| 春季欧亚大陆积雪对春夏季南北半球大气质量交换的可能影响 |
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| 引用本文： | 卢楚翰,管兆勇,李震坤,金大超,秦育婧.春季欧亚大陆积雪对春夏季南北半球大气质量交换的可能影响[J].大气科学,2014,38(6):1185-1197. |
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| 作者姓名： | 卢楚翰 管兆勇 李震坤 金大超 秦育婧 |
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| 作者单位： | 1.南京信息工程大学气象灾害省部共建教育部重点实验室/气象灾害预报预警与评估协同创新中心, 南京210044 |
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| 基金项目： | 国家自然科学基金项目41005046、41175062,国家重点基础发展计划(973计划)项目2010CB428602,江苏省自然科学基金项目BK2012465,江苏高校优势学科建设工程项目 |
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| 摘 要： | 本文基于春季欧亚雪盖资料与大气再分析资料的奇异值分解(SVD)分析结果,结合数值试验,研究了春季欧亚大陆积雪变化与春、夏季南北半球大气质量交换的联系。研究表明,当春季欧亚积雪异常偏多时,同期欧亚大陆中高纬大范围地区的地面气温异常偏低,这种冷却效应可能持续至夏季,同时,冷空气的堆积造成了欧亚大陆地表气压(气柱大气质量)的增加,并且对应了夏季北半球大气总质量的异常上升,而南半球大气质量却明显下降。分析发现,春季欧亚积雪异常与夏季南北半球际大气质量涛动存在显著的滞后相关,而且前者还与同期及后期包括索马里急流和对流层上部80°E~120°E区域高空急流在内的多处越赤道气流变化联系密切。从数值模拟结果分析发现,以改变春季初始积雪状况作为驱动,欧亚大陆中高纬地区的低层大气环流出现了显著响应,即当积雪增加时,同期及其后夏季地面气温显著降低,并且冷异常区域对应着气柱质量的异常升高。
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| 关 键 词： | 欧亚大陆积雪 南北半球大气相互作用 大气质量 越赤道气流 |
| 收稿时间： | 2013/10/19 0:00:00 |
| 修稿时间： | 2014/5/16 0:00:00 |
Effects on Inter-hemispheric Air Mass Exchange between the Southern and Northern Hemisphere by Eurasian Spring Snow |
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| LU Chuhan,GUAN Zhaoyong,LI Zhenkun,JIN Dachao and QIN Yujing.Effects on Inter-hemispheric Air Mass Exchange between the Southern and Northern Hemisphere by Eurasian Spring Snow[J].Chinese Journal of Atmospheric Sciences,2014,38(6):1185-1197. |
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| Authors: | LU Chuhan GUAN Zhaoyong LI Zhenkun JIN Dachao and QIN Yujing |
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| Institution: | 1.Key Laboratory of Meteorological Disaster of Ministry of Education, Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing 2100442.Shanghai Climate Center, Shanghai 200030 |
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| Abstract: | The relationship between Eurasian spring snow and the simultaneous and subsequent summer bi-hemispheric air mass exchange are examined using both Singular Value Decomposition (SVD) analysis for springtime snow cover and atmospheric data reanalysis along with general circulation model (GFDL AM2) ensemble simulations. The results can be summarized as follows. Remarkable negative (positive) correlations are revealed between Eurasian spring snow frequency and surface air temperature (columnar air mass) in the Eurasian continent. Following positive anomalous springtime snow, there are statistically significant negative spring surface air temperature (SAT) anomalies over Eurasian mid-and high-latitudes. This cooling effect can be sustained into the subsequent summer, bringing about increasing surface pressure (columnar air mass). Interestingly, with the rising of anomalous hemispherical air mass, such continental-scale cold air piling increases in the Northern Hemisphere but decreases in the Southern Hemisphere. Furthermore, both Eurasian spring snow cover index and time series of the first SVD mode of snow frequency display significant positive correlation with inter-hemispheric air mass oscillations (IHO). The correlation coefficients are 0.391 and 0.393, respectively. This associated bi-hemispheric imbalanced air mass is statistically correlated to cross-equator fluxes in the Eastern Hemisphere in both spring and summer, including the Somali Jet and the upper level jet stream from 80°E to 120°E. Our ensemble GCM simulations show that the notable response of surface general circulation displays over Eurasian mid-high latitudes forced by different initial snow mass conditions in spring. When snow mass increases in Eurasia, continental negative SATs are observed in spring and summer, thereby giving rise to increases in large-scale air masses. |
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| Keywords: | Eurasian snow Bi-hemispheric air interaction Air mass Cross-equator flux |
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