A severe drought that has lasted on Earth for over two decades is now thought to have affected gravity waves where our planet’s atmosphere meets outer space.
Researchers Chester Gardner and Chiao-Yao She were studying the upper reaches of Earth’s atmosphere with LIDAR (Light Detection and Ranging) when they discovered a 30% decrease in gravity waves after the Southwestern North American (SWNA) megadrought began. This suggested that changes in the lower atmosphere can affect the upper atmosphere more than previously thought.
Gravity waves are not the same as the gravitational waves that warp spacetime. Instead, when two substances in the atmosphere are unbalanced, gravity waves develop as the forces of gravity and buoyancy equalize and create vertical waves. (When a buoyant substance rises, gravity then pulls it back down before buoyancy takes effect once more and the process repeats.) These waves take more time to transmit through denser substances like water. In the furthest expanses of the upper atmosphere, they can spread more easily (and in any direction) since the air is so thin at that altitude.
The researchers also discovered that the greatest amount of gravity wave activity happened during the winter, when powerful winds produced rain and snow, and in mid to late summer when rains swept in from the Pacific Ocean. This suggested that precipitation was a factor in gravity wave reduction. It appeared that storms had brought about gravity waves, and a decrease in precipitation during the drought meant fewer storms – and thus fewer gravity waves.
https://www.space.com/drought-on-earth-affects-space-gravity-waves