Glacier-climate interactions: a synoptic approach

The reliance on freshwater released by mountain glaciers and ice caps demands that the effects of climate change on these thermally-sensitive systems are evaluated thoroughly. Coupling climate variability to processes of mass and energy exchange at the glacier scale is challenged, however, by a lack of climate data at an appropriately fine spatial resolution. The thesis addresses this challenge through attempting to reconcile this scale mismatch: glacier boundary-layer observations of meteorology and ablation at Vestari Hagafellsjökull, Iceland, and Storglaciären, Sweden, are related to synoptic-scale meteorological variability recorded in gridded, reanalysis data. Specific attention is directed toward synoptic controls on: i) near-surface air temperature lapse rates; ii) stationarity of temperature-index melt model parameters; and iii) glacier-surface ablation. A synoptic weather-typing procedure, which groups days of similar reanalysis meteorology into weather categories , forms the basis of the analytical approach adopted to achieve these aims. Lapse rates at Vestari Hagafellsjökull were found to be shallowest during weather categories characterised by warm, cloud-free weather that encouraged katabatic drainage; steep lapse rates were encountered in weather categories associated with strong synoptic winds. Quantitatively, 26% to 38% of the daily lapse-rate variability could be explained by weather-category and regression-based models utilizing the reanalysis data: a level of skill sufficient to effect appreciable improvements in the accuracy of air temperatures extrapolated vertically over Vestari Hagafellsjökull. Weather categories also highlighted the dynamic nature of the temperature-ablation relationship. Notably, the sensitivity of ablation to changes in air temperature was observed to be non-stationary between weather categories, highlighting vulnerabilities of temperature-index models. An innovative solution to this limitation is suggested: the relationship between temperature and ablation can be varied as a function of weather-category membership. This flexibility leads to an overall improvement in the simulation of daily ablation compared to traditional temperature-index formulations (up to a 14% improvement in the amount of variance explained), without the need for additional meteorological data recorded in-situ. It is concluded that weather categories are highly appropriate for evaluating synoptic controls on glacier meteorology and surface energetics; significant improvements in the parameterization of boundary-layer meteorology and ablation rates are realised through their application

An Assessment of the Relationship between Glacier Mass Balance and Synoptic Climate in Norway: Likely future implications of climate change.

Regional variations in temperature and precipitation from selected European stations are found to be significantly related to large-scale modes of atmospheric variability in the North Atlantic. Increased westerlies over Europe, particularly since the 1970s, are shown to significantly contribute to increases in temperature and precipitation over northern Europe while suppressing the penetration of warm, moist air into more southern European locations. These regional variations, primarily resulting from changes in the atmospheric circulation, are found to largely explain the divergent response evident in glacier mass balance, between Scandinavia and the Alps, over the last 30 years.To further examine these linkages, a Temporal Synoptic Index(TSI) was derived for a number of locations in Norway. Principal Components Analysis (PCA) and subsequent clustering of component scores is used to classify days for both winter and summer seasons over the period 1968-1997. Findings indicate that the occurance of 'warm' type air masses during the summer months have increased in frequency, particularly since the late 1980s. However, temperatures were also found to be decreasing in these clusters. A general decrease in the frequency of 'cold' cluster types during the winter months is evident until the early 1990s. These decreases were largely compensated for by increases in the frequency of 'warm' types, with an increased moisture carrying capacity,particularly since the late 1970s. The frequency occurence of these key air mass types was shown to be significantly related to glacier mass balance during both the accumulation and ablation season. Winter air mass types from maritime source regions act to enhance accumulation and suppress ablation, while summer continental source types suppress accumulation and enhance ablation. Statistically downscale output from the HadCM3 GCM for two locations in southern Norway indicate mean winter temperatures are likely to increase by -1.25°C by the end of the present century with the largest increases occurring during December and January. Summer increase are suggested to be in the region of -2.5°C, with a more marked increase of up to -3.5°C during the month of August. Based on these scenarios, a Temporal Synoptic Index for the period 1997-2099 is constructed. This index is then used to predict glacier mass balance, used as input into an ice-flow model for Rembesdalskaka, in southern Norway, to access likely future changes in glacier behaviour as a consequence of anthropogenic climate change. Results for the ice-flow model indicate that the equilibrium line altitude (ELA) of Rembesdalskaka is likely to increase in altitude from its average 1968-1997 position of 1650 metres to 1750 metres by end of century resulting in a retreat of front position of nearly 3km. Despite a decreasing glacier net balance which commences around 2010,increases in summer ablation only become a siqnificant contributor to net balance after 2040, resulting in an advance of the glacier front of up to 1km during the first few decades of the century. These findings suggest that the hydroelectric power industry in Norway is likely to be beneficiary of the projected changes in glacier behaviour arising from climate change

