Satellite and Station Observations Demonstrate Water Availability's Effect on Continental‐Scale Evaporative and Photosynthetic Land Surface Dynamics

Abstract

Abstract Evapotranspiration and photosynthetic carbon uptake are both constrained by water availability, with presumed water‐limited and water‐independent but energy‐limited regimes. We investigate water availability's relationships with evaporative fluxes and photosynthetic measures at continental scale using surface and satellite‐based observations. The observation‐driven approach is independent of prior model‐based estimates. We find water‐limited and water‐independent regimes for both energy and carbon cycle processes in spatial and temporal aggregate, differences in water‐limitation relationships across ecohydrological regions, and more consistent signs of water limitation in photosynthetic than evaporative processes. Ecosystem water use efficiency's response to water availability changes in sign with aridity state across time and space generally but shows negative correlations in temporal anomalies.