Cooperative Institute for Research in Environmental Sciences

The natural biological resilience of freshwater species likely spared them from the otherwise devastating effects of the Chicxulub asteroid impact 66 million years ago, which had caused massive extinction in terrestrial and marine environments. 

When the Manhattan-sized asteroid slammed into Earth, it created an “impact winter,” a mass of dust and smoke in the atmosphere that blocked sunlight from reaching Earth’s sunlight for one or two years. The enduring lack of sunshine and cool temperatures meant a loss of phytoplankton, but CIRES scientist Douglas Robertson and his team propose that freshwater ecosystems proved more resilient to the sudden change. Freshwater species are often adapted to annual freeze-thaw cycles and would have held up better to the impact winter conditions. Fast-flowing streams could have reoxygenated inland waterways and organic matter could have been supplied by surface runoff. Furthermore, since many freshwater organisms have dormant stages they would have been able to wait out the inclement conditions imposed by the asteroid. 

The study was published online in July in the Journal of Geophysical Research Biogeosciences 

Douglas Robertson,, 303-682-2478

Media Contact: Kathleen Human,, 303-735-0196

2012 a record year; Arctic reaches milestone level of carbon dioxide

NOAA’s updated Annual Greenhouse Gas Index (AGGI), which measures the direct climate influence of many heat-trapping gases like carbon dioxide and methane, shows 2012 continued the steady upward trend that began with the Industrial Revolution of the 1880s.

Driven in good part by rising levels of carbon dioxide (CO2), the AGGI reached 1.32 in 2012, meaning the combined heating effect of long-lasting, human-caused emissions with that of existing gases trapped in the atmosphere has increased by 32 percent since 1990, the baseline year for the index.

Although no other gas currently contributes to warming more than carbon dioxide, the AGGI includes measurements of methane and nitrous oxide, gases emitted by both human activities and natural sources. It also includes several chemicals known to deplete Earth’s protective ozone layer, which are also active as greenhouse gases.

"2012 was not a surprise. This Index—a highly-sought and respected tool for researchers—shows that the world is getting warmer because of our continued emissions of these long-living, heat trapping gases," said Jim Butler, director of the Global Monitoring Division of NOAA’s Boulder-based Earth System Research Laboratory (ESRL). "This Index provides scientists and decision makers alike with information useful for understanding climate change and it’s present-day and potential future impacts on our communities.”

Scientists at ESRL calculate the AGGI each year from atmospheric data collected through an international cooperative air-sampling network of about 80 sites around the world. Researchers from CIRES, the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder, are involved at many stages: from shipping flasks around the world to air sampling and data analysis.

Last year, CO2 at the peak of its cycle reached 400 ppm for one month at all eight Arctic sites for the first time. (This year, peak CO2 values at Mauna Loa—considered our “global benchmark” site— exceeded 400 ppm)

The AGGI is analogous to the dial on an electric blanket. Just as the dial does not tell you exactly how hot you will get, the AGGI does not predict how much Earth’s climate will warm. You do know, however, that if the dial is turned up a little, the blanket will get warmer—and not immediately. If you turn it up a lot, you know the blanket will get a lot warmer—eventually.

“At this rate of emissions, the global average will shortly reach 400 ppm and, within 4 to 5 years, the South Pole,” added Butler. “We anticipate this number will steadily rise with continued emissions in the 21st century, with the remote Arctic sites likely to be the last to see CO2 values in the 300s, as plants in high latitudes scale back on natural emissions of CO2 emissions earlier in summertime. This steady rise of CO2, along with contributions from other gases, will continue to drive the AGGI upward.”

NOAA researchers developed the AGGI in 2004 and have updated it annually since. Although it currently is calculated for years starting in 1978, atmospheric composition data from ice core and other records could allow the record to be extended back centuries. To learn more about the index, visit:

CIRES is a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado Boulder.

Information and Graphics:
Download the image here: [ 1 ]

Katy Human, CIRES Communications Director, 303-735-0196,
John Ewald, NOAA Public Affairs, 240-429-6127,

New measurements made on one day suggest a need for more direct data

On a perfect winter day in Utah’s Uintah County in 2012, CIRES scientists and NOAA colleagues tested out a new way to measure methane emissions from a natural gas production field. Their results, accepted for publication in Geophysical Research Letters, constitute a proof-of-concept that could help both researchers and regulators better determine how much of the greenhouse gas and other air pollutants leak from oil and gas fields. The measurements show that on one February day in the Uintah Basin, the natural gas field leaked 6 to 12 percent of the methane produced, on average, on February days.

“We used a mass balance technique, which means we follow an air mass as it moves into the region and then flows out,” said Colm Sweeney, a scientist with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder, who leads the aircraft group at NOAA’s Earth System Research Laboratory Global Monitoring Division. “We look at the difference in methane between those two to determine an actual emissions rate for the region.”

CIRES, NOAA and other scientists have used this type of atmospheric mass balance accounting technique in many other settings—to determine power plant emissions, for example, and the atmospheric impacts of refineries and cities, said Anna Karion, lead author of the new paper and a CIRES atmospheric scientist who also works at NOAA.

