Synoptic controls on the surface energy and water budgets in sub-arctic regions of Canada

✍ Scribed by Richard M. Petrone; Wayne R. Rouse

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 513 KB
• Volume: 20
• Category: Article
• ISSN: 0899-8418
• DOI: 10.1002/1097-0088(200008)20:10<1149::aid-joc527>3.0.co;2-m

✦ Synopsis

An objective hybrid classification of daily surface weather maps for central and western Canadian sub-arctic locations was used to determine their dominant synoptic conditions during the snow free period. This classification yielded seven dominant synoptic types for each location during the snowmelt and snow-free periods (20 April -7 September), accounting for 90% of the days in period. The effects of source regions were used to explain the observed air mass characteristics, and their influence on the respective study locations. Cooler, drier air masses were the most frequent at both study locations. Arctic high pressure cells to the northeast brought the coolest air to the western sub-arctic site, Trail Valley Creek (TVC), Northwest Territories, while high pressure systems approaching from the northwest brought the coolest conditions to the central sub-arctic site, Churchill, Manitoba. Sub-tropical high pressure approaching from the west-southwest brought warm air to TVC, whereas stationary high pressure to the south warmed Churchill. These synoptic regimes exerted strong controls on the precipitation and evaporation components of the water balance as observed in terms of cloud cover, radiation and precipitation and evaporation efficiencies.