ACOM in the News

Wednesday, August 30, 2017 - 11:59am
An illustration of an asteroid impacting earth. (Credit: NASA)

Tremendous amounts of soot, lofted into the air from global wildfires following a massive asteroid strike 66 million years ago, would have plunged Earth into darkness for nearly two years, new research finds. This would have shut down photosynthesis, drastically cooled the planet, and contributed to the mass extinction that marked the end of the age of dinosaurs.

The news article by NCAR science writer Laura Snider highlights recent work by ACOM scientists Charles Bardeen, Rolando Garcia, and Andrew Conley.

Tuesday, August 22, 2017 - 4:32pm
Total solar eclipse at Casper Mountain, Wyoming on August 21, 2017. Photo credit: Keon Gibson, NCAR

CASPER MOUNTAIN. — It’s nothing like a sunset. It’s cold and dark, but it’s not like nighttime, or even twilight. The moon just snaps into place over the last slivers of the sun, turning the sun into a dark hole. The only illumination — a flat, ghostly, metallic sort of light — is from peaked gossamer streamers stretching out toward the edges of the sky.

Read more by astronomy writer Lisa Grossman at Science News - August 21, 2017.

Thursday, June 29, 2017 - 3:40pm
Figure 1 of Buchholz et al 2017

Measurements of carbon dioxide from the MOPITT satellite instrument have been validated using the NDACC network of ground-based measurements. ACOM scientist Rebecca Buchholz and colleagues reported on their study of MOPITT version 6 retrievals using total column CO measurements from ground-based remote-sensing Fourier transform infrared spectrometers (FTSs). MOPITT generally shows a small bias with respect to the ground-based measurements. The ground stations are located worldwide at latitudes ranging from 80° N to 78° S, and are maintained by the Network for the Detection of Atmospheric Composition Change (NDACC).


Buchholz, R. R., Deeter, M. N., Worden, H. M., Gille, J., Edwards, D. P., Hannigan, J. W., Jones, N. B., Paton-Walsh, C., Griffith, D. W. T., Smale, D., Robinson, J., Strong, K., Conway, S., Sussmann, R., Hase, F., Blumenstock, T., Mahieu, E., and Langerock, B.: Validation of MOPITT carbon monoxide using ground-based Fourier transform infrared spectrometer data from NDACC, Atmos. Meas. Tech., 10, 1927-1956,, 2017.

Quantifying Fire Emissions & Associated Aerosol Species using Assimilation of Satellite Carbon Monoxide Retrievals
Friday, May 5, 2017 - 2:35pm

Wildfires tend to be more intense and hence costly and are predicted to increase in frequency under a warming climate. For example, the recent August 2015 Washington State fires were the largest in the state’s history. Such large fires impact not only the local environment but also affect air quality far downwind through the long-range transport of pollutants. Global to continental scale coverage showing the evolution of CO resulting from fire emission is available from satellite observations. Carbon monoxide is the only atmospheric trace gas for which satellite multispectral retrievals have demonstrated reliable independent profile information close to the surface and also higher in the free troposphere. The unique CO profile product from Terra/MOPITT clearly distinguishes near-surface CO from the free troposphere CO. Also previous studies have suggested strong correlations between primary emissions of fire organic and black carbon aerosols and CO. We used the Ensemble Adjustment Kalman Filter (DART) system to assimilate MOPITT CO profiles and MODIS Aerosol Optical Depth in the global scale chemistry-climate model CAM-chem. The ensemble technique allows inference of additional model parameters such as CO emissions, as well as emissions of aerosol species resulting from fires such as organic and black carbon.

In a case study of the August 2015 wildfires in Washington, the assimilation of MOPITT CO and MODIS AOD was used to infer corrections to the fire emissions of CO, black carbon and organic carbon using the ensemble information. The a priori emissions (based on FINN) were increased by a factor of about 3.5 for the WA fires.  Subsequent assimilation of the MOPITT CO profile can also be used to constrain the aerosol profile.


