High resolution reconstruction of hydrological cycle in the East Asia during the last deglaciation using terrestrial biomarkers

本研究旨在通过重建末次冰川消融期间东亚边缘降水的纬度梯度，来研究厄尔尼诺-南方涛动在末次消冰期变暖和水文变化中的作用。为此，我们分析了热带到亚北极地区五个不同位置的海洋岩心中的陆地生物标志物。木质素、陆地生物标志物和花粉成分以及生物标志物特有的氢/氢比的变化表明，北纬30度以北的地区气候干燥，北纬8度的地区在最后一次冰川消融期间降水增加。这种降水的纬向梯度增强可能是北太平洋类似厄尔尼诺大气模式和热带对流加强的共同作用。冬季阿留申低压在最近两次冰川消融期间加强。在最后一次冰川消融期间，冬季风较强。在日本边缘的海表面温度记录中发现了全新世1500年的振荡。

This study aims at examining the role of El Nino-Southern Oscillation in last deglacial warming and hydrological changes by reconstructing the latitudinal gradient of precipitation along the East Asian margin during the last deglaciation. For this purpose, we analyzed terrestrial biomarkers in marine cores from five different locations from the tropical to subarctic regions.Variations in lignin, terrestrial biomarkers and pollen compositions and biomarker-specific deuterium/hydrogen ratio indicated a dry climate in the regions north of 30 degrees north and an increase of precipitation at the site of 8 degrees north during the last deglaciation. This enhanced latitudinal gradient of precipitation was presumably caused by the combination of El Nino-like atmospheric pattern in the North Pacific and the intensified tropical convection.Other findings are as follows. The winter Aleutian Low was intensified during the last two deglaciations. Winter monsoon was stronger during the last deglaciation. The Holocene 1500-year oscillation was found in the sea surface temperature record from the Japan margin.