Characterization of surface water isotope spatial patterns of Scotland

Christian Birkel*, Rachel Helliwell, Barry Thornton, Sheila Gibbs, Pat Cooper, Chris Soulsby, Doerthe Tetzlaff, Luigi Spezia, Germain Esquivel-Hernández, Ricardo Sánchez-Murillo, Andrew J. Midwood

*Corresponding author for this work

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The extended National Waters Inventory of Scotland (NWIS) monitoring network in combination with an extensive, supplementary low flow sampling campaign was used to create isoscapes of surface water for management purposes at high spatial resolution (100 m grid) across Scotland. The δ2H isoscape shows a strong isotopic separation along a north-south and east-west topographic (mountainous to the north and west and lowlands to the east) and climatic (wetter west, drier east) gradients. Isotopes were enriched in the western domain and depleted in the east and central Highland domains. The surface water d-excess isoscape show more complex spatial variability mainly related to contrasting moisture sources (sub-tropical North Atlantic Ocean, the North Sea, Polar Continental, and the Arctic) as well as secondary evaporation processes. The two-year NWIS isotope record exhibited a significant seasonal evaporative effect on surface water isotopes that progresses from winter through to a maximum in autumn as indicated by Local Evaporation Lines (LELs). The surface water isoscapes can be efficiently reproduced with geographically weighted regression (GWR) models using gridded annual precipitation, remotely sensed actual evapotranspiration, land cover, soil wetness, catchment area, and mean elevation. The GWR models showed potential to assess isotopic changes under future climate and land use change.

Original languageEnglish
Pages (from-to)71-80
Number of pages10
JournalJournal of Geochemical Exploration
Volume194
Early online date24 Jul 2018
DOIs
Publication statusPublished - 30 Nov 2018

Keywords

  • d-Excess
  • Geographically weighted regression models
  • Isoscapes
  • Scotland
  • Stable isotopes

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Economic Geology

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    Birkel, C., Helliwell, R., Thornton, B., Gibbs, S., Cooper, P., Soulsby, C., Tetzlaff, D., Spezia, L., Esquivel-Hernández, G., Sánchez-Murillo, R., & Midwood, A. J. (2018). Characterization of surface water isotope spatial patterns of Scotland. Journal of Geochemical Exploration, 194, 71-80. https://doi.org/10.1016/j.gexplo.2018.07.011