cox_and_munk_u10 valueAt present only available with rte_solver DISORT2. The wind speed is the most important parameter affecting ocean BRDF. The minimum allowed wind speed is 1 m/s because otherwise the strong specular reflection causes numerical problems. If a lower value is specified, the wind speed is automatically set to 1m/s. Also, the number of streams (nstr) is automatically increased to 16 if cox_and_munk BRDF is switched on, to avoid numerical problems. To switch on Cox and Munk BRDF, specify any of the cox_and_munk options and define at least cox_and_munk_u10.