Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sunspot abundance linked to heavy rains in East Africa

06.08.2007
A new study reveals correlations between plentiful sunspots and periods of heavy rain in East Africa.

Intense rainfall in the region often leads to flooding and disease outbreaks.

The analysis by a team of U.S. and British researchers shows that unusually heavy rainfalls in East Africa over the past century preceded peak sunspot activity by about one year. Because periods of peak sunspot activity, known as solar maxima, are predictable, so too are the associated heavy rains that precede them, the researchers propose.

"With the help of these findings, we can now say when especially rainy seasons are likely to occur, several years in advance," says paleoclimatologist and study leader Curt Stager of Paul Smith's College in Paul Smiths, New York. Forewarned by such predictions, public health officials could ramp up prevention measures against insect-borne diseases long before epidemics begin, he adds.

The sunspot-rainfall analysis is scheduled to appear on 7 August in the Journal of Geophysical Research - Atmospheres, a publication of the American Geophysical Union.

Increasing sunspot numbers indicate a rise in the sun's energy output. Sunspot abundance peaks on an 11-year cycle. The next solar maximum is expected in 2011-2012. If the newfound pattern holds, rainfall would also peak the year before.

"We expect East Africa to experience a major intensification of rainy season precipitation, along with widespread Rift Valley Fever epidemics, a year or so before the solar maximum of 2011-2012," the team reports. Because mosquitoes and other disease-carrying insects thrive in wet conditions, heavy rains may herald outbreaks of diseases such as Rift Valley Fever.

The new analysis relies on rainfall data going back a century. The scientists also used historical records of water levels at lakes Victoria, Tanganyika, and Naivasha.

The work counters previous research that found no connection between sunspot cycles and rainfall in East Africa. Stager's team concludes that, although the link between sunspots and rainfall was weak between 1927 and 1968, the cyclic pattern held true throughout the 20th century. Previous statistical analysis discounted the link for a variety of reasons, including the influence of El Nino and other climatic disturbances not associated with sunspots.

Scientists have investigated apparent correlations between solar variability and Lake Victoria's water levels since the beginning of the last century, says co-author Alexander Ruzmaikin of NASA's Jet Propulsion Laboratory in Pasadena, California. The new research "shows that these correlations are, in fact, not accidental, effectively resolving a longstanding historical puzzle and improving our knowledge of how solar variability affects Africa's climate," he adds.

Stager, Ruzmaikin and their colleagues offer several reasons why sunspot peaks may affect rainfall. In a simple scenario, increased solar energy associated with sunspots heats both land and sea, forcing moist air to rise and triggering precipitation.

While sunspot peaks augur extraordinarily wet rainy seasons, heavy rains are possible at other times as well, Stager acknowledges. But, most of the rainiest times, he says, are consistently coupled with the predictable rhythms of sunspot peaks. And, to be forewarned is to be forearmed.

"The hope is that people on the ground will use this research to predict heavy rainfall events," Stager says. "Those events lead to erosion, flooding, and disease."

The National Science Foundation funded the study.

Peter Weiss | AGU
Further information:
http://www.agu.org

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

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>