titan weather: mid-lats dry, more lakes near poles

California Institute of Technology researchers have formulated successful model of Titan's weather, reports Daily Galaxy.  Professor Tapio Schneider states new model explains many features of Titan's weather. The story's short version: researchers determined summers in northern latitudes are longer but further away from sun, so water evaporates less than in shorter more intense summers of south lats.

"Schneider says the team's simulations were able to reproduce the distribution of clouds that's been observed—which was not the case with previous models. The new model also produces the right distribution of lakes. Methane tends to collect in lakes around the poles because the sunlight there is weaker on average, he explains. Energy from the sun normally evaporates liquid methane on the surface, but since there's generally less sunlight at the poles, it's easier for liquid methane there to accumulate into lakes.


But then why are there more lakes in the northern hemisphere? Schneider points out that Saturn's slightly elongated orbit means that Titan is farther from the sun when it's summer in the northern hemisphere. Kepler's second law says that a planet orbits more slowly the farther it is from the sun, which means that Titan spends more time at the far end of its elliptical orbit, when it's summer in the north.


As a result, the northern summer is longer than the southern summer. And since summer is the rainy season in Titan's polar regions, the rainy season is longer in the north. Even though the summer rains in the southern hemisphere are more intense—triggered by stronger sunlight, since Titan is closer to the sun during southern summer—there's more rain over the course of a year in the north, filling more lakes."

The intense interest in Titan, most Earth-like body in Solar System, brings question of how long before there's a mission?  JPL says the earliest date is 2018!