Ticker for January 7, 2003

                
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January 7, 2003    January 7, 2003    January 7, 2003    January 7, 2003


Now Showing: Heat Characteristics!

They say that a picture is worth a thousand words, but we'll spare
you that agony today and try to land around 250 or so.

The following snapshot, from a randomly-selected backyard in Norman,
was taken on December 23rd, shortly after a snow episode:



There are a couple of subtle features in the photo worth talking
about, other than the obvious need to prune a few rose canes.

The first is the melted snow on the patio in the foreground,
demonstrating quite effectively the large specific heat of concrete.
In other words, it takes a lot more heating/cooling to move concrete's
temperature around than, say, the grassy areas in the background.
Thus, the concrete remained above freezing for much longer than the
grassy areas.

The two scalloped snow-free areas on the lawn represent another fun
feature.  An hour or so before this picture was taken, these areas
were as snowy as the rest of the yard!  So what happened?

About a month ago, the Ticker addressed the role of cloud cover
in regulating overnight temperatures on calm nights:

https://content.mesonet.org/ticker/archive/tickselect.cgi?mo=12&da=13&yr=2002

Well, clouds aren't the only things that can re-radiate energy.  The
scalloped areas rest beneath tall elm trees.  And branches, even
scraggly, bare, winter branches, can do some re-radiation of their own!
The result: a couple of tree-shaped areas of melted snow (the foremost
area was also helped out by the shed).

Now, if you don't mind, the Ticker staff has some roses to prune.