High-resolution marine data and transient simulations support orbital forcing of ENSO amplitude since the mid-Holocene
High-resolution marine data and transient simulations support orbital forcing of ENSO amplitude since the mid-Holocene
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DOI：
10.1016/j.quascirev.2021.107125
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发表时间：
2021-08-20
影响因子：
4
通讯作者：
Harrison, Sandy P.
中科院分区：
文献类型：
--
作者：
Carre, Matthieu;Braconnot, Pascale;Harrison, Sandy P.
缺乏对厄尔尼诺南方涛动（ENSO）的空间和长期时间变化的约束及其对外部强迫的敏感性限制了我们评估气候模式和ENSO未来预测的能力。目前的知识全新世ENSO变率来自古气候重建没有分开的作用，从内部气候变率的日照强迫。使用更新的合成珊瑚和双壳类每月解决的记录，我们建立复合记录的季节性和年际变化在热带太平洋的四个地区：东太平洋（EP），中太平洋（CP），西太平洋（WP）和西南太平洋（SWP）。的不确定性分析，由于采样的混乱的几十年到百年的变化短记录允许使用四个不同的地球系统模型进行的瞬态模拟（中全新世到现在）的客观比较。海表温度和伪三角洲O-18用于模型数据比较，以评估水文气候变化对记录的潜在影响。我们证实了全新世ENSO极小期（HEM）3- 6 ka与ENSO低频非强迫调制相比的重要性，EP中ENSO方差减少了50%，CP中减少了80%。该方法表明，ENSO自6 ka以来的增加趋势可以归因于日射，而模型低估了ENSO对轨道强迫的敏感性，与数据相比为4.7倍，即使考虑到大的多年变化。岁差引起的季节性温度范围的变化是正相关的ENSO变化在EP和在较小程度上在其他地区，在模型和观测。我们的区域方法产生的见解，过去的空间表达ENSO整个热带太平洋。在SWP中，今天在南太平洋辐合带（SPCZ）的影响下，年际变率在HEM期间增加了近200%，表明SPCZ变率在千年时间尺度上独立于ENSO。(C)2021年，任作家。爱思唯尔有限公司出版
Lack of constraint on spatial and long-term temporal variability of the El Nino southern Oscillation (ENSO) and its sensitivity to external forcing limit our ability to evaluate climate models and ENSO future projections. Current knowledge of Holocene ENSO variability derived from paleoclimate reconstructions does not separate the role of insolation forcing from internal climate variability. Using an updated synthesis of coral and bivalve monthly resolved records, we build composite records of seasonality and interannual variability in four regions of the tropical Pacific: Eastern Pacific (EP), Central Pacific (CP), Western Pacific (WP) and South West Pacific (SWP). An analysis of the uncertainties due to the sampling of chaotic multidecadal to centennial variability by short records allows for an objective comparison with transient simulations (mid-Holocene to present) performed using four different Earth System models. Sea surface temperature and pseudo-delta O-18 are used in model-data comparisons to assess the potential influence of hydroclimate change on records. We confirm the significance of the Holocene ENSO minimum (HEM) 3-6ka compared to low frequency unforced modulation of ENSO, with a reduction of ENSO variance of similar to 50 % in EP and similar to 80 % in CP. The approach suggests that the increasing trend of ENSO since 6ka can be attributed to insolation, while models underestimate ENSO sensitivity to orbital forcing by a factor of 4.7 compared to data, even when accounting for the large multidecadal variability. Precession-induced change in seasonal temperature range is positively linked to ENSO variance in EP and to a lesser extent in other regions, in both models and observations. Our regional approach yields insights into the past spatial expression of ENSO across the tropical Pacific. In the SWP, today under the influence of the South Pacific Convergence Zone (SPCZ), interannual variability was increased by similar to 200 % during the HEM, indicating that SPCZ variability is independent from ENSO on millennial time scales. (C) 2021 The Authors. Published by Elsevier Ltd.