古海洋学.古海洋学. 南极在北半球冰川化中的作用
Stella C Woodard1, Yair Rosenthal2, Kenneth G Miller3
1Department of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901, USA. woodard@marine.rutgers.edu.
概括
北半球冰期开始于273万年前. 由于南极冰川的增长,更冷的太平洋水域和改变的海洋循环,促进了这种主要的气候过渡.
科学领域:
- 古气候学 古气候学
- 海洋学 海洋学 海洋学
- 气候科学 气候科学
背景情况:
- 地球的气候从温暖的普略纪气候转变为北半球广泛的冰川 (NHG) 大约2.73亿年前 (Ma).
- 在NHG前,北太平洋深水明显比北大西洋深水更冷,更新鲜.
研究的目的:
- 为了研究在北半球冰期开始之前和期间的深海循环变化.
- 了解半球间热量和盐运输在这种重大气候转型中的作用.
主要方法:
- 深海温度和盐度的古海洋学重建.
- 对海平面变化的分析,以推断南极冰川的范围.
- 深海循环动态的建模.
主要成果:
- 在NHG加剧之前,北太平洋深水比北大西洋深水冷和新鲜约4°C.
- 大西洋-太平洋温度梯度在2.73 Ma左右降至<1°C,表明热量转移到太平洋的增强.
- 海平面在3.15至2.75万年前的21±10米下降表明南极冰川的增加.
结论:
- 增加的南极冰川和强烈的极地光环线从根本上改变了深海循环.
- 增强的半球间热量和盐运输对北半球冰川的出现做出了重大贡献.
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