Code to calculate (betasw,beta90sw,bsw) as a function of (lambda,Tc,theta,S,delta) where lambda (nm): wavelength Tc: temperauter in degree Celsius, must be a scalar S: salinity, must be scalar delta: depolarization ratio, if not provided, default = 0.039 will be used. betasw: volume scattering at angles defined by theta. Its size is [x y], where x is the number of angles (x = length(theta)) and y is the number of wavelengths in lambda (y = length(lambda)) beta90sw: volume scattering at 90 degree. Its size is [1 y] bw: total scattering coefficient. Its size is [1 y] for backscattering coefficients, divide total scattering by 2