Comparing Flux Measurements Across Scale in a Central Plains Grassland

The fluxes of energy, water, and carbon between the atmosphere and the land surface have both local and global effects on the climate system. The Eddy Covariance (EC) method is a common technique employed to quantify these fluxes. While there are hundreds of EC towers across the globe, the scale at which these towers collect data is small. Generalizations about fluxes within the broader region are, at best, difficult, given the small scale of the towers. To what extent can patch level fluxes derived from EC measurements be used to infer regional scale fluxes? This study addresses this question by using several years of co-located Large Aperture Scintillometer (LAS) flux measurements and EC tower observations at the Ameriflux tower at the Konza Prairie Long Term Ecological Research station in north-central Kansas. Given that the LAS is of the same scale as MODIS satellites, the agreement of fluxes across all three instruments can be quantified as a function of the instrument footprint and local meteorological conditions. We hypothesize that the greater the heterogeneity of soil moisture and vegetation cover over the measurement area will lead to less agreement between the EC measurement and the LAS measurement.