Read the blog for the cruise that Whitney is on
Course description: A yearly investigation, in seminar format, of major problems in the study and understanding of Quaternary climate variation. Each year one or two major topics will be addressed, which may include: the physics and chemistry of the glacial ocean circulation; the theory and mechanics of glacial/interglacial atmospheric CO2 change; the origins of the 20, 40, and 100 kyr (Milankovitch) climate cycles; and resolving tropical climates during the last glacial maximum.
In Spring ’10, we will focus on the physics and chemistry of the glacial ocean circulation.
Expectations and grading: Students will be required to make presentations on assigned readings from both the historic and current research literature. There will be one or two discussion leaders per week, but everyone is responsible for reading the papers and participating in the discussion. Presentations should go beyond the papers at hand by providing relevant background material (including figures) that helps to place the papers in the context of previous studies. We are not looking for an exhaustive summary of the reading, but rather a framework from which the group can discuss and better understand the papers. In addition, each week one student will be assigned the role of "web gopher," and may be asked during class to retreive particular papers from the internet. Grades will be based on the quality of presentations (40%) and on overall participation, which includes attendance (60%).
Readings will be available either as online pdfs or as hardcopies on reserve in the INSTAAR Reading Room and the Geological Sciences Library.
Meets: Mondays 10 am - 12 pm, Mort Turner Room, INSTAAR (RL1 233)
Instructors: Scott Lehman, scott.lehman@colorado.edu;
Tom Marchitto, tom.marchitto@colorado.edu
Office Hours: By appointment
Credits: 2
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Week 1 (W 1/13, 3 pm, INSTAAR RL1 233): Organizational meeting
Week 2 (1/18): No Class (MLK Day)
Week 3 (1/25): Modern ocean circulation (instructor presentations by Tom and Scott) and Early thinking about the glacial circulation
Required Reading: Weyl, The role of the ocean in climatic change: A theory of the ice ages, Meteorological Monographs, 8(30): 37-62, 1968. hardcopy also on reserve (Katie)
Week 4 (2/1): Carbon-13 as a deep water tracer
Required Reading: Kroopnick, The distribution of 13C of TCO2 in the world oceans, Deep Sea Research, 32(1): 57-84, 1985 (Ursula)
Required Reading: Curry et al., Changes in the Distribution of d13C of Deep Water TCO2 Between the Last Glaciation and the Holocene, Paleoceanography, 3(3): 317-341, 1988. (Mariah)
This paper is not required but is a good complement to Curry et al., and includes a useful visualization of the LGM Atlantic d13C: Duplessy et al., Deepwater source variations during the last climatic cycle and their impact on the global deepwater circulation, Paleoceanography, 3(3): 343-360, 1988.
This paper is not required but summarizes the current state of the art for the LGM Atlantic d13C: Curry and Oppo, Glacial water mass geometry and the distribution of d13C of TCO2 in the western Atlantic Ocean, Paleoceanography, 20: PA1017, doi:10.1029/2004PA001021, 2005.
Week 5 (2/8): Comparing Cd/Ca and d13C
Required Reading: Boyle, Cadmium and d13C paleochemical ocean distributions during the stage 2 glacial maximum, Annu. Rev. Earth Planet. Sci., 20: 245–287, 1992. (Pam)
Required Reading: Rosenthal et al., Last Glacial Maximum Paleochemistry and Deepwater Circulation in the Southern Ocean: Evidence From Foraminiferal Cadmium, Paleoceanography, 12(6): 787-796, 1997. (Andrew)
This paper is not required but summarizes the current state of the art for the LGM Atlantic Cd/Ca: Marchitto and Broecker, Deep water mass geometry in the glacial Atlantic Ocean: A review of constraints from the paleonutrient proxy Cd/Ca, Geochemistry, Geophysics, Geosystems, 7(12), Q12003, doi:10.1029/2006GC001323, 2006.
Week 6 (2/15): Air-sea d13C
Required Reading: Broecker and Maier-Reimer, The Influence of Air and Sea Exchange on the Carbon Isotope Distribution in the Sea, Global Biogeochemical Cycles, 6(3): 315-320, 1992. (Kate)
Required Reading: Lynch-Stieglitz et al., The Influence of Air-Sea Exchange on the Isotopic Composition of Oceanic Carbon: Observations and Modeling, Global Biogeochemical Cycles, 9(4): 653-665, 1995. (Colin)
This paper is not required but illustrates an early attempt to reconstruct d13Cas for the LGM world ocean: Lynch-Stieglitz and Fairbanks, A conservative tracer for glacial ocean circulation from carbon isotope and palaeo-nutrient measurements in benthic foraminifera, Nature, 369: 308-310, 1994.
