Arctic Snow Isotope Hydrology: A Comparative Snow-Water Vapor Study

Abstract

The Arctic’s winter water cycle is rapidly changing, with implications for snow moisture sources and transport processes. Stable isotope values (δ18O, δ2H, d-excess) of the Arctic snowpack have potential to provide proxy records of these processes, yet it is unclear how well the isotope values of individual snowfall events are preserved within snow profiles. Here, we present water isotope data from multiple taiga and tundra snow profiles sampled in Arctic Alaska and Finland, respectively, during winter 2018–2019. We compare the snowpack isotope stratigraphy with meteoric water isotopes (vapor and precipitation) during snowfall days, and combine our measurements with satellite observations and reanalysis data. Our analyses indicate that synoptic-scale atmospheric circulation and regional sea ice coverage are key drivers of the source, amount, and isotopic composition of Arctic snowpacks. We find that the western Arctic tundra snowpack profiles in Alaska preserved the isotope values for the most recent storm; however, post depositional processes modified the remaining isotope profiles. The overall seasonal evolution in the vapor isotope values were better preserved in taiga snow isotope profiles in the eastern Arctic, where there is significantly less wind-driven redistribution than in the open Alaskan tundra. We demonstrate the potential of the seasonal snowpack to provide a useful proxy for Arctic winter-time moisture sources and propose future analyses.

Subarctic catchment water storage and carbon cycling – Leading the way for future studies using integrated datasets at Pallas, Finland

“…Changes in winter conditions such as snow depth directly influence soil frost condition, i.e. more snow, less soil frost (Ala‐Aho et al, 2021a, 2021b). Additionally, soil freezing controls the biogeochemical activity in the soil, infiltration possibilities and thus impacts the amount of carbon available for export to streams during snowmelt (Haei et al, 2010).…”

“…Examples include retreating seasonal snow cover, increasing temperatures and precipitation, and shifts in precipitation from snow to rainfall (Bring et al, 2016; Hansen et al, 2019; Krasting et al, 2013; Pulliainen et al, 2020). Seasonal soil frost and permafrost conditions are predicted to change substantially (Aalto et al, 2018; Ala‐Aho et al, 2021a, 2021b; Biskaborn et al, 2019; Wang et al, 2019), modifying hydrological pathways and biogeochemical processes (Czimczik & Welker, 2010; Lupascu et al, 2018; Nowinski et al, 2010; Serikova et al, 2018) and causing infrastructure failure (Hjort et al, 2018). The consequences of warming are likely to be severe in subarctic systems in the near future as slight changes in temperature can alter the magnitude and timing of snow accumulation and melt (Carey et al, 2010; Mioduszewski et al, 2014; Richter‐Menge & Druckenmiller, 2020).…”

“…Understanding the complex linkages and interactions between water inputs, storages, water turnover times and outputs, and how hydrology controls biogeochemical cycles and vegetation water usage represents a major challenge in ecohydrology (Guswa et al, 2020). However, substantial progress has been made using water isotope forensics (Ala‐Aho et al, 2021a, 2021b; Bailey et al, 2019; Jespersen et al, 2018; Penna et al, 2018). A better understanding of hydrological processes is especially important in subarctic mosaic landscapes with high variability in connectivity between diverse landscape elements (Laudon & Sponseller, 2018; Lyon et al, 2010).…”

The Spatiotemporal Variability of Snowpack and Snowmelt Water 18O and 2H Isotopes in a Subarctic Catchment

“…Changes in air temperatures, precipitation patterns, and moisture conditions are producing unprecedented changes in snow accumulation and melt in northern regions (Arp et al., 2015; Irannezhad et al., 2022; Kiewiet et al., 2022; Rasouli et al., 2022; Rixen et al., 2022; Ruosteenoja et al., 2020; Vormoor et al., 2015). The changes in magnitude and timing of snow precipitation and snowmelt runoff have gradually resulted in a hydrological regime shift from a snowmelt to a rainfall‐dominated system in cold climate regions (Berghuijs et al., 2014; Bintanja & Andry, 2017), with varying feedbacks at a catchment scale (Ala‐aho et al., 2021; Meriö et al., 2019; Pi et al., 2021). Meltwater is vital for replenishing water storage and exporting solutes and nutrients (Ågren et al., 2010; Tomco et al., 2019).…”

“…Freeze‐thaw and condensation‐sublimation processes result in frequent phase changes of the water (solid‐liquid‐vapor) and cause isotope fractionation in the snowpack (Evans et al., 2016; Hürkamp et al., 2019; Lee et al., 2010; O’Neil, 1968; Stichler et al., 1981; Zhou et al., 2008). Post‐depositional snowpack processes lead to the spatial variability of snowpack and subsequent meltwater 18 O and 2 H isotopic composition (Ala‐aho et al., 2021; Dietermann & Weiler, 2013; Hürkamp et al., 2019; Ohlanders et al., 2013; Siegenthaler & Oeschger, 1980; Sinclair & Marshall, 2008). The usual lapse rate of isotope values in the snowpack (−0.6‰ to about −1.0‰ of $$\delta $$ 18 O per 100 m (Niewodnizański et al., 1981)) is higher than the typically reported lapse rate for precipitation isotopes (−0.2‰ of $$\delta $$ 18 O per 100 m (Siegenthaler & Oeschger, 1980)).…”