def surface_tension_temp(T,a=241.322,b=1.26,c=0.0589,d=0.5,e=0.56917,Tc=647.096):
    
    """ temperature-dependent surface tension calculation
    
    Parameters
    ----------
    T : int array
        diameters array mapped to their indices to generate an array
    a, b, c, d, e : float, optional
        model parameters of sigma parameterization
    Tc : float, optional
        triple point temperature
    
    Returns
    -------
    sigma : float
        surface tension --> returned in SI units
    
    """
    
    """ This function returns the surface tension of water estimated as a
    function of instrument temperature. The empirical relationship between the
    temperature and surface tension has been used as prescribed by
    Kalova and Mares (2018)."""
    
    tau = 1 - T/Tc
    sigma = a*tau**b * (1 - c*tau**d- e*tau)
    
    return sigma*10**-3