| 北大西洋高纬度海区湍流热通量对全球增暖的响应 |
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| 引用本文： | 程军,张瑾.北大西洋高纬度海区湍流热通量对全球增暖的响应[J].大气科学学报,2017,40(6):769-777. |
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| 作者姓名： | 程军 张瑾 |
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| 作者单位： | 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京, 210044;南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京, 210044 |
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| 基金项目： | 国家重大科学研究计划项目（2015CB953900；2016YFA0600500；2016YFA0600400）；国家自然基金资助项目（41776017；41630527）；江苏高校优势学科建设工程资助项目（PAPD） |
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| 摘 要： | 大西洋经向翻转环流(the Atlantic Meridional Overturning Circulation,AMOC)由低纬输送大量热量至高纬度北大西洋海区,并通过热通量由海洋输送给大气,主导了附近区域的气候形态,并对北半球尺度的气候变化产生显著影响。本文根据CMIP5多模式多增暖情景的预估模拟结果,通过与增暖前控制试验的对比发现,全球增暖可导致该海区湍流热通量的减小,且减小的幅度随增暖强度增大,模拟结果与观测一致。进一步研究发现,热通量的减小存在季节差异,冬季的减小幅度远大于夏季。结合淡水扰动试验的分析表明,全球增暖下AMOC强度的减弱导致大西洋经向热输送减少,进而导致高纬度北大西洋海洋向大气的热输送减小。
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| 关 键 词： | 湍流热通量 高纬度北大西洋海区 全球增暖 AMOC 经向热输送 |
| 收稿时间： | 2017/3/2 0:00:00 |
| 修稿时间： | 2017/9/14 0:00:00 |
The response of high-latitude North Atlantic surface turbulence heat flux to global warming |
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| CHENG Jun and ZHANG Jin.The response of high-latitude North Atlantic surface turbulence heat flux to global warming[J].大气科学学报,2017,40(6):769-777. |
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| Authors: | CHENG Jun and ZHANG Jin |
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| Institution: | Key Laboratory of Meteorological Disaster, Ministry of Education(KLMD)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing 210044, China;Key Laboratory of Meteorological Disaster, Ministry of Education(KLMD)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing 210044, China |
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| Abstract: | Immense heat of about 1 PW(1 PW=1 015 W) is transported by Atlantic Meridional Overturning Circulation(AMOC) from the low-latitude to high-latitude North Atlantic(HNA),and then released to the local atmosphere through surface turbulent heat flux,thus dominating the pattern of the local climate and climate changes over the Northern Hemisphere on multiple scales.Based on limited observations,previous works have observed a weakening trend in the turbulent heat flux of the HNA over the last part of 20th century,and have proposed that it is a result of global warming.To confirm these findings,in this study we investigate the response of HNA turbulent heat flux to global warming based on four warming scenario experiments of 13 CMIP5 models.The results show that the HNA turbulent heat flux significantly decreases under a warming climate,and that its weakening magnitude is larger under warmer scenarios.For the strongest warming scenario of Rcp 8.5,the multi-model averaged reduced magnitude of the HNA turbulent heat flux reaches about 40 W·m2,which is nearly 1/3 of the value before warming.Furthermore,the results of multi-model consistently show a stronger weakening of the HNA turbulent heat flux in winter.The multi-model averaged reduced magnitude of the HNA turbulent heat flux in winter is close to about 43 W·m-2,but the value in summer is only about 10 W·m-2,signifying that its magnitude in summer is less than 1/4 that in summer.The weakened HNA turbulent heat flux under warming is attributed to the weakened AMOC and its related reduced oceanic heat transport to the HNA.The results of a water-hosing experiment,using a fully coupled climate model of CCSM3,confirm the dominant contributions of weakened AMOC to reduced HNA turbulent heat flux under warming.The reduced turbulent heat flux of the HNA is a key factor to understanding the climate changes of the Northern Hemisphere under warming. |
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| Keywords: | surface turbulent heat flux high-latitude North Atlantic global warming AMOC meridional heat transport |
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