{"@context":{"@vocab":"https://cir.nii.ac.jp/schema/1.0/","rdfs":"http://www.w3.org/2000/01/rdf-schema#","dc":"http://purl.org/dc/elements/1.1/","dcterms":"http://purl.org/dc/terms/","foaf":"http://xmlns.com/foaf/0.1/","prism":"http://prismstandard.org/namespaces/basic/2.0/","cinii":"http://ci.nii.ac.jp/ns/1.0/","datacite":"https://schema.datacite.org/meta/kernel-4/","ndl":"http://ndl.go.jp/dcndl/terms/","jpcoar":"https://github.com/JPCOAR/schema/blob/master/2.0/"},"@id":"https://cir.nii.ac.jp/crid/1363664919709784704.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.5194/amt-12-5363-2019"}},{"identifier":{"@type":"URI","@value":"https://amt.copernicus.org/articles/12/5363/2019/amt-12-5363-2019.pdf"}}],"resourceType":"学術雑誌論文(journal article)","dc:title":[{"@value":"Free-fall experiments of volcanic ash particles using a 2-D  video disdrometer"}],"description":[{"type":"abstract","notation":[{"@value":"<jats:p>Abstract. Information of aerodynamic parameters of volcanic ash particles, such as\nterminal velocity, axis ratio, and canting angle, are necessary for\nquantitative ash-fall estimations with weather radar. In this study,\nfree-fall experiments of volcanic ash particles were accomplished using a\ntwo-dimensional video disdrometer under controlled conditions. Samples containing a rotating symmetric axis were selected and divided into\nfive types according to shape and orientation: oblate spheroid with\nhorizontal rotating axis (OH), oblate spheroid with vertical axis (OV),\nprolate spheroid with horizontal rotating axis (PH), prolate spheroid with\nvertical rotating axis (PV), and sphere (Sp). The horizontally (OH and PH)\nand vertically (OV and PV) oriented particles were present in proportions of\n76 % and 22 %, and oblate and prolate spheroids were in proportions of\n76 % and 24 %, respectively. The most common shape type was OH (57 %). The terminal velocities of OH, OV, PH, PV, and Sp were obtained analyzing\n2-D video disdrometer data. The terminal velocities of PV were highest compared to those of\nother particle types. The lowest terminal velocities were found in OH\nparticles. It is interesting that the terminal velocities for OH decreased\nrapidly in the range 0.5<D<1 mm, corresponding to the\ndecrease in axis ratio (i.e., smaller the particle, the flatter the shape).\nThe axis ratios of all particle types except Sp were found to be converged\nto 0.94 at D>2 mm. The histogram of canting angles followed unimodal and bimodal distributions\nwith respect to horizontally and vertically oriented particles,\nrespectively. The mean values and the standard deviation of entire particle\nshape types were close to 0 and 10∘, respectively,\nunder calm atmospheric conditions.</jats:p>"}]}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1383664919709784576","@type":"Researcher","foaf:name":[{"@value":"Sung-Ho Suh"}]},{"@id":"https://cir.nii.ac.jp/crid/1420001326217122048","@type":"Researcher","personIdentifier":[{"@type":"KAKEN_RESEARCHERS","@value":"10360364"},{"@type":"NRID","@value":"1000010360364"},{"@type":"NRID","@value":"9000363502231"},{"@type":"NRID","@value":"9000409170311"},{"@type":"NRID","@value":"9000406062238"},{"@type":"NRID","@value":"9000402796876"},{"@type":"RESEARCHMAP","@value":"https://researchmap.jp/maki3"}],"foaf:name":[{"@value":"Masayuki Maki"}]},{"@id":"https://cir.nii.ac.jp/crid/1383664919709784833","@type":"Researcher","foaf:name":[{"@value":"Masato Iguchi"}]},{"@id":"https://cir.nii.ac.jp/crid/1383664919709784834","@type":"Researcher","foaf:name":[{"@value":"Dong-In Lee"}]},{"@id":"https://cir.nii.ac.jp/crid/1383664919709784705","@type":"Researcher","foaf:name":[{"@value":"Akihiko Yamaji"}]},{"@id":"https://cir.nii.ac.jp/crid/1383664919709784704","@type":"Researcher","foaf:name":[{"@value":"Tatsuya Momotani"}]}],"publication":{"publicationIdentifier":[{"@type":"EISSN","@value":"18678548"}],"prism:publicationName":[{"@value":"Atmospheric Measurement Techniques"}],"dc:publisher":[{"@value":"Copernicus GmbH"}],"prism:publicationDate":"2019-10-09","prism:volume":"12","prism:number":"10","prism:startingPage":"5363","prism:endingPage":"5379"},"reviewed":"false","dcterms:accessRights":"http://purl.org/coar/access_right/c_abf2","dc:rights":["https://creativecommons.org/licenses/by/4.0/"],"url":[{"@id":"https://amt.copernicus.org/articles/12/5363/2019/amt-12-5363-2019.pdf"}],"createdAt":"2019-10-09","modifiedAt":"2025-02-01","foaf:topic":[{"@id":"https://cir.nii.ac.jp/all?q=Earthwork.%20Foundations","dc:title":"Earthwork. Foundations"},{"@id":"https://cir.nii.ac.jp/all?q=TA715-787","dc:title":"TA715-787"},{"@id":"https://cir.nii.ac.jp/all?q=Environmental%20engineering","dc:title":"Environmental engineering"},{"@id":"https://cir.nii.ac.jp/all?q=TA170-171","dc:title":"TA170-171"}],"project":[{"@id":"https://cir.nii.ac.jp/crid/1040000781897326720","@type":"Project","projectIdentifier":[{"@type":"KAKEN","@value":"16H03145"},{"@type":"JGN","@value":"JP16H03145"},{"@type":"URI","@value":"https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16H03145/"}],"notation":[{"@language":"ja","@value":"降水時の爆発的火山噴火に関するレーダ気象学的研究"},{"@language":"en","@value":"Radar meteorological studies on explosive volcanic eruptions under precipitation conditioner precipitation"}]}],"relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1050001335841024896","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Rapid dike intrusion into Sakurajima volcano on August 15, 2015, as detected by multi-parameter ground deformation observations"}]},{"@id":"https://cir.nii.ac.jp/crid/1050564285805230720","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Orographic effects on the transport and deposition of volcanic ash: A case study of Mt. 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