Field Projects & Instruments

A favorable forecast for Kenyan students

November 30, 2016 | As scientists expand a program to provide critically needed weather observations in developing countries, they are forging a partnership with local schoolchildren and their teachers.The students and teachers are helping to oversee and maintain innovative weather stations, built largely with 3D-printed parts, at four schools in Kenya. By transmitting information about temperature, rainfall, and other weather parameters, the stations can help alert communities to floods and other potential disasters, as well as provide improved weather forecasts to local farmers, who are deciding when to plant and fertilize crops.NCAR scientist Paul Kucera describes the various components of the 3D-PAWS at the Sirua Aulo Maasai High School. (©UCAR. Photo by Kristin Wegner. This image is freely available for media & nonprofit use.) The weather stations, known as 3D-PAWS (for 3D-Printed Automated Weather Stations), are built with components that can be easily replaced if they wear out in the field. They were designed by weather experts at the National Center for Atmospheric Research (NCAR) and its managing entity, the University Corporation for Atmospheric Research (UCAR)."In my 30 years of doing fieldwork, this is one of the best deployments I've ever had," said NCAR scientist Paul Kucera. "At every school, we were joined by hundreds of students and dozens of teachers who wanted to learn more about the weather stations and the value of these forecasts."The weather stations were installed as a partnership with the Global Learning and Observations to Benefit the Environment (GLOBE) program, an international science and education initiative that encompasses tens of thousands of schools. This approach means that 3D-PAWS serves the dual purpose of educating students and improving forecasts."This is a great partnership to now extend our weather stations to schools," said Kristin Wegner, a project manager with the GLOBE Implementation Office, based at UCAR. "There is so much enthusiasm among the teachers and students because it's such a great learning tool as well as helping their communities."Students will learn about local weather and climate by comparing their weather observations to those taken at other schools using science protocols established by GLOBE. They can also assess the impacts of climate change on society and the environment, as well as see how the observations help with farming, flood prediction, and other applications.The installments took place during GLOBE's biannual Lake Victoria Learning Expedition, in which students and scientists from around the world explore the environment around the lake and discuss potential research collaborations. The expedition was coordinated by GLOBE Africa Regional Coordinator Mark Brettenny and  GLOBE Kenya Assistant Country Coordinator Charles Mwangi. Schools also received equipment donated from Youth Learning as Citizen Environmental Scientists.Needed: more stationsLike many developing countries, Kenya does not have detailed forecasts, partly because weather stations are scarce. The density of stations in Africa is eight times lower than recommended by the World Meteorological Organization. Building out a network can be prohibitively expensive, with a single commercial weather station often costing $10,000 to $20,000, plus ongoing funding for maintenance and replacing worn-out parts.To fill this need, UCAR and NCAR scientists have worked for years to come up with a weather station that is inexpensive and easy to fix and can be adapted to the needs of the host country. The resulting 3D-PAWS are constructed out of plastic parts that are custom designed and can be run off a 3D printer, along with off-the-shelf sensors and a basic, credit card-sized computer developed for schoolchildren.The total cost is about $300 per station. As the stations age, the host country can easily have replacement parts printed.Funding for the project comes from the U.S. Agency for International Development's Office of Foreign Disaster Assistance and the U.S. National Weather Service.Scientists installed the 3D-PAWS in Zambia earlier this year. Kenya is the second country to receive them."We're looking forward to installing more stations," Wegner said. "Additional schools are already asking about them."FundersU.S. Agency for International Development's Office of Foreign Disaster Assistance U.S. National Weather Service.PartnerGlobal Learning and Observations to Benefit the Environment (GLOBE)Writer/contact:David Hosansky, Manager of Media Relations

