Physical Sciences and Mathematics Commons^™

Characterization Of Boreal-Arctic Vegetation Growth Phases And Active Soil Layer Dynamics In The High-Latitudes Of North America: A Study Combining Multi-Year In Situ And Satellite-Based Observations, Michael G. Brown

Dissertations, Theses, and Capstone Projects

This dissertation examined the seasonal freeze/thaw activity in boreal-Arctic soils and vegetation physiology in Alaska, USA and Alberta, Canada, using in situ environmental measurements and passive microwave satellite observations. The boreal-Arctic high-latitudes have been experiencing ecosystem changes more rapidly in comparison to the rest of Earth due to the presently warming climatic conditions having a magnified effect over Polar Regions. Currently, the boreal-Arctic is a carbon sink; however, recent studies indicate a shift over the next century to become a carbon source. High-latitude vegetation and cold soil dynamics are influenced by climatic shifts and are largely responsible for the regions …

Understanding The Impacts Of Freshwater Fluxes On The Biogeochemistry Of The Coastal Arctic: A Case Study Of Prudhoe Bay, Francesca Lingo

Dissertations and Theses

The Arctic region, undergoing significant environmental changes due to rapid warming, faces alterations in air temperatures, melting permafrost, declining sea ice, and changes in riverine inputs. These shifts have profound implications for Arctic coastal ecology and biogeochemical cycles. This study, focusing on Alaska's North Slope, explores the influence of freshwater fluxes on water optical properties, vital for accurate satellite remote sensing interpretations. Our approach combined field measurements, existing data, and satellite remote sensing retrievals to identify biogeochemical gradients and their seasonal and interannual variations. A novel finding was the unique CDOM composition in Prudhoe Bay, characterized by a lower molecular …

Satellite Evidence Of Canopy-Height Dependence Of Forest Drought Resistance In Southwestern China, Peipei Xu, Wei Fang, Tao Zhou, Hu Li, Xiang Zhao, Spencer Berman, Ting Zhang, Chuixiang Yi

Publications and Research

The frequency and intensity of drought events are increasing with warming climate, which has resulted in worldwide forest mortality. Previous studies have reached a general consensus on the size-dependency of forest resistance to drought, but further understanding at a local scale remains ambiguous with conflicting evidence. In this study, we assessed the impact of canopy height on forest drought resistance in the broadleaf deciduous forest of southwestern China for the 2010 extreme drought event using linear regression and a random forest (RF) model. Drought condition was quantified with standardized precipitation evapotranspiration index (SPEI) and drought resistance was measured with the …

Application Of The Revised Universal Soil Loss Equation To Develop A Management Plan In The Chittagong Hill Tracts Region Of Bangladesh, Nira Rahman

Theses

Land degradation from soil erosion is a major issue in hilly areas of tropical regions such as the Chittagong Hill Tracts (CHT) of Bangladesh. The combination of an elevated topography, high-intensity storms that are further exacerbated by the impacts of climate change, and farming practices increase the susceptibility of the region to soil erosion. The Revised Universal Soil Loss Equation (RUSLE) was developed in the mid-latitude dry climate zone of the United States during the 1990s to assist soil conservationists in implementing farming strategies that would address soil loss. Since then, researchers employed remote sensing and geographic information systems (GIS) …

Tidal Wetland Inundation And Vegetation Phenology From Space: A Synthesis Of Approaches For Characterizing Ecological Status And Inundation Dynamics In Tidal Wetlands With Remote Sensing Observations, Brian T. Lamb

Dissertations, Theses, and Capstone Projects

This dissertation focuses on the monitoring and characterization of tidal marshes using remote sensing-based approaches. Chapter 1 introduces the topics of wetland ecology and remote sensing. Chapters 2-4 are the main research chapters of the dissertation covering the topics of tidal marsh mapping, tidal marsh vegetation characterization, and assessment of tidal marsh inundation patterns. Chapter 5 summarizes the preceding chapters and highlights future research directions.

The primary research objective of Chapter 2 is the mapping and study of tidal marshes of the Chesapeake and Delaware Bays. This chapter also features a thematic focus on the evaluation of various forms of …

Analysis Of Surface Temperature Trends Of Global Lakes Using Satellite Remote Sensing And In Situ Observations, Christal Jean Soverall, Zahida Yasmin, Mahoutin Godnou, Wen Yong Huang, Ryan Chen, Abdou Bah, Hamidreza Norouzi, Reginald Blake

Publications and Research

Even though lakes make up a small percentage of the water bodies on the global land surface, lakes provide critically important ecosystem services. Unfortunately, however, several lake surface areas around the globe have been changing with many of them drastically decreasing due to climate variability and local mismanagement at the basin-scale level. Lake Surface Water Temperature (LSWT) is recognized as a critical indicator of climate change in lakes. The changes in water and the surrounding land temperatures may be an indicator of climate variability if there is consistency between changes in both temperatures. This project focuses on the application of …

Development Of Geospatial And Temporal Characteristics For Hispaniola’S Lake Azuei And Enriquillo Using Landsat Imagery, Mahrokh Moknatian, Michael Piasecki, Jorge Gonzalez

Publications and Research

In this paper, we used Landsat imagery for water body identification to create a novel 36-year surface area extent time series for lakes Azuei (Haiti) and Enriquillo (Dominican Republic) aimed at illuminating the dramatic temporal changes of these two lakes not just at yearly but at monthly or even sub-monthly scales. We used the Normalized Difference Water Index (NDWI) to extract water features and we also used spatial differentiation and thresholding techniques to remove clouds and associated shadows from the scene that were then passed through gap filling algorithms to complete and extract the lake extent polygons. We also explored …

Guidance Index For Shallow Landslide Hazard Analysis, Cheila Cullen

Dissertations, Theses, and Capstone Projects

Rainfall-induced landslides are one of the most frequent hazards on slanted terrains. They lead to considerable economic losses and fatalities worldwide. Intense storms with high-intensity and long-duration rainfall have high potential to trigger rapidly moving soil masses due to changes in pore water pressure and seepage forces. Nevertheless, regardless of the intensity-duration of the rainfall, shallow landslides are influenced by antecedent soil moisture conditions. To the present day, no system exists that dynamically interrelates these two factors.

