The influence of climate on vegetation physiognomy has been well documented, yet less is known about the degree to which climate affects the exchange of water, carbon, and energy between vegetation and the atmosphere, a potential feedback mechanism that must be better understood if we are to develop an integrated model of the way in which vegetation and climate dynamically interact. Diurnal patterns of carbon dioxide flux at locations along the Kalahari Transect, southern Africa. Uptake by vegetation results in a negative daytime flux, while respiration dominates during the night. Mean annual precipitation decreases in a north-south direction. Botswana for several days at each site.
Bars represent the standard deviation of the hourly binned values.
All sites display the expected decrease in WUE with increasing VPD, although the individual relationships are stratified according to the position of the sites along the long-term aridity gradient. For example Mongu, which has the wettest climate, has a much lower WUE for like levels of D than Tshane, which historically has the most arid climate. My research in this area focuses on techniques for defining the processes of water and carbon dioxide exchange between a forest and the atmosphere. Coherent turbulent structures associated with transport events can be identified and conditionally analyzed from the time series by the wavelet analysis, which retain information in time domain as well as the frequency domain. CO2 wavelet coefficients for a 30-min. time series.