{"@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/1360004232184412544.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.1016/j.icarus.2016.06.011"}},{"identifier":{"@type":"URI","@value":"https://api.elsevier.com/content/article/PII:S001910351630286X?httpAccept=text/xml"}},{"identifier":{"@type":"URI","@value":"https://api.elsevier.com/content/article/PII:S001910351630286X?httpAccept=text/plain"}}],"resourceType":"学術雑誌論文(journal article)","dc:title":[{"@value":"Ground-based observation of the cyclic nature and temporal variability of planetary-scale UV features at the Venus cloud top level"}],"description":[{"notation":[{"@value":"Abstract   A planetary-scale bright and dark UV feature, known as the “Y-feature,” rotates around Venus with a period of 4–5 days and has been long-time interpreted as planetary waves. When assuming this, its rotation period and spatial structure might help to understand the propagation of the planetary-scale waves and find out their role in the acceleration-deceleration of the zonal wind speed, which is essential for understanding the super-rotation of the planet. The rotation period of the UV feature varied over the course of observation by the Pioneer Venus orbiter. However, in previous explorations of Venus such as Pioneer Venus and Venus Express, the spacecraft were operated in nearly fixed inertial space. As a result, the periodicity variations on sub-yearly timescales (one Venusian year is ∼224 Earth days) were obscured by the limitations of continuous dayside observations. We newly conducted six periods of ground-based Venus imaging observations at 365 nm from mid-August 2013 to the end of June 2014. Each observation period spanned over half or one month, enabling long-term monitoring of Venus’ atmosphere above the equator region. Distributions of the relative brightness were obtained from the equatorial (EQ) to mid-latitudinal regions in both hemispheres, and from the cyclical variations of these distributions we deduced the rotation periods of the UV features of the cloud tops brightness. The relative brightness exhibited periods of 5.2 and 3.5 days above 90% of significance. The relative intensities of these two significant components also seemed subject to temporal variations. Although the 3.5-day component considered persists throughout the observation periods, its dominance over the longer period varied in a cyclic fashion. The prevailing first significant mode seems to change from 5.2-day waves to 3.5-day waves in about nine months, which is clearly inconsistent with the Venusian year. Clear periodic perturbations, indicating stability of the planetary-scale UV-feature, were observed only in the presence of single longer or shorter periodic waves. During the transition periods of dominant-wave changing, the amplitude of the relative brightness was largely changed. This can be explained by the deformation of the Y-shaped UV feature as observed by Pioneer Venus in 1979."}]}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1380004232184412546","@type":"Researcher","foaf:name":[{"@value":"Masataka Imai"}]},{"@id":"https://cir.nii.ac.jp/crid/1380004232184412545","@type":"Researcher","foaf:name":[{"@value":"Yukihiro Takahashi"}]},{"@id":"https://cir.nii.ac.jp/crid/1380004232184412550","@type":"Researcher","foaf:name":[{"@value":"Makoto