Saturday, December 31, 2011

No Solar Heating

Here's the plot of low level temperatures over the past week from a weather station located off the trail behind the IARC Building on UAF West Ridge (there are temperatures from four different heights above the ground). The vertical grid lines are at midnight. This clearly illustrates the lack of solar heating; changes in temperature are being driven entirely by variations in cloud cover.


  1. If there is no solar heating, then why is the day time temperature "always" warmer than the night time, or the minimum low. The sun has to play a small role in raising temperature during the peak sunshine period, and causes a normal diurnal range, am I right? There may not be direct solar heating, due to low sun angle, but the solar warmth from the lower latitudes, from direct sunlight, prob. permeate over the northern latitudes during winter months...

  2. The daytime temperature is not always higher, as the above plot shows. The high temperature for the calendar day was at or near midnight PM on Dec 25, 28 and 30th, and at or near midnight AM on the 26th, 29th and 31st. Note the spike on the 31st is at 5pm, 2 hours after sunset!

    Sure, heating of lower latitudes is sometimes advected (horizontal transport) into high latitudes in winter. Hence the 47F on December 4th.

  3. The day time temperature today was much lower than night time. So it is true that solar heating does not exist at this time of the year. Is this also the case for Anchorage? Thanks