Date: 8 – 10 November 2016
Location: Vrije Universiteit (VU) Amsterdam, The Netherlands
Who: Scientists interested in thermodynamic optimality principles applied to land-surface atmosphere interactions and hydrological processes.
Maximum number of participants: 20
Contact person: Martijn Westhoff
The combined use of the first and second laws of thermodynamics (conservation of energy and the entropy balance) leads to physical limits or constraints to fluxes of mass and energy. A well-known limit is the Carnot limit stating that the theoretical maximum amount of work that can be subtracted from a heat engine (two connected reservoirs with a clear temperature difference) is by definition less than the energy put into the system.
It appears that the atmosphere operates close to these limits. For example: vertical turbulent heat fluxes (sensible and latent heat) could be predicted by maximizing the rate of work needed to lift the air from the (warm) surface to the (cold) atmospheric boundary layer with only solar radiation and surface temperature as input. The lifting of the air particles is caused by the temperature difference between the surface and boundary layer, while at the same time the temperature difference decreases due to the vertical transport of air. This temperature difference is even further decreased when evaporation increases. These feedbacks form the basis to obtain a maximum in work.
There is high potential to apply these principles to less idealized cases, or to vegetation or hydrological systems. Several successful attempts have been made by applying these principles to e.g. predict net primary production of trees, to predict macropore density in the unsaturated zone enhancing infiltration or to predict surface and subsurface drainage characteristics. However, these studies all use different objective functions which were optimized, while terminology, perceptions and methodology are still not uniform and clear.
This workshop aims to bring a small group of scientists together who are working in this subfield. The aim is to come to a better understanding of thermodynamic optimality principles and to share ideas and develop combined research ideas. The main focus will be on the land-surface atmosphere interactions and hydrological processes.