资源环境科技发展态势分析平台

Seasonal surface freshening of the Makassar Strait, the main conduit of the Indonesian Throughflow (ITF), is a key factor controlling the ITF. Here we present a 262year reconstruction of seasonal sea-surface-salinity variability from 1742 to 2004 Common Era by using coral O-18 records from the central Makassar Strait. Our record reveals persistent seasonal freshening and also years with significant truncations of seasonal freshening that correlate exactly with South Pacific Convergence Zone (SPCZ) zonal events >4000km to the east. During these events, the SPCZ dramatically rotates similar to 15 degrees north to near the equator and stronger westward flowing South Pacific boundary currents force higher-salinity water through the Makassar Strait in February-May halting the normal seasonal freshening in the strait. By these teleconnections, our Makassar coral O-18 series provides the first record of the recurrence interval of these zonal SPCZ events and demonstrates that they have occurred on a semiregular basis since the mid-1700s.