Image mosaic to strengthen global forest monitoring

November 29th, 2007 - 12:33 pm ICT by admin  

Washington, Nov 29: Scientists have completed the first of its kind image mosaic for a portion of the Amazon basin spanning almost 400,000 kilometers, in order to strengthen global forest monitoring.
This image mosaic, which is large scale and wall-to-wall, was made using synthetic aperture radar (SAR) data acquired over a six-week period by the Japanese Advanced Land Observing Satellite (ALOS) at 25 m resolution.
It is basically a composite of 116 individual scenes acquired by the Phased Array L-Band SAR (PALSAR) carried on board ALOS.
Images acquired globally over narrow timeframes provide for true “snapshots” of deforestation activities, giving leverage to monitoring programs that hinge on timely and accurate observations of forests throughout the world.
“The area that is mapped with the mosaic of images centers on the headwaters of the Xingu River, one of the Amazon’s mighty tributaries. The indigenous groups, soy farmers, smallholders, and ranchers that live in this region are top candidates to receive payments for reducing their carbon emissions,” said Daniel Nepstad , Woods Hole Research Center senior scientist. “Where this has previously taken us several months to prepare, this new mosaic took only a few days, a turnaround window that carries real significance.” he added.
“Given the regional-scale nature of climate change and environmental degradation, the importance of undertaking systematic observations cannot be overly emphasized,” said Ake Rosenqvist, who was instrumental in the design of the ALOS/PALSAR observation strategy at the Japanese Space Agency JAXA.
“With this in mind, the PALSAR observation strategy has been designed to provide consistent, wall-to-wall observations at fine resolution of all land areas on the Earth on a repetitive basis, in a manner that has earlier been conceived only for coarse and medium resolution instruments. ALOS is a pathfinder in this context and we hope that other space agencies and satellite providers will follow suit,” Rosenqvist added.
“One of the main objectives of the ALOS mission is to support global forest monitoring needs. We are excited to see that the data are now being acquired operationally, and that important scientific results can be produced,” said Masanobu Shimada , who is the ALOS Science Project Manager at JAXA.
The mosaic marks the dawn of a new era in global Earth observation because it demonstrates the unprecedented ability of the ALOS/PALSAR to deliver high-resolution (~20 meters), regional- to continental-scale image acquisitions over narrow time frames (6-8 weeks) and through dense cloud cover and precipitation.
“JAXA has launched an amazing sensor which exhibits unprecedented geometric and radiometric accuracies allowing us to generate high quality cloud free radar image mosaics with nearly no user interaction required,” said Dr. Josef Kellndorfer, who is leading the project for the Center.
“The ALOS observation plan will ensure, that these high-resolution data are acquired several times per year for years to come. With a strong sensitivity of the ALOS radar imaging sensor to vegetation structure, this marks a new era in remote sensing of natural resources,” he added. (ANI)

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