Roosevelt Island Climate Evolution (RICE) ice core isotope record

High-resolution, well-dated climate archives provide an opportunity to investigate the dynamic interactions of climate patterns relevant for future projections. Here, we present data from a new, annually-dated ice core record from the eastern Ross Sea. Comparison of the Roosevelt Island Climate Evolution (RICE) ice core records with climate reanalysis data for the 1979-2012 calibration period shows that RICE records reliably capture temperature and snow precipitation variability of the region. RICE is compared with data from West Antarctica (West Antarctic Ice Sheet Divide Ice Core) and the western (Talos Dome) and eastern (Siple Dome) Ross Sea. For most of the past 2,700 years, the eastern Ross Sea was warming with perhaps increased snow accumulation and decreased sea ice extent. However, West Antarctica cooled whereas the western Ross Sea showed no significant temperature trend. From the 17th Century onwards, this relationship changes. All three regions now show signs of warming, with snow accumulation declining in West Antarctica and the eastern Ross Sea, but increasing in the western Ross Sea. Analysis of decadal to centennial-scale climate variability superimposed on the longer term trend reveal that periods characterised by opposing temperature trends between the Eastern and Western Ross Sea have occurred since the 3rd Century but are masked by longer-term trends. This pattern here is referred to as the Ross Sea Dipole, caused by a sensitive response of the region to dynamic interactions of the Southern Annual Mode and tropical forcings.

高分辨率、定年精准的气候档案，为探究与未来气候预测相关的气候模态动态相互作用提供了关键契机。本研究发布了一份采自罗斯海东部分区的全新年定年冰芯记录数据。将罗斯福岛气候演化（Roosevelt Island Climate Evolution, RICE）冰芯记录与1979-2012年校准期的气候再分析数据对比后发现，RICE记录能够可靠捕捉该区域的温度与降雪量变化特征。本研究还将RICE记录与西南极洲（西南极冰盖分冰芯）、罗斯海西部（泰勒穹顶）及罗斯海东部（西普尔穹顶）的相关数据进行了对比分析。在过去2700年的大部分时段内，罗斯海东部分区持续变暖，降雪量或有所增加，海冰范围则呈缩减趋势。但与之相对，西南极洲出现降温态势，罗斯海西部则未呈现显著的温度变化倾向。自17世纪起，这种区域气候响应关系发生了改变。当前三个区域均显现变暖迹象：西南极洲与罗斯海东部分区的降雪量有所减少，而罗斯海西部的降雪量则呈上升趋势。通过对叠加于长期趋势之上的十年至百年尺度气候变率开展分析，研究发现：自公元3世纪以来，罗斯海东西部曾多次出现温度趋势相反的时段，但此类信号长期被更长尺度的气候趋势所掩盖。这种区域气候模态被命名为“罗斯海偶极子”，其成因是该区域对南方年度模态（Southern Annual Mode）与热带强迫的动态相互作用存在敏感响应。