These images compare averaged yearly nitrogen dioxide concentrations over the Ohio River Valley region from 2005 [top] to 2011 [bottom]. Image credit: NASA Goddard’s Scientific Visualization Studio/T. Schindler
Editor’s Note: This is an excerpt from the NASA Earth Science in the News column published in the May/June issue of The Earth Observer newsletter. You can download the current issue here.
See NASA’s Dazzling Proof that U.S. Air Quality Has Improved, Mashable.com. Summer in the U.S. is the time of year when humidity skyrockets, air stagnates, and the air quality deteriorates, especially downwind of the coal-fired power plants and manufacturing plants of the Ohio Valley. During hazy and hot summer days in the big cities along the Interstate 95 corridor, the sky often looks like the visual equivalent of white noise—with the horizon indistinguishable from the milky sky. Yet air quality has actually been steadily improving over the past few years, largely thanks to the Clean Air Act, along with a drop in coal use and dramatic changes in vehicle fuel efficiency and emissions. NASA has released beautiful images demonstrating that people in major U.S. cities from Los Angeles to New York are breathing less nitrogen oxide. The data come from the Ozone Monitoring Instrument (OMI) aboard NASA’s Aura satellite. Nitrogen dioxide is one of the six common pollutants the EPA regulates to protect human health. It can harm the respiratory system and also combines with other pollutants to form smog. Nitrogen dioxide is mostly produced by burning gasoline in vehicle engines and from burning coal. “While our air quality has certainly improved over the last few decades, there is still work to do—ozone and particulate matter are still problems,” said atmospheric scientist Bryan Duncan.
Water Weight Used to Calculate the Amount of Snow in California with GPS, Scientific American. Water weighs about 8.3 pounds per gallon (1 kg/L). Now, scientists have developed a way to use water’s weight to measure just how much snow is covering mountains in the western U.S. In states like California, currently in the midst of a crippling drought, the more water managers know about how much snow is in the mountains, the better they can plan for the summer months ahead. More accurate information about such snowpack can help these managers and hydrologists plan for how to fill reservoirs, how much water they might have available during the dry season, and how dry the soils might be during fire season. They’ll also get a better fix on future levels of reservoirs for hydroelectric power generation. Donald Argus, a research scientist and geophysicist at JPL, recently published a study outlining the new technique in the journal Geophysical Research Letters. If scientists know the height of a piece of land in summertime, and the height when snow covers it, they can use the difference to calculate how much snow is sitting on the mountains. The technique uses a dense network of global positioning system (GPS) sites scattered across the Western U.S.
Scientists Warn of Rising Oceans From Polar Melt, The New York Times. A large section of the mighty West Antarctica ice sheet has begun falling apart and its continued melting now appears to be unstoppable, two groups of scientists reported on May 12, 2014. If the findings hold up, they suggest that the melting could destabilize neighboring parts of the ice sheet and a rise in sea level of 10 feet (about 3 meters) or more may be unavoidable in coming centuries. Global warming caused by the human-driven release of greenhouse gases has helped to destabilize the ice sheet, though other factors may also be involved, the scientists said. The rise of the sea is likely to continue to be relatively slow for the rest of the twenty-first century, the scientists added, but in the more distant future it may accelerate markedly. The West Antarctic ice sheet sits in a bowl-shaped depression, with the base of the ice below sea level. Warm ocean water is causing the ice sitting along the rim of the bowl to thin and retreat. As the front edge of the ice pulls away from the rim and enters deeper water, it can retreat much faster than before. In a new paper published in Geophysical Research Letters, a team led by glaciologist Eric Rignot used satellite and airborne measurements to document an accelerating retreat of six glaciers draining into the Amundsen Sea region. With updated mapping of the terrain beneath the ice sheet, the team was able to rule out the presence of any mountains or hills significant enough to slow the retreat.
NASA Places Radar in North Carolina to Study Rain in Smokies, Washington Times. NASA placed two radars on land in Rutherford County, North Carolina, for a field campaign to study rainfall in the Great Smoky Mountains. The campaign ran from May 1 to June 15, 2014. “We have set up rain gauges and radars across the area to learn more about how weather and rain systems behave in the mountains,” said research scientist David Wolff. The campaign was designed to validate data from the Global Precipitation Measurement (GPM) mission’s Core Observatory, which launched in February 2014. The science team expected to end the six-week campaign with detailed data to improve their understanding of both the fundamental sciences of mountain rainfall and how best to estimate rainfall using satellite observations over remote and rugged regions. Scientists will use what they learn to improve weather predictions and flood warnings. Team members will take a break after the summer and are scheduled to travel to Seattle, Washington, in 2015-16 to measure winter weather there.
NASA ‘Balloon Campaign’ Goes to Australia, International Business Times. NASA and the University of Wyoming teamed up with the Australian Bureau of Meteorology (BOM) in Darwin, Australia, for a balloon-based campaign designed to better understand the composition and behavior of volcanic plumes. The Kelud Ash (KlAsh) experiment involved launching a series of balloons to take measurements of emissions from the volcano in Indonesia. Mt. Kelud sent small droplets of sulfuric acid—as ash particles and sulfate aerosol—up to 15 mi (25 km) above Earth when it erupted in February this year. Principal investigator Duncan Fairlie said: “The purpose is to better characterize particle sizes, composition, and optical properties from a relatively fresh volcanic plume in the stratosphere.” The two-week balloon campaign, which started on May 14, 2014, launched small balloon payloads over the Indian Ocean from the bushes of Darwin territory. Fairlie said the team sampled the volcanic plumes at an altitude of around 12 miles (20 kilometers) in all flights.