ESR N°8: Monitoring water storage changes with a new portable absolute quantum gravimeter

Research Fellow: Anne-Karin Cooke

Profile

hosted by µQuans (until June 2019) and University of Montpellier (since June 2019)

Supervisors
Cédric Champollion Géosciences Montpellier
Pierre Vermeulen, µQuans

Secondments
University of Montpellier (2017, 2018, 2019)

Objectives

The objective is the field validation of the first AQG against the most accurate gravimeters located at fixed stations at H+ Larzac and LSBB sites. The AQG will be used to estimate the contribution of different water storage reservoirs in complement to vertically resolved complementary measurements (ERT, RMP, borehole logging) and later coupled with soil moisture and gravity measurements the HOBE observatory.

Project Description

Gravity measurements are pertinent to monitor water balance from local to basin scale and can provide accurate constrains on the water storage dynamics of subsurface reservoirs.  One major characteristic of gravity measurements is the integration of all water masses across scales: gravity variations can be the effect of continental scale soil humidity or aquifer (such as seen by GRACE measurements) and of local effects (such as the umbrella effect of a building or reservoir heterogeneities).

This technique can provide an estimation of the water storage spatial variability at kilometer scale with an integration scale of about 100 m. μQuans is developing a new absolute quantum gravimeter (AQG), fast and transportable (sensor ~30 kg). The AQG is a real technological breakthrough compared to current portable gravimeters, which provide relative measurements. It will allow a more efficient and precise mapping of gravity in space and time.

Tasks & Methodology

My task is to perform the field validation of the first AQG against the most accurate gravimeters located at fixed stations.

Afterwards the AQG will be used to estimate the contribution of different water storages in complement to other (hydro-)geophysical methods.  An additional task are numerical modelling studies on the potential of vertical gravity gradient monitoring for the detection of significant hydrological signals, based on gradient time series.

Data & Datasets

H+ database

Dissemination and communication

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2019

Presentation at the EGU General Assembly, Vienna (Austria): “Potential Impact of groundbased gravity gradiometer for subsurface reservoir monitoring

2018

  • Poster presentations at two doctoral school days:
    • 22/03/2018 Montpellier: J​ournée de Doctorants: Institut Montpelliérain de l’Eau et de L’Environnement (IM2E)​ ( http://www.im2e.org/)
    • 18/05/2018 Montpellier: Journée des doctorants Géosciences Montpellier

Several introduction courses at doctoral school GAIA (Umontpellier) and a day seminar on ethics in science (also by GAIA)

(Formation à l’éthique de la recherche et à l’intégrité scientifique)

Poster for the 4th Cargèse Summer School: “On the potential of vertical gravity gradient monitoring for hydrological signal detection