Posts tagged NOAA
The Earth’s climate zones are shifting at an accelerating pace, says a new study led by a scientist at the CU’s Cooperative Institute for Research in Environmental Sciences.
The acceleration of change means that the species inhabiting each zone have less time to adapt to the climatic changes, said lead author Irina Mahlstein, a CIRES scientist who works at NOAA’s Earth System Research Laboratory in Boulder, Colo. “The warmer the climate gets, the faster the climate zones are shifting. This could make it harder for plants and animals to adjust.”
The study is the first to look at the accelerating pace of the shifting of climate zones, which are areas of the Earth defined by annual and seasonal cycles of temperature and precipitation, as well as temperature and precipitation thresholds of plant species. Over 30 different climate zones are found on Earth; examples include the equatorial monsoonal zone, the polar tundra zone and cold arid desert zone.
“A shift in the climate zone is probably a better measure of ‘reality’ for living systems, more so than changing temperature by a degree or precipitation by a centimeter,” said Mahlstein.
The scientists used climate model simulations and a well-known ecosystem classification scheme to look at the shifts between climate zones over a two-century period, 1900 to 2098. The team found that for an initial 3.6 degrees Fahrenheit of warming, about 5 percent of Earth’s land area shifts to a new climate zone.
The models show that the pace of change quickens for the next 3.6 F of warming as an additional 10 percent of the land area shifts to a new climate zone. The paper was published online in the journal Nature Climate Change on April 21.
Certain regions of the globe, such as northern middle and high latitudes, will undergo more changes than other regions, such as the tropics, the scientists found. In the tropics, mountainous regions will experience bigger changes than low-altitude areas.
In the coming century, the findings suggest that frost climates — the coldest climate zone of the planet — will largely decrease. In general, dry regions in different areas of the globe will increase, and a large fraction of land area will change from cool summers to hot summers, according to the study.
The scientists also investigated whether temperature or precipitation had a greater impact on how much of the land area changed zones. “We found that temperature is the main factor, at least through the end of this century,” said Mahlstein.
John Daniel at the NOAA Earth System Research Laboratory and Susan Solomon at the Massachusetts Institute of Technology co-authored the study.
-CU press release
A team led by the University of Colorado Boulder looking for clues about why Earth did not warm as much as scientists expected between 2000 and 2010 now thinks the culprits are hiding in plain sight — dozens of volcanoes spewing sulfur dioxide.
The study results essentially exonerate Asia, including India and China, two countries that are estimated to have increased their industrial sulfur dioxide emissions by about 60 percent from 2000 to 2010 through coal burning, said lead study author Ryan Neely, who led the research as part of his CU-Boulder doctoral thesis. Small amounts of sulfur dioxide emissions from Earth’s surface eventually rise 12 to 20 miles into the stratospheric aerosol layer of the atmosphere, where chemical reactions create sulfuric acid and water particles that reflect sunlight back to space, cooling the planet.
Neely said previous observations suggest that increases in stratospheric aerosols since 2000 have counterbalanced as much as 25 percent of the warming scientists blame on human greenhouse gas emissions. “This new study indicates it is emissions from small to moderate volcanoes that have been slowing the warming of the planet,” said Neely, a researcher at the Cooperative Institute for Research in Environmental Sciences, a joint venture of CU-Boulder and the National Oceanic and Atmospheric Administration.
A paper on the subject was published online in Geophysical Research Letters, a publication of the American Geophysical Union. Co-authors include Professors Brian Toon and Jeffrey Thayer from CU-Boulder; Susan Solomon, a former NOAA scientist now at the Massachusetts Institute of Technology; Jean Paul Vernier from NASA’s Langley Research Center in Hampton, Va.; Catherine Alvarez, Karen Rosenlof and John Daniel from NOAA; and Jason English, Michael Mills and Charles Bardeen from the National Center for Atmospheric Research in Boulder.
