The model is essentially the same model as used for internal convection, but the conductance of convection is here not a constant, but rather a function of the wind velocity.
The wind velocity is retrieved from a large lookup table.
Parameters: ac: Cover area of Biosphere (default value = 5667.0 m2) hai: Convection coefficient equation intercept (default value = 39.6 kJ/(h.m2.K)) hai2: Convection coefficient equation slope (default value = 0.0034 kJ/(m3.K)) ucx: Cover normal specific thermal conductance adjustment factor (default value = 1) ucp: Cover normal specific thermal conductance (default value = 72 kJ/(h.m2.K)) R2: Specific resistance due to conduction (default value = 1/(ucx*ucp) h.m2.K/kJ)