Abstract
The bidirectional reflectance distribution function (BRDF) is crucial in determining the quantity of reflected light on the earth’s surface as a function of solar and view angles (i.e., azimuth and zenith angles). The Vegetation and ENvironment monitoring Micro-Satellite (VENµS) provides a unique opportunity to acquire data from the same site, with the same sensor, with almost constant solar and view zenith angles from two (or more) view azimuth angles. The present study was aimed at exploring the view angles’ effect on the stability of the values of albedo and of two vegetation indices (VIs): the normalized difference vegetation index (NDVI) and the red-edge inflection point (REIP). These products were calculated over three polygons representing urban and cultivated areas in April, June, and September 2018, under a minimal time difference of less than two minutes. Arithmetic differences of VIs and a change vector analysis (CVA) were performed. The results show that in urban areas, there was no difference between the VIs, whereas in the well-developed field crop canopy, the REIP was less affected by the view azimuth angle than the NDVI. Results suggest that REIP is a more appropriate index than NDVI for field crop studies and monitoring. This conclusion can be applied in a constellation of satellites that monitor ground features simultaneously but from different view azimuth angles.
Highlights
The Vegetation and ENvironment monitoring Micro-Satellite (VENμS) is an earth observation space mission jointly developed, manufactured, and operated by the NationalCentre for Space Studies (CNES) and the Israel Space Agency (ISA) [1]
TheofL1 product the top of the(VIs) atmosphere reflectance on the3 stability the valuesincluded of vegetation indices and albedo due to with a spatial of under
The current study aimed to explore the effect of the view azimuth angle on two
Summary
The Vegetation and ENvironment monitoring Micro-Satellite (VENμS) is an earth observation space mission jointly developed, manufactured, and operated by the National. The scientific objective of VENμS is to frequently acquire images on 160 preselected sites with a two-day revisit time, a high spatial resolution of 5 m, and 12 narrow bands, ranging from 424 to 909 nm, including four red-edge bands (Table 1). This band setting was designed to characterize vegetation status, monitor water quality in coastal areas and inland waters, and estimate the aerosol optical depth and the water vapor content of the atmosphere. The preselected sites are always observed with constant view azimuth and zenith angles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
