Changes in the autumn precipitation and tropical cyclone activity over Central Vietnam and its East Sea

Abstract

Central Vietnam is particularly vulnerable to the impacts of climate change, with all of its incumbent socioeconomic and ecological consequences. This is due in part to the autumn timing of the peak rainfall season in Central Vietnam, at a time when tropical cyclones are most likely to make landfall. We conducted climate diagnostic analyses using meteorological and tropical cyclone data to understand the changing patterns of autumn rainfall and tropical cyclones, revealing an intensification of precipitation over Central Vietnam since the beginning of the 20 th century that is associated with increased tropical cyclones in the adjacent sea. A warming of the sea surface temperature (SST) and enhanced southerly low-level winds are coincident with the above noted increase in rainfall and tropical cyclones. The underlying regional SST and circulation patterns are part of a hemispheric-scale change in the general circulation, i.e. a La Nina-like SST anomaly and a strengthened Walker circulation with the ascending branch located near Vietnam and far-western Pacific. We make the case with this paper that increasing autumn rainfall and tropical cyclones should be taken into account any mitigation and adaptation plans anticipated for Central Vietnam.