1State Key Laboratory of Soil Erosion and Dryland
Farming on the Loess Plateau, Institute of Soil and Water Conservation, CAS
& MWR, Yangling, Shaanxi 712100, China
2University of the Chinese Academy of Sciences, Beijing
3College of Natural Resources and Environment,
Northwest A&F University, Yangling, Shaanxi 712100, China
Received: 14 Sep 2016 – Discussion started: 17 Oct 2016
Abstract. Within the Budyko framework, the controlling parameter (ω in the Fu equation) is widely considered to represent landscape conditions in terms of vegetation coverage (M); however, some qualitative studies have concluded that climate seasonality (S) should be incorporated in ω. Here, we discuss the relationship between ω, M, and S, and further develop an empirical equation so that the contributions from M to actual annual evapotranspiration (ET) can be determined more accurately. Taking 13 catchments in the Loess Plateau as examples, ω was found to be well correlated with M and S. The developed empirical formula for ω calculations at the annual scale performed well for estimating ET by the cross-validation approach. By combining the Budyko framework with the semi-empirical formula, the contributions of changes in ω to ET variations were further decomposed as those of M and S. Results showed that the contributions of S to ET changes ranged from 0.1 to 74.8 % (absolute values). Therefore, the impacts of climate seasonality on ET cannot be ignored, otherwise the contribution of M to ET changes will be estimated with a large error. The developed empirical formula between ω, M, and S provides an effective method to separate the contributions of M and S to ET changes.
Revised: 18 Jan 2017 – Accepted: 07 Feb 2017 – Published: 10 Mar 2017
Ning, T., Li, Z., and Liu, W.: Vegetation dynamics and climate seasonality jointly control the interannual catchment water balance in the Loess Plateau under the Budyko framework, Hydrol. Earth Syst. Sci., 21, 1515-1526, doi:10.5194/hess-21-1515-2017, 2017.