*PHY Section

RFM Driver Table Sections: 'Adjustable' Physical Constants

09APR25
Type
Optional Section. No associated flag.

Description
Allows the user to modify certain 'adjustable' physical constants within the RFM associated with the Earth's atmosphere.
Also, the local radius of curvature.

Format
Multiple records, any order, each containing a PARAM=VALUE pair.
PARAM is case insensitive.
Parameter Type Definition Units Default
CPKMOL R Molar heat capacity of air [3] J/(K kmole) 29012.0
GRAVTY R Acceleration due to gravity [4] m/s2 9.80665
RADCRV D Local radius of curvature [5] km 6367.421
TEMSPA R Cosmic background temperature [6] K 2.7
WGTAIR R Molar weight of air [4] kg/kmole 28.964
Type: R=Real; D=Double Precision

Notes
  1. Spaces are allowed before and after PARAM and VALUE fields
  2. The default values for these parameters are stored in phyadj_dat.f90 with names like PARAM_DEF
  3. CPKMOL is only used when calculating cooling rates (COO flag).
  4. GRAVTY and WGTAIR are only used for plane parallel atmospheres (NAD or ZEN flags) without HYD flag.
  5. RADCRV is only used for circular geometry calculations (eg limb-viewing)
  6. TEMSPA is used for radiance calculations which include a space view but, in practice, only affects microwave radiances. However it could also be used to model (crudely) solar background radiance as a hot Black Body.

Example
*PHY RADCRV = 6.4E3 ! modify radius of curvature GRAVTY=9.8 ! modify g

Bugs
[none reported]