Additional European Research Projects
NCAR engineer Scott Spuler is helping to design DIAL. (Photo by Carlye Calvin, UCAR Digital Image Library.)
A Laser-Sharp Look at Water Vapor
Water vapor is a fundamental ingredient in the global system of precipitation and evaporation, and it influences worldwide climate as Earth’s most important greenhouse gas.
Yet scientists are limited in the ways they can measure water vapor in the atmosphere. Balloon-borne radiosondes usually collect data only for widely scattered points in the atmosphere, and satellite-mounted instruments cannot provide sufficient resolution for many research and forecasting applications.
NCAR researchers, working with colleagues at the University of Hohenheim in Germany, are designing a new instrument called a differential absorption lidar (DIAL) that may give scientists far more comprehensive measurements of water vapor in the atmosphere. By sending out pulses of light at two different wavelengths, DIAL is capable of extremely sensitive water vapor volume measurements.
Among other components, NCAR is developing a 1-meter telescope to receive light pulses that are reflected back to the instrument after scattering off small particles and molecules in the atmosphere. University of Hohenheim researchers are focusing on the laser transmitter. The two institutions are collaborating on a signal detection system.
Once completed, DIAL “will be one of a kind in the world in terms of performance,” predicts NCAR scientist Shane Mayor, who is helping to oversee the project.
Weather’s Far-Flung Links
As scientists piece together the global nature of our climate system, they are just beginning to understand atmospheric patterns that can affect weather in widely separated regions of the world. A wet winter over part of the Atlantic Ocean, for example, might correlate with unusually dry conditions thousands of miles away.
NCAR scientist Grant Branstator is researching circumglobal teleconnections, the connections among a series of atmospheric fields that influence winds and storm paths in much of the Northern Hemisphere. He is working with Dutch scientists on an extraordinarily large series of experiments that can shed light on how climate change may alter the fields and significantly affect weather patterns in North America, Europe, Asia, and elsewhere.
The Royal Netherlands Meteorological Institute initiated the experiments to see whether storm surges would become more likely in coming decades and threaten that low-lying country’s system of dykes. The institute, working with Branstator and other NCAR scientists, generated 62 computerized scenarios on the powerful Community Climate System Model at NCAR to look at the potential impacts of climate change by simulating climate from 1940 to 2080.
Model projections show that the Northern Hemisphere, by 2080, may contain regions of unusually high or low pressure (shown here in red and blue, respectively). This would alter the path of the jet stream and affect the positions of storm tracks. (Courtesy Grant Branstator, NCAR.)
In addition to producing more information on storm surges, the simulations revealed a remarkable change in both upper- and lower-atmospheric conditions in winter. By 2080, climate change may shift atmospheric fields that are characterized by particular patterns of winds, pressure, and precipitation, thereby altering the path of the jet stream. Among the results: powerful storms farther to the south over parts of the Atlantic and decreased wintertime precipitation in certain other regions.
The team is continuing to collaborate to learn more about why climate change may cause such a shift and what the likely regional impacts would be.
THREDDS enables users of client software, such as the Unidata Integrated Data Viewer, to work with data sets on remote servers. Here the IDV shows at a glance a computer model’s forecast of surface temperatures (color-coded map), areas of high winds aloft (green shapes), and patterns of upper-level pressure (contour lines). (UCAR, courtesy Unidata)
Locating the right data can be an ongoing challenge for researchers and educators. A study of the landfall of a hurricane, for example, may involve tracking down data sets from satellites, radars, computer forecast models, and other sources, and then converting the data into a usable format—a task that may very well take months before a researcher can even begin an analysis.
UCAR is working with collaborators at several U.S. and European institutions to develop an online system to help scientists, educators, and students find usable data far more quickly. The system, known as Thematic Real-time Environmental Distributed Data Services, or THREDDS, is designed to give users ready access to a large collection of both real-time and archived data sets from government and private sources.
“The overall concept is to make scientific data sets an integral part of the World Wide Web, so researchers can find, analyze, and visualize data as easily as they now find and manipulate text and images,” explains Ben Domenico, who oversees the project at UCAR's Unidata office.
THREDDS will offer an innovative feature, known as data interactive documents, that will allow a reader to validate or build on the research in a journal article by immediately accessing the same raw data used by the author, along with the same analysis and display tools.
Scientists at the University of Florence, Britain’s Natural Environment Research Council, the International University Bremen, and other European organizations are creating a standard interface for the new technology. The project, which also involves collaborators in Canada and several dozen U.S. academic and private sector institutions, will allow researchers and educators to focus more on scientific concepts while worrying less about the underlying formats of the data sets.
European Collaborations
A Laser-Sharp Look at Water Vapor
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