## Climates, seasons and cities of terraformed Mars

In a Earth-like planet, for a given distribution of land and sea, climate zones should be univocally determined. That is my hypothesis, it's pure physics! We find in the literature many fantasy worlds with deserts, rainforests, ice caps, volcanoes... however, are they in the right place?

I'm creating procedural worlds and, as a physicist, it's not just about 'looking real' but 'looking scientifically real'. I want to keep it simple and fast, so I came with a procedure to define climate areas based on simple grounds:

The model still lacks ocean currents (definitely important, Europe is warm because ocean currents) and river neither (work in progress) but it looks enough for a nice estimation of climates. When I test it on Earth (taking elevation data from NASA for instance) I got something not too far from reality, with some deviations:

Ok, not perfect: Northern Europe appears as cold as Northern Canada (but we know why), India and China looks like deserts (probably because the lack of rivers and additional wind patterns) and the Arabian Peninsula and the Horn of Africa enjoy tropical climates (I do not consider how big is the water body when obtaining distances from the ocean, and it looks like Red Sea and Persian Gulf are not big enough to cool and humidify the area). However, given the simplicity of the model, the result can be considered as satisfactory.

After this test, and after playing with NASA's elevation maps, the idea was too attractive: what if I use Mar's elevation map instead?

Let's go then! Some useful info about terraforming Mars can be found here. Mars is smaller indeed, and I'm not sure how dense the atmosphere could be in a terraformed Mars (which would affect to the prevailing winds, the lapse rate and pressure gradients). However the axial tilt is similar (for the seasons) and I lack of a better choice so let's apply the procedure with similar parameters as for Earth. These are the steps:

• I took the elevation from here. It looks like this:

• I define the sea level at z = 0.3 in relative scale. Why? When looking at the elevation distribution we find two main plates, quite similar to Earth crust (compare here). Thus I just put the sea level at the equivalent elevation. I guess that any terraform engineer can argue that exists a critical mass of water needed to keep the water cycle and thus the sea level is determined by the size of the planet and its distance to the Sun, and I would agree.

• I define prevailing winds as function of the latitude.
• I define average temperature and annual range.
• I proceed with the segmentation according to temperature and annual range.

Cool! here it is. Deserts, tropical forest, Mediterranean islands... How does it look if I paint the continents accordingly?

Let's give names!

Nice! Elysium Islands look like a nice place for holydays, and the land between Argyre and Margaritifer seas should be perfect for a Mediterranean-like lifestyle. Sabaea and Tyrrhena may hold amazing rainforests and Claritas Mountains should be great for skiing. Noctur canyons may compete with the Grand Canyon, and climbing Olympus Mountain should be reserved for the bravest.

However, since we know that the model is not perfect, here it is my list of potential inaccuracies: I expect big rivers from Tharsis mountains so probably the Tharsis Desert would be not as big. Ocean currents can also change the climate along the coast of the Margaritifer Sea, as well as at the Memnonia Sea and around Hellas Sea. The impact of Marineris Sea in the surrounding may be different as well. Apart from that, looks cool!

How it would change with seasons? Inspired on this, I created this animated gif!

Since we also have a model for city growth and road networks, I'm temped to figure out how it would like the cities in the terraformed Mars. Inspired on this, this is what to expect in terraformed Mars according to our equations:

Remarkably, the two most populated areas are Promethei and Western Noachis. Marineris sea also becomes and important demographic hub. Life in Lyor Islands exists, the northern point on Mars. That could be cool.

An infinite number of small and big stories can be written about the life in any of these cities. The daily business in the rare metal mines in the South Aonia, the complex deployment of the water supply along Tharsis Desert, patrols seeking for pirates in Elysium sea... endless.