The Impact of High-/Low SST Resolution in the WRF Model on the Atmospheric Response and Variability in East Asia during the Boreal Winter

Abstract:

The ocean has a large heat capacity compared to atmosphere and it has a potential to influent on atmospheric variability by releasing a latent and sensible heat flux into the atmosphere. To understand the atmosphere variability in response to SST forcing, it is necessary to prescribe a high accuracy and resolution to force an atmosphere model. In this study, we investigate the impact of SST between high/low resolution on atmospheric response in East Asia. We run the two experiments with prescribing different SSTs which have high or low resolution in East Asian region using a WRF model. The result with low-resolution SST run simulates lower SST in most regions near the land than the high-resolution SST run because the SST with high resolution has a characteristic with more transportation of heat energy from the Kuroshio current. The SST difference makes the difference of temperature gradient between land and sea, and then it influence to the other atmospheric components, such as surface pressure, wind pattern, and ascending motion. It is found that the relatively stronger northerly wind in Yellow sea in the high-resolution SST run. And its surface pressure simulates larger value in land than seas around Korea peninsula. It is also found that the different resolution of SST in the WRF model results in different amount of land precipitation. For a reliable interpretation on atmospheric variability in response to SST forcing, it is necessary to prescribe the higher resolution SST in the atmosphere model.