Tidal calibration of borehole strain meters: Removing the effects of small-scale inhomogeneity

1996 ◽  
Vol 101 (B11) ◽  
pp. 25553-25571 ◽  
Author(s):  
R. H. G. Hart ◽  
M. T. Gladwin ◽  
R. L. Gwyther ◽  
D. C. Agnew ◽  
F. K. Wyatt
Keyword(s):  
Small Scale ◽  
Scale Inhomogeneity

Chemistry, small-scale inhomogeneity, and formation of moldavites as condensates from sands vaporized by the Ries impact

2005 ◽  
Vol 69 (23) ◽  
pp. 5611-5626 ◽  
Author(s):  
Wolf von Engelhardt ◽  
Christoph Berthold ◽  
Thomas Wenzel ◽  
Thomas Dehner
Keyword(s):  
Small Scale ◽  
Scale Inhomogeneity

scholarly journals Wind-profiler observations of gravity waves produced by convection at mid-latitudes

2006 ◽  
Vol 6 (10) ◽  
pp. 2825-2836 ◽  
Author(s):  
Y. G. Choi ◽  
S. C. Lee ◽  
A. J. McDonald ◽  
D. A. Hooper
Keyword(s):  
Gravity Waves ◽  
Vertical Velocity ◽  
Small Scale ◽  
Wind Profiler ◽  
Convective Activity ◽  
Velocity Fluctuations ◽  
Short Period ◽  
Horizontal Momentum ◽  
Scale Inhomogeneity

Abstract. This work presents a case study which includes regions of large rapidly varying vertical velocities observed by a VHF wind-profiler at Aberystwyth (52.4° N, 4.1° W). Analysis indicates that this region is associated with gravity waves above the tropopause level and simultaneous regions of convective activity below the tropopause level. This case study also suggests that convective activity can be identified effectively by finding periods of large uncertainties on the derived velocities. These regions are hypothesized to be related to regions of small-scale inhomogeneity in the wind field. Examination suggests that the large vertical velocity fluctuations above these convective regions are short period gravity wave packets as expected from theory. In addition the vertical flux of the horizontal momentum associated with the gravity waves also displays the pattern of reversal observed in previous studies.

scholarly journals Stable spike clusters for the one-dimensional Gierer–Meinhardt system

2016 ◽  
Vol 28 (4) ◽  
pp. 576-635 ◽  
Author(s):  
JUNCHENG WEI ◽  
MATTHIAS WINTER
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Small Scale ◽  
Biologically Relevant ◽  
Formula Group ◽  
Group A ◽  
Scale Inhomogeneity ◽  
The One ◽  
Image Position ◽  
Small Scale Structures

We consider the Gierer–Meinhardt system with precursor inhomogeneity and two small diffusivities in an interval $$\begin{equation*} \left\{ \begin{array}{ll} A_t=\epsilon^2 A''- \mu(x) A+\frac{A^2}{H}, &x\in(-1, 1),\,t>0,\\[3mm] \tau H_t=D H'' -H+ A^2, & x\in (-1, 1),\,t>0,\\[3mm] A' (-1)= A' (1)= H' (-1) = H' (1) =0, \end{array} \right. \end{equation*}$$$$\begin{equation*}\mbox{where } \quad 0<\epsilon \ll\sqrt{D}\ll 1, \quad \end{equation*}$$$$\begin{equation*} \tau\geq 0 \mbox{ and $\tau$ is independent of $\epsilon$. } \end{equation*}$$ A spike cluster is the combination of several spikes which all approach the same point in the singular limit. We rigorously prove the existence of a steady-state spike cluster consisting of N spikes near a non-degenerate local minimum point t0 of the smooth positive inhomogeneity μ(x), i.e. we assume that μ′(t0) = 0, μ″(t0) > 0 and we have μ(t0) > 0. Here, N is an arbitrary positive integer. Further, we show that this solution is linearly stable. We explicitly compute all eigenvalues, both large (of order O(1)) and small (of order o(1)). The main features of studying the Gierer–Meinhardt system in this setting are as follows: (i) it is biologically relevant since it models a hierarchical process (pattern formation of small-scale structures induced by a pre-existing large-scale inhomogeneity); (ii) it contains three different spatial scales two of which are small: the O(1) scale of the precursor inhomogeneity μ(x), the $O(\sqrt{D})$ scale of the inhibitor diffusivity and the O(ε) scale of the activator diffusivity; (iii) the expressions can be made explicit and often have a particularly simple form.

‘Acceleration’ from small-scale inhomogeneity?

