P. Rannou S. Rodriguez Christophe Sotin C.A. Griffith L. Le Corre J. W. Barnes R. H. Brown K. H. Baines B. J. Buratti Roger N. Clark P. D. Nicholson G. Tobie Stéphane Le Mouélic 2012 <p><span>Saturn's Moon&nbsp;Titan&nbsp;has a thick atmosphere with a meteorological cycle. We report on the evolution of the giant cloud system covering its north pole using observations acquired by the Visual and Infrared Mapping&nbsp;Spectrometer&nbsp;onboard the Cassini spacecraft. A&nbsp;radiative transfer&nbsp;model in spherical geometry shows that the clouds are found at an&nbsp;altitude&nbsp;between 30 and 65</span><span>&nbsp;</span><span>km. We also show that the polar cloud system vanished progressively as Titan approached&nbsp;equinox&nbsp;in August 2009, revealing at optical wavelengths the underlying sea known as Kraken Mare. This decrease of activity suggests that the north-polar downwelling has begun to shut off. Such a scenario is compared with the Titan global circulation model of&nbsp;</span>Rannou et al. (2006)<span>, which predicts a decrease of cloud coverage in northern latitudes at the same period of time.</span></p> application/pdf 10.1016/j.pss.2011.04.006 en Elsevier Dissipation of Titans north polar cloud at northern spring equinox article