Timing and duration of hydrological transitions in Arctic polygonal ground from stable isotopes
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Dartmouth College, Hanover, NH (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Land surface models and Earth system models that include Arctic landscapes must capture the abrupt hydrological transitions that occur during the annual thaw and deepening of the active layer. In this work, stable water isotopes (δ2H and δ18O) are used to appraise hydrologically significant transitions during annual landscape thaw at the Barrow Environmental Observatory (Utqiaġvik, Alaska). These hydrologically significant periods are then linked to annual shifts in the landscape energy balance, deduced from meteorological data and described by the microclimatic periods: Winter, Pre-Melt, Melt, Post-Melt, Summer, and Freeze-Up. The tight coupling of the microclimatic periods with the hydrological transitions supports the use of microclimatic periods as a means of linking polygonal surface water hydrology to meteorological datasets, which provides a mechanism for improving the representation of polygonal surface water hydrology in process-based models. Rayleigh process reconstruction of the isotopic changes revealed that 19% of winter precipitation was lost to sublimation prior to melting and that 23% of surface water was lost to evaporation during the first 10 days post-melt. This agrees with evaporation rates reported in a separate study using an eddy covariance flux tower located nearby. An additional 17% was lost to evaporation during the next 33 days. Stable water isotopes are also used to identify the dominant sources of surface water to various hydrogeomorphological features prevalent in polygonal terrain (a lake, a low centre polygon centre, troughs within the rims of low centre polygons, flat centre polygon troughs, a high centre polygon trough, and drainages). Hydrogeomorphologies that retained significant old water or acted as snow drifts are isotopically distinct during the Melt Period and therefore are easily distinguished. Finally, biogeochemical changes related to the annual thaw are also reported and coupled to the hydrological transitions, which provides insight into the sources and sinks of these ions to and from the landscape.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
- Contributing Organization:
- Next-Generation Ecosystem Experiments (NGEE) Arctic Project
- Grant/Contract Number:
- 89233218CNA000001; AC05-00OR22725
- OSTI ID:
- 1601399
- Alternate ID(s):
- OSTI ID: 1573842
OSTI ID: 1669774
- Report Number(s):
- LA-UR--19-22686
- Journal Information:
- Hydrological Processes, Journal Name: Hydrological Processes Journal Issue: 3 Vol. 34; ISSN 0885-6087
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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