Water and carbon flux responses to soil moisture pulses in the Western United States

Abstract

In this study, the relationships among plant water and carbon flux responses to soil moisture resource pulses in semi-arid lands of the Western United States were diagnosed. Measurements from twelve AmeriFlux tower (in situ) and SMAP (satellite) sites across the region were used to estimate relationships between carbon flux and resource availability. The differences between respiration and photosynthesis dominant regimes and the transition from water to energy limited regimes could be observed. Water use efficiency of plants in the regions was estimated to be around 5.0 grams of carbon dioxide per 1 kilograms of water when water was excess. Response patterns were shared among the similar ecosystems. The role of water and carbon flux response to intermittency resource availability could lead to improved estimation of land carbon budgets.