The Deep Convective Clouds & Chemistry (DC3) Experiment, which began in mid-May, explores the influence of thunderstorms on air just beneath the stratosphere, a region that influences Earth's climate and weather patterns. Scientists used three research aircraft, mobile radars, lightning mapping arrays and other tools to pull together a comprehensive picture. Find out more in this news release.
An international team of researchers is studying how tropical weather brews in the Indian Ocean and moves eastward along the equator, with reverberating effects around the globe. The field campaign, known as DYNAMO or Dynamics of the Madden-Julian Oscillation, sought to help improve long-range weather forecasts and seasonal outlooks and enable scientists to further refine computer models of global climate. Find out more in this news release.
Summer storms are a regular feature in the North Atlantic, and while most pose little threat to U.S. shores, a choice few become devastating hurricanes. To decipher which storms could bring danger, and which will not, atmospheric scientists headed to the tropics to observe these systems as they formed and dissipated--or developed into hurricanes. By learning to identify which weather systems are the most critical to track, the efforts may ultimately allow for earlier hurricane prediction, and add several days to prepare for a hurricane's arrival. Find out more in this news release.
Credit: David T. Wright, National Science Foundation
From hurricane hunters flying through the eye of a storm to scientists analyzing the data to create more accurate models, National Science Foundation-supported researchers seek a better understanding of hurricane dynamics. They use a myriad of instruments equipped with sensors that measure such factors as wind speed, temperature, humidity, pressure and more. View the image here.
Credit: Nicolle Rager-Fuller, National Science Foundation
The eastern tropical Atlantic Ocean is out of range for U.S. hurricane-hunter aircraft, and forecasters have little skill predicting which systems brewing there will develop into hurricanes, atmospheric scientists say. To find out how some of the most dangerous hurricanes form, U.S. and French researchers launched large, specialized balloons carrying nearly 300 instruments over wide swaths of Africa and the Atlantic Ocean. Find out more in this news release.
Scientific research and the operational support of that research are the principal activities supported by the United States government in Antarctica. The goals are to expand fundamental knowledge of the region, to foster research on global and regional problems of current scientific importance, and to use the region as a platform from which to support research. For projects involving fieldwork, the U.S. Antarctic Program (USAP) supports only that research that can be done exclusively in Antarctica or that can be done best from Antarctica. NSF funds and manages the USAP. The Division of Antarctic Sciences (ANT) is one of two science divisions in NSF's Office of Polar Programs.
The Division of Atmospheric and Geospace Sciences (AGS) in the Directorate for Geosciences supports research to add new understanding of the behavior of the Earth's atmosphere and its interactions with the sun. NSF also provides support to operate the National Center for Atmospheric Research (NCAR).
September 24, 2012
Dropsondes--Work Horses in Hurricane Forecasting
Small cylinders dropped from airplanes gather atmospheric data on their way down
Inside a cylinder that is about the size of a roll of paper towels lives a circuit board filled with sensors. It's called a dropsonde, or "sonde" for short. It's a work horse of hurricane forecasting, dropping out of "Hurricane Hunter" airplanes right into raging storms. As the sonde falls through the air, its sensors gather data about the atmosphere to help us better understand climate and other atmospheric conditions.
"Dropsondes have a huge impact on our understanding of hurricanes and our ability to predict hurricanes," explains electrical engineer Terry Hock at the Earth Observing Laboratory in the National Center for Atmospheric Research (NCAR), located in Boulder, Colo.
With support from the National Science Foundation (NSF), Hock and his colleagues at NCAR have been designing, building and improving dropsonde technology for more than 30 years. "Our most current development is a fully automated dropsonde system for NASA's unmanned Global Hawk aircraft," says Hock.
Compared to earlier models, today's sondes are lighter weight, relatively inexpensive and loaded with sensors.
"We have a lot of electronics and, on the back side, a battery pack to operate the sonde. We have a temperature and two humidity sensors, and we have a GPS receiver," explains Hock, as he points out the different circuit board components. "As the sonde moves, we're using that GPS receiver to track the sonde's movements very precisely, which is then telling us the wind speed and wind direction. At the top of the sonde is a parachute which slows down the descent."
Electrical engineer Dean Lauritsen, a member of Hock's team, developed the system software on the aircraft, which controls the aircraft data system and process, and also displays dropsonde data during the sondes free fall to earth. There's such a system on the HIAPER, the NSF/NCAR Gulfstream V Research Aircraft, which uses sondes for scientific research, and a similar system used by the U.S. Air Force Reserve Hurricane Hunters in Biloxi, Miss., and the NOAA Hurricane Hunters in Tampa, Fla. On board each aircraft are a computer and a rack of electronic equipment to monitor and receive information from sondes. "The system is capable of tracking as many as eight dropsondes in the air at the same time. Each one of them is transmitting data on a separate frequency as it falls." says Lauritsen.
From the time the sonde leaves the aircraft, it is checking surroundings two times a second and sending information back to the aircraft, including pressure, temperature, humidity, wind speed, and wind direction. Future developments are expected to include sensors for chemicals such as ozone.
"We're taking vertical slices of the atmosphere constantly as the sonde falls," says Hock. "We're seeing very precise single measurements show up immediately on the computer screen."
Researchers process the information using NCAR-developed custom software, and then send it to weather forecasters and researchers around the world. In the case of the Hurricane Hunters, the information goes to the National Hurricane Center in Miami.
NCAR software engineer Charlie Martin develops custom software called ASPEN, which stands for Atmospheric Sounding Processing Environment. ASPEN helps make sense of all the dropsonde data. "Once the dropsonde has fallen through the atmosphere and the data has come back to the aircraft, that raw data needs a little more treatment before we send it to weather services around the world," explains Martin.
Martin points to a map showing a compilation of dropsonde wind data collected in August 2011, as Hurricane Irene was churning its way toward the Florida coast. "The winds are in a circular pattern," says Martin, as he identifies small triangles on the map that represent the wind and wind direction. "The center of the hurricane is clearly depicted in the center of the circular pattern. The National Hurricane Center uses this data along with other data to classify the hurricane and assign a category to it."
Hock and his team also custom fit aircraft with launchers to deploy the sondes, including one system for helium-filled balloons. In 2010, American and French researchers deployed balloons over Antarctica that dropped 600 sondes over a four-month period to study atmospheric conditions and the shifting ozone layer. "There is now a very dense set of measurements that came out of this project that has mapped the Antarctic atmosphere like it has never been done before," notes Martin.
"Atmospheric conditions above the Antarctic continent are hard to study since only a handful of sounding stations are regularly maintained there," says Peter Milne, program manager for ocean and atmospheric sciences within NSF's Office of Polar Programs. "Fortunately, the Antarctic polar vortex, a huge cyclone that sets up above the entire continent, is like the NASCAR of long distance ballooning, with balloons sweeping around the continent for as long as they stay aloft. Using these drifting platforms provided a unique data set."
Such "inside information" is helping scientists learn more about climate and hurricanes. Data from dropsondes is also giving scientists a better understanding about atmospheric conditions that spawn any number of weather conditions. Hock expects this will help forecasters make earlier and more precise hurricane predictions, giving people in the path of a killer storm more time to get out of harm's way.
Any opinions, findings, conclusions or recommendations presented in this material are only those of the presenter grantee/researcher, author, or agency employee; and do not necessarily reflect the views of the National Science Foundation.