Synergistic algorithm for estimating vegetation canopy leaf area index and fraction of absorbed photosynthetically active radiation from MODIS and MISR data

TLDR

The study builds on theoretical foundations of radiative transfer in vegetation canopies. The paper introduces a synergistic algorithm to estimate global leaf area index and absorbed photosynthetically active radiation from MODIS and MISR canopy reflectance data. The algorithm uses a 3‑D radiative transfer formulation, integrating MODIS single‑angle, up to seven spectral bands and MISR nine‑angle, four spectral band data, and applies reactor theory to split the problem into two subproblems solved via a look‑up table.

Abstract

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 formulation of the radiative transfer process in vegetation canopies. It allows the use of information provided by MODIS (single angle and up to 7 shortwave spectral bands) and MISR (nine angles and four shortwave spectral bands) instruments within one algorithm. By accounting features specific to the problem of radiative transfer in plant canopies, powerful techniques developed in reactor theory and atmospheric physics are adapted to split a complicated three‐dimensional radiative transfer problem into two independent, simpler subproblems, the solutions of which are stored in the form of a look‐up table. The theoretical background required for the design of the synergistic algorithm is discussed.