Orbital-scale vegetation-ocean-atmosphere linkages in western Japan during the last 550 ka based on a pollen record from the IODP site U1427 in the Japan Sea
Orbital-scale vegetation-ocean-atmosphere linkages in western Japan during the last 550 ka based on a pollen record from the IODP site U1427 in the Japan Sea
复制标题
DOI：
10.1016/j.quascirev.2021.107103
复制
发表时间：
2021-09
影响因子：
4
通讯作者：
Ryoma Hayashi;T. Sagawa;T. Irino;R. Tada
中科院分区：
文献类型：
--
作者：
Ryoma Hayashi;T. Sagawa;T. Irino;R. Tada
日本的气候和植被深受东亚季风（EAM）和日本海海洋环境的影响。这项研究讨论了位于日本西部本州岛北海岸附近的综合海洋钻探计划站点 U1427 的新花粉记录的发现，该记录可以与该地区的其他海洋学代理进行直接比较。我们的研究结果证明了过去 550ka 期间该地区轨道尺度植被的变化及其陆地-海洋-大气的联系。在日本海的地表水淡化事件期间，可能与极低的海平面升降导致的水温降低以及随后在全冰期期间与周围海洋的隔离有关，在日本列岛极其干燥的伪大陆条件下，寒冷的针叶林成为主导。相比之下，除了终止期间大气气候迅速变暖之外，当地表清新事件结束、冰川消融开始时温水开始微弱流入时，温带阔叶林迅速增加。在全间冰期到全冰期的中间时期，Tp比值（花粉温度指数）随着地球进动周期引起的夏季日照最大值的增加而增加，这与中国石笋负δ18O峰一致，而隐花花粉丰度（高降水指数）则随着冬季日照最大值的增加而增加。这些轨道尺度的植被波动归因于季节性温度和降水模式的变化，而这些变化又受到与日本列岛周围季节性日照变化相关的EAM变化的影响。柳杉森林很可能在全年凉爽湿润的条件下生长，季节性对比较低，而落叶阔叶林则在夏季凉爽、冬季寒冷干燥的高季节性条件下增加。通常在 MIS 9 之后观察到日照变化后 Tp 比率和隐花粉丰度之间的交替波动，并且被认为受到了中布伦赫斯事件中 EAM 波动周期性变化的影响。
Climate and vegetation in Japan are strongly influenced by the East Asian Monsoon (EAM) and the ocean environment of the Japan Sea. This study discusses the findings from a new pollen record from Integrated Ocean Drilling Program Site U1427, situated off the northern coast of the Honshu Island in western Japan, which allows for direct comparisons with other oceanographic proxies from this area. Our findings demonstrate the orbital-scale vegetation changes in this area and their land-ocean-atmosphere linkages during the last 550 ka. During surface-water freshening events in the Japan Sea, likely associated with colder water temperatures caused by the very low eustatic sea levels and the consequent isolation from the surrounding seas during the full-glacial periods, cold-cool conifer forests became dominant under the extremely dry pseudo-continental conditions in the Japanese islands. In contrast, temperate broadleaf forests increased rapidly when the surface-freshening events ended and a weak inflow of warm water began at the onset of deglaciation, in addition to the rapid atmospheric climate warming during termination periods. During the intermediate periods between the full interglacial to the full-glacial, the Tp ratio (pollen temperature index) increased in association with the summer insolation maxima caused by the Earth's precession cycle that coincide with Chinese stalagmite negative δ18O peaks, whereasCryptomeriapollen abundance (high-precipitation index) increased in association with the winter insolation maxima. Those orbital-scale vegetation fluctuations were attributed to the changes in seasonal temperature and precipitation patterns, where were influenced by the EAM changes that were associated with seasonal insolation changes around the Japanese archipelago.Cryptomeriaforests likely developed under cool and wet conditions throughout a year with low seasonal contrasts, whereas deciduous broadleaf forests increased under condition of high seasonality with cool summers and colder, drier winters. Alternating fluctuations between the Tp ratio andCryptomeriapollen abundance following the insolation changes were typically observed after MIS 9 and are thought to have been affected by the periodicity shift in the EAM fluctuations across the Mid-Brunhes Event.