Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA working to take the guesswork out of long-term drought prediction

07.08.2003


Dr. Bob Oglesby, senior atmospheric scientist (NASA/MSFC/Doug Stoffer)


It´s tricky, this weather business — predicting drought, floods, rain or snow, especially months in advance. But NASA scientists at the National Space Science and Technology Center in Huntsville, Ala., are working to take the guesswork out of long-term prediction.

"We´re researching methods to predict precipitation a season or more in advance," said Dr. Bob Oglesby, a senior atmospheric scientist at the research center. The key, he said, is understanding how the atmosphere interacts with the land — sometimes in a way that completely alters the expected climate of a geographic area.

"The Gulf of Mexico, for example, is what keeps the Southeast from becoming semi-arid, or in the worst-case scenario, a big desert," he said, explaining that atmospheric flow sweeps primarily from west to east. Without the gulf, states like Alabama, Tennessee and Georgia would be forced to seek moisture from the Pacific Ocean. "But a series of mountain ranges blocks the way," he said. "If it weren´t for the nearby gulf, the lush, green landscapes of Southeast might more closely resemble the semi-arid landscapes of the great plains."



Just as mountain ranges can block moisture from an entire region, ridges of atmospheric pressure act as similar obstacles — blocking out much-needed moisture where conditions are dry, resulting in a "thermal mountain effect," first identified in 1953.

"Droughts are self-perpetuating," Oglesby said. "If an area is already experiencing drought conditions, it is more likely to continue in a drought. Similarly, if an area is experiencing extremely wet conditions, that trend is also likely to continue."

This self-perpetuating cycle is due to the interaction of moisture in the soil with the atmosphere. If the amount of rain or snowfall drops below average, the soil becomes dry. Then, as the Sun heats the Earth, less moisture is available for evaporation.

With the resulting reduction in evaporation — and its cooling effects — the surface of the Earth warms, heating the atmosphere. As the atmosphere´s temperature increases, air rises. This cycle reinforces the ridge of high pressure, enhancing its abilities to block the flow of moisture from bodies of water as well as reducing the likelihood of thunderstorm formation.

Drought conditions also may be predicted by studying other factors, including sea surface temperature variations such as those associated with ocean warming effects from El Niño, and ocean cooling effects from La Niña; north Atlantic oscillation, or air flow; and snow cover in surrounding regions.

Oglesby´s research uses computer models to simulate and predict weather conditions, using data such as soil moisture, precipitation and Earth´s surface temperature. The biggest challenge in making long-term predictions, he said, is a lack of sufficient data on soil moisture, especially moisture in lower layers of the soil.

"If someone could provide us with the state of soil moisture over a sufficiently large area, we can begin to predict its impact on precipitation over the next season or two," he said. Oglesby sees hope for better data in the future from NASA remote sensing technology that gleans information using satellite or flights over select areas.

Above-average rainfall or snow in the winter or spring can increase soil moisture to levels needed to help break the cycle of drought. But an average series of short, light rain showers — common in much of the South — are not generally enough, said Oglesby. "Even though surface soil may be wetted periodically, light rains may not drop enough moisture to reach lower soil areas. These perpetually dry areas, in turn, cause top soil to dry more quickly — once again hindering the Earth´s natural cooling process."

But there is hope even in the midst of drought conditions. "Even in a dry, Alabama summer, it rains," said Oglesby, noting that large-scale circulation and thunderstorms in the summer can also break the cycle of drought. "The trick," he said, "is replenishing the moisture in the soil before it´s too late."

From NASAs Marshall Space Flight Center in Huntsville, Oglesby has co-authored three research papers since 2001, published in the Journal of Climate and the Journal of Geophysical Research. Topics include diagnosing warm season precipitation, thresholds in atmosphere-soil moisture interactions and the predictability of winter snow cover over the Western United States.

Oglesby has a bachelors degree in physical geography from the University of California in Davis and a doctorate in atmospheric dynamics from Yale University in New Haven, Conn. He is based at the Global Hydrology and Climate Center, one of seven science research centers at the National Space Science and Technology Center, a partnership with NASAs Marshall Space Flight Center, Alabama universities, industry and federal agencies.

Contact: Steve Roy, steve.roy@msfc.nasa.gov

Steve Roy | NSSTC News
Further information:
http://www.msfc.nasa.gov/news

More articles from Earth Sciences:

nachricht Giant see-saw of monsoon rains detected
26.09.2016 | Potsdam-Institut für Klimafolgenforschung

nachricht A new 3D viewer for improved digital geoscience mapping
20.09.2016 | Uni Research

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Laser use for neurosurgery and biofabrication - LaserForum 2016 focuses on medical technology

27.09.2016 | Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

 
Latest News

New switch decides between genome repair and death of cells

27.09.2016 | Life Sciences

Nanotechnology for energy materials: Electrodes like leaf veins

27.09.2016 | Physics and Astronomy

‘Missing link’ found in the development of bioelectronic medicines

27.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>