| 近20 a驱动北极夏季迅速增暖和融冰的自然因素及过程 |
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| 引用本文： | 丁庆华.近20 a驱动北极夏季迅速增暖和融冰的自然因素及过程[J].大气科学学报,2021,44(1):39-49. |
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| 作者姓名： | 丁庆华 |
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| 作者单位： | 加州大学 圣巴巴拉分校地理系, 美国加州 圣巴巴拉市 93106 |
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| 摘 要： | 北极是全球气候系统平衡的重要一环,近20 a全球变暖现象中,北极迅速增温及融冰是最为引人关注的问题之一。人类影响无疑是过去几十年北极变暖背后的最主要的原因及驱动力,但气候系统的内在自然变率对北极的影响也不容忽视。本文指出,北极变暖的自然影响因子有一部分来源于热带太平洋东部海温的变化,热带太平洋通过由东部海温异常所驱动的大尺度遥相关环流型来影响北极的气候系统,该影响过程在过去20 a的演化是由热带海温的冷异常趋势所触发的。海温的冷异常通过遥相关波列在北极建立起一个异常的高压系统,并通过对大气温度的绝热加热来增加大气向下的长波辐射以加速海冰的融化,该作用在北半球夏天尤为明显,且于2007—2012年达到最大强度。此热带海温异常可能与IPO(the Interdecadal Pacific Oscillation,太平洋年代际振荡)有关,且其对高纬气候的影响可能不同于典型ENSO对高纬气候的作用。通过对CMIP5气候模式的检验可发现,大部分模式对这个热带与北极联系的模拟都存在着显著的偏差和缺陷,具体原因仍需更多研究。本文给出了有关模式局限性的一些猜想,讨论了2020年夏季海冰快速融化的原因,并通过比较2020年夏季的环流异常与之前41 a(1979—2019年)与海冰融化紧密联系的大尺度环流型,进一步探究了2020年夏季热带东太平洋海温的冷异常对北极当季增温及融冰是否具有显著作用。
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| 关 键 词： | 北极增温及海冰融化 气候变化 热带-中高纬相互作用 遥相关环流型 模式评估及检验 |
| 收稿时间： | 2020/11/13 0:00:00 |
| 修稿时间： | 2020/11/28 0:00:00 |
Internal atmospheric processes contributing to Arctic summer rapid warming and ice melting in recent 20 years |
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| DING Qinghua.Internal atmospheric processes contributing to Arctic summer rapid warming and ice melting in recent 20 years[J].大气科学学报,2021,44(1):39-49. |
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| Authors: | DING Qinghua |
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| Institution: | Department of Geography,University at Santa Barbara,University of California,Santa Barbara,California 93106,USA |
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| Abstract: | The Arctic climate,an important component of the global climate system,has moved into a new state over the past 20 years.Scientific questions and possible consequences related to these changes are now front in the midst of many important issues that the world needs to deal with in the future.These changes,including prominent atmospheric and oceanic warming and sea ice melting have been largely attributed to a combined effect of anthropogenic forcing and internal variability of the climate system.This review highlights some findings from a number of studies conducted by my research group in the past few years.The studies collectively suggest that the high latitude atmospheric circulation that is sensitive to tropical SST forcing related to the interdecadal Pacific oscillation (IPO) plays a vital role in driving the interannual and interdecadal variability of Arctic sea ice by affecting the atmospheric temperature,moisture,clouds and radiative fluxes over sea ice.In particular,the teleconnection excited by a SST cooling over the tropical Pacific is suggested to cause an enhanced melting from 2007 to 2012.In addition,it suggests that a similar internal process may also play a role to cause strong sea ice melting in summer 2020.Furthermore,the model evaluation focusing on CMIP5 models finds that most climate models have a limitation to replicate this IPO-related teleconnection,raising awareness on an urgent need to investigate the cause of this bias in models.Thus,this review is meant to offer priorities for future Arctic research so that more efforts are targeted on critical scientific questions raised in this study. |
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| Keywords: | Arctic warming and sea ice melting climate change tropical-extratropical interaction teleconnection circulation pattern model evaluation and validation |
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