The new project was undertaken in part to resolve conflicting results of two recent studies on the origins of the sulfur dioxide in the stratosphere, including a 2009 study led by the late David Hoffman of NOAA indicating aerosol increases in the stratosphere may have come from rising emissions of sulfur dioxide from India and China. In contrast, a 2011 study led by Vernier — who also provided essential observation data for the new GRL study — showed moderate volcanic eruptions play a role in increasing particulates in the stratosphere, Neely said.
The new GRL study also builds on a 2011 study led by Solomon showing stratospheric aerosols offset about a quarter of the greenhouse effect warming on Earth during the past decade, said Neely, also a postdoctoral fellow in NCAR’s Advanced Study Program.
The new study relies on long-term measurements of changes in the stratospheric aerosol layer’s “optical depth,” which is a measure of transparency, said Neely. Since 2000, the optical depth in the stratospheric aerosol layer has increased by about 4 to 7 percent, meaning it is slightly more opaque now than in previous years.
“The biggest implication here is that scientists need to pay more attention to small and moderate volcanic eruptions when trying to understand changes in Earth’s climate,” said Toon of CU-Boulder’s Department of Atmospheric and Oceanic Sciences. “But overall these eruptions are not going to counter the greenhouse effect. Emissions of volcanic gases go up and down, helping to cool or heat the planet, while greenhouse gas emissions from human activity just continue to go up.”
The key to the new results was the combined use of two sophisticated computer models, including the Whole Atmosphere Community Climate Model, or WACCM, Version 3, developed by NCAR and which is widely used around the world by scientists to study the atmosphere. The team coupled WACCM with a second model, the Community Aerosol and Radiation Model for Atmosphere, or CARMA, which allows researchers to calculate properties of specific aerosols and which has been under development by a team led by Toon for the past several decades.
Neely said the team used the Janus supercomputer on campus to conduct seven computer “runs,” each simulating 10 years of atmospheric activity tied to both coal-burning activities in Asia and to emissions by volcanoes around the world. Each run took about a week of computer time using 192 processors, allowing the team to separate coal-burning pollution in Asia from aerosol contributions from moderate, global volcanic eruptions. The project would have taken a single computer processor roughly 25 years to complete, said Neely.
The scientists said 10-year climate data sets like the one gathered for the new study are not long enough to determine climate change trends. “This paper addresses a question of immediate relevance to our understanding of the human impact on climate,” said Neely. “It should interest those examining the sources of decadal climate variability, the global impact of local pollution and the role of volcanoes.”
While small and moderate volcanoes mask some of the human-caused warming of the planet, larger volcanoes can have a much bigger effect, said Toon. When Mount Pinatubo in the Philippines erupted in 1991, it emitted millions of tons of sulfur dioxide into the atmosphere that cooled the Earth slightly for the next several years.
The research for the new study was funded in part through a NOAA/ ESRL-CIRES Graduate Fellowship to Neely. The National Science Foundation and NASA also provided funding for the research project. The Janus supercomputer is supported by NSF and CU-Boulder and is a joint effort of CU-Boulder, CU Denver and NCAR.
Analysis of 90 years of observational data has revealed that summer climates in regions across the globe are changing — mostly, but not always, warming –according to a new study led by a scientist from the Cooperative Institute for Research in Environmental Sciences headquartered at the University of Colorado Boulder.
“It is the first time that we show on a local scale that there are significant changes in summer temperatures,” said lead author CIRES scientist Irina Mahlstein. “This result shows us that we are experiencing a new summer climate regime in some regions.”
The technique, which reveals location-by-location temperature changes rather than global averages, could yield valuable insights into changes in ecosystems on a regional scale. Because the methodology relies on detecting temperatures outside the expected norm, it is more relevant to understand changes to the animal and plant life of a particular region, which scientists would expect to show sensitivity to changes that lie outside of normal variability.
“If the summers are actually significantly different from the way that they used to be, it could affect ecosystems,” said Mahlstein, who works in the Chemical Sciences Division of the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory.
To identify potential temperature changes, the team used climate observations recorded from 1920 to 2010 from around the globe. The scientists termed the 30-year interval from 1920 to 1949 the “base period,” and then compared the base period to other 30-year test intervals starting every 10 years since 1930.
