Non-trivial role of internal climate feedback on interglacial temperature evolution
Non-trivial role of internal climate feedback on interglacial temperature evolution
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内部气候反馈对间冰期温度演化的重要作用
DOI：
10.1038/s41586-021-03930-4
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发表时间：
2021
期刊：
影响因子：
64.8
通讯作者：
Chen, Fahu
中科院分区：
文献类型：
--
作者：
Zhang, Xu;Chen, Fahu
量化替代重建中的季节偏差(例如，海洋表面温度(SST))一直是一个长期存在的挑战，阻碍了我们对过去气候演变(例如，全新世温度难题)的理解1，2。3提出了一种季节平均年转换(SAT)方法，该方法似乎能有效地消除由季节太阳辐射变化引起的SST信号。为了提取全新世(距今12-000年)的年平均海温(MASST)变化，Bova等人。3个精选的SST记录，另外还涵盖最后一个间冰期(LIG；128-115 KYR BP)，假定SST完全归因于当地太阳辐射的变化，因此能够可靠地量化SST记录的季节性偏差。然而，这一假设是根本不正确的，因为它忽略了地球系统内部反馈(例如海冰)对LIG温度变化的作用，表明他们的发现通过过度修正SST替代指标中由日照引起的季节性偏差而有效地存在偏差。我们同意，在LIG期间，全球冰量和温室气体浓度相对稳定(图1a，b)，与季节性日照变化相比，它们对经季节调整的SST(SSTsn)变化的直接贡献可能微不足道。然而，这并不意味着当代系统的内部反馈也有微不足道的作用。在各种内部反馈(如海冰、云、植被等)中，海冰是LIG的一个有代表性的例子，因为它经历了重建4、5和气候模式5-7所表明的重大当代进展。海冰-反照率反馈是公认的关于温度变化的有效正反馈。最近，英格兰等人。8在其他现代气候背景下，采用典型的集中路径8.5海冰情景--包括南大洋冬季海冰损失约35%和北极夏季海冰损失约70%(常年海冰残存)--进行了敏感性试验。他们发现，极地海冰的消失可以直接导致热带MASST增加0.6摄氏度以上(图2)。特别是，Bova等人使用的所有核心位置。在LIG(128-125KYR BP)的高峰暖期，两极地区的海冰都经历了显著的海冰损失4，5(例如，南极冬季海冰可能已经消退了65%(参考文献)。北极可能出现了夏季无海冰的情况，这一情况比参考文献中规定的情况要多。8.此后，海冰体积显著增加(注意，它们的驱动机制可能不同--前者主要由倾角引起的年平均日照强度驱动
Quantifying seasonal bias in proxy reconstructions (for example, sea surface temperature (SST)) has been a long-standing challenge, hampering our understanding of past climate evolution (for example, the Holocene temperature conundrum) 1, 2. Recently, Bova et al. 3 proposed a seasonal to mean annual transformation (SAT) method that seems to effectively remove SST signal caused by seasonal insolation change. To extract mean annual SST (MASST) change for the Holocene epoch (12–0 thousand years before present (kyr bp)), Bova et al. 3 selected SST records that additionally cover the last interglacial (LIG; 128–115 kyr bp) period, for which SST is assumed to be solely attributed to variations in local solar insolation, hence allowing for reliable quantification of seasonal bias in SST records. However, this assumption is fundamentally incorrect because it overlooks the roles of internal Earth system feedback (for example, sea ice) on LIG temperature change, indicating that their findings are effectively biased by overcorrecting insolation-induced seasonal bias in SST proxies. We agree that global ice volume and greenhouse gas concentrations were relatively stable during the LIG (Fig. 1a, b) and their direct contributions to seasonally unadjusted SST (SSTsn) changes might be trivial, in comparison to the seasonal insolation change. However, this does not mean that contemporary internal feedbacks of the system also have a trivial role. Among various internal feedbacks (for example, sea ice, cloud, vegetation and so on), sea ice is one representative example for the LIG because it experienced significant contemporary advances as suggested by reconstructions 4, 5 and climate models 5–7. Sea ice–albedo feedback is a well-acknowledged effectively positive feedback on temperature changes. Recently, England et al. 8 conducted a sensitivity experiment applying a Representative Concentration Pathway 8.5 sea-ice scenario—including an approximately 35% winter sea-ice loss in the Southern Ocean and an approximately 70% summer sea-ice loss in the Arctic (perennial sea-ice remnants persist)—under an otherwise present-day climate background. They found that the polar sea-ice loss can directly cause an increase of tropical MASST by more than 0.6 C (Fig. 2). In particular, all of the core locations used in Bova et al. 3 are characterized by mean annual warming with magnitudes in a range between 0.4 and 1 C.During the peak warm period of the LIG (128–125 kyr bp), both polar regions experienced significant sea-ice losses 4, 5 (for example, Antarctic winter sea ice may have retreated by up to 65%(ref. 6) and a summer sea-ice-free condition probably happened in the Arctic 7) that were more than those imposed in ref. 8. Following that, sea-ice volume increased markedly (note that their driving mechanisms might be different—the former is mainly driven by obliquity-induced mean annual insolation
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影响因子：
30.7
作者：
Guarino, Maria-Vittoria;Sime, Louise C.;Sellar, Alistair
通讯作者：
Sellar, Alistair
影响因子：
18.3
作者：
England, Mark R.;Polvani, Lorenzo M.;Deser, Clara
通讯作者：
Deser, Clara
浮游有孔虫的沉积；
DOI：
--
发表时间：
1984
期刊：
影响因子：
--
作者：
R. Thunell;L. Reynolds
通讯作者：
L. Reynolds
使用社区气候系统模型版本 3 对当前和末次间冰期气候进行瞬态模拟：轨道加速的影响
影响因子：
5.1
作者：
V. Varma;M. Prange;M. Schulz
通讯作者：
M. Schulz
影响因子：
3.5
作者：
Barker, Stephen;Knorr, Gregor;Thornalley, David
通讯作者：
Thornalley, David