Monday, May 27, 2013

Cold, this Morning.

Not here, but up North.  It seems that there's a frost warning out for portions of the Northeast.  I wonder if brother David got any snow up in Vermont?

However, I did learn something from reading the article.  Did you know that temperature forecasts are based on eye-level?  I had no idea.
"Temperature forecasts are made for eye-level. However, temperatures near the ground on clear, calm nights can be 5 to 10 degrees lower for several hours, especially around and just prior to sunrise," Sosnowski continued.
So, Milady asks, "Who's eye level?  If the forecaster is 6'2", and I stand 5'2", whose eye level are we using?  Good question, Milady!


Rivrdog said...

The only eye level referred to in weather lore is for growing corn, which should be as high as an elephant's eye when fully mature.

I believe the eye level you have referred to is in NOAA's Instruction 10-1302 (Oct 4, 2005) for siting a weather observation station. 4 to 6 feet for the air intake of a remote sensor. Wind readings are supposed to be taken 33 feet (10 meters) off the ground.

The science behind this air temperature height requirement is all about cold-air pooling, which, as you suggest, can be extreme in a very short air-column.

Cybrludite said...

I recall there being a similar effect when measuring fallout. A couple feet of air will block alpha particles, so what might look safe from a gieger counter probe held at about shoulder-height by an adult could be very bad indeed for young-uns.