The comparison used statistics to assess whether the test interval differed from the base period beyond what would be expected due to yearly temperature variability for that geographical area.
Their analysis found that some changes began to appear as early as the 1960s, and the observed changes were more prevalent in tropical areas. In these regions, temperatures varied little throughout the years, so the scientists could more easily detect any changes that did occur, Mahlstein said.
The scientists found significant summer temperature changes in 40 percent of tropical areas and 20 percent of higher-latitude areas. In the majority of cases, the researchers observed warming summer temperatures, but in some cases they observed cooling summer temperatures.
“This study has applied a new approach to the question, ‘Has the temperature changed in local areas?’ ” Mahlstein said. The study is in press in the journal Geophysical Research Letters, a publication of the American Geophysical Union.
The study’s findings are consistent with other approaches used to answer the same question, such as modeling and analysis of trends, Mahlstein said. But this technique uses only observed data to come to the same result. “Looking at the graphs of our results, you can visibly see how things are changing,” she said.
In particular the scientists were able to look at the earlier time periods, note the temperature extremes, and observe that those values became more frequent in the later time periods. “You see how the extreme events of the past have become a normal event,” Mahlstein said.
The scientists used 90 years of data for their study, a little more than the average lifespan of a human being. So if inhabitants of those areas believe that summers have changed since they were younger, they can be confident it is not a figment of their imagination.
“We can actually say that these changes have happened in the lifetime of a person,” Mahlstein said.
Co-authors on the study were Gabriele Hegerl from the University of Edinburgh in Scotland and Susan Solomon from Massachusetts Institute of Technology.
CIRES is a joint institute of CU-Boulder and NOAA.
NOAA selects CU-Boulder to
continue joint leadership of CIRES
The National Oceanic and Atmospheric Administration has selected the University of Colorado Boulder to continue a federal/academic partnership that extends NOAA’s ability to study climate change, improve weather models and better predict how solar storms can disrupt communication and navigation technologies.
The selection means that NOAA will continue funding the Cooperative Institute for Research in Environmental Sciences, or CIRES, for at least five years and up to 10 more years. CIRES was established at CU-Boulder in 1967.
The amount of the award is contingent on the availability of funding in the federal budget, but NOAA anticipates that up to $32 million may be available annually. Total NOAA funding is variable from year to year and is based on the number of projects the university proposes and NOAA approves.
Following a competitive process, NOAA selected CU-Boulder to administer the CIRES partnership which leverages university resources to expand understanding of the “Earth system” — the interrelationships among the atmosphere, oceans, land, living things and the sun’s energy.
“Improving our understanding of the Earth system is critically important as the build-up of greenhouse gases in the atmosphere is forcing changes in all of its processes,” said Robert Detrick, assistant administrator of the NOAA Office of Oceanic and Atmospheric Research and chairman of the NOAA Research Council. “The University of Colorado has been an excellent partner to NOAA in pursuing this mission.”
NOAA’s first cooperative institute, CIRES is marking its 45th anniversary this year and is now one of 18 NOAA cooperative institutes nationwide. NOAA competitively funds cooperative institutes at universities with strong research programs relevant to NOAA’s mission. These institutes provide resources and opportunities that extend beyond the agency’s own research capacity.
“Partnership in environmental research with the NOAA Boulder laboratories is the keystone of CIRES research,” said CIRES Interim Director William Lewis Jr. “We have great ambitions in joint research with NOAA over the next five years.”
The partnership allows researchers at CU-Boulder to receive support for research projects that may involve NOAA scientists, primarily at the Earth System Research Laboratory in Boulder as well as other NOAA cooperative institutes.
The CIRES partnership will focus on nine research themes:
- Air quality in a changing environment
- Climate forcing feedbacks and analysis
- Earth systems dynamics, variability and change
- Management and exploitation of geophysical data
- Regional science and applications
- Scientific outreach and education
- Space weather understanding and predictability
- Stratospheric processes and trends
- Systems and prediction models development
“With pressing issues like air quality, climate change and space weather now at the forefront globally, the University of Colorado Boulder is eager to continue this crucial partnership with NOAA,” said CU-Boulder Vice Chancellor for Research Stein Sture. “CIRES is known around the world for advancing our understanding of the complex Earth system and as a premier institution in educating the next generation of environmental scientists.”
