Simulated Atlantic Meridional Overturning Circulation in the 20th century with an ocean model forced by reanalysis-based atmospheric data sets
Simulated Atlantic Meridional Overturning Circulation in the 20th century with an ocean model forced by reanalysis-based atmospheric data sets
复制标题
利用基于再分析的大气数据集强制建立的海洋模型模拟 20 世纪大西洋经向翻转环流
DOI：
10.1016/j.ocemod.2015.12.011
复制
发表时间：
2016-04-01
期刊：
影响因子：
3.2
通讯作者：
Bentsen, Mats
中科院分区：
文献类型：
--
作者：
He, Yan-Chun;Drange, Helge;Bentsen, Mats
1871-2009年期间的全球海洋后报模拟已经使用挪威地球系统模型的海洋-海冰部分进行（NorESM-O），受20世纪世纪再分析第2版数据集的调整版本的影响（20 CRv 2数据集），以及协调海洋-冰参考实验第二阶段（CORE-II）常用的第二版大气强迫数据集1943-2007年期间（以下简称CORE.v2数据集）。在20 CR和CORE模拟中模拟的大西洋经向翻转环流（AMOC）在过去三十年的整合中具有可比的变异性以及平均强度。然而，在1948-1970年期间，模拟的AMOC经历了明显不同的演变，CORE强度急剧下降，而20 CR强度逐渐增加。敏感性实验表明，CORE和20 CR之间的风强迫的差异有重大影响的模拟AMOCs在此期间。进一步发现，两个数据集之间的空气温度的差异确实有助于AMOC的差异，但程度比风小得多。在1948年之后的二十年中，AMOC发散的另一个因素是由于海洋模式的周期性自旋过程，1948年基于CORE.v2的运行中大气强迫场不可避免的切换。后者是任何海洋后报模拟的根本问题。海洋初始状态主要影响AMOC的实际值，但在较小程度上也影响AMOC的时间演变（变率）。它可能需要大约20年的AMOC调整到一个新的大气状态，在自旋的过程中，虽然一个动态平衡的海洋初始状态往往会减少调整时间和偏差的幅度，这意味着一个海洋模式运行的大气强迫场延伸回的时间，如20 CRv 2，可以用来延长可靠的持续时间的核心类型的模拟。(C)2016爱思唯尔有限公司版权所有
Global ocean hindcast simulations for the period 1871-2009 have been run with the ocean-sea ice component of the Norwegian Earth System Model (NorESM-O), forced by an adjusted version of the Twentieth Century Reanalysis version 2 data set (20CRv2 data set), as well as by the commonly used second version of atmospheric forcing data set for the Coordinated Ocean-ice Reference Experiments phase-II (CORE-II) for the period 1943-2007 (hereafter CORE.v2 data set). The simulated Atlantic Meridional Overturning Circulation (AMOC) in the 20CR and the CORE simulations have comparable variability as well as mean strength during the last three decades of the integration. The simulated AMOC undergoes, however, distinctly different evolutions during the period 1948-1970, with a sharply declining strength in CORE but a gradual increase in 20CR. Sensitivity experiments suggest that differences in the wind forcing between CORE and 20CR have major impact on the simulated AMOCs during this period. It is furthermore found that differences in the air temperature between the two data sets do contribute to the differences in AMOC, but to a much lesser degree than the wind. An additional factor for the diverging AMOC in the two decades following 1948 is the inevitable switching of atmospheric forcing fields in 1948 in the CORE.v2-based runs due to the cyclic spin-up procedure of the ocean model. The latter is a fundamental issue for any ocean hindcast simulation. The ocean initial state mainly influence the actual value but to a lesser degree also the temporal evolution (variability) of AMOC. It may take about two decades for the AMOC to adjust to a new atmospheric state during the spin-up, although a dynamically balanced ocean initial state tends to reduce the adjustment time and the magnitude of the deviation, implying that an ocean model run with atmospheric forcing fields extending back in time, like 20CRv2, can be used to extend the reliable duration of CORE-type of simulations. (C) 2016 Elsevier Ltd. All rights reserved.