Meteor Radar Temperatures Over the Brazilian Low-Latitude Sectors

Autor(es)

Lima, L. M. ^[1] ; Batista, P. P. ^[2] ; Paulino, A. R. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Paraiba, Dept Fis, Campina Grande - Brazil

^[2] Inst Nacl Pesquisas Espaciais, Div Aeron, Sao Jose Dos Campos - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS; v. 123, n. 9, p. 7755-7766, SEP 2018.
• Citações Web of Science: 2

Resumo

Meteor radar observations have been used to estimate the mesospheric temperatures at 90-km height over the Brazilian low-latitude sectors by applying gradient- and pressure-based techniques. The measurements have been taken from meteor radars operating at Cachoeira Paulista (22.7 degrees S, 45 degrees W), from 2002 to 2006, and SAo JoAo do Cariri (7.4 degrees S, 36.5 degrees W), between mid-2004 and 2008. The temperatures estimated from meteor data by the two techniques, using local models for temperature gradient and pressure, showed a good agreement with temperatures from Sounding of the Atmosphere by Broadband Emission Radiometry over both sites. The seasonal behavior of the temperatures estimated from meteor data, and from Sounding of the Atmosphere by Broadband Emission Radiometry instrument, is characterized by a semiannual oscillation (SAO) with maximum values during equinoxes, which coincide with the westward phase of the mean zonal wind as well as with SAO on diurnal tidal amplitudes over both sites. The lag phases between SAO on temperatures and on winds (or on diurnal tidal amplitudes), near equator, have been stable in time indicating a seasonal cycle and the dynamic coupling of the tropical mesosphere through nonlinear interactions between oscillations from stratosphere. Although the time series used are short to establish reliable trends or solar effects, the temperatures over Cachoeira Paulista showed a decrease between 2003 and 2006, just when F10.7 index has declined in a rate of 15.3sfu/year, while over SAo JoAo do Cariri only a slight decay has been observed on temperatures by gradient technique obtained from mid-2004 to 2008, when F10.7 decrease rate was 9.2 sfu/year. (AU)

• Processo FAPESP: 17/00590-3 - Estimativa da temperatura da mesopausa tropical a partir de medidas por radar de meteoros
• Beneficiário: Paulo Prado Batista
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Brasil