Miracle-dz/UniFAR-FTUs huggingface dataset:
Measurement of waterdrop impact pressures on soil surfaces

Limited data on pressures induced by waterdrop impact on soil surfaces restricts our understanding the mechanism of soil detachment due to raindrop impact. Impact pressures on rigid surfaces are known but their application to soil surfaces is questionable. This study was undertaken to measure vertical pressures of waterdrop impact on soil surfaces. A 1-mm diam piezoelectric transducer was developed and measurements of impact pressures as a function of radial distance from drop center were made. Dickinson loam (coarse-laomy, mixed, mesic Typic Hapludoll) and Ida silt loam (fine-silty, mixed [calcareous] mesic Typic Udorthent) with bulk densities of 1.0 and 1.2 Mg/m3 and with matric potentials of -0.5 and -2.5 kPa were used. The waterdrop had a diameter of 5.6 mm and a fall height of 14 m. Average peak impact pressures were greatest at a distance of 1.8 to 2.3 mm from center of impact and of the order of 190 to 290 kPa. These stress levels are almost two orders of magnitude less than those for impact on a rigid surface. Much of the difference between soil and rigid cases was due to nonrigid, nonhomogenous nature of the soil material. The remainder of the difference in stress levels was thought to be due to the effect of soil granularity or to the presence of surface and shear waves generated by impact.
Larval fish abundance, composition and distribution at Senghor Seamount (Cape Verde Islands)

The Cape Verdean Senghor-Seamount rises up to 93 m below the surface, and lies within the Cape Verde Frontal Zone (CVFZ), and within the southwestward North Equatorial Current. The seamount and its oceanic surroundings were surveyed with Multiple-Opening-Closing Net (MCN) fish larval catches, Issacs-Kidd midwater trawl (IKMT) micronekton hauls and an analysis of some conductivity–temperature–depth data (RV Poseidon cruise no. POS 320/2). The thermal and saline stratifications showed widely symmetrical uplifts near the summit. The larval fish community was diverse (H′ = 2.656) and composed mainly of larvae of meso- to bathypelagic species (91.5%). In IKMT, 44.1% of the specimens originated from demersal parents (H′ = 3.296), and mostly, albeit not entirely, from West African coastal waters, after advection along the CVFZ to and across this potential “stepping stone”. Gross larval fish abundance (median 35.5 specimens/1 m2) and composition agreed well with historical literature data from adjacent waters and seamounts north of the CVFZ, whereas south of the CVFZ and towards NW-Africa reported abundances were higher. Vertical distributions of larvae which generally live at greater depths showed a rise above the seamount, following the hydrographic uplift, accompanied by “thinning-out effects” through bathymetric disturbance. The extent to which findings at Senghor Seamount are representative for small, shallow and steep seamounts in the tropical NE-Atlantic is discussed.
Numerical simulations of a light nonaqueous phase liquid (LNAPL) movement in variably saturated soils with capillary hysteresis

The fate and transport of pollutants in the subsurface is usually predicted using numerical simulations. Comparisons of the simulation results with experimental data are required to validate the numerical codes. In this paper, the nonaqueous phase liquid (NAPL) simulator code was used to numerically simulate two centrifugal light nonaqueous phase liquid (LNAPL) transport experiments. The numerical predictions were compared with the centrifugal test results and the impact of capillary hysteresis was evaluated. It was concluded that the simulation with the nonhysteretic model slightly underestimated the LNAPL volume retained in the vadose zone, and the average error of the predicted LNAPL saturation in the vadose zone and along the plume centerline was approximately 5% to 10%. The application of capillary hysteresis for the numerical simulation of the second centrifuge test has eliminated this error. In addition, accounting for hysteresis in the numerical simulation of the second centrifuge test has conside.
Pāhoehoe flow cooling, discharge, and coverage rates from thermal image chronometry

