function writelwn(outFilename, eu, crd, cfl, Lw, Es, Lu, lambda, lat, lon)

% Brian Schlining
% 01 Feb 2000

fid = fopen(outFilename, 'wt');				         % Open the output file for writing
if fid < 1
   error(['Unable to open file ' outFilename]);
end

if nargin < 10
   
   lat = [];
   lon = [];
   while isempty(lat)
      fprintf(1, '\n************************************************\n');
      fprintf(1, 'Enter latitude of cast in decimal degrees (+N/-S).\n');
      latS = input('Enter NaN if the latitude is unknown:   ', 's');
      
      lat = str2num(latS);
   end
   if isnan(lat)
      latS = '-999';
      lon = NaN;
   end
   
   
   while isempty(lon)
      fprintf(1, '\n************************************************\n');
      fprintf(1, 'Enter longitude of cast in decimal degrees (+E/-W).\n');
      lonS = input('Enter NaN if the longitude is unknown:   ', 's');
      lon = str2num(lonS);
   end
   if isnan(lon)
      lonS = '-999';
   end 
   
   fprintf(1, '************************************************\n\n');
end

%==========================
% Begin writing the header
%==========================
fprintf(fid, '/begin_header\n');
fprintf(fid, '/affiliations=Monterey_Bay_Aquarium_Research_Institute\n');
fprintf(fid, '/investigators=%s\n', crd.operatorName);
fprintf(fid, '/experiment=%s\n', crd.cruiseId);
fprintf(fid, '/cruise=%s\n', crd.cruiseId);
fprintf(fid, '/contact=%s\n', 'www.mbari.org');
fprintf(fid, '/paramters=Lu,Ed,Lw,Kd\n');
[p outfile ext] = fileparts(outFilename);
fprintf(fid, '/data_file_name=%s\n', [outfile ext]);
[p filename ext] = fileparts(crd.src);
fprintf(fid, '/original_file_name=%s.bin\n', filename);
fprintf(fid, '/data_type=profile\n');
fprintf(fid, '/documents= N/A\n');
fprintf(fid, '/west_longitude=%s[DEG]\n', lonS);
fprintf(fid, '/east_longitude=%s[DEG]\n', lonS);
fprintf(fid, '/north_latitude=%s[DEG]\n', latS);
fprintf(fid, '/south_latitude=%s[DEG]\n', latS);
fprintf(fid, '/delimiter=space\n');
[yearMin monthMin dayMin hourMin minuteMin secondMin] = datevec(crd.firstTime);
secondMin = round(secondMin);
[yearMax monthMax dayMax hourMax minuteMax secondMax] = datevec(crd.endTime);
secondMax = round(secondMax);
fprintf(fid, '/start_date=%04i%02i%02i\n', yearMin, monthMin, dayMin);
fprintf(fid, '/end_date=%04i%02i%02i\n', yearMax, monthMax, dayMax);
fprintf(fid, '/start_time=%02i:%02i:%02i[GMT]\n', hourMin, minuteMin, secondMin);
fprintf(fid, '/end_time=%02i:%02i:%02i[GMT]\n', hourMax, minuteMax, secondMax);
fprintf(fid, '/calibration_files=%s%s,%s\n', filename, ext, cfl.src);
fprintf(fid, '/station=%s\n', crd.location);
fprintf(fid, '/missing=-999\n');
fprintf(fid, '! Comments: Lw is calculated by fitting the equation, y =  c(1)*exp(-a(1)*z) + c(2)*exp(-a(2)*z) + c(3), to the Lu data.\n');
fprintf(fid, '! Comments: Rrs is calculated as Lw/Es\n');
fprintf(fid, '! Comments: Location: %s\n', crd.location);
fprintf(fid,'/fields=wavelength,Ed(0-),Es,Lu(0-),Lw,Lwn,Rrs\n');
fprintf(fid,'/units=nm,uW/cm^2/nm,uW/cm^2/nm,uW/cm^2/nm/sr,uW/cm^2/nm/sr,uW/cm^2/nm/sr,1/sr\n');
fprintf(fid,'/end_header@\n');
channels = strvcat(cfl.info.description);
bad = strmatch( 'PAR', channels(Es,:));
Es(find(Es == max(bad))) = [];
EsLambda = [];
for i = 1:length(Es)
   EsLambda = [EsLambda str2num(channels(Es(i),3:end))'];
end

LuLambda = str2num(channels(Lu,3:end))';
uLambda  = unique([EsLambda LuLambda]);

Es0 = nanmean(eu(:,Es));
Lu0_ = Lw./0.544;
if ~strcmp(latS, '-999') | ~strcmp(lonS, '-999')
   pctTrans = 1 - fresnel_(solarzenith(crd.firstTime, lat, lon));
   Fn       = calc_fn(crd.firstTime, lat, lon, LuLambda);
   Es0_     = Es0.*pctTrans;
   Lwn      = Lw./Fn;
else
   Es0_ = ones(size(Es0))*-999;
   Lwn = ones(size(Lw))*-999;
end

for i = 1:length(uLambda)
   goodEs = find(EsLambda == uLambda(i));
   goodLu = find(LuLambda == uLambda(i));
   if ~isempty(goodEs)
      ES0  = Es0(goodEs);
      ES0_ = Es0_(goodEs);
   else
      ES0  = -999;
      ES0_ = -999;
   end
   
   if ~isempty(goodLu)
      LW   = Lw(goodLu);
      LU0_ = Lu0_(goodLu);
      LWN  = Lwn(goodLu);
   else
      LW   = -999;
      LU0_ = -999;
      LWN  = -999;
   end
   
   if ~isempty(goodLu) & ~isempty(goodEs)
      Rrs = LW/ES0;
   else
      Rrs = -999;
   end
   
   
   fprintf(fid, '%12.6f ', uLambda(i));
   fprintf(fid, '%12.6f %12.6f %12.6f %12.6f %12.6f %12.6f\n', ES0_, ES0, LU0_, LW, LWN, Rrs);
end


fclose(fid);