The role of the North Atlantic Oscillation in European climate projections
The role of the North Atlantic Oscillation in European climate projections
复制标题
DOI：
10.1007/s00382-016-3502-z
复制
发表时间：
2017-11-01
期刊：
影响因子：
4.6
通讯作者：
Phillips, Adam S.
中科院分区：
文献类型：
--
作者：
Deser, Clara;Hurrell, James W.;Phillips, Adam S.
这项研究强调了由于北大西洋涛动（NAO）叠加在人为气候变化上的不可预测的波动，未来30-50年预计冬季气温和降水趋势的预期范围。研究结果是基于一个40名成员的初始条件集合的模拟，涵盖了1920年至2100年期间进行的共同体地球系统模型版本1（CESM 1）在1A度的空间分辨率。欧洲、俄罗斯和中东部分地区的预计温度和降水趋势的大小（在某些地区，甚至是符号）在整个集合中变化很大，这取决于每个成员中NAO的演变。因此，NAO的内部变化在未来几十年内对区域气候的未来变化产生了很大的不确定性。为了验证模型的结果，我们采用了一个简单的缩放方法，涉及的误差幅度的年际变化的统计趋势。通过这种方式，我们可以使用观测到的NAO记录的年际统计数据结合模式的辐射强迫响应（由40次模拟的集合平均值给出）来获得预测气候趋势的预期范围。这种基于观测的估计结果与直接从CESM集合获得的结果相似，证明了模型表示NAO的保真度和这种方法的实用性。最后，我们注意到，NAO和相关的地面气候影响的年际统计数据受到不确定性，由于采样波动，即使是基于一个世纪的数据。
This study highlights the expected range of projected winter air temperature and precipitation trends over the next 30-50 years due to unpredictable fluctuations of the North Atlantic Oscillation (NAO) superimposed upon forced anthropogenic climate change. The findings are based on a 40-member initial-condition ensemble of simulations covering the period 1920-2100 conducted with the Community Earth System Model version 1 (CESM1) at 1A degrees spatial resolution. The magnitude (and in some regions, even the sign) of the projected temperature and precipitation trends over Europe, Russia and parts of the Middle East vary considerably across the ensemble depending on the evolution of the NAO in each individual member. Thus, internal variability of the NAO imparts substantial uncertainty to future changes in regional climate over the coming decades. To validate the model results, we apply a simple scaling approach that relates the margin-of-error on a trend to the statistics of the interannual variability. In this way, we can obtain the expected range of projected climate trends using the interannual statistics of the observed NAO record in combination with the model's radiatively-forced response (given by the ensemble-mean of the 40 simulations). The results of this observationally-based estimate are similar to those obtained directly from the CESM ensemble, attesting to the fidelity of the model's representation of the NAO and the utility of this approach. Finally, we note that the interannual statistics of the NAO and associated surface climate impacts are subject to uncertainty due to sampling fluctuations, even when based on a century of data.