Page 99 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

visualanalysis 2 Dryland Agriculture
In Canada, the concept of north is something that pervades our national identity. But, how far north is north? When are you south? Traditionally, north was defined as latitude greater than 60° N. A team of ge- ographers at Statistics Canada collaborated to define north using the concept of nordicity—the degree of “northerliness,” a quantitative measure of place that was first calculated in the 1970s. The team exam- ined a wide range of variables, including physical characteristics of climate and biota as well as social and cultural measures, to determine a new definition of north that is portrayed here. This new concept of north consists of four zones: the north, the north transition, the south transition, and the south.
Another parameter that can be considered for de- fining northerliness is the variation in daylength with latitude. Review the variation in daylength seasonally at 50° and 60° in the table below. Consider your own latitude and what effects these changes have.
1. Does seasonal change in daylength play a role in your perception of “north”?
2. What are your own adaptations to seasonal change in daylength times and climate?
3. What is your perception of “north”? How closely does your perception of what is “north” in Canada match the boundaries shown on the map?
60°
150°
30° North Smootthed
165° 150°
ARCTIC OCEAN
135°
120°
105°
90°
Chapter 2 Solar Energy to Earth and the Seasons 63
60°
75°
45°
45°
Latitude a.m.
0° 6:00 30° 6:58 40° 7:30 50° 8:05 60° 9:15 90°
p.m. Daylength a.m. p.m. Daylength a.m. p.m. Daylength a.m. p.m. Daylength
6:00 12:00 6:00 6:00 12:00 6:00 6:00 12:00 6:00 6:00 12:00 5:02 10:04 6:00 6:00 12:00 5:02 6:58 13:56 6:00 6:00 12:00 4:30 9:00 6:00 6:00 12:00 4:30 7:30 15:00 6:00 6:00 12:00 3:55 7:50 6:00 6:00 12:00 3:55 8:05 16:10 6:00 6:00 12:00 2:45 5:30 6:00 6:00 12:00 2:45 9:15 18:30 6:00 6:00 12:00 No sunlight Rising Sun Continuous sunlight Setting Sun
PACIFIC Smoothed
OCEAN
135°
North
South
250 500 KILOMETRES
Noortrhth–- Soutth Linine
Smootthed Soutth 45°
Trransiittiion Liine
ATLANTIC OCEAN
60° North–South Indicator Lines
0
Adapted from Delineation of Canada’s North: An Examination of the North–South Relationship in Canada, Statistics Canada, catalogue 92F0138, February 3, 2000, map 4.
Daylength Times (Sunrise and Sunset) at Selected Latitudes (Northern Hemisphere)
Vernal Equinox Winter Solstice (December (March Equinox)
Solstice) December 21–22 March 20–21
Summer Solstice (June Solstice) June 20–21
Autumnal Equinox (September Equinox) September 22–23
Note: All times are standard and do not consider the local option of daylight saving time.
Transition Line