Atmosphere

With two rovers patrolling the surface of Mars, six spacecraft orbiting above it, and scientists here on Earth studying the Red Planet from afar, new findings are announced often. Here are a few of the latest updates.

In early 2016, scientists first noticed an unexpected change in wind direction in the stratosphere some 25 kilometers above the equator. This shift signaled the beginning of a multimonth disruption of one of the most regular atmospheric phenomena known — the quasi-biennial oscillation (QBO). The disruption is the first such event observed in this system since record keeping began in the 1950s.

Fly over the tropical or subtropical oceans and you’ll see a white blanket of clouds covering the blue-green water. These low clouds, typically forming less than 2 to 3 kilometers above the ocean surface and covering up to 40 percent of Earth’s surface, play a critical role in the planet’s energy balance. Now, new research using satellite data and climate models to investigate how these clouds respond to climate change shows that they play a large role in regulating climate sensitivity.

In addition to their aesthetic and photogenic appeal, clouds play a crucial role in Earth’s climate and ecosystems, helping regulate temperatures by reflecting sunlight. All clouds — from fluffy cumulus to wispy cirrus — grow from seeds that, more often than not, are tiny particles of pollen, dust or chemical aerosols that float into the atmosphere from Earth’s surface. Sulfuric acid, a byproduct of volcanic eruptions and fossil fuel combustion, is one of the most ubiquitous precursors to atmospheric aerosols today and has long been thought to play a major role in modern cloud formation. But what about earlier in Earth’s history, before humans impacted the atmosphere as much? Three new studies, representing both experimental and field data, suggest that the planet’s plants and trees might have done just fine on their own pumping cloud-forming aerosols into the skies.