1970年左右北半球海面温度的急剧下降
David W J Thompson1, John M Wallace, John J Kennedy
1Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, USA. davet@atmos.colostate.edu
Nature
|September 25, 2010
概括
20世纪的全球气温显示出一个变暖-冷却-变暖的模式. 从1968年到1972年,北半球海面温度的快速下降解释了半球差异,挑战了现有的气候变化模型.
科学领域:
- 气候科学 气候科学
- 海洋学 海洋学 海洋学
- 大气科学 大气科学
背景情况:
- 20世纪全球气温呈现出一种非单调的升温-降温-升温趋势.
- 这种模式通常归因于温室气体强迫,硫酸盐气溶和海洋多十年的变化.
- 硫酸盐气溶被认为显著影响二战后半球温度趋势差异.
研究的目的:
- 为了调查20世纪中叶温度趋势中半球差异的原因.
- 为了确定全球温度观察到的冷却阶段背后的驱动因素.
主要方法:
- 对历史海面温度 (SST) 数据集的分析.
- 检查北半球和南半球的温度趋势.
- 温度变化的时间与已知的气候强迫因素的比较.
主要成果:
- 北半球海面温度的显著下降 (约. 0.3°C) 在1968年至1972年之间发生.
- 这种快速冷却事件的时间范围比典型的气溶或海洋变异性要短.
- SST下降在数据集中是一致的,而不是由于测量偏差,北大西洋北部的幅度最大.
结论:
- 20世纪中叶半球温度差异主要是由北半球SST迅速下降所驱动的.
- 这一事件的快速发作表明了一种机制超出了已有的气溶或多十年的变化解释.
- 需要进一步的研究来了解这种突然的海洋冷却事件的原因.
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