The difference between the transferred wind speed to 10-m height based on the equivalent neutral wind approach (U (n)) and the logarithmic approach (U (log)) is studied using in situ observations from the Indian, Pacific, and Atlantic Oceans, with special emphasis given to the North Indian Ocean. The study included U (n) - U (log) variations with pressure, relative humidity, wind speed, air temperature, and sea surface temperature (SST). U (n) - U (log) variation with respect to air temperature (T (a)) reveals that U (n) - U (log) is out of phase with air temperature. Further analysis found that U (n) - U (log) is in phase with SST (T (s)) - T (a) and varies between -1.0 and 1.0 m/s over the North Indian Ocean, while for the rest of the Oceans, it is between -0.3 and 0.8 m/s. This higher magnitude of U (n) - U (log) over the North Indian Ocean is due to the higher range of T (s) - T (a) (-4 to 6 A degrees C) in the North Indian Ocean. Associated physical processes suggested that the roughness length and friction velocity dependence on the air-sea temperature difference contributes to the U (n) - U (log) difference. The study is further extended to evaluate the behavior of U (n) - U (log) under cyclonic conditions (winds between 15 and 30 m/s), and it was found that the magnitude of U-n - U (log) varies 0.5-1.5 m/s under the cyclonic wind conditions. The increasing difference with the wind speed is due to the increase in the momentum transfer coefficient with wind speed, which modifies the friction velocity significantly, resulting in U (n) higher than U (log). Thus, under higher wind conditions, U (n) - U (log) can contribute up to half the retrieval error (5 % of the wind speed magnitude) to the satellite validation exercise.
