Water Exchange between the Western Equatorial Pacific Ocean and the South China Sea using coral geochemistry and ROMS

Nathalie Goodkin, Nanyang Technological University, Singapore, Singapore; American Museum of Natural History, New York, NY, United States, Dhrubajyoti Samanta, Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore, Riovie Dela Pena Ramos, William Paterson University, Department of Environmental Science, Wayne, United States and Kristopher B Karnauskas, University of Colorado Boulder, Boulder, United States
Abstract:
Water transport into the South China Sea (SCS) via the Luzon Strait (LS) is important for ocean heat transport and East Asian climate, but our knowledge of its variability through time is still limited. Two hundred years of coral geochemistry data from the Luzon Strait show varying influences on sea surface temperature (SST), sea surface salinity (SSS) and sea water exchange through the LS with the Pacific Decadal Oscillation (PDO), El Nino Southern Oscillation (ENSO) and the East Asian Winter Monsoon (EAWM) closely linked to variability of different processes at varying time-scales. ENSO is shown to most influence the flow into the SCS while a weak EAWM slows the flow. While the PDO accounts for most of the SST and SSS variability on the southern end of the LS, the northern end of the LS reflects larger scale hemispheric processes. Here using a set of idealized regional model experiments, we simulate the impact of SST anomalies over the western equatorial Pacific Ocean on the SCS upper ocean to investigate the results of the coral geochemical data. First, using a regional atmospheric model (WRF), we carried out two simulations over the tropical Indo-Pacific at 30 km horizontal resolution corresponding to positive and negative SST anomaly patterns over the western equatorial Pacific Ocean. Further, we conducted two Regional Ocean Model (ROMS) experiments over the SCS (20 km resolution) to characterize the impact of anomalous atmospheric patterns corresponding to positive and negative western equatorial Pacific SST anomalies obtained from WRF simulations. The seasonal behaviour of upper ocean dynamics, with a focus on winter monsoon variability, and heat and water transport through the Luzon strait is analysed. Our results provide a mechanistic understanding of regional teleconnections between the western equatorial Pacific Ocean and the SCS. It also provides insights into paleoclimate records derived from the SCS and into East Asian climate variability.
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