ABSTRACT
We investigated the influence of post-collection changes and snow gauge undercatch on the stable isotopic compositions of winter precipitation. Post-collection changes by evaporation or sublimation can be severe, and may be minimized, but not eliminated, by emptying collection gauges immediately after snowfall. Snow gauge undercatch caused two main effects: a small direct effect caused by preferential separation of snow particles during snowfall, and a much larger effect on the measured stable isotopic compositions of average annual precipitation as a result of under representation of winter precipitation. Despite these effects, however, we found little change to calculated local meteoric water lines (LMWL) for Saskatoon, SK, Canada. A comprehensive 27-year LMWL for Saskatoon which incorporates these effects can be described by δ2H = 7.69 ± 0.096 × δ18O – 2.22 ± 1.72 (r2 = 0.97, n = 208).
Acknowledgements
We thank Randy Schmidt for field collections and Chantel Gryba, who assisted with stable isotope measurements. J. McDonnell and Garth van der Kamp provided critical and helpful reviews of an earlier version of this manuscript. Two anonymous referees provided additional helpful comments.
Disclosure statement
No potential conflict of interest was reported by the author.
ORCID
Geoff Koehler http://orcid.org/0000-0003-3864-3346