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Hi everyone,
I would like to ask whether or not there are numercial climate models for martian atmosphere to simulate terraforming in this global scale?
even current super computers can't really forecast the weather accurately for the next several days.
I'm just curious how this had been done or how you could do this today. If you can just take the models used for earth atmosphere and change some parameters and can use it for mars and terraforming approaches.
best regards,
Andreas
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You're taking the wrong approach. Weather modelling does not help with terraforming. NASA does attempt weather prediction on Mars, but that's different than terraforming. They want to know if/when a global dust storm will kick up. Mariner was the first orbiter around Mars, but when it arrived the planet was engulfed in a dust storm. The orbiter couldn't see anything but dust clouds for several months. NASA doesn't want that again. So when do dust storms happen? Well, it turns out Mars weather is quite different than Earth. When the planet gets warm, dry ice sublimates to add significant quantity of CO2 to the atmosphere. Increased atmospheric volume causes a high pressure zone. Plus there are usual weather warming effects, but no oceans to moderate temperature. The result is occasionally temperature increases to create a dust storm, and when it occurs the process often cascades to engulf the planet.
But terraforming is different. We need to warm the planet sufficiently to permanently sublimate all dry ice. That will add all that mass of CO2 to the atmosphere. Dr. Chris McKay did the first work to numerically model this. He proposed deliberately causing global warming in Mars. This will require several full size chemical factories to spew massive quantities of greenhouse gasses. He numerically modelled it, and found it could be done. A couple other scientists estimated what the pressure on Mars would be; one estimated 200 millibar surface pressure, the other 300 millibar. Mars Pathfinder measured Mars surface pressure between 6.77 and 7.08 millibar, depending on weather. Earth has 1013.25 millibar at sea level, but higher altitude can be lower. That means just warming Mars can increase pressure from 0.7% that of Earth to 30% that of Earth. That would be enough for a human to walk on the surface without a spacesuit. It would be a CO2 atmosphere, so settlers would require an oxygen mask, but that's a lot better than a spacesuit.
Sublimating dry ice requires increasing surface temperature above -79°C. Yup, "above" -79°C. That has to be achieved at the poles, in winter, so the coldest spot on Mars never drops below that. If any location does, the atmosphere will freeze out as dry ice. But CO2 is a greenhouse gas itself, so releasing powerful artificial greenhouse gasses can leverage much more quantity of CO2. At some point the temperature passes a "tipping point", becoming self sustaining.
Increasing temperature further to melt water ice will release liquid water. That means rain, rivers and streams, and seas on Mars. Most importantly, it also means clouds and humidity. Water is also a greenhouse gas, so reaches a second tipping point. Once there's a water cycle, lakes and seas will moderate the temperature and again it becomes self sustaining.
Telescopes can see a polar ice cap on the north pole, but ground penetrating radar discovered a larger ice cap at the south pole, just covered by a skiff of dirt. It extends to 60° latitude and is 3.7km thick! It's so pure it isn't permafrost, it's a polar ice cap. If that south polar ice alone were melted, it would produce enough water to cover the entire planet Mars 11 metres deep. But it wouldn't cover the planet evenly, tops of mountains would stay dry while water in low lying areas would be deeper. And that's just the south pole, that doesn't count the north polar ice cap, or glaciers they have found in craters, or permafrost they have confirmed in the ground. It looks like there's enough water to fill the ancient ocean basin in the northern hemisphere; perhaps not to the same depth, but filled to it's shoreline.
All this is general and not numerical. If you want all the detail, there is one textbook on Terraforming. Get "Terraforming: Engineering Planetary Environments" by Martyn J. Fogg. You can get a used copy from Amazon.com. (expletive! The price went up!) The book is out of print, so used copies are the only ones available. I got mine new when it was still in print, it was the cost of a normal hard cover book.
http://www.amazon.com/Terraforming-Engi … 1560916095
Last edited by RobertDyck (2012-08-14 17:12:30)
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