Year-end Sale % OFF 
Abstract
In this study, the Visible Infrared Imaging Radiometer Suite (VIIRS) Enhanced Vegetation Index (EVI) was spectrally cross-calibrated with the Moderate Resolution Imaging Spectroradiometer (MODIS) EVI using a year-long, global VIIRS-MODIS dataset at the climate modeling grid (CMG) resolution of 0.05°-by-0.05°. Our cross-calibration approach was to utilize a MODIS-compatible VIIRS EVI equation derived in a previous study [Obata et al., J. Appl. Remote Sens., vol.7, 2013] and optimize the coefficients contained in this EVI equation for global conditions. The calibrated/optimized MODIS-compatible VIIRS EVI was evaluated using another global VIIRS-MODIS CMG dataset of which acquisition dates did not overlap with those used in the calibration. The calibrated VIIRS EVI showed much higher compatibility with the MODIS EVI than the original VIIRS EVI, where the mean error (MODIS minus VIIRS) and the root mean square error decreased from −0.021 to −0.003 EVI units and from 0.029 to 0.020 EVI units, respectively. Error reductions on the calibrated VIIRS EVI were observed across nearly all view zenith and relative azimuth angle ranges, EVI dynamic range, and land cover types. The performance of the MODIS-compatible VIIRS EVI calibration appeared limited for high EVI values (i.e., EVI > 0.5) due likely to the maturity of the VIIRS dataset used in calibration/optimization. The cross-calibration methodology introduced in this study is expected to be useful for other spectral indices such as the normalized difference vegetation index and two-band EVI.
Highlights
Biophysical parameters retrieved from Earth observation data are crucial for improving our understanding of biosphere–atmosphere interactions (e.g., [1])
We evaluated the extent to which errors decreased by applying the obtained Visible Infrared Imaging Radiometer Suite (VIIRS) enhanced vegetation index (EVI) equation with the optimized coefficients on global data and the degree to which errors varied as a function of sun-target-sensor viewing geometry, EVI values, and land cover type
The Moderate Resolution Imaging Spectroradiometer (MODIS)-compatible VIIRS EVI was obtained via cross-calibration using a year-long global dataset (MODIS and VIIRS climate modeling grid (CMG)) and was subsequently evaluated with an additional dataset not used for the calibration/optimization
Summary
Biophysical parameters retrieved from Earth observation data are crucial for improving our understanding of biosphere–atmosphere interactions (e.g., [1]). Spectral vegetation indices (VIs) derived from remotely sensed data have been used successfully to estimate biophysical parameters, for example, the fraction of photosynthetically active radiation (FAPAR), leaf area index (LAI) [2], and green vegetation fraction [3]. The enhanced vegetation index (EVI), developed for Moderate Resolution Imaging Spectroradiometer (MODIS) of the National Aeronautics and Space Administration’s (NASA) Earth Observing System (EOS), was designed to optimize the vegetation signal with improved sensitivity in high biomass regions and improved vegetation monitoring through a decoupling of the canopy background signal and a reduction in atmospheric aerosol influences that affect the NDVI [7]: EVI “ G ρ nρr ρn C1 ρr C2 ρb L (1)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