Relative average differences in Organic Carbon + Black Carbon across
North America from 20-31 Aug. 2015 compared to the Control Run

Reductions in Anthropogenic Carbon Monoxide Emissions Lead to Shorter Methane Lifetimes in the Atmosphere
Friday, May 5, 2017 - 2:27pm

About half of atmospheric carbon monoxide (CO) is from direct (CO) emissions that are due to incomplete combustion and are related to both natural (e.g. wildfires) and anthropogenic activities. The remainder of CO in the atmosphere is produced from the chemical oxidation of hydrocarbons, mainly from biogenic sources and methane (CH4). Since most of the hydrocarbons, CO, and CH4 in the atmosphere are oxidized by the hydroxyl radical (OH), the associated chemical lifetimes of these species are strongly coupled with OH. For example, a reduction in CO emissions leads to more OH and therefore a shorter CH4 lifetime, assuming CH4 emissions are the same. This means that long-lived greenhouse gases such as CH4 are linked with short-lived pollutants related to air quality. We use the NCAR coupled chemistry-climate model of the Community Earth System Model (or CESM Community Atmospheric Model with Chemistry (or CAM-Chem, ) to investigate the coupled nature of our chemical system through a decadal chemical reanalysis experiments. We assimilate weather observations and satellite-based measurements of CO from The Measurement of the Pollution in the Troposphere (MOPITT, across the recent decade (2002-2013) using the Data Assimilation Research Testbed (DART,

Based on these experiments, we confirm previous reports of decreasing trends in global CO burden that is mainly attributed to the reduction of CO emissions from anthropogenic sources.  However, the impact of this reduction in CO on CH4 chemical loss is not clear at this juncture. The rate of CH4 loss is dependent upon CH4 abundance and OH concentrations. It is also evident from atmospheric CH4 observations that the increase in CH4 sources leads to a positive growth rate of CH4 abundance over the recent decade and therefore leading to a positive trend in the absolute magnitude of CH4 chemical loss. As a consequence, this increase in CH4 loss leads to a positive trend in the chemical production of CO (secondary CO). From our reanalysis, we find that the other sources of secondary CO from biogenic sources (represented here as isoprene which is most important hydrocarbon emitted from vegetation), exhibits no significant trend.  Since the chemical lifetime of CH4 is inversely proportional to OH (where its main sink is CO), we infer from our analysis that during this period of long-term decline of CO abundance (mainly from changes in anthropogenic CO emissions), it is likely that we observed a reduced rate of increase in CH4 abundance and loss than in a scenario where CO emissions are the same. These results show the potential cobenefits of reducing both CO and CH4 emissions to mitigate climate and air pollution impacts.

Top panel: Monthly anomalies of globally integrated emissions of isoprene (Tg Isoprene/Month) as well as
tropospheric columns of chemical fluxes (in Tg(molecule)/Month)
estimated from the NCAR-MOPITT Reanalysis

Reference:  Gaubert, B., Arellano, A. F., Barré, J., Worden, H. M., Emmons, L. K., Tilmes, S., Buchholz, R. R., Vitt, F., Raeder, K., Collins, N., Anderson, J. L., Wiedinmyer, C., Martinez Alonso, S., Edwards, D. P., Andreae, M. O., Hannigan, J. W., Petri, C., Strong, K., and Jones, N.: Toward a chemical reanalysis in a coupled chemistry-climate model: An evaluation of MOPITT CO assimilation and its impact on tropospheric composition, J. Geophys. Res.-Atmos., doi:10.1002/2016JD024863,, 2016JD024863, 2016.

Thursday, April 6, 2017 - 1:56pm

In celebration of Air Quality Awareness week, NCAR is hosting an open house featuring information and family friendly activities about air quality. Learn from experts about air quality, how we measure and research it, and how it impacts humans, plants, and animals. NCAR’s new air quality exhibit will also be featured. Bring questions and mingle with scientists and experts from NCAR, NASA, the National Park Service, the Regional Air Quality Council, the University of Colorado, Boulder County Public Health, Colorado Department of Health and Environment, GO3-The Global Ozone Project, and Ball Aerospace. Local organizations will showcase activities and resources.

ACOM Scientists will be present to discuss The Front Range Air Pollution and Photochemistry Experiment – FRAPPÉ – which aims to characterize and understand summertime air quality in the Northern Front Range Metropolitan Area (NFRMA).

This event is free and open to the public, all ages are welcome. The open house is 5 pm until 8pm on May 3, 2017 at the NCAR Mesa Lab (1850 Table Mesa Drive, Boulder, CO 80305).

