Wednesday, August 18, 2010

Autumn temperature changes

When I moved up onto Keystone Ridge in June 1996, I figured that June would be the month when, on average Keystone Ridge, at 1600' MSL, daily maximum temps would coolest compared to town (i.e. Fairbanks International, 440' MSL). After all, June has the maximum solar insolation and climatologically the fewest days of rainy cool weather; many Junes have no stratiform rain events at all. Well after 15 years of data, I can safely say I was wrong, as the plot at the right shows.

In fact, other contributions make as much or more of an impact on the non-inversion season max temperatures. In the spring, a much longer lasting snowpack on the Ridge helps suppress temps, while in the late summer and early autumn more persistent fog and stratus AND the much lower sun angle, amplified by the northeast aspect of the Keystone Ridge weather station contribute to an even greater deficit. I would not have guessed that in fact September is the month when Ridge is coolest compared to town.

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