Spatial gradients of temperature, accumulation and δ18O-ice in Greenland over a series of Dansgaard-Oeschger events
Spatial gradients of temperature, accumulation and δ18O-ice in Greenland over a series of Dansgaard-Oeschger events
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DOI：
10.5194/cp-9-1029-2013
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发表时间：
2013-01-01
影响因子：
4.3
通讯作者：
Vinther, B. M.
中科院分区：
文献类型：
--
作者：
Guillevic, M.;Bazin, L.;Vinther, B. M.
对格陵兰岛四个深冰芯（GRIP、GISP2、NGRIP 和 NEEM）的空气和水稳定同位素测量进行了一系列 Dansgaard Oeschger 事件（DO 8、9 和 10）的研究，这些事件代表了冰川千年尺度的变化。结合 firn 建模，空气同位素数据使我们能够量化每个钻探地点的温度突然升高（NEEM、GRIP 和 GISP2 为 1 西格玛 = 0.6 摄氏度，NGRIP 为 1.5 摄氏度）。我们的数据显示，格陵兰岛中部和北部的场间温度升高幅度比格陵兰岛西北部高出 2 摄氏度：即，对于 DO 8，推断出 +8.8 摄氏度的幅度，这明显小于 GISP2 推断的 +11.1 摄氏度。积累增加也存在相同的空间模式。这种模式与针对北欧海域海冰范围减少的气候模拟是一致的。时间水同位素 (delta O-18) 温度温度关系在 0.3 和 0.6 (+/- 0.08) %℃-1 之间变化，并且在 NEEM 系统上更大，可能是由于与 GISP2、GRIP 或 NGRIP 相比，降水季节性变化有限。仅当假设累积量比 Dansgaard Johnsen 冰流模型低 26% (NGRIP) 至 40% (GRIP) 时，才能对以水和空气同位素表示的变暖事件的气体年龄冰龄差异进行建模。
Air and water stable isotope measurements from four Greenland deep ice cores (GRIP, GISP2, NGRIP and NEEM) are investigated over a series of Dansgaard Oeschger events (DO 8, 9 and 10), which are representative of glacial millennial scale variability. Combined with firn modeling, air isotope data allow us to quantify abrupt temperature increases for each drill site (1 sigma = 0.6 degrees C for NEEM, GRIP and GISP2, 1.5 degrees C for NGRIP). Our data show that the magnitude of stadial interstadial temperature increase is up to 2 degrees C larger in central and North Greenland than in northwest Greenland: i.e., for DO 8, a magnitude of +8.8 degrees C is inferred, which is significantly smaller than the +11.1 degrees C inferred at GISP2. The same spatial pattern is seen for accumulation increases. This pattern is coherent with climate simulations in response to reduced sea-ice extent in the Nordic seas. The temporal water isotope (delta O-18) temperature temperature relationship varies between 0.3 and 0.6 (+/- 0.08) %degrees C-1 and is systematically larger at NEEM, possibly due to limited changes in precipitation seasonality compared to GISP2, GRIP or NGRIP. The gas age ice age difference of warming events represented in water and air isotopes can only be modeled when assuming a 26 % (NGRIP) to 40 % (GRIP) lower accumulation than that derived from a Dansgaard Johnsen ice flow model.