Tuesday, April 4, 2017 - 10:48am

With world leaders agreeing to try to limit the increase in global temperatures, scientists at the National Center for Atmospheric Research (NCAR) are taking a look at whether geoengineering the climate could counter enough warming to help meet that goal. "One thing that surprised me about this study is how much geoengineering it would take to stay within 2 degrees if we don't start reducing greenhouse gases soon," said ACOM scientist Simone Tilmes, the lead author.

Thursday, March 23, 2017 - 10:00am
An image taken from space of smoke billowing from fires in Jambi Province on the Indonesian island of Sumatra. The false-color image was made with a combination of visible (green) and infrared light so that fires and freshly burned land stand out. (Image courtesy NASA.)

2015 wildfires linked to as many as 17,270 premature deaths

ACOM scientist Christine Wiedinmyer is a co-author of a new study into the health effects of the 2015 Indonesian wildfires. This is an excerpt from a news release issued by Newcastle University.

Wildfires in Indonesia and Borneo exposed 69 million people to unhealthy air pollution, new research has shown.

The study, published today in Scientific Reports, gives the most accurate picture yet of the impact on human health of the wildfires which ripped through forest and peatland in Equatorial Asia during the autumn of 2015.

Wednesday, July 6, 2016 - 9:56am
This animation shows the opening and closing of the Antarctic ozone hole (dark blue) in 2015. (Animation courtesy of NASA.)

Susan Solomon at MIT, along with ACOM scientists Doug Kinnison and Michael Mills, have identified the “first fingerprints of healing” of the Antarctic ozone layer, published on June 30, 2016 in the journal Science. The research was covered by BBC Science.

The research team found that the September ozone hole has shrunk by more than 4 million square kilometers — about half the area of the contiguous United States — since 2000, when ozone depletion was at its peak. They also showed for the first time that this recovery has slowed somewhat at times, due to the effects of volcanic eruptions from year to year. Overall, however, the ozone hole appears to be on a healing path.

The other paper co-authors are Diane Ivy of MIT, Ryan Neely of the University of Leeds, and Anja Schmidt of the University of Leeds.

Friday, May 13, 2016 - 10:26am
From left: ACOM scientists Sam Hall, Benjamin Gaubert, Pablo Saide, Deedee Montzka, Louisa Emmons, and Andy Weinheimer. (Photo courtesy Sam Hall, ACOM)

Between May 1 and June 12, 2016, ACOM scientists and their colleagues from NASA, U.S. and South Korean universities, and South Korea’s National Institute of Environmental Research (NIER) will collect observations from airborne labs, ships, satellites, and ground-based instruments. The campaign, which involves more than 580 researchers from 72 institutions, is called KORUS-AQ (Korea U.S.-Air Quality study).

Wednesday, February 17, 2016 - 11:58am
Asteroids passing earth - Discovery News, February 10, 2016

Discovery News: A strike by a medium-size asteroid in a forested region could change the Earth’s climate to ice-age like conditions with effects lasting for up to 10 years. Airborne soot and dust aerosols would decrease the amount of sunlight reaching the Earth’s surface, which would cause significant surface cooling, reduce precipitation and could threaten global food supplies, says ACOM's Chuck Bardeen. The impact study was carried out using the WACCM atmospheric model.

Wednesday, January 20, 2016 - 2:43pm
University of Maryland chemistry graduate student Julie Nicely provides real-time analysis of data collected off the coast of Guam. Photo credit: Ross Salawitch published an article about ACOM's CONTRAST field campaign that operated out of Guam during January and February 2014. Biomass burning in the equatorial regions of Africa and Asia causes pockets of high ozone over the western Pacific Ocean. ACOM scientist Laura Pan was a Principal Investigator for CONTRAST, and Doug Kinnison explained how NCAR's CAM-Chem model provided forecast and analysis.

Tuesday, December 8, 2015 - 4:37pm
Image credit: NASA/Steele Hill

A research paper co-authored by ACOM scientist Dan Marsh was featured in Eos. The paper describes how WACCM version 4 produces a stronger vertical circulation in the earth's atmosphere, bringing NO and NO2 down into the stratosphere over Antarctica and destroying ozone there. WACCM4 provides the basis for new studies that may increase our understanding of the sun’s impact on climate. The original paper "Simulated solar cycle effects on the middle atmosphere: WACCM3 Versus WACCM4" was published in Journal of Advances in Modeling Earth System (June 2015).