Theoretically‐ and empirically‐derived cooling rates for active pāhoehoe lava flows show that surface cooling is controlled by conductive heat loss through a crust that is thickening with the square root of time. The model is based on a linear relationship that links log(time) with surface cooling. This predictable cooling behavior can be used assess the age of recently emplaced sheet flows from their surface temperatures. Using a single thermal image, or image mosaic, this allows quantification of the variation in areal coverage rates and lava discharge rates over 48 hour periods prior to image capture. For pāhoehoe sheet flow at Kīlauea (Hawai`i) this gives coverage rates of 1–5 m2/min at discharge rates of 0.01–0.05 m3/s, increasing to ∼40 m2/min at 0.4–0.5 m3/s. Our thermal chronometry approach represents a quick and easy method of tracking flow advance over a three‐day period using a single, thermal snap‐shot.
An aggregation‐disaggregation approach to long‐term reservoir management

The problem is to find the monthly operating policy of Hydro‐Québec's 26 large reservoirs that maximizes the utility's expected profits over a period of several years. The problem is solved in a hierarchical way. First, the optimal operating policy of the whole system, represented by an aggregate model, is found by stochastic dynamic programming (SDP). This gives not only the hydroelectric energy to produce in a month but also, as is very important in a deregulated market, the expected marginal value of the hydroelectric energy produced. At the second level the expected marginal value of the potential energy stored in each river is determined by solving a SDP problem with two state variables: one for the energy content of the river and the other for the energy content of all the other rivers combined. These marginal values are used afterward to divide the hydroelectric production among the rivers. At the third level the production assigned to each river is distributed between the reservoirs so as to minimize the spillages first, and then the square of the deviations of the reservoir levels from the target level. The targets are adjusted to maximize the expected long‐term production of the river. The monthly inflows to the reservoirs are the only random variables in this problem.
Storm‐time penetration to low latitudes of magnetospheric‐ionospheric convection and convection‐driven thermospheric winds

From DE‐2 satellite measurements during two magnetic storms, we show that (i) the magnetospheric convection‐driven east‐west ion flows of high velocities (1400 m/s) penetrate to magnetic latitudes as low as 30°, with larger velocities (2000–3000 m/s) appearing at 45°–50° latitudes, and (ii) high velocity (300–640 m/s) thermospheric winds appear in association with the above ion flows. The similarity of the latitude structures and time evolutions of the ion and neutral motions indicates that the zonal winds are driven by magnetospheric‐ionospheric convection through ion drag. These velocities of the convection‐driven ion flows and winds at such low latitudes are much larger than those reported from observations or predicted by current models.
Effect of stair-step and piecewise linear topography on internal wave propagation in a geophysical flow model

[1] The paper describes the effect of a stair-step representation of bottom topography, common in most numerical models, on the propagation of internal waves in a geophysical flow. An analytical solution was used to predict the effect of stair-step and piecewise linear representations of topography on the reflection and transmission of internal waves. The Estuary Lake and Coastal Model (ELCOM) was used to simulate the transmission of a train of small-amplitude internal gravity waves propagated along a variable depth rectangular channel containing a linearly stratified fluid. The effect of the different obstacle approximations was examined in terms of the interference of the resulting wave number content, and hence the associated reflection coefficients, which could be directly compared to the analytical theory. It was shown that for Gaussian obstacles of varying lengths and heights, the full bottom cells and partial bottom cells solutions from ELCOM agree with the stair-step and piecewise linear solutions from the theory, respectively. It was shown that when Gaussian obstacles with weak slopes are represented by stair steps, an aliasing that is similar to that in discrete Fourier transform can occur, resulting in reflection coefficients that are much higher than the exact solution. On the other hand, piecewise linear approximations produce significantly attenuated aliasing. An immersed boundary technique that enforces a no-flux condition at the actual sloping bottom, similar to that of the analytical solution, is found not to produce better numerical results.
Dynamic and static recrystallization-related microstructures in halite samples from the Kłodawa salt wall (central Poland) as revealed by gamma-irradiation

