瑞士苏黎世大气与气候科学研究所Knutti, Reto课题组近日取得一项新成果。他们报道了20世纪早期海洋表面温度观测中的冷偏倚。相关论文于2024年11月20日发表于国际顶尖学术期刊《自然》。

观测到的温度记录结合了海面温度和陆地近地表空气温度，对于理解气候变率和变化至关重要。然而，由于测量技术和实践的变化，部分文献5、6、7、8和空间覆盖不完整，早期的全球平均地表温度记录是不确定的。

本文表明，根据海洋或陆地数据对全球平均表面温度的独立统计重建，现有的20世纪初（1900-1930年）海洋温度估计过低。海洋重建平均约为0.26比陆地上的温度低°C，尽管在其他时期的一致性非常高。海洋冷异常是非强迫的，气候模式的内部变率不能解释观测到的陆洋差异。

基于归因、时间尺度分析、沿海网格单元和古气候数据的几条证据线，支持在20世纪初观测到的全球海洋表面温度记录中存在明显的冷偏倚的论点。虽然对19世纪中叶以来全球变暖的估计不受影响，但纠正海洋冷偏倚将导致20世纪早期的变暖趋势更为温和，从仪器记录推断出的年代际变率估计较低，模拟变暖和观测变暖之间的一致性比现有数据集所显示的更好。

附：英文原文

Title: Early-twentieth-century cold bias in ocean surface temperature observations

Author: Sippel, Sebastian, Kent, Elizabeth C., Meinshausen, Nicolai, Chan, Duo, Kadow, Christopher, Neukom, Raphael, Fischer, Erich M., Humphrey, Vincent, Rohde, Robert, de Vries, Iris, Knutti, Reto

Issue&Volume: 2024-11-20

Abstract: The observed temperature record, which combines sea surface temperatures with near-surface air temperatures over land, is crucial for understanding climate variability and change1,2,3,4. However, early records of global mean surface temperature are uncertain owing to changes in measurement technology and practice, partial documentation5,6,7,8, and incomplete spatial coverage9. Here we show that existing estimates of ocean temperatures in the early twentieth century (1900–1930) are too cold, based on independent statistical reconstructions of the global mean surface temperature from either ocean or land data. The ocean-based reconstruction is on average about 0.26°C colder than the land-based one, despite very high agreement in all other periods. The ocean cold anomaly is unforced, and internal variability in climate models cannot explain the observed land–ocean discrepancy. Several lines of evidence based on attribution, timescale analysis, coastal grid cells and palaeoclimate data support the argument of a substantial cold bias in the observed global sea-surface-temperature record in the early twentieth century. Although estimates of global warming since the mid-nineteenth century are not affected, correcting the ocean cold bias would result in a more modest early-twentieth-century warming trend10, a lower estimate of decadal-scale variability inferred from the instrumental record3, and better agreement between simulated and observed warming than existing datasets suggest2.

DOI: 10.1038/s41586-024-08230-1

Source: https://www.nature.com/articles/s41586-024-08230-1