Monday, October 26, 2015 - 8:29am
Panorama of Boulder, Colorado taken from just south of Fairview High School. Photo by Hustvedt at Wikimedia Commons.

The SPARC regional workshop on “Chemical and Physical Processes in the Climate System" will be held on 9-10 November 2015 at the National Center for Atmospheric Research in Boulder, Colorado, back-to-back with the SPARC Scientific Steering Group (SSG) meeting (10-13 November 2015).

Thursday, October 22, 2015 - 10:26am
Geostationary satellite

October 21, 2015 | ACOM scientists Jerome Barre, David Edwards, and Helen Worden have demonstrated how new types of satellite data could improve how agencies monitor and forecast air quality, both globally and by region. The new satellite observations would significantly improve air pollution forecasts.

The scientists used computer simulations to test a method that combines analysis of chemistry-climate model output with the kind of data that could be obtained from a planned fleet of geostationary satellites, each of which would view a large area of Earth on a continuous basis from high orbit.

"We think the new perspective made possible by geostationary sensors would provide data that is useful for everyday air quality forecasting, as well as for early warnings about extreme events, like the effects of wildfires," said Helen Worden.

Read more at UCAR AtmosNews...

Monday, September 21, 2015 - 2:28pm
Christine Wiedinmyer

ACOM scientist Christine Wiedinmyer was quoted in an editorial in the Wall Street Journal about carbon emissions from the recent wildfires in California. She estimated that southern California fires burning for one week produced as much carbon dioxide as a quarter of the state’s monthly fossil-fuel emissions. (September 16, 2015)

Thursday, February 5, 2015 - 11:24am
Image of sunlight scattered by cosmic dust, courtesy of ESO/Y. Beletky

A scientific paper by Chester Gardner, Alan Liu, ACD Scientist Dan Marsh, Wuhu Feng, and J. M. C. Plane has been selected by the American Geophysical Union as an "AGU Research Spotlight." Inferring the global cosmic dust in flux to the Earth’s atmosphere from lidar observations of the vertical flux of mesospheric Na (2014) was published in the Journal of Geophysical Research: Space Physics. The research studied the meteoric debris that enters the Earth's atmosphere and is eventually transported to the surface.

Thursday, September 25, 2014 - 1:39pm
Gabi Pfister discusses ozone with CCTV and Hendrik Sybrandy

Hendrik Sybrandy of CCTV reports with Gabriele Pfister on the recent ACD FRAPPÉ study funded by the U.S. state of Colorado. FRAPPÉ embarks on a new study of ozone. The pollutant, a key component of smog, has been shown to cause health problems and to damage crops. This comprehensive effort could help countries around the world tackle their future pollution problems. The video at YouTube is 2:22 minutes long (published Jul 20, 2014).

Monday, July 28, 2014 - 3:30pm
Frank Flocke of ACD with Marty Coniglio of 9News

Marty Coniglio chats with ACD's Frank Flocke about the NCAR planes testing ozone pollution (July 25). The news video is 5 minutes long and includes interior shots of the instrumentation used aboard the research aircraft.

Thursday, July 17, 2014 - 1:40pm
CONTRAST science and flight team with research aircraft in Guam.

Scientific American reports:
Hundreds of years after humans mastered the art of chimney venting so they could heat their houses, scientists have undertaken a major research project to better understand how Earth’s atmosphere uses its very own version of a chimney. More than 40 researchers recently visited a sparsely populated part of the western tropical Pacific Ocean—near the island of Guam—known as the “global chimney.” The area boasts the world’s warmest ocean temperatures and vents massive volumes of warm gases from the surface high into the atmosphere, which may shape global climate and air chemistry enough to impact billions of people worldwide.

