EOL

EOL Seminar Series: Britton Stephens

Oceanography among the clouds and terrestrial ecology a thousand miles from land: The power of global-scale airborne observations 
Britton Stephens
National Center for Atmospheric Research

EOL Seminar Series: Dr. Richard Anthes

Estimating observation and model error variances using multiple data sets
Dr. Richard Anthes
UCAR President Emeritus

The climate secrets of southern clouds

BOULDER, Colo. — This month, an international team of scientists will head to the remote Southern Ocean for six weeks to tackle one of the region's many persistent mysteries: its clouds.What they discover will be used to improve climate models, which routinely underestimate the amount of solar radiation reflected back into space by clouds in the region. Accurately simulating the amount of radiation that is absorbed or reflected on Earth is key to calculating how much the globe is warming.The field campaign, called the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study, or SOCRATES, could also help scientists understand the very nature of how clouds interact with aerosols — particles suspended in the atmosphere that can be from either natural or human-made sources. Aerosols can spur cloud formation, change cloud structure, and affect precipitation, all of which affect the amount of solar radiation that is reflected.During the mission, which will run from mid-January through February, the scientists will collect data from a bevy of advanced instruments packed onboard an aircraft and a ship, both of which are specially designed for scientific missions."SOCRATES will allow for some of the best observations of clouds, aerosols, radiation, and precipitation that have ever been collected over the Southern Ocean," said Greg McFarquhar, a principal investigator and the director of the University of Oklahoma Cooperative Institute for Mesoscale Meteorological Studies (CIMMS). "These data will provide us with critical insight into the physics of cloud formation in the region, information we can use to improve global climate models."The U.S. portion of SOCRATES is largely funded by the National Science Foundation (NSF).“The Southern Ocean is famously remote and stormy and it's hard to imagine a worse place to do a field campaign. But a vast, stormy ocean is a great laboratory for studying clouds, and it's clear from our models that we have a lot to learn about them,” said Eric DeWeaver, program director for Climate and Large-Scale Dynamics in NSF’s Geoscience directorate."I'm excited about this campaign because I think it will answer some fundamental questions about clouds and their dependence on atmospheric conditions," DeWeaver said. "We'll be able to use this information to understand cloud behavior closer to home and how clouds are likely to adjust to changing climatic conditions."Critical observing and logistical support for SOCRATES is being provided by the Earth Observing Laboratory (EOL) at the National Center for Atmospheric Research (NCAR). Other U.S. principal investigators are based at the University of Washington.The Australian portion of SOCRATES is largely funded by the country's government through the Australian Marine National Facility, which is owned and operated by CSIRO.A supercooled mysteryMcFarquhar and his colleagues think the reason that climate models are not accurately capturing the amount of radiation reflected by clouds above the Southern Ocean is because they may not be correctly predicting the composition of the clouds. In particular, the models may not be producing enough supercooled water — droplets that stay liquid even when the temperature is below freezing.One possible explanation for the problem is the way models represent how clouds interact with aerosols, a process that affects the amount of supercooled water in a cloud. These representations were developed from atmospheric observations, largely in the Northern Hemisphere, where most of the world's population lives.But the atmosphere over the Northern Hemisphere — even over the Arctic — contains many more pollutants, including aerosols, than the atmosphere over the Southern Ocean, which is relatively pristine."We don't know how appropriate the representations of these processes are for the Southern Hemisphere," McFarquhar said. "SOCRATES will give us an opportunity to observe these cloud-aerosol interactions and see how much they differ, if at all, from those in the Northern Hemisphere."Flying through hazardous cloudsThe NSF/NCAR HIAPER Gulfstream V has been modified to serve as a flying laboratory. (©UCAR. This figure is freely available for media & nonprofit use.)For the SOCRATES field campaign, observations will be taken from the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research, or HIAPER, a