On 2 September, when I took these photos, I decided to "test" one of our
sling psychrometers from work to make sure it was taking accurate readings
for relative humidity. I took 5 different readings throughout the day, not
far from my SIMB plot so I though it would be interesting to include the
data. The days started out cool and foggy and then as the day progressed,
it started to clear and become warm. This is a perfect situation for
testing a sling psychrometer since there is such a variation in temperature
during the day and it was damp in the morning, too. Here are the results:
2 September 2012:
Time of day/cloud cover/dry bulb/wet bulb/relative humidity
1)08:50am/100%/5.5°C/5.5°C/100%
2)12:09pm/50%/11.0°C/9.0°C/76%
3)01:55pm/20%/14.0°C/11.0°C/70%
4)04:40pm/60%/15.0°C/11.5°C/66
5)07:40pm/30%/12.0°C/11.0°C/88%
This data shows the classic pattern of the inverse relationship between
relative humidity and temperature (the dry bulb temperature, which is the
ambient air temperature): early in the day, when it is cool, the relative
humidity is high. But as the day warms the rel humidity drops and then at
the end of the day as it cools again, the humidity rises.
Our leaves are
turning bright gold and starting to fall off the trees and we had our first
frost last night. Summer is over!
