- Efforts to achieve NEC's environmental business vision
- A world first: New technology to eliminate the need for standby power in ICT equipment
- Plastic Made from Straw and Nut Shells
- Obayashi Corporation
- A bioplastic with a biomass ratio of more than 75%
- Optimizing Power and Space with ECO CENTER
- Observing Greenhouse Gases Around the Earth from Space
- Monitoring the forests from space
- High-Performance Workplaces
- e-Learning
Interview - Using Daichi's Eyes to Protect the Global Environment
Contributing to environmental protection and monitoring of CO2 emissions through forest observations
Q:
Can you give us some specific examples of how Daichi contributes to the environment?
Dr. Shimada:
I think that the simplest example is observations of tropical rain forests around the Amazon River. One of Daichi's sensors is a "PALSAR," or synthetic aperture radar, which transmits radio waves in the L-band (wavelength of about 23 cm), and creates data describing the Earth's surface based on the reflections of those radio waves. When the wavelengths are this long, the areas where trees have been cut appear smooth, so all of the radar signals are reflected, and the image comes out looking dark. Forests appear rough, however, so the radar signals are subject to back reflection, and the image comes out brighter. By comparing images across a timeline, we can determine changes resulting from logging and other cutting activities. Also, because some of the signals pass through the trees and reach the ground, we can determine the conditions close to the surface (for example, the status of flooding that is approaching the bottoms of the trees).
There are other satellites that use radio waves, but in most cases, these radio waves have short wavelengths, so the signals bounce off the tops of the trees (the "crowns"). When that happens, it is impossible to obtain accurate surface information, so it is difficult to monitor forest conditions.
Unlike light, radio waves can pass through clouds to confirm ground conditions even under cloud cover, so they are not affected by the weather. In Brazil, where the Amazon River is located, there is a rainy season that lasts from December to around February, but Daichi can monitor forest conditions even during this cloudy season. It currently provides data in response to a request for assistance from the Brazilian government. This data contributes to the monitoring of illegal logging, which has become a serious problem in that country.
Forest observation is very important, even aside from monitoring of illegal logging. The Amazon has an extremely rich supply of water, and with the repeated cycle of rainy seasons and dry seasons, the water environment changes dynamically with each passing year. By observing these two seasons and analyzing the differences along the river, it is possible to determine the area of the river where its width has expanded. Trees that were submerged during the rainy season rot and ferment, generating methane gas that adversely affects global warming even more than carbon dioxide. Therefore, by observing the number of trees during the dry season, then based on the area of the submerged land, we can estimate the volume of methane gas that will eventually be produced.
Q:
What are the expectations for Daichi in the future?
Dr. Shimada:
We expect that Daichi will come to be used for Forest observation not only around the Amazon, but in various regions throughout the world. If you take into consideration the cycle from the time the tree is cut until it is disposed of, it is estimated that cutting one ton of trees will generate about three tons of CO2 emissions. When you think of it that way, forest observations are extremely important. The Kyoto Protocol stipulates targets for reductions in CO2 emissions in various countries up to 2013, but the framework for 2013 and beyond includes allocations for logging volumes in each country. Daichi will be useful in monitoring to ensure conformance with these regulations.
Daichi will soon be used to determine the volumes of forest biomass (biological materials)*. Measurement of forest biomass volumes is also an important theme in the context of the "Kyoto & Carbon Initiative," a joint project being conducted with 21 research institutes throughout the world. By constantly monitoring changes in forest biomass volumes, it may be possible to measure changes in CO2 emission volumes as well.
We would also like to clarify the relationship between biomass volumes and the brightness of radar images. For example, a brighter image means more biomass and a darker image means less. This is a dream for researchers, but one that we would very much like to make a reality.
There are many satellites, but Daichi is the only one currently equipped with an L-band synthetic aperture radar, so it has gained considerable attention in the field of Forest observation. We hope that Daichi will be able to contribute to a wide range of research in the future.
*Biomass:
Refers to the volume of carbon contained in trees. After a tree is cut, this carbon bonds with oxygen through a variety of processes to become carbon dioxide, and this furthers the greenhouse effect in the atmosphere.
