Eddy Covariance Measurements of the Surface Energy Budget and CO2 Fluxes along the Columbia River Corridor

Land-surface fluxes and the surface energy budget are influenced by subsurface processes. Soil moisture variability is a critical driver of soil biogeochemical and plant physiological processes, affecting the partitioning of the surface energy balance and variability in trace gas fluxes. However, it remains unclear how groundwater-surface water exchange affects the availability of soil water, solutes, and nutrients which, in turn, influence land-surface fluxes. To quantify the impacts of ground water-surface water interaction on land atmosphere exchange, we examined eddy covariance data from three different ecosystems along the Columbia River, ranging from upland shrub-steppe to riparian. We characterize differences in the surface energy budget and CO₂ fluxes among the three ecosystems. In addition, we analyze how soil water availability affects the partitioning of the surface energy budget, and how this varies among the three ecosystems. We also investigate how land-surface fluxes in upland and riparian ecosystems respond differently to changes in atmospheric drivers.