CLOUD FORMATIONS OVER THE BERING SEA

FROM:  NASA 
Cloud Streets in the Bering Sea

Ice, wind, cold temperatures and ocean waters combined to created dramatic cloud formations over the Bering Sea in late January, 2015. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Aqua satellite passed over the region and captured this true-color image on Jan. 23.

The frozen tundra of Russia lies in the northwest of the image, and snow-covered Alaska lies in the northeast. Sea ice extends from the land well into the Bering Sea. Over the dark water bright white clouds line in up close, parallel rows. These formations are known as “cloud streets”.

Air blowing over the cold, snowy land and then over ice becomes both cold and dry. When the air then moves over relatively warmer and much moister water and lead to the development of parallel cylinders of spinning air. On the upper edge of these cylinders of air, where the air is rising, small clouds form. Where air is descending, the skies are clear. This clear/cloudy pattern, formed in parallel rows, gives the impression of streets.

The clouds begin over the sea ice, but they primarily hang over open ocean. The streets are neat and in tight rows closest to land, while further over the Bering Sea the pattern widens and begins to become more random. The rows of clouds are also not perfectly straight, but tend to curve. The strength and direction of the wind helps create these features: where the wind is strongest, nearest to shore, the clouds line up most neatly. The clouds align with the wind direction, so the direction of the streets gives strong clues to prevailing wind direction.  Image Credit: NASA/Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC.

NOAA OCEAN TODAY VIDEO: 'CORAL FORESTS OF THE DEEP'

NASA STUDIES INTERATIONS OF POLLUTION AND STORMS

FROM: NASA
NASA Flights Target How Pollution, Storms and Climate Mix

WASHINGTON -- NASA aircraft will take to the skies over the southern United States this summer to investigate how air pollution and natural emissions, which are pushed high into the atmosphere by large storms, affect atmospheric composition and climate.

NASA will conduct its most complex airborne science campaign of the year from Houston's Ellington Field, which is operated by the agency's Johnson Space Center, beginning Aug. 7 and continuing through September. The field campaign draws together coordinated observations from NASA satellites, aircraft and an array of ground sites.

More than 250 scientists, engineers, and flight personnel are participating in the Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. The project is sponsored by the Earth Science Division in the Science Mission Directorate at NASA Headquarters in Washington. Brian Toon of the Department of Atmospheric and Oceanic Sciences at the University of Colorado, Boulder, is SEAC4RS lead scientist.

Aircraft and sensors will probe the atmosphere from top to bottom at the critical time of year when weather systems are strong enough and regional air pollution and natural emissions are prolific enough to pump gases and particles high into the atmosphere. The result is potentially global consequences for Earth's atmosphere and climate.

"In summertime across the United States, emissions from large seasonal fires, metropolitan areas, and vegetation are moved upward by thunderstorms and the North American Monsoon," Toon said. "When these chemicals get into the stratosphere they can affect the whole Earth. They also may influence how thunderstorms behave. With SEAC4RS we hope to better understand how all these things interact."

SEAC4RS will provide new insights into the effects of the gases and tiny aerosol particles in the atmosphere. The mission is targeting two major regional sources of summertime emissions: intense smoke from forest fires in the U.S. West and natural emissions of isoprene, a carbon compound, from forests in the Southeast.

Forest fire smoke can change the properties of clouds. The particles in the smoke can reflect and absorb incoming solar energy, potentially producing a net cooling at the ground and a warming of the atmosphere. The addition of large amounts of chemicals, such as isoprene, can alter the chemical balance of the atmosphere. Some of these chemicals can damage Earth's protective ozone layer.

The mission will use a number of scientific instruments in orbit, in the air, and on the ground to paint a detailed picture of these intertwined atmospheric processes. As a fleet of formation-flying satellites known as NASA's A-Train passes over the region every day, sensors will detect different features of the scene below. NASA's ER-2 high-altitude aircraft will fly into the stratosphere to the edge of space while NASA's DC-8 aircraft will sample the atmosphere below it. A third aircraft from SPEC Inc., of Boulder, Colo., will measure cloud properties.
One benefit of this thorough examination of the region's atmosphere will be more accurate satellite data.

"By using aircraft to collect data from inside the atmosphere, we can compare those measurements with what our satellites see and improve the quality of the data from space," said Hal Maring of the Earth Science Division at NASA Headquarters.

The SEAC4RS campaign is partly supported by the U.S. Naval Research Laboratory. NASA scientists involved in the mission come from NASA's Ames Research Center at Moffett Field, Calif.; Goddard Space Flight Center in Greenbelt., Md.; Jet Propulsion Laboratory in Pasadena, Calif.; and Langley Research Center in Hampton, Va.

