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Interception effects on stable isotope driven streamwater transit time estimates
Author(s) -
Stockinger Michael P.,
Lücke Andreas,
McDonnell Jeffrey J.,
Diekkrüger Bernd,
Vereecken Harry,
Bogena Heye R.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl064622
Subject(s) - throughfall , tracer , interception , isotope , environmental science , streams , hydrology (agriculture) , stable isotope ratio , watershed , precipitation , atmospheric sciences , geology , meteorology , soil water , soil science , machine learning , biology , computer science , nuclear physics , ecology , computer network , physics , geotechnical engineering , quantum mechanics
Previous studies of streamwater transit time distributions (TTDs) used isotope tracer information from open precipitation (OP) as inputs to lumped watershed models that simulate the stream isotopic composition to estimate TTD. However, in forested catchments passage of rainfall through the canopy will alter the tracer signature of throughfall (TF) via interception. Here we test the effect of using TF instead of OP on TTD estimates. We sampled a 0.39 km 2 catchment (Wüstebach, Germany) for a 19 month period using weekly precipitation and stream isotope data to evaluate changes in stream isotope simulation and TTDs. We found that TF had different effects on TTDs for δ 18 O and δ 2 H, with TF leading to up to 4 months shorter transit times. TTDs converged for both isotopes only when using TF. TF improved the stream isotope simulations. These results demonstrate the importance of canopy‐induced isotope tracer changes in estimating streamwater TTDs in forested catchments.