NSF/NCAR research plane assisting with U.S. hurricane forecasts

BOULDER, Colo. — As the peak of hurricane season approaches, U.S. forecasters are deploying a high-altitude research aircraft operated by the National Center for Atmospheric Research (NCAR) to fly over and around storms to take critical observations.The NSF/NCAR Gulfstream-V readies for takeoff on a mission to study tropical storms. (©UCAR. Photo by Carlye Calvin. This image is freely available for media & nonprofit use.) The deployment this week of the Gulfstream-V (G-V) aircraft is the result of a partnership between the National Science Foundation (NSF), which owns the plane, and the National Oceanic and Atmospheric Administration (NOAA), which issues forecasts. The NSF/NCAR G-V will take to the skies to support hurricane forecasts through October 12, while NOAA’s Gulfstream-IV (G-IV) undergoes unscheduled maintenance."It's critical to have detailed measurements of the atmosphere around a hurricane in order to ensure that forecasts are as accurate as possible," said Antonio (Tony) J. Busalacchi, president of the University Corporation for Atmospheric Research, which manages NCAR on behalf of NSF. "NCAR and its research partners have a proven track record of improving predictions of dangerous storms. Consistent with our role of managing NCAR, we take very seriously our ability and responsibility to share our advanced resources in support of NOAA's mission to protect life and property.""NSF is pleased that NCAR, using the G-V, is able to assist in this potentially lifesaving activity," said Roger Wakimoto, assistant director of the NSF Directorate for Geosciences. "The data gathered will help refine future hurricane forecasts.”Outfitted for critical observationsThe NSF/NCAR G-V can fly at high altitudes and deploy the same specialized sensors as the NOAA G-IV. These sensors take critical observations of atmospheric conditions for the NOAA National Hurricane Center.Studies show that such observations improve hurricane track forecasts in the U.S. global weather model (called the GFS) by about 15 percent during the 24 to 48 hours before landfall. Research also demonstrates that these data increase the accuracy of hurricane intensity forecasts.To take the observations, the NSF/NCAR G-V has been outfitted with the Airborne Vertical Atmospheric Profiling System (AVAPS). The system releases parachute-borne sensors, known as GPS dropsondes, that measure ambient temperature, pressure, humidity, wind speed, and wind direction at different altitudes as they fall through the atmosphere. Dropsondes were first developed at NCAR in the 1970s with NSF funding and have since been regularly updated. NOAA was an early adopter of the dropsondes for hurricane surveillance missions and research, and the development of the AVAPS system design in the 1990s was motivated in part by the capabilities of the NOAA G-IV.The NSF/NCAR G-V, which is available for flights over both the Atlantic and Pacific, will fly above a hurricane or other major storm at altitudes of up to 45,000 feet, as well as around the storm's edges. Its dropsonde launch system and software is similar to that of the NOAA G-IV.NCAR pilots will guide the aircraft on pre-planned flight tracks, dropping sondes approximately every 15 minutes. Data from the sondes will be processed by a NOAA technician onboard the plane, then sent to the Global Telecommunications System for immediate inclusion in hurricane forecast models."It is a special privilege for us to be able to help out our colleagues at NOAA by deploying the NSF/NCAR G-V in the hurricane surveillance missions this season," said Vanda Grubišić, director of NCAR's Earth Observing Laboratory, which operates the G-V. "Our Research Aviation Facility crews look forward to working with their NOAA colleagues and collecting important data in support of their mission."

3D-printed weather stations fill gaps in developing world

BOULDER — Scientists have successfully installed the first wave of low-cost weather stations that are designed to provide critically needed information to farmers and other residents in developing countries. The stations are built largely with 3D-printed parts that can be easily replaced if they wear out in the field. They were created by weather experts at the National Center for Atmospheric Research (NCAR) and its managing entity, the University Corporation for Atmospheric Research (UCAR). The first five stations, newly installed in Zambia, are beginning to transmit information about temperature, rainfall, winds, and other weather parameters. These measurements and the resulting forecasts can provide weather information for local subsistence farmers deciding when to plant and fertilize crops. They can also alert communities about floods and other potential disasters. A newly installed weather station at the Salvation Army's College of Biomedical Sciences in Chikankata, Zambia. The sensor on the left (with the funnel) is a specially designed tipping bucket rain gauge; the vertical, vented cylinder on the vertical arm of the station is a radiation shield containing temperature, humidity, and pressure sensors; and the horizontal cylinder protruding out the back contains a single-board computer. A wind vane (left), solar light sensor (middle), and three-cup wind anemometer (right) are mounted on the upper arm.  The station is powered by a single solar panel and a backup battery. (©UCAR. Photo by Martin Steinson. This image is freely available for media & nonprofit use.) "It’s a major opportunity to provide weather information that farmers have never had before," said NCAR scientist Paul Kucera, one of the project leaders. "This can literally make the difference when it comes to being able to feed their families." The scientists will next explore the need for low-cost weather stations in other developing countries. The project is funded by the U.S. Agency for International Development's Office of Foreign Disaster Assistance and the U.S. National Weather Service. “The bottom line is that 3D-printing will help to save lives,” said Sezin Tokar, a hydrometeorologist with U.S. AID. “Not only can they provide countries with the ability to more accurately monitor for weather-related disasters, the data they produce can also help reduce the economic impact of disasters.” Lack of observations Like many developing countries, Zambia does not have detailed forecasts, partly because weather stations are scarce. The density of stations in Africa is eight times lower than recommended by the World Meteorological Organization. Building out a network can be prohibitively expensive, with a single commercial weather station often costing $10,000 to $20,000, plus ongoing funding for maintenance and replacing worn-out parts. To fill this need, UCAR and NCAR scientists have worked for years to come up with a weather station that is cheap and easy to fix, and can be adapted to the needs of the host country. The resulting stations are constructed out of plastic parts that are custom designed and can be run off a 3D printer, along with off-the-shelf sensors and a basic, credit card-sized computer developed for schoolchildren. Total cost: about $300 per station. Best of all, the host country can easily print replacement parts. "If you want a different kind of wind direction gauge or anemometer, or you just need to replace a broken part, you can just print it out yourself," said project co-lead Martin Steinson of UCAR. "Our role is to make this as accessible as possible. This is entirely conceived as an open-source project." Building out a network Working with the Zambian Meteorological Department and other agencies, Kucera and Steinson installed the first stations earlier this year—three next to radio stations that will broadcast the information to local communities, one by a rural hospital, and one by the headquarters of the meteorological department. The meteorological office will take over the project later this year, with a goal of building out a network of 100 weather stations across Zambia. They will also have the 3D printers, materials, and training to maintain or upgrade the network. The weather station measurements are accessible to local meteorologists and also transmitted over wireless networks in real time to NCAR. After all the weather stations have been installed, scientists will develop a system of one- to three-day regional forecasts for Zambia using the NCAR-based Weather Research and Forecast (WRF) computer model. The forecasts, in addition to helping farmers and other residents, can also alert the country to the threat of impending floods or other weather-related disasters. The system will ultimately be transferred to the Zambian Meteorological Department to run the forecasts. "The objective of the project is to transfer the technology so this will be run by Zambia," Kucera said. Once the technology has been established in Zambia, Kucera and Steinson will turn to other nations that need additional weather stations, such as in Africa or the Caribbean. In addition to improving local forecasts, the additional observations can eventually make a difference for forecasts globally because computer models everywhere will have additional information about the atmosphere. "We’re hearing a lot of interest in using this technology in other countries," Kucera said. "It’s really quite a return on investment." Writer:David Hosansky, Manager of Media Relations

