Long-term observation of fog chemistry and estimation of fog water and nitrogen input via fog water deposition at a mountainous site in Hokkaido, Japan

Yamaguchi, Takashi*; Katata, Genki; Noguchi, Izumi*; Sakai, Shigekatsu*; Watanabe, Yoko*; Uematsu, Mitsuo*; Furutani, Hiroshi*

Atmospheric Research, 151, p.82 - 92, 2015/01

https://doi.org/10.1016/j.atmosres.2014.01.023

To evaluate water and nitrogen input via fog water deposition, fog chemistry and deposition around a crater lake (Mashu) in northern Japan were investigated in the growing seasons of trees in 2006-2012. The fog samples were collected using an active fog collector and droplet size distribution was measured by a droplet size spectrometer. Compared to previous iterature of exposure experiments of acid mist on plants, fog acidity in this study did not seem to injure plant leaves. The visibility (VIS)-liquid water content of fog (LWC) relationship differed between summer and autumn. Fog water deposition was calculated from LWC empirically derived from past VIS data and deposition velocity estimated using wind speed and vegetation parameters. The water and nitrogen inputs via fog water deposition accumulated for each growing season were estimated as 107-161 mm and 20-41 meq m, respectively.

Aerosol deposition and behavior on leaves in cool-temperate deciduous forests, 2; Characteristics of fog water chemistry and fog deposition in northern Japan, in 2010

Yamaguchi, Takashi*; Noguchi, Izumi*; Watanabe, Yoko*; Katata, Genki; Sato, Haruna*; Hara, Hiroshi*

Asian Journal of Atmospheric Environment, 7(1), p.8 - 16, 2013/03

https://doi.org/10.5572/ajae.2013.7.1.008

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 0.110.22 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.

Deep-sea record of impact apparently unrelated to mass extinction in the Late Triassic

Onoue, Tetsuji*; Sato, Honami*; Nakamura, Tomoki*; Noguchi, Takaaki*; Hidaka, Yoshihiro*; Shirai, Naoki*; Ebihara, Mitsuru*; Osawa, Takahito; Hatsukawa, Yuichi; Toh, Yosuke; et al.

Proceedings of the National Academy of Sciences of the United States of America, 109(47), p.19134 - 19139, 2012/11

https://doi.org/10.1073/pnas.1209486109

The 34 million year (My) interval of the Late Triassic is marked by the formation of several large impact structures on Earth. As with the Chicxulub impact event at the Cretaceous/Paleogene boudary, the Late Triassic impact events have been considered a factor in biotic extinction events in the Late Triassic (e.g., the Triassic/Jurassic boundary). However, the causal link between these impact events and a mass extinction event in the Late Triassic remains controversial because of a lack of stratigraphic records of their ejecta deposits. Here we report evidence for an impact event (platinum group elements anomaly, nickel-rich magnetite and microspherules) deposited within a Paleo-Pacific basin in the middle Norian (Upper Triassic) deep-sea sediment in Japan. This includes anomalously high abundances of iridium, up to 41.5 parts per billion (ppb), in the ejecta deposit, which suggests that the iridium anomaly may be found on a global scale. The middle Norian age of the ejecta deposit suggests that the impact event that produced the 100-km-wide Manicouagan crater in Canada8 is most likely related to its deposition. Our analysis of siliceous microfossils shows no evidence of a mass extinction event across the impact event horizon, and no contemporaneous faunal turnover is seen in other marine fossils. However, such an event has been reported among terrestrial tetrapods and floras in North America. We therefore hypothesize that the Manicouagan impact caused the catastrophic collapse of terrestrial ecosystems near the impact site, but not within the marine realm.

Iridium anomaly, Ni-rich spinels, and microspherules in upper Triassic chert of the Mino Terrane, Central Japan

Sato, Honami*; Onoue, Tetsuji*; Nakamura, Tomoki*; Noguchi, Takaaki*; Hatsukawa, Yuichi; Osawa, Takahito; Toh, Yosuke; Koizumi, Mitsuo

no journal, , 

Microspherules were discovered from a claystone layer (5 cm thick) in an Upper Triassic bedded chert succession of the Sakahogi section, Mino Terrane, Japan. An analysis of radiolarian fossils reveals that the claystone layer is correlated with the early to middle Norian stage of the Upper Triassic. The base of the layer contains 10-15% (by rock volume) green microspherules. Microspherules range in size from 200 to 300 microns. Synchrotron X-ray diffraction analysis indicates that the microspherules are composed mainly of clinoclore. Some microspherules contain a high proportion of small, euhedral to subhedral crystals of oxidized Ni-rich spinels. They are distinguished from typical igneous spinels by high contents of NiO and Fe. The geochemical signals of extraterrestrial impact are recorded in the claystone layer. Examination of the clay layer using a multiple -ray analysis system after neutron activation reveals that microspherules and Ni-rich spinels occur associated with an iridium anomaly, which levels comparable with those at the Cretaceous-Paleogene boudary. A scanning X-ray analytical microscope analysis shows high concentrations of siderophile elements such as nickel and cobalt, which would be expected from an extraterrestrial source.

Mach-Zehnder type thermo-optic switch fabricated by proton beam writing

Ozawa, Yusuke*; Kubota, Hitoshi*; Miura, Kenta*; Hanaizumi, Osamu*; Noguchi, Katsuya*; Sato, Takahiro; Ishii, Yasuyuki; Koka, Masashi; Takano, Katsuyoshi*; Okubo, Takeru; et al.

no journal, , 

Fog chemistry and droplet size distribution at Lake Mashu, northern Japan

Yamaguchi, Takashi*; Watanabe, Yoko*; Katata, Genki; Noguchi, Izumi*

no journal, , 

The fog chemistry and droplet size distributions were observed at the somma of Lake Mashu during the summertime in 2012. Daily fogwater sample were collected by using an active string fog collector. Rainwater was collected for a week using bulk samplers. Both samlples were analyzed by an ion chromatography. During the midnight, fog droplet size distribution was also observed using an optical droplet monitor from 0:00 to 4:00 in local time. The mean concentration of total nitrogen ion in fogwater (NO+NH) was 5.4 times higher than that of rainwater. Observed highly acidified fog events suggested the effects of anthropogenic air pollution and volcanoes. In October, liquid water content of large fog droplets was clearly less than other months. This may be explained by the increase of sea salt particles transported from the Japan sea.

Fabrication of Mach-Zehnder optical waveguide structures in PDMS thin films using proton beam writing

Kano, Keisuke*; Saruya, Ryota*; Kawabata, Shunsuke*; Araki, Jun*; Noguchi, Katsuya*; Kada, Wataru*; Miura, Kenta*; Kato, Hijiri*; Sato, Takahiro; Koka, Masashi; et al.

no journal, ,