A Comparison of Normalized Difference Vegetation Indices from Geostationary and Low Earth Orbiting Satellites

This study compares Normalized Difference Vegetation Index (NDVI) from the Advanced Himawari Imager (AHI) with Moderate Resolution Imaging Spectroradiometer (MODIS) over Australia.  Measurements from geostationary satellites provide improved cloud-free coverage of land observations compared to Low Earth Observing (LEO) satellites due to more frequent temporal refresh, especially in tropical areas.  LEO observations are influenced by variation in look angle as the orbits shift from day to day, whereas geostationary observations are influenced by changes in solar zenith angle throughout the day.  These bidirectional reflectances are also dependent upon the land cover type and phenology. NDVI were also compared with satellite-based soil moisture measurements.  Results show weekly maximum NDVI composites from AHI were higher than those from MODIS.  Variations in NDVI among different land cover types and view geometry are presented here which provides guidance on optimum data selection criteria for generating these composites from geostationary satellites.