Turbulent flux modelling with a simple 2-layer soil model and extrapolated surface temperature applied at Nam Co Lake basin on the Tibetan Plateau
- 1Centre for Atmospheric Science, Department of Geography, University of Cambridge, UK
- 2Department of Micrometeorology, University of Bayreuth, Germany
- 3Department of Geography, University of Cambridge, UK
- 4Cold and Arid Region Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China
- 5Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
- 6Member of Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Germany
Abstract. This paper introduces a surface model with two soil-layers for use in a high-resolution circulation model that has been modified with an extrapolated surface temperature, to be used for the calculation of turbulent fluxes. A quadratic temperature profile based on the layer mean and base temperature is assumed in each layer and extended to the surface. The model is tested at two sites on the Tibetan Plateau near Nam Co Lake during four days during the 2009 Monsoon season. In comparison to a two-layer model without explicit surface temperature estimate, there is a greatly reduced delay in diurnal flux cycles and the modelled surface temperature is much closer to observations. Comparison with a SVAT model and eddy covariance measurements shows an overall reasonable model performance based on RMSD and cross correlation comparisons between the modified and original model. A potential limitation of the model is the need for careful initialisation of the initial soil temperature profile, that requires field measurements. We show that the modified model is capable of reproducing fluxes of similar magnitudes and dynamics when compared to more complex methods chosen as a reference.