Abstract:The hydrological sensitivity of a northern Canadian mountain basin to change in temperature and precipitation was examined. A physically based hydrological model was created and included important snow and frozen soil infiltration processes. The model was discretized into hydrological response units in order to simulate snow accumulation and melt regimes and basin discharge. Model parameters were drawn from scientific studies in the basin except for calibration of routing and drainage. The model was able to simulate snow surveys and discharge measurements with very good accuracy. The forcing inputs of the hourly air temperatures and daily precipitation were scaled linearly to examine the model sensitivity to conditions included in a range of climate change scenarios: warming of up to 5°C and change in precipitation of +/À 20%. The results show that peak seasonal snow accumulation, snow season length, evapotranspiration, runoff, peak runoff, and the timing of peak runoff have a pronounced sensitivity to both warming and precipitation change, where the impact of warming is partly compensated for by increased precipitation and dramatically enhanced by decreased precipitation. The snow regime, including peak snow accumulation, snow-free period, intercepted snow sublimation, and blowing snow transport, was most sensitive to temperature, and the impact of a warming of 5°C could not be compensated for by a precipitation increase of 20%. However, basin discharge was more sensitive to precipitation, and the impact of warming could be compensated for by a slight increase in precipitation. The impacts of 5°C warming with a +/À20% change in precipitation resulted in snow accumulation, runoff, and peak streamflow decreasing by from one half to one fifth and the snow-free period lengthening by from 46 to 60 days; in both cases, the smaller change is associated with increased precipitation and the larger change with decreased precipitation. These results show that mountain hydrology in Northern Canada is extremely sensitive to warming, that snow regime is more sensitive to warming than streamflow and that changes in precipitation can partly modulate this response.

Isotope ratio (IR) analysis of natural abundance uranium presents a formidable challenge for mass spectrometry (MS): the required spectral dynamic range needs to enable the quantitatively accurate measurement of the 234UO2 species present at ∼0.0053% isotopic abundance. We address this by empowering a benchtop Orbitrap Fourier transform mass spectrometer (FTMS) coupled with the liquid sampling–atmospheric pressure glow discharge (LS-APGD) ion source and an external high-performance data acquisition system, FTMS Booster X2. The LS-APGD microplasma has demonstrated impressive capabilities regarding elemental and IR analysis when coupled with Orbitrap FTMS. Despite successes, there are limitations regarding the dynamic range and mass resolution that stem from space charge effects and data acquisition and processing restrictions. To overcome these limitations, the FTMS Booster was externally interfaced to an LS-APGD Q Exactive Focus Orbitrap FTMS to obtain time-domain signals (transients) and to process unreduced data. The unreduced time-domain data acquisition with user-controlled processing permit the evaluation of the effects of in-hardware transient phasing, increased transient lengths, advanced transient coadding, varying the length of a transient to be processed with a user-defined time increment, and the use of absorption-mode FT (aFT) processing methods on IR analysis. The added capabilities extend the spectral dynamic range of the instrument to at least 4–5 orders of magnitude and provide a resolution improvement from ∼70k to 900k m/Δm at 200 m/z. The empowered LS-APGD Orbitrap platform allows for the simultaneous measurement of 234UO2 and the prominent 235UO2 and 238UO2 isotopic species at their natural abundances, ultimately yielding improvements in performance when compared to previous uranium IR results on this same Q Exactive Focus instrument.

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Abstract. A set of hydrometeorological data is presented in this paper, which can be used to characterize the hydrometeorology and climate of a subarctic mountain basin and has proven particularly useful for forcing hydrological models and assessing their performance in capturing hydrological processes in subarctic alpine environments. The forcing dataset includes daily precipitation, hourly air temperature, humidity, wind, solar and net radiation, soil temperature, and geographical information system data. The model performance assessment data include snow depth and snow water equivalent, streamflow, soil moisture, and water level in a groundwater well. This dataset was recorded at different elevation bands in Wolf Creek Research Basin, near Whitehorse, Yukon Territory, Canada, representing forest, shrub tundra, and alpine tundra biomes from 1993 through 2014. Measurements continue through 2018 and are planned for the future at this basin and will be updated to the data website. The database presented and described in this article is available for download at https://doi.org/10.20383/101.0113.