末次冰盛期以来鄂霍次克海北部陆架的海冰变化

本文通过高分辨率粒度分析,研究了鄂霍次克海北部陆架LV87-54-1岩芯记录的海冰活动历史。利用AnalySize程序对粒度数据进行端元分析,提取了3个端元,并将EM3作为海冰指标。EM3含量结果表明,末次冰盛期以来鄂霍次克海北部陆架以活动性海冰覆盖为主。末次冰盛期和海因里希冰阶1期（HS 1）时EM3含量最高,指示海冰活动强烈。冰期时北半球中高纬度气候变冷与北极涛动负相位是导致海冰大规模扩张的主要控制机制,东亚夏季风减弱与黑龙江入海径流量的减少促使鄂霍次克海生成更多的海冰。自波令−阿勒罗德间冰阶开始以来,鄂霍次克海北部陆架海冰生成急剧减少,在新仙女木时期海冰曾出现微弱峰值,随后又快速下降。自全新世以来,受北半球中高纬度气候变暖、秋季太阳辐射量升高、北极涛动正相位和东亚夏季风的增强共同影响,EM3含量一直稳定在较低水平,鄂霍次克海海冰的生成受到明显抑制。

Sea ice variations in the northern Okhotsk Sea shelf since the Last Glacial Maximum

Here we examine the history of sea ice activity recorded in the Core LV87-54-1 recovered from the northern Okhotsk Sea shelf using high-resolution grain-size analyses. We extracted 3 end members and use EM3 as the sea-ice proxy, using the program AnalySize to conduct end members analyses on the data. According to EM3 results, active sea ice was persistently predominant in the northern Okhotsk Sea shelf since the Last Glacial Maximum. The EM3 content was high and the sea ice activity was intense during the Last Glacial Maximum and Heinrich Stadial 1. The climate cooling at the middle and high latitudes of the Northern Hemisphere and the negative Arctic Oscillation were the main controlling mechanism for sea ice expansion during glacial periods. And weakened runoff from the Amur caused by decreased East Asian Summer Monsoon would allow more sea ice formation in the Okhotsk Sea. Sea ice formation decreased at the onset of the Bølling-Allerød warm period, and then decreased sharply after a slight peak during the Younger Dryas Event. EM3 levels remained low stably since the Holocene due to: increased local autumn insolation, positive Arctic Oscillation and enhanced East Asian Summer Monsoon suppresses subsequent sea ice formation.