{"@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/1361699994149418240.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.5194/angeo-28-1993-2010"}},{"identifier":{"@type":"URI","@value":"https://angeo.copernicus.org/articles/28/1993/2010/angeo-28-1993-2010.pdf"}}],"dc:title":[{"@value":"Fresnel scatter revisited – comparison of 50 MHz radar and radiosondes in the Arctic, the Tropics and Antarctica"}],"description":[{"type":"abstract","notation":[{"@value":"<jats:p>Abstract. High-resolution radiosondes and calibrated radars operating close to 50 MHz, are used to examine the relationship between the strength of radar scatter and refractive index gradient. Three radars are used, in Kiruna in Arctic Sweden, at Gadanki in southern India and at the Swedish/Finnish base Wasa/Aboa in Queen Maud Land, Antarctica. Calibration is accomplished using the daily variation of galactic noise measured at each site. Proportionality between radar scatter strength and the square of the mean gradient of potential refractive index, M2, is found in the upper troposphere and lower stratosphere at all three sites, confirming previously reported results from many VHF radars. If the radar scatter is interpreted as Fresnel scatter, the constant of proportionality between radar scatter and M2 is found to be the same, within the calibration uncertainties, for all three radars. The radiosondes show evidence of distinct layering with sharp gradients, extending over 10s of kilometers horizontally, but the scatter is found to be two orders of magnitude weaker than would be expected from true Fresnel scatter from such layers. Using radar reflectivities resolved to a few 100 ms, we show that this is due to strong temporal variability in the scattering conditions, possibly due to undulations of the scattering layers. The constancy of the radar scatter – M2 relationship between the different sites suggests an unexpected uniformity in these perturbations between very different regions of the globe.\n                    </jats:p>"}]}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1380567007856358146","@type":"Researcher","foaf:name":[{"@value":"S. Kirkwood"}]},{"@id":"https://cir.nii.ac.jp/crid/1381699994149418112","@type":"Researcher","foaf:name":[{"@value":"E. Belova"}]},{"@id":"https://cir.nii.ac.jp/crid/1381699994149418116","@type":"Researcher","foaf:name":[{"@value":"K. Satheesan"}]},{"@id":"https://cir.nii.ac.jp/crid/1381699994149418113","@type":"Researcher","foaf:name":[{"@value":"T. Narayana Rao"}]},{"@id":"https://cir.nii.ac.jp/crid/1381699994149418114","@type":"Researcher","foaf:name":[{"@value":"T. Rajendra Prasad"}]},{"@id":"https://cir.nii.ac.jp/crid/1381699994149418115","@type":"Researcher","foaf:name":[{"@value":"S. Satheesh Kumar"}]}],"publication":{"publicationIdentifier":[{"@type":"EISSN","@value":"14320576"}],"prism:publicationName":[{"@value":"Annales Geophysicae"}],"dc:publisher":[{"@value":"Copernicus GmbH"}],"prism:publicationDate":"2010-10-29","prism:volume":"28","prism:number":"10","prism:startingPage":"1993","prism:endingPage":"2005"},"reviewed":"false","dc:rights":["https://creativecommons.org/licenses/by/3.0/"],"url":[{"@id":"https://angeo.copernicus.org/articles/28/1993/2010/angeo-28-1993-2010.pdf"}],"createdAt":"2010-10-29","modifiedAt":"2021-01-23","relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1050282810825958912","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Comparisons between high-resolution profiles of squared refractive index gradient M[2]; measured by the Middle and Upper Atmosphere Radar and unmanned aerial vehicles (UAVs) during the Shigaraki UAV-Radar Experiment 2015 campaign"},{"@value":"Comparisons between high-resolution profiles of squared refractive index gradient &lt;i&gt;M&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt; measured by the Middle and Upper  Atmosphere Radar and unmanned aerial vehicles (UAVs) during the Shigaraki UAV-Radar Experiment 2015 campaign"}]},{"@id":"https://cir.nii.ac.jp/crid/2050307417166183168","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"The science case for the EISCAT_3D radar"}]}],"dataSourceIdentifier":[{"@type":"CROSSREF","@value":"10.5194/angeo-28-1993-2010"},{"@type":"CROSSREF","@value":"10.1186/s40645-015-0051-8_references_DOI_Ikm0c7bnt3KobUqSw3pnTz3DagS"},{"@type":"CROSSREF","@value":"10.5194/angeo-35-423-2017_references_DOI_Ikm0c7bnt3KobUqSw3pnTz3DagS"}]}