Introduction To Environmental Geography 1 (Climatology) – Assignment Example
Homework Exercise #3: Annual Temperature Cycle at Maritime and Continental Locations (from Strahler, 1984 Explain the relation between the times of maximum and minimum temperatures and the time of maximum and minimum insolation for :
Auckland, New Zealand (37 S) : Auckland being in the southern hemisphere, experiences the summer season during Dec and Feb. Subsequently, day length (i.e., the duration of insolation) and the angle of incidence of sunlight (which determines the intensity of insolation) which are at their maximum in the summer season, cause maximum insolation. Thus, the surface temperatures show a maximum at the December (or Southern) solistice as the sun moves south of the equator. Again, the insolation values being minimum when the sun moves north of the equator at the June (or Northern) solistice, the temperatures are minimum during winter that is, June to August.
Churchill, Manitoba, Canada (59 N) : At Churchill, Manitoba, Canada which lies in the northern hemisphere, the longest daylengths along with the greatest solar heights (i.e., the angle of incidence of sunlight) occurs in summer, around the June solistice which is reflected in the graph showing the mean monthly temperatures. In contrast to Auckland, New Zealand, the minimum temperatures occur during December to February which is the winter season in the northern hemisphere.
Do maximum/minimum temperatures coincide with maximum/minimum insolation?
The maximum/minimum temperatures generally do coincide with maximum/minimum insolation. However, in some cases there could be a disruption of this relationship due to a delay in the movement of stored heat energy from the ground to the atmosphere (Pidwirny, 2006).
2) Calculate the temperature range for each station.
Auckland: 14F (52F to 66 F); Churchill: 73F (-20F to 53F)
3) Offer two good reasons why the annual range of temperature at Churchill should be so vastly greater than at Auckland.
a) Churchill is located at a higher latitude (59 N) compared to Auckland (37 S). The
rule is that the annual temperature range increases with increasing latitude.
b) From the graph it is seen that for four months of the year (December to March)
mean temperatures are negative, indicating that net radiation during the same
period is negative with outgoing longwave radiation exceeding incoming
insolation. This leads to great variations in mean monthly temperature and a large
annual range of temperature.
Also, Churchill is located on the coast of the Hudson Bay. But since the shallow
Hudson Bay freezes during winter, marine moderation of the temperature does not
occur, resulting in very low winter temperatures. During summer when the Hudson
Bay thaws, marine moderation of the temperature occurs, resulting in a cooler
summer. In contrast, Auckland is close to the Hauraki Gulf which is a part of the
warmer and deeper Pacific Ocean. The temperatures of Auckland are moderated by
the Pacific Ocean; hence, the annual range of temperature at Auckland is not as
high as that at Churchill.
Pidwirny, M. (2006). "Earth-Sun Relationships and Insolation". Fundamentals of Physical Geography, 2nd Edition. Accessed on July 3, 2010 from