Data from "US Standard Atmosphere", 1976, U.S. Goverment
Printing Office, Washington, DC.  Abridged version of
table from B.R. Munson, D.F. Young, and T.H. Okiishi,
"Fundamentals of Fluid Mechanics", 3rd ed., 1998, Wiley, New York
      z        T         p           rho
     (m)      (C)       (Pa)       (kg/m^3)
    -1000     21.50    113900      1.34700
        0     15.00    101300      1.22500
     1000      8.50     89880      1.11200
     2000      2.00     79500      1.00700
     3000     -4.49     70120      0.90930
     4000    -10.98     61660      0.81940
     5000    -17.47     54050      0.73640
     6000    -23.96     47220      0.66010
     7000    -30.45     41110      0.59000
     8000    -36.94     35650      0.52580
     9000    -43.42     30800      0.46710
    10000    -49.90     26500      0.41350
    15000    -56.50     12110      0.19480
    20000    -56.50      5529      0.08891
    25000    -51.60      2549      0.04008
    30000    -46.64      1197      0.01841
    40000    -22.80       287.1    0.003996
    50000     -2.50        79.78   0.001027
    60000    -26.13        21.96   0.0003097
    70000    -53.57         5.221  8.283e-5
    80000    -74.51         1.052  1.846e-5