[ \rho_t = \rho_15 \cdot \exp[-\alpha_15(t-15)(1 + 0.8\alpha_15(t-15))] ]

Alcodens-2.1

[ \rho_t = \rho_15 \cdot \exp[-\alpha_15(t-15)(1 + 0.8\alpha_15(t-15))] ]