In Utah’s Uintah Basin, on one day during a weeks-long field campaign in 2012, weather conditions were near ideal for testing the technique in an oil and gas field, Karion said. Late on February 2, a weather front passed through, with high winds that swept clean the atmosphere above the Uintah Basin, south of Vernal, Utah.

“Then the next day, the winds decreased to about 12 miles per hour, and they held very steady for hours,” Karion said.

When the winds settled down on February 3, a pilot flew a single-engine Mooney TLS aircraft, carrying sophisticated instruments for measuring methane and other atmospheric gases, back and forth in the Uintah Basin. The aircraft measurements let scientists calculate the total amount of methane added to the air mass as it transited the basin. Combining those data with precise measurements of wind speed, made by NOAA colleagues using a ground-based laser, scientists could calculate the methane emission for the whole basin.

The team determined that methane emissions from the oil and natural gas fields in Uintah County totaled about 55,000 kg (more than 120,000 lbs) an hour on the day of the flight. That emission rate is about 6 to 12 percent of the average hourly natural gas production in Uintah County during the month of February.

A recent federal report estimated that methane’s leak rate, nationally, is less than 1 percent of production; another report noted that emissions in the Uintah (“Uinta”) Basin, which produces about 1 percent of total U.S. natural gas, may have higher emissions than typical for western gas fields. The Environmental Protection Agency’s Office of Inspector General has called for better emissions data from the natural gas sector, and this paper is one of the first published since.

The aircraft was part of a collaborative, multi-agency mission in the region to better understand how emissions from fossil fuel extraction activities affect local air quality. Methane is the primary constituent of natural gas, and it is a potent greenhouse gas. Other components, such as chemicals called volatile organic compounds are also emitted from oil and gas production operations and can contribute to ozone pollution.

“We expected methane emissions would be detectable, but we did not anticipate levels as high as what we observed,” Sweeney said.

The aircraft flew over the oil and gas field 11 other days during the study, but on those days, wind and other atmospheric conditions were unpredictable or erratic making it difficult to directly estimate methane emissions.

Karion, Sweeney and their co-authors continue to analyze methane and other emissions data gathered in Uintah Basin, in 2012 and 2013, and from recent scientific flights through other oil and gas production regions.

Utah’s Division of Air Quality helped to fund some of the Utah work, and Deputy Director Brock LeBaron said that new actions already taken by the EPA and the state of Utah will soon lessen methane emissions in the Uintah Basin.

“Our work with NOAA and CIRES indicates that high levels of volatile organic compounds contribute to ozone pollution in the Uintah Basin,” LeBaron said. “Our own efforts in Utah and the EPA’s oil and gas New Source Performance Standards, designed to lessen those air quality impacts, will also significantly cut methane emissions during the next few years.”

CIRES is a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado Boulder.

Coauthors of “Methane emissions estimate from airborne measurements over a western United States natural gas field” are Anna Karion, Colm Sweeney, Gabrielle Pétron, Gregory Frost, Jonathan Kofler, Ben R. Miller, Tim Newberger and Sonja Wolter of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder; Robert Banta, Alan Brewer, Ed Dlugokencky, Mike Hardesty, Patricia Lang, Stephen A. Montzka, Russell Schnell, Pieter Tans, Michael Trainer and Robert Zamora of NOAA’s Earth System Research Laboratory in Boulder, Colo.; and Stephen Conley of the University of California, Davis. Geophysical Research Letters is a journal of the American Geophysical Union.

Colm Sweeney, CIRES research scientist, 917-319-5015,
Katy Human, CIRES communications director, 303-735-0196,

Information and Graphics:

Download the image here: [ 1 ] [ 2 ] [ 3 ]

The Bulletin of the American Meteorological Society has published the 2012 State of the Climate report, which provides a detailed update on global climate indicators and notable weather events. Seven scientists from CIRES, the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder, and many others from NOAA contributed to this year’s report, which documented 2012 ranking as one of the top 10 warmest years on record for the globe.

The report, compiled by 384 scientists from 52 countries around the world, summarizes 2012 data representing diverse climatic and environmental indicators, such as:

  • Average and extreme temperatures
  • Precipitation levels and indications of drought
  • Sea-ice extent in the Arctic
  • Climate in Antarctica
  • Global cyclone activity
  • Levels of tropospheric ozone, an air pollutant

In 2012, global carbon dioxide emissions from fossil fuel combustion and cement production reached a record high, according to the new report. The previous report, by contrast, had documented a slight decline in global carbon dioxide emissions, reflecting the impact of the financial crisis. In 2012, atmospheric carbon dioxide concentrations also increased, to 392.6 parts per million (ppm); before the Industrial Revolution, they were 280 ppm. In spring 2012, for the first time, the atmospheric CO2 concentration exceeded 400 ppm at 7 of the 13 Arctic observation sites. CIRES researchers are involved in many aspects of NOAA’s long-term effort to monitor Earth’s atmosphere, helping to ship sample flasks around the world, analyze samples and evaluate trends.

