DOI

10.17077/etd.dhrv2zrr

Document Type

Thesis

Date of Degree

Spring 2018

Access Restrictions

Access restricted until 07/03/2019

Degree Name

MS (Master of Science)

Degree In

Chemical and Biochemical Engineering

First Advisor

Jun Wang

First Committee Member

Gregory R. Carmichael

Second Committee Member

Charles O. Stanier

Abstract

Spatial distribution of diurnal variations of aerosol properties in South Korea, both long term and short term, is studied by using 9 AERONET sites from 1999 to 2017 for long-term averages and from an additional 10 sites during the KORUS-AQ field campaign. The extent to which WRF-Chem model and the GOCI satellite retrieval can describe these variations is also analyzed. In daily average, Aerosol Optical Depth (AOD) at 550 nm is 0.386 and shows a diurnal variation of +20 to -30% in inland sites, respectively larger than the counterparts of 0.308 and ± 20% in coastal sites. Both the inland and coastal sites have their diurnal variation peaks in the early morning and in the evening with noontime and early afternoon valleys. In contrast, Angstrom exponent values in all sites are between 1.2 and 1.4 with the exception of the inland rural sites having smaller values near 1.0 during the early morning hours. All inland sites experience a pronounced increase of Angström Exponent from morning to evening, reflecting overall decrease of particle size in daytime. To statistically obtain the climatology of diurnal variation of AOD, a minimum of requirement of ~2 years of observation is needed in coastal rural sites, twice more than the urban sites, which suggests that diurnal variation of AOD in urban setting is distinct and persistent. AERONET, GOCI, WRF-Chem, and observed PM2.5 data consistently show dual peaks for both AOD and PM2.5, one at ~ 10 KST and another ~14 KST. While Korean GOCI satellite is able to consistently capture the diurnal variation of AOD, WRF-Chem clearly has the deficiency to describe the relatively change of peaks and variations between the morning and afternoon, suggesting further studies for the diurnal profile of emissions. Overall, the relative small diurnal variation of PM2.5 is in high contrast with large AOD diurnal variation, which suggests the need to use AOD from geostationary satellites for constrain either modeling or analysis of surface PM2.5 for air quality application.

Keywords

aerosol, aerosol optical depth, air quality, korea, particulate matter, wrf-chem

Pages

viii, 44 pages

Bibliography

Includes bibliographical references (pages 41-44).

Copyright

Copyright © 2018 Elizabeth Marie Lennartson

Available for download on Wednesday, July 03, 2019

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