THE GLOBAL RAIN FOREST MAPPING PROJECT BY JERS-1 SAR 
Àke Rosenqvist 
Earth Observation Center 
National Space Development Agency of Japan 
1401 Numanoue, Ohashi, Hatoyama-machi 
Hiki-gun, Saitama 350-03, Japan 
Commission VII, Working Group 10 
KEY WORDS: SAR, Global, Environment, Monitoring, Mosaic 
ABSTRACT: 
The Global Rain Forest Mapping project by JERS-1 SAR (GRFM) is an effort by NASDA, in cooperation 
with, among others; the Earth Remote Sensing Data Analysis Center of Japan (ERSDAC), the National Aeronautics and 
Space Administration (NASA), the Jet Propulsion Laboratory (JPL), the Alaska SAR Facility (ASF), the Joint Research 
Centre of the E.C. (JRC), the National Institute for Space Research of Brazil (INPE), the National Institute for 
Amazonian Research of Brazil (INPA) and the University of California Santa Barbara (UCSB) to acquire contiguous SAR 
data sets of the major rain forest areas on the Earth by the L-band SAR on JERS-1. The areas that have been, or are to 
be, covered within the project are the entire Amazon Basin, from the Atlantic to the Pacific, central and west Africa, from 
the eastern coast of Kenya to Sierra Leone in the west, and South-East Asia, including Papua New Guinea. The GRFM 
project covers a total area of about 40 million km2, corresponding to some 10,000 scenes, or 1.2 Terra byte of data that 
is to be processed. ; 
The output of the GRFM project will be regional SAR image mosaics at 100 meter resolutions, semi-continental mosaics 
at 400 meter resolutions and coarse classifications over certain areas. Mosaics and classifications will be available to 
the scientific community for non-commercial purposes on CD-ROMs. 100 meter resolution non-mosaicked images will be 
made available on the Internet. 
1. INTRODUCTION wave band and the on-board Mission Data Recorder. 
JERS-1 was launched by NASDA and MITI (the Ministry of 
1.1 Background International Trade and Industry) in February 1992. The 
satellite carries an L-band Synthetic Aperture Radar 
It is well known that our forests exert strong influence on (23.5cm/1.275 GHz) with HH polarization and a look angle 
us and our environment at all levels - local, regional, of 35°. It orbits in a sun-synchronous polar orbit with a 
continental and global. The forests provide food, recurrence cycle of 44 days, acquiring data at adjacent 
pharmaceutics, timber and other important raw materials swaths on consecutive days. The standard scene size is 
to us and can keep on doing that on a long term, if only 75 by 75 km with a nominal ground resolution of 18 by 18 
managed in a sustainable way. The tropical forests are for meters for the SAR. The satellite, which also carries 
several reasons of particular interest. They are fragile optical sensors (not utilized within this project), was 
ecosystems with extensive biodiversity and they still designed specifically for land applications rather than 
cover substantial areas of the Earth. The rate at which monitoring of sea and ice, and is currently the only 
the global forests are cleared is however very high, operational L-band SAR satellite in orbit. 
although it is difficult to assess the exact extent and 
impact of this. For environmental conservation, modelling 1.3 The Global Rain Forest Mapping project 
of greenhouse gases or perhaps mapping of animal 
habitats we need to be able to accurately assess the The Global Rain Forest Mapping project (GRFM) was 
current status of the forests, but as changes occur very prompted by the recognition of the need for an up-to-date 
quickly, the need for up to date information is often data set of continental coverage over the tropical belt, 
difficult to satisfy, in particular on a regional or global together with a timely temporal operational availability of 
scale. The only viable means to accomplish this task is the JERS-1 satellite. The major aim of the GRFM project IS 
indeed by using space borne remote sensing techniques, to create a consistent data set, both in a temporal and 
in the tropical region preferably Synthetic Aperture Radar spatial sense, covering the entire equatorial belt by using 
in order to penetrate the persistent cloud cover. the L-band SAR of the JERS-1 satellite. The project also 
| aims at providing data for studies at local to global scales 
1.2 The JERS-1 satellite within the GRFM Science Projects. 
For monitoring of the tropical belt, the Japanese Earth The GRFM project is led by NASDA, but relies on 
Resources Satellite 1 (JERS-1) is perhaps the most extensive cooperation with a number of organizations 
suitable satellite for the task, given the long wave micro whose contributions will be described in detail below. 
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996