| Titre | Assessing global present-day surface mass transport and glacial isostatic adjustment from inversion of geodetic observations |
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| Auteur | Jiang, Y ; Wu, X;
van den Broeke, M; Munneke, P K; Simonsen, S; van der Wal, W; Vermeersen, B |
| Source | Geophysical Research Letters vol. 126, issue 5, e2020JB020713, 2021., https://doi.org/10.1029/2020JB020713  Accès ouvert |
| Image |  |
| Année | 2021 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190309 |
| Éditeur | Blackwell Publishing Ltd. |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1029/2020JB020713 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Lat/Long OENS | -180.0000 180.0000 90.0000 -90.0000 |
| Sujets | géodésie; gravité; Sciences et technologie |
| Illustrations | cartes de localisation; diagrammes; tableaux |
| Programme | Géosciences de changements climatiques Infrastructure côtière |
| Diffusé | 2021 04 22 |
| Résumé | (disponible en anglais seulement)
Satellite gravity provide unprecedented spatial and temporal coverage to monitor present-day mass transport (PDMT). However, they contain signals from past ice
sheet melting, preventing us from eLong-term monitoring of global mass transport within the Earth system improves our ability to mitigate natural hazards and better understand their relations to climate change. Satellite gravity is widely used to
monitor surface mass variations for its unprecedented spatial and temporal coverage. However, the gravity data contain signals from visco-elastic deformation in response to past ice sheet melting, preventing us from extracting signals of present-day
surface mass trend (PDMT) directly. Here we present a global inversion scheme that separates PDMT and visco-elastic glacial isostatic adjustment (GIA) signatures by combining satellite gravimetry with satellite altimetry and ground observations. Our
inversion provides global dual data coverage that enables a robust separation of PDMT and GIA spherical harmonic coefficients. It has the advantage of providing estimates of Earth's long wavelength deformation signatures and their uncertainties. Our
GIA result, along with its uncertainty estimates, can be used in future GRACE processing to better assess the impact of GIA on surface mass change. Our GIA estimates include a rapid GIA uplift in the Southeast Alaska and the Amundsen Sea Embayment,
due to the visco-elastic response to recent glacial unloading. We estimate the average surface mass change rate from 2002–2010 to be -203 ± 3 GT·a-1 in Greenland, -126 ± 18 GT·a-1 in Antarctica and, -62 ± 5 GT·a-1 in Alaska. The GIA low degree
spherical harmonic coefficients are sensitive to rheological properties in Earth's deep interior. Our low-degree GIA estimates include geocenter motion and (Formula presented.) which provide unique constraints to understand Earth's lower mantle and
ice history.xtracting signals of current surface mass change directly from data. Here we present a global inversion scheme that separates PDMT and glacial isostatic adjustment (GIA) by combining satellite gravimetry with altimetry and ground
observations. Our inversion provides global dual data coverage that enables a robust separation of PDMT and GIA low-degree spherical harmonic coefficients. We find rapid GIA uplift in the Southeast Alaska and the Amundsen Sea Embayment, likely due to
the visco-elastic rebound in response to recent glacial unloading. We estimate the average mass change rate to be -198±4 GT/a in Greenland, -134±23 GT/a in Antarctica and -61±5 GT/a in Alaska from 2002 - 2010. Our low-degree GIA estimates including
geocenter motion provide unique constraints to understand Earth's lower mantle and ice history. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Les échanges de masse en surface entre les «sphères» de la Terre - atmosphère, hydrosphère, cryosphère, biosphère et pédosphère sont énormes. La
surveillance de l'évolution des masses superficielles aide à comprendre le changement climatique et à atténuer les effets dangereux tels que les sécheresses extrêmes et les inondations. Les mesures du changement de masse superficielle sont perturbées
par des processus souterrains, tels que l'écoulement du manteau sous la croûte terrestre. Souvent, un modèle est introduit pour corriger les signaux sous-marins issus des observations, introduisant des erreurs non modélisées dans les estimations de
masse surfacique. Nous utilisons une méthode basée sur les données pour extraire les changements de masse de surface actuels directement à partir des données. Nous obtenons une image plus précise des processus souterrains, qui sont principalement
causés par la réponse visqueuse de la Terre à la fonte des glaces. Nous constatons que la croûte terrestre rebondit plus rapidement et plus fortement après la fonte des glaciers que nous l'avions imaginé auparavant, en particulier dans les endroits
où la croûte est plus faible. |
| GEOSCAN ID | 315673 |
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