Re: on the vertical coordinates of the CCM3


Subject: Re: on the vertical coordinates of the CCM3
From: William F. Campbell (valentin@wam.umd.edu)
Date: Mon Apr 06 1998 - 10:02:02 MDT


  On the off chance that your question hasn't been answered yet, I'll
answer it. (BTW, I am at Maryland also). In the CCM3 documentation on
pp 190-191 is the information you seek, though it is not obvious (I just
figured out the answer to your question myself, after some degree of
pondering). Look at the first, third, and fifth columns, which are 1/2
levels. The first column contains the pressure in mb (the so-called A
coefficients). The third column contains 1000 times sigma (the
so-called B coefficients). The fifth column contains the eta
coordinate, and is the sum of the first and third columns (A+B). Note
that the top five 1/2 levels are pure pressure (as the first five
entries in the third column (sigma) are 0), and the bottom two 1/2
levels are pure sigma (as the last two entries in the first column
(pressure) are 0). Eta is always some number times pressure plus some
other number times 1000 times sigma.
  If you are interested in the full levels (which, BTW, are now the
arithmetic means of the 1/2 levels, as opposed to the geometric mean,
which is what they are in the current printed version of the CCM3 docs),
they are listed in columns 2, 4, and 6, and are completely analogous to
columns 1,3, and 5. The top 4 full levels are pure pressure, and the
bottom full level is pure sigma.
  Hope this helps, and good luck -- email me if you have other
questions, but I'm a fairly novice user.

--
Bill Campbell                          Correlation is not cause.
bill@metosrv2.umd.edu



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