NOAA supports cooperative institutes to conduct research, education, training and outreach aligned with its mission. Cooperative institutes also promote the involvement of students and postdoctoral scientists in NOAA-funded research. This unique setting provides NOAA the benefit of working with the complementary capabilities of a research institution that contribute to NOAA-related sciences ranging from satellite climatology and fisheries biology to atmospheric chemistry and coastal ecology.
CU-NOAA study provides first direct evidence of
heat-trapping effects of wildfire smoke particles
When the Fourmile Canyon Fire erupted west of Boulder in 2010, smoke from the wildfire poured into parts of the city including a site housing scientists from the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences and the National Oceanic and Atmospheric Administration.
Within 24 hours, a few researchers at the David Skaggs Research Center had opened up a particle sampling port on the roof of the building and started pulling in smoky air for analysis by two custom instruments inside. They became the first scientists to directly measure and quantify some unique heat-trapping effects of wildfire smoke particles.
“For the first time we were able to measure these warming effects minute-by-minute as the fire progressed,” said CIRES scientist Dan Lack, lead author of the study published today in the Proceedings of the National Academy of Sciences.
The researchers also were able to record a phenomenon called the “lensing effect,” in which oils from the fire coat the soot particles and create a lens that focuses more light onto the particles. This can change the “radiative balance” in an area, sometimes leading to greater warming of the air and cooling of the surface.
While scientists had previously predicted such an effect and demonstrated it in laboratory experiments, the Boulder researchers were one of the first to directly measure the effect during an actual wildfire. Lack and his colleagues found that lensing increased the warming effect of soot by 50 to 70 percent.
“When the fire erupted on Labor Day, so many researchers came in to work to turn on instruments and start sampling that we practically had traffic jams on the road into the lab,” Lack said. “I think we all realized that although this was an unfortunate event, it might be the best opportunity to collect some unique data. It turned out to be the best dataset, perfectly suited to the new instrument we had developed.”
The instrument called a spectrophotometer can capture exquisite detail about all particles in the air, including characteristics that might affect the smoke particles’ tendency to absorb sunlight and warm their surroundings. While researchers know that overall, wildfire smoke can cause this lensing effect, the details have been difficult to quantify, in part because of sparse observations of particles from real-world fires.
Once the researchers began studying the data they collected during the fire, it became obvious that the soot from the wildfire was different in several key ways from soot produced by other sources — diesel engines, for example.
“When vegetation burns, it is not as efficient as a diesel engine, and that means some of the burning vegetation ends up as oils,” Lack said. In the smoke plume, the oils coated the soot particles and that microscopic sheen acted like a magnifying glass, focusing more light onto the soot particles and magnifying the warming of the surrounding air.
The researchers also discovered that the oils coating the soot were brown, and that dark coloration allowed further absorption of light, and therefore further warming the atmosphere around the smoke plume.
The additional warming effects mean greater heating of the atmosphere enveloped in dark smoke from a wildfire, and understanding that heating effect is important for understanding climate change, Lack said. The extra heating also can affect cloud formation, air turbulence, winds and even rainfall.
The discovery was made possible by state-of-the-art instruments developed by CIRES, NOAA and other scientists, Lack said. The instruments can capture fine-scale details about particles sent airborne by the fire, including their composition, shape, size, color and ability to absorb and reflect sunlight of various wavelengths.
“With such well-directed measurements, we can look at the warming effects of soot, the magnifying coating and the brown oils and see a much clearer, yet still smoky picture of the effect of forest fires on climate,” Lack said.
According to Boulder County fire and Police dispatch there was a lighting fire up on Lee Hill but heavy rains put it out. All Fire and police went into emergency Flash Flood monitoring for all creeks around Boulder. As of this writing 3:47 nothing has occurred.