2012 ◽  
pp. 416-444
Author(s):  
George Ellis ◽  
Roy Maartens ◽  
Malcolm MacCallum
Keyword(s):  
Small Scale ◽  
Scale Inhomogeneity

3D modeling of electromagnetic gradiometer data — A numerical study on tunnel detection

Geophysics ◽  
2021 ◽  
Vol 86 (3) ◽  
pp. WB79-WB88
Author(s):  
Rahul Dehiya
Keyword(s):  
3D Modeling ◽  
Impact Analysis ◽  
Numerical Study ◽  
Depth Estimation ◽  
Detailed Comparison ◽  
Small Scale ◽  
Response Curves ◽  
Parallel Configuration ◽  
Scale Inhomogeneity ◽  
The Impact

I have examined the possibility of using a 3D modeling algorithm in studying tunnel detectability using the electromagnetic gradiometer (EMG) response. A detailed comparison of different source-receiver configurations reveals that the EMG response is stronger for a configuration when the transmitter and receiver are orthogonal to each other than the parallel configurations. Orthogonal configurations perform better at a relatively lower frequency than the parallel configuration. The EMG response is enhanced with the broadside offset defined as the distance between transmitter and receiver pair. The response of a tunnel is generally weak; consequently, deviation from the configuration in which both receivers are equidistant from the transmitter masks the response of a tunnel. The impact analysis of tunnel-floor conductivity revealed that a one-order-higher conductive floor does not change the behavior of response compared to a tunnel without a conductive floor. However, the two-order-higher conductive floor changes the shape of the response curves, yet the change in the magnitude is not significant. The presence of a metal conductor substantially enhances the response of an EMG system. The parallel configuration is more suitable for the depth estimation of the tunnel than the orthogonal configuration. The distortion in the EMG response due to the heterogeneity in the case of an orthogonal configuration depends on the broadside offset. For a zero broadside offset, the response is severely distorted by the small-scale inhomogeneity. For a broadside offset such as 20 m, the impact of small-scale inhomogeneity is almost invisible.

scholarly journals Deciphering the Role of Small-Scale Inhomogeneity on Geophysical Flow Structuration: A Stochastic Approach

2020 ◽  
Vol 50 (4) ◽  
pp. 983-1003 ◽  
Author(s):  
Werner Bauer ◽  
Pranav Chandramouli ◽  
Bertrand Chapron ◽  
Long Li ◽  
Etienne Mémin
Keyword(s):  
Stochastic Approach ◽  
Stokes Drift ◽  
Spatial Inhomogeneity ◽  
Small Scale ◽  
Stochastic Representation ◽  
Flow Components ◽  
Scale Inhomogeneity ◽  
Induced Velocity ◽  
Geophysical Flow ◽  
Wave Induced

AbstractAn important open question in fluid dynamics concerns the effect of small scales in structuring a fluid flow. In oceanic or atmospheric flows, this is aptly captured in wave–current interactions through the study of the well-known Langmuir secondary circulation. Such wave–current interactions are described by the Craik–Leibovich system, in which the action of a wave-induced velocity, the Stokes drift, produces a so-called “vortex force” that causes streaking in the flow. In this work, we show that these results can be generalized as a generic effect of the spatial inhomogeneity of the statistical properties of the small-scale flow components. As demonstrated, this is well captured through a stochastic representation of the flow.

scholarly journals Wind-profiler observations of gravity waves produced by convection at mid-latitudes

2005 ◽  
Vol 5 (6) ◽  
pp. 11029-11054
Author(s):  
Y. G. Choi ◽  
S. C. Lee ◽  
A. J. McDonald ◽  
D. A. Hooper
Keyword(s):  
Gravity Waves ◽  
Vertical Velocity ◽  
Small Scale ◽  
Wind Profiler ◽  
Convective Activity ◽  
Velocity Fluctuations ◽  
Short Period ◽  
Horizontal Momentum ◽  
Scale Inhomogeneity

Abstract. This work presents a case study which includes regions of large rapidly varying vertical velocities observed by a VHF wind-profiler at Aberystwyth (52.4° N, 4.1° W). Analysis indicates that this region is associated with gravity waves above the tropopause level and simultaneous regions of convective activity below the tropopause level. This case study also suggests that convective activity can be identified effectively by finding periods of large uncertainties on the derived velocities. These regions are hypothesized to be related to regions of small-scale inhomogeneity in the wind field. Examination suggests that the large vertical velocity fluctuations above these convective regions are short period gravity wave packets as expected from theory. In addition the vertical flux of the horizontal momentum associated with the gravity waves also displays the pattern of reversal observed in previous studies.

Reasons to strike first

2019 ◽  
Vol 42 ◽  
Author(s):  
William Buckner ◽  
Luke Glowacki
Keyword(s):  
Intergroup Conflict ◽  
Small Scale

Abstract De Dreu and Gross predict that attackers will have more difficulty winning conflicts than defenders. As their analysis is presumed to capture the dynamics of decentralized conflict, we consider how their framework compares with ethnographic evidence from small-scale societies, as well as chimpanzee patterns of intergroup conflict. In these contexts, attackers have significantly more success in conflict than predicted by De Dreu and Gross's model. We discuss the possible reasons for this disparity.

Sign in / Sign up

Export Citation Format

Share Document