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Browsing by Subject "Paleoclimate science"
Now showing items 1-19 of 19
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A window into terrestrial paleoclimate: soil carbonate formation processes and climate proxy applications
The isotopic composition of pedogenic (formed in soil) carbonates provides a geologically abundant archive of terrestrial climate change and the interactions between Earth’s climate, geologic, and biologic systems. However, ... -
Beautiful Days in the Neighborhood: Modeling Self-Perpetuated Climate and Forest Expansion during the Mid-Holocene
At the end of glacial periods, warmer temperatures induce ice sheet retreat, exposing the land surface for forest establishment. The emergence of forest transforms the area from high to low albedo. Lowering land surface ... -
Climate driven changes in nitrate deposition and preservation over the West Antarctic Ice Sheet
Nitrate preserved in ice core records has the potential to be used as a proxy for historic atmospheric NO x concentrations and oxidant abundances. Nitrate deposited to ice sheets can undergo photolysis to NO x , oxidation, ... -
Climate dynamics revealed in ice cores: advances in techniques, theory, and interpretation
Ice cores from the polar ice sheets provide detailed histories of Earth's climate. Interpreting past climate dynamics from ice-core records requires understanding how the climate system influences the geochemical proxies ... -
Climate reconstructions from ice cores: New techniques to understand the information preserved in the South Pole ice core
Polar ice cores preserve information about past changes in climate and ice dynamics. Studying changes that have occurred in the past improves understanding of Earth's climate system. Large climate changes, such as the most ... -
Fundamental controls on triple oxygen-isotope ratios in Antarctic precipitation and ice cores
Stable isotope ratios of water (δD and δ18O) in polar precipitation and ice cores have long been used to study past climate variations and the hydrological cycle. Recently-developed methods permit the precise measurement ... -
Growth, chamber formation, and microscale heterogeneity in planktic foraminifera: Implications for paleoclimate proxies
The calcite tests of planktic foraminifera contain a number of geochemical proxies, which are often used to determine past ocean conditions. However, the incorporation of these proxies into the test is often affected by ... -
Hydrogen Isotopes from Lipid Biomarkers: Purification, Field Calibration, and Application to Reconstructing Galapagos Paleohydrology
(2013-11-14)The tropics are centrally important in determining global climate patters as the primary heat and moisture source for atmosphere and ocean circulation. Understanding of the range of natural variability and the sensitivity ... -
Investigating the drivers of glacier retreat in West Antarctica using proxy-data assimilation and numerical modeling
Outlet glaciers in West Antarctica are rapidly retreating and contributing to sea level rise. Ice loss is primarily occurring via wind-driven incursions of warm circumpolar deep water melting the ice shelves that buttress ... -
Isotopic investigation of anthropogenic- and climate-driven changes in sulfate and nitrate aerosol production
(2013-11-14)The oxygen triple-isotopic composition (Δ<super>17</super>O) of sulfate or nitrate provides insight into the relative importance of the different pathways that lead to their formation in the atmosphere, with implications ... -
Mechanisms of Tropical Pacific Climate Change During the Holocene
A novel set of hydroclimate reconstructions is presented from the eastern equatorial Pacific that spans the last 9100 years. Past changes in total climatological rainfall and rainfall associated with El Niño events were ... -
The Paleocene Eocene Thermal Maximum in the Hanna Basin, WY: Constraints from Organic Carbon Isotopes and Palynological Data
(2014-02-24)The P-E boundary, approximately 56 Ma, coincides with a global climatic event, the Paleocene-Eocene Thermal Maximum (PETM). The PETM is believed to have resulted from a 2-8 fold increase in atmospheric pCO2 in less than ... -
Quantifying changes in climate and surface elevation of polar ice sheets during the last glacial-interglacial transition
This dissertation describes three research projects investigating changes in polar climate and the ice sheets during the last deglaciation. The first project, Chapter 2, reconstructs the past 20,000 years of Greenland ... -
Quantifying the deep: The importance of diagenetic reactions to marine geochemical cycles
Marine sediments play a fundamental role in long-term element cycles on Earth and host an expansive microbial ecosystem known as the “oceanic deep biosphere”. The biogeochemical and inorganic reactions that occur in the ... -
Quaternary glaciation in Central Asia
The mountain ranges in Central Asia were heavily glaciated during the Quaternary Period. The relative magnitudes of paleoglaciers varied spatially and temporally. The chronology of glacial standstills was established from ... -
Reconstructing Coupled Atmosphere-Ocean Variability Over the Last Millennium
Coupled interactions between oceans and the atmosphere are fundamental to low-frequency variability of the Earth System. While the instrumental record provides an account of this coupled variability over time, the length ... -
Reconstructing Past Climate by Using Proxy Data and a Linear Climate Model
In this work we improve the skill of climate field reconstructions (CFRs) through the use of an online paleoclimate data assimilation (PDA) method within the Last Millennium Reanalysis framework (LMR). A computationally ... -
Tropical paleoclimate reconstructions from stable isotopes of mangrove lipid biomarkers
Tropical oceans play an integral role in global climate dynamics, yet past tropical hydrologic variability is poorly constrained, as many established climate proxies are better suited to higher latitudes. Hydrogen isotope ... -
Tropical South Pacific Paleohydrology from Hydrogen Isotopes in Algal Lipids
The tropics play a central role in global atmospheric moisture transport, however paleoclimate records of tropical precipitation are relatively scarce. Reconstructing pre-instrumental hydrological change requires the use ...