Hybrid gravimetry as a tool to spatialize water storage fluctuations in mountainous catchments. The case of the Strengbach catchment, Vosges mountains, France.
Abstract
Due to their strong topography, the hydrological functioning of mountainous catchments is still a challenge to be assessed. Nevertheless, water resource management is a key issue in mountainous areas, especially in the context of climate change.
The spatial-integrative nature of gravimetric measurements makes them sensitive to water storage fluctuations around the observation points. Thus, gravimetry is a key method to investigate water storage fluctuations at middle scale. At the Strengbach catchment in the Vosges mountains (France) continuous monitoring of gravity fluctuations is provided by a superconducting gravimeter iGrav#30 since June 2017. In addition, the continuous monitoring of meteo-hydrological fluxes allows to compute the hydrological budget of the catchment. As a first step, we distributed the corresponding amount of water along a single layer covering the surface topography and computed the associated gravity response, which shows strong agreement with iGrav#30 observed gravity hence proving that gravity is a good proxy of space-averaged water storage fluctuations. In a next step we choose to distribute water using the low dimensional hydrological model NIHM (Normally Integrated Hydrological Model, Jeannot et al., 2018). NIHM reproduces the outflow measured at the catchment outlet but remains poorly constrained in terms of water storage spatialization due to the lack of reliable piezometric observations. One of our objectives is to calibrate NIHM using hybrid gravimetry where relative gravity measurements are done in repeated surveys on a network of stations using the superconducting gravimeter as reference station. The gravity response of NIHM is computed for the entire catchment and is compared with the observed gravity map resulting from our hybrid gravity approach.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H41B..02C
- Keywords:
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- 1217 Time variable gravity;
- GEODESY AND GRAVITY;
- 1218 Mass balance;
- GEODESY AND GRAVITY;
- 1835 Hydrogeophysics;
- HYDROLOGY;
- 1895 Instruments and techniques: monitoring;
- HYDROLOGY