| Publication date | May 8, 2020 |
|---|---|
| Sector | Natural ecosystems |
| Region name | Nationwide |
Climate change is expected to cause changes in vegetation, such as an increase in the deer population causing greater crop damage, more disease and insect damage, a decline in beech forests, alpine and subalpine vegetation, and the loss of cedar trees due to extreme weather.
In order to respond strategically to changes in the natural environment caused by climate change, there is an urgent need for an overview of the state of vegetation over large areas. The Ministry of the Environment Biodiversity Center of Japan conducted a extensive assessment of the natural environment using MODIS (see Note 1) data, which is updated frequently (once or twice a day) and permits observation of data nationwide (see Note 2).
The system uses composite images (see Note 3) that can eliminate cloud cover when displaying MODIS's vegetation index (VI) which are displayed in grayscale with black and white corresponding to low and high values (Fig. 1). The annual vegetation index pattern can be sorted according to vegetation categories based on training data (Fig. 2) and image classification can be used to create a map of vegetation categories. MODIS data can also be used to create a national environmental overview map (Fig. 3) of forest types (deciduous/evergreen, broad-leaved/coniferous) and other vegetation. By comparing an overview map prepared in this way with that of the previous year, it becomes possible to understand changes in land cover.
Unified analysis methods based on data from the same year nationwide can be used to quickly identify changes in vegetation and ecosystems, and can be used for prompt and appropriate conservation measures.
Fig. 1 Examples of 16-day composite images of MODIS vegetation indices in 2009 used for analysis
(Source: Satomi KAKUTA, Akihiro NAKAZAWA, Takashi SOMEYA, Yoshio TSUKAMOTO, Tomomi YANAGAWA, and Otohiko SHIMIZU: 'Understanding the general state of the Natural Environment throughout Japan with Remote Sensing Technology')
Fig. 2 Example of NDVI (Note 4) seasonal change pattern (western Japan) using training data (Source: Nature Environment Coexistence Technology Association, “Technologies and Case Studies Contributing to Climate Change Adaptation in the Natural Environment Field”)
Fig. 3 Overview map of the natural environment in Japan created using MODIS data in 2009
(Source: Satomi KAKUTA, Akihiro NAKAZAWA, Takashi SOMEYA, Yoshio TSUKAMOTO, Tomomi YANAGAWA, and Otohiko SHIMIZU: 'Understanding the general state of the Natural Environment throughout Japan with Remote Sensing Technology')
Footnote
(Note 1) Optical sensors mounted on Terra and Aqua of the Earth-Observing Satellites
(Note 2) Cf. “FY2009 Survey of the Natural Environment and Study on Efficiency of Vegetation Diagram Preparation Methods, etc.”
(Note 3) 16 daytime images are used. High and low values on the vegetation index are shown with a scale of one pixel for 250m².
(Note 4) NDVI (Normalized Difference Vegetation Index)
This index was devised for the purpose of comprehending the state of vegetation using a simple formula derived from satellite data of light reflectance from plant cover.
（Geospatial Information Authority of Japan:Geospatial Information Authority of Japan: https://www.gsi.go.jp/kankyochiri/ndvi.html）