highly modified Gulfstream V aircraft, and the R/V Investigator, an Australian deep-ocean research vessel."Much of what we currently know about Southern Ocean cloud, aerosol, and precipitation properties comes from satellite-based estimates, which are uncertain and have undergone few comparisons against independent data," said co-investigator Roger Marchand, a scientist at the University of Washington. "The data collected during SOCRATES will also enable us to evaluate current satellite data over the Southern Ocean, as well as potentially help in the design of better satellite-based techniques."The research aircraft will be based out of Hobart, Tasmania, and will make about 16 flights over the Southern Ocean during the course of the campaign. The many high-tech instruments on board will measure the size and distribution of cloud droplets, ice crystals, and aerosols, as well as record the temperature, winds, air pressure, and other standard atmospheric variables.The instruments include NCAR's HIAPER Cloud Radar (HCR) and High Spectral Resolution Lidar (HSRL). The wing-mounted HCR is able to "see" inside clouds and characterize the droplets within, while the HSRL can measure air molecules and aerosols. Together, the two highly advanced instruments will give scientists a more complete picture of the wide range of particles in the atmosphere above the Southern Ocean.The nature of the research — flying a plane in search of supercooled water —presents some challenges with aircraft icing."Oftentimes, the cleaner the air, the more probable large drops and severe icing conditions become," said Cory Wolff, the NCAR project manager who is overseeing aircraft operations for SOCRATES. "We have a number of precautions we're taking to mitigate that risk."First, a mission coordinator whose sole job is to monitor icing conditions will join each flight. Second, the design of the flights themselves will help the crew anticipate icing conditions before they have to fly through them. On the flight south from Tasmania, the HIAPER GV will fly high above the clouds — and the icing danger. During that leg of the flight, the scientists will collect information about the clouds below, both with onboard radar and lidar as well as with dropsondes — small instrument packages released from the aircraft.With that information, the scientists can determine whether it's safe to pilot the aircraft through the clouds on the return trip, collecting detailed information about the cloud composition.Sailing the stormiest seasThe Australian R/V Investigator will take measurements of the atmosphere and ocean during its six-week voyage. (Image courtesy CSIRO.)The measurements taken from the sky will be complemented by data collected from instruments on board the Australian R/V Investigator, including the NCAR Integrated Sounding System. The ISS gathers extensive data by using a radar wind profiler, surface meteorology sensors, and a balloon-borne radiosonde sounding system. The team will launch soundings every six hours, and sometimes more often, throughout the campaign."Observations from the ship will help us understand the background state of the atmosphere — how it's behaving," said NCAR scientist Bill Brown, who traveled to Australia in late November to prepare the ISS for the voyage.The ship will be deployed for the entire six weeks and will face its own challenges, notably the notorious roughness of the Southern Ocean, sometimes called the stormiest place on Earth."There are no land masses to break up the winds down there," Brown said. "So the ocean can be quite rough."SOCRATES investigators will also draw on measurements from another Australian ship as it travels between Tasmania and Antarctica on resupply missions, the R/V Aurora Australis, as well as observations from buoys and some land-based instruments on Macquarie Island."I am excited that we will have such a comprehensive suite of observations," McFarquhar said. "If we just had the cloud observations we wouldn’t have the appropriate context. If we just had the aerosols and measurements below the clouds, we wouldn't be able to understand the complete picture."For more about the SOCRATES campaign, visit the project website.Collaborating institutions:Australian Antarctic DivisionAustralian Bureau of MeteorologyAustralian Department of Environment and EnergyColorado State UniversityCooperative Institute for Mesoscale Meteorological StudiesCSIROKarlsruhe Institute of TechnologyMonash UniversityNational Center for Atmospheric ResearchNational Science FoundationNorthWest Research AssociatesQueensland University of TechnologyUniversity of California San DiegoUniversity of Colorado BoulderUniversity of Illinois at Urbana-ChampaignUniversity of MelbourneUniversity of OklahomaUniversity of Washington

