气候变化领域集成服务门户(CCPortal): Seasonal partitioning of precipitation between streamflow and evapotranspiration; inferred from end-member splitting analysis

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DOI	10.5194/hess-24-17-2020
	Seasonal partitioning of precipitation between streamflow and evapotranspiration; inferred from end-member splitting analysis
	W. Kirchner J.; T. Allen S.
发表日期	2020
ISSN	1027-5606
起始页码	17
结束页码	39
卷号	24 期号:1
英文摘要	The terrestrial water cycle partitions precipitation between its two ultimate fates: "green water" that is evaporated or transpired back to the atmosphere, and "blue water" that is discharged to stream channels. Measuring this partitioning is difficult, particularly on seasonal timescales. End-member mixing analysis has been widely used to quantify streamflow as a mixture of isotopically distinct sources, but knowing where streamwater comes from is not the same as knowing where precipitation goes, and this latter question is the one we seek to answer. Here we introduce "end-member splitting analysis", which uses isotopic tracers and water flux measurements to quantify how isotopically distinct inputs (such as summer vs. winter precipitation) are partitioned into different ultimate outputs (such as evapotranspiration and summer vs. winter streamflow). End-member splitting analysis has modest data requirements and can potentially be applied in many different catchment settings. We illustrate this data-driven, model-independent approach with publicly available biweekly isotope time series from Hubbard Brook Watershed 3. A marked seasonal shift in isotopic composition allows us to distinguish rainy-season (April-November) and snowy-season (December-March) precipitation and to trace their respective fates. End-member splitting shows that about one-sixth (18±2 %) of rainy-season precipitation is discharged during the snowy season, but this accounts for over half (60±9 %) of snowy-season streamflow. By contrast, most (55± 13 %) snowy-season precipitation becomes streamflow during the rainy season, where it accounts for 38±9 % of rainy-season streamflow. Our analysis thus shows that significant fractions of each season's streamflow originated as the other season's precipitation, implying significant inter-seasonal water storage within the catchment as both groundwater and snowpack. End-member splitting can also quantify how much of each season's precipitation is eventually evapotranspired. At Watershed 3, we find that only about half (44±8 %) of rainy-season precipitation evapotranspires, but almost all (85±15 %) evapotranspiration originates as rainy-season precipitation, implying that there is relatively little inter-seasonal water storage supplying evapotranspiration. We show how results from this new technique can be combined with young water fractions (calculated from seasonal isotope cycles in precipitation and streamflow) and new water fractions (calculated from correlations between precipitation and streamflow isotope fluctuations) to infer how precipitation is partitioned on multiple timescales. This proof-of-concept study demonstrates that end-member mixing and splitting yield different, but complementary, insights into catchment-scale partitioning of precipitation into blue water and green water. It could thus help in gauging the vulnerability of both water resources and terrestrial ecosystems to changes in seasonal precipitation. © 2020. This work is distributed under the Creative Commons Attribution 4.0 License.
语种	英语
scopus关键词	Catchments; Digital storage; Evapotranspiration; Groundwater; Isotopes; Mixing; Runoff; Water supply; Watersheds; End-member mixing analysis; Isotopic composition; Multiple timescales; Season precipitation; Seasonal precipitations; Terrestrial ecosystems; Water flux measurement; Winter precipitation; Stream flow; evapotranspiration; hydrological cycle; isotopic composition; precipitation intensity; rainfall-runoff modeling; seasonality; streamflow; streamwater; water flux; water storage; watershed; Hubbard Brook; New Hampshire; United States
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159535
作者单位	W. Kirchner, J., Dept. of Environmental Systems Science, ETH Zurich, Zurich, 8092, Switzerland, Swiss Federal Research Institute WSL, Birmensdorf, 8903, Switzerland, Dept. of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States; T. Allen, S., Dept. of Environmental Systems Science, ETH Zurich, Zurich, 8092, Switzerland, Dept. of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, United States
推荐引用方式 GB/T 7714	W. Kirchner J.,T. Allen S.. Seasonal partitioning of precipitation between streamflow and evapotranspiration; inferred from end-member splitting analysis[J],2020,24(1).
APA	W. Kirchner J.,&T. Allen S..(2020).Seasonal partitioning of precipitation between streamflow and evapotranspiration; inferred from end-member splitting analysis.Hydrology and Earth System Sciences,24(1).
MLA	W. Kirchner J.,et al."Seasonal partitioning of precipitation between streamflow and evapotranspiration; inferred from end-member splitting analysis".Hydrology and Earth System Sciences 24.1(2020).