TRACE GAS-EXCHANGE OVER TERRESTRIAL ECOSYSTEMS - METHODS AND PERSPECTIVES IN MICROMETEOROLOGY

Quantification of the surface-atmosphere exchange of trace gases is re cognized as an essential prerequisite to understanding the role of the biosphere in the global climate system. Among the micrometeorological methods available to measure surface-atmosphere fluxes, the aerodynam ic gradient, the energy balance/Bowen ratio, the eddy covariance and t he eddy accumulation methods are the most widely employed. This brief review describes the theoretical background and the practical applicat ions of these methodologies and is particularly directed to plant ecop hysiologists, ecologists and botanists who may be interested in scalin g biological processes to the canopy level.