Air and Climate

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CLIMATE

Indicators

  • Air temperature
  • Precipitation
  • Evaporation

Current Knowledge

The Mackenzie Valley has variety of climatic regions. The weather and climate of these regions is influenced by latitude, by the amount of solar radiation (energy) absorbed or reflected by snow, water and vegetation cover, by topography, and by weather systems in surrounding areas.

Climate is defined in terms of temperature and precipitation. Temperatures in the NWT are cold in winter, with monthly average temperatures of -25 to -30 °C. Summers are warm, with monthly average temperatures of 15 to 20 °C. Precipitation varies with altitude and latitude, and is about equally split between summer and winter. During fall and early winter, systems moving from the West and Southwest bring much of the NWT's snowfall, whereas systems entering the region from the Northwest provide little moisture for most of the winter. Forest cover extends over a major portion of the NWT and interacts with the atmosphere in ways that may influence climate. Forest fires also play a role in the northern climate.

Information shows that temperatures in the NWT have been increasing over the past 50 years, mostly in the winter. Total annual amounts of precipitation (rain and snow) have stayed the same, except that less may be arriving as snow and more as rain. Climate will likely continue to change, with much warmer winters and perhaps more thunderstorms and lightning-caused forest fires. Land use practices which may lead to cumulative impacts on climate include: deforestation along roadways, seismic lines, drill sites and pipelines; access roads leading to increased human use and associated increases in human-caused forest fires; and mining such as large diamond mines that cause wind-blown dust leading to earlier snowmelt.


Current Monitoring

  • Daily monitoring of climatic variables - Environment Canada (EC)
  • Global climate change models - EC, Canadian Centre for Climate Modelling and Analysis
  • Upper air monitoring program - EC
  • Global Energy and Water Cycle Experiment (GEWEX) - World Climate Research Programme
  • Studies of Environmental Effects of Disturbances in the Subarctic (SEEDS) - University of Alberta
  • Ecological and geomorphological studies in the Mackenzie Mountains - University of Alberta
  • Northern Climate Exchange - Northern Research Institute, Yukon College
  • Lightning Monitoring Programs - Government of the Northwest Territories (GNWT), EC
  • NWT Evaporation Network - Indian and Northern Affairs Canada (INAC)
  • Dendrochronology sampling and analysis - INAC
  • Daring Lake Research Station - GNWT
  • Tibbitt Lake Post Fire Microclimate Study - GNWT and INAC

Gaps and Recommendations

Long-term climate information is lacking throughout most of the NWT, since there are not many weather stations. As a result, only short-term patterns can currently be identified. Continued and expanded monitoring is needed to detect real long-term changes in climate.

More weather stations are needed, especially in:

  • The Mackenzie Mountains
  • Mackenzie River, East Channel
  • North of Great Bear Lake
  • The Coppermine River Basin
  • The North and South Slave Regions

Monitoring of indicators should be conducted in areas of proposed or possible development, and at locations where water quantity, snow and permafrost are already being monitored.

Trends and proxy data (such as tree rings) need to be studied to determine past, and predict future, trends including the reconstruction of past climate and streamflow history of the NWT.

This summary is based on:  A Preliminary State of Knowledge of Valued Compnents for the NWT Cumulative Impact Monitoring Program (NWT CIMP) and Audit. February, 2002; updated February 2005.

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