Marufish BLoG

Recent intensification of tropical climate variability in the Indian Ocean Nature Geoscience Published online: 16 November 2008 doi:10.1038/ngeo357 Nerilie J. Abram 1 , 2 , Michael K. Gagan 1 , Julia E. Cole 3 , Wahyoe S. Hantoro 4 & Manfred Mudelsee 5 The interplay of the El Niño Southern Oscillation, Asian monsoon and Indian Ocean Dipole (IOD) 1, 2, 3 drives climatic extremes in and around the Indian Ocean. Historical 4, 5 and proxy 6, 7, 8, 9 records reveal changes in the behaviour of the El Niño Southern Oscillation and the Asian monsoon over recent decades 10, 11, 12 . However, reliable instrumental records of the IOD cover only the past 50 years 1, 3 , and there is no consensus on long-term variability of the IOD or its possible response to greenhouse gas forcing 13 . Here we use a suite of coral oxygen-isotope records to reconstruct a basin-wide index of IOD behaviour since AD 1846. Our record reveals an increase in the frequency and strength of IOD events during the tw...

Coral study points to more harsh droughts BY NYSSA SKILTON 17/11/2008 8:52:00 AM, The Canberra Times New coral records have revealed Australia is likely to experience more frequent and intense droughts. Scientists studying the tropical weather patterns stored in corals have discovered climate variability in the Indian Ocean has intensified during the 20th century. This suggests Australia and the region can expect less rain while eastern Africa gets wetter. An international research team, led by the Australian National University, analysed corals from tropical waters north-east of Australia to build a picture of climate change going back to 1846. Their findings are published in the journal Nature Geoscience, available online today. To date, reliable records of the Indian Ocean Dipole a climate phenomenon similar to El Nino go back about 50 years. Palaeoclimatologist Mike Gagan, of the ANU's Research School of Earth Sciences, said the researchers' techniques allowed them to analy...

Droughts to become more frequent, severe: researchers ABC News, Mon Nov 17, 2008 Canberra scientists say they have proven that the world's climate is changing faster than ever before. The international research team drilled core samples from living corals off the Indonesian coast and found an increased frequency in the weather phenomenon known as the "Indian Ocean Dipole". Like the El Nino weather effect, the Indian Ocean Dipole has a dramatic impact on the Australian climate, and can cause severe droughts. Australian National University researcher Dr Mike Gagan says his coral samples show the dipole is occurring more regularly and that is changing Australian weather patterns. "There's going to be not only more propensity for drought, there's going to be more variability," he said. "If you get a dipole event superimposed onto an El Nino event, what may be a moderate El Nino event turns out to be a very strong drought." Dr Gagan says the Dipole ...