TWC-Matthew McCabe

UNSW Water Research Centre

Local to global scale estimation of evapotranspiration: resolving inconsistencies and evaluating estimates from multi-scale retrievals

Accurate estimation of surface heat fluxes is of considerable interest to meteorological, climatological and agricultural investigations as they identify the key physical processes that link the land surface with the atmosphere. While characterising surface fluxes is critical in describing the partitioning of water and energy across Earths terrestrial surfaces, accurately monitoring the spatial variation, particularly at daily and sub-daily scales, is notoriously difficult. Spatial and temporal scaling issues, errors in forcing variables, heterogeneity in surface characteristics and simplifications in process understanding, all limit the capacity to accurately monitor flux development and variability.

In this presentation, common approaches such as the Penman-Monteith formulation are considered alongside surface energy balance retrievals and coupled regional climate model output to examine the variation and consistency within these different estimation approaches. The work is discussed in the context of an international collaborative effort to develop a global observationally based climatology of surface heat fluxes, which is being coordinated by the GEWEX Radiation Panel. The talk will also detail work being undertaken to construct Australia’s first comprehensive hydrological observatory: an effort that will prove useful in the evaluation of remote sensing retrievals and coupled (and uncoupled) hydrological models.