EOL Seminar Series: Joshua Soderholm

Outcomes of the Coastal Convective Interactions Experiment and new horizons with the Australian radar network

Abstract: This seminar will present two topics from the Australian observational meteorology research space.

Capturing a detailed portrait of wind

April 28, 2017 | For two autumns in the early 1980s, researchers covered an isolated, gently sloping hill in Scotland with dozens of scientific instruments to measure the behavior of wind as it blew up and over from the nearby coast. More than three decades later, the resulting data set gathered on Askervein hill is still the benchmark for validating how well a computer model can simulate winds flowing over complex terrain.An image of the hill at Askervein. (Image courtesy of York University.)But that's about to change.The National Center for Atmospheric Research (NCAR) is partnering with colleagues in Europe and the United States on a field project in Portugal, called Perdigão, that will measure wind at an unprecedented resolution, both in time and space, as it moves through a more topographically diverse study area.The experiment aims to help scientists improve their understanding of the basic physics of wind in the boundary layer (the lowest few hundred feet of the atmosphere). The completed data set will also serve as a new, more detailed, and more complex benchmark for testing the accuracy of the next generation of wind models.Having accurate models of wind behavior in the boundary layer, where most weather occurs, is critical for a wide range of applications, from harvesting wind energy to predicting the spread of air pollution to piloting drones.'No easy feat'When scientists selected the Perdigão study area in central Portugal, they were looking for a place more complex than the single hill at Askervein but still relatively simple and easy to model.Perdigão has two nearly parallel ridgelines that stand just a couple of kilometers apart, and the wind typically hits these ridges at a perpendicular angle, either from the southwest or the northeast. Unlike the Askervein hill, which was covered largely in heather and small shrubs, the landscape at Perdigão includes both forested and agricultural lands. Such differences in terrain and land cover can have important influences on local winds.For the project, which begins its six-week "intensive operations period" on May 1, NCAR's Earth Observing Lab was tasked with outfitting 47 observational towers with instruments that will collect data on wind speed and direction, as well as temperature and humidity, from a variety of heights. The NCAR team is also in charge of networking all the instruments being used for the field campaign so they can talk to each other and to the researchers."This is the largest ground-based project we have ever taken on," said Alison Rockwell, who is managing the project for NCAR. "Networking that many towers with that many instruments — it's no easy feat."The Perdigão study area, with its nearly parallel ridges, as seen using Google Earth. (©UCAR. Courtesy NCAR Earth Observing Laboratory. This image is freely available for media & nonprofit use.) A unique look at the wind's mysteriesThe measurements taken by the instruments on the 47 towers outfitted by NCAR, along with those from five additional towers provided by project partners, will be supplemented by observations from a variety of other balloon-borne and ground-based instruments. Those include lidars, which can remotely measure the basic structure of the wind field using laser beams."One of the totally unique aspects of this experiment is the use of lidars to measure the main wind field," said NCAR scientist Steve Oncley, a contributing investigator on the project. "It frees up the instruments on the towers to measure the fine-scale turbulence close to the ground."This ability to measure the wind at multiple scales simultaneously is another reason that data gathered during Perdigão is expected to be a vast improvement over the 1980s data set. While a similar number of towers were deployed at the Askervein hill, the instruments primarily measured wind at only one height, leaving much of the structure of fine-scale turbulence occurring close to ground a mystery.One of the questions that Oncley hopes the experiment will answer in particular — which the 1980s data could not — is how wind behaves as it blows over the crest of the ridge: "When you have a strong wind, does it actually blow through the trees, down to the soil? Or does it just graze the tops of the trees as it flows over?"The answer matters for understanding how much momentum is extracted from the wind, as well as how much heat and carbon dioxide are transferred between wind and landscape.The Perdigão project is part of a larger effort to publish a digital New European Wind Atlas, supported by a European Union funding instrument called ERANET+. The Europeans are particularly interested in the detailed wind velocity data for use in wind energy development.U.S. principal investigators are Joe Fernando (University of Notre Dame), Julie Lundquist (University of Colorado, Boulder), Petra Klein (University of Oklahoma), Rebecca Barthelmie (Cornell University), Sara Pryor (Cornell University), Tina Katopodes Chow (University of California, Berkeley), Chris Hocust (U.S. Army Research Laboratory), and Laura Leo (University of Notre Dame).European Principal Investigators are Jakob Mann (Technical University of Denmark) and José Palma (University of Porto, Portugal).Data from a long-range wind scanner at the Perdigão site  Writer/contact:Laura Snider, Senior Science Writer and Public Information Officer

EOL Seminar: Marine Ice Nucleating Particles: Implications for High Latitude Aerosol-Cloud Interactions

Marine Ice Nucleating Particles: Implications for High Latitude Aerosol-Cloud Interactions

Christina S. McCluskey
Department of Atmospheric Science
Colorado State University

