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Atmospheric angular momentum related to Earth rotation studies: history and modern developments / David A. Salstein (2019) 

Public Titre : Atmospheric angular momentum related to Earth rotation studies: history and modern developments Type de document : Article/Communication Auteurs : David A. Salstein, Auteur Editeur : Paris, Meudon et Nançay : Observatoire de Paris Année de publication : 2019 Conférence : JSRST 2019, Journées systèmes de référence spatio-temporels, Astrometry, Earth Rotation, and Reference Systems in the GAIA era 07/10/2019 09/10/2019 Paris France OA Proceedings Importance : pp 209 - 213 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie [Termes IGN] moment cinétique atmosphérique [Termes IGN] rotation de la Terre Résumé : (auteur) It was noted some time ago that the angular momentum of the atmosphere varies, both regionally as well as in total. Given the conservation of angular momentum in the Earth system, except for known external torques, such variability implies transfer of the angular momentum across the atmosphere’s lower boundary. As nearly all is absorbed by the Earth below, the solid Earth changes its overall rotation from this impact. Due to the large difference between in the moments of inertia of the atmosphere and Earth, relatively big differences in the atmosphere are translated as relatively very small differences in the Earth, measurable as changes in Earth rotation rate, and polar motion. The atmospheric angular momentum (AAM) is that due to the motion of the winds and to the changes in mass distribution, closely related to the atmosphere pressure patterns; its variability in the atmosphere is mirrored in the Earth rotation rate and polar motion. This connection between the global solid Earth properties and the global and regional atmosphere on a number of time scales, especially seasonal and interannual, was much appreciated by Barbara Kolaczek, with Jolanta Nastula, at the Space Research Center in Warsaw, and this was a subject of our collaborative studies. Many calculations were made of atmospheric angular momentum, leading to a service under the Global Geophysical Fluids Center of the IERS based on calculations using both operational meteorological series, determined for weather forecasting purposes, and retrospective analyses of the atmosphere. Theoretical development of the connection between the AAM, Earth rotation/polar motion, and also the angular momentum of the other geophysical fluids occurred at the same time that space-based observations and enhanced computer power were allowing improved skills for both weather analysis and forecasting. Hence better determination of the AAM became possible, which could be used as a measure for forecasting Earth rotation. Today we are looking at the atmosphere in combination with the ocean and other fluids, and also assessing the implications of climate variability on Earth rotation through climate model research. According to models of the Earth system, significant changes in winds appear to be a possible result of climate change, with implications for the Earth rotation parameters. Numéro de notice : C2019-076 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Communication DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100193

Documents numériques

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Combination of modeled short-term angular momentum function forecasts from atmosphere, ocean, and hydrology with 90-day EOP predictions / Robert Dill in Journal of geodesy, vol 87 n° 6 (June 2013)  

Public [article]  inJournal of geodesy > vol 87 n° 6 (June 2013) . - pp 567 - 577 Titre : Combination of modeled short-term angular momentum function forecasts from atmosphere, ocean, and hydrology with 90-day EOP predictions Type de document : Article/Communication Auteurs : Robert Dill, Auteur ; H. Dobslaw, Auteur ; M. Thomas, Auteur Année de publication : 2013 Article en page(s) : pp 567 - 577 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] moment cinétique atmosphérique [Termes IGN] moment cinétique océanique [Termes IGN] orientation de la Terre [Termes IGN] prévision Résumé : (Auteur) Angular momentum forecasts for up to 10 days into the future, modeled from predicted states of the atmosphere, ocean and continental hydrosphere, are combined with the operational IERS EOP prediction bulletin A to reduce the prediction error in the very first day and to improve the subsequent 90-day prediction by exploitation of the revised initial state and trend information. EAM functions derived from ECMWF short-range forecasts and corresponding LSDM and OMCT simulations can account for high-frequency mass variations within the geophysical fluids for up to 7 days into the future primarily limited by the accuracy of the forecasted atmospheric wind fields. Including these wide-band stochastic signals into the first days of the 90-day statistical IERS predictions reduces the mean absolute prediction error even for predictions beyond day 10, especially for polar motion, where the presently used prediction approach does not include geophysical fluids data directly. In a hindcast experiment using 1 year of daily predictions from May 2011 till July 2012, the mean prediction error in polar motion, compared to bulletin A, is reduced by 32, 12, and 3 % for prediction days 10, 30, and 90, respectively. In average, the prediction error for medium-range forecasts (30–90 days) is reduced by 1.3–1.7 mas. Even for UT1-UTC, where AAM forecasts are already included in IERS bulletin A, we obtain slight improvements of up to 5 % (up to 0.5 ms) after day 10 due to the additional consideration of oceanic angular momentum forecasts. The improved 90-day predictions can be generated operationally on a daily basis directly after the publication of the related IERS bulletin A product finals2000A daily. Numéro de notice : A2013-340 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-013-0631-6 Date de publication en ligne : 17/03/2013 En ligne : https://doi.org/10.1007/s00190-013-0631-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32478 [article]

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High-resolution atmospheric angular momentum functions related to Earth rotation parameters during CONT08 / Daniel Gambis in Journal of geodesy, vol 85 n° 7 (July 2011)  

