Mars Gale Crater was chosen as the landing site for the Curiosity rover for its geologic interest, but the weather there is fascinating scientists as well.

During the first three months on Mars, the Rover Environmental Monitoring Station (REMS) detected 21 drops in atmospheric pressure coupled with a sudden change in wind direction indicating a passing whirlwind.

Unlike past missions, none of Curiosity's 17 cameras have spotted any of the mini-tornadoes moving across the landscape. Scientists theorize that the swirling winds aren't picking up much dust, making them more difficult to image.

Winds on any planet work pretty much the same way they do on Earth. Air flows to areas of lower pressure. The cause of that low pressure is very different on the red planet though.

Mars lacks a protective magnetic field like Earth's. The result is greater heating of the upper atmosphere causing it to expand on the side facing the sun. Air from the night side then flows to the day side in response to the lower pressure at the surface created by the expanding warmer air. This daily cycle has been observed by the rover since it landed in August.

Characterizing winds in Gale Crater is proving to be a challenge for researchers.

Curiosity sits at the base of a mountain in the center of Gale Crater. As the temperature changes through the day, air flows up the mountain and up the crater walls. Winds also flow around the base of the mountain creating a complex wind pattern that is fascinating scientists.

Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on twitter @rtphokie.