Graduation Semester and Year
2023
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Earth and Environmental Science
Department
Earth and Environmental Sciences
First Advisor
Melanie Sattler
Abstract
The Paleocene-Eocene Thermal Maximum (PETM, ~56 my ago, 170,000y event) is characterized by a negative δ13C excursion into the atmosphere. This event caused global temperature to increase by about 5-6 °C, followed by climate responses such as marine acidification, ocean stratification, shoaling of calcite compensation depth (CCD), stronger hydrological cycle, and significant changes in marine ecosystems. It is one of the very few analogies of today’s global warming climate and thus is valuable to study. It still holds much potential for research, including using the state-of-the-art model CESM1.2. Proxy records are limited due to the nature of geological preservation and tectonic evolution. Modeling and simulations can provide insights to supplement the limited proxy records research. Here, we explore the seasonality, hydrological cycles, and controlling factors of their changes from pre-PETM to the PETM in the first paper; the ability of CESM1.2 to simulate carbonate chemistry, changes in lysocline and CCD in the Atlantic Ocean in the second paper; and the shift of phytoplankton functional groups, using the same preferendum to capture first-hand reactions to environmental changes, from pre-industrial pCO2 to pre-PETM in the third paper. All papers use CESM1.2 simulation results with or without BEC. Our results show that from pre-PETM to PETM, seasonality increases in mid-latitude continental interiors and decreases in high and low latitudes, along with globally enhanced moisture transfer in hydrological cycles. The main controlling factors of these areas are snow-albedo effect, soil moisture, and precipitation. CESM1.2 and ocean Biogeochemical (BGC) Elemental Cycling (BEC) can simulate the changes of carbonate chemistry of the Atlantic Ocean, with certain modifications in the code base and without the need of extra models. There are noticeable and significant changes in chlorophyll, nutrient and NPP from PETM in pre-industrial pCO2 and pre-PETM, but distinct variations from pre-industrial and PETM in pre-industrial pCO2 simulations. Proxy record scarcity is the main limitation of the studies on PETM and should be used with care. In the meantime, machine learning is encouraged for multi-disciplinary research of complicated topics such as carbon chemistry and phytoplankton functional group preferendum and ecosystem dynamics.
Keywords
CESM1.2, PETM, Seasonality, Seasonal hydrological cycle, Carbonate chemistry, Phytoplankton functional groups
Disciplines
Earth Sciences | Physical Sciences and Mathematics
License
This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.
Recommended Citation
Wang, Jiayi, "A GLIMPSE INTO THE CLIMATE, SEASONALITY, HYDROLOGICAL CYCLE, CARBONATE CHEMISTRY AND MARINE ECOSYSTEM SHIFT OF THE PRE-PETM AND THE PETM USING NCAR CESM1.2" (2023). Earth & Environmental Sciences Dissertations. 66.
https://mavmatrix.uta.edu/ees_dissertations/66
Comments
Degree granted by The University of Texas at Arlington