Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 17). / Consistent data demonstrates a rise in global atmospheric concentrations of carbon, in the form of carbon dioxide. A large portion of the current atmospheric concentration is due to emissions from the burning of fossil fuels, which humans use for energy consumption. Many experts believe that of all the mechanisms in which carbon dioxide emissions can be mitigated, sequestering carbon dioxide, specifically in geologic reservoirs, is among the most promising of all approaches. This paper examines a fault structure in the specific geologic reservoir known as NPR-3, or the Teapot Dome oilfield. Using seismic modeling and subsurface modeling software packages to interpret seismic data of the region, geologic features and faults are mapped. These maps provide valuable characterization information useful to an overall evaluation of the effectiveness of geological storage of carbon sequestration in the Teapot Dome site. / by Melanie J. Michalak. / S.B.

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages [32]-[34]). / This paper characterizes the compositionally distinctive high-Na andesite lavas at Medicine Lake Volcano that erupted at ~100 ka and that built most of Medicine Lake's caldera. These high-Na lavas define a compositional trend that formed by fractional crystallization in a shallow magma chamber (~ 4 to 8 km). Petrologic evidence indicates pre-eruptive H20 contents of 2 to 4 wt.% H20 over a temperature range of 1070 to 900 C. Oxygen fugacity recorded in coexisting spinel and rhombohedral oxides varies from NNO (Nickel - Nickel Oxide) to NNO 0.7 log units. Experiments performed at 1 kbar - H20 saturated conditions at the NNO buffer on a primitive andesite reproduce most of the major element compositional variability exhibited in the high-Na lavas. / by Jocelyn J. Fuentes. / S.B.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2004. / Includes bibliographical references (leaves 28-29). / Certain mixed bedrock/alluvial channels located in the Valley and Ridge province of the Appalachians in Virginia were identified as having a pattern of systematic oversteepening of channel gradients at tributary junctions. Where drainage area increased, channel slopes were either increasing or remaining constant. Subsequent investigation of 10m resolution digital elevation models found this pattern to be widespread throughout several large nearby drainage basins (A [approximately] 10⁸m²). Several hypotheses for the causes and constraints of the pattern were tested in two ways: (1) digital profiles were compared to pre-existing data sets for grain-size, channel width, lithology, and drainage area; (2) a short field venture was conducted to test the accuracy of the DEMs and to provide additional data sets such as grain-size and channel width against which to compare the digital longitudinal profiles. Results show that there is some correlation between lithology, drainage area, and a pattern of downstream fining. However, the relationships are not strong and begs an analysis of the region at large to explain this channel gradient phenomenon. Periodically high levels of sediment flux moving through the drainage system, eg. debris flows, are a promising mechanism for the initiation of systematic oversteepening in the longitudinal profiles. / by Leah M. Windhorst. / S.M.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, February 2017. / Cataloged from PDF version of thesis. "February 2017." / Includes bibliographical references. / This dissertation uses high-precision U-Pb zircon geochronology to document the spatial and temporal distribution of magmatism, deformation, and sedimentation during Paleogene ridge-trench interaction in western Washington. Chapter 1 creates a regional stratigraphy for nonmarine sedimentary and volcanic rocks throughout central and western Washington and demonstrates that the depositional history of these rocks is consistent with accretion of over thickened oceanic crust (Siletzia terrane) and passage of a triple-junction. Chapter 2 establishes the volcanic stratigraphy of northern Siletzia and show that it is consistent with its origin as an accreted oceanic plateau, possibly developed above a long-lived Yellowstone hot spot. Chapter 3 quantifies magma emplacement rates in a large, granitoid intrusive complex (Golden Horn batholith) that was emplaced during Paleogene ridge-trench interaction. Parts of this batholith were constructed at the highest rate ever documented in a large granitoid intrusive complex (~0.0125 km³/a). This high emplacement rate may be related to its unique tectonic setting. The second tectonic setting is the rift-to-drift transition in the Newfoundland-Iberia rift. This rift is considered the type example of a magma-poor rifted margin and both margins consist of broad areas of exhumed subcontinental lithospheric mantle. Chapter 5 documents time-transgressive magmatism from east to west across both margins and suggests that mantle was exhumed during a single period of detachment faulting. / by Michael Patterson Eddy. / Ph. D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2000. / Includes bibliographical references (leaves 35-36). / Solar insolation at the poles is the driving force in Mars' seasonal climatic cycle. Mars' obliquity has varied greatly in the geologically recent past and this would have had a profound effect on the past climate. Previous studies have always assumed a spherical planet when calculating insolation. This study uses a geodetic elevation model (GEM) of the elevation data from the Mars Orbiter Laser Altimeter, to provide accurate insolation calculations. This method takes into account the long and shortwavelength topography, the planetary curvature, and the planetary flattening. This paper outlines the design and implementation of a GEM, and presents insolation calculations for Mar's north polar cap for obliquities of 150, 250 and 450. This study found that the elevation of the northern ice cap above the surroundings results in the ice cap having more days of sunlight than previously thought. / by Russell Arrell. / S.M.