A CO2 milestone in Earth's history

(Illustration by Eric Morgan, Scripps Institution of Oceanography.) May 12, 2016 | Earth’s atmosphere is crossing a major threshold, as high levels of carbon dioxide (CO2)—the leading driver of recent climate change—are beginning to extend even to the globe's most remote region. Scientists flying near Antarctica this winter captured the moment with airborne CO2 sensors during a field project to better understand the Southern Ocean's role in global climate. This illustration shows the atmosphere near Antarctica in January, just as air masses over the Southern Ocean began to exceed 400 parts per million of CO2. The 400 ppm level is regarded as a milestone by climate scientists, as the last time concentrations of the heat-trapping gas reached such a point was millions of years ago, when temperatures and sea levels were far higher. The field project, led by the National Center for Atmospheric Research (NCAR) and known as ORCAS, found that there is still air present in the Southern Hemisphere that has less than 400 ppm of CO2—but just barely. In the north, the atmosphere had first crossed that threshold in 2013, as shown by observations taken at Mauna Loa, Hawaii, by the National Oceanic and Atmospheric Administration and Scripps Institution of Oceanography. Most fossil fuels are burned in the Northern Hemisphere, and these emissions take about a year to spread across the equator. As CO2 increases globally, the concentrations in the Southern Hemisphere lag slightly those further north. "Throughout humanity, we have lived in an era with CO2 levels below 400 ppm," said Ralph Keeling, director of the CO2 Program at the Scripps Institution of Oceanography and a principal investigator on ORCAS. "With these data, we see that era drawing to a close, as the curtain of higher CO2 spreads into the Southern hemisphere from the north. There is no sharp climate threshold at 400 ppm, but this milestone is symbolically and psychologically important." The air found by ORCAS with less than 400 ppm of CO2 was located in a wedge at lower altitudes. At higher altitudes, the air had already exceeded 400 ppm. This pattern is mostly a consequence of the way the air circulates in the region. At these southerly latitudes, the air arrives from the Northern Hemisphere at higher elevations and then mixes downward. Emissions of CO2 have been increasing since the 19th century. The measurements were taken by instruments operated by NOAA, NCAR, Scripps, Harvard University, and the University of Michigan. Scripps scientist Eric Morgan created this illustration. ORCAS was funded by the National Science Foundation. "This is the last we'll see of sub-400 ppm CO2 in the Southern Hemisphere, unless we're able to some day achieve negative emissions," said NCAR scientist Britton Stephens, co-lead principal investigator for ORCAS. "While 400 is just a number, for someone who was born when the atmosphere held 327 ppm of CO2, it’s certainly a reminder of our steadily increasing emissions and failure thus far to do enough to reduce them." About the image The illustration was created by interpolating 20 profiles measured on Feburuary 5 and 8, 2016. The vertical axis has been increased for better visibility. The image is freely available for nonprofit and media use. Please credit Eric Morgan, Scripps Institution of Oceanography. Writer/contact:David Hosansky, Manager of Media Relations

