Environmental controls on CO2 flux variability across spatial and temporal scales

Abstract:

This presentation will bring together a series of studies that have probed the relationships between environmental drivers and CO2 flux at spatial scales ranging from the plot scale to the global scale, and time scales ranging from hourly to interannual. CO2 flux measurements from eddy covariance towers enable the examination of the primary drivers of flux variability at the plot scale, and across a range of temporal scales. Atmospheric inverse modeling studies that couple atmospheric CO2 observations with atmospheric transport models, on the other hand, make it possible to examine regional to global domains at spatial resolutions on the order of 100s of kilometers, and at hourly to monthly temporal resolutions. Taken together, the results of these studies indicate that the environmental drivers that best explain flux variability differ substantially with spatial and temporal scale. This result implies that such scale-effects need to be explicitly considered in scaling up understanding of the processes controlling flux variability. This indicates, in turn, that extreme care must be taken in scaling up process parameterizations within terrestrial biosphere models (TBMs), which are often parameterized, evaluated, and validated using plot-scale data. Such scaling is necessary in order to apply TBMs to reliably predict flux variability at regional to global, and at seasonal to interannual, scales.