Miracle-dz/UniFAR-FTUs huggingface dataset:
Degree‐2 pattern of attenuation structure in the upper mantle from apparent complex frequency measurements of fundamental spheroidal modes

The authors present preliminary results of an analysis of global lateral variations in elastic and anelastic structure of the upper mantle. Using the Sompi method, they have analyzed IDA records to measure apparent complex frequencies of fundamental spheroidal modes {sub 0}S{sub 21}-{sub 0}S{sub 34}, which are primarily sensitive to the structure of the transition zone. The apparent complex frequencies have then been inverted into local frequency and attenuation maps using the new inversion method. The authors have obtained consistent degree-2 patterns in the local attenuation maps as well as in the local frequency maps. The high-attenuation anomalies correlate with regions of slow P-wave velocity in the lower mantle and with regions of high hotspot density. This may represent a continuation of lower-mantle upwelling into the transition zone.
Assessing flood hazard on dynamic rivers

Recurrent flooding of the Red River in 1997, North Carolina's Tar River in 1999, and the Mississippi River in 1993, 1995, and 2001 has led to speculation that human activities contribute significantly to these disasters. New analyses of historical hydrologic data from the Mississippi River quantify systematic increases in flood stages for equal discharges. Analyses of cross-sectional measurements and other evidence suggest that rising stages result from flow retardation by navigational dikes and floodwater confinement by levees. On dynamic rivers, flood-frequency statistics must be revised periodically for hazard assessments to keep pace with current conditions, but the present reassessment methodology is prohibitively time-consuming and expensive.
Influences of climate, cattle density, and lake morphology on Sporormiella abundances in modern lake sediments in the US Great Plains

Sporormiella, a genus of coprophilous fungus, is increasingly used as a qualitative proxy for megafaunal density. Decreased spore abundances in Late-Pleistocene and Holocene sediments are thought to signal prehistoric megafaunal population declines and extinctions. However, much remains unknown regarding the dispersal, deposition, and preservation of Sporormiella, hindering interpretation. Here we collected lake-center and lake-margin surface-sediment samples from 24 lakes in a west–east transect across South Dakota, Minnesota, and Wisconsin to test whether Sporormiella abundances varied along a precipitation gradient and areas of varying grazing intensity. Unlike other pollen types, relative abundances and concentrations of Sporormiella spores were uncorrelated between lake-center and lake-margin samples. For lake-margin samples, distance-to-shoreline and county-scale cattle density were significant predictors of Sporormiella relative abundances. Only distance to shoreline was a significant predictor of Sporormiella concentrations. The positive relationship between shoreline proximity and Sporormiella abundances differs from prior reports that Sporormiella concentrations decrease away from shoreline. For lake-center samples, Sporormiella relative abundances were negatively correlated with precipitation and Sporormiella concentrations had no significant predictors. These results suggest that Sporormiella representation in lake sediments is controlled by multiple factors, including but not limited to local megaherbivore density. Sporormiella concentrations appear to be ‘noisier’ than Sporormiella relative abundances, due to within-basin sedimentary effects on pollen and spore accumulation rates. More work on Sporormiella taphonomy is critically needed to better understand the controls on its representation in late-Quaternary sediments.
Experimental observation of stick‐slip instability fronts

SUMMARY Stick-slip dynamic instability is a key mechanism governing frictional processes from microscale physics to earthquake faults and landslides; yet challenging questions are still open about its nucleation and propagation dynamics. Here we present novel observations on laboratory experimental faults where spontaneously nucleating fractures are produced, describing (1) an initial quasistatic, stable rupture front (propagating at about 5 per cent the shear wave velocity VS), accelerating to subshear and then to intersonic velocity; (2) the arisal of a higher degree of complexity when the friction to prestress ratio is increased on the sliding surface. The complex behaviour includes stop and go sequences, irregular propagation and rerupturing episodes within short-time intervals, implying rapid restrengthening of the surface and the formation of self-healing pulses, reproducing experimentally for the first time a behaviour observed on seismic faults.
The seasonal variation of the mixed layer and the pycnocline under polar sea ice

