Multiangle remote sensing: Past, present and future

Abstract

Multiangle remote sensing has many new and important applications in the study of the earth's land, ocean, and atmosphere. For land studies, multiangle remote sensing samples the bidirectional reflectance distribution function (BRDF) of land surfaces. The modeling and observation of land surface BRDFs has thus been an area of active research for the past decade. The International Forum on BRDF (IFB) was organized in December, 1998, in San Francisco to summarize recent progress in BRDF research, and to identify important future research topics and determine their priorities. This special issue of Remote Sensing Reviews presents a series of summary papers outlined at the IFB that focus on specific BRDF research areas. This paper provides an overview of the special issue by summarizing IFB discussions and individual papers. It also presents five primary courses of action for the BRDF community identified during the IFB. These include (1) identifying a set of key scientific questions to which multiangle remote sensing provides a qualitative and quantitative advances over more traditional approaches, as well as organizing case studies to show the value added by multiangle remote sensing; (2) exploring different inversion techniques, including data fusion and assimilation, to estimate land surface variables that are highly relevant to climate, environmental and ecological studies; (3) continuing the development of simpler BRDF models for analyzing satellite observations; (4) developing a benchmark validation database; and (5) strengthening graduate education program and outreach activities.