Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hurricane Study to Tackle Long-Standing Mystery

29.07.2010
Scientists are launching a major field project next month in the tropical Atlantic Ocean to solve a central mystery of hurricanes: why do certain clusters of tropical thunderstorms grow into the often-deadly storms while many others dissipate? The results should eventually help forecasters provide more advance warning to those in harm's way.

"One of the great longstanding mysteries about hurricanes is how they form," says Christopher Davis, a scientist with the National Center for Atmospheric Research (NCAR) and a principal investigator on the project. "There are clusters of thunderstorms every day in the tropics, but we don't know why some of them develop into hurricanes while others don't. We need to anticipate hurricane formation to prepare for hazards that could develop several days later."

PREDICT, the Pre-Depression Investigation of Cloud Systems in the Tropics, will run from August 15 to September 30, the height of hurricane season. The project is funded primarily by the National Science Foundation (NSF), NCAR's sponsor.

In addition to NCAR, collaborators include the Naval Postgraduate School, University at Albany-SUNY, University of Illinois at Urbana-Champaign, University of Miami, NorthWest Research Associates-Redmond,WA, New Mexico Tech, Purdue University, and University of Wisconsin-Madison.

Based on St. Croix in the U.S. Virgin Islands, PREDICT will deploy the NSF/NCAR Gulfstream V research aircraft. The G-V jet, also known as HIAPER, has a range of up to 7,000 miles and will reach an altitude of about 43,000 feet, enabling scientists to take observations near the tops of storms that form thousands of miles from the coast.

By better understanding the formation of tropical storms that may become hurricanes, scientists can help the National Hurricane Center attain the goal of seven-day hurricane forecasts, rather than the current limit of five days. Long-term predictions are needed by shippers, offshore oil operators, emergency managers, and others involved in public safety to better prepare for incoming storms.

Currently, many storms develop too quickly for society to make sufficient preparations. In 2007, for example, scattered thunderstorms in the Atlantic Ocean organized into a larger-scale storm system that quickly grew into Hurricane Felix, a category 5 storm that caused widespread loss of life and destruction in Nicaragua and Honduras.

-----Three projects with a common purpose-----

The PREDICT flights will be coordinated each day with flights for two other hurricane studies taking place this summer. NASA is leading a project known as GRIP (Genesis and Rapid Intensification Processes), while the National Oceanic and Atmospheric Administration (NOAA) is leading IFEX (Intensity Forecasting Experiment).

Although the three projects are independent, their observations have the potential to capture the complete evolution of one or more hurricanes from formation until landfall, as well as capture non-developing storms that are equally important for understanding why some disturbances develop beyond the wave stage while many others do not.

"We hope the information we gather this summer will unlock some of the secrets of how hurricanes form and evolve," Davis says. "This is key information we all need to better protect lives and property from major storms."

-----Rotating updrafts and marsupial pouches-----

One of the central goals of PREDICT is to pinpoint the differences between a tropical thunderstorm cluster that is capable of growing in power and one that is likely to weaken.

Scientists theorize that part of the secret may lie in the 3-D air motions within a larger system, such as a tropical easterly wave or a subtropical disturbance, that can serve as a safe haven for rotating thunderstorms. As these thunderstorms draw in rotating air from their sides, they can develop increasingly powerful, tightly wound circulations, analogous to figure skaters who spin faster and faster by drawing their arms inward. In contrast, strong downdrafts that reach the surface and spread out can slow the spin of the storm. When a thunderstorm cluster is surrounded by a deep layer of moist air, the likelihood of downdrafts is significantly reduced.

But the problem of hurricane formation is not as simple as the formation of one or several rotating thunderstoms, which persist typically for a few hours at most. To unlock the mystery one must look also at the larger-scale environment, including the structure and composition of the large-scale disturbances and tropical easterly waves that encompass clusters of thunderstorms.

PREDICT will focus on regions where tropical easterly waves and embedded thunderstorm complexes are most likely to form tropical storms. The project will gather data across areas as large as 500 by 500 miles, using remote sensing instruments on NOAA and NASA aircraft to probe for details within these preferred regions of development.

Some scientists have advanced a concept, known as the "marsupial pouch," that they believe is key to tropical cyclone development. According to this hypothesis, if a storm cluster moves at a similar speed to the surrounding flow in the lower to middle troposphere and is not adversely deformed by horizontal wind shear, then it is largely protected from being torn apart. This protective environment, known informally as the "marsupial pouch," can also help insulate storms from dust and dry air that might impede their growth. Within such a protective pouch, the system could draw energy from warm ocean waters, develop a closed circulation of winds, and form a tropical depression, perhaps eventually becoming a tropical storm or hurricane.

"We think the marsupial pouch provides a focal point or 'sweet spot' where favorable conditions could persist for several days and where rotating thunderstorms are most likely to aggregate into a larger-scale storm," says Michael Montgomery, a PREDICT principal investigator and a professor at the Naval Postgraduate School. "This would dramatically increase the chances of a tropical depression or larger storm forming."

The findings from PREDICT will be particularly useful for forecasts in the North Atlantic. However, the results will also help forecasters in parts of Asia and Australia where coastlines are vulnerable to typhoons and cyclones (as hurricanes are known there). The findings may also help provide important insights into the equally difficult question of whether climate change will significantly increase the frequency or intensity of these powerful storms.

"If we can better understand the processes that lead to hurricanes, we can apply that knowledge to our changing climate and how it is likely to influence future tropical storms and hurricanes," Davis says.

-----Measurements in a remote environment-----

Part of the reason that hurricane formation has remained such a mystery is that scientists have comparatively little information in general about storms that develop over the ocean. Observations from ships and aircraft are few and far between, while satellites have difficulty providing wind and temperature information beneath cloud tops within a storm.

The PREDICT research team will fly near thunderstorm complexes and probe the surrounding environment once or twice per day when tropical systems of interest come within about 1,500 miles of St. Croix. Using dropsondes (parachute-borne instrument packages) and a variety of other instruments, they will take measurements of temperature, humidity, wind speed and direction, and water vapor. They will also gather fine-scale details of clouds, including ice particles and water droplets. One of the main goals is to take measurements of airborne Saharan dust and associated dry air that can interfere with hurricane formation.

"We'll be scrutinizing developing storms on many scales, from the invisible to the enormous," says Lance Bosart, a professor at the University at Albany-SUNY.

The airborne observations will be compared with data gathered from satellites as well as from ground-based radars in the Caribbean.

The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under sponsorship by the National Science Foundation. Any opinions, findings and conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

David Hosansky | Newswise Science News
Further information:
http://www.ucar.edu

More articles from Earth Sciences:

nachricht Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>