Subject
[SDU]Sciences of the Universe [physics]

Domains
Géologie, Volcanologie, Géophysique

Description

International audience Active volcanoes in the Vanuatu archipelago permanently generate infrasonic waves. Their monitoring over 1 year exhibits clear seasonal trends in the direction of arrival of the detected signals. From summer to winter the azimuth variation reaches 15°. This deviation is essentially due to the reversibility of the zonal stratospheric wind with season which strongly affects the deflection of the ray direction. A three-dimensional (3-D) ray-tracing modeling roughly explains the observed seasonal trend in the azimuth variation but underestimates its amplitude. The discrepancy between the measurements and the results of simulation is explained by undervalued wind speeds in the upper atmosphere. Infrasonic observations are used as input of an inversion scheme for adjusting the vertical structure of the wind in the upper stratosphere and mesosphere. It is shown that the mesospheric zonal winds are underestimated by at least 20 m/s throughout the year with differences reaching 50 m/s.

Keywords

Language
English (en-GB)

Creators
Le Pichon, A., Blanc, E., Drob, D., Lambotte, S., Dessa, J.X., Lardy, M., Bani, P., Vergniolle, S.

Contributors
Laboratoire de Détection et de Géophysique (CEA) (LDG) ; DAM Île-de-France (DAM/DIF) ; Direction des Applications Militaires (DAM) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction des Applications Militaires (DAM) ; Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), E. O. Hulburt Center for Space Research ; Naval Research Laboratory (NRL), Ecole et Observatoire des Sciences de la Terre (EOST) ; Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géosciences Marines (LGM) ; Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie]), Institut de Physique du Globe de Paris (IPGP) ; Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)

Sources
ISSN: 0148-0227, EISSN: 2156-2202, Journal of Geophysical Research, https://hal.science/hal-00407449, Journal of Geophysical Research, 2005, 110, pp.D13106. ⟨10.1029/2004JD005587⟩

Relation
info:eu-repo/semantics/altIdentifier/doi/10.1029/2004JD005587

Coverage
Vanuatu

Name of newspaper