An Assessment of the Temporal Variability in the Annual Cycle of Daily Antarctic Sea Ice in the NCAR Community Earth System Model, Version 2: A Comparison of the Historical Runs With Observations
An Assessment of the Temporal Variability in the Annual Cycle of Daily Antarctic Sea Ice in the NCAR Community Earth System Model, Version 2: A Comparison of the Historical Runs With Observations
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NCAR 社区地球系统模型中每日南极海冰年度循环的时间变化评估，版本 2：历史运行与观测的比较
DOI：
10.1029/2020jc016459
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Landrum, Laura L.
中科院分区：
文献类型：
--
作者：
Raphael, Marilyn N.;Handcock, Mark S.;Holland, Marika M.;Landrum, Laura L.
鉴于观测数据的局限性，了解南极海冰的变化是一项持续的挑战。耦合气候模式模拟为研究南极海冰的这种变异性提供了机会。在这里，新发布的美国国家大气研究中心（NCAR）社区地球系统模型第2版（CESM2）模拟的历史时期（1979-2014）的日海冰范围与同期卫星观测的日海冰范围进行了比较。这些比较是使用一套新开发的统计指标进行的，该指标估计了海冰范围在从长期年代际到短期日内尺度的时间尺度上的变化。评估的是年周期、趋势、日变化和波动性，这是一种新的统计数据，可以估计每日尺度上的可变性。结果表明，海冰日变化趋势以年代际变化为主，叠加有微弱的正线性趋势。CESM2模拟了可比的年代际变化，但叠加了强烈的负线性趋势。CESM2的年周期在振幅上与观测到的相似，关键的区别在于冰前进和后退的时间。在CESM2中，海冰较晚开始前进，较晚达到最大值，较晚开始退缩。日复一日的变化证实了这一点。在所有的海冰区都很明显，这种行为表明了半年一次的环极槽振荡的影响。与较小尺度动力学（如风暴）相关的波动率在CESM2中比观测到的要小。
Understanding the variability of Antarctic sea ice is an ongoing challenge given the limitations of observed data. Coupled climate model simulations present the opportunity to examine this variability in Antarctic sea ice. Here, the daily sea ice extent simulated by the newly released National Center for Atmospheric Research (NCAR) Community Eart h System Model Version 2 (CESM2) for the historical period (1979–2014) is compared to the satellite‐observed daily sea ice extent for the same period. The comparisons are made using a newly developed suite of statistical metrics that estimates the variability of the sea ice extent on timescales ranging from the long‐term decadal to the short term, intraday scales. Assessed are the annual cycle, trend, day‐to‐day change, and the volatility, a new statistic that estimates the variability at the daily scale. Results show that the trend in observed daily sea ice is dominated by subdecadal variability with a weak positive linear trend superimposed. The CESM2 simulates comparable subdecadal variability but with a strong negative linear trend superimposed. The CESM2's annual cycle is similar in amplitude to the observed, key differences being the timing of ice advance and retreat. The sea ice begins its advance later, reaches its maximum later and begins retreat later in the CESM2. This is confirmed by the day‐to‐day change. Apparent in all of the sea ice regions, this behavior suggests the influence of the semiannual oscillation of the circumpolar trough. The volatility, which is associated with smaller scale dynamics such as storms, is smaller in the CESM2 than observed.
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DOI：
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发表时间：
--
期刊：
Edinburgh medical journal
影响因子：
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作者：
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DOI：
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发表时间：
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影响因子：
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DOI：
--
发表时间：
1979
期刊：
影响因子：
--
作者：
A. Carleton
通讯作者：
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影响因子：
5.2
作者：
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通讯作者：
T. Bracegirdle;D. Stephenson;J. Turner;T. Phillips