Glacier Monitoring in Ladakh and Zanskar, northwestern India

Glaciers in the Himalaya are often heavily covered with supraglacial debris, making them difficult to study with remotely-sensed imagery alone. Various methods such as band ratios can be used effectively to map clean-ice glaciers; however, a thicker layer of debris often makes it impossible to distinguish between supraglacial debris and the surrounding terrain. Previously, a morphometric approach employing an ASTER-derived digital elevation model (DEM) has been used to map glaciers in the Khumbu Himal and the Tien Shan. This project aims first to test the ability of the morphometric procedure to map small glaciers; second, to use the morphometric approach to map glaciers in Ladakh; and third, to use Landsat and ASTER data and GPS and field measurements to monitor glacier change in Ladakh over the past four decades. Field work was carried out in the summers of 2007 and 2008. For clean ice, a ratio of shortwave infrared (SWIR, 1.6-1.7 µm) and near infrared (NIR, 0.76-0.86 µm) bands from the ASTER dataset was used to distinguish snow and ice. For debris-covered glaciers, morphometric features such as slope, derived from a DEM, were combined with thermal imagery and supervised classifiers to map glacial margins. The method is promising for large glaciers, although problems occurred in the distal and lateral parts and in the forefield of the glaciers. The morphometric approach was inadequate for mapping small glaciers, due to a paucity of unique topographic features on the glaciers which can be used to distinguish them from the surrounding terrain. A multi-temporal analysis of three glaciers in Ladakh found that two of them have receded—one since at least the mid-1970s, the other since at least 2000—while a third glacier, Parkachik Glacier, seemed to have retreated in the 1980s, only to advance in the 1990s and early 2000s. However, from 2004-2008 it showed only negligible change making its current status difficult to determine without further monitoring. The glacier outlines derived during this project will be added to the Global Land Ice Measurements from Space (GLIMS) database. In testing the limits of the morphometric approach, the thesis has provided a valuable contribution to the present literature and knowledge-base regarding the mapping of debris-covered glaciers

Climate change impact on the hydrological functioning of mountain lakes: a conceptual framework

Mountain lakes are distinctive water bodies that attract the great attention of researchers. They not only serve as a crucial water resource for the inhabitants of the upland regions but also as an important destination for millions of tourists who are attracted by the beauty of these water bodies. With the increasing concern about global warming, mountain lakes are experiencing changes in their hydrological processes and meanwhile can act as reflectors of those changes. Specifically, due to the fragility of these water bodies, understanding the consequences is significant as it can help to find out whether climate change causes degradations in lake hydrological functioning. The interactions of hydrological processes in mountain lakes with external drivers are usually hard to explain explicitly owing to their complexity. To deal with that problem, scholars tend to use conceptual frameworks, which help to reveal the dependence of a lake on particular hydrologic factors. To identify factors influencing lake hydrological function and their sensitivity to changing climate, a literature analysis was undertaken. The focus was on the Canadian Rocky Mountains where 5155 water bodies were identified using GIS. The main literature sources used to identify factors influencing lake hydrologic function were peer-reviewed articles and books. In total, 10 natural drivers critical for lake hydrological function and 2 main reflectors of climate change impacts on mountain lakes as well as 38 additional sub-factors that characterize each of the factors and reflectors, were identified. Based on that, a conceptual framework for mountain lake hydrological functioning was developed. The major problem that affected the thorough testing of the conceptual framework was a limited number of observations across lakes in the research area. Nevertheless, the conceptual framework is flexible and might be tested across many mountainous regions worldwide that experience climatic changes. Such an opportunity can be realized through the use of quantitative statistical techniques available for large datasets. Overall, the conducted research stresses the problem of a poor degree of hydrological exploration of lakes in mountain regions and presents a useful approach to represent complex interactions of natural drivers and intra-lake processes under rising temperatures

Gazing at the Solar System: Capturing the Evolution of Dunes, Faults, Volcanoes, and Ice from Space

