Line Islands Coring

PIs:  Jean Lynch-Stieglitz (GaTech), Pratigya Polissar (LDEO)

Cruise Dates: May 1 – 26, to and from Honolulu, Hawaii

Line Island, Equatorial Pacific Ocean
Description: ine Island Sites
The Line Islands Ridge in the Central Tropical Pacific.
A recently completed research expedition on the Lamont-Doherty Earth Observatory research vessel Marcus G. Langseth mapped and sampled sediments along the Line Islands in the central equatorial Pacific. The expedition, led by Jean Lynch-Stieglitz (Georgia Tech) and Pratigya Polissar (LDEO) recovered 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 collected several gravity and long piston cores, several CTD profiles with water samples and six multi-channel seismic surveys during their four weeks at sea.
•       41 Cores (Piston/Big Bertha Gravity, Multi-cores, small gravity cores) between 0-8°N across Line Islands ranging from ~2500-3800m.
•       Approximately 170m total recovery of sediment with large piston/gravity cores from 5-10m each.
•       Hi-Res Seismic- 2 priority sections shot with 2-GI guns and 900m streamer using Langseth MCS.
•       14 CTD’s collected with 24 bottle rosette.
For information on the results of this cruise, visit the cruise website here.
Blog: Future El Nino  
Description: TD Casting
CTD Casting JPEG