A Budyko-based framework for quantifying the impacts of aridity index and other factors on annual runoff

[摘要] Discerning the reasons for the changes in runoff is a key issue for understanding hydrological cycles under nonstationary conditions. This study conducted a Budyko-based framework for quantifying the impacts of aridity index and other factors on annual runoff in 355 catchments in the United States. The aridity index is the ratio of potential evapotranspiration to precipitation, representing the dry conditions in Budyko framework. Other factors are the influence of everything else except the aridity index, and are represented by the parameter w in Budyko-type equations, which is a time-dependent variable in this case. Then, the impacts of aridity index and other factors were decomposed based on the annual variations in the Budyko spaces. The results show the current Budyko-type equations, which use time-varying parameters, can improve the fitting capability for most catchments in the United States. Aridity index is the main driver causing the increasing trend of runoff in the US. Other factors, on the other hand, are the main reasons for the decreasing trend of runoff in the US.

[发布日期] 2019-12-01

[关键词] Climate change;Human activities;Runoff;Budyko equations