地球南北半球的非对称性
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摘要
依据新的计算分析和空间观测数据 ,进一步论述了地球南北半球的非对称性 .全球热散失量的计算得出 ,南半球高出北半球 3 3 %;南半球地幔热散失量是北半球的 2倍 .比较南北半球S波速度分布 ,得出南半球的上地幔为低速、高温 ,北半球的上地幔为高速、低温 .计算地幔各层的质心位置发现 ,地球的质心偏于北半球 .计算地球经、纬圈长度的年变化率表明 ,南半球在扩张 ,北半球在收缩 .用空间大地测量数据的检测结果证实 ,南半球处于扩张状态 ,北半球处于压缩状态 .对地球的非对称性作了初步的动力学解释 .
Asymmetry between the southern and northern hemispheres of the Earth is further stated on the basis of new calculations, analyses and observations of space geodesy. The calculation of global thermal loss shows that the thermal loss of the southern hemisphere is more than that of the northern hemisphere by 33%, while the thermal loss of the southern hemisphere mantle is the twice of that of the northern hemisphere. Comparing the S wave velocity distribution of the southern and northern hemispheres, we concluded that the upper mantle of the southern hemisphere is characterized by low velocity and high temperature, while the upper mantle of the northern hemisphere features high velocity and low temperatre. The calculated "mass center" of the mantle's layers implies that the mass center of the Earth is to the northern hemisphere. The annual variations of the longitudinal and latitudinal circle lengths demonstrate that the southern hemisphere appears to be expanding, while the northern hemisphere looks like contracting. These two contract states can be confirmed by the data of space geodetic measurement. A trial explanation for the asymmetry of the Earth is delivered.
Asymmetry between the southern and northern hemispheres of the Earth is further stated on the basis of new calculations, analyses and observations of space geodesy. The calculation of global thermal loss shows that the thermal loss of the southern hemisphere is more than that of the northern hemisphere by 33%, while the thermal loss of the southern hemisphere mantle is the twice of that of the northern hemisphere. Comparing the S wave velocity distribution of the southern and northern hemispheres, we concluded that the upper mantle of the southern hemisphere is characterized by low velocity and high temperature, while the upper mantle of the northern hemisphere features high velocity and low temperatre. The calculated "mass center" of the mantle's layers implies that the mass center of the Earth is to the northern hemisphere. The annual variations of the longitudinal and latitudinal circle lengths demonstrate that the southern hemisphere appears to be expanding, while the northern hemisphere looks like contracting. These two contract states can be confirmed by the data of space geodetic measurement. A trial explanation for the asymmetry of the Earth is delivered.
引文
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[2] JeansJH .Thevibrationandstabilityofagravitatingplanet.Roy.Soc.Lond.Phil.Trans.,A ,1902,201(1):157—184.
[3] GaposchkinEM .SmithsonianstandardEarth(III).Cambridge:SmithsonianAstrophysicalObservatorySpecialRept.,1973,(353).
[4] 马宗晋,陈 强.全球地震构造系统与地球的非对称性.中国科学,1988,B32(10):1092—1099.MAZongJin,CHENQiang.Globalseismotectonicsystemsandtheearth’sasymmetry.ScienceinChina(inChinese),1988,B33(1):121—128.
[5] PollackHN ,HunterSJ,JohnsonTR .HeatflowfromtheEarth’sinterior:analysisoftheglobaldataset.ReviewofGeo physics1993,31(3):267—280.
[6] 马宗晋,陈章立,傅征祥等.亚欧地震系的地震构造特征.中国科学,1980,B22(9):883—890.MAZongJin,CHENZhangLi,FUZhengXiangetal.Seismo tectonicfeaturesofEurasianseismicsystem,ScienceinChina(inChinese),1980,B22(9):883—890.
[7] PinetC ,JaupartC ,MareschalC ,etal.HeatflowandstructureofthelithosphereintheEasternCanadianShield.J .Geo phys,Res.,1991,96(B12):19941—19963
[8] TanimotoT .LongWavelengthS wavevelocitystructurethroughoutthemantle.Geophys.J .Int.,1990,100(2):327—336.
[9] SuWJ,WoodwardRL ,DziewonskiAM .Degree12modelofshearvelocityheterogenetyinthemantle.JGeophys.Res.,1994,99(B3):6945—6980.
[10] Gripp,AE ,RGGordon.CurrentplatevelocitiesrelativetohotspotsincorporatingtheNUVEL 1globalplatemotionmodel.Geophys.Res.Let.1990,17(8):1109—1112.
[11] DemetsC ,GordonRG ,ArgusDF ,etal,Currentplatemotion.Geophys.J.Int.,1990,101(3):425—478.
[12] 王鸿祯.地球的节律与大陆动力学的思考.地学前缘,1997,4(3):1—12WANGHongZhen.SpeculationsonEarth’srhythmsandcontinentaldynamics.EarthScienceFrontiers(inChinese),1997,4(3):1—12
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