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air_dens

PURPOSE ^

AIR_DENS: computes computes the density of moist air.

SYNOPSIS ^

function rhoa=air_dens(Ta,RH,Pa)

DESCRIPTION ^

 AIR_DENS: computes computes the density of moist air.
 rhoa=AIR_DENS(Ta,RH,Pa) computes the density of moist air.
 Air pressure is optional.

 INPUT:   Ta  - air temperature Ta  [C]
          RH  - relative humidity  [%]
          Pa  - air pressure (optional) [mb] 

 OUTPUT:  rhoa - air density  [kg/m^3]

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function  rhoa=air_dens(Ta,RH,Pa)
0002 % AIR_DENS: computes computes the density of moist air.
0003 % rhoa=AIR_DENS(Ta,RH,Pa) computes the density of moist air.
0004 % Air pressure is optional.
0005 %
0006 % INPUT:   Ta  - air temperature Ta  [C]
0007 %          RH  - relative humidity  [%]
0008 %          Pa  - air pressure (optional) [mb]
0009 %
0010 % OUTPUT:  rhoa - air density  [kg/m^3]
0011 
0012 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0013 % 4/7/99: version 1.2 (contributed by AA)
0014 % 8/5/99: version 2.0
0015 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0016 
0017 % load constants
0018 as_consts;
0019 
0020 if nargin == 2
0021   Pa = P_default; 
0022 end
0023 
0024 o61  = 1/eps_air-1;                % 0.61 (moisture correction for temp.)
0025 Q    = (0.01.*RH).*qsat(Ta,Pa);    % specific humidity of air [kg/kg]
0026 T    = Ta+CtoK;                    % convert to K
0027 Tv   = T.*(1 + o61*Q);             % air virtual temperature
0028 rhoa = (100*Pa)./(gas_const_R*Tv); % air density [kg/m^3]
0029

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