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Measured and modeled radiation fluxes from prairie vegetation at the FIFE study site
Abstract
The purpose of this study was to utilize remotely sensed data, of the type collected by satellite systems, to estimate the incoming and outgoing radiation streams. Estimates of net radiation were then computed from the estimated components and compared to actual measures of net radiation. A Barnes Modular Multiband Radiometer (MMR) model 12-1000 was used to collect bidirectional remotely sensed data at the surface. Models were developed to estimate incoming and reflected shortwave radiation from the MMR data. Estimates of incoming shortwave radiation were compared to measured values and found to be within 40 Wm$\sp{-2}$ in 1987. The 1988 estimates were within 10 Wm$\sp{-2}$. Albedos were estimated to within 4% (absolute) of the measured values in both 1987 and 1988. Statistical analysis revealed a large systematic error which suggests a modeling problem. Use of the albedo algorithm developed in this study is cautioned due to the large systematic error encountered. Several algorithms for estimating incoming longwave radiation were evaluated and compared to actual measures of that parameter. Two of these algorithms (the Brunt model and the modified Deacon equation) produced very reasonable estimates of incoming longwave radiation on a consistent basis. Emitted longwave radiation was calculated with the Stefan-Boltzmann Law from data collected by thermal remote sensing instruments. Net radiation was calculated using the estimated components of the shortwave radiation streams, determined from the algorithms developed in this study, and from the longwave radiation streams provided by the Brunt, modified Deacon, and the Stefan-Boltzmann models. Estimates of net radiation were compared to measured values and found to be within the measurement error of the net radiometers used in the study.
Subject Area
Agronomy|Remote sensing
Recommended Citation
Starks, Patrick James, "Measured and modeled radiation fluxes from prairie vegetation at the FIFE study site" (1990). ETD collection for University of Nebraska-Lincoln. AAI9030155.
https://digitalcommons.unl.edu/dissertations/AAI9030155