Rain came down sideways in Noth boulder . The BC1 rain gauge measure 5 inches per hour for 10 minutes. NOAA has issued Severe weather alert see below. Boulder OEM did not open nor send out an alert. Information was gather first by Boulder Channel 1 News.
Flash Flood Warning
FLASH FLOOD WARNING
BULLETIN – EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
327 PM MDT MON JUL 30 2012
THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A
* FLASH FLOOD WARNING FOR…
CENTRAL BOULDER COUNTY IN NORTHEAST COLORADO
* UNTIL 530 PM MDT
* AT 324 PM MDT…NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN FROM A THUNDERSTORM 3 MILES SOUTHWEST OF GOLD
HILL…OR 34 MILES NORTHWEST OF DENVER. THIS STORM WAS MOVING EAST
AT 15 MPH.
* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
WALLSTREET…SUNSHINE…SUMMERVILLE…SALINA…CRISMAN AND GOLD
RAIN GAUGES IN THE FOUR MILE BURN AREA HAVE ALREADY RECORDED UP TO
0.70 INCH OF RAIN SINCE 3:00 PM MDT.
A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE. TURN AROUND…DO NOT DROWN.
HEAVY RAINFALL WILL CAUSE FLASH FLOODING OF CREEKS…STREAMS…AND
DITCHES IN THE FOURMILE BURN AREA. SOME DRAINAGE BASINS AFFECTED BY
EXCESSIVE RUNOFF INCLUDE FOURMILE CREEK…GOLD RUN…AND FOURMILE
CANYON CREEK. WATER WILL BE FLOWING DOWN ROADWAYS. ROCK SLIDES OR
DEBRIS FLOWS CAN ALSO BE EXPECTED.
Fire fighters are preparing defense lines near Shanahan Ridge subdivision as the Flag Staff Fire pushes south. Once the winds pick up in the next hour the air defense will grind to a halt. Fire fighter s will then start a back fire and run fire hoes as crews will put their lives on the line.
But this could back fire and drive fire fighters out of Shanahan ridge. Fire could destroy that entire area in the next three days. Below , weather report from NOAA does not bode well for Boulder. We are in a Red Flag warning high fire state. It would be prudent to pack your entire home if you live in Shanahan ridge area. You could lose it all.
...RED FLAG WARNING IN EFFECT FOR THE FRONT RANGE FOOTHILLS AND
SOUTH PARK IN PARK COUNTY FOR SOME DRY THUNDERSTORMS PRODUCING
WIND GUSTS TO 45 MPH FROM NOON TO 8 PM MDT TODAY…
THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
.DAY ONE…TODAY AND TONIGHT
INCREASING CLOUDS OVER COLORADO AT MIDDAY WILL SPAWN SCATTERED
THUNDERSTORMS IN THE MOUNTAINS AND OVER THE FRONT RANGE FOOTHILLS
THIS AFTERNOON. SOME OF THESE STORMS WILL PRODUCE STRONG AND GUSTY
WINDS AND FREQUENT CLOUD-TO-GROUND LIGHTNING. WHILE OTHER STORMS
MAY DEPOSIT UP TO A QUARTER INCH OF RAIN IN LESS THAN 30 MINUTES.
THUNDERSTORMS ARE THEN EXPECTED TO MOVE OUT OVER THE NEARBY PLAINS
WHERE THEY MAY PRODUCE SIMILAR WIND GUSTS AND DANGEROUS LIGHTNING.
HOWEVER…STORM COVERAGE IS NOT EXPECTED TO BE AS GREAT AS THAT IN
THE HIGH COUNTRY. MOST OF THIS STORM ACTIVITY SHOULD DIMINISH
LATER THIS EVENING.
OTHERWISE..SLIGHTLY COOLER TEMPERATURES AND HIGHER HUMIDITIES ARE
ON TAP FOR THE OUTLOOK AREA TODAY. A WEAK COLD FRONT BACKING INTO
NORTHEAST COLORADO EARLY THIS AFTERNOON WILL BE RESPONSIBLE FOR
SOME OF THE COOLING ON THE PLAINS.
