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Katata, Genki; Yamaguchi, Takashi*; Sato, Haruna*; Watanabe, Yoko*; Noguchi, Izumi*; Hara, Hiroshi*; Nagai, Haruyasu
Asian Journal of Atmospheric Environment, 7(1), p.17 - 24, 2013/03
Fog deposition onto the cool-temperate deciduous forest in northern Japan was estimated by the inferential method using the parameterizations of deposition velocity and liquid water content of fog (LWC). Two parameterizations of fog deposition velocity derived from the field experiments and numerical simulations were tested. The empirical function between horizontal visibility (VIS) and LWC was applied to produce hourly LWC as input data of the inferential method. Weekly mean LWC computed from VIS had a good correlation with the one sampled by an active string-fog collector. Fog deposition calculated by the inferential method agreed with that computed from thorough fall data within the factors of 2 to 3. The results indicated that the inferential method using the current parameterizations of deposition velocity and LWC can provide a rough estimation of water input due to fog deposition onto cool-temperature deciduous forests.
Yamaguchi, Takashi*; Noguchi, Izumi*; Watanabe, Yoko*; Katata, Genki; Sato, Haruna*; Hara, Hiroshi*
Asian Journal of Atmospheric Environment, 7(1), p.8 - 16, 2013/03
Fog water chemistry was measured and the fog water deposition rate was estimated by a throughfall method at Lake Mashu, northern Japan, from May to November, 2010. NH
and SO
were the most abundant cation and anion, respectively. The fog water pH ranged from 4.2 to 6.4 (mean value: 5.1). The [NH]/[SO] equivalent ratio in fog water was more than 1.0 throughout the measuring period, indicating that NH was the major factor in the neutralization of fog water. The estimated fog water deposition rate and fog water deposition were 0.11
0.22 mm h
and 117.0 mm, respectively. The estimated seasonal deposition of nitrogen in fog water, 26.1 meq m, was considerable amount compared to that of reported nitrogen deposition in rainfall.
Watanabe, Yoko*; Yamaguchi, Takashi*; Katata, Genki; Noguchi, Izumi*
Asian Journal of Atmospheric Environment, 7(1), p.1 - 7, 2013/03
SEM-EDX analysis was performed using birch leaves collected from urban area and suburb area in northern Japan. Collected leaves were divided into three treatments: (1) untreated, (2) wash leaf surface (adaxial side) with deionized water, and (3) wipe leaf surface with Kimwipes. In untreated samples, many various-shaped particles including soil particles and organic debris were deposited on the surface. Sulfur (S) particles were observed on the surface of samples collected from urban area. After treatments of (2), soil particles and S particles were washed off by water, although coarse particles still remained on the leaf surface. Although treatment of (3) removed almost all particles from surface, NaCl particles were found in both urban area and suburb area. Our study revealed that the behavior of particles depends on environmental conditions such as rain.
Rn concentration in the lower troposphere during precipitation using wet scavenging model for its decay productsTakeyasu, Masanori; Takeishi, Minoru
Asian Journal of Atmospheric Environment, 4(1), p.20 - 25, 2010/06
The atmospheric Rn concentration in rain clouds was estimated by using the wet scavenging model of its decay products with the observed data of the environmental radiation. The origin of the Rn was also discussed, when a large increase of the radiation was observed. The estimation was done for a rainfall event on Dec. 26-27, 2003, when a large increase of the radiation was observed in Tokai-mura in Ibaraki, Japan. From a backward trajectory analysis, the origin of Rn atoms for that event was back-tracked to the northeastern part of China, and it was expected that the large amount of Rn exhalated in the northeastern part of China was transported to Tokai-mura by the Eurasian continental air mass.
