An international research team will study the climate system of the southeastern Pacific ocean from next month (January).
The programme, VOCALS, aims to better understand El Niño - the complex climate phenomenon that impacts Latin America and other continents in the Southern Hemisphere - and whether it will be affected by climate change.
The periodic reversal of currents in the Pacific Ocean, known as the El Niño-Southern Oscillation (ENSO), is characterised by variations in the surface temperature of waters in the eastern Pacific, causing floods and droughts in western Latin America.
The research team for the 3-5 year, US$16 million programme includes 150 scientists from nine countries. The major groups are from universities of Chile, Ecuador, France, Peru, the United Kingdom and the United States.
Roberto Mechoso, professor in the department of atmospheric and oceanic sciences at the University of California Los Angeles, and chair of the programme, says that obtaining new information is crucial to solve errors in current climate models.
"Is El Niño going to be stronger or weaker if the climate warms up? Our confidence in model predictions of that impact will increase if the models produce a more realistic portrayal of the current climate," says Mechoso.
Groups from the Latin American region contribute their unique knowledge of the local meteorology and oceanography, says Mechoso.
"Other groups provide the expertise and instrumentation to set the problem in a more global domain; all groups win in the exchange of scientific knowledge," he told SciDev.Net.
Rene Garreaud, professor in the department of geophysics at the University of Chile and VOCALS team member, told SciDev.Net that ENSO's effects on annual modifications of temperature and precipitations vary significantly in different areas of Latin America.
The research programme will also try to understand the dynamics of cloud formation and the effects of aerosols, and use that information to improve climate prediction models.
Meanwhile, T. V. Padma writes from New Delhi (India), Scientists have solved the riddle of why some El Niño events cause the Indian monsoon to fail while others do not, which may lead to more accurate forecasts of drought.
The extremes of weather associated with El Niño are caused by the periodic warming of the surface of the Pacific Ocean.
Severe droughts in India have always occurred in El Niño years, yet every El Niño does not cause monsoon failure and drought - a mystery that researchers have been struggling to crack.
Accurate monsoon prediction is crucial to India's economy: nearly one-fifth of the country's gross domestic product comes from agriculture. Even moderate crop failures have severe economic and societal impacts.
Research published online by Science today (7 September) shows that it depends on whether the surface of the equatorial Pacific Ocean is warmest in the east, along Latin America, or closer to the centre.
Martin Hoerling of the National Oceanic and Atmospheric Administration Earth System Research Laboratory in Boulder, United States, and his colleagues say India is more prone to drought when the warm Pacific temperatures typical of El Niño extend westwards into the central Pacific Ocean.
The team analysed 23 strong El Niño years and their links to 13 droughts and 10 drought-free years in India, using satellite observations of sea surface temperatures and historical data of rainfall over central India.
Having found that drought was associated with warm water in the central Pacific, they used computer models to mimic the patterns, which confirmed their findings.
The researchers suggest that the "two flavours of El Niño" might affect the Indian monsoon differently through the tropical Walker circulation - an east-west wind over the Pacific.
The scientists say their research does not rule out the possibility that other factors, such as Indian ocean temperatures, also play a role.
And changes in ocean temperatures brought about by human-induced climate change could also affect the intensity of the Indian monsoon, they add.
The ability to predict monsoon rainfall over Asia, and the impact of global warming on this rainfall, is poor.
There has been no improvement in five-day forecasting in India in many years; the India Meteorological Department still uses a method devised in the early twentieth century.
Modern forecasts should be based on measurements of sea surface temperature, soil moisture and snow cover, but there are currently no adequate climate models to do this accurately.
For the sake of farmers and water managers, the research community must develop models that can predict fluctuations in rainfall over different regions of India within seasons, not just between seasons, and also in a changing climate, writes Jagadish Shukla in this Science article.
Such models will influence climate change adaptation and mitigation strategies for all countries affected by the Asian summer monsoon.
Another report says, Andean glaciers are "ultra-sensitive" indicators of climate change, capable of recording variations that occur even within a decade, says a team of Ecuadorian and French researchers.
Bernard Francou, of the French Institute of Research for Development, and colleagues spent eight years documenting the relationship between the El Niño - Southern Oscillation (ENSO) - a periodic warming and cooling of the Pacific Ocean and associated changes in air pressure - and the erosion of glaciers in Ecuador.
Their results, published this month in the Journal of Geophysical Research, indicate that there is a tight and quantifiable link between ENSO events and the accelerated melting of the Andean glaciers.
Neil Glasser, of the University of Aberystwyth, United Kingdom, says the findings themselves are unsurprising and confirm a previous 'hunch' held by glaciologists.
More importantly, he says, the researchers' "huge effort" in maintaining an eight-year monitoring programme in a difficult environment suggests that past El Niño events could be precisely read in Andean ice cores.
Since understanding past climate change is essential to predicting future events, this could be an invaluable tool. Currently, data on past El Niño events has come from meteorological measurements and records of sea-surface temperatures. But data recorded this way covers only the past few decades.
The sort of data that could be extracted from ice cores, however, would provide information on events that happened from a century ago up to the present day.
Francou agrees with Glasser on this point, but cautions that this will require more research, as 'reading' the indicators in high-altitude ice cores can be very complex.
In the short term, says Glasser, the melting of the glaciers could be seen as good news for the communities living on the slopes beneath them who rely of melting ice for water supplies. In the long term, however, it means that their water supply will gradually dry up as the glaciers are melting faster than the ice is reforming.
Commenting on the value of Francou's team's measurements, Glasser said they would help predict the future rate of run-off from the glaciers. This could in turn help communities plan their water usage.
http://nation.ittefaq.com/issues/2007/12/28/news0825.htm
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