The need for micrometeorological research of the response of the energy balance of vegetated surfaces to CO2 enrichment

A Penman-Monteith equation has been used to evaluate a change in canopy resistance on the evapotranspiration of a savannah and agricultural area in Botswana. After a short introduction, some problems concerning the K-theory or first order closure are indicated when one uses it for transport modelling within and above a canopy. The Penman-Monteith equation was used to calculate the canopy resistance for a savannah vegetation and sorghum under the same environmental conditions. After that, by changing the stomatal resistance due to an increase of the CO₂ content, the change in the evapotranspiration was estimated.Finally some recommendations for future research are given and an outline of a proposed FACE experiment is presented.