Global Warming

Global Warming

Global Warming

Global Warming

Global Warming

Global Warming

Global Warming

Global Warming

Global Warming

Global Warming

Wednesday, 7 December 2011

Satellite confirms decline in pollution from coal power plants

Adam Voiland and Rani Gran,
NASA's Goddard Space Flight Center

A team of scientists have used the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite to confirm major reductions in the levels of a key air pollutant generated by coal power plants in the eastern United States. The pollutant, sulfur dioxide, contributes to the formation of acid rain and can cause serious health problems.

The scientists, led by an Environment Canada researcher, have shown that sulfur dioxide levels in the vicinity of major coal power plants have fallen by nearly half since 2005. The new findings, the first satellite observations of this type, confirm ground-based measurements of declining sulfur dioxide levels and demonstrate that scientists can potentially measure levels of harmful emissions throughout the world, even in places where ground monitoring is not extensive or does not exist. About two-thirds of sulfur dioxide pollution in American air comes from coal power plants. Geophysical Research Letterspublished details of the new research this month.

These maps show average sulfur dioxide levels measured by the Aura satellite for the periods 2005-2007 (top) and 2008-2010 (bottom) over a portion of the eastern United States. The black dots represent the locations of many of the nation's top sulfur dioxide emissions sources. Larger dots indicate greater emissions. (Credit: NASA's Earth Observatory)

The scientists attribute the decline in sulfur dioxide to the Clean Air Interstate Rule, a rule passed by the U.S. Environmental Protection Agency in 2005 that called for deep cuts in sulfur dioxide emissions. In response to that rule, many power plants in the United States have installed desulfurization devices and taken other steps that limit the release of sulfur dioxide. The rule put a cap on emissions, but left it up to power companies to determine how to reduce emissions and allowed companies to trade pollution credits.

While scientists have used the Ozone Monitoring Instrument to observe sulfur dioxide levels within large plumes of volcanic ash and over heavily polluted parts of China in the past, this is the first time they have observed such subtle details over the United States, a region of the world that in comparison to fast-growing parts of Asia now has relatively modest sulfur dioxide emissions. Just a few decades ago, sulfur dioxide pollution was quite severe in the United States. Levels of the pollutant have dropped by about 75 percent since the 1980s due largely to the passage of the Clean Air Act.

Vitali Fioletov, a scientist based in Toronto at Environment Canada, and his colleagues developed a new mathematical approach that made the improved measurements a reality. The approach centers on averaging measurements within a 30 miles radius (50 km) of a sulfur dioxide source over several years. "Vitali has developed an extremely powerful technique that makes it possible to detect emissions even when levels of sulfur dioxide are about four times lower than what we could detect previously," said Nickolay Krotkov, a researcher based at NASA’s Goddard Space Flight Center in Greenbelt, Md., and a coauthor of the new paper.

The technique allowed Fioletov and his colleagues to pinpoint the sulfur dioxide signals from the 40 largest sulfur dioxide sources in the United States -- generally coal power plants that emit more than 70 kilotons of sulfur dioxide per year. The scientists observed major declines in sulfur dioxide emissions from power plants in Alabama, Georgia, Indiana, Kentucky, North Carolina, Ohio, Pennsylvania and West Virginia by comparing levels of the pollutant for an average of the period 2005 to 2007 with another average from 2008 to 2010.

What we’re seeing in these satellite observations represents a major environmental accomplishment," said Bryan Bloomer, an Environmental Protection Agency scientist familiar with the new satellite observations. "This is a huge success story for the EPA and the Clean Air Interstate Rule," he said.

The researchers focused their analysis on the United States to take advantage of the presence of a robust network of ground-based instruments that monitor sulfur dioxide emissions inside power plant smokestacks. The ground-based instruments have logged a 46 percent decline in sulfur dioxide levels since 2005 -- a finding consistent with the 40 percent reduction observed by OMI.

Smokestacks from a coal power plant in Maryland jut into a hazy skyline. Credit: Jeff Stehr, University of Maryland

"Now that we’ve confirmed that the technique works, the next step is to use it for other parts of the world that don’t have ground-based sensors," said Krotkov. "The real beauty of using satellites is that we can apply the same technique to the entire globe in a consistent way." In addition, the team plans to use a similar technique to monitor other important pollutants that coal power plants release, such as nitrogen dioxide, a precursor to ozone.
OMI, a Dutch and Finnish built instrument, was launched in 2004, as one of four instruments on the NASA Aura satellite, and can measure sulfur dioxide more accurately than any satellite instrument flown to date. Though OMI remains in very good condition and scientists expect it to continue producing high-quality data for many years, the researchers also hope to use data from an upcoming Dutch-built OMI follow-on instrument called TROPOMI that is expected to launch on a European Space Agency satellite in 2014.

Artist's concept of the Aura spacecraft. Credit: NASA

On July 6, 2011, the U.S. Environmental Protection Agency (EPA) finalized the Cross-State Air Pollution Rule (CSAPR), requiring 27 states to significantly reduce power plant emissions that contribute to ozone and fine particle pollution in other states. This rule replaces EPA's 2005 Clean Air Interstate Rule (CAIR). A December 2008 court decision kept the requirements of CAIR in place temporarily but directed EPA to issue a new rule to implement Clean Air Act requirements concerning the transport of air pollution across state boundaries. This action responds to the court's concerns.

Thanks NASA

Wednesday, 30 November 2011

NASA's Grace helps monitor U.S. drought

By Kelly Helm Smith,
National Drought Mitigation Center
Adam Voiland,
NASA's Earth Science News Team

New groundwater and soil moisture drought indicator maps produced by NASA are available on the National Drought Mitigation Center's website. They currently show unusually low groundwater storage levels in Texas. The maps use an 11-division scale, with blues showing wetter-than-normal conditions and a yellow-to-red spectrum showing drier-than-normal conditions. Image credit: NASA/National Drought Mitigation Center

The record-breaking drought in Texas that has fueled wildfires, decimated crops and forced cattle sales has also reduced groundwater levels in much of the state to the lowest levels in more than 60 years, according to new national maps produced by NASA using data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (Grace) mission. The map are distributed by the National Drought Mitigation Center at the University of Nebraska-Lincoln.

The latest groundwater map, released on Nov. 29, shows large patches of maroon over eastern Texas, indicating severely depressed groundwater levels. The maps, publicly available on the Drought Center's website at , are generated weekly by NASA's Goddard Space Flight Center in Greenbelt, Md., using Grace gravity field data calculated at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of Texas Center for Space Research, Austin.

"Texas groundwater will take months or longer to recharge," said Matt Rodell, a hydrologist based at Goddard. "Even if we have a major rainfall event, most of the water runs off. It takes a longer period of sustained greater-than-average precipitation to recharge aquifers significantly."

