Expeditions
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The Line Islands Ridge in the Central Tropical Pacific. |
An upcoming research expedition on the Lamont-Doherty Earth Observatory research vessel Marcus G. Langseth will map and sample sediments along the Line Islands in the central equatorial Pacific. The expedition, led by Jean Lynch-Stieglitz (Georgia Tech) and Pratigya Polissar (LDEO) will recover surface and long piston cores that will provide sediment material to study the past changes in the marine Intertropical Convergence Zone (ITCZ) as well as the behavior of El-Nino Southern Oscillation (ENSO). The atmospheric circulation in the tropics and subtropics, including the state of and the position of the ITCZ, determines the patterns of rainfall and drought that influence a vast number of people on the planet today. Unfortunately, our current understanding of these circulation patterns is not complete. The most sophisticated coupled ocean-atmosphere climate models still often differ from observations, for example persistently exhibiting a double ITCZ or failing to produce the proper magnitude and periodicity of modern ENSO variability.
The area of the central tropical Pacific targeted on this expedition is an ideal place to monitor the marine ITCZ, as it is far from the influence of the monsoons and other land-ocean linkages. Here, the ITCZ is well organized, largely confined to the Northern Hemisphere, and has less seasonal variation than in the Eastern and Western Pacific. This area is also ideally situated to monitor past ENSO activity, given that variability is dominated by inter-annual rather than seasonal variability. PI Polissar and his colleagues expect to collect 15 gravity and long piston cores, several CTD profiles with water samples and six multi-channel seismic surveys during their four weeks at sea.
For more information on this project contact Dr. Polissar at polissar@ldeo.columbia.edu.
Follow the Blog: Future El Nino here: http://www.ldeo.columbia.edu/research/blogs/future-el-nino
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CTD Casting |
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