Astronomically forced climate changes on Saturn moon Titan

天文强迫土卫六上的气候变化

• 批准号: 262022543
• 负责人: Dr. Tetsuya Tokano
• 金额: --
• 依托单位: Applied Physics Laboratory
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/262022543?language=en
• 关键词: Astronomically; forced; climate; changes; Saturn

The study shall examine in detail the role of hydrocarbon seas in astronomically forced climate variations on Saturn moon Titan. Seas on Titan are strongly concentrated in the northern polar region, while most basins in the southern polar region are not filled with liquids. This observation led to controversial discussions as to whether the polar seas may represent analogues of ice sheets on Earth, which wax and wane with the Croll-Milankovitch cycle. A regional-scale and global-scale numerical model of methane hydrology will be used to investigate the impact of orbital parameter variations on the global sea distribution and its feedback to the climate. The major working hypothesis of the study is that the mean sea level changes on timescales of the apsidal precession of Saturn due to variable precipitation, evaporation and global transport of methane in the atmosphere. On a regional basis a 3-dimensional ocean circulation model of Titan seas will be applied to investigate how orbital forcing affects circulation and stratification in the seas. These especially include wind-driven circulation and density-driven circulation, which are relevant for variations in the sea surface temperature, sea composition and evaporation. The secular sea level change will be calculated by extrapolating annual sea level changes predicted by a series of simulations run under the orbital parameters of selected epochs in the past. On a global basis a 3-dimensional general circulation model with a built-in atmospheric hydrology scheme and simplified ocean model will be applied to simulate the continuous change in the global sea distribution. The global model particularly addresses the question as to whether polar seas in one hemisphere can expand at the expense of seas in the opposite hemisphere within an orbital cycle or there may be a trend for a preferential accumulation of seas in one of the two hemispheres for geographic or astronomical reasons. Furthermore, the feedback of the variable or invariable sea distribution on the atmospheric part of the climate will be explored by comparing the model predictions with those of a control simulation without seas.

这项研究将详细审查碳氢化合物海洋在土星卫星泰坦上天文学强迫气候变化中的作用。泰坦上的海洋强烈集中在北方极地地区，而南极地区的大多数盆地都没有充满液体。这一观察结果引发了有争议的讨论，即极地海洋是否可能代表地球上冰盖的类似物，这些冰盖随着Croll-Milankovitch循环而增加和减少。将使用区域尺度和全球尺度的甲烷水文数值模型来研究轨道参数变化对全球海洋分布的影响及其对气候的反馈。这项研究的主要工作假设是，由于降水量、蒸发量和大气中甲烷的全球运输量的变化，平均海平面在土星拱点岁差的时间尺度上发生变化。在区域基础上，将应用土卫六海洋的三维海洋环流模型来研究轨道作用力如何影响海洋的环流和分层。其中特别包括风驱动的环流和密度驱动的环流，它们与海面温度、海洋成分和蒸发的变化有关。长期海平面变化的计算方法是，根据过去选定时期的轨道参数进行的一系列模拟所预测的海平面年变化进行外推。在全球范围内，将采用一个内置大气水文方案和简化海洋模式的三维大气环流模式，模拟全球海洋分布的持续变化。全球模式特别处理的问题是，在一个轨道周期内，一个半球的极地海洋是否会以另一个半球的海洋为代价而扩大，或者由于地理或天文原因，可能存在海洋优先聚集在两个半球之一的趋势。此外，将通过比较模式预测与无海洋控制模拟的预测，探讨海洋分布对气候大气部分的反馈。

项目成果

Modeling of Seasonal Lake Level Fluctuations of Titan's Seas/Lakes

泰坦海洋/湖泊季节性湖泊水位波动的建模

• DOI: 10.1029/2018je005898
• 发表时间: 2019
• 期刊: Journal of Geophysical Research: Planets
• 作者: Tokano;Lorenz
• 通讯作者: Lorenz

A model intercomparison of Titan's climate and low-latitude environment

• DOI: 10.1016/j.icarus.2019.05.031
• 发表时间: 2019-11
• 期刊: Icarus
• 影响因子: 3.2
• 作者: J. Lora;T. Tokano;J. Vatant d'Ollone;S. Lebonnois;R. Lorenz

Eclipse-induced changes of Titan's meteorology at equinox

日食引起的土卫六春分气象变化

• DOI: 10.1016/j.pss.2016.01.001
• 发表时间: 2016
• 期刊: Planetary and Space Science
• 影响因子: 2.4
• 作者: Tokano

Nitrogen condensation in Titan’s atmosphere under contemporary atmospheric composition

现代大气成分下泰坦大气中的氮凝结

• DOI: 10.1016/j.icarus.2017.02.005
• 发表时间: 2017
• 期刊: Icarus
• 影响因子: 3.2
• 作者: Tokano

Variations in Titan’s dune orientations as a result of orbital forcing

• DOI: 10.1016/j.icarus.2015.11.036
• 发表时间: 2016-05
• 期刊: Icarus
• 影响因子: 3.2
• 作者: G. McDonald;A. Hayes;R. Ewing;J. Lora;C. Newman;T. Tokano;A. Lucas;A. Soto;Gang Chen