Temporal Change of Space-Borne Vegetation Index at Area Nearby the Fukushima Daiichi Nuclear Power Plant

Using multi-temporal KOMPSAT-3/3A high-resolution satellite images, the Normalized Difference Vegetation Index (NDVI) for the area around the Fukushima daiichi nuclear power plant was determined, and the pattern of vegetation changes was investigated. As well, Landsat-8 and Sentinel-2 images were used. The NDVI products obtained from these three sensors were validated and compared with land cover and land use map of the same area for visual interpretation. The main results of this study showed that the NDVI in the mid-2010 was low within area-of-the interests in the vicinity of the nuclear power plant, but the vegetated area continued to expand until 2021. It can be interpreted as a result of a decrease in human activities. In particular, the map of differences between the mid-2010 and 2021 of high-resolution images revealed detailed spatial features rather than those of the mid-resolution images. In disaster areas where access is restricted, such as the areas around the Fukushima nuclear power plant, and where it is difficult to collect field data, obtaining classification products with high accuracy using satellite images is challenging. It helps to analyze them using primary products such as vegetation indices exactly determined from the high-resolution satellite imagery.

1. Introduction

After the Great East Japan Earthquake on March 11, 2011, the environmental impact on the surrounding area of radioactive materials from the Fukushima Daiichi(1st) nuclear power plant has become a serious problem [1]. High-resolution satellite images are needed more because it is difficult to collect field data in contaminated areas due to radiation leakage, but there are few studies on these areas, and most studies published so far have used mid- to low-resolution satellite images such as Landsat and MODIS. This study attempted to confirm changes in vegetation due to radioactive substances through time series analysis of the Normalized Difference Vegetation Index (NDVI) around the Fukushima 1st Nuclear Power Plant using KOMPSAT-3/3A satellite images.