来自玻利维亚冰芯的25,000年热带气候历史
Thompson1, Davis, Mosley-Thompson
1L. G. Thompson, M. E. Davis, K. A. Henderson, V. S. Zagorodnov, J. F. Bolzan, Byrd Polar Research Center, Department of Geological Sciences, The Ohio State University, Columbus, OH 43210, USA. E. Mosley-Thompson, Byrd Polar Research Center, D.
Science (New York, N.Y.)
|December 4, 1998
概括
玻利维亚冰芯揭示了在晚期冰川阶段的热带气候变化. 较低的尘埃和氧同位素表明较湿的条件和温度变化,表明气候事件的大气驱动因素.
科学领域:
- 古气候学 古气候学
- 冰川学的冰川学
- 热带气候动态 热带气候动态
背景情况:
- 冰芯是过去气候状况的关键档案.
- 热带地区为全球气候模式提供了独特的见解.
- 之前的研究已经确定了全球气候趋势,但热带记录不太常见.
研究的目的:
- 利用冰芯数据重建了晚期冰川时期的热带气候变化.
- 调查热带地区突然气候事件的驱动因素.
- 为了比较热带气候信号与极地地区的气候信号.
主要方法:
- 来自玻利维亚萨贾马山的冰芯的回收和分析.
- 碳-14年代测定用于时间控制.
- 氧同位素分析以推断温度和降水变化.
- 测量尘埃度以评估大气条件和干旱度.
主要成果:
- 萨贾马冰芯提供了碳-14日期的热带记录,延伸到晚期冰川阶段.
- 氧同位素的比率显示,从早期的全新世纪到最后的冰川最大值的显著下降.
- 一个年轻德里亚斯类型的事件呈现出突然的开始和结束,指向大气驱动因素.
- 区域冰积累在晚期冰川阶段,降冰和过去3000年期间增加,与更高的古湖水位相关.
- 与全新纪冰相比,萨贾马冰川的灰尘含量明显较低,这表明条件更加潮湿.
结论:
- 萨贾马冰芯记录提供了宝贵的热带气候数据,补充了极地记录.
- 大气过程可能导致了突然的气候变化,包括年轻的德里亚斯式事件.
- 地区湿度增加和雪地覆盖在热带安第斯地区的潮湿时期的特点.
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