A model of the seasonal variation of the mixed layer and the pycnocline under polar sea ice is compared with observations during the Arctic Ice Dynamics Joint Experiment (AIDJEX) 1975–1976. The model is of the Kraus-Turner type, extended to include mixed layer and pycnocline. The forcing mechanisms are the mechanical mixing due to ice keel stirring and the surface buoyancy flux due to melting and freezing of sea ice. The model is designed to be used for climate studies in conjunction with atmospheric and oceanic general circulation models and with sea ice models.
Hodograph analysis of mesopause region winds observed by three MF radars in the Canadian Prairies

A new method of hodograph analysis is introduced and applied to studies of long period wind oscillations (2 to 10-hour period) in the upper mesosphere. observed by a triangle of medium frequency radars (500 km spacing) in the Canadian Prairies. This is compared with a method of spatial Fourier analysis which is also employed to study these oscillations. The results of these analyses are shown to be consistent with the behavior of atmospheric gravity waves: in particular, the gravity wave propagation directions are found to vary with season and with latitude. However, the directions do not seem to be consistent with blocking by the mean wind field, probably due to the gravity waves having phase velocities much higher than typical mean winds.
Developing Terrestrial-LIDAR-Based Digital Elevation Models for Monitoring Beach Nourishment Performance

Abstract Since the completion of a 398,000 m3 nourishment project along 2 km of Rehoboth Beach, Delaware, in August 2005, the subaerial volume and area of the northern 25% of the beach has been monitored monthly through the use of terrestrial-based light detection and ranging (LIDAR) surveys. Traditionally, the Delaware Department of Natural Resources and Environmental Control and the U.S. Army Corps of Engineers use analyses of beach width from aerial imagery and volumes estimated from widely spaced profile surveys to assess nourishment performance and assist in determining renourishment quantities. However, these survey methods lack the spatial and temporal resolution needed for short-term management strategies. Recent efforts at monitoring Atlantic Coast beaches using airborne LIDAR show the potential of this technology for providing more detailed representations of beach volumetric change over time, but the operational costs still limit the frequency of surveys. Alternatively, our terrestrial LIDAR study allows for the development of models of subaerial beach topography with both high temporal and spatial resolution. Although geographically less extensive than airborne surveys, the digital elevation models from our data (1) allow for a better understanding of the range in variation in beach area and volume, especially that due to storm events, (2) provide more accurate volume estimates than traditional profile surveys by as much as 8%, and (3) indicate that the area and volume do not covary, limiting the usefulness of using aerial imagery in estimating volume.
Using cosmogenic beryllium–7 as a tracer in sediment budget investigations

Recent advances in the use of the environmental radionuclides caesium–137 and unsupported lead–210 to quantify medium– and longer–term rates of erosion and sediment accumulation have proved of considerable value in catchment sediment budget investigations. However, there remains a need to explore the potential for using other shorter–lived radionuclides to provide evidence of sediment mobilisation, transport and storage over shorter timescales and particularly for individual events. This contribution reports the results of a study aimed at exploring the potential for using beryllium–7 (7Be, t½= 53.3 days) to meet this requirement. The study investigated the use of 7Be as a sediment tracer in three key components of the sediment budget, namely, soil erosion and sediment mobilisation from slopes, the transport, storage and remobilisation of fine sediment in river channels and overbank deposition on river floodplains. The results presented clearly demonstrate the potential for using 7Be to obtain information on short–term and event–based sediment redistribution rates for use in catchment sediment budget investigations.
Evaluation of satellite rainfall products through hydrologic simulation in a fully distributed hydrologic model

