TY  - JOUR
AU  - Rothfuss, Y.
AU  - Merz, S.
AU  - Vanderborght, J.
AU  - Hermes, Normen
AU  - Weuthen, A.
AU  - Pohlmeier, A.
AU  - Vereecken, H.
AU  - Brüggemann, N.
TI  - Long-term and high-frequency non-destructive monitoring of water stable isotope profiles in an evaporating soil column
JO  - Hydrology and earth system sciences
VL  - 19
IS  - 10
SN  - 1607-7938
CY  - Katlenburg-Lindau
PB  - EGU
M1  - FZJ-2015-06171
SP  - 4067 - 4080
PY  - 2015
AB  - The stable isotope compositions of soil water (δ2H and δ18O) carry important information about the prevailing soil hydrological conditions and for constraining ecosystem water budgets. However, they are highly dynamic, especially during and after precipitation events. In this study, we present an application of a method based on gas-permeable tubing and isotope-specific infrared laser absorption spectroscopy for in situ determination of soil water δ2H and δ18O. We conducted a laboratory experiment where a sand column was initially saturated, exposed to evaporation for a period of 290 days, and finally rewatered. Soil water vapor δ2H and δ18O were measured daily at each of eight available depths. Soil liquid water δ2H and δ18O were inferred from those of the vapor considering thermodynamic equilibrium between liquid and vapor phases in the soil. The experimental setup allowed for following the evolution of soil water δ2H and δ18O profiles with a daily temporal resolution. As the soil dried, we could also show for the first time the increasing influence of the isotopically depleted ambient water vapor on the isotopically enriched liquid water close to the soil surface (i.e., atmospheric invasion). Rewatering at the end of the experiment led to instantaneous resetting of the stable isotope profiles, which could be closely followed with the new method.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000364327800003
DO  - DOI:10.5194/hess-19-4067-2015
UR  - https://juser.fz-juelich.de/record/256187
ER  -