The twin Grace satellites, which JPL developed and manages for NASA, detect small changes in Earth's gravity field caused primarily by the redistribution of water on and beneath the land surface. The paired satellites travel about 137 miles (220 kilometers) apart and record small changes in the distance separating them as they encounter variations in Earth's gravitational field.

To make the maps, scientists use a sophisticated computer model that combines measurements of water storage from Grace with a long-term meteorological dataset to generate a continuous record of soil moisture and groundwater that stretches back to 1948. Grace data go back to 2002. The meteorological data include precipitation, temperature, solar radiation and other ground- and space-based measurements.

The color-coded maps show how much water is stored now as a probability of occurrence in the 63-year record. The maroon shading over eastern Texas, for example, shows that the level of dryness over the last week occurred less than two percent of the time between 1948 and the present.

The groundwater maps aren't the only maps based on Grace data that the Drought Center publishes each week. The Drought Center also distributes soil moisture maps that show moisture changes in the root zone down to about 3 feet (1 meter) below the surface, as well as surface soil moisture maps that show changes within the top inch (2 centimeters) of the land.

"All of these maps offer policymakers new information into subsurface water fluctuations at regional to national scales that has not been available in the past," said the Drought Center's Brian Wardlow. The maps provide finer resolution or are more consistently available than other similar sources of information, and having the maps for the three different levels should help decision makers distinguish between short-term and long-term droughts.

"These maps would be impossible to generate using only ground-based observations," said Rodell. "There are groundwater wells all around the United States, and the U.S. Geological Survey does keep records from some of those wells, but it's not spatially continuous and there are some big gaps."

The maps also offer farmers, ranchers, water resource managers and even individual homeowners a new tool to monitor the health of critical groundwater resources. "People rely on groundwater for irrigation, for domestic water supply, and for industrial uses, but there's little information available on regional to national scales on groundwater storage variability and how that has responded to a drought," Rodell said. "Over a long-term dry period, there will be an effect on groundwater storage and groundwater levels. It's going to drop quite a bit, people's wells could dry out, and it takes time to recover."

The maps are the result of a NASA-funded project at the Drought Center and NASA Goddard to make it easier for the weekly U.S. Drought Monitor to incorporate data from the Grace satellites. The groundwater and soil moisture maps are updated each Tuesday.

Tuesday, 29 November 2011

First light for NPP satellite

An image taken by the NPP Visible Infrared Imager Radiometer Suite (VIIRS) on Nov. 21, 2011. This high-resolution image is wrapped on a globe and shows a broad swath of Eastern North America from Canada’s Hudson Bay past Florida to the northern coast of Venezuela. The NASA NPP Team at the Space Science and Engineering Center, UW-Madison created the image using 3 channels (red, green and blue) of VIIRS data. Credit: NASA/NPP Team.

By Rani Gran,
NASA Goddard Space Flight Center

GREENBELT, Md. — The Visible Infrared Imager Radiometer Suite (VIIRS) onboard NASA's newest Earth-observing satellite, NPP, acquired its first measurements on Nov. 21, 2011. This high-resolution image is of a broad swath of Eastern North America from Canada’s Hudson Bay past Florida to the northern coast of Venezuela. The VIIRS data were processed at the NOAA Satellite Operations Facility in Suitland, Md.

VIIRS is one of five instruments onboard the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) satellite that launched from Vandenberg Air Force Base, Calif., on Oct. 28. Since then, NPP reached its final orbit at an altitude of 512 miles (824 kilometers), powered on all instruments and is traveling around the Earth at 16,640 miles an hour (eight kilometers per second).

"This image is a next step forward in the success of VIIRS and the NPP mission," said James Gleason, NPP project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md.

VIIRS will collect radiometric imagery in visible and infrared wavelengths of the Earth's land, atmosphere, and oceans. By far the largest instrument onboard NPP, VIIRS weighs about 556 pounds (252 kilograms). Its data, collected from 22 channels across the electromagnetic spectrum, will be used to observe the Earth's surface including fires, ice, ocean color, vegetation, clouds, and land and sea surface temperatures.

"VIIRS heralds a brightening future for continuing these essential measurements of our environment and climate," said Diane Wickland, NPP program scientist at NASA headquarters in Washington. She adds that all of NPP's five instruments will be up and running by mid-December and NPP will begin 2012 by sending down complete data.

A high-resolution version of the first VIIRS image created the NASA NPP Team at the Space Science and Engineering Center, UW-Madison. Credit: NASA/NPP Team.

"NPP is right on track to ring in the New Year," said Ken Schwer, NPP project manager at NASA Goddard. "Along with VIIRS, NPP carries four more instruments that monitor the environment on Earth and the planet's climate, providing crucial information on long-term patterns to assess climate change and data used by meteorologists to improve short-term weather forecasting."

NPP serves as a bridge mission from NASA's Earth Observing System (EOS) of satellites to the next-generation Joint Polar Satellite System (JPSS), a National Oceanic and Atmospheric Administration program that will also collect weather and climate data. During NPP's five-year life, the mission will extend more than 30 key long-term datasets that include measurements of the atmosphere, land and oceans. NASA has been tracking many of these properties for decades. NPP will continue measurements of land surface vegetation, sea surface temperature, and atmospheric ozone that began more than 25 years ago.

"The task now for the science community is to evaluate VIIRS performance and determine the accuracy of its data products," said Chris Justice a professor of geography at the University of Maryland, College Park, who will be using VIIRS data in his research.

"These long-term data records are critical in monitoring how the Earth's surface is changing — either from human activity or through climate change."

The end of the IceBridge

By Alan Brown,
NASA Dryden Flight Research Center

NASA's DC-8 airborne science laboratory has completed its 2011 Operation IceBridge science flights over Antarctica, and arrived home at its base in Palmdale, Calif., Nov. 22. The IceBridge flight and science team flew a record 24 science flights during the six-week campaign, recording data from a suite of sophisticated instruments on the thickness and depth of Antarctic ice sheets and glacial movement.

The aircraft departed its deployment base at Punta Arenas, Chile, Tuesday morning Nov. 22 and after a refueling stop in Santiago, Chile, set course for Los Angeles International Airport for customs clearance. The flying lab continued on to the Dryden Aircraft Operations Facility in Palmdale, arriving about 8:30 p.m. that evening after almost 15 hours in the air.

A highlight of the IceBridge mission was the discovery during a low-level overflight Oct. 14 of a large crack that had recently begun across the Pine Island Glacier ice shelf, a precursor to the separation of an estimated 310-square-mile iceberg into the ocean in the near future. The growth of the estimated 18-mile-long rift was documented on several subsequent flights.