Scientists at CIRES National Snow and Ice Data Center (NSIDC) helped to compile information on the Arctic for the 2012 report. The Arctic saw record low sea ice extent in September 2012, and the Northern Hemisphere snow cover extent in June also saw a record low. On July 11th and 12th, the Greenland ice sheet clocked a record melt event with 97 percent of the ice sheet showing some form of melt, four times greater than the average melt for this time of year. NSIDC provides scientific analysis on Arctic sea-ice conditions year round, making the data available to the global community. NSIDC scientists also provide daily information about surface melting on theGreenland ice sheet.

The 2012 edition of this peer-reviewed study is published in the Bulletin of the American Meteorological Society today. CIRES contributors to the report are Geoff Dutton, Dale Hurst and Cathy Miller, who work at NOAA’s Earth System Research Laboratory; Walt Meier and Ted Scambos from CIRES’ National Snow and Ice Data Center; and John Wahr, a past CIRES Fellow.

CIRES is a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado Boulder.

Ted Scambos, CIRES National Snow and Ice Data Center. Please contact him through NSIDC media:, 303-492-1497

Audio from the NOAA Media Call announcing key findings from the State of the Climate in 2012 report will be posted at this link later today:

Levels of carbon dioxide in the atmosphere rise and fall annually as plants take up the gas in spring and summer and release it in fall and winter through photosynthesis and respiration. Now the range of that cycle is growing as more CO2 is emitted from the burning of fossil fuels and other human activities, according to a study published in Science by Scripps Institution of Oceanography, UC San Diego, with CIRES and NOAA co-authors.

The findings are the result of a multi-year airborne survey of atmospheric chemistry called HIAPER Pole-to-Pole Observations (HIPPO). Observations of atmospheric CO2 made by aircraft at altitudes between 3 and 6 kilometers (10,000-20,000 feet) – combined with aircraft data from NOAA and CIRES – show that seasonal CO2 variations have substantially increased in amplitude over the last 50 years.

The amplitude increased by roughly 50 percent across high latitude regions north of 45° N, in comparison to previous aircraft observations from the late 1950s and early 1960s. This means that more carbon is accumulating in forests and other vegetation and soils in the Northern Hemisphere during the summer, and more carbon is being released in the fall and winter, said study lead author Heather Graven, a postdoctoral researcher in the Scripps CO2 Program led by geochemist Ralph Keeling.

It is not yet understood why the increase in seasonal amplitude of CO2 concentration is so large, but it is a clear signal of widespread changes in northern ecosystems.

“The atmospheric CO2 observations are important because they show the combined effect of ecological changes over large regions,” said Graven. “This reinforces ground-based studies that show substantial changes are occurring as a result of rising CO2 concentrations, warming temperatures, and changing land management, including the expansion of forests in some regions and the poleward migration of ecosystems.”

The study, “Enhanced seasonal exchange of CO2 by northern ecosystems since 1960,” appears in print editions of the journal Science on Aug. 30 and in Science Express Aug. 8. The National Science Foundation, the federal Department of Energy, the National Center for Atmospheric Research (NCAR), NOAA, and the Office of Naval Research funded the study.

The researchers compared recent aircraft data with older aircraft data gathered from 1958 to 1961 using U.S. Air Force weather reconnaissance flights and analyzed by Scripps geochemist Charles David Keeling, the father of Ralph Keeling. These aircraft measurements were done at the same time C.D. Keeling was beginning continuous CO2 measurements at Mauna Loa, Hawaii. While the Mauna Loa measurements are now recognized as the famous “Keeling Curve,” the early aircraft data were all but forgotten.

Carbon dioxide concentrations in the atmosphere varied between 170 and 280 parts per million over the past 800,000 years. By the time C.D. Keeling began collecting data at Mauna Loa in 1958, the concentration had risen to about 315 parts per million. In May 2013, daily CO2 measurements at Mauna Loa exceeded 400 parts per million for the first time in human history.

Recent observations aboard a modified Gulfstream V jet known as HIAPER were made during research flights conducted by NCAR with scientists from Scripps, Harvard, CIRES, NOAA, NCAR, and the University of Miami in the HIPPO campaign between 2009 and 2011. The aircraft repeatedly ascended and descended from a few hundred meters to roughly 12 kilometers (40,000 feet) between the North Pole and the coast of Antarctica to construct a unique snapshot of the chemical composition of the atmosphere.

Additional recent data comes from regular flights conducted at a network of locations by NOAA and CIRES. Increasing CO2 amplitude since 1960 had already been observed at two ground-based stations: Mauna Loa and Barrow, Alaska. Other stations operated by Scripps and NOAA only began measuring CO2 in the 1970s to 1990s. The aircraft-based observations uniquely show the large area in the northern high latitudes where CO2 amplitude increased strongly since 1960.

