HR: 17:30h
AN: B42D-06    [PDF]
TI: Investigation of Relationships between Canopy Conductance, Carbon Exchange and Evapotranspiration using FLUXNET data
AU: * Falk, M
EM: mfalk@nature.berkeley.edu
AF: UC Berkeley,ESPM, 151 Hilgard Hall - MC 3110, Berkeley, CA 95616
AU: Baldocchi, D D
EM: baldocchi@nature.berkeley.edu
AF: UC Berkeley,ESPM, 151 Hilgard Hall - MC 3110, Berkeley, CA 95616
AB: Using FLUXNET data from a wide range of ecosystems, from tropical to arctic flux tower sites we investigate relationships between canopy conductance, ecosystem CO$_2$ exchange and evapotranspiration. By inverting the Penman-Monteith Equation we calculate the canopy conductance g$_s$ for the canopy seen as a big leaf. The leaf level relationship between stomatal conductance and net assimilation can be rewritten for the whole canopy as g$_s$ = a + b NEE RH$_s$/ C$_s$ where g$_s$ is the canopy conductance, NEE the half-hourly net ecosystem exchange of CO$_2$, RH$_s$ surface relative humidity and C$_s$ surface CO$_2$-concentration. We are especially interested to see whether this leaf-level relationship holds true on a canopy scale for a wide range of different canopies and ecosystems as it could be used to scale tower measurements across larger spatial scales with the aid of remote sensing products. For our calculations mid-day data were used for the whole year in evergreen and for growing season only in deciduous and crop canopies. The resulting relationships were highly linear with an average slope a = -10.45 and intercept b = 0.32 with some degree of variation for different types of ecosystems and functinal types.
DE: 0400 Biogeosciences
DE: 1704 Atmospheric sciences
SC: Biogeosciences [B]
MN: 2003 Fall Meeting