HESSD Hydrology and Earth System Sciences Discussions HESSD Hydrol. Earth Syst. Sci. Discuss. 1812-2116 Göttingen, Germany 10.5194/hessd-11-11183-2014 Do changes in climate or vegetation regulate evapotranspiration and streamflow trends in water-limited basins? Liu Q. 1 2 Yang Z. 1 2 Liang L. 3 Nan W. 1 2 Key Laboratory for Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, China State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China 09 10 2014 11 10 11183 11202 Copyright: © 2014 Q. Liu et al. 2014 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://hess.copernicus.org/preprints/11/11183/2014/hessd-11-11183-2014.html The full text article is available as a PDF file from https://hess.copernicus.org/preprints/11/11183/2014/hessd-11-11183-2014.pdf

Interactions between climate change, vegetation, and soil regulate hydrological processes. In this study, it was assumed that vegetation type and extent remained fixed and unchanged throughout the study period, while the effective rooting depth (<i>Z</i><sub>e</sub>) changed under climate change scenarios. Budyko's hydrological model was used to explore the impact of climate change and vegetation on evapotranspiration (<i>E</i>) and streamflow (<i>Q</i>) on the static vegetation rooting depth and the dynamic vegetation rooting depth. Results showed that both precipitation (<i>P</i>) and potential evapotranspiration (<i>E</i><sub>p</sub>) exhibited negative trends, which resulted in decreasing trends for dynamic <i>Z</i><sub>e</sub> scenarios. Combined with climatic change, decreasing trends in <i>Z</i><sub>e</sub> altered the partitioning of <i>P</i> into <i>E</i> and <i>Q</i>. For dynamic scenarios, total <i>E</i> and <i>Q</i> were predicted to be −1.73 and 28.22%, respectively, greater than static scenarios. Although climate change regulated changes in <i>E</i> and <i>Q</i>, the response of <i>Z</i><sub>e</sub> to climate change had a greater overall contribution to changes in hydrological processes. Results from this study suggest that with the exception of vegetation type and extent, <i>Z</i><sub>e</sub> scenarios were able to alter water balances, which in itself should help to regulate climate change impacts on water resources.

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