Five Day Weather Forecast FOR BOULDER
This Afternoon: Scattered showers and thunderstorms, mainly after 3pm. Mostly cloudy, with a high near 94. Southwest wind 9 to 13 mph becoming east southeast. Winds could gust as high as 17 mph. Chance of precipitation is 40%.
Tonight: Isolated showers and thunderstorms before midnight. Mostly cloudy, with a low around 65. South southeast wind 6 to 14 mph becoming west northwest. Winds could gust as high as 20 mph. Chance of precipitation is 10%.
Thursday: A 10 percent chance of showers and thunderstorms after noon. Mostly sunny and hot, with a high near 97. West wind between 10 and 13 mph becoming light. Winds could gust as high as 17 mph.
Thursday Night: A 10 percent chance of showers and thunderstorms before midnight. Partly cloudy, with a low around 63. West wind between 5 and 10 mph, with gusts as high as 16 mph.
Friday: A 10 percent chance of showers and thunderstorms after noon. Mostly sunny and hot, with a high near 97. West wind around 5 mph becoming calm.
Friday Night: A 10 percent chance of showers and thunderstorms before midnight. Partly cloudy, with a low around 65.
Gasoline worse than diesel when it
comes to some types of air pollution
The exhaust fumes from gasoline vehicles contribute more to the production of a specific type of air pollution — secondary organic aerosols — than those from diesel vehicles, according to a new study by scientists from the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences, or CIRES, NOAA’s Earth System Research Laboratory and other colleagues.
“The surprising result we found was that it wasn’t diesel engines that were contributing the most to the organic aerosols in L.A.,” said CIRES research scientist Roya Bahreini who led the study and also works at the National Oceanic and Atmospheric Administration’s ESRL. “This was contrary to what the scientific community expected.”
SOAs are tiny particles that are formed in air and make up typically 40-60 percent of the aerosol mass in urban environments. This is important because fine-particle pollution can cause human health effects, such as heart or respiratory problems.
Due to the harmful nature of these particles and the fact that they can also impact the climate and can reduce visibility, scientists want to understand how they form, Bahreini said. Researchers had already established that SOAs could be formed from gases released by gasoline engines, diesel engines and natural sources — biogenic agents from plants and trees — but they had not determined which of these sources were the most important, she said.
“We needed to do the study in a location where we could separate the contribution from vehicles from that of natural emissions from vegetation,” Bahreini said.
Los Angeles proved to be an ideal location. Flanked by an ocean on one side and by mountains to the north and the east, it is, in terms of air circulation, relatively isolated, Bahreini said. At this location, the scientists made three weekday and three weekend flights with the NOAA P3 research aircraft, which hosted an arsenal of instruments designed to measure different aspects of air pollution.
“Each instrument tells a story about one piece of the puzzle,” Bahreini said. “Where do the particles come from? How are they different from weekday to weekend, and are the sources of vehicle emissions different from weekday to weekend?”
From their measurements, the scientists were able to confirm, as expected, that diesel trucks were used less during weekends, while the use of gasoline vehicles remained nearly constant throughout the week. The team then expected that the weekend levels of SOAs would take a dive from their weekday levels, Bahreini said.
But that was not what they found.
Instead, the levels of SOA particles remained relatively unchanged from their weekday levels. Because the scientists knew that the only two sources for SOA production in this location were gasoline and diesel fumes, the study’s result pointed directly to gasoline as the key source.
“The contribution of diesel to SOA is almost negligible,” Bahreini said. “Even being conservative, we could deduce from our results that the maximum upper limit of contribution to SOA would be 20 percent.”
That leaves gasoline contributing the other 80 percent or more of the SOA, Bahreini said. The finding was published online March 1 in Geophysical Research Letters. “While diesel engines emit other pollutants such as soot and nitrogen oxides, for organic aerosol pollution they are not the primary culprit,” Bahreini said.