The reasons for the wider seasonal swings in CO2 concentration remain to be determined, said researchers. Even though plant activity can increase with warmer temperatures and higher CO2 concentrations, the change in CO2 amplitude over the last 50 years is larger than expected from these effects, the researchers said. CO2 concentration has increased by 23 percent and average temperature north of 30°N has increased by 1° C (1.8° F) since 1960. Additional factors may involve changes in the amount of carbon allocated to leaves, wood or roots; changes in the extent or species composition of the ecosystems; or changes in the timing of photosynthesis and respiration.

Simulating complex processes in terrestrial ecosystems with models is recognized to be a challenge, and the observed change in CO2 amplitude is larger than simulated by models used by the Intergovernmental Panel on Climate Change (IPCC). While this underestimate does not call into question the response of climate to CO2 concentration in the IPCC models, it does suggest that a better understanding of what happened over the last 50 years could improve projections of future ecosystem changes. The bottom line is that northern ecosystems appear to be behaving differently than they did 50 years ago, said study authors.

CIRES’ Colm Sweeney, who works at NOAA’s Earth System Research Laboratory (ESRL); and Pieter Tans of NOAA’s ESRL were other co-authors on the new paper, as were:Stephen Piper, Lisa Welp and Jonathan Bent of Scripps Oceanography; Prabir Patra of the Research Institute for Global Change in Yokohama, Japan; Britton Stephens of NCAR; Steven Wofsy, Bruce Daube and Gregory Santoni of Harvard University; John Kelley of the University of Alaska Fairbanks; and Eric Kort of the Jet Propulsion Laboratory.

Photos and video from the HIPPO flights are available at the project website,

CIRES is a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado Boulder.

On the Web:

Scientists have uncovered strong evidence that soot, or black carbon, sent into the air by a rapidly industrializing Europe, likely caused the abrupt retreat of mountain glaciers in the European Alps.

The research, published Sept. 2 in the Proceedings of the National Academy of Sciences, may help resolve a longstanding scientific debate about why the Alps glaciers retreated beginning in the 1860s, decades before global temperatures started rising again.

Thomas Painter, a snow and ice scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., is lead author of the study, and coauthors include Waleed Abdalati, Director of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder.

“Something was missing from the equation,” Painter said.

To investigate, he and his colleagues turned to history. In the decades following the 1850s, Europe was undergoing a powerful economic and atmospheric transformation spurred by industrialization. Residents, transportation, and, perhaps most importantly, industry in Western Europe began burning coal in earnest, spewing huge quantities of black carbon and other dark particles into the atmosphere.

When black carbon particles settle on snow, they darken the surface. This melts the snow and exposes the underlying glacier ice to sunlight and relatively warm air earlier in the year, allowing more and faster melt.

To determine how much black carbon was in the atmosphere and the snow when the Alps glaciers began to retreat, the researchers studied ice cores drilled from high up on several European mountain glaciers. By measuring the levels of carbon particles trapped in the ice core layers and taking into consideration modern observations of the distribution of pollutants in the Alps, they could estimate how much black carbon was deposited on glacial surfaces at lower elevations, where levels of black carbon tend to be highest. 

The team then ran computer models of glacier behavior, starting with recorded weather conditions and adding the impact of lower-elevation black carbon. By including this impact, the simulated glacier mass loss and timing were finally consistent with the historic record of glacial retreat, despite the cool temperatures of the time.

“This study uncovers some likely human fingerprints on our changing environment,” Abdalati said. "It’s a reminder that the actions we take have far-reaching impacts on the environment in which we live."

“We must now look closer at other regions on Earth, such as the Himalaya, to study the present-day impacts of black carbon on glaciers,” said Georg Kaser, a study co-author from the University of Innsbruck and lead author of the Working Group I Cryosphere chapter of the Intergovernmental Panel on Climate Change’s upcoming Fifth Assessment Report.


More contacts:

Information and Graphics:

Download the image here.

Four months of darkness, minus-30-degree temperatures, 40-mile-per-hour winds—just another day at the lab for the Chu Research Group. The lab just happens to be at McMurdo Station in Antarctica, where CIRES Fellow Xinzhao Chu and her team spend many months every year studying the polar atmosphere. Using remote-sensing technology called lidar (light detection and ranging), they use laser light to analyze the middle and upper atmosphere. Their research is shedding light on the planet’s weather patterns, climate processes, and even the fertilization of life on Earth with essential minerals, such as iron.

To collect year-round lidar observations, one scientist from the Chu group must stay through the winter at McMurdo, operating and maintaining the equipment; three students have wintered-over thus far. The United States Antarctic Program (USAP) requires these scientists to pass rigorous physical and psychological tests before they can winter-over (see sidebar: Are you fit enough?).

“The scientists sacrifice their personal lives and do extremely hard work to collect invaluable data to enable our studies,” Chu said.

That hard work has not gone unnoticed. In July, Chu received a Provost’s Faculty Achievement Award from the University of Colorado Boulder for her highly influential research on the upper atmosphere. Additionally, for three years in a row, students from Chu’s group have won first-place prizes in the poster competition at the prestigious Coupling, Energetics and Dynamics of Atmospheric Regions (CEDAR) Workshop sponsored by the National Science Foundation. Chihoko Yamashita won in 2011, Cao Chen in 2012, and Zhibin Yu in 2013. “As far as we know, this is the first time that the same group of students has won first place three years in a row,” Chu said.

