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Wavelet filter analysis of local atmospheric pressure effects on gravity variations / X.G. Hu in Journal of geodesy, vol 79 n° 8 (November 2005)  

Public [article]  inJournal of geodesy > vol 79 n° 8 (November 2005) . - pp 447 - 459 Titre : Wavelet filter analysis of local atmospheric pressure effects on gravity variations Type de document : Article/Communication Auteurs : X.G. Hu, Auteur ; L.T. Liu, Auteur ; et al., Auteur Année de publication : 2005 Article en page(s) : pp 447 - 459 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] anomalie de pesanteur [Termes IGN] champ de pesanteur local [Termes IGN] Chine [Termes IGN] filtrage du signal [Termes IGN] fonction harmonique [Termes IGN] gravimètre supraconducteur [Termes IGN] image multibande [Termes IGN] levé gravimétrique [Termes IGN] ondelette [Termes IGN] pression atmosphérique [Termes IGN] saison Résumé : (Auteur) An efficient method is proposed for the analysis of atmospheric pressure effects on gravity variations. It processes gravity variations and pressure signals using an orthogonal filter bank derived from high-degree Daubechies wavelets. The method introduces the atmospheric pressure admittance, which is both time- and frequency-dependent, and thus provides more information about when and how the frequency components in the pressure signal influence gravity variations. We demonstrate the efficiency of the wavelet method by applying it to observations from the Wuhan (China) superconducting gravimeter station. The analysis of gravity and pressure signals in 14 sub-bands with different bandwidths covering a frequency range from 0.176 to 720cpd (cycles per day) reveals that local atmospheric pressure fluctuations start to induce obvious effects on gravity variations in the seismic band 0.52-1.04 mHz (periods 16 to 32 min) and highly cor-relate with gravity variation in the long-period seismic mode band 0.26-0.52 mHz (periods 32-64 min). The harmonics of solar heating-induced atmospheric tides play a leading role in interfering with the variation of gravity residuals in the frequency band 0.704-11.25 cpd (periods 128 min to 1.42 day). Local atmospheric pressure effects on gravity variation are very strong in the frequency band 0.176-0.704cpd (periods 1.42-5.69 day). Accurately filtering quarter-diurnal tides into a narrow band further demonstrates the efficiency of the wavelet method. After removing secular gravity changes and long-period atmospheric pressure variations, we show that there are obvious variations of local pressure admittance on time scales of hours to days. We also reveal seasonal variability of pressure admittances in the band 0. 176-0.352 cpd (periods 2.84-5.69 day) after removing the effects of solar heating atmospheric tides. Numéro de notice : A2005-461 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-005-0486-6 En ligne : https://doi.org/10.1007/s00190-005-0486-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27597 [article]

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