Reshaping the Critical Zone with Hydrogeodesy
Abstract
This document summarizes the research activities I have been leading during the last
eight years within Geosciences Rennes and the "Environmental Dynamics" team. The
developments undertaken are rooted in my doctoral work (Longuevergne, 2008) ; they
have evolved at the rhythm of reflections and experiences, meetings and discussions.
They have been enhanced by close team-wide interactions in Rennes, and collaborations
with several researchers in France, Europe and all over the world. The originality of the
research I have conducted owes a lot to constructive interferences with researchers from
other disciplines, but also from a focused work specific topics.
The main contribution lies on the development and qualification of geodetic instruments
as tools for hydrology, mainly driven by an instrumental and experimental
approach. The first chapter introduces the concept of the Critical Zone, which is reinterpreted
as a dynamic notion to better include the full role of groundwater within the
water cycle on a wide range of temporal scales. As water is in permanent contact with
rock, I also underline the physical interactions between the "Critical Zone" and the "Solid
Earth", suggesting the opportunity to fertilize the reciprocal input of both discipline.
Among the Solid Earth tools, geodesy offers a wide range of highly accurate instruments,
stable and well calibrated, which can be used to capture the spatio-temporal
redistribution of water in the subsurface, from surface and space-borne observations.
The second chapter explores their ability to estimate water storage and pressure changes
and bring insights into the heterogeneous, and hidden Critical Zone. Quantifying water
transfers in the Earth’s subsurface is motivated by basic scientific questions and major
challenges, such as the management of (water) resources, the exploitation and storage of
resources and energy, the sensitivity of the subsurface to deformation, the understanding
of the links between the external and internal envelopes of the Earth.
Then, the future challenges I want to explore are described in the third chaper, namely
(1) the non-linear nature of fracture flow and transfer processes ; (2) the imaging
of subsurface flow and their control by heterogeneities ; (3) the full representation of the
groundwater role in the Earth’s climatic system ; and (4) the inter-relationship between
the different compartments composing ecosystems, through a large-scale experiment.
Domains
Earth Sciences
Origin : Files produced by the author(s)
Loading...