Comments on the determination of the total heat flux from the sea with a two-wavelength radiometer system as developed by McAlister

Two-wavelength radiometric measurements of heat flux as developed by McAlister require corrections under rough sea conditions. One correction stems from the increase in sea surface area compared with a horizontal plane. Another correction due to sea surface roughness and nadir angle of viewing is required to obtain the temperature gradient normal to the interface. For example, these errors combined amount to 8% for 10-m/sec wind and 20° nadir angle. Vertical advection associated with convergence and divergence due to wave motion and turbulence generally have negligible effect on the two-wavelength radiometric measurement of heat flux but can possibly become significant for capillary waves and strong convection.