New Perspectives on Observed and Simulated Antarctic Sea Ice Extent Trends Using Optimal Fingerprinting Techniques
New Perspectives on Observed and Simulated Antarctic Sea Ice Extent Trends Using Optimal Fingerprinting Techniques
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DOI：
10.1175/jcli-d-14-00367.1
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发表时间：
2015-02-01
影响因子：
4.9
通讯作者：
Raphael, Marilyn N.
中科院分区：
文献类型：
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作者：
Hobbs, William Richard;Bindoff, Nathaniel L.;Raphael, Marilyn N.
利用最佳指纹技术，进行检测分析，以确定自1979年以来观察到的南大洋海冰范围趋势是否超出自然变异的预期范围。与以前的研究一致，发现对于海冰覆盖最大的季节（即，在冬季和早春），观察到的趋势并没有超出自然变化的范围，在南极西部的一些地区，它们可能部分是由于热带变化造成的。然而，当分析中包括有关趋势的空间格局的信息时，夏季和秋季的趋势落在内部变化的范围之外。在罗斯海和阿蒙森-别林斯高晋海地区，可探测到的信号主要是强烈的相反趋势。与观测到的模式相反，20个CMIP 5耦合气候模式的集合表明，预计罗斯海冰覆盖将减少，以响应外部强迫。在罗斯，别林斯高晋，和阿蒙森海秋季的模拟减少显着不同，从非强迫的内部变异在95%的置信水平。与早期的工作不同，作者正式表明，模拟的海冰对外部强迫的响应与观测到的趋势和模拟的内部变率不同，并得出结论，CMIP 5模型一般不能充分代表南极气候系统的强迫响应。
Using optimal fingerprinting techniques, a detection analysis is performed to determine whether observed trends in Southern Ocean sea ice extent since 1979 are outside the expected range of natural variability. Consistent with previous studies, it is found that for the seasons of maximum sea ice cover (i.e., winter and early spring), the observed trends are not outside the range of natural variability and in some West Antarctic sectors they may be partially due to tropical variability. However, when information about the spatial pattern of trends is included in the analysis, the summer and autumn trends fall outside the range of internal variability. The detectable signal is dominated by strong and opposing trends in the Ross Sea and the Amundsen-Bellingshausen Sea regions. In contrast to the observed pattern, an ensemble of 20 CMIP5 coupled climate models shows that a decrease in Ross Sea ice cover would be expected in response to external forcings. The simulated decreases in the Ross, Bellingshausen, and Amundsen Seas for the autumn season are significantly different from unforced internal variability at the 95% confidence level. Unlike earlier work, the authors formally show that the simulated sea ice response to external forcing is different from both the observed trends and simulated internal variability and conclude that in general the CMIP5 models do not adequately represent the forced response of the Antarctic climate system.