The Pliocene Model Intercomparison Project Phase 2: large-scale climate features and climate sensitivity
The Pliocene Model Intercomparison Project Phase 2: large-scale climate features and climate sensitivity
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DOI：
10.5194/cp-16-2095-2020
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发表时间：
2020-11-04
影响因子：
4.3
通讯作者：
Lunt, Daniel J.
中科院分区：
文献类型：
--
作者：
Haywood, Alan M.;Tindall, Julia C.;Lunt, Daniel J.
上新世极有可能提高我们对大气中二氧化碳浓度接近百万分之400的长期气候和环境后果的理解。本文介绍了基于边界条件重建的不同复杂性和空间分辨率的新气候模式集合（上新世模式比对项目第二阶段；PlioMIP2）所模拟的上新世气候的大尺度特征。作为全球年平均值，模拟的地表气温相对于工业化前时代增加了1.7至5.2摄氏度，多模式平均值为3.2摄氏度。年平均总降水量增加7%（范围：2% - 13%）。平均而言，地表气温（SAT）在陆地上上升了4.3摄氏度，在海洋上上升了2.8摄氏度。北极向北纬60度和南纬60度方向的变暖明显超过全球平均变暖的2.3倍。在大西洋和太平洋，经向温度梯度减小，而热带纬向温度梯度基本保持不变。与CO2加倍相关的模式气候响应（平衡气候敏感性；ECS）与其模拟的上新世地表温度响应之间存在统计学上显著的关系。地球系统对二氧化碳增加一倍的平均总体响应（包括冰盖反馈）比ECS高67%；这比从PlioMIP1集合中获得的47%的增幅要大。通过对上新世海面温度的代理估算来评估模式对ECS的估算，得到的ECS范围为2.6-4.8摄氏度。这一结果与政府间气候变化专门委员会（IPCC）以前的评估报告中提出的ECS范围基本一致。
The Pliocene epoch has great potential to improve our understanding of the long-term climatic and environmental consequences of an atmospheric CO2 concentration near similar to 400 parts per million by volume. Here we present the large-scale features of Pliocene climate as simulated by a new ensemble of climate models of varying complexity and spatial resolution based on new reconstructions of boundary conditions (the Pliocene Model Intercomparison Project Phase 2; PlioMIP2). As a global annual average, modelled surface air temperatures increase by between 1.7 and 5.2 degrees C relative to the pre-industrial era with a multi-model mean value of 3.2 degrees C. Annual mean total precipitation rates increase by 7 % (range: 2 %-13 %). On average, surface air temperature (SAT) increases by 4.3 degrees C over land and 2.8 degrees C over the oceans. There is a clear pattern of polar amplification with warming polewards of 60 degrees N and 60 degrees S exceeding the global mean warming by a factor of 2.3. In the Atlantic and Pacific oceans, meridional temperature gradients are reduced, while tropical zonal gradients remain largely unchanged. There is a statistically significant relationship between a model's climate response associated with a doubling in CO2 (equilibrium climate sensitivity; ECS) and its simulated Pliocene surface temperature response. The mean ensemble Earth system response to a doubling of CO2 (including ice sheet feedbacks) is 67 % greater than ECS; this is larger than the increase of 47 % obtained from the PlioMIP1 ensemble. Proxy-derived estimates of Pliocene sea surface temperatures are used to assess model estimates of ECS and give an ECS range of 2.6-4.8 degrees C. This result is in general accord with the ECS range presented by previous Intergovernmental Panel on Climate Change (IPCC) Assessment Reports.