Index Catalog // ScholarsArchive@OSU

Nitrogen isotopes in a global ocean biogeochemical model : constraints on the coupling between denitrification and nitrogen fixation

Creator:: Somes, Christopher J.
Abstract:: We present a new nitrogen isotope model incorporated into the three-dimensional ocean component of a global Earth System Climate Model designed for millennial timescale simulations. The model includes prognostic tracers for the stable nitrogen isotopes, ¹⁴N and ¹⁵N, in the nitrate (NO₃ˉ), phytoplankton, zooplankton, and detritus variables of the marine...
Resource Type:: Masters Thesis
Full Text:: : Andreas Schmittner We present a new nitrogen isotope model incorporated into the three-dimensional

Glacial greenhouse-gas fluctuations controlled by ocean circulation changes

Creator:: Schmittner, Andreas and Galbraith, Eric D.
Abstract:: Earth's climate and the concentrations of the atmospheric greenhouse gases carbon dioxide (CO2) and nitrous oxide (N2O) varied strongly on millennial timescales during past glacial periods. Large and rapid warming events in Greenland and the North Atlantic were followed by more gradual cooling, and are highly correlated with fluctuations of...
Resource Type:: Article
Full Text:: controlled by ocean circulation changes Andreas Schmittner1 & Eric D. Galbraith2 Earth’s climate and the

Model projections of the North Atlantic thermohaline circulation for the 21st century assessed by observations

Creator:: Schmittner, Andreas, Latif, M., and Schneider, B.
Abstract:: Most climate models predict a weakening of the North Atlantic thermohaline circulation for the 21st century when forced by increasing levels of greenhouse gas concentrations. The model spread, however, is rather large, even when the forcing scenario is identical, indicating a large uncertainty in the response to forcing. In order...
Resource Type:: Article
Full Text:: thermohaline circulation for the 21st century assessed by observations A. Schmittner,1 M. Latif,2 and B

Paleoclimate, paleoventilation, and paleomagnetism as recorded in a 17kyr marine sediment record from the SE Alaska margin

Creator:: Davies, Maureen Helen
Abstract:: The deglacial behavior of the sub-Arctic North Pacific is poorly constrained, with many published records suffering from limited age control due to extensive post- depositional biogenic carbonate dissolution. Potential alternative dating methods could include the correlation of stable-isotopic and/or paleomagnetic secular variation records to an independently-dated regional template, however no...
Resource Type:: Dissertation
Full Text:: thoughtful input and oversight of my committee members: Andreas Schmittner, Nick Pisias, Ed Brook, and

Nitrogen isotope simulations show the importance of atmospheric iron deposition for nitrogen fixation across the Pacific Ocean

Creator:: Somes, Christopher J., Schmittner, Andreas, and Altabet, Mark A.
Abstract:: Nitrogen (N) fixation by specialized microorganisms (diazotrophs) influences global plankton productivity because it provides the ocean with most of its bio-available N. However, its global rate and large-scale spatial distribution is still regarded with considerable uncertainty. Here we use a global ocean nitrogen isotope model, in comparison with δ15NO3 observations,...
Resource Type:: Article
Full Text:: . Somes,1 Andreas Schmittner,1 and Mark A. Altabet2 4 Received 1 July 2010; revised 8 September 2010

Large fluctuations of dissolved oxygen in the Indian and Pacific oceans during Dansgaard-Oeschger oscillations caused by variations of North Atlantic Deep Water Subduction: Paleoceanography

Creator:: Schmittner, Andreas, Galbraith, Eric D., Hostetler, Steven W., Pedersen, Thomas F., and Zhang, Rong
Abstract:: Paleoclimate records from glacial Indian and Pacific oceans sediments document millennial-scale fluctuations of subsurface dissolved oxygen levels and denitrification coherent with North Atlantic temperature oscillations. Yet the mechanism of this teleconnection between the remote ocean basins remains elusive. Here we present model simulations of the oxygen and nitrogen cycles that...
Resource Type:: Article
Full Text:: Atlantic Deep Water subduction 5 Andreas Schmittner,1 Eric D. Galbraith,2,3 Steven W. Hostetler,4,5 Thomas

What is the skill of ocean tracers in reducing uncertainties about ocean diapycnal mixing and projections of the Atlantic Meridional Overturning Circulation?

