The spectral analysis of geological and geophysical data has been a fundamental tool in understanding Earth’s processes. We present a Fortran 90 library for multitaper spectrum estimation, a state-of-the-art method that has been shown to outperform the standard methods. The library goes beyond power spectrum estimation and extracts for the user more information including confidence intervals, d...

A major source of unwanted signals in seismic data recorded for geophysical exploration is the presence of guided waves which are scattered near the surface of the earth. These waves do not contain information on the structure of the deeper subsurface and should therefore be removed. In this paper we derive a method for removing this type of waves based on a modal expansion. The problem of ndin...

Statistical bounds controlling the total fluctuations in mean and variance about a basic steady 6 state solution are developed for the truncated barotropic flows over topography. Statistical ensemble predic7 tion is an important topic in weather and climate research. Here the evolution of an ensemble of trajectories 8 is considered in the statistical instability analysis and is compared and con...

We present a Lagrangian particle/panel method for geophysical fluid flow described by the barotropic vorticity equations on a rotating sphere. The particles carry vorticity and the panels are used in discretizing the Biot-Savart integral for the velocity. Adaptive panel refinement and a new Lagrangian remeshing scheme are applied to reduce the computational cost and maintain accuracy as the flo...

S U M M A R Y The power spectral density of geophysical signals provides information about the processes that generated them. We present a new approach to determine power spectra based on Thomson’s multitaper analysis method. Our method reduces the bias due to the curvature of the spectrum close to the frequency of interest. Even while maintaining the same resolution bandwidth, bias is reduced ...

Recently developed methods for inferring abrupt changes in data series enable such change points in time or space to be identified, and also allow us to estimate noise levels of the observed data. The inferred probability distributions of these parameters provide insights into the capacity of the observed data to constrain the geophysical analysis and hence the magnitudes, and likely sources, o...

The correct positioning of deep wells to monitor groundwater and entrained contaminants is greatly aided by using remote sensing methods. The geologic setting at the Anniston Army Depot (ANAD) consists of a sequence of fractured dolostones and clastic rocks that have been thrust-faulted, creating a highly complex and heterogeneous aquifer. The drilling of deep bedrock groundwater monitoring wel...

Inverse problems are usually ill-posed in such a way that it is necessary to use some method to reduce their deficiencies. The method that we choose is the regularization by derivative matrices. There is a crucial problem in regularization, which is the selection of the regularization parameter λ. In this work we use generalized cross validation (GCV) as a tool for the selection of λ. GCV was p...

A b s t r a e t A method is described for modifying the velocity field in geophysical fluid models so as to enforce the continuity equation. A corrective mass flux is introduced, which derives from a scalar potential, The latter is the solution of a Poisson problem which is formulated in such a way that a suitable lmrm of the corrective velocity be minimum. It is seen that a generalised vertica...

Neural networks are increasingly popular in geophysics. Because they are universal approximators, these tools can approximate any continuous function with an arbitrary precision. Hence, they may yield important contributions to finding solutions to a variety of geophysical applications. However, knowledge of many methods and techniques recently developed to increase the performance and to facil...