Martian Air Pressure, How much variance is there? Options

[nprev]

Just thinking when looking at the Victoria pics...how much does the average air pressure increase with respect to the surrounding area at the bottom of the crater? Also, where is the lowest point on Mars (which also presumably has the highest air pressure)? I can't remember if it's in Hellas or Coprates Chasma.

Rationale here is that, given MRO's astonishing capabilities, these low areas should be given priority for long-term monitoring; if transient surface water exists anywhere, it's probably way down in a crater or a canyon.

[ngunn]

Just thinking when looking at the Victoria pics...how much does the average air pressure increase with respect to the surrounding area at the bottom of the crater? Also, where is the lowest point on Mars (which also presumably has the highest air pressure)? I can't remember if it's in Hellas or Coprates Chasma.

Rationale here is that, given MRO's astonishing capabilities, these low areas should be given priority for long-term monitoring; if transient surface water exists anywhere, it's probably way down in a crater or a canyon.

A very quick and simplistic response: Negligible difference over depth of Victoria. Globally? The atmospheric scale height is about 11km, of the same order as the height difference between Hellas and Olympus Mons, so a pressure and density ratio of about 2 or 3. I think that liquid water would be VERY transient, even in the most favoured spots.