Meet the faces behind the balaclava with these highlights from the Chu Research Group.

Are you fit enough?

Antarctica is the coldest, driest, windiest, and loneliest continent on Earth, with limited medical-care capability. So American scientists who want to work there first have to be deemed physically qualified—or be “PQed”—by the United States Antarctic Program. This involves passing rigorous medical, dental, and—for those wintering-over—psychological tests. The latter, with questions such as, “Do you ever hate yourself?”, can sometimes carry a cultural bias or language barrier for nonnative English speakers. The Chu group’s first winter-over candidate, from Taiwan, didn’t pass for this reason. Next to try was Zhibin Yu. “I took the PQ challenge, and I just tried to be myself when answering the questions,” Yu said. “There were more than 700 questions.” Yu passed and became the first team member to winter-over. “I’m happy I had a chance to serve our group,” he said.

Xinzhao Chu

CIRES Fellow and associate professor in the CU Boulder Department of Aerospace Engineering Science

Xinzhao Chu explores advanced spectroscopy principles, develops new lidar technologies, and studies the fundamental physical and chemical processes that govern the structure and dynamics of the whole atmosphere. In essence, this means using innovative lidar systems to better understand Earth’s atmosphere and space. From 1999 to 2005, Chu made lidar observations at the North Pole and the South Pole, the latter at Britain's Rothera Research Station. She first was stationed at McMurdo in 2010, and January 2013 marked Chu's seventh trip to Antarctica.

Field highlight

“Seeing the Antarctic wildlife, including seals, birds, and penguins, is a high point of the field work,” Chu said. On one occasion, four emperor penguins lined up alongside the plane to see her off on her trip home. “Every time you see a penguin, it lifts your spirits,” she said.

Wentao Huang

CIRES research scientist

Wentao Huang was instrumental in the successful development of several lidars and the deployment of a specialized instrument—the iron Boltzmann temperature lidar—to McMurdo Station. This enabled the surprising discovery of neutral iron atoms more than 100 miles high in the atmosphere.

Huang is currently characterizing the atmospheric iron and sodium layers, which can be influenced by climate as well as geomagnetic storms that impact satellites, power grids, and radio communication.

Iron-rich particles play a crucial role in Earth’s environment; they settle on land and water and can fertilize life by providing nutrients for plants and small animals. “Through this research, we will better understand the evolving atmosphere and its responses to anthropogenic and extraterrestrial impacts and, thus, better understand our future,” Huang said.

Field highlight

"I like the hospitality of the scientists and staff working in Antarctica and the diversity of the research concentrated in a relatively small region,” Huang said. “I also enjoy the 24-hour sunshine during summer visits, as well as the amazing landscape and unique weather."

Xian Lu

CIRES Postdoctoral Visiting Fellow

Although Xian Lu has not worked in Antarctica, she uses the data from there to investivate atmospheric waves, specifically gravity waves, thermal tides, and planetary waves. Like waves in the ocean, these ripples of air parcels play a key role in mixing air, transferring energy, and driving atmospheric circulation, thus affecting weather and climate.

Lu is using lidar, radar, and satellite data, as well as model simulations, to assess the origins, mechanisms, and impacts of these waves on polar atmospheric processes, space weather, and the behavior of the global atmosphere.

“Polar waves are believed to have distinct features from their counterparts at mid- and low-latitudes,” Lu said. “Until now, they have not been thoroughly studied in the polar region, yet they are fundamental to understanding atmospheric behavior.”

Zhibin Yu

Ph.D. Candidate in the Department of Aerospace Engineering Sciences

In 2011, Zhibin Yu became the first winter-over student for the McMurdo lidar campaign (and the first winter-over scientist in the last 20 years at McMurdo Station). He is modeling the iron layers found in the thermosphere (the layer of atmosphere that starts about 50 miles above Earth’s surface and extends 500 miles up).

“The most exciting things from the 2011 winter operation were some new scientific phenomena discovered by Dr. Chu from the data,” Yu said. “Because of the new sciences we discovered, it led to a new scientific direction—investigating neutral metal layers in the thermosphere.”

In 2013, Zhibin Yu was the CEDAR first-place winner for his poster, “Lidar observations and numerical modeling studies of thermospheric Fe/Fe+ layers.” Yu is currently developing a new model to study the mechanism by which neutral metal layers form in the thermosphere.

Field highlight

“It is a unique experience—four months polar day, four months polar night, and four months day and night,” Yu said. “I enjoyed my winter, and I’m excited about the science we’ve discovered. We got four publications out of the first year of data, and there will be more.”

John A. Smith

Ph.D. student in the Department of Aerospace Engineering Sciences

John Smith’s research focuses on the advancement of a special type of lidar technology—resonance-fluorescence lidar—to investigate the dynamic boundary between the atmosphere and space. “Many pressing science questions exist about how this region behaves and how it affects, and is affected by, the rest of the atmosphere,” Smith said.