This work establishes a relationship between antecedent soil moisture and rainfall expressed in the form of a Shallow Landslide Index (SLI) at 1km …

Estimating The Probability Of Vegetation To Be Groundwater Dependent Based On The Evaluation Of Tree Models, Isabel C. Pérez Hoyos, Nir Y. Krakauer, Reza Khanbilvardi

Publications and Research

Groundwater Dependent Ecosystems (GDEs) are increasingly threatened by humans’ rising demand for water resources. Consequently, it is imperative to identify the location of GDEs to protect them. This paper develops a methodology to identify the probability of an ecosystem to be groundwater dependent. Probabilities are obtained by modeling the relationship between the known locations of GDEs and factors influencing groundwater dependence, namely water table depth and climatic aridity index. Probabilities are derived for the state of Nevada, USA, using modeled water table depth and aridity index values obtained from the Global Aridity database. The model selected results from the performance …

A Review Of Advances In The Identification And Characterization Of Groundwater Dependent Ecosystems Using Geospatial Technologies, Isabel C. Pérez Hoyos, Nir Y. Krakauer, Reza Khanbilvardi, Roy A. Armstrong

Publications and Research

Groundwater Dependent Ecosystem (GDE) protection is increasingly being recognized as essential for the sustainable management and allocation of water resources. GDE services are crucial for human well-being and for a variety of flora and fauna. However, the conservation of GDEs is only possible if knowledge about their location and extent is available. Several studies have focused on the identification of GDEs at specific locations using ground-based measurements. However, recent progress in remote sensing technologies and their integration with Geographic Information Systems (GIS) has provided alternative ways to map GDEs at a much larger spatial extent. This paper presents a review …

Utilizing Remote Sensing Imagery To Monitor Vegetation Change Within World Heritage Sites, Mimi Eve Hatzis

Theses and Dissertations

ABSTRACT

World Heritage sites provide a glimpse into the stories and civilizations of the past. There are currently 1007 unique World Heritage properties with 779 being classified as cultural sites, 197 as natural sites, and 31 falling into the categories of both cultural and natural sites (UNESCO & World Heritage Centre, 1992-2015). However, of these 1007 World Heritage sites, at least 46 are categorized as in danger and this number continues to grow. These unique and irreplaceable sites are exceptional because of their universality. Consequently, since World Heritage sites belong to all the people of the world and provide inspiration …

Intra- And Inter-Seasonal Variability Of Supra-Glacial 1 Streams And Lakes Over The West Greenland Ice Sheet 2 From High-Resolution Satellite Optical Data, Michael Gregory Brown

Dissertations and Theses

The Greenland ice sheet (GrIS) is one of the largest glacial ice masses on Earth, second only to the Antarctic ice sheet. The surface hydrology of the GrIS plays a crucial role on the surface energy and mass balance budgets of the ice sheet as a whole. Surface water, known as supra-glacial water, is seasonally found in the ablation zone and feeds the en-glacial and sub-glacial hydrological environments of the ice sheet. The spatial distribution of surface streams is poorly understood and their temporal variability is (to our knowledge) unknown. One of the reasons for the lack of knowledge on …

Assessing The Performance Of A Northern Gulf Of Mexico Tidal Model Using Satellite Imagery, Stephen C. Medeiros, Scott C. Hagen, Naira Chaouch, Jesse Feyen, Marouane Temimi, John F. Weishampel, Yuji Funakoshi, Reza Khanbilvardi

Publications and Research

Tidal harmonic analysis simulations along with simulations spanning four specific historical time periods in 2003 and 2004 were conducted to test the performance of a northern Gulf of Mexico tidal model. A recently developed method for detecting inundated areas based on integrated remotely sensed data (i.e., Radarsat-1, aerial imagery, LiDAR, Landsat 7 ETM+) was applied to assess the performance of the tidal model. The analysis demonstrates the applicability of the method and its agreement with traditional performance assessment techniques such as harmonic resynthesis and water level time series analysis. Based on the flooded/non-flooded coastal areas estimated by the integrated remotely …

A Handheld Polarimeter For Aerosol Remote Sensing, James W. Frost, Fouad Nasraddine, J. Rodriguez, I. Andino, Brian Cairns

Publications and Research

In this paper we show how measurements made by a simple handheld polarimeter in conjunction with automated sunsky radiometers can be used to effectively constrain the real part of the complex refractive index of aerosols. We find that even measurements over a limited angular range near 90° scattering angle are sufficient for this purpose. We also note that because of the effect of surface reflectance on the observed degree of linear polarization (DOLP) it is sensible to select spectral bands for these measurements for which the surface is relatively dark and homogeneous (i.e. wavelengths shorter than 700 nm are to …