doi:  10.3878/j.issn.1006-9895.1806.18116
观测分析非洲南部地区土壤湿度异常对南半球大气环流的显著影响

The influence of Southern Africa Soil Moisture Anomalies on the Southern Hemisphere Atmospheric Circulation
摘要点击 1120  全文点击 191  投稿时间:2018-01-23  修订日期:2018-04-17
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基金:  国家自然科学基金,国家重点基础研究规划项目
中文关键词:  土壤湿度,非洲南部地区,最大协方差分析,南极涛动
英文关键词:  soil moisture  Southern Africa  maximum covariance analysis  Antarctic Oscillation
     
作者中文名作者英文名单位
荀爱萍XUN Aiping海峡气象开放实验室;厦门市气象台
吴其冈WU Qigang复旦大学大气与海洋科学系,大气科学研究院
引用:荀爱萍,吴其冈.2018.观测分析非洲南部地区土壤湿度异常对南半球大气环流的显著影响[J].大气科学
Citation:XUN Aiping,WU Qigang.2018.The influence of Southern Africa Soil Moisture Anomalies on the Southern Hemisphere Atmospheric Circulation[J].Chinese Journal of Atmospheric Sciences (in Chinese)
中文摘要:
      本文基于44年ERA40再分析月平均土壤湿度资料和大气环流变量场资料,去除ENSO遥相关以及趋势影响后,利用滞后最大协方差方法分析非洲南部地区土壤湿度分布与南半球大气环流异常之间的线性耦合。第一最大协方差模态的结果表明:在南半球冬季(JJA)和夏季(JFM),大气中类似南极涛动(AAO)正位相的环流型与超前月份(最长时间达到5个月)的非洲南部地区土壤湿度的异常分布显著相关。基于土壤湿度变率中心的线性回归分析方法证实非洲南部地区其北部土壤湿度正异常、中南部土壤湿度负异常的空间分布对后期夏季和冬季的大气有显著的反馈作用。诊断结果显示由于夏秋季节和春季初夏非洲南部地区土壤湿度异常均有显著的持续性,同时对后期AAO产生持续增强作用,所以滞后最大协方差方法可以检测出它们对后期AAO的显著影响。以上非洲南部地区土壤湿度异常超前于南极涛动的信号,将有助于加强对土壤湿度反馈机制及其对南半球大尺度环流变率影响的认识。
Abstract:
      This study uses maximum covariance analysis (MCA) to investigate the linear covariance between anomalous soil moisture at Southern Africa and Southern Hemisphere (SH) atmospheric circulation based on the ERA40 reanalysis dataset. In austral winter (JJA) and summer (JFM), the atmospheric signal resembling the positive phase of the Antarctic Oscillation (AAO) was significantly correlated with persistently changing soil moisture anomalies in Southern Africa up to the five months in the leading MCA modes. Regression analysis based on the soil moisture anomaly centers form the MCA covariance patterns confirm that the early-seasonal positive soil moisture anomaly in the northern part of Southern Africa and the negative soil moisture anomaly in the central and southern part of Southern Africa have significant effects on lagged winter and summer atmospheric circulation. Significant Squared covariance of JJA (JFM) AAO seems to have some relation to a persistent soil moisture of the preceding summer and autumn (spring and early summer) and its consecutive and cumulative impacts on later atmosphere.The leading time of Southern Africa soil moisture anomaly provides an implication for skillful predictability of austral winter and summer SH large-scale atmospheric variability.
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