Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars

Descripción del Articulo

Resumen.
Detalles Bibliográficos
Autores: Chau Chong Shing, Jorge Luis, Woodman Pollitt, Ronald Francisco
Formato: otro
Fecha de Publicación:2005
Institución:Instituto Geofísico del Perú
Repositorio:IGP-Institucional
Lenguaje:inglés
OAI Identifier:oai:repositorio.igp.gob.pe:20.500.12816/556
Enlace del recurso:http://hdl.handle.net/20.500.12816/556
Nivel de acceso:acceso abierto
Materia:Echoes
Rockets(Aeronautics)
Radar
Equatorial electrojet
http://purl.org/pe-repo/ocde/ford#1.05.01
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dc.title.none.fl_str_mv Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars
title Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars
spellingShingle Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars
Chau Chong Shing, Jorge Luis
Echoes
Rockets(Aeronautics)
Radar
Equatorial electrojet
http://purl.org/pe-repo/ocde/ford#1.05.01
title_short Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars
title_full Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars
title_fullStr Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars
title_full_unstemmed Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars
title_sort Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radars
author Chau Chong Shing, Jorge Luis
author_facet Chau Chong Shing, Jorge Luis
Woodman Pollitt, Ronald Francisco
author_role author
author2 Woodman Pollitt, Ronald Francisco
author2_role author
dc.contributor.author.fl_str_mv Chau Chong Shing, Jorge Luis
Woodman Pollitt, Ronald Francisco
dc.subject.none.fl_str_mv Echoes
Rockets(Aeronautics)
Radar
Equatorial electrojet
topic Echoes
Rockets(Aeronautics)
Radar
Equatorial electrojet
http://purl.org/pe-repo/ocde/ford#1.05.01
dc.subject.ocde.none.fl_str_mv http://purl.org/pe-repo/ocde/ford#1.05.01
description Resumen.
publishDate 2005
dc.date.accessioned.none.fl_str_mv 2017-12-21T19:41:45Z
dc.date.available.none.fl_str_mv 2017-12-21T19:41:45Z
dc.date.issued.fl_str_mv 2005
dc.type.none.fl_str_mv info:eu-repo/semantics/other
format other
dc.identifier.uri.none.fl_str_mv http://hdl.handle.net/20.500.12816/556
url http://hdl.handle.net/20.500.12816/556
dc.language.iso.none.fl_str_mv eng
language eng
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Instituto Geofísico del Perú, Radio Observatorio de Jicamarca
publisher.none.fl_str_mv Instituto Geofísico del Perú, Radio Observatorio de Jicamarca
dc.source.none.fl_str_mv reponame:IGP-Institucional
instname:Instituto Geofísico del Perú
instacron:IGP
instname_str Instituto Geofísico del Perú
instacron_str IGP
institution IGP
reponame_str IGP-Institucional
collection IGP-Institucional
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spelling Chau Chong Shing, Jorge LuisWoodman Pollitt, Ronald Francisco2017-12-21T19:41:45Z2017-12-21T19:41:45Z2005http://hdl.handle.net/20.500.12816/556Resumen.Equatorial electrojet (EEJ) field-aligned irregularities have been studied intensively using radars and in-situ rocket-bome sensors since early 1960s. Their main characteristics are well known. For example, two types of echoes are usually observed: (1) those caused by gradient drift instabilities (type 2), and (2) Farley-Buneman instabilities (type 1 ). Type 2 echoes are characterized by wide spectral width and mean Doppler proportional to the electron drift velocity. Type 1 echoes are characterized by narrow spectra and its Doppler is believed to represent the ion-acoustic speed. In this presentation we will present examples of spectral characteristics observed during unusual magnetic conditions. For example during counter EEJ (CEEJ) conditions we have observed spectral characteristics of (1) type 2 echoes, (2) type 1 echoes, and (3) pure two stream echoes. In addition, during the large 2003 Halloween storm, a concurrent three-type spectra echo was observed, characterized by two "ion acoustic" speeds of -150-200 mis difference in less than 5 km altitudinal difference. We think the latter spectra is a combination of normal EEJ echoes, i.e., type 1 and type 2 echoes, both occurring in the unstable part of the density gradient at the lower heights; and pure two stream echoes occurring in the stable part of the density gradient at the upper heights. However, as mentioned before, these results are puzzling since velocity differences of -l 00-150 mis in less than 5 km are not expected. Explaining the observations as an increase in the nominal ion-acoustic speed through much higher temperatures than expected violates everything we know about the neutral atrnospheric temperature near the mesopause. Another possible source would be zonal wind differences, but their effects are expected to account for less than 50 mis differences. Finally, we will show the day-to-day variability of type-I speeds. During strong electrojet conditions, these speeds are much larger than the expected ion-acoustic speeds. Recently, St. -Maurice et al. [2004] has included electron thermal fluctuations (which are caused by electron adiabatic heating) to derived instability threshold speeds that match the upper limit reached by observations at Pohnpei and other equatorial radars. Briefly, the inclusion of these thermal fluctuations could explain the observed large type 1 speeds, since the derived threshold speed increases rapidly with decreasing altitude reaching a value of -1.5 times as large as the isothermal ion acoustic speed. It is important to note that this generalized theory does not explain the observations described in the previous paragraph, i.e., larger type- l speeds (100-150 mis) in less than 5 km, being larger at higher altitude.ROJ.application/pdfengInstituto Geofísico del Perú, Radio Observatorio de Jicamarcainfo:eu-repo/semantics/openAccessEchoesRockets(Aeronautics)RadarEquatorial electrojethttp://purl.org/pe-repo/ocde/ford#1.05.01Unusual spectral and temporal characteristics of equatorial electrojet irregularities observed with the Jicamarca VHF radarsinfo:eu-repo/semantics/otherreponame:IGP-Institucionalinstname:Instituto Geofísico del Perúinstacron:IGPORIGINALUnusual spectral and temporal characteristics of equatorial electrojet irregularities observed wi.PDFapplication/pdf10754https://repositorio.igp.gob.pe/bitstreams/0189feaa-8bf1-45b2-801b-54ae3d4229af/download95d048596976c02518694d47227395b5MD51LICENSElicense.txttext/plain1748https://repositorio.igp.gob.pe/bitstreams/319979b0-c514-4e26-b022-490a16290efa/download8a4605be74aa9ea9d79846c1fba20a33MD52THUMBNAILUnusual