The central aim of this working group is to improve understanding of the transport and exchange of momentum, mass and energy between the Earth’s surface and the atmosphere in mountainous terrain. Multiple surface types are of interest, including snow/ice, vegetation, urban areas and water bodies.
The main region of interest is the surface-layer and lower atmospheric boundary layer, although there are close links with larger-scale processes in the Mountain Boundary Layer Working Group. Topics of interest include anabatic and katabatic flow, advection, flux divergence, nocturnal jets, interaction between valley winds and slope winds, and cold-pool evolution.
The Surface-Atmosphere Exchange Working Group will play a key role in the design of the TEAMx Observational Campaign, delivering near-surface turbulence measurements across a range of sites and locations. This requires careful consideration of what the measurements represent and their uncertainties. For example, how applicable are our current measurement techniques in complex terrain? Which processes are captured by the observations and which are missed? What are the consequences of applying assumptions usually made over flat and horizontally homogeneous environments? An important task will be developing recommendations for data processing in complex terrain.
The observational data will be used to investigate a variety of topics that have, thus far, been little studied in mountainous terrain. These include, improving understanding of the processes involved in transport and exchange of momentum, heat and mass between the surface and atmosphere over mountainous terrain, investigating the processes responsible for energy balance under-closure and uncertainties in carbon dioxide uptake over mountainous terrain to enable more robust interpretation of eddy covariance fluxes and more accurate quantification of the global carbon budget, analysing the lesser-studied conditions (e.g. wintertime, snow cover) and surfaces (e.g. glaciers, urban areas, water bodies) that are important in mountain regions, studying the effect of surface and sub-surface heterogeneity (e.g. in vegetation or soil characteristics) on surface-atmosphere exchange, and generalising flux-profile scaling relations to improve surface exchange parameterisations in horizontally heterogeneous and non-flat terrain.