Smith is currently working on realizing a mobile, single-beam “whole-atmosphere” lidar, which would be the first lidar capable of making routine measurements of wind and temperature contiguously through the whole atmospheric column.

Field highlight

“Participating in an Antarctic science mission was always a dream of mine, so when the opportunity presented itself back in November 2010, I seized it,” Smith said. “Working closely with passionate scientists and energetic support staff from such a diverse array of backgrounds was truly invigorating and a privilege. There were very few trails left unexplored by the time I left. My only regret was leaving before the arrival of the emperor penguins, which came waddling in across the airfield in droves shortly after I returned to Christchurch.”

Weichun Fong

Ph.D. student in the Department of Aerospace Engineering Sciences

As the third winter-over scientist at McMurdo, Fong made a new record of observing the iron layers up to about 105 miles in the thermosphere. Weichun Fong arrived in Antarctica in August 2012 and will be there through October 2013, braving through the austral winter (from March to September). At McMurdo, Fong studies the atmospheric thermal structure, including thermal tides, gravity waves, and annual temperature climatology. He currently is analyzing winter thermal tides based on the lidar data collected in 2011 and 2012.

“Temperature is an important parameter and also a key factor in understanding and monitoring climate change,” Fong said. “This is especially true in polar regions since it has been proven that they are more sensitive to global climate change than the equatorial areas.” Fong is also using the lidar data to validate current atmospheric models and provide ground-truth observations for satellite measurements of temperature.

Field highlight

"I am glad that I flew to McMurdo Station during late August last year, since during that time, the dark sky still dominates most of the day,” Fong said. “I saw the first aurora in my life and was amazed by the sky scattered with tons of stars during the lidar run."

Cao (Chris) Chen

Ph.D. student in the Department of Aerospace Engineering Sciences

While analyzing McMurdo Station lidar data, Cao Chen reported for the first time a special type of gravity wave event—called an inertia gravity wave (IGW) event—in the Antarctic mesosphere/lower thermosphere. His research has begun to show an unexpectedly high occurrence of such events above McMurdo, suggesting a significant gap in the understanding of the polar atmospheric dynamics. “Underestimated wave drag from such IGWs in polar regions may be responsible for the long-standing ‘cold pole’ problem—that is, a cold bias of Antarctic winter stratosphere temperature in many general circulation and chemistry climate models,” Chen said. Through his research, Chen hopes to help solve this problem by better defining the wave parameters used in models.

Additionally, “establishing a temperature record in a polar atmosphere from the stratosphere to the lower thermosphere, we can monitor climate change in the middle atmosphere,” he said. “Our observations provide ground-truth to the satellites and validate global circulation models, which are used to project the future state of our climate system.” In 2012, Chen was the CEDAR first-place winner for his poster “Inertia-gravity waves in Antarctica: A case study with simultaneous lidar and radar measurements at McMurdo (77.8° S, 166.7° E).”

Field highlight

"McMurdo is a great place to work because people here are very friendly, and they work hard to guarantee that science happens,” Chen said. “Also, the facility is very convenient, and we can do a lot of sports we like. I especially like playing indoor soccer with a bunch of people twice a week."

Bo Tan

Ph.D. recipient in the CU Boulder Department of Aerospace Engineering Sciences

Using the Chu group's Antarctic data and Whole Atmosphere Community Climate Model (WACCM) simulations, Bo Tan completed his Ph.D. on lidar, satellite, and modeling studies of global teleconnection patterns and the “cold problem“ in general circulation models. The latter refers to the tendency for models to show a global mean cold bias.

Brendan Roberts

Winter-over lidar engineer

Brendan Roberts earned his master of science degree in May 2012 from the University of Colorado Boulder. As a winter-over lidar engineer, he operated the iron Boltzmann lidar at McMurdo through the Antarctic winter in 2012 and collected numerous valuable data. Roberts completed the campaign’s first 48-hour solo data-collection run. “I am proud that many papers and conference posters created by the Chu group came from the data I collected,” Roberts said. “There was a general gap in atmospheric data at that latitude range, and the lidar system is helping to fill that in, improving atmospheric data coverage and models.”

Field highlight

"The best parts were camping on the ice shelf at McMurdo Sound, seeing the bright stars every time I opened the door at Arrival Heights where the lidar system was operated, and seeing the aurora for the first time,” Roberts said. “The lows were when the fresh food ran out about a month after the station switched over to winter operations and the flight crews returned to the United States, leaving us on our own for the season.” Sharing a small, dorm-size room with two roommates also took adjustment, he said. As for the cold, Roberts was surprised at how quickly the body acclimates. “Around the end of July, I was walking outside from building to building in minus-40-degree weather in only a sweatshirt and felt fine,” Roberts said. “Around the same time, the temperature rose to about minus 5 degrees, and I lay on the roof of the building to watch the stars and night sky. I was wearing only a hoodie and jeans, but it still seemed really warm!"

