IN11E-1798
Utilizing a Tower Based System for Optical Sensing of Ecosystem Carbon Fluxes

Monday, 14 December 2015
Poster Hall (Moscone South)
Karl F Huemmrich1, Lawrence A Corp2, Elizabeth Middleton3, Petya K. E. Campbell1, David Landis3 and William P Kustas4, (1)University of Maryland Baltimore County, Baltimore, MD, United States, (2)Sigma Space Corporation, Lanham, MD, United States, (3)NASA Goddard Space Flight Cen., Greenbelt, MD, United States, (4)USDA Agricultural Research Service New England Plant, Soil and Water Research Laboratory, East Wareham, MA, United States
Abstract:
Optical sampling of spectral reflectance and solar induced fluorescence provide information on the physiological status of vegetation that can be used to infer stress responses and estimates of production. Multiple repeated observations are required to observe the effects of changing environmental conditions on vegetation. This study examines the use of optical signals to determine inputs to a light use efficiency (LUE) model describing productivity of a cornfield where repeated observations of carbon flux, spectral reflectance and fluorescence were collected. Data were collected at the Optimizing Production Inputs for Economic and Environmental Enhancement (OPE3) fields (39.03°N, 76.85°W) at USDA Beltsville Agricultural Research Center. Agricultural Research Service researchers measured CO2 fluxes using eddy covariance methods throughout the growing season. Optical measurements were made from the nearby tower supporting the NASA FUSION sensors. The sensor system consists of two dual channel, upward and downward looking, spectrometers used to simultaneously collect high spectral resolution measurements of reflected and fluoresced light from vegetation canopies at multiple view angles. Estimates of chlorophyll fluorescence, combined with measures of vegetation pigment content and the Photosynthetic Reflectance Index (PRI) derived from the spectral reflectance are compared with CO2 fluxes over diurnal periods for multiple days. The relationships among the different optical measurements indicate that they are providing different types of information on the vegetation and that combinations of these measurements provide improved retrievals of CO2 fluxes than any index alone