Forests for People

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The Japan Aerospace Exploration

Agency’s forest monitoring programmes

Dr Masanobu Shimada, Earth Observation Research Center, Japan Aerospace Exploration Agency

he Japan Aerospace Exploration Agency (JAXA) has been

conducting spaceborne L-band Synthetic Aperture Radar

(SAR) programmes since the 1990s to contribute to global

Earth monitoring and more specifically, forest monitoring. The

associated satellites are the Japanese Earth Resources Satellite-1

(JERS-1), the Advanced Land Observing Satellite (ALOS) and

ALOS-2, which will be launched in 2013. These programmes aid

in the advancement of global forest monitoring as they enable

systematic observation of global land and generation of space-

time consistent high-resolution SAR images, as well as allowing

for related time-series analysis. In particular, the tools used by

JAXA to perform these tasks assist in deforestation monitoring and

forest carbon estimation. Under this framework, we produced the

world’s first global 10 metres per pixel (10-m) resolution forest/

non-forest map in October 2010. This chapter introduces JAXA’s

activities and the typical outcomes of these satellite programmes.

JERS-1 SAR: a world first

JERS-1 was launched on 11 February 1992, carrying the world’s

first operational spaceborne L-band SAR, a visible and near-

infrared sensor with stereo viewing capability and a

20-minute data recorder. It entered a 568-kilometre

sun-synchronous orbit with a revisit cycle time of 44

days. Following its launch, JERS-1 operated for six

and a half years (1992-1998), which corresponded

to the mission request from users both inside and

outside JAXA as well as several foreign ground

stations. During this period it collected 400,000 SAR

images globally.

In 1995, two events initiated forest monitoring

using the JERS-1 SAR. During the initial mission

check of the SAR, global images were collected.

Several images from the Amazon were severely

contaminated with dark stripes, which were not

artificial patterns but were strongly related to the

land features of smooth surfaces, which showed a

strong correlation to deforestation in Rondonia. The

second initiating event was the JERS-1 verification

programme, which included an announcement of

opportunity to investigate the potential of JERS-1.

NASDA/JPL/JRC Forest Mapping Projects

Forest monitoring areas: by Global Rain Forest Mapping Project (GRMP) (red) and by Global Boreal Forest Mapping Project (GBFM) (blue)