Public [article]  inJournal of geodesy > vol 85 n° 7 (July 2011) . - pp 435 - 441 Titre : High-resolution atmospheric angular momentum functions related to Earth rotation parameters during CONT08 Type de document : Article/Communication Auteurs : Daniel Gambis, Auteur ; David A. Salstein, Auteur ; S. Lambert, Auteur Année de publication : 2011 Article en page(s) : pp 435 - 441 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] analyse comparative [Termes IGN] données GPS [Termes IGN] données ITGB [Termes IGN] moment cinétique atmosphérique [Termes IGN] rotation de la Terre Résumé : (Auteur) Due to the temporal resolution of available numerical weather analyses, the effect of the atmosphere on Earth rotation at daily and sub-daily periods is usually investigated using 6-hourly atmospheric angular momentum (AAM) functions. During the period of CONT08, however, atmospheric analysis data were provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) also on an hourly basis. In this paper, we, therefore, determine two sets of AAM functions from ECMWF data—one for CONT08 with hourly resolution and one for the year 2008 with 6-hourly resolution. The comparisons of the AAM functions to high-resolution Earth rotation parameters (ERP) from VLBI and GPS observations are carried out in the frequency domain. Special attention is paid to the preparation of the high-resolution data sets for the geodetic purposes, as there are jump discontinuities at 12 h intervals. Hence, the hourly AAM functions need to be concatenated. The revised functions yield much smaller amplitudes than their 6-hourly counterparts, as can be seen from the equatorial and the axial frequency spectra of atmospheric excitation in Earth rotation. This decrease of spectral power in the hourly AAM functions is found to be associated with a strong counteraction of pressure and wind terms, which originates from atmospheric circulation on short time scales. The results are compared to previous findings published by Brzezin'ski and Petrov (IERS Tech Note 28:53–60, 2000) based on the data from the U.S. National Centers for Environmental Prediction (NCEP). Numéro de notice : A2011-332 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-011-0458-y Date de publication en ligne : 27/04/2011 En ligne : https://doi.org/10.1007/s00190-011-0458-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31111 [article]

Exemplaires(1)

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An improved empirical model for the effect of long-period ocean tides on polar motion / Richard S. Gross in Journal of geodesy, vol 83 n° 7 (July 2009)  

Public [article]  inJournal of geodesy > vol 83 n° 7 (July 2009) . - pp 635 - 644 Titre : An improved empirical model for the effect of long-period ocean tides on polar motion Type de document : Article/Communication Auteurs : Richard S. Gross, Auteur Année de publication : 2009 Article en page(s) : pp 635 - 644 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse diachronique [Termes IGN] axe de rotation de la Terre [Termes IGN] marée océanique [Termes IGN] modèle dynamique [Termes IGN] moment cinétique atmosphérique [Termes IGN] moment cinétique océanique [Termes IGN] mouvement du pôle Résumé : (Auteur) Because the tide-raising potential is symmetric about the Earth’s polar axis it can excite polar motion only by acting upon non-axisymmetric features of the Earth like the oceans. In fact, after removing atmospheric and non-tidal oceanic effects, polar motion excitation observations show a strong fortnightly tidal signal that is not completely explained by existing dynamical and empirical ocean tide models. So a new empirical model for the effect of the termensual (Mtm and mtm), fortnightly (Mf and mf), and monthly (Mm) tides on polar motion is derived here by fitting periodic terms at these tidal frequencies to polar motion excitation observations that span 2 January 1980 to 8 September 2006 and from which atmospheric and non-tidal oceanic effects have been removed. While this new empirical tide model can fully explain the observed fortnightly polar motion excitation signal during this time interval it would still be desirable to have a model for the effect of long-period ocean tides on polar motion that is determined from a dynamical ocean tide model and that is therefore independent of polar motion observations. Copyright Springer Numéro de notice : A2009-303 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-008-0277-y Date de publication en ligne : 28/10/2008 En ligne : https://doi.org/10.1007/s00190-008-0277-y Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29933 [article]

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Interactions terre-atmosphère et rotation de la terre / Olivier de Viron in Géomatique expert, n° 63 (01/06/2008)

Public [article]  inGéomatique expert > n° 63 (01/06/2008) . - pp 20 - 24 Titre : Interactions terre-atmosphère et rotation de la terre Type de document : Article/Communication Auteurs : Olivier de Viron, Auteur Année de publication : 2008 Article en page(s) : pp 20 - 24 Langues : Français (fre) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] moment cinétique atmosphérique [Termes IGN] nutation [Termes IGN] précession [Termes IGN] rotation de la Terre [Termes IGN] système de référence mondial Résumé : (Auteur) Quels sont les phénomènes qui entrent en jeu dans la rotation de la Terre, et quel est leur impact sur la durée du jour et le système de référence terrestre ? Réponse d'Olivier de Viron, de l'Institut de Physique du Globe. Copyright CiMax Numéro de notice : A2008-203 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29198 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
265-08041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Interaction Terre Atmosphère et rotation de la Terre / Olivier de Viron (2007) 

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Atmosphärische und ozeanische Einflüsse auf die Rotation der Erde - Nummerische Untersuchungen mit einem dynamischen Erdsystemmodell / Florian Seitz (2004)

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Earth orientation, reference frames and atmospheric excitation functions submitted for the 1994 IERS annual report / Patrick Charlot (1995)

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Earth orientation, references frames and atmospheric excitation functions submitted for the 1993 IERS annual report / Patrick Charlot (1994)

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Earth orientation, reference frames and atmospheric excitation functions submitted for the 1992 IERS annual report / Patrick Charlot (1993)

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Earth orientation, reference frames and atmospheric excitation functions submitted for the 1991 IERS annual report / Patrick Charlot (1992)

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Annual report for 1989 International Earth Rotation Service (IERS), 2. Earth orientation and reference frame determinations, atmospheric excitation functions, up to 1989, annex to the IERS annual report for 1989 / International Earth Rotation and Reference Systems Service (1990)

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Prediction of polar motion from air and water excitations / J. Vondrak (1989)

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Figure and dynamics of the Earth, Moon and planets: proceedings of the international symposium, Prague, 1986, 2. Tome 2 / P. Holota (1987)

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