This is a pilot's eye view of the display from the Airborne Topographic Mapper developed by NASA's Wallops Flight Facility that allowed the DC-8 pilots to fly the exact route flown previously in earlier IceBridge missions, assuring that data collected can be compared to the previous years. Credit: NASA/Dick Ewers

The final science flights on Nov. 17 and 19 focused on the middle of the Antarctic Peninsula and the George VI Sound on the peninsula's western side.
Mission manager Chris Miller's report on the former noted that clear weather over the eastern side of the peninsula provided "a rare opportunity to collect data over glaciers that are more regularly shrouded in cloud." The mostly clear weather allowed the science team to collect data at low altitudes of only 1,500 feet above ground for almost seven hours out of the more than 11 hours the team was aloft.

After a down day on Nov. 18 for crew rest and aircraft maintenance, the converted four-engine jetliner-turned-flying-laboratory was airborne again on its final science mission of the 2011 Antarctic IceBridge campaign Nov. 19. The IceBridge team found perfect weather conditions over their survey target, the George VI Sound on the western side of the Antarctic Peninsula.

Data collection began with a long transect down the center of the sound, Miller reported, and then continued with 11 flight data lines stitching across the sound, shore to shore. Minor glitches with the Digital Mapping System and the aircraft's GPS system complicated one of the flight tracks for the Airborne Topographic Mapper instrument during the flight, but Miller said all objectives were met and the ATM data should be recoverable in post flight processing.

"Views of mountain peaks and ranges were abundant," during the 11-hour flight, he added.

The frozen, inhospitable surface features of Alexander Island in Antarctica were viewed at close range during one of the final low-level flights by NASA's DC-8 flying laboratory during the 2011 Operation IceBridge mission. Credit: NASA/Chris Miller

Due to fuel supply issues at Punta Arenas, a 25th and final science flight on Nov. 20 was cancelled, and the team prepared for its Nov. 22 departure back to the United States.

Including the transit flights between Punta Arenas and California, the modified 45-year-old flying laboratory logged about 308 flight hours during the Operation IceBridge, including 127 hours of actual data collection from its suite of seven specialized instruments. The instruments and science teams represented several NASA centers, the University of Kansas, the University of California at Santa Cruz and the Lamont-Doherty Earth Observatory at Columbia University.

Operation IceBridge was begun in 2009 to bridge the gap in data collection after NASA's ICESat-1 satellite stopped functioning and when the ICESat-2 satellite becomes operational in 2016. By comparing the year-to-year readings of ice thickness and movement both on land and on the sea, scientists can learn more about the trends that could affect sea-level rise and climate around the globe. In addition to NASA's DC-8, a smaller Gulfstream V aircraft operated by the National Science Foundation and the National Center for Atmospheric Research also participated in this fall's IceBridge mission.

DC-8 research pilot Troy Asher, who flew the final science flight, offered his reflections on this fall's Antarctic campaign.
"As you will undoubtedly hear from other reports from the science and mission director community, this has been a fantastic deployment from many different aspects," he said.

NASA's Dryden Flight Research Center director David McBride emailed his congratulations to the science team and the flight and ground crews on the completion of the 2011 mission over Antarctica.

"This was a great campaign and it makes all proud," McBride added.

Thursday, 10 November 2011

To the ends of the Earth

A close-up image of the crack spreading across the ice shelf of Pine Island Glacier shows the details of the boulder-like blocks of ice that fell into the rift when it split. For most of the 18-mile stretch of the crack that NASA’s DC-8 flew over on Oct. 26, 2011, it stretched about 240 feet wide, as roughly seen here. The deepest points ranged from about 165 to 190 feet, roughly equal to the top of the ice shelf down to sea level. Scientists expect the crack to propagate and the ice shelf to calve an iceberg of more than 300 square miles in the coming months. This image was captured by the Digital Mapping System (DMS) aboard the DC-8. Credit: NASA/DMS.

UPDATE: In further research, it has come to our attention that Pine Island Glacier last calved a large iceberg in 2007.

PUNTA ARENAS, CHILE — NASA's airborne expedition over Antarctica this October and November has measured the change in glaciers vital to sea level rise projections and mapped others rarely traversed by humans.

Operation IceBridge, nearing completion of its third year, is the largest airborne campaign ever flown over the world's polar regions. Bridging a gap between two ice elevation mapping satellites, and breaking new scientific ground on its own, IceBridge has charted the continued rapid acceleration and mass loss of Pine Island Glacier this fall.

IceBridge has now generated three years of laser altimetry data over certain locations to continue the record from NASA's Ice Climate and Elevation Satellite (ICESat), which stopped operating in 2009. IceBridge measurements show Pine Island following its rapid deterioration that began around 2006. Combined IceBridge and ICESat data show the glacier is losing more than six times as much mass per year — mass loss was measured at 7 gigatons a year in 2005 and about 46 gigatons a year in 2010 — making it one of the most significant climate change response trends that scientists see worldwide. For comparison, the Chesapeake Bay holds about 70 gigatons of water.

Satellites still operating, such as NASA's Gravity Recovery and Climate Experiment (GRACE), can provide a large-scale picture of this trend. But it takes a more focused mission such as Operation IceBridge to gather higher-resolution data near the surface to piece together the dynamic interactions of ice, bedrock and ocean currents behind specific changes, and to improve the models that scientists use to predict how much an unstable ice sheet like West Antarctica will contribute to sea level rise.

Two planes make up this year's Antarctica 2011 campaign — NASA's DC-8 flying laboratory, based at Dryden Flight Research Center, Palmdale, Cal., and a Gulfstream-V owned by the National Science Foundation and operated by the National Center for Atmospheric Research. The campaign also spotted and flew over a large rift developing across the Pine Island ice shelf on Oct. 14. A natural process, the crack could calve a new iceberg of about 350 square miles of surface area in the coming weeks or months. Pine Island Glacier hasn't calved a major iceberg since 2001.

The National Science Foundations/National Center for Atmospheric Research (NSF/NCAR) Gulfstream-V flew high-attitude missions during IceBridge Antarctica 2011. Credit: NCAR.

On a follow-up flight on Oct. 26 to gather data around Pine Island's grounding line, the DC-8 was able to fly along the crack for about 18 miles at an altitude of 3,000 feet, making what are believed to be the first detailed airborne measurements of an active calving rift.

In flights to Slessor and Recovery glaciers, which have only been traversed by humans once and twice respectively, IceBridge made a historic and scientifically important suite of measurements. Perhaps most significantly for these rarely studied regions of East Antarctica, an ice-penetrating radar instrument onboard the DC-8 was able to measure the topography of the bedrock underneath the ice sheet. Without a better understanding of the shape and contour of the bedrock, it is impossible to know how much ice sits on top of the continent in all. Topography also greatly influences the speed and direction of a glacier's ice flow.

NASA's DC-8 handled the low-attitude missions and carried the bulk of the IceBridge science instruments. Credit: NASA/Tony Landis.

"At a time when glaciers and ice sheets are showing rapid changes, we need consistent data that shows how and why that change is happening," IceBridge project scientist Michael Studinger said. "With three years of IceBridge data in hand, we have successfully continued the ice sheet elevation record in key areas and broken new ground in understanding the nature of the bedrock under ice sheets and the shape of the seafloor under ice shelves."

