Radiation Parameters

Since r1551 an interface for use of radiation models is available in PALM. Currently, PALM offers one built-in radiation model for clear-sky conditions, calculating the net radiation at the surface.

All parts of the radiation code are modularized in module radiation_model_mod. In this context, a new Fortran NAMELIST radiation_par was added, containing all radiation-related steering parameters. The radiation module is automatically activated when a radiation_par is set in the parameter file (_p3d).

NAMELIST group name: radiation_par

Parameter Name	FORTRAN Type	Default Value	Explanation
albedo	R	0.2	Surface albedo (value of 0-1).
day_init	I	172	Day of the year (1-365) at model start. The default value is 172 (June 21).
dt_radiation	R	0.0	Timestep of the radiation model (in s).
lambda	R	0.0	Geographical longitude (in degrees). Note that the radiation scheme also requires information on the geographical latitude (see phi).
net_radiation	R	0.0	Net radiation at the surface in W/m². This parameter is only used in case of radiation scheme= 'constant'.
radiation_scheme	C*10	'clear-sky'	Radiation scheme to be used. The user can choose between the following schemes: 'constant' A constant net radiation at the surface is prescribed (see #net_radiation). 'clear-sky' A simple clear sky model is used to calculate the radiation fluxes at the surface (shortwave incoming, shortwave outgoing, longwave incoming, longwave outgoing) and consequently the net radiation at the surface. This scheme requires setting of albedo, day_init, lambda, phi, and time_utc_init. ( 'rrtm' : not yet implemented.)
time_utc_init	R	43200.0	UTC time at model start in seconds starting from midnight, The default value is 43200.0 (12 p.m., noon).