The JERS-1 Amazon Multi-Season Mapping Study (JAMMS): Science Objectives and Implications for Future Missions Anthony Freeman, Bruce Chapman, Paul Siqueira Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive Pasadena, California 9 1 109 Tel: (818) 354 1887 Fax: (818) 393 5285 e-mail: tony.freeman@pl.nasa.gov Abstract In late September 1995, the National Space Development Agency of Japan (NASDA) began a new phase of operations for the Japanese Earth Remote Sensing satellite (JERS-1) Synthetic Aperture Radar (SAR) - the Global Rain Forest Mapping (GRFM) project. The first rain forest area to be mapped was the Amazon Basin, between September and November of that year (the low flood season for much of the region), in support of the JERS-1 Amazon Multi-season Study (JAMMS), sponsored by NASA. This data acquisition was repeated six months later to acquire a second map of the Amazon, during the high flood season in May/June of 1996.The main objective of the JAMMS project was to generate a map of inundation over the Amazon basin by comparing data from the high- and low-flood seasons. Most of the data collected during these two phases of the JAMMS project, a total of -5000 frames of data, was received and processed by the Alaska SAR Facility, then sent to JPL and NASDA for post-processing and analysis. The quality of the data processed by ASF for the JAMMS project has proved to be exceptional. This paper is a summary of the JAMMS project, which has resulted in a scientific data set of very high value - a multi-season snapshot of one of themost difficult areas on Earth to monitor. I. Introduction The Amazon rain forest is a region of the earth that is undergoing rapid change. Man-made disturbance such as clear cutting for agriculture or mining is altering the rain forest ecosystem. For many parts of the rain forest, seasonal changes from the wet to the dry season are also significant and fundamental to understanding the regional ecology. Changes in the seasonal cycle of flooding and draining can cause significant alterations in the forest ecosystem. Because much of the Amazon basin is regularlycovered by thick clouds, optical and infrared coverage from the LANDSAT and SPOT satellites is sporadic. Imaging radar offers a much better potential for regular monitoring of changes in this region. In particular, the JERS-1 satellite carried an L- band HH SAR system which, via an on-board type recorder, could collect data from almost anywhere on the globe, at any time of year.