Labs 68 Reports

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Labs 6/8 Reports
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Meteorological Resources

• Environment Canada (www.weatheroffice.gc.ca)
• Canadian Climate Database (www.climate.weatheroffi
  ce.ec.gc.ca)
• UNBC Weather (weather.unbc.ca)
• BC Ministry of the Environment (http//wlapwww.gov
  .bc.ca8000/pls/aqiis/ air.summary)

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UNBC Weather Data
Day Hour T(7m) W_spd W_dir W_std
Kdown Q Ldown T(3m) RH(3m)
Stn_Pres MSLP 297 1910 3.224 3.5492
286.19 0 0 -37.631 231.06 3.6695
43.742 925.05 1015.4 See the link to the
file containing the data under the items for lab
8. Note that -99999 implies no data
available. Finally, note also the link to photos
of the deployment site on the course webpage.
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UNBC Weather Data
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Effects of Topography

• First let us discuss the effect of radiation
  loading.
• The angle at which radiation strikes a surface is
  important in determining the amount of radiation
  it receives that in part determines its climate.
• The effects of aspect and slope are most dramatic
  at higher latitudes where the sun is at a lower
  angle anyway.
• South facing slopes get more radiant energy than
  horizontal and north facing slopes.
• Note this effect is only important for direct
  beam radiation.

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• Net radiation can be 2-4 times higher by day on a
  south facing slope ? results in higher QH (if
  water is limiting).
• This results in distinctly different
  micro-climates and vegetation.

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Topographically-generated winds

• These arise due to thermal differences because of
  slope/aspect.
• Tend to occur under cloudless skies with little
  or no synoptic-scale winds.
• The strength and nature of flows depend on
  orientation and configuration of the valley.
• By day, air near valley sides will be heated more
  than air at same elevation in centre of valley ?
  anabatic cloud formation along ridges.

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• Complex topography can lead to the formation of
  anabatic and katabatic winds.
• Anabatic winds are upslope winds driven by
  surface heating (usually daytime insolation) at
  the slope surface under fair-weather conditions.
• Katabatic winds denote a downslope flow driven by
  cooling at the slope surface during periods of
  light larger-scale winds.

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• This circulation warms the entire valley so that
  it is warmer than neighbouring plains and an up
  valley (valley wind) develops, whereas an
  anti-valley wind develops above the ridges.
• This system will tend to reverse at night.

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Oke (1987)
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Whiteman (2000)
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Oke (1987)
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Oke (1987)
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Oke (1987)