Thursday 08 Feb 2018: Forest canopy - boundary layer flows over heterogeneous terrain
Prof. Andrew Ross - University of Leeds
In recent years there has been significant interest in airflow within and above forests for a variety of applications, including understanding and interpreting flux measurements over forests, windthrow damage to trees, dispersion of seeds and impacts on wind energy. Much of the theoretical and modelling to date has focussed on two canonical problems: flow over a small hill with uniform homogeneous canopy cover and flow across the edge of a uniform forest on flat terrain. In this talk I will first present some theoretical and modelling work to look at the case of partially forested hills where both of these features are present. This allows us to begin to understand the interaction between topography and heterogeneous canopy cover in controlling boundary layer flow. I will then present some field observations from a site where neither the topography nor the forest cover is simple in order to see how these idealised conceptual models can be applied to interpret real world complexity. Finally, I will briefly discuss some of the impacts of this work on the parametrisation of the land surface and drag in weather and climate models, and the role these canopy flows play in controlling the transport of CO2 and other scalars into and out of forests.