Thesis: Ph. D. in Climate Science, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 169-183). / Patterns of tropical precipitation are sensitive to the atmosphere's energy balance and shift, for example, into the hemisphere heated most strongly by radiation and surface heat fluxes. By redistributing heat around the globe, the ocean circulation plays an important role in the atmosphere's energy balance and is a potentially strong control on the region of intense tropical rainfall known as the intertropical convergence zone, or ITCZ. This thesis explores several aspects of the coupling of the ocean's heat transport to the ITCZ and atmospheric circulation. First, I study connections between Atlantic Ocean heat transport variability and the position of the ITCZ in the 20th Century. Using atmospheric reanalyses and reconstructions of tropical precipitation, I find correlations between sea surface temperatures in the North Atlantic, the ITCZ position, and tropospheric temperatures that are consistent with Atlantic Ocean-forced ITCZ shifts. The rest of the thesis focuses on aspects of the coupling of the ocean's subtropical cells (STCs) to the ITCZ and the atmosphere's Hadley cells. By forcing an idealized atmosphere-ocean global climate model with an inter-hemispheric heating contrast, I find the STCs act to strongly damp the resulting ITCZ shift through their cross-equatorial heat transport, which partially compensates the imposed heating contrast. Coupled to the Hadley cells and ITCZ by the trade winds, heat transport by the STCs always acts to weaken ITCZ shifts and is a powerful control on the ITCZ position, keeping it "stuck" to latitudes near the equator. Applying the results from the idealized experiments, I estimate the STCs act to damp ITCZ shifts on Earth by a factor of two. In the case of a hemispherically symmetric climate with the ITCZ on the equator, I study the influence of the STCs on the strength of the Hadley cells by performing a range of global warming and cooling experiments on the same idealized model. Compared to the case without any ocean heat transport, the STCs act to strongly weaken the Hadley cells, particularly in cold climates, by reducing the meridional heating contrast across the cells. Using a new energy balance framework to quantify this cross-cell heating contrast, I show that part of the impact of the STCs' poleward heat transport is offset by anomalous equatorward energy transport by atmospheric eddies. My results suggest the STCs act to weaken the Hadley cells further than previously thought. / by Brian Marcus Green. / Ph. D. in Climate Science

