function T = tropcorr(El)

	% Return an estimate of T based solely on elevation
	% Uses "standard atmosphere" values for temp., pressure, and
	% relative humidity
    
    El = El/180*pi;
	T = 2.312 ./ sin(sqrt(El .* El + 1.904e-3)) + ...
               0.084 ./ sin(sqrt(El .* El + 0.6854e-3));

return