Modeling Surface Mass Loading Around The Great Lakes Region
Abstract
The Great Lakes (Superior, Huron, Ontario, Michigan, and Erie) make up for one-fifth of the freshwater surface area on the Earth. Displacements at the Earth's surface are caused by any static load, including lake loading, and can be predicted by evaluating a convolution integral over the loaded region. In this study, we aim to find the range of allowable models for elasticity and density structures through the crust and upper mantle in the central U.S. constrained by observed Earth deformation from water loading in the Great Lakes. GNSS data from the Network of the Americas (NOTA; previously known as PBO) are used to estimate 3-D displacements of Earth's surface caused by lake loading. GNSS position series represent the superposition of many different signals, from which the lake-loading signal must be isolated accurately in order to infer Earth structure. We therefore model and remove predicted deformation due to soil moisture loading (NLDAS model), snow loading (SNODAS model), atmospheric-pressure loading (ECMWF model), and non-tidal oceanic loading (ECCOv4 model). Predictions are computed using a Python-based toolkit called LoadDef to model elastic deformation caused by surface mass loading on spherically symmetric bodies. Residual displacements between the best estimates of observed and predicted lake loading are assessed in the context of deficiencies in the assumed model for Earth structure, deficiencies in the assumed hydrological models, and other uncertainties in the GNSS analysis and loading predictions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMG003.0004D
- Keywords:
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- 1211 Non-tectonic deformation;
- GEODESY AND GRAVITY;
- 1217 Time variable gravity;
- GEODESY AND GRAVITY;
- 1218 Mass balance;
- GEODESY AND GRAVITY;
- 1236 Rheology of the lithosphere and mantle;
- GEODESY AND GRAVITY