Illegal logging, afforestation projects…It is difficult to grasp changes occurring in extensive forest areas from the ground. But this becomes possible with the help of a satellite.
Do not miss out on changes in forest coverage worldwide
Illegal logging has long been a problem in the Amazon rainforest of Brazil. The Brazilian government has been using satellite images from optical sensors to detect deforestation happened in the rainforest. The system has a problem of cloud cover espacially in the rainy seasons. Illegal logging often happens in the rainy seasons since people know the drawback of the monitoring system.
To overcome the problem, PALSAR data was operationally introduced to the monitoring system since 2009. PALSAR has the outstanding features of all weather monitoring (cloud free and day and night observations) and forest cover penetration. Among various satellites which carry radar sensors, ALOS only carries L band PALSAR. The long wave lengthof PALSAR look through cloud cover and forest leaf cover, which contributed in the above mentioned deforestation monitoring.
ALOS data is adequate for the Earth environmental preservation activities support, like reforestation monitoring, regional and local land cover mapping and so on. Our data archive contains global coverage by 25 m resolution from 2007 to 2010, which enables data users to monitor changes happened in any forest. ALOS-2 also carries an upward compatible radar sensor, which promises the long time continuation of the monitoring.
Monitoring of deforestation by PALSAR
The above images show a Brasilian forest obereved by an optical sensor (left) and PALSAR overlayed as a yellow rectangle (right). Dark patterns in the PALSAR square are deforestation (either legal or illegal).
The image clearly shows deforestated areas. By making color composite of dual temporal data, changes happenend in between the obsetvation times are identified.
RESTEC had sccessfully conducted a project to detect lrregal deforestaation using PASLAR data. The project was funded by JICA in cooperation with the Brasilian Institute of Environment and Renewable Natural Resources (IBAMA) and the Science and Technology Unit of the Federal Police (DPF).
Optical sensors can also be used to observe vegetation
These images of Miyake Island were taken by an optical sensor. Even after the big eruption in 2000, small eruptions have taken place several times a year and volcanic gas emissions continue. Satellite data reveals the impact on vegetation.
Places where the vegetation has grown back healthily are shown in red; areas without regrowth are in blue. Taking these traits and comparing two images from different periods allows for the identification of places where the vegetation has returned and places where it has disappeared.
This method can be used for applications including the monitoring of afforestation.