Search

This study investigates the roles of water vapor transport and sea surface temperature (SST) warming in the tropical Indian Ocean (TIO) on the heavy rainfall in central China during the boreal early summer (May–June–July). In the past four decades, four significant rainfall events, in 1983, 1998, 2016, and 2020, occurred in central China and caused severe floods, and the year 2020 has the most extreme event. All four events are associated with significant TIO SST warming and a strong anomalous anticyclone on the western North Pacific (WNPAC). The anomalous winds in the northwestern flank of the WNPAC bring excess water vapor into central China. The water vapor, mainly carried from the western tropical Pacific, converges in central China and result in heavy rainfall. A theory of regional ocean–atmosphere interaction can well explain the processes, called the Indo-Western Pacific Ocean Capacitor (IPOC) effect. The WNPAC is usually associated with strong El Niño-Southern Oscillation (ENSO), except for the 2020 case. The 2020 event is extraordinary without a significant El Niño occurred in the previous winter. In 2020, the significant TIO warming sustained the anomalous WNPAC, inducing the most significant extreme rainfall event in central China. This study reveals that the IPOC effect can dramatically influence the East Asian climate even without involving the ENSO in the Pacific. [ABSTRACT FROM AUTHOR]

This study examines the climate response to a sea surface temperature (SST) warming imposed over the southwest tropical Indian Ocean (TIO) in a coupled ocean–atmosphere model. The results indicate that the southwest TIO SST warming can remotely modulate the atmospheric circulation over the western North Pacific Ocean (WNP) via interbasin air–sea interaction during early boreal summer. The southwest TIO SST warming induces a "C shaped" wind response with northeasterly and northwesterly anomalies over the north and south TIO, respectively. The northeasterly wind anomalies contribute to the north TIO SST warming via a positive wind–evaporation–SST (WES) feedback after the Asian summer monsoon onset. In June, the easterly wind response extends into the WNP, inducing an SST cooling by WES feedback on the background trade winds. Both the north TIO SST warming and the WNP SST cooling contribute to an anomalous anticyclonic circulation (AAC) over the WNP. The north TIO SST warming, WNP SST cooling, and AAC constitute an interbasin coupled mode called the Indo-western Pacific Ocean capacitor (IPOC), and the southwest TIO SST warming could be a trigger for IPOC. While the summertime southwest TIO SST warming is often associated with antecedent El Niño, the warming in 2020 seems to be related to extreme Indian Ocean dipole during the autumn of 2019. The strong southwest TIO SST warming seems to partly explain the strong summer AAC of 2020 over the WNP even without a strong antecedent El Niño. [ABSTRACT FROM AUTHOR]

The Indo-Pacific Convergence Zone (IPCZ) has a complex ocean dynamical system. All scale processes are active and interplay from small-scale turbulent mixing to basin-scale circulation. The IPCZ acts as an "oceanic bridge" for the inter-basin mass transports and basin-scale planetary waves, closely linking basin-scale circulations in the Pacific and Indian Oceans. Numerous straits in the Indonesian Seas provide oceanic channels for planetary waves propagating between the tropical Pacific and the southeast Indian Ocean. On a large scale, the inter-basin mass transports and planetary waves change the ocean thermal structure, triggering strong air-sea interactions, and further regulating the variability of Walker and Hadley Circulations. The latter form an "atmospheric bridge", which significantly affects the Asian and Australian monsoon systems and a series of global climate events like El Niño-Southern Oscillation (ENSO), Indian Ocean Dipole, and Indian Ocean Basinwide warming. On meso- and small- scales, eddy, submesoscale processes, and turbulent motions mix the water mass from different sources, dramatically stirring the upper ocean in the IPCZ. Ocean dynamics have essential impacts on the ecological system in the IPCZ. On the one hand, these processes directly affect biodiversity by controlling the genetic exchanges and species dispersals between basins. On the other hand, the ocean dynamical processes influence biogeochemical cycling by controlling the trophic transfer, which further impacts primary productivity. With the intensified climate variations under global warming, e.g., marine heatwaves and extreme events, the ocean dynamical processes turn more active and enhance the influence on the ecosystem. This work overviews a series of studies focusing on the multi-scale ocean dynamical and environmental processes in the IPCZ, including the climatic signatures in coral records and the ecological response. [ABSTRACT FROM AUTHOR]