Opening doors to a career in geoscience

March 8, 2017 | Michael Bell, recently honored as one of America's outstanding early-career scientists, took an unconventional path to becoming a top tropical cyclone researcher.Bell said he always had an interest in meteorology but the University of Florida, where he first attended, didn't have that major. "I started as a physics major, but I realized that high energy particle physics wasn't for me." So, because he had enjoyed his comparative religion classes, he wound up as a religion major.But since he already had taken many math and physics courses, it was relatively straightforward to go back to school and pursue a second bachelor's in mathematics and meteorology at Metropolitan State College (now Metropolitan State University) in Denver. There he had a professor, Anthony Rockwood, who had worked at the National Center for Atmospheric Research and encouraged Bell to apply for a student assistantship.Michael Montgomery, Michael Bell, and Wen-Chau Lee (left to right) during the THORPEX Pacific Asian Regional Campaign in Guam in 2008. Lee was Bell's mentor at NCAR and Montgomery, of the Naval Postgraduate School, was Bell's Ph.D. adviser. (Photo courtesy Wen-Chau Lee, NCAR.)The cliché is that the rest is history, and it fits in this case. Bell was so successful as a student assistant that he would spend another decade at NCAR before leaving for academia. In December 2016, President Obama honored Bell as one of America's outstanding early-career scientists. The Office of Naval Research nominated Bell for the award in recognition of his hurricane and typhoon research, much of which was done for the Navy."This is a career highlight for me, " Bell, wrote in an email to his mentor Wen-Chau Lee, an NCAR senior scientist, shortly after being notified of the honor. "I owe you a debt of gratitude for all of the opportunities you have provided me over the years.""NCAR taught me to think critically about data quality and the assumptions that go into data," Bell, now an associate professor at Colorado State University, said in a recent interview. "The field projects (which included flying close to hurricanes) taught me the importance of careful planning and execution, so when the weather you want to study occurs, you're ready to take advantage of it."Bell's enthusiasm and desire to learn impressed the NCAR hiring team, Lee recalled. "He said, 'I want this, I think I can do it.'""I have to invest a lot of time to train a student assistant," Lee said, "so I wasn't looking for a candidate with a ton of programming experiences who would stay a year and leave. I was looking for someone who could assist me over the relatively long term, and I had a feeling that Michael could do it."During his stint at NCAR, Bell was part of at least a half-dozen field campaigns, including RAINEX (Hurricane Rainband and Intensity Change Experiment) in 2005, and T-PARC (THORPEX Pacific Asian Regional Campaign) in 2008. He served as a principal investigator for PREDICT (Pre-Depression Investigation of Cloud Systems in the Tropics), which examined hurricane formation.Lee, Bell, and Paul Harasti of the Naval Research Laboratory also co-developed a tool called VORTRAC (Vortex Objective Radar Tracking and Circulation) that enabled hurricane specialists for the first time to continually monitor central pressure as a fast-changing storm nears land.A rich tradition of mentoringThe National Center for Atmospheric Research and the University Corporation for Atmospheric Research have a tradition of helping develop the next generation of scientists.In fiscal 2016 alone, there were more than 400 examples of NCAR and UCAR scientists and engineers working with student-scientists on activities such as mentoring, advising, thesis review, and teaching."There's no shortage of channels available to get great students from prestigious organizations, but the kind of informal programs like student assistantships show how NCAR opens the door for people who otherwise wouldn't get the opportunity," said Senior Scientist Wen-Chau Lee of NCAR's Earth Observing Laboratory.There are also several formal examples, including SOARS (Significant Opportunities in Atmospheric Research & Science), a UCAR program begun more than two decades ago to broaden participation in atmospheric sciences. In fiscal year 2016, about 65 student protégés either participated in SOARS internships or were supported through webinars and career advising.With mentoring opportunities from undergraduate internships through postdoctoral fellowships, NCAR|UCAR student-scientists have gone on to successful careers in government labs, academia, and the private sector, and many have taken on leadership roles. In the SOARS program alone, more than 100 students have earned a master's degree in science or engineering to date, and three dozen have gone on to get their Ph.D.s.While working at NCAR, Bell earned a master's degree in atmospheric science from Colorado State University and a Ph.D. in meteorology from the Naval Postgraduate School. The Education Assistance program of the University Corporation for Atmospheric Research paid tuition for his master's degree. (UCAR manages NCAR with sponsorship by the National Science Foundation.)"Michael always took advantage of the opportunities provided to him," Lee said. "There's an old saying of Confucius that to be a mentor or teacher is like being a big bell. The harder a student hits the bell, the greater the sound. If a student is eager to learn, I will put forward more from my end to challenge them."Graduate students at the University of Hawaii received radar training from Wen-Chau Lee (NCAR, far left) and Michael Bell (University of Hawaii, back row, second from left) in 2013 during an educational deployment of a Doppler on Wheels radar system that was sponsored by the National Science Foundation. Lee's participation was supported by the UCAR UVisit program. (Photo courtesy Wen-Chau Lee, NCAR.)Recalling Bell's early years, NCAR scientist Bob Rilling said: "Michael had a real curiosity and an analytical approach to problems. You could see his wheels turning. He wanted to make things work."The relationship between NCAR and Bell continued long after he moved on in his career.For example, in 2013, Bell invited Lee to the University of Hawaii as part of a UVisit program administered by UCAR. Lee gave lectures to Bell's radar class and helped Bell train graduate students during a Doppler on Wheels educational deployment as part of the Hawaiian Educational Radar Opportunity, a program sponsored by the National Science Foundation.Lee in turn asked Bell to become the principal investigator on a new project called the Lidar Radar Open Software Environment, or LROSE.LROSE aims to develop a unified open source software tool to handle the copious quantities of atmospheric data produced by radars and lidars. The collaboration won a competitive grant from the National Science Foundation Software Infrastructure for Sustained Innovation program, and a community workshop is planned for April at NCAR.Summing up NCAR's role in his professional life, Bell said, "I worked with a lot of good people, like Wen-Chau, and they really helped launch me into my current career."Writer/ContactJeff Smith, Science Writer and Public Information Officer  

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