Flying lab to investigate Southern Ocean's appetite for carbon

BOULDER -- A team of scientists is launching a series of research flights this month over the remote Southern Ocean in an effort to better understand just how much carbon dioxide the icy waters are able to lock away. The ORCAS field campaign—led by the National Center for Atmospheric Research (NCAR)—will give scientists a rare look at how oxygen and carbon dioxide are exchanged between the air and the seas surrounding Antarctica. The data they collect will help illuminate the role the Southern Ocean plays in soaking up excess carbon dioxide emitted into the atmosphere by humans. "If we want to better predict the temperature in 50 years, we have to know how much carbon dioxide the oceans and terrestrial ecosystems are going to take up," said NCAR scientist Britton Stephens, co-lead principal investigator for ORCAS. "Understanding the Southern Ocean's role is important because ocean circulation there provides a major opportunity for the exchange of carbon between the atmosphere and the vast reservoir of the deep ocean." ORCAS is funded by the National Science Foundation’s Division of Polar Programs. "Building on decades of U.S. Antarctic Program research, new questions of global significance continue to emerge," said Peter Milne, program director of Ocean and Atmospheric Sciences in the Division of Polar Programs. "ORCAS addresses one of those questions: how the Southern Ocean affects global climate by storing, or releasing, carbon dioxide, water vapor, and heat.” Carbon dioxide, the main greenhouse gas contributing to human-caused climate change, is continually transferred back and forth between the atmosphere, plants on land, and the oceans. As more carbon dioxide has been released into the atmosphere by the burning of fossil fuels, oceans have stepped up the amount they absorb. But it's unclear whether oceans have the ability to keep pace with continued emissions. In the Southern Ocean, studies have disagreed about whether the ocean's ability to act as a carbon sink by taking up carbon dioxide is speeding up or slowing down. Measurements and air samples collected by ORCAS—which stands for the O2/N2 Ratio and CO2 Airborne Southern Ocean Study—will give scientists critical data to help clarify what's actually happening in the remote and difficult-to-study region. During the ORCAS campaign, the NSF/NCAR HIAPER research jet will study the air-sea exchange of gases over the Southern Ocean. Click image to enlarge. (Graphic by Alison Rockwell, NCAR. This image is freely available for media & nonprofit use.) Tracking carbon by air The ORCAS field campaign will operate out of Punta Arenas, near the southern tip of Chile. The researchers plan to use the NSF/NCAR HIAPER research aircraft to make 14 flights across parts of the Southern Ocean between Jan. 15 and Feb. 28. A suite of instruments on the modified Gulfstream V jet will measure the distribution of oxygen and carbon dioxide as well as other gases produced by marine microorganisms, plus aerosol and cloud characteristics in the atmosphere. The flights also will observe the ocean color—which can indicate how much and what type of phytoplankton is growing in the water—using NASA's Portable Remote Imaging Spectrometer (PRISM). The addition of the PRISM instrument to the ORCAS campaign was funded by NASA. The science campaign is being led by Stephens and NCAR scientist Matthew Long. Other principal investigators include Elliot Atlas (University of Miami), Michelle Gierach (NASA's Jet Propulsion Laboratory), Ralph Keeling (Scripps Institution of Oceanography), Eric Kort (University of Michigan), and Colm Sweeney (Cooperative Institute for Research in Environmental Sciences). CIRES is a partnership of the National Oceanic and Atmospheric Administration and the University of Colorado Boulder. The management of the field campaign is being handled by NCAR. Logistics include everything from obtaining diplomatic clearances from multiple countries to fly through their airspaces to providing housing and workspace for project scientists in South America. Carbon, oxygen, and phytoplankton Measuring oxygen alongside carbon dioxide can give scientists a clearer picture of the ocean processes affecting carbon dioxide than they would get from measuring carbon dioxide alone. "The air-sea exchange of carbon dioxide is controlled not just by physics but also by biology," Long said. "There's a nice relationship between the fluxes of oxygen and the fluxes of carbon dioxide that can be exploited to gain insight into these processes." Carbon dioxide in the ocean is drawn into a chain of chemical reactions that buffer the impact of biological and physical ocean processes on carbon dioxide in the overlying atmosphere. Oxygen air-sea fluxes, however, are more directly tied to these same biological and physical factors. So if scientists know what's going on with oxygen, they can better understand the processes affecting carbon dioxide as well. The Southern Ocean, which encircles Antarctica, is an especially important carbon sink. The ORCAS field campaign will help scientists better understand whether the Southern Ocean's ability to take up carbon is keeping pace with a continued increase in carbon dioxide emissions by humans. (Photo courtesy of the U.S. Central Intelligence Agency.) Additionally, if scientists know how the concentrations of the two gases change relative to one another with location and time, they can disentangle how biology and physics separately affect the ocean's ability to absorb carbon dioxide. Physics and biology affect the ratio of carbon dioxide to oxygen in the air in different ways. In the austral spring the warmth of the returning Sun drives both carbon dioxide and oxygen out of the Southern Ocean surface and into the atmosphere. But the sunlight also triggers the growth of phytoplankton in the water. As the organisms begin to flourish, they take in carbon dioxide and release oxygen, causing the relative amounts of those two gases in the atmosphere to shift in opposite directions. Observations of these shifts can ultimately tell scientists how much carbon is going where and, more importantly, why. A window into the deep ocean The Southern Ocean is unique among Earth's oceans. Unimpeded by continental landmasses, and driven by a westerly wind, the Southern Ocean is able to form a circular current around Antarctica. This huge flow, the largest current on the planet, connects the adjacent Atlantic, Pacific, and Indian oceans. The complex interactions between this Antarctic Circumpolar Current and currents flowing in from other ocean basins creates an overturning circulation that brings deep water to the surface where it can exchange gases with the atmosphere before it is returned to depth. Once it dives toward the ocean floor, that surface water—and any carbon dioxide it takes with it—can stay sequestered in the deep ocean for hundreds or even thousands of years. Data collected by the ORCAS flights will help determine how much carbon dioxide goes along for the ride. "The Southern Ocean provides a window into the deep ocean, but it's a difficult system to simulate in our Earth system models," Long said. "It's remote, and so there has been a paucity of observations that can be used to improve the models we have." The data generated during the field campaign will be used by the ORCAS team to improve these global computer models so they do a better job representing the complexities of the Southern Ocean. The data set, which will be managed by NCAR, will be publicly available. While the measurements made during the ORCAS campaign will help scientists fine-tune what they know so far about the Southern Ocean, it's possible the project will also bring to light entirely new aspects of how the ocean works. "The Southern Ocean is very inaccessible, and existing measurements are from ships or surface stations that represent only a few tiny dots on a huge map," Stephens said. "The airborne measurements we take will be helpful in terms of understanding the system better. And because we're doing something that no one's ever done before, we're likely to find things that we aren't expecting." The NSF’s Division of Polar Programs manages the U.S. Antarctic Program, through which it funds researchers, coordinates all U.S. government research on the southernmost continent, and provides logistical support needed to make the science possible. WriterLaura Snider, Senior Science Writer and Public Information Officer

