Deep circulations in the ocean affect the distribution of physical, chemical, and biological properties, and are intimately entwined with the planetary-scale climate. Numerous proxies, including neodymium (Nd) in fossil fish teeth, point to a source region in the South Pacific for much of the low-latitude deep-water during the early Paleogene. We use the MIT general circulation model (MITgcm) to test the sensitivity of deep-water formation to uncertainty in surface boundary conditions in a number of numerical modeling experiments with realistic and idealized bathymetries. Finally, the MITgcm is run with a passive tracer, ENd , for some of the experiments mentioned above and to multiple initial surface distributions of ENd. In our experiments that use idealized basin shapes, appropriate for the early Cenozoic, the formation of North Pacific deep-water occurred in all of our experiments in which we vary the magnitude of the surface density gradient. While the rate of deep-water formation is sensitive to the strength of the surface density gradient, the location of the source regions was not. For our experiments that use realistic bathymetry, the formation of South Pacific deep-water occurred in a majority of our experiments. Here the Southern Ocean has the greatest poleward latitudinal extent, and therefore preference for deep-water formation. When salinity is added into the equation of state we find that this causes an increase in the extent of Southern Ocean deep-water. Lastly, we explore simulations using ENd as a passive tracer. Throughout most of the realistic simulations explored, the densest water occurs in the Southern Ocean. There is a strong sensitivity to where in the Southern Ocean the densest water occurs though, either in the South Pacific or Atlantic. With ENd values different in these regions, various simulations produced different tracer distributions. We found this variability in the sinking region to be very sensitive to runoff and seasonality. The sensitivity to the spatial distribution of surface and interior ENd values was found to have little affect on the final ENd distribution, given that the ENd value in the sinking regions was kept constant.

Thesis (doctoral)--Universiteit Utrecht, 2000. / Vita. Includes bibliographical references (leaves [179]-190). Also issued online.

Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, September 2008. / Thesis Advisor(s): Radko, Timour. "September 2008." Description based on title screen as viewed on November 4, 2008. Includes bibliographical references (p. 99-101). Also available in print.

Thesis (M.S. in Physical Oceanography)--Naval Postgraduate School, March 2009. / Thesis Advisor(s): Radko, Timour. "March 2009." Description based on title screen as viewed on April 23, 2009. Author(s) subject terms: Meridional overturning circulation, MOC, Antarctic Circumpolar Current, ACC, thermohaline circulation. Includes bibliographical references (p. 47-48). Also available in print.

Thesis (doctoral)--Universiteit Utrecht, 2000. / Vita. Includes bibliographical references (leaves [179]-190).

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2002. / "Joint Program in Oceanography/Applied Ocean Science and Engineering."--Cover. "June 2002." Funding was provided by the National Aeronautics and Space Administration under grant NAG5-7194, and by the Office of Naval Research under grant N00014-98-10881. Includes bibliographical references (p. 134-138).

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 144-158).

The dynamic response of the oceanic mixed-layer to the thermodynamic forcing at the sea surface is analyzed in order to describe the pattern of the oceanic meridional overturning. The technique proposed in this study is based on residual-mean theory, which takes into account the transport of buoyancy and tracers by transient eddies. From the observed air-sea density flux and mixed-layer density distributions, we estimate the two components of the Meridional Overturning Circulation (MOC) corresponding to the adiabatic (along-isopycnal) advection and the diabatic (cross-isopycnal) flux. Calculations are performed for the global ocean and, additionally, for each oceanic basin. The proposed method extends the Walin (1982) mass transformation theory, and permits, for the first time, assessment of the strength of the MOC adiabatic component from the sea surface data. This study offers a statistical description of the atmospheric and oceanic databases and gives some suggestions for the choice of specific datasets. In particular, the two most reliable atmospheric climatology databases (ECMWF and NCEP/NCAR re-analyses) are compared, and the impact of their inaccuracies on the MOC calculations is evaluated.

Thesis (doctoral)--Rijksuniversiteit te Utrecht, 1997. / Includes vita. Includes bibliographical references (p. [119]-124).

The primary seismic response mode of freestanding slender building contents is rocking. Rocking is one of the most damaging response modes due to large accelerations at impact and the possibility of toppling. This study investigates the rocking response of contents within fixed-base and base-isolated buildings so that better-informed decisions can be made, either at the design stage for new structures or during the performance evaluation for existing structures, to mitigate the effects of the destructive rocking behaviour and consequently minimize injury, economic loss, and downtime. A 3D model of a hospital building was created in OpenSees and analyzed to obtain floor accelerations for a suite of 20 broadband ground motions. These motions were then used as input to compute the rocking responses of many building contents. The rocking responses were compared and contrasted to determine the effect of the block’s size, slenderness, floor level, and placement within a level. The rocking response of contents in buildings isolated with lead plug and triple friction pendulum bearings were compared to the fixed-base building to determine the effectiveness of isolation as a means to control rocking. Fragility curves were also created for the fixed-base and isolated buildings. The vertical component of the floor accelerations had little effect on the rocking response of contents. The significance of this is that the location of an object on a given story does not affect its rocking response. However, higher vertical accelerations did increase the likelihood of the object lifting off the floor. The rocking response of stocky contents increased from one story to the next, but as the slenderness increased this transition became less evident. Base isolation was found to be effective at reducing both the likelihood to uplift and overturn. The longer period systems provided superior protection despite the long period pulse like motion while the damping of the systems had little effect on the rocking response. / Thesis / Master of Applied Science (MASc) / During an earthquake slender building contents respond by rocking about their edges. Rocking causes damage to sensitive and brittle objects as well as safety hazards if it results in the overturning of heavy objects. One goal of this study was to define the rocking response of rigid contents in a conventional braced frame hospital. In general, larger and stockier objects were less likely to overturn. Also, overturning was more prevalent higher up in the building while the location of an object within a given story had little effect. Another objective was to determine the effectiveness of base isolation, a technique that decouples the motion of the building from the ground using flexible bearings, as a strategy to protect contents that are vulnerable to rocking during an earthquake. This was found to be quite effective at reducing both the occurrence of uplift (the initiation of rocking) as well as toppling.