Nearly one in 10 U.S. watersheds is “stressed,” with demand for water exceeding natural supply, according to a new analysis of surface water in the United States.  What’s more, the lowest water flow seasons of recent years—times of great stress on rivers, streams, and sectors that use their waters—are likely to become typical as climates continue to warm.

“By midcentury, we expect to see less reliable surface water supplies in several regions of the United States,” said the study’s lead author, Kristen Averyt, associate director for science at the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder. “This is likely to create growing challenges for agriculture, electrical suppliers and municipalities, as there may be more demand for water and less to go around.”

Averyt and her colleagues evaluated supplies and demands on freshwater resources for each of the 2,103 watersheds in the continental United States, using a large suite of existing data sets.

They identified times of extreme water stress between 1999 and 2007, and they estimated future surface water stress—using existing climate projections—for every watershed. In the paper, published online in Environmental Research Letters on Sept. 17, the authors also diagnosed the reasons contributing to stress.

Across the United States, the team found that water supplies are already stressed (i.e., demands for water outstrip natural supplies) in 193 of the 2,103 watersheds examined. In addition, the researchers reported:

  1. The U.S. West is particularly vulnerable to water stress, for two reasons: 1) the differences between average demand and average supply are relatively small, so slight shifts in either supplies or demands can trigger stress, and 2) Western water users have long relied on imported and stored water to supplement natural supplies, in order to meet demands.
  2. In most parts of the country, agriculture requires the most water, and contributes most to water stress.
  3. In Southern California, thirsty cities are the greatest stress on the surface water system.
  4. In scattered locations, the cooling water needs of electric power plants represent the biggest demand on water.

“A single power plant has the potential to stress surface supplies in a local area,” said co-author James Meldrum, a researcher in the Western Water Assessment, a program of the National Oceanic and Atmospheric Administration (NOAA) and CIRES. It’s critical to understand how various sectors contribute to the stress on a water system, Meldrum said, because effective remedies depend on accurate diagnosis.

Agricultural and municipal demands are spread among many users, for example, allowing flexible changes in water use and efficiency of use. “But because power plant decisions are so capital intensive, they tend to be locked in for a long time,” Meldrum said. “With the potential for increasing water stress in the next few decades across parts of the United States, power plants—and our access to electricity —may be put at risk when water is not adequately considered in planning.”

The authors deliberately didn’t account for future changes in demand for freshwater. Rather, this analysis was designed to identify the sensitivity of U.S. watersheds to changes in surface water availability.

The researchers hope that the analysis will provide useful information for people reliant on surface waters. "We hope research like this helps us understand challenges we might face in building a more resilient future,” Meldrum said.

The research was funded by the Union of Concerned Scientists; NOAA, through the Western Water Assessment; and CIRES. Other co-authors are Peter Caldwell, Ge Sun, and Steve McNulty from the U.S. Department of Agriculture Forest Service at Raleigh, N.C.; Annette Huber-Lee from Tufts University, at Medford, Mass.; and Nadia Madden from the Union of Concerned Scientists, Cambridge, Mass.

CIRES is a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and CU Boulder.


Information and Graphics:

Download the images: [ 1 ] [ 2 ] [ 3 ] [ 4 ]

A new study shows that water vapor high in the sky and the temperature at the Earth‘s surface are linked in a “feedback loop” that further warms our climate. Published today, this study gives the first estimate of the size of the feedback‘s effect, which may help researchers improve modeling to better understand climate change.

“Water vapor in the stratosphere increases in tandem with increases in the Earth‘s surface temperature,” said coauthor Sean Davis, a scientist with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder, who works at the NOAA Earth System Research Laboratory. “Because water vapor is a greenhouse gas, this generates additional warming. We show that this feedback loop could be about 10% of the climate warming from all greenhouse gases.”

The new study, published online on September 30 in the prestigious journal Proceedings of the National Academy of Sciences, quantifies the magnitude of the stratospheric water vapor feedback for the first time, making use of satellite observations and a climate model.

“While it‘s not really surprising that this process is going on, we were surprised at how important the process is for our climate system,” said Andrew Dessler, an atmospheric sciences professor at Texas A&M University who was lead author of the paper. Dessler was a CIRES Visiting Fellow this year, working with Davis and other colleagues on this paper.

For well over 100 years it has been known that increased emissions of greenhouse gases such as carbon dioxide will warm the planet. As the lowest layer of the atmosphere, called the troposphere (surface to ~7 miles), is warmed, the air becomes more humid because warmer air holds more water vapor. This “tropospheric water vapor feedback” approximately doubles the initial warming caused by carbon dioxide.

The new study shows that in addition to the well-understood tropospheric water vapor feedback on climate change, there is also a significant amplifying feedback associated with water vapor in the stratosphere, the layer of the atmosphere above the troposphere that extends to ~30 miles above Earth‘s surface. This “stratospheric water vapor feedback,” although hypothesized by previous studies, has remained elusive to quantification.

