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EO-1 Hyperion capturing seasonal dynamics in vegetation phenology and spectral properties, associated with CO2 uptake in three different ecosystems
Petya
Krasteva Entcheva
Campbell, NASA GSFC/JCET/UMBC, petya.campbell@nasa.gov
(Presenter)
Spatial heterogeneity and seasonal dynamics in vegetation physiology contribute significantly to the uncertainties in regional and global CO2 budgets. Satellite remote sensing is essential for monitoring vegetation physiology and spatial variation, to assess the impact of terrestrial ecosystems on the dynamics of carbon fluxes and improve our understanding of the underlying factors. High spectral resolution measurements (≤10 nm, 400-2500 nm) provide the optimal tool for synoptic evaluation of many of the factors affecting the ability of the vegetation to sequester carbon and to reflect radiation, due to changes in vegetation pigment and water content, structural and chemical composition. This study focuses on the analysis of EO-1 Hyperion data in comparison to CO2 flux estimates at three vastly different vegetative sites (Mongu, Duke and Konza), representing major vegetation types (e.g. hardwood forest, grassland, evergreen forest, savanna). Our goal is to assess the temporal dynamics in vegetation spectra at these sites, seeking common spectral trends (spectral bio-indicators) associated with vegetation function, induced by the seasonal effects/variation of temperature, moisture and humidity. EO-1 Hyperion seasonal composites were assembled and the radiance data was corrected for atmospheric effects to surface reflectance using the Atmosphere CORrection Now (ACORN) model. Reflectance spectra were collected in the flux towers footprints, and utility of spectral indicators of vegetation physiology were computed and compared to field flux tower measurements (e.g., CO2 flux, µmol m-2 s-1). Spectral signatures significantly differed based on vegetation type and site specific phenology. Our preliminary results suggest a strong correlation between CO2 flux and a number of bio-indicators associated with pigment content (r=0.77--0.86; using 670-790 nm region), regardless of vegetation type and site. This study will further be expanded to other vegetation types and sites (FLUX and LTER) to test the ability of the established spectral indicators of vegetation function to capture the dynamics in vegetation phenology and estimate CO2 fluxes. Presentation: 2011_Poster_Campbell_311_358.gif (2522k) Presentation Type: Poster Session: Global Change Impact & Vulnerability (Tue 11:30 AM) Associated Project(s):
Poster Location ID: 311
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