Watanabe"}]},{"@id":"https://cir.nii.ac.jp/crid/1420001326220837376","@type":"Researcher","personIdentifier":[{"@type":"KAKEN_RESEARCHERS","@value":"40645876"},{"@type":"NRID","@value":"1000040645876"},{"@type":"NRID","@value":"9000017113859"},{"@type":"NRID","@value":"9000375922330"},{"@type":"NRID","@value":"9000409975511"},{"@type":"NRID","@value":"9000404336087"},{"@type":"NRID","@value":"9000380975147"},{"@type":"NRID","@value":"9000332697338"},{"@type":"NRID","@value":"9000408855139"},{"@type":"NRID","@value":"9000345347157"},{"@type":"NRID","@value":"9000410886404"},{"@type":"NRID","@value":"9000019055107"},{"@type":"NRID","@value":"9000399009906"},{"@type":"NRID","@value":"9000386169055"},{"@type":"NRID","@value":"9000332699977"},{"@type":"NRID","@value":"9000327110440"},{"@type":"NRID","@value":"9000409029538"},{"@type":"NRID","@value":"9000399009900"},{"@type":"NRID","@value":"9000409497253"},{"@type":"NRID","@value":"9000340446009"},{"@type":"NRID","@value":"9000363172447"},{"@type":"NRID","@value":"9000365042496"},{"@type":"NRID","@value":"9000309174000"},{"@type":"NRID","@value":"9000271159502"},{"@type":"NRID","@value":"9000369353664"},{"@type":"NRID","@value":"9000399010009"},{"@type":"NRID","@value":"9000412653050"},{"@type":"NRID","@value":"9000405126045"},{"@type":"NRID","@value":"9000399009821"},{"@type":"NRID","@value":"9000409848502"},{"@type":"NRID","@value":"9000345199795"},{"@type":"NRID","@value":"9000399352154"},{"@type":"NRID","@value":"9000257894149"},{"@type":"NRID","@value":"9000408855706"},{"@type":"RESEARCHMAP","@value":"https://researchmap.jp/trk"}],"foaf:name":[{"@value":"Toru Kouyama"}]},{"@id":"https://cir.nii.ac.jp/crid/1380004232184412544","@type":"Researcher","foaf:name":[{"@value":"Shigeto Watanabe"}]},{"@id":"https://cir.nii.ac.jp/crid/1380004232184412549","@type":"Researcher","foaf:name":[{"@value":"Shuhei Gouda"}]},{"@id":"https://cir.nii.ac.jp/crid/1380004232184412548","@type":"Researcher","foaf:name":[{"@value":"Yuya Gouda"}]}],"publication":{"publicationIdentifier":[{"@type":"PISSN","@value":"00191035"}],"prism:publicationName":[{"@value":"Icarus"}],"dc:publisher":[{"@value":"Elsevier BV"}],"prism:publicationDate":"2016-11","prism:volume":"278","prism:startingPage":"204","prism:endingPage":"214"},"reviewed":"false","dc:rights":["https://www.elsevier.com/tdm/userlicense/1.0/"],"url":[{"@id":"https://api.elsevier.com/content/article/PII:S001910351630286X?httpAccept=text/xml"},{"@id":"https://api.elsevier.com/content/article/PII:S001910351630286X?httpAccept=text/plain"}],"createdAt":"2016-06-25","modifiedAt":"2022-06-18","project":[{"@id":"https://cir.nii.ac.jp/crid/1040000781862675072","@type":"Project","projectIdentifier":[{"@type":"KAKEN","@value":"15K17767"},{"@type":"JGN","@value":"JP15K17767"},{"@type":"URI","@value":"https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15K17767/"}],"notation":[{"@language":"ja","@value":"金星成層圏での風速変動メカニズムの解明"},{"@language":"en","@value":"Mechanism of zonal wind variation in Venus stratosphere"}]},{"@id":"https://cir.nii.ac.jp/crid/1040000781895916544","@type":"Project","projectIdentifier":[{"@type":"KAKEN","@value":"16H02225"},{"@type":"JGN","@value":"JP16H02225"},{"@type":"URI","@value":"https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16H02225/"}],"notation":[{"@language":"ja","@value":"あかつき・地上観測と数値モデリングの連携による金星大気力学の研究"},{"@language":"en","@value":"Observational and numerical study on the Venus atmospheric dynamics"}]},{"@id":"https://cir.nii.ac.jp/crid/1040282256821660800","@type":"Project","projectIdentifier":[{"@type":"KAKEN","@value":"15K05303"},{"@type":"JGN","@value":"JP15K05303"},{"@type":"URI","@value":"https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15K05303/"}],"notation":[{"@language":"ja","@value":"大気プラズマ結合過程の研究 ー日米共同実験ー"},{"@language":"en","@value":"Coupling between neutral atmosphere and plasma"}]}],"relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1360005518173730176","@type":"Article","resourceType":"学術雑誌論文(journal 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