| Titre | Rise of Great Lakes surface water, sinking of the upper midwest of the United States, and viscous collapse of the forebulge of the former Laurentide Ice Sheet |
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| Auteur | Argus, D F; Ratliff, B; DeMets, C; Borsa, A A; Wiese, D N; Blewitt, G; Crowley, J W ; Martens, H R; Kreemer, C; Landerer, F W |
| Source | Journal of Geophysical Research, Solid Earth vol. 125, issue 1, e2020JB019739, 2020 p. 1-16, https://doi.org/10.1029/2020JB019739 |
| Image |  |
| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200461 |
| Éditeur | Blackwell Publishing Ltd. |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1029/2020JB019739 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Province | Ontario |
| Lat/Long OENS | -94.0500 -74.9667 51.1500 39.6000 |
| Sujets | niveaux d'eau; profondeurs des eaux lacustres; eaux lacustres; lacs; bassins versants; propriétés hydrologiques; Bassin de Great Lakes ; Système de positionnement global; Hydrologie; Sciences et
technologie; Nature et environnement; géologie de l'environnement |
| Illustrations | cartes de localisation; graphiques; diagrammes |
| Diffusé | 2020 07 31 |
| Résumé | (disponible en anglais seulement)
Great Lakes water levels rose 0.7–1.5 m from 2013 to 2019, increasing surface water volume by 285 km3. Solid Earth's elastic response to the increased mass load
is nearly known: The Great Lakes floor fell 8–23 mm, and the adjacent land fell 3–14 mm. Correcting GPS measurements for this predicted elastic loading (1) straightens position-time series, making the evolution of position more nearly a constant
velocity and (2) reduces estimates of subsidence rate in Wisconsin, Michigan, and southern Ontario by 0.5–2 mm/yr, improving constraints on postglacial rebound. GPS records Wisconsin and Michigan to have subsided at 1–4 mm/yr. We find this sinking to
be produced primarily by viscous collapse of the former Laurentide ice sheet forebulge and secondarily by elastic Great Lakes loading. We infer water on land in the Great Lakes watershed to be total water change observed by GRACE minus Great Lakes
surface water smeared by a Gaussian distribution. Water stored on land each year reaches a maximum in March, 6 months before Great Lakes water levels peak in September. The seasonal oscillation of water on land in the Great Lakes basin, 100 km3 (0.20
m water thickness), is twice that in a hydrology model. In the seasons, groundwater in the Great Lakes watershed increases by 60 km3 (0.12 m) each autumn and winter and decreases by roughly an equivalent amount each spring and summer. In the long
term, groundwater volume remained constant from 2004 to 2012 but increased by 50 km3 (0.10 m) from 2013 to 2019. |
| GEOSCAN ID | 327291 |
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