Atmosphere

atmosphere

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

Earth-like atmosphere enough to set some exoplanets spinning

Earth is “Exhibit A” in showing that planetary rotation — which moderates global climate, keeps a lot of water in liquid form and generally makes the place more livable — is a plus when it comes to sustaining life. But scientists have thought that many of the rocky, Earth-like exoplanets discovered recently, which might otherwise be considered potentially hospitable to life, aren’t so fortunate. On these unlucky worlds, unable to rotate because they’re held too tightly by their parent stars’ gravity, one half of the planet is perpetually roasted by stellar radiation while the other is left frigid and dark. Now, however, a new study suggests that a little atmosphere can go a long way toward helping exoplanets rotate.
 

22 Aug 2015

As an aerosolizer, dust devils demoted

Dust is an inescapable byproduct of a rocky planet reworked by tectonic forces, extraterrestrial impacts and human activities. And though it may seem like a nuisance, airborne dust plays an integral role in the Earth system, fertilizing downwind ecosystems and influencing climate. But just how dust gets lofted into the air has long puzzled scientists. Previous studies have suggested that dust devils could stir up as much as a third of the atmosphere’s dust budget, but new work reveals these twisters contribute just a tenth of that amount.

01 Aug 2015

New satellite maps carbon dioxide sources and sinks in high definition

A recently launched satellite is now measuring atmospheric carbon dioxide with greater precision than ever before. Launched on July 2, the Orbiting Carbon Observatory-2 (OCO-2) is already mapping levels of carbon dioxide, the presence of which in the air constantly varies by region and over time. It has also validated a new technique of analysis that was not even contemplated when the mission was planned, according to scientists who discussed the mission at a press conference during the annual meeting of the American Geophysical Union (AGU) in San Francisco.

23 Dec 2014

Carbon tet still offensive to ozone layer

Earth’s ultraviolet light-shielding ozone layer is recovering, according to a report released in September by the World Meteorological Organization and the United Nations Environment Programme. The findings, authored by more than 250 scientists and presented as part of the latest Scientific Assessment of Ozone Depletion (SAOD), suggest the ongoing success of the 1987 Montreal Protocol and its amendments in cutting atmospheric levels of chlorofluorocarbons (CFCs) and other ozone-depleting substances (ODS’s), which have fallen by about 10 to 15 percent overall since peaking in the late 1990s.

22 Dec 2014

The Chesapeake Bay gets some good news

The Chesapeake Bay watershed is the largest on the Atlantic seaboard, encompassing most of Maryland and Virginia, along with parts of Delaware, New York, Pennsylvania and West Virginia. More than 150 rivers flow into the system, carrying pollution and nutrient runoff from a 160,000-square-kilometer area into the bay ecosystem. A new study tracking long-term effects of the Clean Air Act has some good news about the often-poor water quality in some areas of the Chesapeake Bay watershed, but the overall picture may be complicated by hydrology.

02 Apr 2014

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