Glaciology Commons^™

Horizontal Infiltration Of Water Through Porous Snow As A Gravity Current, Anthony Cheng

Dartmouth College Master’s Theses

On the surface of the Greenland ice sheet or around the margins of the Antarctic ice shelf, water infiltrates porous ice. It is important to understand this infiltration process since water populating the pore space of ice directly impacts the density, porosity, and wetness of ice. These properties influence the mechanics and tensile strength of ice, as greater amounts of infiltration result in faster or more widespread deformation events, which may lead to adverse climatic effects such as sea level rise and ocean current disruption. While studies have considered the thermodynamics and fluid mechanics of water vertically percolating through snow …

On Spatiotemporal Trends In Meter-Scale Gris Surface Roughness And The Development Of An On-Ice Laser Distance Meter, Jamie C. Good

Dartmouth College Master’s Theses

Surface roughness is a critical component of the energy and mass balance of the Greenland Ice Sheet (GrIS). However, roughness is often oversimplified in predictive models due to its inherent scale dependency. Accurate quantification of roughness, including its recent changes and driving factors, is critically important for understanding and predicting GrIS surface dynamics. Using multi- and single-scale methods of roughness analysis, I assess spatiotemporal trends in GrIS meter-scale surface roughness from 2009 to 2019 with Operation IceBridge’s Airborne Topographic Mapper ILATM2 product. Additionally, with data from on-ice automated weather stations, I employ machine learning techniques to identify primary climatic controls …

Challenges Of Using More Precise Temporal And Spatial Resolution Of Remote Sensing Data For Surface Water Quality Monitoring, Ivan Rykin

Dartmouth College Master’s Theses

Monitoring river suspended sediment concentration (SSC) is critical for environmental challenges such as understanding the fate of thawed permafrost sediment and its impact on global carbon cycling. However, traditional SSC monitoring using Landsat imagery is limited by spatial and temporal constraints, particularly for narrow rivers in cloudy and/or snowy regions.

This study investigates the use of higher spatial (3 m) and temporal (daily) resolution satellite imagery from the PlanetScope constellation to estimate SSC in remote rivers such as those in the Arctic. I compare the performance of PlanetScope’s spectral resolution (4 and 8 bands) with Landsat 7. Merging data from …

Automated Glacier Classification In High Mountain Asia Using Machine Learning And A Random Forest Classifier, Victoria Elizabeth Halvorson

Dartmouth College Master’s Theses

High Mountain Asia (HMA) is home to the largest mass of glaciers and ice outside the north and south polar regions. HMA glaciers are projected to experience accelerated mass loss from higher greenhouse gas emissions through the end of the century. Many studies of glacier mass balance and mass loss in HMA obtain glacier area from the Randolph Glacier Inventory (RGI). However, the RGI is designed to show glacier area across the world that is accurate to the year 2000 and, as a result, is not an accurate representation of the current state of glacier area in HMA. Additionally, glacier …

Parameterization Of Cryosat-2 Radar Waveforms Across The Greenland Ice Sheet, Alexander Clark Ronan

Dartmouth College Master’s Theses

Geodetic surface mass balance calculations regularly rely on satellite radar altimeters such as CryoSat-2 to understand elevation and volume changes of the Greenland Ice Sheet (GrIS). However, the impact of changing GrIS shallow subsurface stratigraphic conditions on CryoSat-2 elevation products is poorly understood. We seek to investigate the long-term impacts of changing surface and shallow subsurface conditions on CryoSat-2 Level 2 elevation products derived from the Offset Center of Gravity (OCOG), Ocean - Customer Furnished Item (CFI), and University College London (UCL) Land-Ice retracking algorithms through the analysis of radar waveform characteristics. We further investigate time series from 2010 to …

Geomorphic And Paleoclimatic Implications Of Glacial Extent Records In The Sierra Nevada Del Cocuy, Colombia During Termination 1, Jordan Nickerson Herbert

Dartmouth College Master’s Theses

Reconstructions of past glacial extents using geomorphic mapping and cosmogenic dating provide an opportunity to infer past climates. A record of the past extents of tropical mountain glaciers is particularly useful because there are few other means to reconstruct past temperatures in high-altitude, low-latitude locations. The tropics play an outsized role in mediating global climate, yet there is a lack of understanding of how the tropics may have influenced past climate changes such as the most recent deglaciation (Termination 1, ~18–11.7 ka). Improving reconstructions of tropical mountain glaciers will aid in understanding the role of the tropics in the global …