QUESTION:
I would also like to know if the weather conditions such as winds and cloud
patterns are influenced by direct solar winds and the large amount of space
particles that must easily enter Mars' atmosphere?

ANSWER from Bruce Jakosky on November 8, 1997:
The solar wind does impinge onto the top of the Mars atmosphere.  However,
it is stopped by the atmosphere well before it gets to the surface.  The
global pattern of winds within the bulk atmosphere, and of clouds carried by
the winds, is determined by the heating that occurs below about 50 km. 
Particles from the solar wind are stopped at the top of the atmosphere, at
around 200 km altitude.

In the long run, the solar wind has the effect of stripping gas off the top
of the atmosphere, rather than adding material to it.  The processes have
been investigated at Venus, where the interactions of the solar wind with
the atmosphere are similar to those at Mars, but we have not flown
instruments to Mars that measure these properties.  The Mars Global Surveyor
in orbit at Mars now is investigating the magnetic field and the
interactions with the solar wind.  Also, the Japanese spacecraft called
Planet-B will be launched to Mars in 1998 and will investigate these
processes in detail.