Cloud droplets in 3D

October 1, 2015 | It seems like a simple question: When a wet cloud mixes with dry air, do the cloud's droplets evaporate completely one by one? Or do all the droplets shrink simultaneously, each giving up a tiny bit of its water at the same time? The two theories of what might happen to water droplets when clouds begin to dissipate were proposed more than 30 years ago. But evidence as to which one might be correct—information that could improve how clouds are represented in weather and climate models—has been hard to come by. The instruments traditionally used to measure droplets in clouds cannot view individual droplets in three dimensions while simultaneously recording the sizes of each droplet. The Holographic Detector for Clouds (HOLODEC) mounted on the wing of a research aircraft.  (Photo by Scott Spuler, ©UCAR. This image is freely available for media & nonprofit use.) That just changed. An experimental instrument built at the National Center for Atmospheric Research (NCAR) in collaboration with Michigan Technological University has given scientists a detailed look inside clouds using holography, the technique used to make holograms. What they learned, detailed in a new study published in the journal Science, is that droplets tend to either evaporate entirely or remain untouched. (Read more about the new study.) The Holographic Detector for Clouds (HOLODEC) uses laser light to take a 3D "image" of the droplets inside the cloud.  "It's a combination of camera technology and computing technology," said NCAR scientist Jeff Stith, a cloud physicist who heads NCAR's Research Aviation Facility. "The instrument basically takes a hologram of a thousand or so particles and the computer reconstructs each droplet. It's a huge computational effort that wouldn’t have been possible years ago." Profile of the ultraviolet laser beam used to generate the holograms. (Image by Scott Spuler, ©UCAR. This image is freely available for media & nonprofit use.) Stith is a co-author of the new study in Science along with NCAR research engineer Scott Spuler, who designed the optics for HOLODEC. Spuler worked on the instrument with study co-author Jacob Fugal when Fugal was a postdoctoral fellow through NCAR's Advanced Study Program. Fugal, who earned his doctoral degree at Michigan Tech, is now at the Johannes Gutenberg University of Mainz and the Max Planck Institute for Chemistry. Stith and Spuler worked with researchers from Michigan Tech to install HOLODEC on the wing of the National Science Foundation/NCAR C-130 and to fly the airborne laboratory into an appropriate cloud. Now that the results of the flight are published, Stith expects to hear from more scientists who believe HOLODEC could be useful in their own work. "The instrument is still somewhat experimental," he said. "But we anticipate it will be highly requested in the future." About the Article Matthew J. Beals, Jacob P. Fugal, Raymond A. Shaw, Jiang Lu, Scott M. Spuler, Jeffrey L. Stith. Holographic measurements of inhomogeneous cloud mixing at the centimeter scale, Science, doi: 10.1126/science.aab0751 Writer/ContactLaura Snider FundersNational Science FoundationU.S. Department of Energy      

