Sea surface temperature reconstruction for the LGM

The southwest Pacific Ocean covers a broad range of surface-water conditions ranging from warm, salty water in the subtropical East Australian Current to fresher, cold water in the Circumpolar Current. Using a new database of planktonic foraminifera assemblages (AUSMAT-F2), we demonstrate that the modern analog technique can be used to accurately reconstruct the magnitude of sea-surfacetemperature (SST) in this region. We apply this technique to data from 29 deep-sea cores along a meridional transect of the southwest Pacific Ocean to estimate the magnitude of SST cooling during the Last Glacial Maximum. We find minimal cooling in the tropics (0°-2°C), moderate cooling in the subtropical midlatitudes (2°-6°C), and maximum cooling to the southeast of New Zealand (6°-10°C). The magnitude of cooling at the sea surface from the tropics to the temperate latitudes is found to generally be less than cooling at the surface of adjacent land masses.

西南太平洋涵盖了多样的表层水环境，从亚热带东澳洋流中的温暖咸水，到环极流内盐度更低的冷凉水团。本研究依托一套全新的浮游有孔虫（planktonic foraminifera）组合数据库（AUSMAT-F2），证实现代类比法可用于精准重建该区域的海表温度（SST）变化幅度。我们将该方法应用于西南太平洋经向断面上29根深海岩芯的数据，以估算末次冰盛期（Last Glacial Maximum）的海表降温幅度。研究发现，热带区域（0℃~2℃）降温幅度极小，亚热带中纬度区域（2℃~6℃）降温幅度中等，新西兰东南部的降温幅度达到最大（6℃~10℃）。整体来看，从热带到温带纬度的海表降温幅度普遍低于相邻陆块的地表降温幅度。