海面気圧の求め方(NCEP/NCAR Reanalysis データの場合)

                         Mean Sea-Level Pressure
                         ---- --------- --------

There are many ways to compute the sea-level pressure.  Some 
expressions only depend on the 1000 mb height.  GDAS and
Reanalysis, however, use the following Fortran code


c               *** gdas - in mb ***
c               slp(i)=1000.0*exp(z1000(i)/
c     2                 (1.5422885*(z500(i)-z1000(i))))
c               *** grib - in Pascals ***
                slp(i)=100000.0*exp(z1000(i)/
     2                  (1.5422885*(z500(i)-z1000(i))))

The corresponding GrADS code is,

   100000*exp(hgt(lev=1000)/(1.5422885*(hgt(lev=500)-hgt(lev=1000))))