The goal of this study is to evaluate the accuracy of four global high‐resolution satellite rainfall products (CMORPH, TMPA 3B42RT, TMPA 3B42, and PERSIANN) through the hydrologic simulation of a 1656 km2 mountainous watershed in the fully distributed MIKE SHE hydrologic model. This study shows that there are significant biases in the satellite rainfall estimates and large variations in rainfall amounts, leading to large variations in hydrologic simulations. The rainfall algorithms that use primarily microwave data (CMORPH and TMPA 3B42RT) show consistent and better performance in streamflow simulation (bias in the order of −53% to −3%, Nash‐Sutcliffe efficiency (NSE) from 0.34 to 0.65); the rainfall algorithm that uses primarily infrared data (PERSIANN) shows lower performance (bias from −82% to −3%, Nash‐Sutcliffe efficiency from −0.39 to 0.43); and the rainfall algorithm that merges the satellite data with rain gage data (TMPA 3B42) shows inconsistencies and the lowest performance (bias from −86% to 0.43%, Nash‐Sutcliffe efficiency from −0.50 to 0.27). A dilemma between calibrating the hydrologic model with rain gage data and calibrating it with the corresponding satellite rainfall data is presented. Calibrating the model with corresponding satellite rainfall data increases the performance of satellite streamflow simulation compared to the model calibrated with rain gage data, but decreases the performance of satellite evapotranspiration simulation.
BEHAVIOUR OF THE CENTRES OF ACTION ABOVE THE ATLANTIC SINCE 1881. PART II: ASSOCIATIONS WITH REGIONAL CLIMATE ANOMALIES

This paper constitutes the second part of the analysis of the behaviour of centres of action above the Atlantic since 1881. The present study examines the applicability of the generated time series of the central pressure and geographical location of the Iceland Low (IL), Azores High (AH), Inter Tropical Convergence Zone (ITCZ) and South Atlantic Subtropical High (SSH) to the description of the surface circulation and its influence on the climate anomalies above the Atlantic and adjacent land areas in the period 1950—1989. Using the normalized anomalies of the pressure gradient between the cores of the AH and IL (AH—IL gradient) as a NAG (North Atlantic Oscillation) index, it can be shown that t his index is a practicable tool for the detection of characteristic spatial anomaly patterns in different climate variables above the North Atlantic and surrounding land areas. The ‘strong’ NAG (the AH-IL gradient above ‘normal’) in winter leads to a warming above northern and central Europe as well as to the development of the dipole-like anomaly patterns in the wind speed, sea-surface temperature, surface and tropospheric temperature and other variables above the western and eastern North Atlantic. The composite analysis for the ‘weak’ NAG reveals inverse patterns. The application of the characteristic parameters of the ITCZ and of the two subtropical highs as predictors of the rainfall variability in northeast Brazil and the Sahel for the period 1950-1983 shows that for the most part, these variations can be explained by the anomalies of the latitude position and intensity of the ITCZ. © 1998 Royal Meteorological Society. Int. J. Climatol. , 18, 23-36 (1998) No. of Figures: 3. No. of Tables: 5. No. of References: 71.
The Stability of the Oxford Clay as a Mineral Liner for Landfill

The paper discusses the mineralogical and chemical stability of the Oxford Clay as a landfill liner for the containment of domestic waste. The results from a series of batch equilibrium experiments with the mudrock and a synthetic leachate are compared with samples of a liner cored from a 15‐year‐old site in the Formation. The effects of leachate on the Clay include mineral dissolution, exchange of cations, particle‐size reduction and collapse of illite‐smectite. In situ mixed‐assemblage mineral liners, such as the Oxford Clay, are capable of attenuating leachate components and buffering acid leachates whilst the predominant clay minerals, i.e. illite and kaolinite, remain stable. Alterations to the mineralogy and chemistry of the samples resulting from both short‐term and long‐term exposure to leachate are discussed with reference to the implications to landfill practice.
Resistance to Overland Flow on Desert Pavement and Its Implications for Sediment Transport Modeling