Also see Marchitto and Broecker (2006) section 5.2 for a more recent discussion of d13Cas in the LGM Atlantic.
Week 7 (2/22): Deep Pacific
Required Reading: Matsumoto et al., Interior hydrography and circulation of the glacial Pacific Ocean, Quaternary Science Reviews, 21: 1693-1704, 2002. (Katie)
Required Reading: McCave et al., Glacial–interglacial changes in water mass structure and flow in the SW Pacific Ocean, Quaternary Science Reviews, 27: 1886-1908, 2008. (Caroline)
Week 8 (3/1): Pa/Th kinematic tracer
Required Reading: Yu et al., Similar rates of modern and last-glacial ocean thermohaline circulation inferred from radiochemical data, Nature, 379: 689-694, 1996 (Whitney)
Required Reading: Gherardi et al., Glacial-interglacial circulation changes inferred from 231Pa/230Th sedimentary record in the North Atlantic region, Paleoceanography, 24: PA2204, doi:10.1029/2008PA001696, 2009. (Ursula)
Week 9 (3/8): Constraints from radiocarbon
Required Reading: Matsumoto and Key, Natural Radiocarbon Distribution in the Deep Ocean, in: Global Environmental Change in the Ocean and on Land, Eds., M. Shiyomi et al., pp. 45–58, 2004. (Colin)
Required Reading: Butzin et al., Radiocarbon simulations for the glacial ocean: The effects of wind stress, Southern Ocean sea ice and Heinrich events, Earth and Planetary Science Letters, 235: 45-61, 2005. (Katie)
Week 10 (3/15): Paleo-geostrophy
Required Reading: Lynch-Stieglitz et al., Weaker Gulf Stream in the Florida Straits during the Last Glacial Maximum, Nature, 402: 644-648, 1999. (Andrew)
Required Reading: Lynch-Stieglitz et al., Meridional overturning circulation in the South Atlantic at the last glacial maximum, G-Cubed, 7: Q10N03, doi:10.1029/2005GC001226, 2006. (Caroline)
Week 11 (3/22): No Class (Spring Break)
Week 12 (3/29): Numerical models I
Required Reading: Manabe and Stouffer, Two stable equilibria of a coupled ocean-atmosphere model, Journal of Climate, 1: 841-866, 1988. (Whitney)
Week 13 (4/5): Numerical models II
Required Reading: Ganopolski et al., Simulation of modern and glacial climates with a coupled global model of intermediate complexity, Nature, 391: 351-356, 1998. (Mariah)
Required Reading: de Boer et al., Effect of global ocean temperature change on deep ocean ventilation, Paleoceanography, 22: PA2210, doi:10.1029/2005PA001242, 2007. (Kate)
Week 14 (4/12): Southern Ocean dynamics
Required Reading: Toggweiler and Samuels, Effect of drake passage on the global thermohaline circulation, Deep Sea Research I, 42: 477-500, 1995. (Pam)
Required Reading: Keeling and Stephens, Antarctic sea ice and the control of Pleistocene climate instability, Paleoceanography, 16: 112-131, 2001. which also has a Correction. (Mariah)
Week 15 (4/19): Deep sea T/S (the Adkins Blob)
Required Reading: Adkins et al., The Salinity, Temperature, and d18O of the Glacial Deep Ocean, Science, 298: 1769-1773, 2002. (Whitney)
Required Reading: Otto-Bliesner et al., Last Glacial Maximum ocean thermohaline circulation: PMIP2 model intercomparisons and data constraints, Geophysical Research Letters, 34: L12706, doi:10.1029/200GL029475, 2007. (Caroline)
Week 16 (4/26): Subtropical gyre circulation and Course Wrap-up
Required Reading: Slowey and Curry, Glacial-Interglacial Differences in Circulation and Carbon Cycling Within the Upper Western North Atlantic, Paleoceanography, 10: 715-732, 1995.