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Temperature Readings Just Improved!

Custom Davis radiation shield

There was a Problem?

So perhaps you’ve noticed lately on sunny days forecasted highs have been lower than the actual highs by several degrees. Well… it turns out that’s not entirely true.

During the deepest part of winter when the polar vortex was regularly occurring (late December into January), we were having equipment issues. Normally, we measure temperatures inside an enclosure that has a fan running on solar power during the day and batteries at night. Unfortunately, the weather destroyed the electronics that controlled the battery charging, among other casualties.

As a quick fix, we installed a passive (fan-less) shield for our sensor. Passive shelters are fine during our normally very cloudy, windy winters. Wouldn’t you know it, the sun decided to show up and, along with it, gentle breezes! That makes for beautiful winter days in Marquette. It is also a recipe for solar-induced sensor errors.

The snow acts like a mirror to the sun and the reflected radiation gets into the sensor and heats it up. How much? A rough estimate, based on before and after tests of running with and without a fan, is 3-5 degrees F. Studies have shown that, in fact, on completely calm, sunny days over a fresh blanket of snow, errors can reach up to 18 deg F! Continue reading “Temperature Readings Just Improved!”

Is All This Sunshine Getting You Down?

Lilac, the Marquette Weather Dog, enduring pesky prisms

How about the mornings where town is 20 or 30 degrees warmer than nearby locations?

Ice forming on the lake, partially cutting off cloud formation, seems to be helping brighten the long winter. In time, we may be joining the subzero parade once the lake gives off the last of its heat.

Looks like a very nice weekend ahead if you don’t mind slightly below normal temps.

The following weekend it may be TOO warm (near freezing). I hear the sled doggies (UP 200) like it a bit colder. Like below zero. Anyone know if that’s true?

How would you rate this winter so far?

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