Seventy-three overland flow experiments were performed on eight runoff plots located on a gentle piedmont hillslope in Walnut Gulch Experimental Watershed, southern Arizona. These plots were sited on gravel-covered desert pavement surfaces where overland flow occurs during natural rainstorms. Multiple regression analyses indicate that the Darcy-Weisbach friction factor ƒƒ can be well predicted by the Reynolds number and gravel concentration and size, with gravel concentration being by far the single best predictor. Grain resistance ƒƒ', calculated using Savat's algorithm, is found to be typically less than 10% of ƒƒ. Given that sediment transport capacity is controlled by grain shear stress τ' rather than total shear stress τ and that the ratio of τ' to τ is the same as that of ƒƒ to ƒƒ, sediment transport modeling on the gravel-covered hillslope under study must be based on τ' rather than τ to avoid gross overestimation of transport capacity. This conclusion is relevant to all gravel-covered desert hillslopes and probably also to most humid hillslopes and agricultural lands where plant stems, litter, and tilled surfaces replace gravel as sources of form resistance and ensure that grain resistance remains relatively small.
A Circulatory Loop: The Reciprocal Relationship of Organizations, Digitalization, and Gender

In the digitalization debate, gender biases in digital technologies play a significant role because of their potential for social exclusion and inequality. It is therefore remarkable that organizations as drivers of digitalization and as places for social integration have been widely overlooked so far. Simultaneously, gender biases and digitalization have structurally immanent connections to organizations. Therefore, a look at the reciprocal relationship between organizations, digitalization, and gender is needed. The article provides answers to the question of whether and how organizations (re)produce, reinforce, or diminish gender‐specific inequalities during their digital transformations. On the one hand, gender inequalities emerge when organizations use post‐bureaucratic concepts through digitalization. On the other hand, gender inequalities are reproduced when organizations either program or implement digital technologies and fail to establish control structures that prevent gender biases. This article shows that digitalization can act as a catalyst for inequality‐producing mechanisms, but also has the potential to mitigate inequalities. We argue that organizations must be considered when discussing the potential of exclusion through digitalization.
Analytic Determination of Hydrocarbon Transmissivity from Baildown Tests

Hydrocarbon baildown tests involve the rapid removal of floating hydrocarbon from an observation or production well, followed by monitoring the rate of recovery of both the oil/air and oil/water interfaces. This test has been used erroneously for several years to calculate the “true thickness” of hydrocarbon in the adjacent formation. More recent analysis of hydrocarbon distribution by Farr et al. (1990), Lenhard and Parker (1990), Huntley et al. (1994), and others have shown that, under vertical equilibrium conditions, there is no thickness exaggeration of hydrocarbon in a monitoring well, though there is a significant volume exaggeration. This body of work can be used to demonstrate that the calculation of a “true hydrocarbon thickness” using a baildown test has no basis in theory. The same body of work, however, also demonstrates that hydrocarbon saturations are typically much less than one, and are often below 0.5. Because the relative permeability decreases as hydrocarbon saturation decreases, the effective conductivity and mobility of the hydrocarbon is much less than that of water, even ignoring the effects of increased viscosity and decreased density.
The effect of soil type, meteorological forcing and slope gradient on the simulation of internal erosion processes at the local scale

Numerical simulation experiments of water erosion at the local scale (20 × 5 m) using a process‐based model [Plot Soil Erosion Model_2D (PSEM_2D)] were carried out to test the effects of various environmental factors (soil type, meteorological forcing and slope gradient) on the runoff and erosion response and to determine the dominant processes that control the sediment yield at various slope lengths. The selected environmental factors corresponded to conditions for which the model had been fully tested beforehand. The use of a Green and Ampt model for infiltration explained the dominant role played by rainfall intensity in the runoff response. Sediment yield at the outlet of the simulated area was correlated positively with rainfall intensity and slope gradient, but was less sensitive to soil type. The relationship between sediment yield (soil loss per unit area) and slope length was greatly influenced by all environmental factors, but there was a general tendency towards higher sediment yield when the slope was longer. Contribution of rainfall erosion to gross erosion was dominant for all surfaces with slope lengths ranging from 4 to 20 m. The highest sediment yields corresponded to cases where flow erosion was activated. An increase in slope gradient resulted in flow detachment starting upstream. Sediment exported at the outlet of the simulated area came predominantly from the zone located near the outlet. The microrelief helped in the development of a rill network that controlled both the ratio between rainfall and flow erosion and the relationship between sediment yield and slope length. Copyright © 2010 John Wiley & Sons, Ltd.
Projection of Global Wave Climate Change toward the End of the Twenty-First Century