Friday, June 13, 2014 - 11:33am
FRAPPÉ logo cropped

The Boulder Daily Camera reports:
It sounds like a delectable dessert; but in fact, ACD's FRAPPÉ field campaign is an ambitious effort to gather thorough data on all the pollutants that appear in the atmosphere over the Front Range during the summer months and prevent the metro area from meeting federal air quality standards. "Something this comprehensive, such a major campaign, has not happened in the Front Range before," said Gabriele Pfister, an atmospheric scientist for NCAR. She and NCAR's Frank Flocke are the study's two principal investigators.

Thursday, February 20, 2014 - 9:48am
Factory in China on the Yangtze River; photo by High Contrast at Wikimedia Commons.

Postdoctoral fellow Ryan Neely published a paper in the Journal of Geophysical Research that links combustion of coal, oil, and biomass to a layer of sulfates high above Asia. The work was done within and motivated by other studies within NESL's Atmospheric Chemistry Division. (February 20, 2014)

Friday, January 31, 2014 - 8:50am
Convection over Guam during CONTRAST; photo by Shawn Honomichl.

The Baltimore Sun reports the ongoing CONTRAST field campaign taking place in Guam. Flights by three research aircraft allow scientists from NCAR's Atmospheric Chemistry Division, the University of Miami, and the University of Maryland to study the effects of tropical thunderstorms on the atmosphere, as towering cumulus clouds loft surface air high over the warm Pacific ocean. (January 24, 2014)

Friday, January 10, 2014 - 11:00am

Christine WiedinmyerACD scientist Christine Wiedinmyer has been invited to speak at the upcoming meeting of the American Meteorological Society in Atlanta, Georgia during 2-6 February 2014. She will deliver the Walter Orr Roberts lecture for 2014: “Fire in the Earth System: Interactions with the Atmosphere.” Congratulation, Christine! If you are going to the AMS meeting, please plan to attend her presentation on Wednesday, 5 February, 5:00–6:00 p.m.

Wednesday, September 4, 2013 - 2:24pm
Mother Jones screen shot of NASA DC-8

Tim McDonnell and James West of Climate Desk were invited to fly along with the NASA DC-8 on a SEAC4RS mission to investigate and measure clouds. The resulting video published at Mother Jones magazine shows the on-board equipment used within the cramped space of the cabin. Scientists in flight keep busy monitoring levels of aerosols, solar radiation, CO2, biogenic emissions, and other atmospheric chemicals. (published September 4, 2014)

Friday, July 19, 2013 - 12:34pm

Mary BarthACD scientist Mary Barth was interviewed by Inside Science TV about the DC3 field campaign that took place during summer 2012. Pollutants and chemicals near the earth's surface are transported aloft into the upper atmosphere. Barth said researchers want to learn how the thunderstorms may be affecting the concentration of ozone—a significant factor in air pollution. (published July 9, 2013)

Monday, July 8, 2013 - 1:31pm

Nepal, Kathmandu: by Steve Evans from Citizen of the WorldACD scientist Laura Pan recently organized a scientific workshop in Kathmandu, Nepal to study the Asian summer monsoon. The ACAM workshop brought together 120 scientists representing 17 countries to discuss the effects of air pollution on the monsoon and rainfall patterns across Asia. The other workshop chairs were Jim Crawford of NASA Langley and Arnico Panday of ICIMOD in Nepal. SciDevNet covered the ACAM workshop in a news story on July 5, 2013.

Wednesday, June 19, 2013 - 9:37am

Christine WiedinmyerACD scientist Christine Wiedinmyer spoke with Ryan Warner on Colorado Public Radio about the Black Forest wildfire near Colorado Springs. The smoke and particles from fires can affect air quality and visibility. (broadcast June 17, 2013)

Monday, August 21, 2017 - 1:00pm
Illustration of asteroid impactTremendous amounts of soot, lofted into the air from global wildfires following a massive asteroid strike 66 million years ago, would have plunged Earth into darkness for nearly two years, new research finds.

Thursday, July 20, 2017 - 2:53pm
A solar eclipse in 1998NCAR scientists plan to use the total eclipse on Aug. 21 to comprehensively measure, for the first time, the infrared radiation streaming out from the Sun's corona.

Wednesday, November 16, 2016 - 9:31am
2015 wildfires in Sumatra, as seen from spaceWildfires in Indonesia and Borneo exposed 69 million people to unhealthy air pollution, new research has shown.




ACOM | Atmospheric Chemistry Observations & Modeling