Document Type

Thesis

Degree Name

Master of Environmental Studies (MES)

Department

Geography & Environmental Studies

Faculty/School

Faculty of Arts

First Advisor

Michael English

Advisor Role

Thesis Supervisor

Second Advisor

Richard Petrone

Advisor Role

Thesis Supervisor

Abstract

Determining the extent to which changes in vegetation assemblages influence evapotranspiration in the Arctic could potentially contribute to a more realistic estimation of evaporation in a warming climate.

This project aims to determine whether variations in PET and AET rates measured at six tundra vegetation communities can be attributed to the differing vegetation. This will provide a more realistic estimate of change in the water and energy cycles, as well as evaporative processes for a warmer future, caused by enhanced global warming. Predictions of temperature and precipitation regarding future climate in Canada’s Western low Arctic vary greatly. The majority of existing Global Climate Models, regardless of how predicted precipitation increases, indicate that the moisture deficit in the Canadian arctic will grow, due to an increase in evaporation.

Weighted mean AET was estimated for the year 2040 using four scenarios detailing differing changes in summer air temperature and soil moisture. Given a new distribution of plant communities, it was found that any differences in mean temperature produced negligible effects on forecast ET, whereas an increasing soil moisture deficit lead to lower ET.

Evapotranspiration was estimated using field data obtained at Daring Lake, NWT, between June 21 and August 18, 2006. Potential evapotranspiration (PET) was quantified using the Priestly-Taylor method. Results ranged varied between 2.2 and 5.6 mm/day and varied between sites. Actual evapotranspiration (AET) was quantified using a series of lysimeters in five different vegetation communities. Lysimeter results ranged between 1.3 and 3.2 mm/day. Using and ICONOS imaging map of the Daring Lake region (Figure 3.6), coverage was estimated each sampled vegetation community and a weighted mean AET for the Daring Lake Study Site was calculated: 2.2 mm/day.

Convocation Year

2007

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