Angular momentum exchange between the atmosphere/hydrosphere and interior of Saturn's moon Titan and its influence on Titan's rotation

土星最大的卫星泰坦拥有稠密的大气层和碳氢化合物的水文循环。因此，通过与地球类比，可以预计大气层和水圈的重新分布和运动会导致自转速度的时间变化和自转轴的摆动。卡西尼号航天器最近的观测首次证明了泰坦的大变量旋转，正如理论上预测的那样，并为研究地球物理流体和内部之间的机械耦合提供了可能性。该项目的目的是对土卫六大气层/水圈与内部之间的角动量交换以及土卫六在季节时间尺度上的旋转反应进行全面和定量评估。大气运动和质量负荷以及碳氢化合物水文学，如降水和极地湖泊的存在所暗示的，将被量化。考虑到不同的内部模型，角动量转移的敏感性，在内部的内部耦合进行了研究。模型结果将与卡西尼号正在进行的大地测量进行比较，以限制土卫六的大气角动量预算，但限制得很差。

Saturn’s largest moon Titan possesses a dense atmosphere and a hydrological cycle with hydrocarbons. Therefore, temporal variation in the rotation rate and wobble of the rotational axis by the redistribution and motion of the atmosphere and hydrosphere can be expected by analogy with the Earth. Recent observations by the Cassini spacecraft show first evidence of a large variable rotation of Titan as theoretically predicted and open the possibility to investigate the mechnical coupling between the geophysical fluid and interior. This project aims at comprehensive and quantiative assessment of the exchange of angular momentum between the atmosphere/hydrosphere and the interior of Titan and the rotational response of Titan on seasonal timescales. Atmospheric motion and mass loading together with hydrocarbon hydrology, as implied by the precipitation and the existence of polar lakes, will be quantified. The sensitivity of the angular momentum transfer to the internal coupling in the interior will be investigated considering different interior models. Model results will be compared with ongoing geodetic measurements by Cassini to constrain the yet poorly constrained atmospheric angular momentum budget of Titan.