AbstractWind-generated waves at the sea surface are of outstanding importance for both their practical relevance in many aspects, such as coastal erosion, protection, or safety of navigation, and for their scientific relevance in modifying fluxes at the air–sea interface. So far, long-term changes in ocean wave climate have been studied mostly from a regional perspective with global dynamical studies emerging only recently. Here a global wave climate study is presented, in which a global wave model [Wave Ocean Model (WAM)] is driven by atmospheric forcing from a global climate model (ECHAM5) for present-day and potential future climate conditions represented by the Intergovernmental Panel for Climate Change (IPCC) A1B emission scenario. It is found that changes in mean and extreme wave climate toward the end of the twenty-first century are small to moderate, with the largest signals being a poleward shift in the annual mean and extreme significant wave heights in the midlatitudes of both hemispheres, more.
Hydrodynamic Efficiency of a New Design of Half-Submerged Breakwater Compared to a Rectangular Caisson

In this paper, the wave transmission, reflection, and energy dissipation characteristics as well as the hydrodynamic forces of two partially submerged breakwaters are compared. The breakwaters under consideration are designed to be installed in coastal areas where the water depth may be important (typically 50 m), making traditional bottom seated configurations unsuitable. They are composed of a free-surface piercing caisson mounted on vertical piles. The first breakwater considered in this study, as a matter of reference for comparison, is a rectangular caisson. The second one is a new profile proposed by Colmard and called BYBOP by the writer. The seaside face, fronting the ocean, is an elliptic profile while the harbor side is a plane inclined 55° to the vertical. A numerical simulation on both these shapes, at model scale, was carried out in two numerical wave tanks. The first one, CANAL, is based on fully nonlinear potential flow theory while the second one, ICARE, is a Reynolds averaged Navier–Stoke.
Three-dimensional crustal structure of the Mariana island arc from seismic tomography

[1] A three-dimensional (3-D) seismic refraction survey was acquired over the Mariana volcanic arc at 14.5–18.5N and 145–147E. First-arrival traveltimes from this survey and from a separate 2-D survey acquired approximately perpendicular to the arc have been simultaneously inverted for a 3-D P wave velocity model using seismic tomography subject to smoothness constraints. The active arc, which initiated only 3–4 Ma ago, has an average crustal thickness of 18 km. Approximately 40 km to the east the inactive remnant of the rifted Eocene arc has an average crustal thickness of 21 km, due primarily to a thicker lower-crustal layer with velocities of 6.5–7.0 km s � 1 . Crustal production clearly varies both temporally and spatially, with some crustal layers, including the igneous forearc crust, varying in thickness by a factor of up to 2 along strike. Average P wave velocities within the upper crust of the modern arc are 240–360 m s � 1 lower than in the Eocene arc but are 280 m s � 1 higher within the lower crust. Middle crust with velocities of 6.0–6.5 km s � 1 is best developed beneath the Eocene arc. These results suggest an evolution of arc structure with increasing age: We infer closure of fractures and porosity in the upper crust through hydrothermal circulation and a reduction in the mafic character of the middle to lower crust as a result of intracrustal differentiation. Although tonalitic rocks may predominate in the transition from upper to middle crust, the bulk of the crust is essentially basaltic.