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Full-Text Articles in Physical Sciences and Mathematics
Characterization Of Firn Microstructure Using Scanning Electron Microscopy: Implications For Physical Properties Measurements And Climate Reconstructions, Nicole Spaulding
Characterization Of Firn Microstructure Using Scanning Electron Microscopy: Implications For Physical Properties Measurements And Climate Reconstructions, Nicole Spaulding
Electronic Theses and Dissertations
Samples from 12 East Antarctic firn and ice cores were analyzed using scanning electron micrcoscopy (SEM) in order to first develop a technique for the accurate characterization of physical properties and then to investigate the relationship between the physical microstructure and chemical properties. Both physical properties, such as grain size and porosity, and chemical properties, such as major ion and trace element concentration, provide information about atmospheric temperature changes, impurity content, accumulation rate and deformation history; therefore the characterization of both types of properties is necessary. Further, knowledge of the relationship between the physical and chemical properties may increase our …
A 200-Year Sulfate Record From 16 Antarctic Ice Cores And Associations With Southern Ocean Sea Ice Extent, Daniel A. Dixon
A 200-Year Sulfate Record From 16 Antarctic Ice Cores And Associations With Southern Ocean Sea Ice Extent, Daniel A. Dixon
Electronic Theses and Dissertations
Data from sixteen, 50m- to 115m-deep, sub-annually dated ice cores are used to examine the recent spatial and temporal concentration variability of sea salt (ss)S04 " and excess (xs)S04 " over West Antarctica for the last 200 years. The preservation of seasonal layers throughout the length of each record results in a dating accuracy of better than one year based on known global scale volcanic events. A dual transport source for West 9 9 Antarctic SSSO4 " and XSSO4 " is observed: lower tropospheric for areas below 1000m elevation and mid-upper tropospheric/stratospheric for areas located above 1000m. The XSSO4 " …
Modeling Bird Species Occurrence In Current And Future Landscapes, Stephen Nicholas Matthews
Modeling Bird Species Occurrence In Current And Future Landscapes, Stephen Nicholas Matthews
Electronic Theses and Dissertations
With mounting evidence that global temperatures have increased significantly over the last century and the projections of greater changes in climate by the end of this century, understanding the potential consequences of these changes for species is essential to conservation efforts. Here I evaluate the potential response of birds to projected climate change by using regression tree analysis to create models of species distributions under current conditions from Breeding Bird Survey data and then project these models onto General Circulation Model (GCM) scenarios of global climate change. Before modeling species responses to climate change, I selected seventeen bird species to …