Sensitivity Analysis of Mountain Hydrology to Changing Climate
Date
2017-04-20
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ORCID
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Thesis
Degree Level
Doctoral
Abstract
Understanding the sensitivity of hydrological processes to climate change in snow-covered mountains is important for water and energy security. The objectives of this study are: (i) to quantify the sensitivity of simulated mountain hydrological processes to changes in air temperature and precipitation; (ii) to document the uncertainty in estimations of future mountain hydrological processes due to uncertainty in climate models; and (iii) to quantify the response of simulated mountain hydrology to climate change when there are transient changes in vegetation and soils. Three basins are selected for this research: Wolf Creek Research Basin (WCRB), Canada; Marmot Creek Research Basin (MCRB), Canada; and Reynolds Mountain East (RME) catchment, USA. A hydrological model for each basin was set up in the Cold Regions Hydrological Modelling platform (CRHM) and a climate perturbation sensitivity (CPS) analysis was conducted based on a series of annually perturbed climate (APC), monthly perturbed climate (MPC), and transient vegetation changes. Peak snow water equivalent (SWE), evapotranspiration, and annual runoff have a pronounced sensitivity to both warming and precipitation change in all three basins. The timing of snow regime is most sensitive to changes in temperature. The impacts of warming on alpine snow in WCRB and to lesser extent in MCRB can be offset by increases in precipitation. In response to MPC, modelled peak SWE decreases while evapotranspiration and total annual runoff increase. Annual runoff responds very strongly to precipitation increases in MCRB, to warming in RME, and to both precipitation increase and warming in WCRB. Warming increases rainfall fraction of precipitation, as all three snow-dominated basins become more rain-dominated and precipitation phase becomes latitudinally more similar. The impact of climate change is moderated by the impact of vegetation change on peak SWE timing, snow transport, evapotranspiration, and annual runoff. The hydrological uncertainty due to uncertainty in climate models is greater than the range of hydrological changes due to climate change for streamflow regimes in the three basins and snow regimes at high elevations and latitudes. The results of this research can be used to anticipate the hydrological impacts of climate and vegetation changes on mountain environments.
Description
Keywords
Climate Change, Mountain, Hydrology, Rocky Mountains, Cold Regions
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Geography and Planning
Program
Geography