Intercepted Photosynthetically Active Radiation Estimated by Spectral Reflectance
نویسندگان
چکیده
Interception of photosynthetically active radiation (PAR) was evaluated relative to greenness and normalized difference [MSS (7 5)/(7 + 5)] for five planting dates of wheat for 1978-79 and 1979-80 at Phoenix, Arizona. Intercepted PAR was calculated from leaf area index and stage of growth. Linear relationships were found with greenness and normalized difference with separate relationships describing growth and senescence of the crop. Normalized difference was significantly better than greenness for all planting dates. For the leM area growth portion of the season the relation between PAR interception and normalized difference was the same over years and planting dates. For the leaf senescence phase the relationships showed more variability due to the lack of data on light interception in sparse and senescing canopies. Normalized difference could be used to estimate PAR interception throughout a growing season.
منابع مشابه
Modelling and measurement of radiation interception by olive canopies
We present the formulation, calibration and validation of a model to estimate photosynthetically active radiation (PAR) intercepted by olive (Olea europaea L.) canopies. The model calculates the PAR transmittance at any point located within the four central trees of the orchard. The spatial and time integration of this process allows calculation of PAR transmitted to the ground and, thus, the P...
متن کاملMaize yield potential: critical processes and simulation modeling in a high-yielding environment
Understanding processes of maize (Zea mays L.) growth and production of grain in highyielding, irrigated conditions offers hope to understand yield potential in many other environments. In this study we investigated such processes at the plant level, and attempted to simulate maize yields at the field level and county level in the high yielding region of the High Plains of Texas. In addition, w...
متن کاملSynergistic algorithm for estimating vegetation canopy leaf area index and fraction of absorbed photosynthetically active radiation from MODIS and MISR data
A synergistic algorithm for producing global leaf area index and fraction of absorbed photosynthetically active radiation fields from canopy reflectance data measured by MODIS (moderate resolution imaging spectroradiometer) and MISR (multiangle imaging spectroradiometer) instruments aboard the EOS-AM 1 platform is described here. The proposed algorithm is based on a three-dimensional formulatio...
متن کاملMaize Radiation Use Efficiency under Optimal Growth Conditions
and Amthor (1999) suggested that the RUE era in crop modeling should be closed. Accurate measurement of crop growth and radiation use efficiency A number of factors contribute to the variation in (RUE) under optimal growth conditions is required to predict plant reported estimates of RUE (Sinclair and Muchow, 1999). dry matter accumulation and grain yield near the genetic growth potential. Rese...
متن کاملEstimation of Incident Photosynthetically Active Radiation From Moderate Resolution Imaging Spectrometer Data
[1] Incident photosynthetically active radiation (PAR) is a key variable needed by almost all terrestrial ecosystem models. Unfortunately, the current incident PAR products estimated from remotely sensed data at spatial and temporal resolutions are not sufficient for carbon cycle modeling and various applications. In this study, the authors develop a new method based on the look-up table approa...
متن کامل