Sensitivity of Extreme Rainfall in Taiwan to SST Over the South China Sea Through Modulation of Marine Boundary Layer Jet: A Mei-Yu Front Event During 1–4 June 2017

Water vapor transport from the South China Sea (SCS) by the marine boundary layer jet (MBLJ) can be an important moisture source for heavy rainfall events in Taiwan during the mei-yu season. However, the variability in the MBLJ due to sea surface temperature (SST) changes and its impact on extreme rainfall events have yet to be well understood. This study investigates how varying the SST over SCS modifies the structure of MBLJ and further impacts an extreme mei-yu rainfall in Taiwan during 1–4 June 2017. Results show that SST over the SCS can affect rainfall in Taiwan through its modulation of the MBLJ. Increasing SST leads to a southward shift of the mei-yu rainfall. This is attributed to the weakening of the MBLJ and the enhanced convection at the leading edge of the mei-yu front. The opposite effect is observed when the SST is decreased but with a smaller impact.