[NLRS] Tropo & upper air data

[jcplatt1 at mmm.com]

While Matt was working Ohio and Ont. on 2, 222, and 432, I burped the NWS
upper air data for the Twin Cities.   The table below is a small cut &
paste from the 1200Z upper air balloon data.

The first column is the sequential data points as the data balloon rises
(SFC = surface).   The second column is the air pressure at each data point
while the third column is the computed height above ground (based on air
pressure).   The fourth and fifth column are the measured air temp and dew
points while the last column is the computed relative humidity.

You can see that the air temperature is relatively constant with height,
but look how the dew point drops like a rock at about 1280 meters.    The
classic definition of a tropo duct is warm DRY air over cool wet air.   The
relative humidity of that upper air is 2 to 6%.

-------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH
     mb     m     C     C    %
-------------------------------
  0 1000   180

SFC  987   287  16.4   4.4  45
  2  925   838  12.0   1.0  47
  3  883  1224   8.4  -0.6  53
  4  877  1281  10.0 -19.0  11
  5  874  1309  10.4 -25.6   6
  6  850  1541  11.0 -34.0   3
  7  778  2275   9.0 -38.0   2
  8  752  2555   7.4 -11.6  24
  9  716  2956   4.6  -9.4  35

Here is the 1200z data from Buffalo NY, the other end of the duct.    You
can see the duct at just over 1000 meters.  In this case the upper air is
also warmer than the surface air, not to mention alot drier.   Again, warm
dry air over cool wet air.
------------------------------
LEV PRES  HGHT  TEMP  DEWP  RH
     mb     m     C     C    %
------------------------------
  0 1000   184
SFC  996   215   7.0   2.1  71
  2  932   758   2.0  -0.1  86
  3  925   819   2.8  -0.0  82
  4  903  1015   5.4   0.4  70
  5  897  1069   6.2 -12.8  24
  6  863  1388  10.4 -36.6   2
  7  850  1514  10.4 -33.6   3
  8  711  2978   3.8 -36.2   3
  9  700  3104   3.4 -14.6  25
 10  680  3338   1.8  -9.2  44

Fun stuff, but drat, back to work.

You can see this upper air data at a number of websites.   Here is one:
http://weather.unisys.com/upper_air/skew/index.html

73, Jon
W0ZQ