Master of Science, The Ohio State University, 2011, Geological Sciences

Tropical glaciers can provide climatic information through changes in ice area through time and from ice core records contained within them. The glaciers near Puncak Jaya in Papua, Indonesia are the last remaining glaciers in the tropical West Pacific. Several satellite based studies have been conducted to assess the glacier recession through the area, but few intensive field and no ice cores studies have been conducted on these glaciers. A field expedition to Papua highland was conducted in May - June 2010 to drill ice cores from these glaciers and to collect rain samples from different elevation in the vicinity. Three ice cores were drilled, two to bedrock measuring 32.13 m (D1) and 31.25 m (D1B) in length and the third measuring 26.19 m (D2) in length. The stable isotope records were reproducible between the longer cores with significant δ18O variability of 5 to 6‰. High aerosol events were identified between 20 and 29 meters depth and in the top eight meters. This suggests that there is no melting throughout the glacier. The dating of D1 core has not been completed yet. Low tritium concentration in D1 core and high tritium concentration recorded in precipitation at the northern sites of Papua suggests that the glaciers may have melted below the 1950s/1960s bomb horizons. Eighty three rain samples were collected from different altitudes in the southern part of Papua. The analysis results suggest that the altitude effect dominates in the Papua region. The isotopic lapse rate is about 0.23‰/100 m and 1.80‰/100 m for δ18O and δD, respectively, greater than the continentality effect of 0.09‰/km. The isotopic compositions of the rain samples generally fall on the global meteoric water line. The meteorological data analysis from automated weather stations arrayed extending from the southern coastal region up to near the glaciers shows that the surface lapse rate is about 5°C/km. Greater diurnal temperature differences are identified at below 2,500 m a.s.l and at abo (open full item for complete abstract)

Committee: Lonnie Thompson PhD (Advisor); William Lyons PhD (Committee Member); Matthew Saltzman PhD (Committee Member) Subjects: Climate Change; Geochemistry; Geography; Geological; Geology

Doctor of Philosophy, The Ohio State University, 2022, Geography

This dissertation comprises of a multi-part investigation into the impacts and contributions of debris-covered glaciers to the surface hydrology of the Cordillera Blanca, Peru. Due to the circumstances surrounding the global pandemic, the originally planned in situ dataset was not collected; however, following a pivot in research goals and objectives, field collected (prior to 2020) streamflow and water quality data, and remotely sensed imagery were used to answer the slightly broadened questions of this dissertation. First, without a specific focus on debris-covered glacier catchments, long-term hydrological shifts were identified throughout the past 70-years, and short-term daily fluctuations were assessed throughout the Rio Santa watershed. Multiple change points were identified to have occurred over the historical record, with the most recent changes in the 2000s that indicate lower rates of loss in discharge now compared to prior decades. High-temporal resolution discharge data is presented which provides evidence that diurnal changes in streamflow are driven by seasonal fluctuations and have not undergone significant shifts in timing or amplitude during the past 14-years. Second, high-resolution satellite imagery was used to calculate the spatial and temporal changes and estimate volumes of supraglacial ponds on the surface of debris-covered glaciers for the first time across the Peruvian Andes. Expanding the study area beyond the Cordillera Blanca allowed for the opportunity to test patterns in debris-covered glacier ponds more broadly and place the Cordillera Blanca in a regional context. From these analyses, debris-covered glacier pond area maxima were recorded to have occurred in 2012 and 2013 across the Peruvian Andes. Furthermore, as minimum temperatures significantly rose over the past 11 years, a decrease in total supraglacial pond area was measured. Finally, water volume estimates provide strong indications that debris-covered glaciers contribute sign (open full item for complete abstract)

Committee: Bryan Mark (Advisor); Michael Durand (Committee Member); Robert Hellstrӧm (Committee Member); Alvaro Montenegro (Committee Member) Subjects: Environmental Science; Hydrology; Physical Geography; Water Resource Management

Master of Arts, The Ohio State University, 2022, Geography

Improving tropical glacier modeling capacity is crucial for deriving climatological insight from tropical glacier fluctuations on historical to multi-millennial timescales and for predicting socially relevant glacier environmental changes under anthropogenic climate warming. Using the glacierized Queshque Valley of Peru's Cordillera Blanca as a case study, this thesis first develops data assimilation and calibration methods to adapt a coupled temperature-index mass balance and glacier flow model to tropical settings. The calibrated model is applied to project glacier evolution in the valley under an ensemble of climate change scenarios, confirming the high probability of near complete deglaciation by the end of this century. Despite the glacier's current trajectory, moraine features signal that ice once extended about 6km further down valley. Three cosmogenic nuclide dated moraines reveal extended ice cover at 10.8ka, 9.4ka, and 6.2ka BP, and historical maps show that the glaciers have retreated considerably since 1962 CE. Equilibrium experiments are used to identify all possible climatic conditions producing stable glaciers at the positions marked by the moraines and historical ice limit. Relative to the 1985-2015 CE climatic baseline, results suggest that valley temperatures were 2.9-1.9˚C cooler at 10.8ka BP and at least 1.0˚C cooler at 9.4ka BP. Proximity between the 9.6ka and 6.2ka moraines makes their climatic signatures difficult to distinguish. Finally, the equilibrium experiment confirms that in 1962 the glacier was already far out of balance. In summary, this thesis presents a data-intensive approach to improving model performance on a tropical glacier, enabling accurate ice loss projections, and helping to constrain paleoclimatic interpretations of tropical glacier geomorphology.

