Altitudinal characteristics of atmospheric deposition of aerosols in mountainous regions: Lessons from the Fukushima Daiichi Nuclear Power Station accident

Deposition and Dispersion of Radio‐Cesium Released Due to the Fukushima Nuclear Accident: Sensitivity to Meteorological Models and Physical Modules

“…The Iwate‐Miyagi area is isolated; thus, its contamination is presumed to have occurred due to air‐aloft processes, that is, in‐cloud scavenging. In Tochigi (Area 6) and Gumma (Area 7) prefectures, contamination occurred mainly over mountainous regions, and the importance of fog deposition (or cloud deposition) was inferred by Hososhima and Kaneyasu (), Katata et al (), Sanada et al (), and this study. The deposition of 137 Cs over both areas totaled 0.21 PBq, which represented 7.9% of the total land deposition.…”

“…Because most Japanese land is covered with mountain forests, the contribution of fog deposition was ubiquitous everywhere except in Ibaraki-Chiba, which is located in the Kanto plain and includes no mountain areas. As suggested by Hososhima and Kaneyasu (2015) and Sanada et al (2018), fog deposition was the major process in Tochigi, as well as in Gunma (30-85%). It was quite hard for the models to simulate deposition over Iwate-Miyagi, as the most dominant processes over the area were totally different between the models.…”

Atmospheric Modeling of 137Cs Plumes From the Fukushima Daiichi Nuclear Power Plant—Evaluation of the Model Intercomparison Data of the Science Council of Japan

“…Hososhima and Kaneyasu (2015) inferred from observations of altitudinal distributions of gamma dose rates in this mountainous area that the radionuclides were deposited mostly by cloud or fog deposition. Sanada et al (2018) also inferred that the deposition mechanism in this area may have been wet deposition by weak precipitation or cloud deposition, but the contributions of such mechanisms to the total deposition cannot be quantitatively determined from the currently available data. None of the models included in this study considered cloud deposition, but this mechanism should be evaluated in future studies.…”

Deposition and Dispersion of Radio‐Cesium Released due to the Fukushima Nuclear Accident: 2. Sensitivity to Aerosol Microphysical Properties of Cs‐Bearing Microparticles (CsMPs)

“…The contaminated air mass traveled over Japan and the radionuclides were deposited into and contaminated terrestrial ecosystems; this phenomenon was discovered by field measurements (Igarashi et al., 2015; Ikehara et al., 2020; NRA [Nuclear Regulation Authority], 2012; Oura et al., 2015; Sanada et al. 2014, 2018; Torii et al., 2012; Tsuruta et al., 2014, 2017, 2018, 2019) and has been investigated by numerical simulations (Kajino et al., 2018, 2019a; Morino et al, 2011, 2013; Nakajima et al., 2017; Sekiyama & Iwasaki, 2018; Sekiyama & Kajino, 2020; Saya et al., 2018; Sekiyama et al, 2015, 2017; Terada et al., 2020). The radionuclides were transported and deposited over the ocean (Aoyama et al., 2016) and further to North America (Wetherbee et al., 2012) and Europe (Masson et al., 2011, 2013).…”

“…Deposition mechanisms over land were systematically investigated by the altitudinal analysis of aircraft measurements and a numerical simulation by Sanada et al. (2018). To better simulate the atmospheric behaviors of radio‐Cs, multimodel ensemble studies have been conducted (Draxler et al., 2015, Kitayama et al., 2018; Kristiansen et al., 2016; Sato et al., 2018, 2020; SCJ [Science Council of Japan], 2014).…”