function alb=albedo(trans,sunalt)

% ALBEDO: computes sea surface albedo following Payne (1972).

% alb=ALBEDO(trans,sunalt) computes the sea surface albedo from the

% atmospheric transmittance and sun altitude by linear interpolation 

% using Table 1 in Payne (1972), J. Atm. Sci., 29, 959-970. Assumes 

% trans and sunalt both matrices of same size. Table 1 is called 

% albedot1.mat.

%

% INPUT:   trans - atmospheric transmittance 

%          sunalt - sun altitude [deg] 

% 

% OUTPUT:  alb - albedo 



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% 3/10/96: version 1.0

% 7/24/98: version 1.1 (rev. to handle out-of-range input values by RP)

% 8/5/99:  version 2.0

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% load table 1 

load albedot1



% create axes

x=[0:2:90];

y=[0:.05:1.0]';



alb=ones(size(trans))+NaN;

k=sunalt>0 & finite(trans) & trans<=1.01;



% interpolate

alb(k)=interp2(x,y,albedot1,sunalt(k),trans(k));