If the scientists were to apply their findings from the L.A. study to the rest of the world, a decrease in the emission of organic species from gasoline engines may significantly reduce SOA concentrations on a global scale as well. This suggests future research aimed at understanding ways to reduce gasoline emissions would be valuable.
The study was funded by NOAA’s Climate Change and Air Quality Programs, the California Air Resources Board and the National Science Foundation.
CIRES coauthors on the team include Joost de Gouw, Carsten Warneke, Harald Stark, William Dube, Jessica Gilman, Katherine Hall, John Holloway, Anne Perring, Joshua Schwarz, Ryan Spackman and Nicholas Wagner.
STUDY INDICATES HAIL MAY DISAPPEAR
FROM COLORADO’S FRONT RANGE BY 2070
Summertime hail could all but disappear from the eastern flank of Colorado’s Rocky Mountains by 2070, says a new study by the National Oceanic and Atmospheric Administration, the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences and the National Center for Atmospheric Research.
Less hail damage could be good news for gardeners and farmers, said lead author Kelly Mahoney, a research scientist at CIRES, but a shift from hail to rain can also mean more runoff, which could raise the risk of flash floods. “In this region of elevated terrain, hail may lessen the risk of flooding because it takes awhile to melt,” Mahoney said. “Decision makers may not want to count on that in the future.”
For the new study, published this week in the journal Nature Climate Change, Mahoney and her colleagues used “downscaling” techniques to try to understand how climate change might affect hail-producing weather patterns across Colorado.
The research focused on storms involving pea-sized and smaller hailstones on Colorado’s Front Range, a region that stretches from the foothill communities of Colorado Springs, Denver and Fort Collins up to the Continental Divide. Colorado’s most damaging hailstorms tend to occur further east and involve larger hailstones not examined in this study.
In the summer in Colorado’s Front Range above about 7,500 feet, precipitation commonly falls as hail. Decision makers concerned about the safety of mountain dams and flood risk have been interested in how climate change may affect the amount and nature of precipitation in the region.
Mahoney and her colleagues began exploring that question with results from two climate models, which assumed that levels of climate-warming greenhouse gases will continue to increase in the future, from about 390 parts per million in the atmosphere today to about 620 parts per million in 2070.
But the weather processes that form hail, like thunderstorms, occur on much smaller scales than can be reproduced by global climate models. So the team “downscaled” the global model results twice: first to regional-scale models that can take regional topography and other details into account, then again to weather-scale models that can resolve individual storms and even the cloud processes that create hail. The regional-scale topography step was completed as part of NCAR’s North American Regional Climate Change Assessment Program.
Finally, the team compared the hailstorms of the future, from 2041 to 2070, to those of the past, from 1971 to 2000, as captured by the same sets of downscaled models. Results were similar in experiments with both climate models.
“We found a near elimination of hail at the surface,” Mahoney said.
In the future, increasingly intense storms may actually produce more hail inside clouds, the team found. However, because those relatively small hailstones fall through a warmer atmosphere, they melt quickly, falling as rain at the surface or evaporating back into the atmosphere. In some regions, simulated hail fell through an additional 1,500 feet of above-freezing air in the future as compared with the past.
The research team also found evidence that precipitation events over Colorado become more extreme in the future, while changes in hail may depend on the size of the hailstones — results that will be explored in more detail in ongoing work.
Mahoney’s postdoctoral research was supported by the Postdocs Applying Climate Expertise, or PACE, program administered by the University Corporation for Atmospheric Research and funded by CIRES Western Water Assessment, NOAA and the U.S. Bureau of Reclamation. PACE connects young climate scientists with real-world problems such as those faced by water resource managers.
Co-authors of the new paper include James Scott and Joseph Barsugli of CIRES and NOAA, Michael Alexander of the NOAA Earth System Research Laboratory and Gregory Thompson of NCAR.
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Cigarette smoking, burning forests and even cooking fires all release a chemical compound not previously known to exist in significant quantities in smoke and which may have potential human health impacts, says a new study involving the National Oceanic and Atmospheric Administration and the University of Colorado Boulder.
