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atmosphere

Earth's largest jet stream unexpectedly disrupted

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.

06 Jan 2017

Smokier U.S. West as climate changes

Extended wildfire seasons and larger and more frequent burns will likely be the consequence of the hotter and drier conditions expected to result from climate change. New research shows that this expected surge in wildfires also poses a growing threat to human health.

11 Dec 2016

Cloud feedbacks drive climate sensitivity

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.

17 Nov 2016

Newly discovered Earth-like worlds are rocky, not gassy

In May, a new planetary system was discovered just 40 light-years from Earth, including three Earth-sized planets orbiting around their red dwarf sun in a temperature range that could potentially harbor life. Now, a follow-up study on the system has found that the two innermost planets are primarily rocky with compact atmospheres, as opposed to inhospitable gas giants, like Jupiter.

15 Nov 2016

Clouds can form without particles

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.

30 Sep 2016

Rainbows reclassified

Rainbows — those arches of color that streak across wet skies — are recognizable to almost everyone. Our understanding of rainbows, though, particularly how they form and the diversity of shapes they can take, is still fuzzy.

21 Dec 2015

Is aviation 'whitening' the sky?

Clear blue skies may not be as clear as they appear. Skies are actually becoming less clear, causing incoming sunlight to scatter in different directions, rather than striking the planet directly — and aviation may be to blame, according to research presented this week at the fall meeting of the American Geophysical Union (AGU) in San Francisco.

17 Dec 2015

Marine microorganisms drive summer clouds over Southern Ocean

The Southern Ocean surrounding Antarctica is home to some of the most pristine air anywhere on Earth. And yet it’s also one of the cloudiest places on the planet, a seeming contradiction because water droplets require particulate matter in the air to condense into clouds. Now, a study looking at cloud droplet concentrations over the Southern Ocean is giving scientists a clearer understanding of the role played by marine microorganisms in cloud formation and climate.
 
06 Nov 2015

Santa Ana winds get a fiery boost from the stratosphere

Southern California’s Santa Ana winds have long been implicated in the region’s dangerous and destructive wildfires. Now, a new study in Geophysical Research Letters points the finger at an accomplice: a phenomenon called stratospheric intrusions, which are natural atmospheric events that bring warm, dry air from the upper atmosphere down to the surface. These intrusions may exacerbate fires, as well as the region’s infamously bad air pollution.
 
23 Oct 2015

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