A gravimeter aboard the DC-8 senses changes in gravity fields to map the sea floor. This bathymetry controls ocean currents, which can inject warming waters under ice shelves and accelerate their thinning, as is happening at Pine Island and other glaciers.

The G-V was outfitted with one instrument for this campaign — a laser-ranging topographic mapper called the Land, Vegetation and Ice Sensor (LVIS). The instrument is suited for measuring large swaths of the surface at high altitudes. The G-V flew at around 45,000 feet for most of its 2011 missions.

Meanwhile, the DC-8 carries multiple instruments which are better suited for low-altitude flying. Once the plane reaches its science target, it flies at about 1,500 feet, allowing the radars, gravimeter, digital cameras and the Airborne Topographic Mapper (ATM), which captures higher resolution details of the ice surface than is possible from satellites. The DC-8's range and speed can also reach more remote, unstudied locations and cover more ground than smaller aircraft or ground traverses.

"This has been an excellent campaign for the science side of the mission, and it's our job to put the plane in positions to make that possible," said Mission Manager Walter Klein, based at Dryden.

One example of the flight side of the mission enabling science occurred during the second Pine Island Glacier flight, when the pilots flew the DC-8 by sight over the calving rift in the glacier's ice shelf at an altitude of 3,000 feet.

During the IceBridge Antarctica 2011 campaign, the DC-8 has flown 13 missions covering 51,600 miles, while the G-V has flown 11 science missions covering about 50,000 miles. As planned, the G-V left Punta Arenas to return to the United States on Weds., Nov. 2. The DC-8 is scheduled to remain in Punt Arenas up to mid-November, when it will return to its home base of Dryden Flight Research Center in Palmdale, Cal.

The next flight leg of IceBridge once the mission team wraps up in Punta Arenas will be based in Greenland in the Northern Hemisphere spring of 2012. IceBridge is scheduled to fly one Arctic and one Antarctic leg each year until ICESat-2 launches in 2016.

More . . .

Friday, 4 November 2011

Watching the birth of an iceberg

A photo from the window of NASA's DC-8 shows the rift across the Pine Island Glacier ice shelf running off toward the horizon.Credit: Michael Studinger/NASA

PUNTA ARENAS, CHILE – After discovering an emerging crack that cuts across the floating ice shelf of Pine Island Glacier in Antarctica, NASA's Operation IceBridge has flown a follow-up mission and made the first-ever detailed airborne measurements of a major iceberg calving in progress.

NASA's Operation Ice Bridge, the largest airborne survey of Earth's polar ice ever flown, is in the midst of its third field campaign from Punta Arenas, Chile. The six-year mission will yield an unprecedented three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice.

Pine Island Glacier last calved a significant iceberg in 2001, and some scientists have speculated recently that it was primed to calve again. But until an Oct. 14 IceBridge flight of NASA's DC-8, no one had seen any evidence of the ice shelf beginning to break apart. Since then, a more detailed look back at satellite imagery seems to show the first signs of the crack in early October.

While Pine Island has scientists' attention because it is both big and unstable – scientists call it the largest source of uncertainty in global sea level rise projections – the calving underway now is part of a natural process for a glacier that terminates in open water. Gravity pulls the ice in the glacier westward along Antarctica's Hudson Mountains toward the Amundsen Sea. A floating tongue of ice reaches out 30 miles into the Amundsen beyond the grounding line, the below-sea-level point where the ice shelf locks onto the continental bedrock. As ice pushes toward the sea from the interior, inevitably the ice shelf will crack and send a large iceberg free.

"We are actually now witnessing how it happens and it’s very exciting for us," said IceBridge project scientist Michael Studinger, Goddard Space Flight Center, Greenbelt, Md. "It’s part of a natural process but it’s pretty exciting to be here and actually observe it while it happens. To my knowledge, no one has flown a lidar instrument over an actively developing rift such as this."

A primary goal of Operation IceBridge is to put the same instruments over the exact same flight lines and satellite tracks, year after year, to gather meaningful and accurate data of how ice sheets and glaciers are changing over time. But discovering a developing rift in one of the most significant science targets in the world of glaciology offered a brief change in agenda for the Oct. 26 flight, if only for a 30-minute diversion from the day's prescribed flight lines.

The IceBridge team observed the rift running across the ice shelf for about 18 miles. The lidar instrument on the DC-8, the Airborne Topographic Mapper, measured the rift's shoulders about 820 feet apart (250 meters) at its widest, although the rift stretched about 260 feet wide along most of the crack. The deepest points from the ice shelf surface ranged 165 to 195 feet (50 to 60 meters). When the iceberg breaks free it will cover about 340 square miles (880 square kilometers) of surface area. Radar measurements suggested the ice shelf in the region of the rift is about 1,640 feet (500 meters) feet thick, with only about 160 feet of that floating above water and the rest submerged. It is likely that once the iceberg floats away, the leading edge of the ice shelf will have receded farther than at any time since its location was first recorded in the 1940s.

In October, 2011, NASA's Operation IceBridge discovered a major rift in the Pine Island Glacier in western Antarctica. This crack, which extends at least 18 miles and is 50 meters deep, could produce an iceberg more than 800 square kilometers in size. IceBridge scientists returned soon after to make the first-ever detailed airborne measurements of a major iceberg calving in progress. Credit: NASA/Goddard/Jefferson Beck

Veteran DC-8 pilot Bill Brockett first flew the day's designed mission, crisscrossing the flow of the glacier near the grounding line to gather data on its elevation, topography and thickness. When it came time to investigate the crack, Brockett flew across it before turning to fly along the rift by sight. The ATM makes its precision topography maps with a laser than scans 360 degrees 20 times per second, while firing 3,000 laser pulses per second. When flying at an altitude of 3,000 feet, as during this flight, it measures a swath of the surface about 1,500 feet wide. As the crack measured at more than 800 feet wide in places, it was important for Brockett to hold tight over the crevasse.

"The pilots did a really nice job of keeping the aircraft and our ATM scan swath pretty much centered over the rift as you flew from one end to the other," said Jim Yungel, who leads the ATM team out of NASA's Wallops Island Flight Facility in Virginia. "It was a real challenge to be told…we’re going to attempt to fly along it and let’s see if your lidar systems can map that crack and can map the bottom of the crack.

"And it was a lot of fun on a personal level to see if something that you built over the years can actually do a job like that. So, yeah, I enjoyed it. I really enjoyed seeing the results being produced."

While the ATM provided the most detailed measurements of the topography of the rift, other instruments onboard the DC-8 also captured unique aspects. The Digital Mapping System, a nadir-view camera, gathered high-definition close-ups of the craggy split. On the flight perpendicular to the crack, the McCORDS radar also measured its depth and the thickness of the ice shelf in that region.

Catching the rift in action required a bit of luck, but is also testimony to the science benefit of consistent, repeated trips and the flexibility of a manned mission in the field.

