Mars - A Natural Atmospheric Laboratory

Mars is a perfect laboratory for investigating weather and climate. The study of these areas on the surface of Mars may lead to a better understanding of weather patterns and climate trends and conditions on the surface of the Earth.

Mars has no oceans (and therefore no ocean currents) to complicate its weather phenomena. On Earth, there are three global air circulation cells in each of the northern and southern hemispheres. Mars seems to have only a single global atmospheric circulation cell in each hemisphere of its two hemispheres. The relative simplicity of the Martian atmosphere can yield important clues to the fundamental dynamics of the Earth's atmosphere.

Primary atmospheric circulation cells on Earth and Mars

Figure 3: The Earth has three primary atmospheric circulation cells in the Northern and Southern hemisphere whereas Mars seems to have only one. The red arrows indicate zones of low atmospheric pressure and the blue arrows indicate zones of high atmospheric pressure. Note: The scale has been greatly exaggerated to show the wind circulation.

The energy from the Sun is responsible for all weather phenomena, both on Mars and on the Earth. The length of the day on Mars is almost exactly the same as the length of the day on Earth and by a remarkable coincidence, the rotational axis of Mars is tilted at approximately 25° to its orbital plane, very close to the 23° tilt of the Earth's to its orbital plane. Mars has two seasons – summer and winter – but a Martian year is almost two Earth years in duration.

Rotational Axis of Mars

Figure 4: The rotational axis of Mars is tilted 25.2 degrees away from the perpendicular to the ecliptic causing seasons in the same way that seasons are produced on Earth.

Rotational Axis of Earth

Figure 5: The rotational axis of the Earth is tilted 23.4 degrees away from the perpendicular to the ecliptic.

There is some evidence that Mars was once wetter and warmer than at the present time. We are interested in why the temperature and precipitation patterns have changed and whether there are any applications of this information which would help us to understand our own fragile environment.