Creator:: Schmittner, Andreas, Tonkonojenkov, Roman, Urban, Nathan M., Goes, Marlos, Haran, Murali, and Keller, Klaus
Abstract:: Current projections of the oceanic response to anthropogenic climate forcings are uncertain. Two key sources of these uncertainties are (1) structural errors in current Earth system models and (2) imperfect knowledge of model parameters. Ocean tracer observations have the potential to reduce these uncertainties. Previous studies typically consider each tracer...
Resource Type:: Article
Full Text:: Circulation? 4 Marlos Goes,1 Nathan M. Urban,1 Roman Tonkonojenkov,1 Murali Haran,2 5 Andreas Schmittner,3

What is the skill of ocean tracers in reducing uncertainties about ocean diapycnal mixing and projections of the Atlantic Meridional Overturning Circulation?

Creator:: Goes, Marlos, Urban, Nathan M., Tonkonojenkov, Roman, Haran, Murali, Schmittner, Andreas, and Keller, Klaus
Abstract:: Current projections of the oceanic response to anthropogenic climate forcings are uncertain. Two key sources of these uncertainties are (1) structural errors in current Earth system models and (2) imperfect knowledge of model parameters. Ocean tracer observations have the potential to reduce these uncertainties. Previous studies typically consider each tracer...
Resource Type:: Article
Full Text:: Circulation? 4 Marlos Goes,1 Nathan M. Urban,1 Roman Tonkonojenkov,1 Murali Haran,2 5 Andreas Schmittner,3

Changes in equatorial Pacific thermocline depth in response to Panamanian seaway closure: Insights from a multi-model study

Creator:: Zhang, Xiao, Prange, Matthias, Steph, Silke, Butzin, Martin, Krebs, Uta, Lunt, Daniel J., Nisancioglu, Kerim H., Park, Wonsun, Schmittner, Andreas, Schneider, Birgit, and Schulz, Michael
Abstract:: The early Pliocene warm phase was characterized by high sea surface temperatures and a deep thermocline in the eastern equatorial Pacific. A new hypothesis suggests that the progressive closure of the Panamanian seaway contributed substantially to the termination of this zonally symmetric state in the equatorial Pacific. According to this...
Resource Type:: Article

Modern and past climate variability in the eastern Pacific warm pool

Creator:: Benway, Heather M.
Abstract:: Westward transport of water vapor across the Panama Isthmus helps to maintain the salinity contrast between the Atlantic and Pacific Oceans, important in thermohaline circulation and global climate. Relatively low sea-surface salinities and a strong, shallow pycnocline in the eastern Pacific warm pool (EPWP) region near Central America reflect high...
Resource Type:: Dissertation
Full Text:: Kelly Falkner. Andreas Schmittner provided very insightful comments on Chapter 4. I thank Joe Stoner

ScholarsArchive@OSU

Nitrogen isotopes in a global ocean biogeochemical model : constraints on the coupling between denitrification and nitrogen fixation

Glacial greenhouse-gas fluctuations controlled by ocean circulation changes

Model projections of the North Atlantic thermohaline circulation for the 21st century assessed by observations

Paleoclimate, paleoventilation, and paleomagnetism as recorded in a 17kyr marine sediment record from the SE Alaska margin

Nitrogen isotope simulations show the importance of atmospheric iron deposition for nitrogen fixation across the Pacific Ocean

Large fluctuations of dissolved oxygen in the Indian and Pacific oceans during Dansgaard-Oeschger oscillations caused by variations of North Atlantic Deep Water Subduction: Paleoceanography

What is the skill of ocean tracers in reducing uncertainties about ocean diapycnal mixing and projections of the Atlantic Meridional Overturning Circulation?

What is the skill of ocean tracers in reducing uncertainties about ocean diapycnal mixing and projections of the Atlantic Meridional Overturning Circulation?

Changes in equatorial Pacific thermocline depth in response to Panamanian seaway closure: Insights from a multi-model study

Modern and past climate variability in the eastern Pacific warm pool

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