"A lot of times when you’re in science, you don’t get a chance to catch the big stories as they happen because you’re not there at the right place at the right time," said John Sonntag, Instrument Team Lead for Operation IceBridge, based at Goddard Space Flight Center. "But this time we were."

Tuesday, 4 October 2011

NASA Leads Study of Unprecedented Arctic Ozone Loss

October 02, 2011

PASADENA, Calif. - A NASA-led study has documented an unprecedented depletion of Earth's protective ozone layer above the Arctic last winter and spring caused by an unusually prolonged period of extremely low temperatures in the stratosphere.

The study, published online Sunday, Oct. 2, in the journal Nature, finds the amount of ozone destroyed in the Arctic in 2011 was comparable to that seen in some years in the Antarctic, where an ozone "hole" has formed each spring since the mid-1980s. The stratospheric ozone layer, extending from about 10 to 20 miles (15 to 35 kilometers) above the surface, protects life on Earth from the sun's harmful ultraviolet rays.

The Antarctic ozone hole forms when extremely cold conditions, common in the winter Antarctic stratosphere, trigger reactions that convert atmospheric chlorine from human-produced chemicals into forms that destroy ozone. The same ozone-loss processes occur each winter in the Arctic. However, the generally warmer stratospheric conditions there limit the area affected and the time frame during which the chemical reactions occur, resulting in far less ozone loss in most years in the Arctic than in the Antarctic.

To investigate the 2011 Arctic ozone loss, scientists from 19 institutions in nine countries (United States, Germany, The Netherlands, Canada, Russia, Finland, Denmark, Japan and Spain) analyzed a comprehensive set of measurements. These included daily global observations of trace gases and clouds from NASA's Aura and CALIPSO spacecraft; ozone measured by instrumented balloons; meteorological data and atmospheric models. The scientists found that at some altitudes, the cold period in the Arctic lasted more than 30 days longer in 2011 than in any previously studied Arctic winter, leading to the unprecedented ozone loss. Further studies are needed to determine what factors caused the cold period to last so long.

"Day-to-day temperatures in the 2010-11 Arctic winter did not reach lower values than in previous cold Arctic winters," said lead author Gloria Manney of NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the New Mexico Institute of Mining and Technology in Socorro. "The difference from previous winters is that temperatures were low enough to produce ozone-destroying forms of chlorine for a much longer time. This implies that if winter Arctic stratospheric temperatures drop just slightly in the future, for example as a result of climate change, then severe Arctic ozone loss may occur more frequently."

The 2011 Arctic ozone loss occurred over an area considerably smaller than that of the Antarctic ozone holes. This is because the Arctic polar vortex, a persistent large-scale cyclone within which the ozone loss takes place, was about 40 percent smaller than a typical Antarctic vortex. While smaller and shorter-lived than its Antarctic counterpart, the Arctic polar vortex is more mobile, often moving over densely populated northern regions. Decreases in overhead ozone lead to increases in surface ultraviolet radiation, which are known to have adverse effects on humans and other life forms.

Although the total amount of Arctic ozone measured was much more than twice that typically seen in an Antarctic spring, the amount destroyed was comparable to that in some previous Antarctic ozone holes. This is because ozone levels at the beginning of Arctic winter are typically much greater than those at the beginning of Antarctic winter.

Manney said that without the 1989 Montreal Protocol, an international treaty limiting production of ozone-depleting substances, chlorine levels already would be so high that an Arctic ozone hole would form every spring. The long atmospheric lifetimes of ozone-depleting chemicals already in the atmosphere mean that Antarctic ozone holes, and the possibility of future severe Arctic ozone loss, will continue for decades.

"Our ability to quantify polar ozone loss and associated processes will be reduced in the future when NASA's Aura and CALIPSO spacecraft, whose trace gas and cloud measurements were central to this study, reach the end of their operational lifetimes," Manney said. "It is imperative that this capability be maintained if we are to reliably predict future ozone loss in a changing climate."

Other institutions participating in the study included Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany; NASA Langley Research Center, Hampton, Va.; Royal Netherlands Meteorological Institute, De Bilt, The Netherlands; Delft University of Technology, 2600 GA Delft, The Netherlands; Science Systems and Applications, Inc., Greenbelt, Md., and Hampton, Va.; Science and Technology Corporation, Lanham, Md.; Environment Canada, Toronto, Ontario, Canada; Central Aerological Observatory, Russia; NOAA Earth System Research Laboratory, Boulder, Colo.; Arctic Research Center, Finnish Meteorological Institute, Finland; Danish Climate Center, Danish Meteorological Institute, Denmark; Eindhoven University of Technology, Eindhoven, The Netherlands; Arctic and Antarctic Research Institute, St. Petersburg, Russia; National Institute for Environmental Studies, Japan; National Institute for Aerospace Technology, Spain; and University of Toronto, Ontario, Canada.

For more information on NASA's Aura mission, visit: . For more information on NASA's CALIPSO mission, visit: .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

More . . .

Thursday, 18 August 2011

First complete map of Antarctica ice flow

[ First complete map of the speed and direction of ice flow in Antarctica, derived from radar interferometric data. Image credit: NASA/JPL-Caltech/UCI ]


By Alan Buis
NASA Jet Propulsion Laboratory

PASADENA, Calif. - NASA-funded researchers have created the first complete map of the speed and direction of ice flow in Antarctica. The map, which shows glaciers flowing thousands of miles from the continent's deep interior to its coast, will be critical for tracking future sea-level increases from climate change. The team created the map using integrated radar observations from a consortium of international satellites.

"This is like seeing a map of all the oceans' currents for the first time. It's a game changer for glaciology," said Eric Rignot of NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the University of California (UC), Irvine. Rignot is lead author of a paper about the ice flow published online Thursday in Science Express. "We are seeing amazing flows from the heart of the continent that had never been described before."

Rignot and UC Irvine scientists Jeremie Mouginot and Bernd Scheuchl used billions of data points captured by European, Japanese and Canadian satellites to weed out cloud cover, solar glare and land features masking the glaciers. With the aid of NASA technology, the team painstakingly pieced together the shape and velocity of glacial formations, including the previously uncharted East Antarctica, which comprises 77 percent of the continent.

Like viewers of a completed jigsaw puzzle, the scientists were surprised when they stood back and took in the full picture. They discovered a new ridge splitting the 5.4 million-square-mile (14 million-square-kilometer) landmass from east to west.

The team also found unnamed formations moving up to 800 feet (244 meters) annually across immense plains sloping toward the Antarctic Ocean and in a different manner than past models of ice migration.

"The map points out something fundamentally new: that ice moves by slipping along the ground it rests on," said Thomas Wagner, NASA's cryospheric program scientist in Washington. "That's critical knowledge for predicting future sea level rise. It means that if we lose ice at the coasts from the warming ocean, we open the tap to massive amounts of ice in the interior."

