Correcting datasets leads to more homogeneous early-twentieth-century sea surface warming
Correcting datasets leads to more homogeneous early-twentieth-century sea surface warming
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DOI：
10.1038/s41586-019-1349-2
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发表时间：
2019-07-18
期刊：
影响因子：
64.8
通讯作者：
Huybers, Peter
中科院分区：
文献类型：
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作者：
Chan, Duo;Kent, Elizabeth C.;Huybers, Peter
现有的海面温度估计表明，在世纪早期，北大西洋和东北太平洋的升温幅度是全球平均值的两倍，而西北太平洋的降温幅度则与全球平均值相当（1-4）。这种不均匀的模式表明，强迫或海洋-大气热通量的区域变化的一阶贡献（5，6）。然而，这些较旧的SST估计值是从船上水桶中的水温测量值得出的，必须对重大偏差进行校正（7-9）。在这里，我们表明，桶测量组之间的偏移校正导致SST的变化，更好地与附近的土地温度和更均匀的变暖模式。通过系统地比较不同群体之间的附近SST观测值来确定偏移量（10）。对德国测量值的补偿进行校正会降低北大西洋的变暖速率，而对日本测量值的补偿进行校正会导致北太平洋变暖的增加和更均匀。日本在1930年代的测量偏移主要是由于在1960年代将记录数字化时将记录截断为整个摄氏度。这些发现强调了这样一个事实，即历史SST记录反映了数据收集中的物理和社会层面，并表明存在进一步的机会来提高历史SST记录的准确性（9，11）。
Existing estimates of sea surface temperatures (SSTs) indicate that, during the early twentieth century, the North Atlantic and northeast Pacific oceans warmed by twice the global average, whereas the northwest Pacific Ocean cooled by an amount equal to the global average(1-4). Such a heterogeneous pattern suggests first-order contributions from regional variations in forcing or in ocean-atmosphere heat fluxes(5,6). These older SST estimates are, however, derived from measurements of water temperatures in ship-board buckets, and must be corrected for substantial biases(7-9). Here we show that correcting for offsets among groups of bucket measurements leads to SST variations that correlate better with nearby land temperatures and are more homogeneous in their pattern of warming. Offsets are identified by systematically comparing nearby SST observations among different groups(10). Correcting for offsets in German measurements decreases warming rates in the North Atlantic, whereas correcting for Japanese measurement offsets leads to increased and more uniform warming in the North Pacific. Japanese measurement offsets in the 1930s primarily result from records having been truncated to whole degrees Celsius when the records were digitized in the 1960s. These findings underscore the fact that historical SST records reflect both physical and social dimensions in data collection, and suggest that further opportunities exist for improving the accuracy of historical SST records(9,11).