Doctor of Philosophy, The Ohio State University, 2014, Geography

Climate change will impact hydrological systems worldwide, and human societies will face increasing water resource vulnerabilities as a result. One key concern is the potential downstream impact of glacier recession in the world's tropical and temperate mountains. For communities at the foot of Ecuador's ice-capped volcanoes, glacial meltwater is a potentially important component of irrigation supply, and residents observe the region's rapidly retreating glaciers with mounting concern. In this dissertation, I present results from a uniquely integrative study examining the relationships among glacier retreat, hydrological change and water resource insecurity at Volcan Chimborazo. Combining remote sensing analyses, direct hydrological measurements, climate data analyses, and detailed household surveys, I report on the recent rate of glacier shrinkage, the role of glacial meltwater in the local hydrological system, the increasing insufficiency of water entering local irrigation systems, and the livelihood adaptations made necessary by increasing water stress. Results show that while Chimborazo lost 21% ± 9% of its glacier area between 1986 and 2013, each of Chimborazo's glacierized watersheds is a groundwater-dominated system. Even in the upper Rio Mocha, the only catchment where glacier meltwater is a regular component of surface runoff, glaciers generally directly contribute only ~5% of total discharge. There are indications of strong linkages between glacier meltwater and groundwater discharge, however, and this merits further investigation. Still, water stress is a prominent factor driving widespread local perceptions of reduced socio-economic well-being in recent decades. While instrumental records document a local warming trend of 0.11°C per decade since 1986, they do not indicate a shift in local precipitation patterns. However, local farmers are nearly unanimous in their perception that precipitation has decreased, and the spatial patterns of glacier change (open full item for complete abstract)

Committee: Bryan Mark (Advisor); Michael Durand (Committee Member); W. Berry Lyons (Committee Member); Kendra McSweeney (Committee Member); Ellen Mosley-Thompson (Committee Member) Subjects: Climate Change; Geography; Hydrology; Latin American Studies; 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, The Ohio State University, 2017, Environmental Science

The cryosphere is shrinking as a result of climate change. Mountain glaciers, a key component of the cryosphere, serve as headwaters to glacier meltwater streams which support communities of stenothermic organisms. The Tibetan plateau is known as "the Third Pole" for its high number of glaciers, yet very few scientific papers have been published on aquatic invertebrate ecology of glacier-fed streams in the region. On the edges of the Tibetan Plateau in Southeast Tibet's Hengduan mountains, monsoonal temperate glaciers extend well below the treeline as valley glaciers, and are perhaps the most endangered cryosphere-dominated streams in the world due to their low latitudes and altitudes, which makes them sensitive to atmospheric temperature changes. The glaciated headwaters of the Mekong and Yangtze Rivers comprise a small fraction of the annual river discharge, yet at a local scale provide glacial meltwater that supports endemic and potentially rare species. Water temperature and channel stability differ between seasons due to the torrential flow from glacial meltwater during the summer melt season. The Milner & Petts (M&P) model of macroinvertebrate presence in glacier streams was based on the environmental factors of water temperature and channel stability during the summer melt season. In low temperature water close to the glacier, the macroinvertebrate communities are generally limited to Diamesinae chironomids, and further downstream more taxa are found where water temperature and channel stability increase. Therefore, temperature and channel stability are examined as potential limiting factors on the distribution of invertebrate communities, with the goal to compare the insect communities in Southeastern Tibet's glacier-fed streams with the widely-accepted M&P model of invertebrate community structure. Since discharge and hydrology may influence invertebrate distribution in glacier streams, hydraulic characteristics and invertebr (open full item for complete abstract)

Committee: Lanno Lanno Dr. (Advisor); David Denlinger Dr. (Committee Member); Richard Moore Dr. (Committee Member); Donald Dean Dr. (Committee Member) Subjects: Environmental Science

Master of Arts, The Ohio State University, 2015, Geography

The following thesis investigates glacier recession, climate change, and water resources, specifically glacier melt and groundwater contributions to surface water discharge in the Shullcas River watershed in 2014, near the city of Huancayo, Peru. The Shullcas River watershed is a glacierized mountainous region of the Central Andes that has experienced rapid rates of glacier recession over the past 25-30 years (Lopez-Moreno et al, 2012). My interests are particular to the intersection of human and natural systems, and using the conceptual framework developed by socio-hydrologists I argue that the Shullcas River watershed is a profoundly coupled human-water system (Carey et al., 2014; Swyngedouw, 2009). Using a mixed methods approach to research during eight weeks of fieldwork, I conducted synoptic scale hydrochemical sampling while carrying out ten semi-structured interviews with a diverse set of water users from the region. As a result of this investigation we now have a synoptic snapshot of the Shullcas River watershed as it relates to the Huaytapallana glacier melt water contribution to surface water discharge in the Shullcas River. Using the Hydrochemical Basin Characterization Method for a single dry season in 2014, the glacier melt contribution to stream flow is estimated to be between 8.9-16.6% of the Shullcas River discharge upstream from pump stations for local agricultural canals and the drinking water supply for the city of Huancayo, Peru. The interviews reveal that many participants noted changes in the hydrologic cycle in recent years. Participants observed that precipitation is more variable and there have been observed reductions in the water levels of tributaries and the Shullcas River during both the rainy and dry seasons. The interviews also show participants' experiences of climate change within the context of glacier recession, specifically through the use of narrative and memories of particular life events near or related to the Huaytapallana gla (open full item for complete abstract)