The work was conducted in conjunction with the International Polar Year (IPY) (2007-2008). Collaborators worked under the IPY Space Task Group, which included NASA; the European Space Agency (ESA); Canadian Space Agency (CSA); Japan Aerospace Exploration Agency; the Alaska Satellite Facility in Fairbanks; and MacDonald, Dettwiler and Associates of Richmond, British Columbia, Canada. The map builds on partial charts of Antarctic ice flow created by NASA, CSA and ESA using different techniques.

"To our knowledge, this is the first time that a tightly knit collaboration of civilian space agencies has worked together to create such a huge dataset of this type," said Yves Crevier of CSA. "It is a dataset of lasting scientific value in assessing the extent and rate of change in polar regions."

More . . .

Monday, 15 August 2011

Tohoku tsunami created icebergs in Antarctica

Before (left) and after (right) photos of the Sulzberger Ice Shelf illustrate the calving event associated with the Japan earthquake and resulting tsunami that occurred on March 11, 2011. The icebergs have just begun to separate in the left image. Credit: European Space Agency/Envisat

By Patrick Lynch, NASA Goddard Space Flight Center
Steve Koppes, University of Chicago

A NASA scientist and her colleagues were able to observe for the first time the power of an earthquake and tsunami to break off large icebergs a hemisphere away.

Kelly Brunt, a cryosphere specialist at Goddard Space Flight Center, Greenbelt, Md., and colleagues were able to link the calving of icebergs from the Sulzberger Ice Shelf in Antarctica following the Tohoku Tsunami, which originated with an earthquake off the coast of Japan in March 2011. The finding, detailed in a paper published online today in the Journal of Glaciology, marks the first direct observation of such a connection between tsunamis and icebergs.

The birth of an iceberg can come about in any number of ways. Often, scientists will see the towering, frozen monoliths break into the polar seas and work backwards to figure out the cause.

So when the Tohoku Tsunami was triggered in the Pacific Ocean on March 11 this spring, Brunt and colleagues immediately looked south. All the way south. Using multiple satellite images, Brunt, Emile Okal at Northwestern University and Douglas MacAyeal at University of Chicago were able to observe new icebergs floating off to sea shortly after the sea swell of the tsunami reached Antarctica.

To put the dynamics of this event in perspective: An earthquake off the coast of Japan caused massive waves to explode out from its epicenter. Swells of water swarmed toward an ice shelf in Antarctica, 8,000 miles (13,600 km) away, and about 18 hours after the earthquake occurred, those waves broke off several chunks of ice that together equaled about two times the surface area of Manhattan. According to historical records, this particular piece of ice hadn't budged in at least 46 years before the tsunami came along.

And as all that was happening, scientists were able to watch the Antarctic ice shelves in as close to real-time as satellite imagery allows, and catch a glimpse of a new iceberg floating off into the Ross Sea.

"In the past we've had calving events where we've looked for the source. It's a reverse scenario – we see a calving and we go looking for a source," Brunt said. "We knew right away this was one of the biggest events in recent history – we knew there would be enough swell. And this time we had a source."

Scientists first speculated in the 1970s that repeated flexing of an ice shelf – a floating extension of a glacier or ice sheet that sits on land – by waves could cause icebergs to break off. Scientific papers in more recent years have used models and tide gauge measurements in an attempt to quantify the impact of sea swell on ice shelf fronts.

The swell was likely only about a foot high (30 cm) when it reached the Sulzberger shelf. But the consistency of the waves created enough stress to cause the calving. This particular stretch of floating ice shelf is about 260 feet (80 meters) thick, from its exposed surface to its submerged base.

When the earthquake happened, Okal immediately honed in on the vulnerable faces of the Antarctic continent. Using knowledge of iceberg calving and what a NOAA model showed of the tsunami's projected path across the unobstructed Pacific and Southern oceans, Okal, Brunt and MacAyeal began looking at what is called the Sulzberger Ice Shelf. The Sulzberger shelf faces Sulzberger Bay and New Zealand.

Through a fortuitous break in heavy cloud cover, Brunt spotted what appeared to be a new iceberg in MODerate Imaging Spectroradiometer (MODIS) data.

[Nearly 50 square miles of ice broke off the Sulzberger Ice Shelf on the coast of Antarctica, resulting from waves generated by the Tohoku earthquake and tsunami that struck Japan in March 2011]

"I didn't have strong expectations either way whether we'd be able to see something," Brunt said. "The fastest imagery I could get to was from MODIS Rapid Response, but it was pretty cloudy. So I was more pessimistic that it would be too cloudy and we couldn't see anything. Then, there was literally one image where the clouds cleared, and you could see a calving event."

A closer look with synthetic aperture radar data from the European Space Agency satellite, Envisat, which can penetrate clouds, found images of two moderate-sized icebergs – with more, smaller bergs in their wake. The largest iceberg was about four by six miles in surface area – itself about equal to the surface area of one Manhattan. All the ice surface together about equaled two Manhattans. After looking at historical satellite imagery, the group determined the small outcropping of ice had been there since at least 1965, when it was captured by USGS aerial photography.

[Thick cloud cover briefly fell away to reveal this first image of icebergs breaking away from the Sulzberger Ice Shelf due to sea swell from the Tohoku Tsunami, which had originated 8,000 miles away about 18 hours earlier. The icebergs can be seen behind a thin layer of clouds just off the ice shelf near the center of the image. Source: MODIS Rapid Response/NASA.]

The proof that seismic activity can cause Antarctic iceberg calving might shed some light on our knowledge of past events, Okal said.

"In September 1868, Chilean naval officers reported an unseasonal presence of large icebergs in the southernmost Pacific Ocean, and it was later speculated that they may have calved during the great Arica earthquake and tsunami a month earlier," Okal said. "We know now that this is a most probable scenario."

MacAyeal said the event is more proof of the interconnectedness of Earth systems.

"This is an example not only of the way in which events are connected across great ranges of oceanic distance, but also how events in one kind of Earth system, i.e., the plate tectonic system, can connect with another kind of seemingly unrelated event: the calving of icebergs from Antarctica's ice sheet," MacAyeal said.

In what could be one of the more lasting observations from this whole event, the bay in front of the Sulzberger shelf was largely lacking sea ice at the time of the tsunami. Sea ice is thought to help dampen swells that might cause this kind of calving. At the time of the Sumatra tsunami in 2004, the potentially vulnerable Antarctic fronts were buffered by a lot of sea ice, Brunt said, and scientists observed no calving events that they could tie to that tsunami.

"There are theories that sea ice can protect from calving. There was no sea ice in this case," Brunt said. "It’s a big chunk of ice that calved because of an earthquake 13,000 kilometers away. I think it's pretty cool."

And as all that was happening, scientists were able to watch the Antarctic ice shelves in as close to real-time as satellite imagery allows, and catch a glimpse of a new iceberg floating off into the Ross Sea.

