Atmospheric response to interannual variability of sea surface temperature front in the East China Sea in early summer

The atmospheric response, especially the response of the meiyu-baiu rainband, to interannual variability of the sea surface temperature (SST) front associated with the Kuroshio in the East China Sea in early summer is examined by using reanalysis, satellite, and rain-gauge datasets from 1982 to 2010. It is revealed that the strong (weak) SST front in the East China Sea is accompanied by the heavy (weak) precipitation over the central East China Sea and the southern Japan. Because the strong SST front largely results from the negative SST anomaly over the continental shelf, the local evaporation change in the East China Sea is not balanced by this enhanced precipitation. The moisture for this enhanced precipitation is supplied by interannual variability of horizontal wind convergence over the central East China Sea. In addition to the precipitation change, the strong SST front is also accompanied by the intensification of weather disturbances in the lower troposphere over the East China Sea. This is probably because the negative SST anomaly over the continental shelf enhances the baroclinicity in the lower troposphere. This intensification of the weather disturbances over the East China Sea can explain the enhanced precipitation over the central East China Sea in response to the interannual variability of the SST front. Because the SST anomaly over the continental shelf, which primarily determines the interannual variability of the SST front, persists for a couple of months, these results imply the predictability of the precipitation associated with the meiyu-baiu rainband.