Committee: Bryan Mark (Advisor); Kendra McSweeney (Committee Member) Subjects: Geography

PhD, University of Cincinnati, 2012, Arts and Sciences: Geology

Accompanying the drastic increase of global temperatures observed since the end of the nineteenth century, and particularly during the last decades, glaciers worldwide have experienced rapid retreating trend. Considering the magnitude of the climate change projected for the next decades, and the potential impacts of glacier retreat on human livelihood, a thorough comprehension of climate-glacier interaction is critical in order to i) predict the response of glaciers to the different scenarios of climate change and ii) reconstruct the climatic conditions associated with former glacial fluctuations, which in turn could provide important background information for the study of both natural cycles and human impacts on climate change. This study explores the magnitude of response of the equilibrium line altitude (ELA) to different scenarios of climate change, along the climatically diverse Andes range, and its applicability to reconstruct paleoclimates. A statistical analysis of the climatic conditions at 234 glacier sites permits to classify the climate that host present-day Andean glaciers into seven groups. These groups have a distinctive geographical distribution. It has been suggested that glaciers located in different climates could respond with different magnitude to similar climatic perturbations. Here, a full-surface energy and mass balance (SEMB) model was applied to quantify the ELA sensitivity to climate across glaciated Andean regions. The results suggest that there is spatial variability in the magnitude of response of the ELA to uniform changes in temperature and precipitation, and that the spatial pattern of this variability has a general correspondence with the climatic groups identified along the Andes. The most sensitive areas to changes in temperature are the inner tropics, whereas precipitation sensitivities are relatively greater in the subtropics and northernmost mid-latitudes. It is suggested that the variability in the ELA sensitivity has implic (open full item for complete abstract)

Committee: Thomas Lowell PhD (Committee Chair); Michael Kaplan PhD (Committee Member); Patricio Moreno PhD (Committee Member); Warren Huff PhD (Committee Member); Lewis Owen PhD (Committee Member) Subjects: Geology

Master of Science, The Ohio State University, 2012, Geological Sciences

While iceberg calving makes up a substantial portion of mass loss for marine-terminating glaciers, these dynamics remain poorly represented in predictions of sea-level rise and large-scale climate models, requiring more robust observational datasets. Breiðamerkurjokull glacier functions as a uniquely controlled field setting for obtaining a wide variety of environmental and geodetic measurements in conjunction with monitoring calving flux, making it possible to more carefully constrain the sometimes-contradictory relationships between calving and environmental conditions observed in previous studies. A time-lapse camera and water level logger were placed roughly 1 km from the glacier ice front to monitor ice loss and iceberg-generated tsunamis from April to September 2011. This record was used to estimate the volume of ice lost by calving during this period and obtain calving rates on hourly, daily, and weekly timescales. Weather, tide, and contemporaneous records of the temperature-salinity structure of the lagoon were used to examine relationships between these factors and calving. Calving was shown to be more common during the falling tide in both spring and fall.

Committee: Ian Howat PhD (Advisor); W. Berry Lyons PhD (Committee Member); Lonnie Thompson PhD (Committee Member) Subjects: Geology

Master of Arts, The Ohio State University, 2012, Geography

Dramatic glacier loss in the upper Santa River watershed in Ancash, Peru has significant impact on proglacial hydrologic systems, with implications for downstream impact on human water use activities. Glacial resources serve as freshwater reservoirs, mitigating the rain shadow effect that deprives the western slopes of the Andes of regular annual water resources via precipitation. The reduction of glacial resources is coincidental with economic and population growth, and concern for the quality and quantity of water resources drives research that contributes to understanding regional hydrologic systems. This thesis integrates hydrochemical analysis and spatial exploration with the aim of assessing inorganic water quality characteristics and determinant processes within the region. The chemistry of proglacial surface waters is primarily determined by weathering processes in rock-water contact areas, and pristine glacial meltwater inherits the chemical properties of the surficial lithology along a flow path. Hydrochemical analysis methods identify elemental characteristics that are unique to the study region. Dominant hydrochemical processes include silicate weathering, coupled pyrite oxidation with silicate weathering, and to a lesser extent, carbonate weathering. Sulfate constituent is unusually high for portions of the study region and is attributed to highly acidified waters immediately downstream from glacial point sources. Geovisualization and exploratory data analysis extend the results of the hydrochemical analysis by showing temporal change and suggesting connections between lithology, areas of high erosion and weathering rates, rapid deglaciation, and elevated sulfate concentrations.

Committee: Bryan Mark PhD (Advisor); Darla Munroe PhD (Committee Member); Ahlqvist Ola PhD (Committee Member) Subjects: Climate Change; Geochemistry; Geographic Information Science; Geography; Geological; Geology; Inorganic Chemistry; Latin American Studies