The study was conducted by scientists at the Cooperative Institute for Research in Environmental Sciences, or CIRES — a joint institute of CU-Boulder and NOAA — along with researchers from NOAA’s Earth System Research Laboratory.
The molecule, isocyanic acid, is similar to methyl isocyanate, the gas that leaked from a pesticide plant in Bhopal, India, in 1984 killing more than 3,000 people within weeks. “The molecule has hardly been measured before — certainly not in the atmosphere,” said CIRES Fellow Joost de Gouw, coauthor of the new paper published May 16 in the Proceedings of the National Academy of Sciences. “So it was a complete surprise to find it in such large quantities.”
De Gouw and his colleagues were first able to detect isocyanic acid when they developed and tested a new instrument, a mass spectrometer designed to measure gaseous acids in the air. In the laboratory, they found biomass burning — the burning of trees or plant material — produced levels of the molecule approaching 600 parts per billion by volume, or ppbv.
“There is this molecule in smoke that we can now measure and it is there in significant quantities,” de Gouw said. “There are good reasons to believe that it can have significant health impacts.”
In the human body, isocyanic acid dissolves to form charged cyanate molecules, and the researchers found that the acid was very soluble at the pH level of human blood. This means it could potentially enter the bloodstream, said de Gouw. When the exposure levels of isocyanic acid are greater than 1 ppbv, the charged cyanate molecules are expected to be present at levels that can contribute to a variety of human health problems like cardiovascular disease, cataracts and rheumatoid arthritis.
Once the researchers discovered that fires produced the gas at the U.S. Forest Service Fire Sciences Laboratory in Missoula, Mont., they then took their instruments out of the lab to see whether smoke in a “real” environment also gave off this chemical. “We had a new tool to look around us and we just explored,” de Gouw said. “It was basically our chemical curiosity at work.”
Previous studies have shown that burning coal produces isocyanic acid, and the CIRES researchers have discovered the chemical also is present in tobacco smoke and smoke from the combustion of other plant materials. In rural areas of developing countries where biofuels are used for cooking and heating, exposure levels of the acid could be harmful, according to the research team.
But does a real fire, as opposed to a lab fire, give off the acid? The team didn’t have to wait long to find out. Starting on Labor Day 2010, the Fourmile Canyon wildfire raged in the foothills above Boulder, Colo., burning more than 6,000 acres and destroying 169 homes. Scientists at the NOAA Earth System Research Laboratory in Boulder wasted no time in learning what they could about the event.
The team’s spectrometer detected levels of the acid up to 200 pptv in the air at the site, which was downwind from the fire. “Boulder has a world-class atmospheric chemistry building and only once in its lifetime is it going to have a full-on hit from a wildfire,” de Gouw said. “So just about everyone in that building turned on their instruments.”
One possibility was that the acid would only be prevalent in the immediate vicinity of a fire, de Gouw said. “But that didn’t happen,” he said. “We were miles away and it was still there.”
The researchers didn’t constrain their measurements to wildfires. They also used their equipment to find the levels of isocyanic acid in the urban environment of Los Angeles. “In LA we find even when there are no fires there is a little of this acid,” de Gouw said. “So smoke may not be the only source of it in the atmosphere.”
Since more isocyanic acid was measured in the atmosphere during the day, sunlight could be sparking the chemical reactions that make it, de Gouw said. Another potential source in urban air could be emissions from diesel engines outfitted with the latest generation of pollution control equipment that is now being introduced in California and Europe, he said.
“We know so little about isocyanic acid’s behavior in the atmosphere that we want to do a number of follow-up studies, “ de Gouw said. “We have some data in our paper but that is just the beginning and we need to do a lot more work.”
Other authors on the PNAS paper included Jim Roberts, Patrick Veres, Anthony Cochran, Carsten Warneke, Ian Burling, Robert Yokelson, Brian Lerner, Jessica Gilman, William Kuster and Ray Fall.
Hi 72 °F
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Thursday: Mostly sunny, with a high near 77. West wind between 4 and 7 mph becoming calm.
Thursday Night: A 10 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 47. East wind at 9 mph becoming northwest.
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