module constants_mod¶
Overview¶
Defines useful constants for Earth in mks units.
Constants are defined as real parameters.They are accessed through the “use” statement. While the local name of constant may be changed, their values can not be redefined.
Other modules used¶
fms_mod
Public interface¶
use constants_mod [, only: constants_init ]
- constants_init:
A optional initialization routine. The only purpose of this routine is to write the version and tag name information to the log file.
Public data¶
Name |
Type |
Value |
Units |
Description |
---|---|---|---|---|
RADIUS |
real |
6376.e3 |
meters |
radius of the earth |
OMEGA |
real |
7.292e-5 |
1/sec |
rotation rate of the planet (earth) |
GRAV |
real |
9.80 |
m/s2 |
acceleration due to gravity |
RDGAS |
real |
287.04 |
J/kg/deg |
gas constant for dry air |
KAPPA |
real |
2./7. |
RDGAS / CP |
|
CP |
real |
RDGAS/KAPPA |
J/kg/deg |
specific heat capacity of dry air at constant pressure |
RVGAS |
real |
461.50 |
J/Kg/deg |
gas constant for water vapor |
DENS_H2O |
real |
Kg/m3 |
density of liquid water |
|
HLV |
real |
2.500e6 |
J/Kg |
latent heat of evaporation |
HLF |
real |
3.34e5 |
J/kg |
latent heat of fusion |
HLS |
real |
2.834e6 |
J/Kg |
latent heat of sublimation |
TFREEZE |
real |
273.16 |
deg K |
temp where fresh water freezes |
STEFAN |
real |
5.6734e-8 |
(W/m2/deg4 |
Stefan-Boltzmann constant |
VONKARM |
real |
0.40 |
— |
Von Karman constant |
PI |
real |
3.14159265358979323846 |
— |
is it enough? |
Public routines¶
Constants_init
call constants_init
- DESCRIPTION
The only purpose of this routine is to write the version and tag name information to the log file. This routine does not have to be called. If it is called more than once or called from other than the root PE it will return silently. There are no arguments.
Data sets¶
None.
Error messages¶
None.
Loader options¶
None.
Notes¶
<B>NOTES ON USAGE:</B> All constants have been declared as type REAL, PARAMETER. The value a constant can not be changed in a users program. New constants can be defined in terms of values from the constants module using a parameter statement.<br><br> The name given to a particular constant may be changed.<br><br> Constants can be used on the right side on an assignment statement (their value can not be reassigned). <B>EXAMPLES:</B>
use constants_mod, only: TFREEZE, grav_new => GRAV
real, parameter :: grav_inv = 1.0 / grav_new
tempc(:,:,:) = tempk(:,:,:) - TFREEZE
geopotential(:,:) = height(:,:) * grav_new