Wind speed and Latent heat flux derived by Advanced Microwave Scanning Radiometer (AMSR) for Earth Observation Satellite (AMSR-E) are validated using the tropical and the mid-latitude Pacific surface buoys. Obtaining the wind speed and reducing the Relative Wind Direction effect (RWD effect) according to Konda et al.(2006), the root mean square of the error of the wind speed at the mid-latitude buoys is reduced to 1.6 ms^-1, which is slightly worse than that validated by using TAO data in the tropics. The validation shows that the mean error and its tendency are almost same as that of AMSR-E standard product. The combined use of the wind speed and the other AMSR-E products (the sea surface temperature and the integrated water vapor) provides the instantaneous latent heat flux at every observation cells. We show that ambiguity of the estimation of the latent heat flux is caused by traditional way of computation from the boundary layer parameters, each of which is measured by different sun-synchronized satellites. The ambiguity caused by the time-lagged measurement of them is found to amount to -1.3 ± 44.9 Wm^-2. The simultaneous measurement of boundary layer parameters can avoid it and make it possible to directly evaluate the satellite-derived latent heat flux by in situ observation.