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Climatic understanding of long-lasting high aerosol concentration episodes and the radiative effect over East Asia : 동아시아 지역에서 장기간 지속되는 에어로졸 고농도 사례와 복사효과에 대한 기후학적 이해

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dc.contributor.advisor허창회-
dc.contributor.author오혜련-
dc.date.accessioned2017-07-14T00:36:19Z-
dc.date.available2017-07-14T00:36:19Z-
dc.date.issued2015-02-
dc.identifier.other000000025051-
dc.identifier.urihttps://hdl.handle.net/10371/121214-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 지구환경과학부, 2015. 2. 허창회.-
dc.description.abstractNo other region in the world is as large and diverse a source of aerosols as the Asian continent. In particular, considerable amounts of air pollutants are generated in China, and the effects of trans-boundary transport of diverse aerosols including air pollutants on human health and regional climate are of multilateral concern in East Asia.
Here, we firstly revealed the mechanism of occurrence and transport for the long-lasting high-PM10 episodes for 13 years (2001–2013) in Seoul, Korea and its link with air pollutants originating in China. Our result show that aerosols originating in China play a major role in the occurrence of multi-day (≥ 4 days) severe air pollution episodes in Seoul, Korea, where the concentration of PM10 exceeds 100 μg m3. Observations show that these multi-day severe air quality episodes occur when a strong high-pressure system resides over the eastern China - Korea region. Such a weather condition confines air pollutants within the atmospheric boundary layer and spread them by slow westerlies within the boundary layer from China into the neighboring countries. These particles lead to air quality deterioration in the short-term perspective, furthermore those result in the change in a radiation properties and an energy budget in the long-term perspective.
Thus, in a climatic sense, we attempted an observationally based estimation of aerosol direct radiatve effect (DRE) for all-sky (both clear- and cloudy-sky) over East Asia (80°E–200°E, 20°N–60°N) for May 2000–December 2005. To reliably estimate all-sky DRE of aerosol over East Asia, we used a combing methodology between the measured a clear sky and the simulated DRE for a cloud sky in each 1°-grid. For the measured clear-sky DRE, we employed aerosol, cloud, and radiation fluxes from the Cloud and Earth's Radiant Energy System (CERES) instrument and the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Terra satellite. For the simulated cloudy-sky DRE, we performed radiative transfer modeling with the MODIS cloud properties in addition to the aerosol optical properties independently estimated in this study that include asymmetry factor and single scattering albedo. The results show that the global mean±standard deviation of DRE for the all-sky scene is −3.57±2.3 W m−2, which is weaker than that for the clear-sky only. This implies that DRE of both total and anthropogenic aerosol is considerably diminished by clouds interrupting solar reflection of aerosols. Particularly, for oceanic area of study domain with optically thick and a large amount cloud, the dimming effect by aerosols is amplified, which results in positive aerosol DRE for all-sky.
Understanding such dynamical processes is a key for advancing the predictability of trans-boundary air pollutants and their health impacts in East Asia as well as developing international measures to improve air quality for the region. And further, evaluation of aerosol DRE for all-sky condition would contribute to reduce the large uncertainty by aerosols over East Asia, which can give some insight to simulate the future climate in model.
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dc.description.tableofcontentsTABLE OF CONTENTS
Abstract 1
Table of Contents 5
List of Figures 7
List of Tables 11
1. Introduction 12
2. Data and model 17
2.1. Satellite observations 17
2.2.1. Clouds and the Earths Radiant Energy System 17
2.2.2. Moderate Resolution Imaging Spectroradiometer 19
2.2.3. Cloud-Aerosol Lidar with Orthogonal Polarization 21
2.2. Ground-based observations 23
2.2.1. Aerosol Robotic Network 23
2.2.2. Particulate matter with a diameter <10 ㎛ (PM10) 24
2.3. Reanalysis data 26
2.3.1. NCEP-NCAR reanalysis data Ⅱ 26
2.4. Radiative transfer model 27
2.4.1. Santa Barbara DISORT Atmospheric Radiative Transfer Model (SBDART) 27
3. Methodology 29
3.1. Definition of aerosol direct radiative effect for clear- and all-sky 29
3.1.1. Aerosol direct radiative effect for clear-sky 29
3.1.2 Aerosol direct radiative effect for all-sky 31
3.2 Estimating aerosol optical properties 33
3.2.1. Retrieval of aerosol single scattering albedo and aerosol asymmetry factor 33
3.3. Estimating aerosol direct radiative effect for all-sky 38
3.3.1. Direct radiative effect of total aerosol for all-sky 38
3.3.2 Direct radiative effect of anthropogenic aerosol for all-sky 46
4. Occurrence and transport mechanism for lasting-day of high PM10 episodes in Seoul 48
4.1. High-PM10 days during 2001–2013: 48
4.1.1 1-day episode vs. multi-day episode 48
4.2. Trans-boundary transport of PM10 from China to Seoul 53
4.2.1 Atmospheric circulation field 53
4.2.2 Station obsevations and backtrjectory analysis 60
4.2.3 Satellite observed aerosol vertical profile 65
4.3. Summary and discussion 68
5. Estimated radiative impact of aerosols for clear- and all-sky 72
5.1. Influencing factors on aerosol radiative effect 72
5.1.1 Aerosol optical depth, aerosol single scattering albedo and aerosol asymmetry factor 72
5.1.2. Cloud fration, cloud top temperature, cloud effective radius, and cloud optical depth 81
5.1.3 Aerosol vertical profile and its frequency above cloud from the CALIOP observation 84
5.2. Direct radiative effect of total and anthropogenic aerosols 90
5.2.1 Direct radiative effect of total aerosol 90
5.2.2 Direct radiative effect of anthropogenic aerosol 96
5.2.3 Validation and assessement of its uncertainty 101
5.3. Summary and discussions 108
6. General conclusions 112
Reference 115
국문초록 127
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dc.formatapplication/pdf-
dc.format.extent3904545 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectAerosol direct radiative effect-
dc.subjectAll-sky-
dc.subjectCloud-
dc.subjectSatellite data-
dc.subjectLong-lasting high PM10-
dc.subjectTransboundary air pollutant-
dc.subject.ddc550-
dc.titleClimatic understanding of long-lasting high aerosol concentration episodes and the radiative effect over East Asia-
dc.title.alternative동아시아 지역에서 장기간 지속되는 에어로졸 고농도 사례와 복사효과에 대한 기후학적 이해-
dc.typeThesis-
dc.description.degreeDoctor-
dc.citation.pages128-
dc.contributor.affiliation자연과학대학 지구환경과학부-
dc.date.awarded2015-02-
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