NASA's Earth Science Project Office at Ames manages the SEAC4RS project. The DC-8 and ER-2 research aircraft are managed by NASA's Dryden Flight Research Center and based at Dryden's Aircraft Operations Facility in Palmdale, Calif

THE ACID RAIN PROBLEM AND LEGACY

FROM:  NATIONAL SCIENCE FOUNDATION

Has acid rain washed out of forests and streams? Or is a new threat on the way?
Credit: NSF Hubbard Brook LTER Site

Acid Rain: Scourge of the Past or Trend of the Present?New connection between climate change and acidification of Northeast's forests and streams
July 25, 2012
Acid rain. It was a problem that largely affected U.S. eastern states. It began in the 1950s when Midwest coal plants spewed sulfur dioxide and nitrogen oxides into the air, turning clouds--and rainfall--acidic.

As acid rain fell, it affected everything it touched, leaching calcium from soils and robbing plants of important nutrients. New England's sugar maples were among the trees left high and dry.

Acid rain also poisoned lakes in places like New York's Adirondack Mountains, turning them into a witches' brew of low pH waters that killed fish and brought numbers of fish-eating birds like loons to the brink.

Then in 1970 the U.S. Congress imposed acid emission regulations through the Clean Air Act, strengthened two decades later in 1990. By the 2000s, sulfate and nitrate in precipitation had decreased by some 40 percent.

Has acid rain now blown over? Or is there a new dark cloud on the horizon?

In findings recently published in the journal Water Resources Research, Charles Driscoll of Syracuse University and the National Science Foundation's (NSF) Hubbard Brook Long Term Ecological Research (LTER) site in New Hampshire reports that the reign of acid rain is far from over.

It's simply "shape-shifted" into a different form.

Hubbard Brook is one of 26 NSF LTER sites across the nation and around the world in ecosystems from deserts to coral reefs to coastal estuaries.

Co-authors of the paper are Afshin Pourmokhtarian of Syracuse University, John Campbell of the U.S. Forest Service in Durham, N.H., and Katharine Hayhoe of Texas Tech University. Pourmokhtarian is the lead author.

Acid rain was first identified in North America at Hubbard Brook in the mid-1960s, and later shown to result from long-range transport of sulfur dioxide and nitrogen oxides from power plants.

Hubbard Brook research influenced national and international acid rain policies, including the 1990 Clean Air Act amendments.

Researchers at Hubbard Brook have continued to study the effects of acid rain on forest growth and on soil and stream chemistry.

Long-term biogeochemical measurements, for example, have documented a decline in calcium levels in soils and plants over the past 40 years. Calcium is leaching from soils that nourish trees such as maples. The loss is primarily related to the effects of acid rain (and acid snow).

Now Hubbard Brook LTER scientists have discovered that a combination of today's higher atmospheric carbon dioxide level and its atmospheric fallout is altering the hydrology and water quality of forested watersheds--in much the same way as acid rain.

"It's taken years for New England forests, lakes and streams to recover from the acidification caused by atmospheric pollution," says Saran Twombly, NSF program director for long-term ecological research.

"It appears that these forests and streams are under threat again. Climate change will likely return them to an acidified state. The implications for these environments, and for humans depending on them, are severe."

Climate projections indicate that over the 21st century, average air temperature will increase at the Hubbard Brook site by 1.7 to 6.5 degrees C, with increases in annual precipitation ranging from 4 to 32 centimeters above the average from 1970-2000.

Hubbard Brook scientists turned to a biogeochemical model known as PnET-BGC to look at the effects of changes in temperature, precipitation, solar radiation and atmospheric carbon dioxide on major elements such as nitrogen in forests.

The model is used to evaluate the effects of climate change, atmospheric deposition, and land disturbance on soil and surface waters in northern forest ecosystems.

It was created by linking the forest-soil-water model PnET-CN with a biogeochemical sub-model, enabling the incorporation of major elements like calcium, nitrogen, potassium and others.

The results show that under a scenario of future climate change, snowfall at Hubbard Brook will begin later in winter, snowmelt will happen earlier in spring, and soil and stream waters will become acidified, altering the quality of water draining from forested watersheds.

"The combination of all these factors makes it difficult to assess the effects of climate change on forest ecosystems," says Driscoll.

"The issue is especially challenging in small mountain watersheds because they're strongly influenced by local weather patterns."

The Hubbard Brook LTER site has short, cool summers and long, cold winters. Its forests are made up of northern hardwood trees like sugar maples, American beeches and yellow birches. Conifers--mostly balsam firs and red spruces--are more abundant at higher elevations.

The model was run for Watershed 6 at Hubbard Brook. "This area has one of the longest continuous records of meteorology, hydrology and biogeochemistry research in the U.S.," says Pourmokhtarian.

The watershed was logged extensively from 1910 to 1917; it survived a hurricane in 1938 and an ice storm in 1998.

It may have more to weather in the decades ahead.

The model showed that in forest watersheds, the legacy of an accumulation of nitrogen, a result of acid rain, could have long-term effects on soil and on surface waters like streams.

Changes in climate may also alter the composition of forests, says Driscoll. "That might be very pronounced in places like Hubbard Brook. They're in a transition forest zone between northern hardwoods and coniferous red spruces and balsam firs."

The model is sensitive to climate that is changing now--and climate changes expected to occur in the future.

In scenarios that result in water stress, such as decreases in summer soil moisture due to shifts in hydrology, the end result is further acidification of soil and water.