spectral and temporal characteristics of equatorial electrojet irregularities observed wi.PDF.jpgUnusual spectral and temporal characteristics of equatorial electrojet irregularities observed wi.PDF.jpgIM Thumbnailimage/jpeg132655https://repositorio.igp.gob.pe/bitstreams/3c1194eb-6b6e-40e2-8d54-5efc18de4eb4/download1cdf282a236d680df51e05a3d4c24eb1MD53TEXTUnusual spectral and temporal characteristics of equatorial electrojet irregularities observed wi.PDF.txtUnusual spectral and temporal characteristics of equatorial electrojet irregularities observed wi.PDF.txtExtracted texttext/plain1https://repositorio.igp.gob.pe/bitstreams/309126a6-50f9-4483-b692-168982b99d07/download68b329da9893e34099c7d8ad5cb9c940MD5420.500.12816/556oai:repositorio.igp.gob.pe:20.500.12816/5562024-10-12 22:18:50.95open.accesshttps://repositorio.igp.gob.peRepositorio Geofísico Nacionalbiblio@igp.gob.peTk9URTogUExBQ0UgWU9VUiBPV04gTElDRU5TRSBIRVJFClRoaXMgc2FtcGxlIGxpY2Vuc2UgaXMgcHJvdmlkZWQgZm9yIGluZm9ybWF0aW9uYWwgcHVycG9zZXMgb25seS4KCk5PTi1FWENMVVNJVkUgRElTVFJJQlVUSU9OIExJQ0VOU0UKCkJ5IHNpZ25pbmcgYW5kIHN1Ym1pdHRpbmcgdGhpcyBsaWNlbnNlLCB5b3UgKHRoZSBhdXRob3Iocykgb3IgY29weXJpZ2h0Cm93bmVyKSBncmFudHMgdG8gRFNwYWNlIFVuaXZlcnNpdHkgKERTVSkgdGhlIG5vbi1leGNsdXNpdmUgcmlnaHQgdG8gcmVwcm9kdWNlLAp0cmFuc2xhdGUgKGFzIGRlZmluZWQgYmVsb3cpLCBhbmQvb3IgZGlzdHJpYnV0ZSB5b3VyIHN1Ym1pc3Npb24gKGluY2x1ZGluZwp0aGUgYWJzdHJhY3QpIHdvcmxkd2lkZSBpbiBwcmludCBhbmQgZWxlY3Ryb25pYyBmb3JtYXQgYW5kIGluIGFueSBtZWRpdW0sCmluY2x1ZGluZyBidXQgbm90IGxpbWl0ZWQgdG8gYXVkaW8gb3IgdmlkZW8uCgpZb3UgYWdyZWUgdGhhdCBEU1UgbWF5LCB3aXRob3V0IGNoYW5naW5nIHRoZSBjb250ZW50LCB0cmFuc2xhdGUgdGhlCnN1Ym1pc3Npb24gdG8gYW55IG1lZGl1bSBvciBmb3JtYXQgZm9yIHRoZSBwdXJwb3NlIG9mIHByZXNlcnZhdGlvbi4KCllvdSBhbHNvIGFncmVlIHRoYXQgRFNVIG1heSBrZWVwIG1vcmUgdGhhbiBvbmUgY29weSBvZiB0aGlzIHN1Ym1pc3Npb24gZm9yCnB1cnBvc2VzIG9mIHNlY3VyaXR5LCBiYWNrLXVwIGFuZCBwcmVzZXJ2YXRpb24uCgpZb3UgcmVwcmVzZW50IHRoYXQgdGhlIHN1Ym1pc3Npb24gaXMgeW91ciBvcmlnaW5hbCB3b3JrLCBhbmQgdGhhdCB5b3UgaGF2ZQp0aGUgcmlnaHQgdG8gZ3JhbnQgdGhlIHJpZ2h0cyBjb250YWluZWQgaW4gdGhpcyBsaWNlbnNlLiBZb3UgYWxzbyByZXByZXNlbnQKdGhhdCB5b3VyIHN1Ym1pc3Npb24gZG9lcyBub3QsIHRvIHRoZSBiZXN0IG9mIHlvdXIga25vd2xlZGdlLCBpbmZyaW5nZSB1cG9uCmFueW9uZSdzIGNvcHlyaWdodC4KCklmIHRoZSBzdWJtaXNzaW9uIGNvbnRhaW5zIG1hdGVyaWFsIGZvciB3aGljaCB5b3UgZG8gbm90IGhvbGQgY29weXJpZ2h0LAp5b3UgcmVwcmVzZW50IHRoYXQgeW91IGhhdmUgb2J0YWluZWQgdGhlIHVucmVzdHJpY3RlZCBwZXJtaXNzaW9uIG9mIHRoZQpjb3B5cmlnaHQgb3duZXIgdG8gZ3JhbnQgRFNVIHRoZSByaWdodHMgcmVxdWlyZWQgYnkgdGhpcyBsaWNlbnNlLCBhbmQgdGhhdApzdWNoIHRoaXJkLXBhcnR5IG93bmVkIG1hdGVyaWFsIGlzIGNsZWFybHkgaWRlbnRpZmllZCBhbmQgYWNrbm93bGVkZ2VkCndpdGhpbiB0aGUgdGV4dCBvciBjb250ZW50IG9mIHRoZSBzdWJtaXNzaW9uLgoKSUYgVEhFIFNVQk1JU1NJT04gSVMgQkFTRUQgVVBPTiBXT1JLIFRIQVQgSEFTIEJFRU4gU1BPTlNPUkVEIE9SIFNVUFBPUlRFRApCWSBBTiBBR0VOQ1kgT1IgT1JHQU5JWkFUSU9OIE9USEVSIFRIQU4gRFNVLCBZT1UgUkVQUkVTRU5UIFRIQVQgWU9VIEhBVkUKRlVMRklMTEVEIEFOWSBSSUdIVCBPRiBSRVZJRVcgT1IgT1RIRVIgT0JMSUdBVElPTlMgUkVRVUlSRUQgQlkgU1VDSApDT05UUkFDVCBPUiBBR1JFRU1FTlQuCgpEU1Ugd2lsbCBjbGVhcmx5IGlkZW50aWZ5IHlvdXIgbmFtZShzKSBhcyB0aGUgYXV0aG9yKHMpIG9yIG93bmVyKHMpIG9mIHRoZQpzdWJtaXNzaW9uLCBhbmQgd2lsbCBub3QgbWFrZSBhbnkgYWx0ZXJhdGlvbiwgb3RoZXIgdGhhbiBhcyBhbGxvd2VkIGJ5IHRoaXMKbGljZW5zZSwgdG8geW91ciBzdWJtaXNzaW9uLgo=
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