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2011. / Cataloged from PDF version of thesis. Page 46 blank. / Includes bibliographical references (p. 41-45). / Striking geological features on Mercury's surface have been linked to tectonic disruption associated with the Caloris impact and have the potential to provide information on the interior structure of Mercury. The unusual disrupted terrain located directly at the antipode of the 1500-km-diameter Caloris basin could have plausibly formed as a consequence of focused seismic waves generated by the massive impact event. In this paper, we revisit the antipodal seismic focusing effects of the Caloris impact by developing physically consistent structure models for Mercury and parameterized seismic source models for the Caloris impact. If the focused seismic body waves caused the disrupted terrain, then the amplitudes of the waves and the areal extent of surface disruptions could be used for estimating the seismic energy imparted by the impact. In this study, we show that effects of direct body waves are small relative to those of the focused guided waves. Two types of guided waves are generated by the Caloris impact. One is the conventional Rayleigh wave generated by the impact. The second is the mantle guided waves trapped between the core and the free surface. Mantle guided waves, not mentioned in previous studies, may have played an important role in the creation of the disrupted terrain. We find that the early core state has only moderate effects on the antipodal response to the Caloris impact. The fact that the zone of predicted disruption for both fluid and solid core cases is smaller than the observed region of chaotic terrain suggests either that the antipodal response to the Caloris impact may have been modulated by the shallow structure of Mercury, or that the energy imparted by the impact was larger than those used in this study. / by Jiangning Lü. / S.M.

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2017. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 11-12). / Atmospheric aerosols have an important role in cloud formation and, by extension, in the overall climate system. Field studies are required to refine the uncertainty associated with the net radiative effect of atmospheric aerosols. Two pre-existing cloud sampling devices, the pumped counterflow virtual impactor (PCVI) and aerodynamic lens concentrator (ADL), were modelled using computer aided design software and printed using stereolithography printing. These devices were compared against their industrial counterparts. The printed PCVI was proven to be as effective as the industrial PCVI in a smaller working range. The printed concentrator effectively concentrated particles, but at a lower concentration factor than the industrial concentrator. This study revealed potential for further refinement in design features for both devices and it served as an essential pre-study for future field campaigns that will use these 3D printed devices. / by Libby Koolik. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1993. / Includes bibliographical references. / by Carol Arnosti. / Ph.D.

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 62-63). / In some experiments in which idealized general circulation models (GCMS) are used to study the tropospheric response to stratospheric perturbations, the tropospheric response is much stronger and longer-lived compared to observations (e.g., Polvani and Kushner 2002, Kushner and Polvani 2004). Chan and Plumb (2009) found that those experiments which exhibited particularly long tropospheric decorrelation times (and, by the fluctuation dissipation theorem, much stronger annular mode responses) were marked by bimodality in the distribution of the latitude of surface zonal-mean zonal winds. Here, ERA-Interim and NCEP/NCAR reanalysis data are used to establish if this bimodality exists in the Southern Hemisphere (SH) near-surface winds, which would predict the existence of an additional mode of tropospheric variability exhibiting stronger and longer-lived responses than what has previously been observed. Histograms of the latitudinal position of maximum near-surface zonal-mean zonal winds turn up no convincing evidence of jet bimodality, although they do reveal an interesting - but probably spurious trimodality in the NCEP/NCAR June-August 850-hPa distribution of jet latitude. A climatology of wintertime zonal winds reveals that there is a time-mean split jet over the South Pacific Ocean; furthermore, empirical orthogonal function analysis reveals that, over the South Pacific, the dominant mode of wintertime zonal wind variability is a splitting and un splitting of the jet. Ultimately, both the climatological split jet and its variability are determined not to be evidence of jet bimodality. The temporal trends in the distribution of near-surface jet latitude are also examined. Stratospheric ozone depletion has been implicated in surface circulation changes in the SH high latitudes; one of these changes has been a poleward shift of the jet in austral summer. In this thesis, it is found that a poleward shift of the December-February distribution of jet latitude has taken place from the pre-ozone-hole to ozone-hole eras, consistent with previous findings. The novel result is that there has also been a poleward shift of this distribution in May, which is consistent with a secondary maximum in ozone depletion near the tropopause in April-May as observed by other authors (Thompson et al. 2011), and would imply the occurrence of troposphere-stratosphere coupling in late fall. An in-depth investigation of these May zonal wind trends will be pursued in future work. / by Casey C. Hilgenbrink. / S.B.