\mu_w(T, p) = 0.001 \cdot \mu_{w0}(T, p) \cdot \mu_r(T, m)

\ln \mu_{w0}(T, p) = \sum_{n = 1}^5 \, d_n \cdot T^{n-3} + \rho_w(T, p) \cdot \sum_{n = 6}^{10} \, d_n \, T^{n-8}

\ln \mu_r(T, m) = A \cdot m + B \cdot m^2 + C \cdot m^3

 A = a_0 + a_1 \, T + a_2 \, T^2

 B = b_0 + b_1 \, T + b_2 \, T^2

 C = c_0 + c_1 \, T 

 m = \frac{1,000 \cdot S}{M_{\mbox{NaCl}} \cdot (1-S)}