High-frequency storm event isotope sampling reveals time-variant transit time distributions and influence of diurnal cycles

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

High-frequency sampling of stable water isotopes in precipitation and stream water during winter and summer storm events was carried out in a 2.3 km2 lowland agricultural catchment. During peak flows of monitored events, the responses of delta 2H and delta 18O were comparable and inferred the dominance (ca 70%) of old pre-event water. Transit Time Distribution (TTD) inferred by a gamma function were fitted (Nash-Sutcliffe = 0.8) and were also similar for delta 2H and delta 18O. However, the shape (alpha) and scaling (beta) parameters were markedly different for summer and winter events. Consequently, when antecedent wetness was high, mean transit times were in the order of days; when drier, they increased to months. Moreover, while the responses of delta 2H and delta 18O exhibited similar gradual recovery to pre-event conditions during winter hydrograph recessions, they differed dramatically on summer recessions. Time series analysis showed that delta 2H isotope content was correlated with the diurnal cycle of air temperature, suggesting an evaporative fractionation pattern which could be reproduced by a temperature-based first-order autoregressive model. The heavier delta 18O isotope showed no evidence for such diurnal variability. The study highlights the utility of high-frequency stable isotope sampling to explore the time-variant nature of TTDs. Furthermore, it shows that the time of sampling in a diurnal cycle may have crucial significance for interpreting stream isotope signatures, particularly delta 2H. Copyright (c) 2011 John Wiley & Sons, Ltd.

Original languageEnglish
Pages (from-to)308-316
Number of pages9
JournalHydrological Processes
Volume26
Issue number2
Early online date20 Jul 2011
DOIs
Publication statusPublished - 15 Jan 2012

Keywords

  • stable isotopes
  • conservative tracer
  • fractionation
  • time-variant TTD
  • sampling resolution
  • hydrograph separation
  • tracer data
  • catchment
  • deuterium
  • rainfall
  • systems
  • model

Cite this

@article{f717e8ab5e3a4559ad6354193482813c,
title = "High-frequency storm event isotope sampling reveals time-variant transit time distributions and influence of diurnal cycles",
abstract = "High-frequency sampling of stable water isotopes in precipitation and stream water during winter and summer storm events was carried out in a 2.3 km2 lowland agricultural catchment. During peak flows of monitored events, the responses of delta 2H and delta 18O were comparable and inferred the dominance (ca 70{\%}) of old pre-event water. Transit Time Distribution (TTD) inferred by a gamma function were fitted (Nash-Sutcliffe = 0.8) and were also similar for delta 2H and delta 18O. However, the shape (alpha) and scaling (beta) parameters were markedly different for summer and winter events. Consequently, when antecedent wetness was high, mean transit times were in the order of days; when drier, they increased to months. Moreover, while the responses of delta 2H and delta 18O exhibited similar gradual recovery to pre-event conditions during winter hydrograph recessions, they differed dramatically on summer recessions. Time series analysis showed that delta 2H isotope content was correlated with the diurnal cycle of air temperature, suggesting an evaporative fractionation pattern which could be reproduced by a temperature-based first-order autoregressive model. The heavier delta 18O isotope showed no evidence for such diurnal variability. The study highlights the utility of high-frequency stable isotope sampling to explore the time-variant nature of TTDs. Furthermore, it shows that the time of sampling in a diurnal cycle may have crucial significance for interpreting stream isotope signatures, particularly delta 2H. Copyright (c) 2011 John Wiley & Sons, Ltd.",
keywords = "stable isotopes, conservative tracer, fractionation, time-variant TTD, sampling resolution, hydrograph separation, tracer data, catchment, deuterium, rainfall, systems, model",
author = "Christian Birkel and Christopher Soulsby and Doerthe Tetzlaff and Sarah Dunn and Luigi Spezia",
year = "2012",
month = "1",
day = "15",
doi = "10.1002/hyp.8210",
language = "English",
volume = "26",
pages = "308--316",
journal = "Hydrological Processes",
issn = "0885-6087",
publisher = "Wiley-Blackwell",
number = "2",

}

TY - JOUR

T1 - High-frequency storm event isotope sampling reveals time-variant transit time distributions and influence of diurnal cycles

AU - Birkel, Christian

AU - Soulsby, Christopher

AU - Tetzlaff, Doerthe

AU - Dunn, Sarah

AU - Spezia, Luigi

PY - 2012/1/15

Y1 - 2012/1/15

N2 - High-frequency sampling of stable water isotopes in precipitation and stream water during winter and summer storm events was carried out in a 2.3 km2 lowland agricultural catchment. During peak flows of monitored events, the responses of delta 2H and delta 18O were comparable and inferred the dominance (ca 70%) of old pre-event water. Transit Time Distribution (TTD) inferred by a gamma function were fitted (Nash-Sutcliffe = 0.8) and were also similar for delta 2H and delta 18O. However, the shape (alpha) and scaling (beta) parameters were markedly different for summer and winter events. Consequently, when antecedent wetness was high, mean transit times were in the order of days; when drier, they increased to months. Moreover, while the responses of delta 2H and delta 18O exhibited similar gradual recovery to pre-event conditions during winter hydrograph recessions, they differed dramatically on summer recessions. Time series analysis showed that delta 2H isotope content was correlated with the diurnal cycle of air temperature, suggesting an evaporative fractionation pattern which could be reproduced by a temperature-based first-order autoregressive model. The heavier delta 18O isotope showed no evidence for such diurnal variability. The study highlights the utility of high-frequency stable isotope sampling to explore the time-variant nature of TTDs. Furthermore, it shows that the time of sampling in a diurnal cycle may have crucial significance for interpreting stream isotope signatures, particularly delta 2H. Copyright (c) 2011 John Wiley & Sons, Ltd.

AB - High-frequency sampling of stable water isotopes in precipitation and stream water during winter and summer storm events was carried out in a 2.3 km2 lowland agricultural catchment. During peak flows of monitored events, the responses of delta 2H and delta 18O were comparable and inferred the dominance (ca 70%) of old pre-event water. Transit Time Distribution (TTD) inferred by a gamma function were fitted (Nash-Sutcliffe = 0.8) and were also similar for delta 2H and delta 18O. However, the shape (alpha) and scaling (beta) parameters were markedly different for summer and winter events. Consequently, when antecedent wetness was high, mean transit times were in the order of days; when drier, they increased to months. Moreover, while the responses of delta 2H and delta 18O exhibited similar gradual recovery to pre-event conditions during winter hydrograph recessions, they differed dramatically on summer recessions. Time series analysis showed that delta 2H isotope content was correlated with the diurnal cycle of air temperature, suggesting an evaporative fractionation pattern which could be reproduced by a temperature-based first-order autoregressive model. The heavier delta 18O isotope showed no evidence for such diurnal variability. The study highlights the utility of high-frequency stable isotope sampling to explore the time-variant nature of TTDs. Furthermore, it shows that the time of sampling in a diurnal cycle may have crucial significance for interpreting stream isotope signatures, particularly delta 2H. Copyright (c) 2011 John Wiley & Sons, Ltd.

KW - stable isotopes

KW - conservative tracer

KW - fractionation

KW - time-variant TTD

KW - sampling resolution

KW - hydrograph separation

KW - tracer data

KW - catchment

KW - deuterium

KW - rainfall

KW - systems

KW - model

U2 - 10.1002/hyp.8210

DO - 10.1002/hyp.8210

M3 - Article

VL - 26

SP - 308

EP - 316

JO - Hydrological Processes

JF - Hydrological Processes

SN - 0885-6087

IS - 2

ER -