How Do Desert Inhale and Exhale Water Vapor?

Deserts have a fascinating mechanism known as "sand breathing" or "desert breathing" that involves the inhalation and exhalation of water vapor. This phenomenon is related to the movement of air and sand within the desert environment.

The movement of wind over dunes creates imbalances in air pressure, resulting in the exchange of air with the sand. This phenomenon, known as "sand breathing," enables the survival of microorganisms in extremely dry dunes. The researchers observed that the infiltration of vapor is slower in dry sand, while wind generates internal air currents that facilitate the transportation of moisture. These currents' intensity varies based on the dune's location, wind speed, and direction.

 

When dry sand is blown across a dune, rapid fluctuations in surface moisture generate waves of humidity that penetrate downwards. Analysis suggests that the evaporation of water from individual sand grains resembles a gradual chemical reaction. Interestingly, the exchange of moisture with the atmosphere is not solely driven by differences in humidity, as current models assume, and is weaker than predicted.