Gazing imaging holds promise for improved understanding of surface characteristics and processes of Earth and solar system bodies. Evolution of earthquake fault zones, migration of sand dunes, and retreat of ice masses can be understood by observing changing features over time. To gaze or stare means to look steadily, intently, and with fixed attention, offering the ability to probe the characteristics of a target deeply, allowing retrieval of 3D structure and changes on fine and coarse scales. Observing surface reflectance and 3D structure from multiple perspectives allows for a more complete view of a surface than conventional remote imaging. A gaze from low Earth orbit (LEO) could last several minutes allowing for video capture of dynamic processes. Repeat passes enable monitoring time scales of days to years. Numerous vantage points are available during a gaze (Figure 1). Features in the scene are projected into each image frame enabling the recovery of dense 3D structure. The recovery is robust to errors in the spacecraft position and attitude knowledge, because features are from different perspectives. The combination of a varying look angle and the solar illumination allows recovering texture and reflectance properties and permits the separation of atmospheric effects. Applications are numerous and diverse, including, for example, glacier and ice sheet flux, sand dune migration, geohazards from earthquakes, volcanoes, landslides, rivers and floods, animal migrations, ecosystem changes, geysers on Enceladus, or ice structure on Europa. The Keck Institute for Space Studies (KISS) hosted a workshop in June of 2014 to explore opportunities and challenges of gazing imaging. The goals of the workshop were to develop and discuss the broad scientific questions that can be addressed using spaceborne gazing, specific types of targets and applications, the resolution and spectral bands needed to achieve the science objectives, and possible instrument configurations for future missions. The workshop participants found that gazing imaging offers the ability to measure morphology, composition, and reflectance simultaneously and to measure their variability over time. Gazing imaging can be applied to better understand the consequences of climate change and natural hazards processes, through the study of continuous and episodic processes in both domains

Earth System Modeling 2.0: A Blueprint for Models That Learn From Observations and Targeted High-Resolution Simulations

Climate projections continue to be marred by large uncertainties, which originate in processes that need to be parameterized, such as clouds, convection, and ecosystems. But rapid progress is now within reach. New computational tools and methods from data assimilation and machine learning make it possible to integrate global observations and local high-resolution simulations in an Earth system model (ESM) that systematically learns from both. Here we propose a blueprint for such an ESM. We outline how parameterization schemes can learn from global observations and targeted high-resolution simulations, for example, of clouds and convection, through matching low-order statistics between ESMs, observations, and high-resolution simulations. We illustrate learning algorithms for ESMs with a simple dynamical system that shares characteristics of the climate system; and we discuss the opportunities the proposed framework presents and the challenges that remain to realize it.Comment: 32 pages, 3 figure

Statistical models for animal telemetry data with applications to harbor seals in the Gulf of Alaska

2017 Spring.Includes bibliographical references.Much is known about the general biology and natural history of harbor seals (Phoca vitulina), but questions remain about the aquatic and terrestrial space use of these marine mammals. This is in large part because methods for examining the spatial ecology of harbor seals are poorly developed. The objective of this dissertation is to pair existing telemetry data with contemporary spatio-temporal modeling to quantify the space use and resource selection of harbor seals in the coastal waters of southern Alaska. Recent extensions to models for analyzing animal telemetry data address complications such as autocorrelation and telemetry measurement error; however, additional challenges remain, especially in the context of analyzing Argos satellite telemetry data collected on marine mammals like harbor seals. For example, existing methods assume elliptical (or circular) patterns of measurement error, even though Argos satellite telemetry devices impose more complicated error structures on the data. Constraints, or barriers, to animal movement present another complication. Harbor seals and other marine mammals are constrained to move within the marine environment, and mechanistic models that do not adhere to movement barriers yield unreliable inference. Therefore, a primary goal of this research is to develop statistical tools that account for these nuances and provide rigorous, ecologically relevant inference. Even though the models presented in this dissertation were specifically developed with Argos satellite telemetry data and harbor seals in mind, the methods are general and can be applied to other species and types of telemetry data. This dissertation consists of five chapters. In Chapter 1, I briefly discuss the general biology of harbor seals, focusing on what is known about their spatial habits in Alaska. I then summarize trends in Alaskan harbor seal abundance, a topic that motivated my research as well as the work of many others. I describe the existing Alaska Department of Fish and Game telemetry data sets that are available for examining harbor seal spatial ecology, commonly-used statistical methods for analyzing animal telemetry data, and conclude with the objectives of my research and an outline for the remainder of the dissertation. In Chapter 2, I propose an approach for obtaining resource selection inference from animal location data that accounts for complicated error structures, movement constraints, and temporally autocorrelated observations. The model consists of two general components: a model for the true, but unobserved, animal locations that reflects prior knowledge about constraints to animal movement, and a model for the observed telemetry locations that is conditional on the true locations. I apply the model to simulated data, showing that it outperforms common ad hoc approaches used when confronted with telemetry measurement error and movement constraints. I then apply the framework to obtain inference concerning aquatic resource selection and space use for harbor seals near Kodiak Island, Alaska. Chapters 3 and 4 shift the focus from inference concerning aquatic space use and resource selection, to inference concerning the use of coastal resources (i.e., haul-out sites) by harbor seals. In Chapter 3, I present a fully model-based approach for estimating the location of central places (e.g., haul-out sites, dens, nests, etc.) from telemetry data that accounts for multiple sources of uncertainty and uses all of the available locational data. The model consists of an observation model to account for large telemetry measurement error and animal movement, and a highly flexible mixture model (a Dirichlet process) to identify the location of central places. Ancillary behavioral data (e.g., harbor seal dive data obtained from the satellite-linked depth recorders) are also incorporated into the modeling framework to obtain inference concerning temporal patterns in central place use. Based on the methods developed in Chapter 3, I present a comprehensive analysis of the spatio-temporal patterns of haul-out use for harbor seals near Kodiak Island in Chapter 4. Chapter 4 also extends previously developed methods to examine the affect of covariates on haul-out site selection and to obtain population-level inference concerning haul-out use. I conclude, in Chapter 5, with some general thoughts about analyzing animal telemetry data, as well as potential future research directions

