Wednesday, August 08, 2007

Perhaps the real clue to global warming

Sunspot Abundance Linked To Heavy Rains In East Africa

365,000 people hit by Sudan floods: UN
Khartoum (AFP) Aug 6 - Some 365,000 people have been hit by a month of flooding in Sudan, and the situation will only worsen as the rains continue, the United Nations humanitarian relief agency said on Monday. "Well over 30,000 houses were fully destroyed. At least 365,000 people have already been directly affected, including a reported 64 dead and 335 injured," the UN's Office for the Coordination of Humanitarian Affairs (OCHA) said in a statement. The UN's death toll is lower than one issued last month by the Sudanese government, which said that around 100 people had been killed in the floods as of July 18. Up to half a million people have received assistance from the UN and its partners in support of the Sudanese government, but more could be hit if the flooding continues, OCHA said. "Although the floods came earlier than expected, the response has been swift and successful. We had contingency measures in place, and were able to prevent further distress to the population," said David Gressly, the acting UN resident and humanitarian coordinator in Sudan. However, "if current flooding patterns continue unabated, the situation will deteriorate considerably," he warned. OCHA said it expects the rains to continue until at least mid-September. Around half a million people have received water purification products in a bid to stem the risk of water-borne diseases, although at least 39 people are already known to have died in the east of the country from acute watery diarrhoea, it said. Meanwhile, 200,000 people have received essential non-food items such as blankets, plastic sheeting to serve as shelter, jerry cans, cooking sets and sleeping mats, the agency said. "We are working closely with the government to reach accurate estimates of the needs of those affected, and of the funding requirements," said John Clarke, the UN official in charge of coordinating the response to the floods. (Please note - this current flood is note related to accompanying science report on rain and sunspots)

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 peak 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."

Original article posted here.

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