Perfection said:
Oh and he still hasn't shown how to get pressure up to human acceptable levels.
In figure 1 we see the results of our model when applied to the situation at Mars' south polar cap, where it is believed that enough CO2 may be held frozen as dry ice to give Mars an atmosphere on the order of 50 to 100 mbar. We have plotted the polar temperature as a function of the pressure, in accord with equations (1) and (2), and the vapor pressure as a function of the polar temperature, in accord with equation (5). There are two equilibrium points, labeled A and B where the values of P and T are mutually consistent. However A is a stable equilibrium, while B is unstable. This can be seen by examining the dynamics of the system wherever the two curves do not coincide. Whenever the temperature curve lies above the vapor pressure curve, the system will move to the right, i.e. towards increased temperature and pressure; this would represent a runaway greenhouse effect. Whenever the pressure curve lies above the temperature curve, the system will move to the left, i.e. a temperatures and pressure will both drop in a runaway icebox icebox effect. Mars today is at point A, with 6 mbar of pressure and a temperature of about 147 K at the pole.
Now consider what would happen if someone artificially increased the temperature of the Martian pole by several degrees K. As the temperature is increased, points A and B would move towards each other until they met. If the temperature increase were
4 K, the temperature curve would be moved upwards on the graph sufficiently so that it would lie above the vapor pressure curve everywhere. The result would be a runaway greenhouse effect that would cause the entire pole to evaporate, perhaps in less than a decade. Once the pressure and temperature have moved past the current location point B, Mars will be in a runaway greenhouse condition even without artificial heating, so if later the heating activity were discontinued the atmosphere will remain in place.
As the polar cap evaporates, the dynamics of the greenhouse effect caused by the reserves of CO2 held in the Martian soil come into play. These reserves exist primarily in the high latitude regions, and by themselves are estimated to be enough to give Mars a 400 mbar atmosphere. We can't get them all out however, because as they are forced out of the ground by warming, the soil becomes an increasingly effective "dry sponge" acting to hold them back. The dynamics of this system are shown in fig. 2, in which we assume Td=20, current polar reserves of 100 mb, and regolith reserves of 394 mb, and graph the pressure on the planet as a function of Treg, where Treg is the weighted average of the temperature given by integrating the right hand side of equation (6) over the surface of the planet using the temperature distribution given by equation (4).
That is:
Treg= -Tdln{0S90Exp(-T(q)/Td)sinqdq} (Eq. 7)
Since Treg is a function of the temperature distribution and Tmean, it is a function of P, and thus Treg(P) can also be graphed. The result are a set of T(P) curves and P(T) curves, whose crossing points reflect stable or unstable equilibrium, just as in the case of the polar cap analysis.
It can be seen in fig. 2 that the atmosphere soil system under the chosen assumption of Td=20 K has only 1 equilibrium point, which is stable, and which will be overrun by the pressure generated by the vaporized polar cap. Thus, by the time the process is brought to a halt, an atmosphere with a total pressure of about 300 mbar, or 4.4 pounds per square inch, can be brought into being. Also shown in Fig. 2 is the day-night average temperature that will result in Mars' tropical regions (Tmax) during summertime. It can be seen that the 273 K freezing point of water will be approached. With the addition of modest ongoing artificial greenhouse efforts, it can be exceeded.
The assumption of Td=20 is optimistic, however, and the location of the equilibrium convergence point (point C in fig. 2) is very sensitive to the value chosen for Td. In fig.3 we show what happens if values of Td=25 and Td=30 are assumed. In these cases, the convergence point moves from 300 mb at Td=20 to 31 and 16 mb for Td=25 and Td=30 respectively. (The value of the Treg curve in fig. 3 was calculated under the assumption of Td=25; it varies from this value by a degree or two for Td=20 or 30.) Such extraordinary sensitivity of the final condition to the unknown value of Td may appear at first glance to put the entire viability of the terraforming concept at risk. However in fig 3 we also show (dotted line) the situation if artificial greenhouse methods are employed to maintain Treg at a temperature 10 K above those produced by the CO2 outgassing itself. It can be seen that drastic improvements in the final T and P values are effected for the Td=25 and 30 cases, with all three cases converging upon final states with Mars possessing atmospheres with several hundred millibars pressure.
Fig. 3 An induced 10 K rise in regolith temperature can counter effect of Td variations. Data shown assumes a planetary volatile inventory of 500 mb CO2.
In figs 4,5,6, and 7 we show the convergence condition pressure and maximum seasonal average temperature in the Martian tropics resulting on either a "poor" Mars, possessing a total supply of 500 mb of CO2 (50 mb of CO2 in the polar cap and 444 mb in the regolith), or a "rich" Mars possessing 1000 mb of CO2 (100 mb in the polar cap and 894 mb in the regolith). different curves are shown under the assumptions that either no sustained greenhouse effort is mounted after the initial polar cap release, or that continued efforts are employed to maintain the planet's mean temperature 5, 10 or 20 degrees above the value produced by the CO2 atmosphere alone. It can be seen that if a sustained effort is mounted to keep an artificial DT of 20 degrees in place, then a tangible atmosphere and acceptable pressures can be produced even if Td has a pessimistic value of 40 K.
*note all fo the graphs and chars are misisng so i guess you need to read over it all agian
and he relies on asteroids impacts for certain things, which is not the best way of going about terraforming. Oh and he still hasn't shown how to get pressure up to human acceptable levels.
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