Disentangle Kinetic From Equilibrium Fractionation Using Primary (δ17O, δ18O, δD) and Secondary (Δ17O, dex) Stable Isotope Parameters on Samples From the Swiss Precipitation Network

Abstract

Since 1971 water isotope measurements are being conducted by the Climate and Environmental Physics Division at the University of Bern on precipitation, river- and groundwater collected at several places within Switzerland. The water samples were stored in glass flasks for later analyses with improved instrumentation. Conventional isotope ratio measurements on precipitated water from all stations of the network are well correlated as expected. However, Δ17O as well as dex is anticorrelated to these isotope ratio. The combination of these parameters allow to investigate dependencies on temperature, turbulence factor, and humidity of these values as well as to look into the importance and relative contributions of kinetic to equilibrium fractionations. We used published temperature dependent fractionation factors in combination with a simple Rayleigh model approach to investigate the importance of the meteorological parameters on the isotope ratios. A direct comparison of measured and modeled isotope ratios for primary (δ17O, δ18O and (δD) as well as secondary isotope parameters (Δ17O and dex) is shown.

Studying the dynamic of a high alpine catchment based on multiple natural tracers

“…Our computed 17 O-excess values of rainfall (Figure 4 G) are much higher than the few published values in Switzerland, which range from 6.5 per meg (Leuenberger and Ranjan, 2021) to 18 per meg (Affolter et al, 2015) for low and high elevation locations. There are no published values for snowfall or snowpack for Switzerland, but values between 17 and 62 per meg for freshly precipitated snow on Mount Zugspitze (German Alps, 2,962 masl) are found in the work of Surma et al (2021).…”

“…The sampled rainfall has a median d-excess of 11.3 ‰, which is in the range of published values for rainfall in the Swiss Alps (Leuenberger and Ranjan, 2021). The snowpack samples have a median value of 15.5 ‰.…”

Quantifying the Fingerprint of Oceanic Moisture Source Conditions in Deuterium and 17O Excess Parameters of Precipitation

“…At present, precipitation Δ′ 17 O data are available in a few case studies of specific sites. There are 12 sites that have reported precipitation Δ′ 17 O data for at least 2 yr, with eight sites in Switzerland (Affolter et al., 2015; Leuenberger & Ranjan, 2021) and others in Singapore (He et al., 2021), Okinawa Island (Uechi & Uemura, 2019), Indianapolis in the U.S. (Tian & Wang, 2019), and the Pyrenees in Spain (Giménez et al., 2021). All these sites contain paired d‐excess data.…”

“…Their amount-weighted 12 monthly and annual mean d-excess and Δ′ 17 O values are either available or calculated here. Arithmetic mean values are used for seven Switzerland sites where precipitation amount data are unavailable (Leuenberger & Ranjan, 2021).…”

Triple oxygen isotope ratios of bioapatite

“…The drinking water (FDW) composition is considered to represent local meteoric water (δ 18 ODW, Δ' 17 ODW) which varies with locality, climate, and environment (Dansgaard, 1964;Gat 1996, Gat et al 2001. For roe deer from Germany, we took δ 18 ODW = -8 ± 2‰ (Bowen and Revenaugh, 2003;Bowen, 2018) and Δ' 17 ODW = 0.022 ± 0.005‰, a value that can be considered as representative for average Central European precipitation and water bodies Affolter et al, 2015;Leuenberger and Ranjan, 2021).…”