부산대학교 사범대학 지리교육과 박선엽교수가 오는 7월 23일 APEC 기후센터(APCC)를 방문한다. 박선엽 교수는 “Satellite-Measured Vegetation Phenology and its Relations to Atmospheric Aerosols in the Korean Peninsula”라는 제목으로 오전 11시 APCC 2층에 위치한 에델바이스 회의실에서 세미나를 주재한다.

세미나 일정 등 상세 정보는 아래와 같다.
 

1. 발표자: 박선엽 교수 (부산대학교 사범대학 지리교육과)

2. 발표 제목: Satellite-Measured Vegetation Phenology and its Relations to Atmospheric Aerosols in the Korean Peninsula

3. 일시: 2013년 7월 23일 화요일 오전 11시

4. 장소: APEC 기후센터 에델바이스 회의실 (2층)

5. Abstract

Surface greenness dynamics are associated with the patterns of primary productivity and atmospheric carbon exchange rates on a broad scale (Field et al. 1995; Running et al. 2004; Potter et al. 2007). Vegetation responses to climate change appear strong in Northeast Asia, where diverse forest types and tree species in the region are considered as important carbon sinks. It is reported that Northeastern China and the Korean Peninsula experience significant changes of species composition in forested areas (Jiang et al. 1999). Since atmospheric aerosols play an important role in the interactions between solar radiation and the atmosphere, they are considered one of the key variables in climate modeling (Remer et al. 2005; Lee et al. 2009). High temporal-resolution satellite data can overcome limitations of ground-based phenological studies with reasonable spatial resolution. The objective of this study is to determine the spatiotemporal influences of climatic factors and atmospheric aerosol on phenological cycles of the Korea Peninsular on a regional scale. MODIS Vegetation Index (VI) records allow researchers to create various composites and produce cloud-free, continuous data. MODIS 16-day composites VI data, MOD13Q1, were downloaded from the EROS data center for the 2001-2010 period (https://wist.echo.nasa.gov). In addition to MODIS VI data, aerosol products, MOD08, were analyzed to extract aerosol optical thickness (AOT) over the study area. AOT explains attenuation of sunlight by a column of aerosol, and it serves as a measure of aerosol column concentration (Kaufman et al., 2002).

Spectral analysis, or harmonic analysis, was used to extract major periodic fluctuation signals, or wave forms from the temporal domain of VI data (Azzali and Menenti 2000; Jakubauskas et al. 2001; Moody and Johnson 2001; Park 2009). Any complex raw data collected on a regular basis, such as VI time-series, can be reduced to a series of harmonic terms that have a unique set of amplitude, wavelength, and phase angle. Annual and inter-annual variations and peak points of greenness and AOT signals were analyzed by the technique. Four major forest types, mixed forest, evergreen forest, deciduous forest, and grassland, were selected from ESA GlobCover landuse data (Sophie et al. 2010), and their primary phonological cycles were extracted from the VI time-series. Study results showed that phenological characteristics were similar among evergreen forest, deciduous forest, and grassland, while the inter-annual VI amplitude of mixed forest was differentiated from the other forest types. Forest types with high VI amplitude reached their maximum VI values, but this relationship was not observed within the same forest type. The phase of VI, or the peak time of greenness, was significantly influenced by air temperature. AOT time-series showed strong seasonal and inter-annual variations. Generally, aerosol concentrations were highest from late spring to early summer. However, inter-annual AOT variations did not have significant relationships with those of VIs. Annual variations of AOT, or AOT amplitude, had only weak correlations with surface greenness. The phase of AOT had weak negative correlations with surface greenness. In other words, as AOT concentrations reached earlier in Spring, the VI peak values were observed later over the year. A pixel-based, high resolution study is still required to determine the influences of the characteristics of aerosols (sources, spatial distributions, etc.) on the vegetation phenology in the region.

6. Brief CV

- Education
2003 Ph.D. Geography, University of Kansas, Lawrence, KS, USA
2003 M.A. Geography, Seoul National University
1996 B.A. Geography, Seoul National University

- Academic Positions
2012.09- Associate Professor, Geography Education, Pusan National University
2010-2012.08 Assistant Professor, Geography Education, Pusan National University
2009-2010.08 Assistant Professor, Geoinformatics Engineering, Kyungil University
2004-2009.07 Assistant Professor, Geography & Environmental Sciences, University of Hawaii-Hilo
2004-2009.07 Associate Director, Hawaii Space Grant Consortium, NASA.
2004-2007.07 Program Faculty, Tropical Conservation Biology and Environmental Science (TCBES) Program, University of Hawaii-Hilo
2003-2004 Post-doc Research Fellow, Kansas Applied Remote Sensing Program
1999-2003 Research Assistant/ NASA Earth System Science Fellow, Kansas Applied Remote Sensing Program, University of Kansas
1997-1999 Geodata Technician, Kansas Geological Survey, University of Kansas