollution
Our findings suggest that a small LAI in the winter season makes a larger Lc bewww.geosci-model-dev.net/13/521/2020/
Monin–Obukhov similarity theory (MOST) can be only applicable in the inertial layer and turbulence deviates from MOST in the roughness sublayer
Summary
The planetary boundary layer (PBL) is important for the proper simulation of weather, climate, wind energy application, and air pollution. The RSL function of the HFs is based on a theoretical background and applicable to a wide range of atmospheric stabilities by succinctly satisfying the continuity of the vertical profiles of fluxes, wind, and scalars both at the top of the RSL and at the top of a canopy. Based on the abovementioned background, this study incorporates the RSL parameterization based on the RSL function of the HFs into the WRF model (version 3.7.1). For this purpose, we reformulate the HFs’ RSL parameterization to implement it in the SL parameterization in the WRF model and discuss the impacts of the RSL parameterization on the regional weather and climate simulations in terms of meteorological conditions near the Earth’s surface.
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