satvap

 SATVAP: computes saturation vapor pressure
 q=satvap(Ta) computes the vapor pressure at satuation at air 
 temperature Ta (deg C). From Gill (1982), Atmos-Ocean Dynamics, 606.

    INPUT:   Ta- air temperature  [C]
             p - pressure (optional)  [mb]

    OUTPUT:  q  - saturation vapour pressure  [mb]

0001 function ew=satvap(Ta,P)
0002 % SATVAP: computes saturation vapor pressure
0003 % q=satvap(Ta) computes the vapor pressure at satuation at air
0004 % temperature Ta (deg C). From Gill (1982), Atmos-Ocean Dynamics, 606.
0005 %
0006 %    INPUT:   Ta- air temperature  [C]
0007 %             p - pressure (optional)  [mb]
0008 %
0009 %    OUTPUT:  q  - saturation vapour pressure  [mb]
0010 
0011 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0012 % 3/8/97: version 1.0
0013 % 8/27/98: version 1.1 (corrected by RP)
0014 % 8/5/99: version 2.0
0015 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0016 
0017 as_consts;
0018 
0019 if nargin<2,
0020   P=P_default;
0021 end;
0022 if nargin==0,
0023   Ta=Ta_default;
0024 end;
0025 
0026 ew=power(10,((0.7859+0.03477*Ta)./(1+0.00412*Ta)));
0027 
0028 fw=1 + 1e-6*P.*(4.5+0.0006*Ta.^2);
0029 
0030 ew=fw.*ew;