Vegetation regulation on streamflow intra-annual variability through adaption to climate variations
This study aims to provide a mechanistic explanation of the empirical patterns of streamflow
intra-annual variability revealed by watershed-scale hydrological data across the contiguous United States.
A mathematical extension of the Budyko formula with explicit account for the soil moisture storage change
is used to show that, in catchments with a strong seasonal coupling between precipitation and potential
evaporation, climate aridity has a dominant control on intra-annual streamflow variability. But in other
catchments, additional factors related to soil water storage change also have important controls on how
precipitation seasonality propagates to streamflow. More importantly, use of leaf area index as a direct and
indirect indicator of the above ground biomass and plant root system, respectively, reveals the vital role of
vegetation in regulating soil moisture storage and hence streamflow intra-annual variability under different
climate conditions.
This research was supported by the
Office of Science of the U.S. Department
of Energy as part of the Regional and
Global Climate Modeling Program and
Earth System Modeling Program. The
Pacific Northwest National Laboratory is
operated for DOE by Battelle Memorial
institute under contract DE-AC05-
76RLO 1830. The last author would like
to thank the Austrian Academy of
Sciences (project on Predictability of
runoff in a changing environment) for
financial support.