Science Team Recovers Key Information on Global Climate History
Expedition 346 (Asian Monsoon), the final expedition of the Integrated Ocean Drilling Program, officially concluded when the JOIDES Resolution entered port in Busan, South Korea on September 27, 2013. The team drilled more than six kilometers of core samples in just six weeks of on-site operations (following a two-week transit from Valdez, Alaska), and set a new record for the deepest continuous piston core sequence ever recovered, reaching to 490 meters below the seafloor.
Led by co-chief scientists Ryuji Tada (University of Tokyo) and Rick Murray (Boston University), the expedition visited seven sites in the Japan Sea/East Sea and one site in the northern East China Sea. Preliminary findings suggest that the team retrieved an unparalleled record of climate cyclicity in the Miocene epoch (from about 23 to 5 million years ago), documented a consistent regional response to climate change in the Japan Sea/East Sea, and observed climate signals consistent with those found elsewhere in the world, such as ice cores from Greenland.
“The result will also reveal how climatic changes in the continent, together with sea level changes, affect oceanic conditions in marginal seas,” Tada says. “Obviously terrestrial climate and sea level impacted nutrient and carbon cycles in the Japan Sea/East Sea, which could have been significant on a global scale.”
The East Asian monsoon is a significant force in global weather and climate, affecting nearly a third of the world’s population in Japan, North and South Korea, much of eastern China, and beyond. It has two phases: a warm, wet summer monsoon and a cool, dry winter monsoon. Often, the timing of the monsoon cycle is predictable. But many factors – including complex interactions between the ocean and land – have an influence on the system and can cause variability. Discovering more about these interrelationships should help scientists better predict how the monsoon will react to climate change and other factors in the future.
“Over the next 100 years, due to climate change it is likely that the monsoon system will change,” Murray says. “Some areas will get drier, and some wetter. By looking at the natural system—how rapidly it changes and under what conditions—we can get a sense of what the likely scale of future changes will be.”
A primary goal is to test the hypothesis that the most recent uplift of the Himalaya mountain range and the Tibetan Plateau, beginning about 3.5 million years ago, is responsible for the variability of East Asian monsoon patterns. By reading the signals recorded in the sediments here, the science team should be able to discern changes in patterns of rainfall and sediment discharge from on land, as well as changes in oceanographic processes such as surface water circulation and deep-water convection.
The Integrated Ocean Drilling Program (IODP) is an international research program dedicated to advancing scientific understanding of the Earth through drilling, coring, and monitoring the subseafloor. The JOIDES Resolution is a scientific research vessel managed by the U.S. Implementing Organization of IODP (USIO). Together, Texas A&M University, Lamont-Doherty Earth Observatory of Columbia University, and the Consortium for Ocean Leadership compose the USIO. IODP is supported by two lead agencies: the U.S. National Science Foundation (NSF) and Japan’s Ministry of Education, Culture, Sports, Science, and Technology. Additional program support comes from the European Consortium for Ocean Research Drilling (ECORD), the Australia-New Zealand IODP Consortium (ANZIC), India’s Ministry of Earth Sciences, the People’s Republic of China (Ministry of Science and Technology), the Korea Institute of Geoscience and Mineral Resources, and Brazil’s Ministry of Education (CAPES). For more information, visit www.iodp.org.
For more information about IODP Expedition 346 (Asian Monsoon), visit http://iodp.tamu.edu/scienceops/expeditions/asian_monsoon.html
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Washington, D.C. USA