A cool setting for hurricane births

September 9, 2015 | One of the biggest mysteries about hurricanes has to do with their very beginnings. Certain clusters of thunderstorms over warm ocean waters gradually spin up into tropical storms and hurricanes while others simply dissipate—but scientists aren’t sure why. New research by NCAR scientist Chris Davis aims to shed light on this issue. Davis, director of NCAR’s Mesoscale and Microscale Meteorology Lab, focuses on the role of downdrafts that produce relatively cool pockets of air near the surface prior to the formation of tropical cyclones. The cool pools can, in turn, trigger vigorous updrafts. These vertical movements of air enable a rotation several miles up to generate a vortex near the surface, which then intensifies into a tropical cyclone. The research is appearing in the Journal of the Atmospheric Sciences.  "This is a surprising result," Davis said of the role of cool pools. "It may help us reconcile some of the seemingly disparate theories about hurricane genesis." A satellite image captured this 2010 storm just as it was strengthening into Tropical Storm Karl. Karl and other storms observed during the PREDICT field campaign provided evidence that the presence of relatively cool pockets of air near the ocean surface may play a role in the development of tropical storms and hurricanes. (Image courtesy Naval Research Lab.) Davis’s interest in the cool pools stems from a major field project, known as the Pre-Depression Investigation of Cloud Systems in the Tropics (PREDICT). The National Science Foundation–funded project deployed a specially equipped research aircraft to take numerous observations of the atmosphere over the tropical Atlantic Ocean during the 2010 hurricane season with the goal of better understanding how hurricanes form. Davis and his colleagues noticed that, in regions where tropical storms were forming, the observations showed that the lower part of the atmosphere contained pools of air that were about 2 degrees Celsius cooler than surrounding air. To learn more about these cool pools, Davis turned to a specialized NCAR computer model of clouds to run a set of simulations of an idealized, rotating atmosphere above a uniform tropical ocean. In these conditions, random thunderstorms would join into clusters and gradually spin up a vortex about three miles above the surface.  Cool pockets of air near the surface then consistently emerged within larger regions of warm air prior to the development of a surface vortex. "The simulations produced a temperature profile that was very similar to the observations," Davis said. Penetrating down to the surface While tropical cyclone researchers have known about the rotations higher up, they have long puzzled over how such rotations penetrate to the surface where they can tap the fuel of the warm upper ocean. Davis conjectures that the cool pools may hold the key for a couple of reasons: As thunderstorms rain down, they produce downdrafts that cool the air near the surface. The larger and more organized the thunderstorms, the more pronounced the cooling of patches of surface air. The contrast between the pools of cool air and the surrounding, warmer air produces updrafts at lower altitudes.  The result is more convergence of air near the surface, which, like the ice skater pulling in his or her arms, creates faster rotation. A major challenge for this research, Davis added, is that the observations of cool pools taken during PREDICT were spaced about 100 miles apart, which were too dispersed to show regions of warm air in between. But without the contrasting regions of warm and cooler air, there would not be strong updrafts. By using the model, Davis was able to get a fuller picture. "The results from the simulations, despite being highly idealized, give us a clue about resolving the inconsistency," Davis said. "The gradients in temperature matter." Davis said the cool pools can advance our understanding of hurricane genesis. But he emphasizes that more research is needed with more complex models and better observations to resolve competing ideas. Some research points to a top-down process, with the vortex aloft controlling surface vortex formation. Other research indicates a bottom-up process in which clouds known as “hot towers” carry warm moist air from the ocean surface to the lower stratosphere. The cool pools could incorporate aspects of both processes, with the vortex aloft generating the thunderstorms and their attendant downdrafts and cool pools of air, but the surface conditions helping to spur new updrafts that actually intensify the surface vortex. Such a process of organizing updrafts, Davis said, would be similar to squall lines over land, in which cool pools help lift the air on the flanks of the storms. "While we haven’t had the instruments to observe the formation of hurricanes in this detail, it might be that the processes over water resemble some of the processes over land in the earliest stages of hurricane formation," Davis said. About the article Davis, Chris. The Formation of Moist Vortices and Tropical Cyclones in Idealized Simulations, Journal of the Atmospheric Sciences, doi: 10.1175/JAS-D-15-0027.1 Writer/contact:David Hosansky Funder:National Science Foundation

3D printers promise affordable weather stations for the developing world

July 22, 2015 | A well-knit network of weather stations is critical to making accurate regional forecasts and understanding the long-term impacts of a changing climate. But in parts of the developing world, working weather stations are few and far between. Fixing the problem could require significant international investment, extensive training of technicians, and a bevy of costly meteorological equipment—or maybe just a 3D printer, some off-the-shelf sensors, and a cheap, credit card-sized computer developed for school kids. Technologists Kelly Sponberg and Martin Steinson think the latter is a possibility for filling in the often substantial distances between high-tech weather stations in places like Africa, where the density of stations is eight times lower than recommended by the World Meteorological Organization. Sponberg and Steinson develop new tools for the meteorology community through the Joint Office of Science Support (JOSS), a program of the University Corporation for Atmospheric Research. Paul Kucera, an NCAR scientist, holds a wind direction gauge while checking connections and cables for a prototype 3D-printed weather station at a test site outside Boulder. The vertical, vented cylinder at right is a radiation shield containing temperature, humidity, pressure, and altitude sensors. The funnel on the left contains a specially designed precipitation gauge. The horizontal cylinder protruding out the back contains a single-board computer. (©UCAR. Photo by Carlye Calvin. This image is freely available for media & nonprofit use.) In countries where resources are tight, it's been a long-term challenge to come up with the funds to pay for weather-observing equipment. Even when money is provided, sometimes by international organizations, it's not uncommon for a broken piece of equipment to stay offline since local technicians rarely have the training or specialized parts needed to come up with a fix. JOSS has been focusing on this problem for years. One past solution involved installing high-end consumer weather stations, each costing around $1,000. These relatively inexpensive installations were good enough to provide some basic observations, but they weren't customizable. When they started to fail, parts couldn't be replaced because the manufacturers had long since quit making them. So Sponberg and Steinson turned their attention to building a weather station that is affordable, made to order, and easy to fix. "It's the right time for something like this," Sponberg said. "There's an explosion of cheaper and cheaper sensors, cheaper and cheaper computing systems, and cheaper and cheaper manufacturing technologies, like 3D printers. All we had to do is bring it all together." Print it, use it, break it—print it again The result is the Micro-Manufacturing and Assembly (MMA) project. The idea is to print the pieces of the weather station—which would vary depending on what the national meteorological service in a particular country wants—plug in off-the-shelf sensors, and use Raspberry Pi, a tiny low-cost computer originally developed by a nonprofit foundation to teach basic coding, as the station's brains. The price of parts and materials is about $200 per weather station. Funding for the project comes from the U.S. Agency for International Development. As pieces break, or a country's meteorological service decides it wants to tweak or expand the station's capabilities, new parts can be printed and sensors can be easily upgraded. "This is an open source project," Sponberg said. "You can design the station and build it yourself, and, after a few years, if you decide you want the anemometer to work better or in a different way, for example, you have the tools to just print that yourself." For the last year, a prototype 3D-printed station has been put through its paces—enduring rain, snow, wind, and the sometimes unrelenting Colorado sunshine—at UCAR's Marshall field site south of Boulder. So far, the materials seem to be holding up well. Once the prototype has proven both sturdy and reliable, the plan is to begin deploying stations in the field, perhaps late this year. Determining where stations are installed, however, will be as important as how well the stations work. For a project to be successful, the local community has to support it, Sponberg and Steinson said. Getting buy-in from the local community requires understanding local needs and how better weather observations—which can ultimately create better local forecasts—can help meet those needs, they said. Involving the community in the design process is also essential. The team is focusing on Zambia for the initial location because they've worked there in the past and can tap into existing relationships to make sure the community is involved. "The community needs to value the weather observations and the weather station," Sponberg said. "The observation network will only survive if there's a human network behind it." UCAR's Martin Steinson examines a rain gauge, one of the key weather station components produced by 3D printing. (©UCAR. Photo by Carlye Calvin. This image is freely available for media & nonprofit use.) Writer Laura Snider Contact David Hosansky Funder U.S. Agency for International Development

