On the basis of the EOF analysis of global geopotential height anomaly(GHA)field at 10 hPa level,the arctic oscillation(AO)and the means antarctic oscillation(AAO)can bedetected more obviously at the upper level of at...On the basis of the EOF analysis of global geopotential height anomaly(GHA)field at 10 hPa level,the arctic oscillation(AO)and the means antarctic oscillation(AAO)can bedetected more obviously at the upper level of atmosphere than the AO or the AAO in surface layer.Unlike the hemisphere pattern of the AO and the AAO in the surface lager given by previous authors,the AO or the AAO in the stratosphere has its global features.The zonal oscillations—the SouthernOscillation(SO)and the north oscillation(NO)in atmospheric surface layer become less clear inthe upper air.The first mode(AO mode,abbreviated to AOM hereafter)and the second mode(AAO mode,abbreviated to AAOM hereafter)respectively have 41.47%and 27.04%of the total variancecontribution.The cumulative variance contribution of the first two modes reaches 68.51%.These twomodes are the main components for the interdecadal or decadal oscillation in the stratosphere.Inaddition,there still exist two kinds of oscillation patterns with less probability,namely,thesymmetric pattern at mid-high latitudes in the Southern Hemisphere and the asymmetric pattern.Spectral analysis shows that the AOM and the AAOM all have a spectral peak for 22 a period,beingconsistent with the periodic variations of the solar magnetic field,and a peak for 11 a period,being consistent with the period of the numbers of sunspots.Step filter analysis shows that theinfluencing factor for the upper atmospheric oscillation is the solar activity.The fluctuation ofthe solar magnetic field is the more influencing factor than the variation of the sunspot number.展开更多
基金supprted by the National Natural Science Foundations of China under contract Nos 40475033 and 40305009.
文摘On the basis of the EOF analysis of global geopotential height anomaly(GHA)field at 10 hPa level,the arctic oscillation(AO)and the means antarctic oscillation(AAO)can bedetected more obviously at the upper level of atmosphere than the AO or the AAO in surface layer.Unlike the hemisphere pattern of the AO and the AAO in the surface lager given by previous authors,the AO or the AAO in the stratosphere has its global features.The zonal oscillations—the SouthernOscillation(SO)and the north oscillation(NO)in atmospheric surface layer become less clear inthe upper air.The first mode(AO mode,abbreviated to AOM hereafter)and the second mode(AAO mode,abbreviated to AAOM hereafter)respectively have 41.47%and 27.04%of the total variancecontribution.The cumulative variance contribution of the first two modes reaches 68.51%.These twomodes are the main components for the interdecadal or decadal oscillation in the stratosphere.Inaddition,there still exist two kinds of oscillation patterns with less probability,namely,thesymmetric pattern at mid-high latitudes in the Southern Hemisphere and the asymmetric pattern.Spectral analysis shows that the AOM and the AAOM all have a spectral peak for 22 a period,beingconsistent with the periodic variations of the solar magnetic field,and a peak for 11 a period,being consistent with the period of the numbers of sunspots.Step filter analysis shows that theinfluencing factor for the upper atmospheric oscillation is the solar activity.The fluctuation ofthe solar magnetic field is the more influencing factor than the variation of the sunspot number.