More . . . 

Tuesday, 2 August 2011

Researchers document ice loss after Antarctic shelf collapse

[The Larsen B ice shelf began disintegrating around Jan. 31, 2002. Its eventual collapse into the Weddell Sea remains the largest in a series of Larsen ice shelf losses in recent decades, and a team of international scientists has now documented the continued glacier ice loss in the years following the dramatic event. NASA’s MODerate Imaging Spectroradiometer (MODIS) captured this image on Feb. 17, 2002. (Credit: MODIS, NASA's Earth Observatory)]


An international team of researchers has combined data from multiple sources to provide the clearest account yet of how much glacial ice surges into the sea following the collapse of Antarctic ice shelves.

The work by researchers at the University of Maryland, Baltimore County (UMBC), the Laboratoire d'Etudes en Géophysique et Océanographie Spatiales, Centre National de la Recherche Scientifique at the University of Toulouse, France, and the University of Colorado's National Snow and Ice Data Center, Boulder, Colo., details recent ice losses while promising to sharpen future predictions of further ice loss and sea level rise likely to result from ongoing changes along the Antarctic Peninsula.

"Not only do you get an initial loss of glacial ice when adjacent ice shelves collapse, but you get continued ice losses for many years – even decades – to come," says Christopher Shuman, a researcher at UMBC's Joint Center for Earth Systems Technology (JCET) at NASA's Goddard Space Flight Center, Greenbelt, Md. Shuman is lead author of the study published online July 25 in the Journal of Glaciology. "This further demonstrates how important ice shelves are to Antarctic glaciers."

An ice shelf is a thick floating tongue of ice, fed by a tributary glacier, extending into the sea off a land mass. Previous research showed that the recent collapse of several ice shelves in Antarctica led to acceleration of the glaciers that feed into them. Combining satellite data from NASA and the French space agency CNES, along with measurements collected during aircraft missions similar to ongoing NASA IceBridge flights, Shuman, Etienne Berthier, of the University of Toulouse, and Ted Scambos, of the University of Colorado, produced detailed ice loss maps from 2001 to 2009 for the main tributary glaciers of the Larsen A and B ice shelves, which collapsed in 1995 and 2002, respectively.

[The Landsat Image Mosaic of Antarctica (LIMA) provides this “flyover” view of the Larsen Ice Shelf’s long reach out into the Weddell Sea. (Credit: LIMA)]

"The approach we took drew on the strengths of each data source to produce the most complete picture yet of how these glaciers are changing," Berthier said, noting that the study relied on easy access to remote sensing information provided by NASA and CNES. The team used data from NASA sources including the MODerate Imaging Spectroradiometer (MODIS) instruments and the Ice, Cloud and land Elevation Satellite (ICESat).

The analysis reveals rapid elevation decreases of more than 500 feet for some glaciers, and it puts the total ice loss from 2001 to 2006 squarely between the widely varying and less certain estimates produced using an approach that relies on assumptions about a glacier's mass budget.

The authors' analysis shows ice loss in the study area of at least 11.2 gigatons (11.2 billion tons) per year from 2001 to 2006. Their ongoing work shows ice loss from 2006 to 2010 was almost as large, averaging 10.2 gigatons (10.2 billion tons) per year.

More . . .

Wednesday, 1 June 2011

Cold front, warm front

[acquired November 26, 2011]

Weather fronts are as familiar as rain. For those who live outside of Earth’s tropics, the movement of warm and cold masses of air creates the weather, and when the two clash, it often rains. Understanding what happens when cold and warm air meet (cold and warm fronts) has given meteorologists the ability to predict the weather.

But for all of their familiarity with fronts, scientists have only recently gotten a detailed view of them. These four images contrast computer models of weather fronts (lower images) with the view from NASA’s Cloudsat (top), a space-based radar. The radar instrument on the satellite provides a detailed view of the cloud structure and precipitation in the clouds, helping scientists refine their understanding of common weather patterns and improve their ability to predict the weather.

The left image pair shows a cold front moving from left to right into a warm mass of air. The cold, dense air lifts the warm air like a wedge. The rising, warm air forms distinctive anvil-shaped clouds, visible in both the satellite and model image. Along the leading edge of the front, the rising air can develop into intense thunderstorms with heavy bursts of rain if there is enough moisture in the air.

Rain droplets send a stronger radar signal back to the satellite. This means that areas of heavy rain are dark blue, while lighter rain is lighter in color. The Cloudsat image shows a single area of concentrated rain surrounded by a line of lighter rain. The less detailed model shows a broad swath of rain. Cloudsat also reveals a line of low, rain-producing clouds behind the front that the model missed.

The right image pair shows a warm front moving from left to right over a cold mass of air. In this case, the lighter, warmer air lifts gradually over the cold air. The rising air cools and condenses into a wide area of clouds and steady rain. While both the satellite and the model detect the rain (shown in dark blue), Cloudsat shows more rain over a wider area.

Cloudsat launched on April 28, 2006, and began to take measurements a little over a month later. The moment the satellite turned on, its first image showed the structure of both a cold front and a warm front in detail scientists had never seen before. In the five years since, the instrument has provided numerous observations of cloud structures, from the unusual—hurricanes—to the mundane, common fronts.

More . ..

Tuesday, 3 May 2011

Two NASA Sites Win Webby Awards

WASHINGTON -- Two NASA websites have been recognized in the 15th Annual Webby Awards -- the leading international honor for the world's best Internet sites.

NASA's main website,, received its third consecutive People's Voice Award for best government site. NASA's Global Climate Change site at, which won last year's People's Voice Award for science, won the 2011 judges' award for best science site.

"NASA is committed to sharing its compelling story with people everywhere and with every communication tool," said David Weaver, NASA's associate administrator for communications. "We are very grateful to the online community for its continued support of what we are doing, and are excited about our future."

NASA recently posted new interactive pieces on the 30th anniversary of the Space Shuttle Program and the 50th anniversary of the first U.S. spaceflight. And in the last year, the agency has streamlined its online video presentation into a single player and deployed a version of the site optimized for mobile devices.

"NASA has a very broad-based Web team that can take content, literally the best raw material in the universe, and create compelling imagery, video and multimedia pieces to tell the agency's story," said Internet Services Manager Brian Dunbar in the Office of Communications at NASA Headquarters in Washington.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Global Climate Change site for the agency's Science Mission Directorate.

"NASA satellites take key measurements of our climate, and the Global Climate Change site gives the public access to that data as a visual, immersive experience," said Randal Jackson, JPL's Internet communications manager for the Global Climate Change site. "We're grateful for the high degree of interest the public has shown in Earth's vital signs."

NASA has had a Web presence almost since HTML was invented in the early 1990's, but the site's popularity skyrocketed after a 2003 redesign and relaunch focused on making it more usable and understandable for the general public. Since then, there have been more than 1.5 billion visits to the site, and its customer-satisfaction ratings are among the highest in government and comparable to popular commercial sites.