Scientists tackle mystery of thunderstorms that strike at night

BOULDER – Thunderstorms that form at night, without a prod from the Sun's heat, are a mysterious phenomenon. This summer scientists will be staying up late in search of some answers. From June 1 through July 15, researchers from across North America will fan out each evening across the Great Plains, where storms are more common at night than during the day. The research effort, co-organized by the National Center for Atmospheric Research (NCAR) and several collaborating institutions, will use lab-equipped aircraft, ground-based instruments, and weather balloons to better understand the atmospheric conditions that lead to storm formation and evolution after sunset. Their results may ultimately help improve forecasts of these sometimes damaging storms. The Plains Elevated Convection at Night (PECAN) field campaign will involve scientists, students, and support staff from eight research laboratories and 14 universities. The $13.5 million project is largely funded by the National Science Foundation (NSF), NCAR's sponsor, which contributed $10.6 million. Additional support is provided by NASA, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Department of Energy. Aloft in the night Thunderstorms that form during the day are less puzzling than nighttime storms. The Sun heats the Earth’s surface, which in turn, warms the air directly above the ground. When that warm air is forced to rise, it causes convection—a circulation of warm updrafts and cool downdrafts—and sometimes creates a storm. The formation of thunderstorms at night, however, when the Sun is not baking the land, is less well understood. "At night, the entire storm circulation is elevated higher off the ground," said NCAR scientist Tammy Weckwerth, a PECAN principal investigator. "This makes observations of the conditions leading to nighttime thunderstorms much more challenging because that part of the atmosphere is not well covered by the network of instruments we normally rely on. The vast array of instruments available to PECAN researchers will allow them to collect data higher in the atmosphere. This data will help scientists characterize the conditions that lead both to individual storm formation as well as to the clustering and organizing of these storms into large-scale systems, which can drop significant precipitation. "Nighttime thunderstorms are an essential source of summer rain for crops but are also a potential hazard through excessive rainfall, flash flooding, and dangerous cloud-to-ground lightning," says Ed Bensman, program director in NSF’s Division of Atmospheric and Geospace Sciences.  "Weather forecast models often struggle to accurately account for this critical element of summer rainfall on the Great Plains.  The PECAN field campaign will provide researchers and operational forecasters with valuable insights into thunderstorms at night—and improve our ability to model them more accurately." Deploying in the dark The campaign, based in Hays, Kansas, will begin each day at 8 a.m., when a crew of forecasters starts developing a nightly forecast. At 3 p.m. the scientists will use the forecast to determine where across northern Oklahoma, central Kansas, or south-central Nebraska to deploy their mobile resources. Moving dozens of people around the Great Plains each night will be a challenge for PECAN, but it's also what distinguishes it from past field projects.  "Previous severe weather campaigns have focused mostly on daytime storms, for largely practical reasons, as it is more difficult to set up instruments in the dark," said Bart Geerts, a professor of atmospheric science at the University of Wyoming and a PECAN principal investigator. "But the large thunderstorm complexes travelling across the Great Plains at night really are a different beast." NCAR's portable S-Pol radar is one of the many instruments that will be deployed during the PECAN field campaign to help scientists better understand nighttime thunderstorms. (©UCAR. This image is freely available for media & nonprofit use.) Scientists believe that several interacting factors may contribute to nocturnal storm formation and maintenance: a stable layer of air at the surface; a strong wind current above that layer, known as a low-level jet; and atmospheric waves, some of which are called "bores," that ripple out from the storms themselves.  "But we just don't really know how they interact," Geerts said. "That's what PECAN is about." A better understanding of these storms will have relevance for areas beyond the Great Plains. Clustered nighttime thunderstorms are common in various regions scattered across the globe. A fleet of instruments PECAN will use three research aircraft, two of which—a University of Wyoming King Air and a NASA DC-8—will fly in the clear air away from the storms. Only the third, a NOAA P-3, which is widely used in hurricane research and reconnaissance, will be able to fly into the trailing region of storms.   The researchers will also rely on a number of ground-based instrument suites, known as PECAN Integrated Sounding Arrays, or PISAs. Six of the PISAs will operate from fixed locations around the study area, and four will be mobile, allowing them to be repositioned each night depending on where storms are expected to form. The instruments within each PISA vary, but collectively they will give each array the ability to measure temperature, moisture, and wind profiles, as well as launch weather balloons. Among the instruments are several newly developed at NCAR's Earth Observing Laboratory (EOL), including one that uses an innovative laser-based technique to remotely measure water vapor and an advanced wind profiler. Finally, the scientists will have a fleet of mobile and fixed radars, including the NCAR S-Pol. In all, PECAN researchers will have access to more than 100 instruments brought to the effort by partner institutions from across North America. "The sheer number of instruments being coordinated is unprecedented," said Weckwerth, who has participated in more than 15 other field expeditions. The planning necessary to manage this large collection of instruments—from finding property suitable for a fixed radar to making sure the mobile instruments are out of harm's way while tracking a storm—is being taken on by EOL's Project Management Office. That team is also responsible for housing, food and other logistics for the scientists and students who are participating in the campaign.

