ISSN:
1365-246X
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Geosciences
Notes:
Heat transport by large-scale groundwater movement, reported for a number of sedimentary basins, may cause sufficiently severe perturbations to the thermal regime that the patterns of near surface heat-flow density (HFD) may be very different from that of the desired deep-seated conductive HFD. However, a good interpretation of the HFD data from perturbed areas is possible when knowledge of both the thermal and hydrological regimes is available, but there are three major difficulties. First, the thermal and hydrological data are often noisy; second, the two regimes are closely coupled; third, the deep-seated, or basal HFD is a very uncertain boundary condition. In this paper, we present a method, currently in 2-D, that inverts the noisy thermal and hydrological data simultaneously, and is able to resolve uncertain boundary conditions. The temperature and hydraulic head and the thermal conductivities and intrinsic permeabilities of the subsurface materials are first parameterized with an isoparametric finite element model. The parameters are then estimated using a Bayesian type non-linear inverse method. In the finite element formulation, the boundary heat and water fluxes are linearly transformed into an equivalent nodal flow (ENF) vector, which is updated together with the estimated parameters. Another (linear) inversion of the updated ENF components gives the updated boundary fluxes, with variances. The applications of the boundary flux updating technique to the determination of the background HFD in hydrologically active areas are illustrated with numerical examples.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-246X.1989.tb05514.x
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