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Atmospheric trace gases as probes of chemistry and dynamics

Citation

Li, King-Fai (2013) Atmospheric trace gases as probes of chemistry and dynamics. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:08172012-154924604

Abstract

This dissertation is a collection of empirical and modeling studies focusing on decadal and intraseasonal variabilities in atmospheric tracers. In Part I, a persistent discrepancy between the model and observed stratospheric O3 solar response is revisited using the Whole-Atmosphere Community Chemistry Model (WACCM). The model O3 simulated using UV irradiances measured from the latest spaceborne solar UV measurements by the Solar Radiation and Climate Experiment (SORCE) and that from the solar UV parametrization developed by the Naval Research Laboratory (NRL) are studied and compared with observations. None of the simulations using SORCE and NRL UV simultaneously agree with the observed O3 solar response in both upper and lower stratospheres, thus presenting a dilemma to our current understanding of stratospheric O3 response to UV perturbations. However, the simulation using the SORCE UV irradiance leads to a solar response in upper stratospheric/lower mesospheric OH column that agrees better than those derived from ground-based and satellite observations. Continuous long-term observations of solar UV, OH, O3, and other related chemical species through upcoming solar cycles are crucial for further investigations to solve the above puzzles. In Part II, intraseasonal variabilities in upper tropospheric/lower stratospheric (UTLS) O3 and mid-tropospheric carbon dioxide (CO2) related to the Madden-Julian oscillation (MJO) are studied using recent satellite observations. The UTLS O3 at mid-latitudes is shown to be modulated by the MJO through dynamical motions of the tropopause layer, supporting the conjecture proposed in previous studies. It is further shown that the UTLS O3 over the Arctic can be also modulated by the tropopause motions through MJO teleconnections. On the other hand, the distribution of tropical mid-tropospheric CO2 is modulated by the MJO through upward transport of surface CO2. The amplitude is of critical scale for identifying oceanic and land sources of CO2. The detailed structures of these MJO impacts are useful for diagnosing chemical transport models. These findings may be useful for improving air quality forecasts to weekly/monthly timescales, which help warn the public in advance and help authorities to take efficient emergency control actions.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:solar cycle, tropical intraseasonal variability, ozone, carbon dioxide, hydroxyl radical, ultraviolet
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Environmental Science and Engineering
Awards:Jack Eddy Postdoctoral Fellowship (University Corporation for Atmospheric Research/National Aeronautics and Space Administration)
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Yung, Yuk L.
Thesis Committee:
  • Ingersoll, Andrew P. (chair)
  • Blake, Geoffrey A.
  • Bordoni, Simona
  • Yung, Yuk L.
Defense Date:2 August 2012
Author Email:kfli2004 (AT) hotmail.com
Funders:
Funding AgencyGrant Number
National Aeronautics and Space AdministrationP1095255
National Science Council, Taiwan98-2111-M-001-014-MY3
National Science FoundationATM-0840787
National Science FoundationATM-0840755
National Science FoundationATM-0934303
National Science FoundationATM-0840755
Record Number:CaltechTHESIS:08172012-154924604
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:08172012-154924604
Related URLs:
URLURL TypeDescription
http://www.gps.caltech.edu/~kflAuthorAuthor website
http://dx.doi.org/10.5194/acpd-12-1867-2012DOIArticle adapted for ch. 2
http://dx.doi.org/10.5194/acp-12-425-2012DOIArticle adapted for ch. 5
http://dx.doi.org/10.1073/pnas.1008222107 DOIArticle adapted for ch. 7
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7186
Collection:CaltechTHESIS
Deposited By: Dr. King-Fai Li
Deposited On:23 Aug 2012 23:38
Last Modified:09 Jan 2014 22:45

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