Griffith C A, Penteado P, Rannou P, Brown R, Boudon V, Baines K H, Clark R, Drossart P, Buratti B, Nicholson P, McKay C P, Coustenis A, Negrao A, Jaumann R
Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, 85721 USA.
Science. 2006 Sep 15;313(5793):1620-2. doi: 10.1126/science.1128245.
Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal the presence of a vast tropospheric cloud on Titan at latitudes 51 degrees to 68 degrees north and all longitudes observed (10 degrees to 190 degrees west). The derived characteristics indicate that this cloud is composed of ethane and forms as a result of stratospheric subsidence and the particularly cool conditions near the moon's north pole. Preferential condensation of ethane, perhaps as ice, at Titan's poles during the winters may partially explain the lack of liquid ethane oceans on Titan's surface at middle and lower latitudes.
卡西尼号的可见光和红外绘图光谱仪所获得的光谱显示，在土卫六北纬51度至68度以及所有观测到的经度范围（西经10度至190度）存在一片广阔的对流层云。所推导得出的特征表明，这片云由乙烷构成，是平流层下沉以及月球北极附近特别寒冷的条件所导致的结果。冬季时，乙烷在土卫六两极优先凝结，可能是以冰的形式，这或许可以部分解释为何土卫六中低纬度地区的表面缺少液态乙烷海洋。
