Shi, Guochun (2025). Investigating the variability of polar ozone and water vapor in the middle atmosphere and their impacts on the mesospheric dynamics. (Thesis). Universität Bern, Bern
|
Text
25shi_g.pdf - Thesis Available under License Creative Commons: Attribution (CC-BY 4.0). Download (57MB) | Preview |
Abstract
This thesis is dedicated to investigating the interannual and small-scale variability of ozone and water vapor in the Arctic middle atmosphere using ground-based microwave radiometers GRound-based Ozone MOnitoring System for Campaigns (GROMOS-C) and MIddle Atmospheric WAter vapor RAdiometer for Campaigns (MIAWARA-C), located at Ny-Ålesund, Svalbard (78.99◦N, 12◦E). These measurements provide continuous observations over an altitude range covering 20 to 75 km, offering valuable insights into atmospheric dynamics and chemical processes by comparing with reanalysis and satellite datasets. Furthermore, by integrating Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X) model simulations with meteor radar observations, this study examines the radiative effects of ozone and water vapor on mesospheric dynamics. This combined approach enhances our understanding of the complex interactions between radiative forcing, atmospheric waves, and circulation patterns in the Arctic middle atmosphere. Chapter 1 provides an overview of the structure and dynamics of the Arctic middle atmosphere. It introduces the key large-scale circulation patterns, including the polar vortex, the Brewer-Dobson Circulation (BDC), and Sudden Stratospheric Warming (SSW) events, which play a crucial role in atmospheric variability. The chapter also examines the influence of planetary waves and atmospheric tides on middle atmospheric dynamics. Furthermore, it discusses the role of ozone and water vapor in the Arctic middle atmosphere, emphasizing their interactions with atmospheric circulation and radiative processes. Finally, the chapter presents key measurement techniques and modeling approaches for studying middle atmospheric dynamics and composition. Chapter 2 d escribes t he d atasets u sed i n t his s tudy, f ocusing o n ground-based and satellite observations as well as model simulations. It first introduces ground-based microwave measurements, including the principles of microwave remote sensing and the specific instruments GROMOS-C and MIAWARA-C, which provide continuous observations of ozone and water vapor in the Arctic middle atmosphere. Next, it presents integrated ozone and water vapor datasets from Aura Microwave Limb Sounder (MLS), the Modern-Era Retrospective Analysis for Research and Applications (MERRA)-Version 2 reanalysis, and the Specified Dynamics (SD) WACCM-X model, highlighting their relevance for studying atmospheric variability. Finally, the chapter discusses meteor radar observations, effectively capturing tidal activity in the Mesosphere and lower Thermosphere (MLT). The aim and impact of this thesis are presented in chapter 3, which outlines how the thesis contributes to the broader scientific understanding and the specific role of the project in advancing the study. Chapter 4 presents ozone and water vapor variability in the polar middle atmosphere observed with ground-based microwave radiometers. Chapter 5 examines the dynamical and chemical processes in response to polar ozone anomalies during major SSW and early final stratospheric warming events. Chapter 6 presents new insights into the polar ozone and water vapor, radiative effects, and their connection to the tides in the mesosphere-lower thermosphere during major SSW events. Finally, Chapter 7 summarizes the conclusions of this thesis and provides an outlook on potential future research directions.
| Item Type: | Thesis |
|---|---|
| Dissertation Type: | Cumulative |
| Date of Defense: | 8 July 2025 |
| Subjects: | 500 Science > 530 Physics |
| Institute / Center: | 08 Faculty of Science > Institute of Applied Physics 10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR) |
| Depositing User: | Hammer Igor |
| Date Deposited: | 04 Sep 2025 06:51 |
| Last Modified: | 04 Sep 2025 06:59 |
| URI: | https://boristheses.unibe.ch/id/eprint/6651 |
Actions (login required)
 |
View Item |