气候变化领域集成服务门户(CCPortal): Studying catchment storm response using event- A nd pre-event-water volumes as fractions of precipitation rather than discharge

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DOI	10.5194/hess-22-5847-2018
	Studying catchment storm response using event- A nd pre-event-water volumes as fractions of precipitation rather than discharge
	Von Freyberg J.; Studer B.; Rinderer M.; Kirchner J.W.
发表日期	2018
ISSN	1027-5606
起始页码	5847
结束页码	5865
卷号	22 期号:11
英文摘要	Catchment response to precipitation is often investigated using two-component isotope-based hydrograph separation, which quantifies the contribution of precipitation (i.e., event water Qe) or water from storage (i.e., pre-event water Qpe) to total discharge (Q) during storm events. In order to better understand streamflow-generating mechanisms, two-component hydrograph separation studies often seek to relate the event-water fraction Qe•Q to storm characteristics or antecedent wetness conditions. However, these relationships may be obscured because the same factors that influence Qe also necessarily influence total discharge Q as well. Here we propose that the fractions of event water and pre-event water relative to total precipitation (Qe•P and Qpe•P), instead of total discharge, provide useful alternative tools for studying catchment storm responses. These two quantities separate the well-known runoff coefficient (Q•P, i.e., the ratio between total discharge and precipitation volumes over the event timescale) into its contributions from event water and pre-event water. Whereas the runoff coefficient Q•P quantifies how strongly precipitation inputs affect streamflow, the fractions Qe•P and Qpe•P track the sources of this streamflow response. We use high-frequency measurements of stable water isotopes for 24 storm events at a steep headwater catchment (Erlenbach, central Switzerland) to compare the storm-to-storm variations in Qe•Q, Qe•P and Qpe•P. Our analysis explores how storm characteristics and antecedent wetness conditions affect the mobilization of event water and pre-event water at the catchment scale. Isotopic hydrograph separation shows that catchment outflow was typically dominated by pre-event water, although event water exceeded 50 % of discharge for several storms. No clear relationships were found linking either storm characteristics or antecedent wetness conditions with the volumes of event water or pre-event water (Qe, Qpe), or with event water as a fraction of discharge (Qe•Q), beyond the unsurprising correlation of larger storms with greater Qe and greater total Q. By contrast, event water as a fraction of precipitation (Qe•P) was strongly correlated with storm volume and intensity but not with antecedent wetness, implying that the volume of event water that is transmitted to streamflow increases more than proportionally with storm size under both wet and dry conditions. Conversely, pre-event water as a fraction of precipitation (Qpe•P) was strongly correlated with all measures of antecedent wetness but not with storm characteristics, implying that wet conditions primarily facilitate the mobilization of old (pre-event) water, rather than the fast transmission of new (event) water to streamflow, even at a catchment where runoff coefficients can be large. Thus, expressing event- A nd pre-event-water volumes as fractions of precipitation rather than discharge was more insightful for investigating the Erlenbach catchment's hydrological behaviour. If Qe•P and Qpe•P exhibit similar relationships with storm characteristics and antecedent wetness conditions in other catchments, we suggest that these patterns may potentially be useful as diagnostic "fingerprints" of catchment storm response. © 2018 Author(s).
语种	英语
scopus关键词	Catchments; Isotopes; Runoff; Separation; Stream flow; Generating mechanism; Headwater catchment; High frequency measurements; Hydrograph separation; Precipitation volume; Runoff coefficients; Stable water isotopes; Streamflow response; Storms; catchment; discharge; headwater; hydrographic survey; isotopic composition; outflow; precipitation (climatology); separation; storm; streamflow; volume transport; Switzerland
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/159858
作者单位	Von Freyberg, J., Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland; Studer, B., Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland; Rinderer, M., Department of Hydrology, University of Freiburg, Freiburg im Breisgau, Germany; Kirchner, J.W., Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
推荐引用方式 GB/T 7714	Von Freyberg J.,Studer B.,Rinderer M.,et al. Studying catchment storm response using event- A nd pre-event-water volumes as fractions of precipitation rather than discharge[J],2018,22(11).
APA	Von Freyberg J.,Studer B.,Rinderer M.,&Kirchner J.W..(2018).Studying catchment storm response using event- A nd pre-event-water volumes as fractions of precipitation rather than discharge.Hydrology and Earth System Sciences,22(11).
MLA	Von Freyberg J.,et al."Studying catchment storm response using event- A nd pre-event-water volumes as fractions of precipitation rather than discharge".Hydrology and Earth System Sciences 22.11(2018).