Observation of a tilt of Titan's middle-atmospheric superrotation
Observation of a tilt of Titan's middle-atmospheric superrotation
复制标题
土卫六中层大气超级自转倾斜的观测
DOI：
10.1016/j.icarus.2008.05.014
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发表时间：
2008
期刊：
影响因子：
3.2
通讯作者：
Conor A. Nixon
中科院分区：
文献类型：
--
作者：
R. Achterberg;B. Conrath;P. Gierasch;F. Flasar;Conor A. Nixon
土卫六中层大气中的恒压表面上的等温线地图环绕着两极，但显示出偏移，这意味着平均纬向流具有相对于固体旋转轴倾斜的对称轴。这种影响在两个半球都可以看到，围绕着一个一致的轴。温度场的周期图分析表明，波数1，对应于自旋倾斜的信号，是最强的波分量。我们推测，大气自旋的倾斜是由于流动和太阳加热之间的反馈。自转会自我调整，使自转赤道与朝向太阳的方向对齐，从而最大化纬向环流将角动量向上泵送以产生超自转的效率。
Maps of isotherms on surfaces of constant pressure in Titan's middle atmosphere encircle the poles but show an offset, implying that the mean zonal flow has an axis of symmetry that is tilted relative to the spin axis of the solid body. The effect is seen in both hemispheres around a consistent axis. Periodogram analysis of the temperature field shows that wavenumber one, the signal corresponding to the spin tilt, is the strongest wave component. We conjecture that the tilt of the atmospheric spin is due to a feedback between the flow and the solar heating. The spin adjusts itself to align the spin equator with the direction toward the Sun, and thereby maximizes the efficiency with which the meridional circulation pumps angular momentum upward to generate superrotation.