# hydro

Function for computing the geopotential height using the hydrostatic equation.

## Synopsis

```    function hydro(
p    : float,
tkv  : float,
zsfc : float
)

```

## Arguments

p
pressure (mb) (any dimensionality, last dimension is nlvl)
tkv
temperature (K) at each p (same dimensionality as p)
zsfc
surface geopotential height (gpm) (same dimensions as p, minus the last dimension nlvl)

## Description

Function for computing the geopotential height using the hydrostatic equation. The results are returned in an array with the same dimensions as p and tkv.

No missing values are allowed.

## Example

```begin
p  =(/ 1008.,1000.,950.,900.,850.,800.,750.,700.,650.,600., \
550.,500.,450.,400.,350.,300.,250.,200., \
175.,150.,125.,100., 80., 70., 60., 50., \
40., 30., 25., 20. /)
t  =(/  29.3,28.1,23.5,20.9,18.4,15.9,13.1,10.1, 6.7, 3.1,   \
-0.5,-4.5,-9.0,-14.8,-21.5,-29.7,-40.0,-52.4,   \
-59.2,-66.5,-74.1,-78.5,-76.0,-71.6,-66.7,-61.3, \
-56.3,-51.7,-50.7,-47.5 /)
q  =(/  20.38,19.03,16.14,13.71,11.56,9.80,8.33,6.75,6.06,5.07, \
3.88, 3.29, 2.39, 1.70,1.00,0.60,0.20,0.00,0.00, \
0.00, 0.00, 0.00, 0.00,0.00,0.00,0.00,0.00,0.00, \
0.00, 0.00 /)

zsfc = 17.0
q    =  q*0.001
tkv  = (t+273.15)*(1.+q*0.61)

zh = hydro (p,tkv,zsfc)
end
```

### Reference Manual Control Panel

\$Revision: 1.8 \$ \$Date: 1999/01/05 16:36:11 \$