Research Highlights
Clump of rosebay: A flash report by Hokkaido Univ., Asahi Shimbun and JAXA
Monitoring of influence of 2004 Alaskan large forest fire on terrestrial environment
[September 1, 2006]
Simultaneous observation by Hokkaido Univ., Asahi Shimbun and JAXA (ref.) was completed by the end of August 2006. The Advanced Land Observing Satellite (ALOS) "Daichi" collected about 30 scenes though the weather of Alaska was not excellent. The following image is one of the valuable scenes that depict details of the ground.
A true color image of the Yukon River basin located about 200km northeast of Fairbanks, Alaska, USA, which was detected by ALOS from an altitude of 690km. The resolution of the image is 10 m. Full-scale operation of ALOS is scheduled in the autumn 2006.
The mainstream of the Yukon River looks white, which could be due to the surface wave and turbidity. Ponds and branches of the river look black. Cloud or smoke of a forest fire is shown in the right hand.
A branch of the Yukon River snakes through from lower right to upper left in the enlarged view of the area enclosed by the red square (below). The pink color spreading on either bank of the branch is caused by flowers of rosebay.
Enlarged image around a branch of the Yukon River
Rosebay field taken from the plane of Asahi Shimbun.
A flower of rosebay taken by Dr. Hayakawa, Hokkaido Univ. The size of the flower is about a half inch and the height of the stem is a few feet. Rosebay blooms in ascending order. The top flower on the stem is a sign of the end of summer.
Rosebay is a kind of fireweed, which appears primarily in the forest glade by fire or deforestation. The pink colored areas in the image approximately correspond to the damaged regions by the forest fires in 2004.
The same areas were observed by the plane of Asahi Shimbun (left). Burned trees and fallen trees were seen as well as bright rosebay. Willows and low trees were also found. The observation by the plane supported the results by ALOS that the extent of damage is closely related to the difference of vegetation.
On the ground, the group of Hokkaido University measured soil-water-content, temperature distribution, etc. The effect of forest fire on permafrost may cause the variation of plants.
Density and activity of vegetation have also been studied using the images from the Advanced Visible and Near Infrared Radiometer-2 (AVNIR-2) on the ALOS. The activity of plants in the forest glade by fire is higher than that in the other areas. The rosebay is a symptom of a forest's rebirth. Long-term observation by satellite is important to understand the recovery and growth of the forest.
