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REMS pressure

Credit: NASA/JPL-Caltech.

Above are the pressure data from Curiosity's REMS sensor for the first 200 sols at Gale crater.

At about sol 170 Mars was at perihelion and a month later it was southern summer solstice and you can see the influence of the sublimation of the polar dry ice cap on the global pressure,

With the Mars Atmosphere Model I calculated that at Curiosity's landing site with an elevation of minus 4500 m. the pressure would be about 1096 Pa, considerably higher than the REMS measurements.
The difference could be caused by the near surface temperature of around zero at the time while I think the model takes much lower temperatures into account.

Because both the near surface temperature and the time of the year (because of the sublimation of the south polar ice cap) appear to have a big influence on the atmospheric pressure, isn't there an atmospheric pressure model for Mars that takes those factors into account ?

So please no complex computer program, but a model with some simple equations.

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    $\begingroup$ Fascinating question! $\endgroup$
    – uhoh
    Aug 5, 2021 at 21:40

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Climate modelling is a complicated field. As you indicate in your question, a representative model will need to take into account variations in temperature and season, but also a multitude of other parameters.

Thankfully there are readily available models that have been developed by the scientific community and validated from observational data. One example is the Mars Climate Database. You can access a web version of this here: http://www-mars.lmd.jussieu.fr/mcd_python/

We can use this model to check how the atmospheric pressure on Mars is expected to vary throughout the Mars year (i.e. with varying solar longitude and hence season) and at a specific location. I’ve used the Curiosity landing site as an input to generate the plot below (-4.5N, 137.4 E) which provides the expected atmospheric pressure 1 m above the surface at local noon with the average solar year model. We can see that this agrees reasonably well with the REMs data considering that Curiosity landed on 5th August 2012 (corresponding to a solar longitude of about 150 deg).

enter image description here

I recommend you try this for yourself. You can play around with the inputs to generate all kinds of figures for different parameters and at different locations and conditions.

I’m aware that this answer does not satisfy your request for some simple equations, but hopefully it provides a useful resource that you can use to get some further answers to your investigation!

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Yes, there are models that take into account the seasonal and temperature variations on Mars to simulate the atmospheric pressure. These models use data from spacecraft observations and measurements, as well as computer simulations, to create a detailed representation of the Martian atmosphere. They take into account factors such as the variation in solar radiation, the movement of dust and water vapor, and the changing patterns of atmospheric circulation. These models are important for understanding the dynamics of the Martian atmosphere and for predicting weather patterns on the planet.

One such model is the Mars Global Climate Model (MarsGCM), which is developed by NASA's Goddard Space Flight Center. It simulates the atmosphere, dust, and water vapor cycles on Mars and their interactions with the surface and subsurface. The model also includes radiation from the sun, as well as the effects of dust and water vapor on the planet's temperature and atmospheric pressure.

Another model is the European Space Agency's Mars Climate Database (MCD), which provides detailed simulations of the Martian atmosphere, including temperature, pressure, wind, and dust. The MCD takes into account the effects of the planet's obliquity, or tilt of its axis, which causes significant changes in the planet's climate.

These models are also used to predict future weather patterns on Mars, including changes in temperature and atmospheric pressure, as well as dust storms, which can have a significant impact on the planet's climate. These predictions are important for planning future missions to Mars and for understanding the planet's potential for supporting life.

Overall, there are various atmospheric pressure models that take into account the different temperatures and seasons on Mars. These models are developed by different institutions and organizations and are used for different purposes like predicting the weather, understanding the dynamics of the Martian atmosphere and planning the future missions.

Sources for these atmospheric pressure models include:

  • Data from spacecraft observations and measurements, such as NASA's Mars Reconnaissance Orbiter, Mars Atmosphere and Volatile Evolution (MAVEN) mission, and European Space Agency's Mars Express.
  • Computer simulations that incorporate the physical processes that govern the Martian atmosphere, such as atmospheric dynamics, radiation, and dust and water vapor cycles.
  • Laboratory experiments and field observations that provide information about the properties of Martian dust and water vapor, as well as the interactions between these materials and the atmosphere.
  • Theoretical models that describe the behavior of the Martian atmosphere and its interactions with other components of the planet, such as the surface and subsurface.
  • Observations of the planet's weather patterns, such as temperature, pressure, and wind, which are used to validate the models and improve their accuracy.

Some examples of the sources that provide data to MarsGCM are:

  • NASA's Mars Reconnaissance Orbiter, which has been observing the Martian atmosphere since 2006 and has provided data on temperature, pressure, dust, and water vapor.
  • MAVEN mission that has been measuring the upper atmosphere of Mars since 2014, providing data on the loss of atmospheric gases to space and the processes that control the planet's climate.
  • Mars Express mission, which has been observing the planet's atmosphere and surface since 2004, providing data on temperature, pressure, and dust.

The MCD is built using data from various sources including:

  • Mars Express mission, which has been providing data on the Martian atmosphere and weather patterns since 2004.
  • Mars Reconnaissance Orbiter, which has been providing data on the planet's surface and atmosphere since 2006.
  • Viking missions that were launched in 1975 and landed on Mars in 1976, providing data on the planet's surface and atmosphere.
  • Data from other spacecraft and Earth-based observations of Mars, such as observations from the Hubble Space Telescope and ground-based telescopes.
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  • $\begingroup$ Thank you for this extensive answer. Could you provide the links to the different models and are there web versions of them that are user-friendly ? $\endgroup$
    – Cornelis
    Jan 23, 2023 at 16:18

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