Nor’easter on the radar

February 9, 2015 | While some folks were looking to Punxsutawney Phil on Groundhog Day, scientists were learning about the weather through a different route: flying a highly advanced cloud radar on its maiden voyage above a major northeast storm. The dual-polarization radar, developed at NCAR with funding from NSF, is a compact instrument that uses millimeter-long wavelengths of energy to provide highly detailed views of the atmosphere. It distinguishes between ice, water, and supercooled water droplets (droplets that exist as a liquid below freezing), measures thin ice and liquid clouds, and takes advanced wind measurements. Scientists flew the new HIAPER Cloud Radar, mounted in the white pod, over a Nor'easter to capture detailed data about a major winter storm. (Photo by Jonathan Emmett, NCAR. This image is freely available for media & nonprofit use.) The new instrument is designed to fly aboard the specially instrumented NSF/NCAR Gulfstream V aircraft, also known as the High-performance Instrumented Airborne Platform for Environmental Research (HIAPER). For that reason, it is called the HIAPER Cloud Radar. A scientific team led by University of Illinois atmospheric scientist Bob Rauber deployed the radar on February 2 for eight hours, gathering data from Washington, D.C., to Bangor, Maine. Flying over a storm that was pummeling the region with snow, freezing rain, and strong winds, the scientists obtained clear and detailed observations of various features within the storm, including circulation patterns and small regions near the top of the clouds called generating cells that contain up-and-down drafts and generate the snow that later reaches the ground. The one-day field project, known as Nor’easter, will help scientists better understand the conditions that lead to the distribution of precipitation within the storm. It may eventually lead to finer-grained forecasts that can project which locations within a region are likely to receive the most snow. Northeastern winter storms draw energy from warm Atlantic water, developing bands of exceptionally heavy snow. This creates a major forecasting challenge for the densely populated Northeast where the locations of such bands can mean the difference between a foot of snow falling on Manhattan or on less developed regions just 50 or 75 miles away. “We are hoping to understand how the circulation patterns we saw so clearly on the HIAPER Cloud Radar organize snowfall,” Rauber said. “The data from the Nor’easter Project will be valuable to forecasters and researchers studying Northeast snowstorms, helping them interpret the computer model results and observations by ground radar.” The research team was excited to put the new radar through its paces and said it passed its maiden voyage with flying colors. “The HIAPER Cloud Radar, together with the long range and endurance of HIAPER, will allow atmospheric scientists the flexibility to explore regions of storms that would be impossible to reach with ground-based radars,” said Jeff Stith, manager of NCAR’s Research Aviation Facility. “For example, they can use it to study the formation of large storm systems approaching the East Coast from the Atlantic Ocean. We expect it to be widely used in future missions, often in combination with other measurements that can be made from HIAPER.” The wait won't be long. The radar's next deployment will be this summer, when a field project known as CSET (Cloud-System Evolution in the Trades) gets underway. CSET researchers will head to the Pacific to examine the evolution of cloud systems in the important trade-wind regions, which can influence climate worldwide. The NSF/NCAR HIAPER Gulfstream V research jet in flight. (©UCAR. This image is freely available for media & nonprofit use.)  Writer/contactDavid Hosansky Nor’easter CollaboratorUniversity of Illinois Nor’easter & HIAPER Cloud Radar FunderNational Science Foundation    

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