[X] My Assistant

[SigurRosFan]

--- This climate model also allows scientists to predict the cloud distribution for the complete Titan year (30 terrestrial years), and especially in the next years of Cassini observations.

The observed south polar cloud appears at the top of a particular ‘Hadley cell’, or mass of vertically circulating air, exactly where predicted at the south pole at an altitude of around 20-30 kilometres. ---

http://www.esa.int/esaCP/SEMAXTMZCIE_index_0.html - Predicting the weather on Titan?

[volcanopele]

--- This climate model also allows scientists to predict the cloud distribution for the complete Titan year (30 terrestrial years), and especially in the next years of Cassini observations.

The observed south polar cloud appears at the top of a particular ‘Hadley cell’, or mass of vertically circulating air, exactly where predicted at the south pole at an altitude of around 20-30 kilometres. ---

http://www.esa.int/esaCP/SEMAXTMZCIE_index_0.html - Predicting the weather on Titan?

Interesting model. However, they didn't put a convective cloud model into their climate model. Most of the clouds we see are convective cloud cells. So they predict clouds in the "right" locations but not the correct types of clouds. So one has to be very careful when interpreting their results.

The second problem with their model is that they predict a decrease in clouds at 40S as we near equinox. This is what we observe. However, they predict no apparent decrease in cloud activity at the poles, where we have seen an overall decrease (but not a complete absence) in the last year.

[ljk4-1]

SATURN DAILY

- Titan Reveals New Complexities

http://www.spacedaily.com/reports/Titan_Re...mplexities.html

Pasadena CA (SPX) Feb 15, 2006 - This new view of Titan reveals structure in the
moon's complex atmosphere. The geometry of the Cassini spacecraft's view of
Titan during this flyby was similar to that of Voyager 1's pass in 1980.

[belleraphon1]

All...

I am reviving this thread because of the paper "Near-surface winds at the Huygens site on Titan: interpretation by means of a general circulation model" by Tetsuya Tokano due to be published in Planetary and Space Science.

ABSTRACT

"This study aims at interpreting the zonal and meridional wind in Titan's troposphere measured by the Huygens probe by means of a general circulation model. The numerical simulation elucidates the relative importance of the seasonal variation in the Hadley circulation and Saturn's gravitational tide in affecting the actual wind profile. The observed reversal of the zonal wind at two altitudes in the lower troposphere can be reproduced with this model only if the near-surface temperature profile is asymmetric about the equator and substantial seasonal redistribution of angular momentum by the variable Hadley circulation takes place. The meridional wind near the surface is mainly caused by the meridional pressure gradient and is thus a manifestation of the Hadley circulation. Southward meridional wind in the PBL (planetary boundary layer) is consistent with the near-surface temperature at the equator being lower than at mid southern latitudes. Even small changes in the radiative heating profile in the troposphere can substantially affect the mean zonal and meridional wind including their direction. Saturn's gravitational tide is rather weak at the Huygens site due to the proximity to the equator, and does not clearly manifest itself in the instantaneous vertical profile of wind. Nevertheless, the simulated descent trajectory is more consistent with the observation if the tide is present. Because of a different force balance in Titan's atmosphere from terrestrial conditions, PBL-specific wind systems like on Earth are unlikely to exist on Titan"

To paraphrase... seasonal variation in temperatures help generate strong easterlies near the surface.
A warmer southern hemisphere in the current seasonal regime favors the insolation hypothesis for generation of convective clouds. A seasonal reversal of the Hadley cell and the strong exchange of angular momentum could impact the seasonal length of day. The strength of seasonality could be dependant on how much sunlight penetrates to the surface and how asymmetric the surface temperature becomes during the solstice.

Month by month the northern regions are coming into view.... and can hardly wait for the southern RADAR SAR later this year.... what affect has 7 plus years of direct solar insolation had on weather and the surface erosion if those polar storms were the norm.

And what WILL the solstice bring... 2009 onwards should be an interesting time for the equator and seasonal change... Wish CASSINI could last the entire seasonal cycle.


Craig

[belleraphon1]

All...

Titan drizzle over western Xanadu in morning light...

abstract on ScienceExpress
Ádámkovics et al., “Widespread Morning Drizzle on Titan”
http://www.sciencemag.org/cgi/content/abstract/1146244

and

http://www.centauri-dreams.org/?p=1509

Craig