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4 results on '"Momoka Yoshizue"'

1. Measurements of Aerosol Particle Size Distributions and INPs Over the Southern Ocean in the Late Austral Summer of 2017 on Board the R/V Mirai: Importance of the Marine Boundary Layer Structure

Author

Takuma Miyakawa, Fumikazu Taketani, Yutaka Tobo, Kazuhiko Matsumoto, Momoka Yoshizue, Masayuki Takigawa, and Yugo Kanaya

Subjects
SSA, MBL, Southern Ocean, INPs, wave breaking, Astronomy, QB1-991, Geology, QE1-996.5
Abstract

Abstract The Southern Ocean (SO) is a unique region with rich ecosystems and minimal anthropogenic and terrestrial natural impacts especially during austral summer. We conducted measurements and sampling of aerosol particles to investigate the characteristics and role of aerosol particles in cloud formation on Japanese research vessel Mirai over the SO in the late austral summer of 2017. Observations of air masses with minimal terrestrial impacts indicated that bimodal aerosol particle size distributions were mostly observed over the SO and relative abundances of two modes varied with the changes in the structure of the marine boundary layer (MBL) such as surface mixing layer. As the local minimum diameter between two modes (DH) is considered a critical size for cloud‐droplet activation in the MBL, we analyzed the aerosol particles with diameter larger than DH (CNAcc) as a proxy for cloud condensation nuclei. Variations in the concentrations of aerosol particles with diameter larger than 300 nm were accounted for by the sea‐spray source function, whereas it substantially underestimated those of CNAcc. This implies the significance of the nonsea‐spray sources of CNAcc in the MBL over the SO. The concentrations of ice nucleating particles (NINPs) active at −25°C were 20–100 m−3, consistent with recent observations over the summertime SO. The observational evidence of very low NINPs relative to the CNAcc concentrations (40–110 cm−3) over a wide area of the SO is important for predicting the effects of cloud radiative properties on the radiative balances over the SO using climate models.

Published
2023
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2. Detection of Aerosol Particles from Siberian Biomass Burning over the Western North Pacific

Author

Momoka Yoshizue, Fumikazu Taketani, Kouji Adachi, Yoko Iwamoto, Yasunori Tohjima, Tatsuhiro Mori, and Kazuhiko Miura

Subjects
tarball, Pacific Ocean, individual particle analysis, Meteorology. Climatology, QC851-999
Abstract

Carbonaceous aerosol particles emitted from biomass burning (BB) have a large impact on the global climate. In particular, tarball particles (TBs), which are spherical organic aerosol particles, account for a large proportion of aerosol particles from BB. In this study, we collected aerosol particles over the western North Pacific and analyzed them using transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM-EDX) to reveal their shape and composition. We detected TBs and organic carbon particles originating from Siberian forest fires. To the best of our knowledge, this is the first case in which a large number of TBs have been found over the Pacific Ocean far from the BB source. The spherical shapes of the TBs were maintained even after long-range transport. In addition, our individual analysis of TBs showed that the size and composition of TBs differ depending on the air mass origin. The occurrence and microphysical properties of TBs are important to accurately evaluate the impact of TBs on climate. Our results imply that TBs can be transported to the Arctic and have an influence on radiative forcing over the ocean and in the Arctic.

Published
2020
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3. Individual particle analysis of marine aerosols collected during the North–South transect cruise in the Pacific Ocean and its marginal seas

Author

Momoka Yoshizue, Yoko Iwamoto, Kouji Adachi, Mitsuo Uematsu, Kazuhiko Miura, Siyi Sun, and Shungo Kato

Subjects
food.ingredient, 010504 meteorology & atmospheric sciences, 010505 oceanography, Sea salt, Oceanography, 01 natural sciences, Aerosol, chemistry.chemical_compound, Deposition (aerosol physics), food, chemistry, Environmental chemistry, Environmental science, Particle, Cloud condensation nuclei, Dimethyl sulfide, Sulfate, Scavenging, 0105 earth and related environmental sciences
Abstract

Sea-salt particles are major aerosol constituents in the marine boundary layer (MBL) and are chemically modified by acidic substances from anthropogenic, volcanic, and biogenic sources. When these acidic substances react with sea-salt particles, they can be easily scavenged from the MBL. This scavenging process influences the concentration of cloud condensation nuclei in the MBL. In this study, differences in chemical compositions of sea-salt particles collected over the Pacific Ocean and its marginal seas were investigated based on an individual particle analysis. The sources of the acidic substances that modified sea-salt particles were also estimated. Approximately 70% of the analyzed particles were fresh sea-salt particles. However, a sample collected near Guam was dominated by sulfates and was affected by polluted air masses that originated over the Asian continent. The aerosols collected around the Aleutian Islands included a large number of sulfates and modified sea-salt particles. Individual particle composition analyses indicate that these sea-salt particles were modified by methanesulfonic acid produced from marine biota and sulfuric acid from volcanic gas from the Kamchatka Peninsula. The gravitational deposition velocities of sulfates and modified sea-salt particles were calculated based on measured particle sizes. The results suggested that if acidic substances react with sea-salt particles, their lifetime in the atmosphere could be shortened due to dry deposition. Therefore, it is necessary to consider the scavenging effect of sea-salt particles for estimating the climate cooling effect by clouds over the ocean.

Published
2019
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4. Detection of Aerosol Particles from Siberian Biomass Burning over the Western North Pacific

Author

Yasunori Tohjima, Tatsuhiro Mori, Momoka Yoshizue, Yoko Iwamoto, Kouji Adachi, Kazuhiko Miura, and Fumikazu Taketani

Subjects
Total organic carbon, Atmospheric Science, Pacific Ocean, 010504 meteorology & atmospheric sciences, tarball, lcsh:QC851-999, 010501 environmental sciences, Environmental Science (miscellaneous), Radiative forcing, Atmospheric sciences, 01 natural sciences, Pacific ocean, The arctic, Aerosol, Individual analysis, Environmental science, lcsh:Meteorology. Climatology, Biomass burning, Air mass, 0105 earth and related environmental sciences, individual particle analysis
Abstract

Carbonaceous aerosol particles emitted from biomass burning (BB) have a large impact on the global climate. In particular, tarball particles (TBs), which are spherical organic aerosol particles, account for a large proportion of aerosol particles from BB. In this study, we collected aerosol particles over the western North Pacific and analyzed them using transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM-EDX) to reveal their shape and composition. We detected TBs and organic carbon particles originating from Siberian forest fires. To the best of our knowledge, this is the first case in which a large number of TBs have been found over the Pacific Ocean far from the BB source. The spherical shapes of the TBs were maintained even after long-range transport. In addition, our individual analysis of TBs showed that the size and composition of TBs differ depending on the air mass origin. The occurrence and microphysical properties of TBs are important to accurately evaluate the impact of TBs on climate. Our results imply that TBs can be transported to the Arctic and have an influence on radiative forcing over the ocean and in the Arctic.

Published
2020
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