Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Geography & Environmental Studies

Program Name/Specialization

Environmental Science

Faculty/School

Faculty of Arts

First Advisor

Philip Marsh

Advisor Role

Supervisor

Abstract

Multidecadal Changes in Spring Snowmelt in the Western Canadian Arctic

This study investigates the changes in key aspects of snowmelt in the western Canadian Arctic. Specifically, we will look at changes in the onset of snowmelt and the duration of snowmelt between 1999 and 2019, and extended air temperature between 1957 and 2019. In addition, we will look at changes in eight meteorological variables during the melt period. It was found that the onset of snowmelt occurred 14 days earlier, while the melt period ends 20 days earlier than 20 years ago. As a result, the duration of melt period has decreased by 5 days. During this earlier and shorter melt period, the air temperature and relative humidity have both increased. While these changes were statistically significant, there were no statistically significant changes in SWE, precipitation, wind speed, downward shortwave and longwave radiation, or refreeze events. Future research will consider the effects and the variability of these changes on the snowmelt energy balance.

Changing Snowmelt Energy Balance in the Western Canadian Arctic

The hydrology of the of the Arctic is dominated by the accumulation of snow over the long winter, and the rapid melt of this snow over a few weeks in the spring. This aspect of the Arctic water cycle is especially sensitive to a warming climate. The timing and the rate of snow melt during the spring period has implications for aquatic ecosystems and communities that depend on melt water. As shown in Chapter 2, the western Canadian Arctic has experienced an earlier onset of snowmelt compared to earlier decades, a warmer and shorter melt period. The changes in the energy balance components are tied to climate warming, and therefore, controlling the rate of snowmelt. In this paper we will use a physically based snowmelt model to investigate changes in the energy transfers between the snow surface and the atmosphere during the snowmelt period over the last 21 years. Model runs demonstrate that radiation plays a decisive role, followed by turbulent fluxes of sensible heat and latent heat. A shorter duration of melt is due to a combination of changes in the end of winter SWE and meteorological conditions. As net radiation and warmer air temperatures increased, we found an increase to the rate of snowmelt by 0.7 mm/day per decade.

Convocation Year

2022

Convocation Season

Spring

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Hydrology Commons

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