The new results suggest that the stratospheric water vapor feedback may be an important component of our climate system. The researchers estimated that at a minimum this feedback adds another ~5-10% to the climate warming from the addition of greenhouse gases, and is possibly substantially more than this amount.

Most climate models contain a representation of stratospheric water vapor, so this feedback is already operating in the models to some extent. Thus, this new finding does not necessarily mean that models have underestimated future global warming. However, since the importance of this feedback has not been previously recognized, it is possible that the stratospheric water vapor feedback may help to explain some of the spread among future projections of climate change from different models. Indeed, of the ~20 models participating in the 5th Assessment report of the Intergovernmental Panel on Climate Change (IPCC), the authors found substantial differences among the models‘ future simulation of stratospheric water vapor.

Though the study has moved understanding an important step forward, many questions remain about the role of stratospheric water vapor in climate.

“The stratospheric water vapor feedback effect could be even larger than the 5-10% we found in our study,” said Davis. “Our analysis suggests that the pathways for water vapor to reach the stratosphere are not completely understood, so we view our numbers as a minimum estimate of the effect of this feedback.”

The authors of the study are Andrew Dessler (lead author) and Tao Wang (Texas A&M University); Mark Schoeberl (Science and Technology Corporation); Sean Davis (CIRES and NOAA-ESRL); and Karen Rosenlof (NOAA-ESRL).

CIRES is a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado Boulder.

More from Texas A&M:



Texas A&M University:

  • Keith Randall, News & Information Services, 979-845-4644,
  • Andrew Dessler, 979-862-1427

NOAA, CIRES, international scientists expect improvement in upcoming years

For nearly 50 years, scientists with NOAA have launched high-altitude balloons from the South Pole, to understand why a hole was forming in the protective ozone layer high in the atmosphere. Now, organizations around the world track the infamous ozone hole through these ballon-sondes, satellite measurements and ground instruments.

This year, the ozone hole was a little smaller than in years past, those measurements showed, and ozone levels in a critical region of the atmosphere did not drop as low.

“We cannot say that this represents recovery, but it is certainly good news to see this year on the higher side of the average ozone range,” said NOAA’s Bryan Johnson, with the Earth System Research Laboratory (ESRL) in Boulder, Colo.

Johnson works with colleagues at NOAA and the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder to track and understand trends in seasonal ozone from measurements made by a two-person NOAA crew at South Pole Station. Earth’s ozone layer shields life on the planet’s surface from ultraviolet radiation that can cause skin cancer and damage plants.

The Antarctic ozone hole began making a yearly appearance in the early 1980s, caused by chlorine released from man-made chemicals called chlorofluorocarbons, or CFCs. Under the the Montreal Protocol of 1987 and its later amendments, countries agreed to phase out most ozone-depleting substances, which were used in fire extinguishers and as other foams, sprays, as solvents, refrigerants and in other industries. According to NOAA global observations, chlorine levels at the poles reached a maximum at the beginning of this century and are now on the decline.

“It takes the atmosphere a while to break down these long-lived chemicals, and some can remain in the atmosphere for about 100 years,” said NOAA ESRL atmospheric scientist Steve Montzka, who is also a CIRES Fellow.

When conditions are right—as they are in the Antarctic spring—chlorine from ozone-depleting gases can rapidly break apart ozone molecules, reducing ozone over Antarctica by one half in just a couple of weeks. The World Meteorological Organization reports that this year’s ozone hole stretched about 8 million square miles (21 million square kilometers) in late September, about the size of the United States, Canada and Mexico combined. For comparison, the Antarctic ozone hole stretched to more than 10 million square miles in the record year of 2006.

Of particular interest is the region between 7 and 12 miles altitude (12-20 kilometers). There, ozone levels are more strongly influenced by man-made ozone-depleting chemicals than by natural variations in meteorology. This year, ozone levels in this region of the atmosphere only dropped to about 25 Dobson Units (DUs) in late September; in previous years, they plummeted to less than 10 DUs.

In a sign of the effectiveness of the Montreal Protocol, the ozone hole over Antarctica is likely to show signs of recovery within the next decade. NOAA and CIRES scientists will continue their long-term atmospheric measurements of ozone and ozone-depleting gases not only to capture evidence of recovery, though. Some chemicals used as substitutes for ozone-depleting gases are potent greenhouse gases, too, and pose a potentially significant climate threat.

“The need for observations will remain paramount,” said Jim Butler, director of the Global Monitoring Division of NOAA’s ESRL.  

CIRES is a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado Boulder.

Science teams from NASA and the National Oceanic and Atmospheric Administration (NOAA) have been monitoring the ozone layer from the ground and with a variety of instruments on satellites and balloons since the 1970s. These ozone instruments capture different aspects of ozone depletion. The independent analyses ensure that the international community understands the trends in this critical part of Earth's atmosphere. The resulting views of the ozone hole have differences in the computation of the size of the ozone hole, its depth, and record dates. More from NOAA here; and from NASA here.

Download the photos: [ 01 ] [ 02 ] [ 03 ]