Self-tutoring about weather: the tutor loves to bring you this post about a phenomenon that’s long confused him.
This morning, the temp was 6°C at 7am, but 4°C at 8am. The sun rose at 7:35am.
I’ve observed, so often, the temp dropping post sunrise. Yet, how can it make sense?
Finally, I read an explanation which is the best I’ve imagined. Mike Alger, a meteorologist in Reno, explains two key points:
- The thermometer’s position, typically, is several feet above ground. The temperature at ground level might be 5°C colder, since cold air falls.
- At sunrise, the ground starts to heat up, so the air touching it is stirred upwards. Reaching the thermometer, that colder air pulls the reading closer to the temp at ground. It takes the sun’s power to excite those cold air molecules so they bounce up to the thermometer’s level.
Mike observes that the drop in temp after sunrise is most likely on a clear, still morning. I agree. Here, we have dry nights that might turn out rather similar to conditions in Reno. His explanation is the best I can think of.
Source:Oracle Tutoring by Jack and Diane, Campbell River, BC.