Committee: Bryan Mark (Advisor); Zhengyu Liu (Committee Member); Ellen Mosley-Thompson (Committee Member) Subjects: Geography; Geomorphology

Doctor of Philosophy (PhD), Ohio University, 0, Instructional Technology (Education)

At a time when the world is facing a range of significant challenges, including a rise in air temperature, rapidly evolving droughts in some areas, and floods, new technology in education can help inform people of current issues that may not be close to them but, nevertheless, can have a significant impact in the future. Our planet has been warming steadily for over a century, and the preponderance of evidence has pointed at human action as the main contributor to the change (Hansen et al., 2010). The evolution of technology has brought tremendous change. Virtual Reality (VR), 360-degree video, has the potential to bring the environment to the students since it can provide a close to a real-life situation. The use of VR for educational purposes has been quite unknown to most school systems. There are many gaps that need to be investigated prior to the effective implementation of VR-learning, such as the factors that influence students' intention to use it. This study fulfilled some of these gaps by focusing on the potential of using VR for future education and raising awareness of the climate change occurring in remote areas, specifically tropical regions. The findings of this study will hopefully encourage students to play a more responsible role in the development and implementation of VR education worldwide and help enhance the academic quality of courses for instructors and students. This study examined students' behavioral intentions towards using VR in their learning about climate change utilizing the Technology Acceptance Model of Davis (1989), combined with the spatial presence experience scale (Hartmann et al., 2015). Phase 1 was created in order to understand students' salient beliefs about the use of VR for educational purposes and learning about climate change. Furthermore, 65 students participated in this phase and reported that VR can be beneficial for educational purposes to learn about global climate change, and 95.2% of participants fully agreed. Ph (open full item for complete abstract)

Committee: Greg Kessler (Advisor); Gordon Brooks (Advisor) Subjects: Climate Change; Educational Technology; Environmental Education

Master of Science, The Ohio State University, 2009, Geological Sciences

Oxygen isotopes are useful proxy records in ice cores because of the selective fractionation process that occurs during evaporation and condensation of water molecules, yet the controls on these fractionation processes are under debate for tropical ice core records. Two ice cores from the eastern and western range of the Peruvian Andes (Quelccaya Summit Dome and Coropuna Caldera Core) are annually resolved for the last 200 years and provide an excellent means for comparison to localized instrumental meteorological records as well as regional measures of past climate. The oxygen isotope histories from these cores show no significant correlation with temperature or precipitation from two nearby meteorological stations or an automated weather station on the summit of Quelccaya. Yet significant correlation is found on a regional scale with Lake Titicaca water levels as well as equatorial Pacific sea surface temperatures over recent time. However, overall trends for the last century offer conflicting evidence to this end. On centennial and millennial time scales, temperature has been shown to be positively correlated with oxygen isotopes in tropical ice cores, yet the mechanisms for this control need further research.

Committee: Lonnie Thompson (Advisor); W. Berry Lyons (Committee Member); Bryan Mark (Committee Member) Subjects: Geology

Master of Science, The Ohio State University, 2008, Geological Sciences

Three ice cores drilled to bedrock atop Nevado Coropuna, southwestern Peru reflect Holocene and late glacial stage climate variability. Two cores measure <34 m in length yet provide seemingly continuous >16 kyr histories, and thus represent the shortest known ice cores to extend from the present into the last glacial. High major ion concentrations and dust particle diameter ratios identify a succession of abrupt and severe Holocene droughts on the Altiplano centered at 3.4, 4.2, 5.6, 7.5, 8.2 and 10.1 kyr B.P. Modern precipitation availability in the region is dominated by ENSO variability on interannual timescales and these events may thus reflect extended periods of El Nino-like conditions in the tropical Pacific. The Deglaciation Climate Reversal, the tropical counterpart to the Northern Hemisphere Younger Dryas stadial, is marked by large, abrupt stable isotopic depletion, with δ18O ~9-10 per mil lower at this time relative to the early Holocene. This δ18O shift is remarkable as it is ~4-5 per mil greater than that observed in any previously drilled central Andean ice core record. In concert with marked, synchronous deuterium-excess increases, these shifts may be explained by a coeval southward migration of the ITCZ. Decreased major ion and dust concentrations and low dust particle diameter ratios likely reflect increased central Andean precipitation at this time, in agreement with other regional paleoclimate records.A complete history could not be produced for the third core due to conflicting dating results. Annual resolution over the past 244 years allows for a detailed assessment of recent regional climate change and its relation to possible forcings. Decadal δ18O variability is strongly correlated with tropical Pacific sea surface temperatures and lends support to precipitation, via the amount effect, controlling δ18O on these timescales. On longer timescales, temperature plays an increasingly important role in governing this parameter and it is suggested t (open full item for complete abstract)

Committee: Dr. Lonnie Thompson (Advisor); Dr. W. Berry Lyons (Committee Member); Dr. Bryan Mark (Committee Member) Subjects: Geology