lwhf

 LWHF: computes net longwave heat flux following Dickey et al (1994).
 qlw=LWHF(Ts,dlw) computes the net longwave heat flux into the ocean.
 Following Dickey et al (1994), J. Atmos. Oceanic Tech., 11, 1057-1078,
 the incident longwave flux can be corrected for sensor heating due to
 insolation if you are using Epply or Kipp & Zonen CG1 pyrgeometers.
 In this case, use qlw=LWHF(Ts,dlw,dsw). Epply is the default 
 pyrgeometer; change code for the Kipp & Zonen instrument.

   INPUT:  Ts  - sea surface temperature [C]
           dlw - (measured) downward longwave flux [W/m^2]
           dsw - (measured) insolation [W/m^2] (needed for Eppley 
                 or Kipp & Zonen pyrgeometers)

   OUTPUT: qlw - net longwave heat flux [W/m^2]

0001 function qlw=lwhf(Ts,dlw,dsw)
0002 % LWHF: computes net longwave heat flux following Dickey et al (1994).
0003 % qlw=LWHF(Ts,dlw) computes the net longwave heat flux into the ocean.
0004 % Following Dickey et al (1994), J. Atmos. Oceanic Tech., 11, 1057-1078,
0005 % the incident longwave flux can be corrected for sensor heating due to
0006 % insolation if you are using Epply or Kipp & Zonen CG1 pyrgeometers.
0007 % In this case, use qlw=LWHF(Ts,dlw,dsw). Epply is the default
0008 % pyrgeometer; change code for the Kipp & Zonen instrument.
0009 %
0010 %   INPUT:  Ts  - sea surface temperature [C]
0011 %           dlw - (measured) downward longwave flux [W/m^2]
0012 %           dsw - (measured) insolation [W/m^2] (needed for Eppley
0013 %                 or Kipp & Zonen pyrgeometers)
0014 %
0015 %   OUTPUT: qlw - net longwave heat flux [W/m^2]
0016 
0017 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0018 % 3/8/97: version 1.0
0019 % 8/19/98: version 1.1 (revised for non-Epply pyrgeometers by RP)
0020 % 4/9/99: version 1.2 (included Kipp & Zonen CG1 pyrgeometers by AA)
0021 % 8/5/99: version 2.0
0022 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0023 
0024 % get constants
0025 as_consts;
0026 
0027 % convert degC to degK
0028 ts=Ts+CtoK;
0029 
0030 % correct dlw for sensor heating by insolation
0031 if nargin==3,
0032   % this line is for Epply pyrgeometers
0033   dlwc=dlw-0.036.*dsw; 
0034 
0035   % this line is for Kipp & Zonen CG1 pyrgeometers
0036   % (the offset is specified as 25 W/m^2 at 1000 W/m^2)
0037   % dlwc=dlw-0.025.*dsw;
0038 else
0039   dlwc=dlw;
0040 end;
0041 
0042 % compute upward gray-body longwave flux
0043 lwup=-emiss_lw.*sigmaSB.*(ts.^4);
0044 
0045 % compute net flux
0046 qlw=lwup + emiss_lw.*dlwc;
0047