{"@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/1363670318295589248.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.1029/2003gl018704"}},{"identifier":{"@type":"URI","@value":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1029%2F2003GL018704"}},{"identifier":{"@type":"URI","@value":"https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003GL018704"}}],"dc:title":[{"@value":"On a summer maximum in the occurrence frequency of 150 km (<i>F</i><sub>1</sub>) radar echoes over Pohnpei"}],"description":[{"type":"abstract","notation":[{"@value":"<jats:p>Using three and a half years of 50 MHz radar data collected from Pohnpei, Federated States of Micronesia (6.96°N, 158.19°E geographic, 0.3° magnetic dip latitude), we show for the first time that the occurrence frequency of 150 km (or <jats:italic>F</jats:italic><jats:sub>1</jats:sub>) echoes has a broad but conspicuous maximum during northern summer in this longitude sector with minimal activity in other months. Given a seasonal similarity to sporadic <jats:italic>E</jats:italic> (<jats:italic>E</jats:italic><jats:sub><jats:italic>s</jats:italic></jats:sub>), we suggest that an <jats:italic>E</jats:italic><jats:sub><jats:italic>s</jats:italic></jats:sub>‐layer instability [<jats:ext-link xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"#grl17658-bib-0005\"><jats:italic>Cosgrove and Tsunoda</jats:italic>, 2002</jats:ext-link>] generates a polarization electric field (<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/grl17658-math-0001.gif\" xlink:title=\"equation image\"/>), which maps along geomagnetic field lines to the <jats:italic>F</jats:italic><jats:sub>1</jats:sub> region. There, <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/grl17658-math-0001.gif\" xlink:title=\"equation image\"/> forms thin plasma sheets that provide gradients to excite 3‐m‐scale plasma waves via an interchange process.</jats:p>"}]}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1383670318295589248","@type":"Researcher","foaf:name":[{"@value":"Roland T. Tsunoda"}],"jpcoar:affiliationName":[{"@value":"Center for Geospace Studies SRI International  Menlo Park California USA"}]},{"@id":"https://cir.nii.ac.jp/crid/1383670318295589249","@type":"Researcher","foaf:name":[{"@value":"Warner L. Ecklund"}],"jpcoar:affiliationName":[{"@value":"Aeronomy Laboratory, National Oceanic and Atmospheric Administration  Boulder Colorado USA"}]}],"publication":{"publicationIdentifier":[{"@type":"PISSN","@value":"00948276"},{"@type":"EISSN","@value":"19448007"}],"prism:publicationName":[{"@value":"Geophysical Research Letters"}],"dc:publisher":[{"@value":"American Geophysical Union (AGU)"}],"prism:publicationDate":"2004-03","prism:volume":"31","prism:number":"6","prism:startingPage":"810"},"reviewed":"false","dc:rights":["http://onlinelibrary.wiley.com/termsAndConditions#vor"],"url":[{"@id":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1029%2F2003GL018704"},{"@id":"https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003GL018704"}],"createdAt":"2004-03-22","modifiedAt":"2023-10-31","relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1050575495578699520","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Solar and geomagnetic activity dependence of 150-km echoes observed by the Equatorial Atmosphere Radar in Indonesia"}]},{"@id":"https://cir.nii.ac.jp/crid/1360004229807899904","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"The Solar Flux Dependence of Ionospheric 150 km Radar Echoes and Implications"}]},{"@id":"https://cir.nii.ac.jp/crid/1360004233291930496","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"On the Solstice Maxima and Azimuth‐Dependent Characteristics of the 150‐km Echoes Observed Using the Equatorial Atmosphere Radar"}]},{"@id":"https://cir.nii.ac.jp/crid/1360865815492456832","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Solved and unsolved riddles about low-latitude daytime valley region plasma waves and 150-km echoes"}]}],"dataSourceIdentifier":[{"@type":"CROSSREF","@value":"10.1029/2003gl018704"},{"@type":"CROSSREF","@value":"10.1002/2017gl074678_references_DOI_AoOfyyf5EOnVqpE1Fs4EJM0wNlq"},{"@type":"CROSSREF","@value":"10.1029/2018ja025491_references_DOI_AoOfyyf5EOnVqpE1Fs4EJM0wNlq"},{"@type":"CROSSREF","@value":"10.1186/s40623-022-01675-6_references_DOI_AoOfyyf5EOnVqpE1Fs4EJM0wNlq"},{"@type":"CROSSREF","@value":"10.3389/fspas.2023.1091319_references_DOI_FXCQs9dJDwU996ix3URoDLZn6Ur"}]}