Implications of sea surface temperature deviations in the prediction of wind and precipitable water over the Yellow Sea

The effects of deviations in the sea surface temperature (SST) on the atmospheric variables over the Yellow Sea were investigated by numerical simulations based on realistic deviations in the magnitude and gradient of the SST. The SST magnitude was found to control primarily the surface air temperature, the atmospheric stability, and vertical moisture fluxes, whereas the SST gradient mainly affected the surface wind fields. Although the SST magnitude can also affect wind fields, its effect on the winds was small compared with the influence of the SST gradient. Both the SST gradient and magnitude clearly affected the evaporation rates. The magnitudes of the evaporation rates were found to be directly controlled by the SST magnitude, whereas the horizontal distributions of the evaporation rates were controlled by the SST gradient. The spatial patterns of the precipitable water amounts at the surface were similar to those of the vertical winds but slightly different from those of the evaporation rates. The use of an accurate SST in a meteorological model could be therefore of primary importance particularly for more accurate weather forecasting. Additionally, the effect of deviations in the SST on the atmospheric variables was damping with height, but that on the vertical winds was oscillatory and amplifying to the top of troposphere with height. This study has demonstrated that the construction of realistic SST field without smoothing the SST gradient can produce more accurate and realistic meteorological fields over the Yellow Sea in a mesoscale meteorological model.