Formation of Jets and Equatorial Superrotation on Jupiter
Formation of Jets and Equatorial Superrotation on Jupiter
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木星上喷流的形成和赤道超自转
DOI：
10.1175/2008jas2798.1
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发表时间：
2008
影响因子：
1.3
通讯作者：
Junjun Liu
中科院分区：
文献类型：
--
作者：
T. Schneider;Junjun Liu
木星超对流层中的带状气流被组织成交替的逆时针和逆时针急流，在赤道处有一个逆时针（超旋转）急流。现有的模型认为，作为驱动器的流动，无论是差分辐射加热的大气层或内在的流量来自内部深处，但是，他们没有再现所有的大尺度特征的木星的喷流和热结构。在这里，它表明，在占木星的喷气机和热结构的困难解决，如果差分辐射加热和内在热通量的影响被认为是在一起，如果上层对流层动力学联系到磁流体动力学（MHD）的阻力，作用在大气深处，并影响zonalflowway从赤道，但不是附近。差辐射加热产生的斜压涡旋可以解释赤道外急流，内禀对流热通量产生的赤道Rossby波可以解释赤道超旋转，纬向气流向大气深处延伸，速度随深度变化，从赤道一直延伸到MHD阻力作用的深度。该理论得到了木星外层大气能量一致的大气环流模型模拟的支持。一个模拟，包括差分辐射加热和固有的热通量再现木星的观测到的喷流和热结构，并作出可测试的预测尚未观察到的方面。一个控制模拟，仅包括差分辐射加热，但没有内在的热通量producesoff-equatorialjets，但没有赤道superrotation; anothercontrol模拟，仅包括内在的热通量，但没有差分辐射加热producesoff-equatorialjets赤道superrotation，但没有。所提出的形成喷流和赤道超旋转的机制可能在所有巨行星的大气中起作用。
ThezonalflowinJupiter’suppertroposphereisorganizedintoalternatingretrogradeandprogradejets,with a prograde (superrotating) jet at the equator. Existing models posit as the driver of the flow either differential radiativeheatingoftheatmosphereorintrinsicheatfluxesemanatingfromthedeepinterior;however,theydo not reproduce all large-scale features of Jupiter’s jets and thermal structure. Here it is shown that the difficulties in accounting for Jupiter’s jets and thermal structure resolve if the effects of differential radiative heating and intrinsic heat fluxes are considered together, and if upper-tropospheric dynamics are linked to a magnetohydrodynamic(MHD)dragthatactsdeepintheatmosphereandaffectsthezonalflowawayfrombut not near the equator. Baroclinic eddies generated by differential radiative heating can account for the offequatorial jets; meridionally propagating equatorial Rossby waves generated by intrinsic convective heat fluxescanaccountfortheequatorialsuperrotation.Thezonalflowextendsdeeplyintotheatmosphere,withits speed changing with depth, away from the equator up to depths at which the MHD drag acts. The theory is supported by simulations with an energetically consistent general circulation model of Jupiter’s outer atmosphere. A simulation that incorporates differential radiative heating and intrinsic heat fluxes reproduces Jupiter’s observed jets and thermal structure and makes testable predictions about as yet unobserved aspects thereof. A control simulation that incorporates only differential radiative heating but not intrinsic heat fluxes producesoff-equatorialjetsbutnoequatorialsuperrotation;anothercontrolsimulationthatincorporatesonly intrinsic heat fluxes but not differential radiative heating produces equatorial superrotation but no offequatorial jets. The proposed mechanisms for the formation of jets and equatorial superrotation likely act in the atmospheres of all giant planets.