Simulating past and future mass balance of Place Glacier using a physically-based, distributed glacier mass balance model

The objective of this study is to develop a physically-based distributed glacier mass balance (GMB) model for Place Glacier, British Columbia, Canada, and apply the model to develop the historic and the future mass balance. The model is forced with climate data from Regional Atmospheric Modeling System (RAMS) mesoscale atmospheric model output from 1979-2008 for developing historic mass balance on Place Glacier. The model is also run in the future (2009-2040) to develop a projection of mass balance. The model simulated the historic glacier-wide summer and winter balance on Place Glacier satisfactorily. For all years, root mean squared error (RMSE) in simulated summer and winter balance are 0.43 m water equivalent (w.e.) and 0.27 m w.e., respectively. Over the period of 29 years, the model simulated a cumulative net mass balance of -33.72 m w.e. The model outperformed both empirical temperature index (TI) and enhanced TI models in simulating summer balance on Place Glacier when forced with the same RAMS variables. A linear regression model based on Singular Value Decomposition (SVD) technique is used for downscaling future climate projections from a suite of Global Climate Models (GCMs). The cross-validation of downscaled daily air temperature showed a strong correlation with the validation dataset (r~ =0.85, p <0.05). However, the RMSE in downscaled daily air temperature is large (=2.4~C). With spatially average correlation of 0.38 and RMSE of 7.5 mm day\u207b~ , the model for daily precipitation performed less satisfactorily in downscaling large-scale precipitation. For all variables, the error statistics improved with the monthly model. Future GCM projections form CanESM2, MIROC-ESM, MPI-ESM-LR, and HadGEM2-ES, are considered for downscaling. CanESM2 predicted a large negative glacier-wide net mass balance of -2.50 m w.e. for Place Glacier in the future. For the remaining GCMs, the average of net mass balance is \u20130.96 m w.e. The average of the cumulative mass loss predicted from GCMs other than CanESM2 is -31 m w.e. From 2009-2040, CanESM2, MIROC, MPI and HadGEM2 predicted an area loss of 52%, 28% and 22%, respectively. Overall, all downscaled GCMs, except CanESM2, performed better in predicting future mass balance for Place Glacier.The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b205525

Hydrochemical Signatures of Glacial Meltwater on Volcán Chimborazo, Ecuador

University of Minnesota M.S. thesis. November 2017. Major: Earth Sciences. Advisors: G.H. Crystal Ng, Andrew Wickert. 1 computer file (PDF); viii, 110 pages.Glacier recession in the tropical Andes is generating significant concern over future water availability for domestic use, irrigation, and hydropower. Sparse data sets, extreme heterogeneity in climate patterns, and the limited understanding of groundwater and ecohydrological processes in these catchments make predicting the hydrologic response to glacier retreat difficult. Here I examine a glaciated watershed on Volcán Chimborazo, Ecuador. I use geospatial analysis and recent geologic studies to evaluate the vegetation and geologic factors that influence the hydrologic response of the watershed. Additionally, I utilize hydrochemical and stable isotope signatures to investigate how melt and groundwater contributions to streamflow have changed over time along with possible meltwater-groundwater connections. A new landcover map of Volcán Chimborazo, generated using object based image analysis, reveals a significant increase in the upper limit of vegetation on the mountain and expansion of crop and pasture land since 1978. Geologic cross-sections, based on recent studies, show that near surface geology is dominated by glacial deposits and underlain by relatively young volcanic bedrock. Results from a hydrochemical mixing model (HBCM) combined with discharge measurements reveal spatial variability in groundwater discharge and suggest that groundwater discharge during the dry season has decreased from 2012-2017. Short time scale variability is clearly influenced by precipitation, but long-term discharge trends remain uncertain. Lastly, stable isotope and solute concentrations in samples suggest groundwater in the study watershed is recharged by precipitation falling at high elevations where ice and snow may dominate the hydrologic system