Reaching beyond the agency's website, NASA's online communications include a Facebook page with more than 368,000 "likes"; a Twitter feed with more than a million followers; and more than 160 accounts across a variety of social media platforms. Last fall, NASA placed first by a wide margin in the L2 Digital IQ Index for the Public Sector study that ranks 100 public sector organizations in the effectiveness of their websites, digital outreach, social media use and mobile sites.

The Office of Communications and the Office of the Chief Information Officer, both at NASA Headquarters, manage the agency's website.

Presented by the International Academy of Digital Arts and Sciences, the Webby Award recognizes excellence in technology and creativity. The academy created the awards in 1996 to help drive the creative, technical, and professional progress of the Internet and evolving forms of interactive media. While members of the International Academy of Digital Arts and Sciences select the Webby award winners, the online community determines the winners of the People's Voice Awards.

To find all the ways you can connect and collaborate with NASA, visit:

The California Institute of Technology in Pasadena manages JPL for NASA.

More . . .

Tuesday, 5 April 2011

Benefits of cleaner vehicles


By Adam Voiland
NASA's Earth Science News Team

A new analysis, published this week and conducted by a team of scientists led by Drew Shindell of NASA's Goddard Institute for Space Studies (GISS) in New York City, shows stricter vehicle emission standards would yield major health, agricultural, and climate benefits.

Shindell and colleagues used a comprehensive computer model and climate simulator — one of the first capable of accounting for the role of short-lived particles expelled in vehicle fumes called aerosols — that shows vehicle fumes exact an enormous toll in all countries and especially in the developing world.
The scientists used modeling techniques developed at GISS to compare a baseline scenario that assumes existing emission standards remain unchanged in coming decades with a second scenario that has most countries adopting stringent standards similar to those in place in Europe and North America. Vehicles in those two regions produce less particulate matter and less polluting gases, such as nitrous oxides and carbon monoxide, due to the use of particle filters and cleaner-burning fuels.

The aggressive scenario assumes, for example, that China, India, and Brazil adopt "Euro 6" standards by 2015, a regime that would reduce emissions of particulate matter by about 85 percent, nitrogen oxides by about 65 percent, and carbon monoxide by about 70 percent for passenger vehicles. The aggressive scenario assumes major emissions reductions in Latin America, Africa, and the Middle East, the regions with the laxest emissions standards. Emissions rules in North America are slightly more stringent than European standards already, so in North America the baseline and aggressive scenarios were identical.

The team's findings were published this week in the inaugural edition of Nature Climate Change.

Human toll, plant toll

Particulate matter from vehicle fumes can slip past the body's defenses — hair-like structures in the respiratory tract and hairs in our noses — and penetrate deep into the lungs. There, it can spark a range of diseases such as asthma, cardiovascular disease, and bronchitis.

Ozone, the product of reactions between nitrogen oxides, carbon monoxide or hydrocarbons, and sunlight, can harm both people and plants. In humans, it inflames the lining of air passages making breathing more difficult and can scar lungs after long periods of exposure. In crops, it damages cell membranes, slowing photosynthesis and reducing yields.

"The adoption of aggressive standards by 2015 would set the world on a course to prevent the deaths of 200,000 people, save 13 million tons of cereal grains from ozone damage, and save $1.5 trillion in health damages each year after 2030," Shindell said.

After five years, that would amount to saving a million lives, more than 50 million tons of food, and $7.5 trillion in human health damages. Health damages are based on an accounting technique economists use to weigh the benefits of life-saving regulations called the “value of a statistical life.”

For comparison, the United Nations estimated that the earthquake and tsunami that struck the northeast coast of Honshu had caused about 27,600 deaths and produced between $185 and $308 billion in damages at the end of March. Hurricane Katrina killed 1,836 people and produced about $81 billion in damages.

The analysis also breaks down potential health benefits by region and finds benefits varied widely. Overall, the modeling found that stricter standards would prevent the most deaths in China, India, and North Africa, regions where unfiltered soot-producing diesel engines remain ubiquitous.

While reductions in particulate matter tend to produce local health benefits, the scientists found health and agricultural benefits from reduced ozone disperse more widely. That means for some countries — India, for example — changes in emissions from neighboring countries could have as much impact as local emission changes.

"There is no one-size-fits-all approach to emissions standards. Different countries are going to need different approaches," Shindell said.

A climate connection

The new study shows that the same measures that benefit human health and agriculture would also make a significant dent in climate change in the near term.

While it is well-established that carbon dioxide released by vehicles contributes to global warming, it has been much less clear how the combination of shorter-lived aerosol particles vented by vehicles — such as black carbon, sulfate, and organic carbon — affect climate.

While some of these aerosols reflect sunlight and produce a cooling effect, others absorb light and warm the atmosphere. Aerosols from vehicles can also impact the development of clouds in ways that have poorly-understood consequences for climate.

Shindell's modeling shows that stringent emissions standards would reduce .20 °C (.36 °F) of warming in the Northern Hemisphere from 2040 to 2070. That's largely because more stringent standards would reduce emissions of black carbon, a constituent of soot, and carbon monoxide, a precursor of ozone. In comparison, the Northern Hemisphere has warmed by about .3 °C (.54 °F) per decade in the last three decades.

"Though the stringent standards would provide a clear climate benefit in the near term, the impact of accumulating carbon dioxide from vehicles is so large that there would still be an overall warming impact from vehicle emissions, albeit a lesser one than if they were not enacted," Shindell said.

Soot readily absorbs sunlight causing the atmosphere to warm. It also accelerates warming by coating the surfaces of snow and ice and reducing their reflectivity. Likewise, ozone, a greenhouse gas, warms the Earth.

As with the health benefits, the model projects the climate impacts of more stringent standards would vary significantly depending on the region. Cooling effects of sulfates, which highly are reflective, are minimized over parts of the Earth such as ice sheets and deserts that are also highly reflective, while the same areas exaggerate the warming from soot.

Emissions from India, for example, produced a particularly strong regional warming response because of the close proximity of large swaths of snow and ice in the Himalayas. The same was true of the Middle East and North Africa because of deserts in the region.
[Ozone, produced by chemical reactions between vehicle exhaust and sunlight, damages crops and reduces yields.

Credit: NASA Goddard's Scientific Visualization Studio]

To date, most studies have looked at the health, agricultural, or climate impacts of emissions in isolation. Shindell's analysis is one of the first to analyze the closely-intertwined impacts together — an approach that is more realistic.

"This is exactly the kind of study that is needed for policy-makers. Take a real policy scenario, and examine the impacts on a whole range of issues — air pollution, climate, crops, etc. and then use those results to find win-win solutions across very varied regions," noted Gavin Schmidt, another climatologist based at GISS.

More . .


Twitter Delicious Facebook Digg Stumbleupon Favorites More