Microstructures of 33 rocksalt specimens from gallery walls from the highly strained part of the K odawa Salt Structure (Poland) were analyzed in gamma-irradiated and etched thin sections in reflected and transmitted light. Two types of microstructures could be distinguished i) dynamic recrystallization related ones caused by natural deformation and ii) static recrystallization related ones with uncertain origin, perhaps caused by subsequent mine-wall convergence. Natural deformation-related microstructural features are the abundant subgrains and strain-free regions at grain boundaries together with elongated subgrains which imply dislocation climb controlled creep accompanied with fluid-assisted grain boundary migration as the deformation mechanism. Using subgrain size piezometry, differential stresses between 0.9 to 3.1 MPa were calculated. All the samples contain a few percent (< 5 %) of euhedral statically recrystallized phase. In three samples the euhedral, statically recrystallized grains may comprise up to 85 % of the material. The microstructure suggests that the static recrystallization post-date the natural deformation-related features. The static recrystallization is thought to be due to mine-wall convergence. The pervasive crack system in the samples may also be explained by the stress concentration and subsequent minor mine-wall convergence. Detailed observations of the mutual relationship between the microcracks and the euhedral, statically recrystallized phase imply that as the new grains have grown, and
Sediment fluxes and buffering in the post‐glacial Indus Basin

The Indus drainage has experienced major variations in climate since the Last Glacial Maximum (LGM) that have affected the volumes and compositions of the sediment reaching the ocean since that time. We here present a comprehensive first‐order source‐to‐sink budget spanning the time since the LGM. We show that buffering of sediment in the floodplain accounts for ca. 20–25% of the mass flux. Sedimentation rates have varied greatly and must have been on average three times the recent, predamming rates. Much of the sediment was released by incision of fluvial terraces constructed behind landslide dams within the mountains, and especially along the major river valleys. New bedrock erosion is estimated to supply around 45% of the sedimentation. Around 50% of deposited sediment lies under the southern floodplains, with 50% offshore in large shelf clinoforms. Provenance indicators show a change of erosional focus during the Early Holocene, but no change in the Mid–Late Holocene because of further reworking from the floodplains. While suspended loads travel rapidly from source‐to‐sink, zircon grains in the bedload show travel times of 7–14 kyr. The largest lag times are anticipated in the Indus submarine fan where sedimentation lags erosion by at least 10 kyr.
Trends in high flows in the central Spanish Pyrenees: response to climatic factors or to land-use change?

Abstract This paper analyses the evolution of high flows in the central Spanish Pyrenees during the period 1955–1995. The method applied makes it possible to assess whether the contribution of the largest daily discharge and rainfall events to the total annual runoff and precipitation remains stationary or shows any temporal trend. The results show a general negative trend in flood intensity in the last decades, together with an increase in the importance of low flows in the total annual contribution. However, a change in the frequency distribution of precipitation events has not been detected. The different behaviour shown by runoff and precipitation could only be explained as being due to the increase in vegetation cover that is a consequence of the farmland abandonment and reforestation that occurred during the 20th century.
Phosphorus Cycling in Unfertilized and Fertilized Agricultural Soils

Surface soil samples (0–50 mm depth) were taken from several grassed and cropped, unfertilized and P-fertilized soils at monthly intervals for 2 yr, to investigate seasonal variations in amounts and forms of P and relative importance of inorganic and organic P as sources of plant available P. Although no consistent seasonal variation in inorganic P content was observed for the unfertilized soils, amounts increased after fertilizer P addition. Organic P content was higher in the winter (Oct.–Mar.) than spring months (May–June) for both unfertilized and fertilized soils. Consequently, mineralization of organic P during the growing season, which contributed similar amounts of P (20–74 kg P ha) as added in fertilizer (13–100 kgP ha), was not inhibited by fertilizer P addition. Organic P variation was mainly due to changes in moderately labile organic P, with more labile and resistant pools remaining constant. The most labile organic P pool was maintained at a constant level possibly by mineralization and formation from moderately labile organic P. Little change in P content of unfertilized subsurface soil (50–150 mm) was observed, although inorganic and available P contents increased slightly following fertilizer P application. Available P (Bray-I P) was closely correlated with organic P in unfertilized soils and with inorganic P in fertilized soils. Slopes of these relationships were related to phosphatase enzyme activity and P sorption maximum for organic and inorganic P, respectively. The importance of organic P as a source of available P in both unfertilized and fertilized soils was demonstrated. The need to include organic P in soil-P fertility tests, especially with the increasing use of reduced-tillage practices, is emphasized.
Changing patterns of heavy rainfall in upland areas: a case study from northern England

There has recently been a widespread shift in the pattern of UK rainfall towards more heavy falls of rain in winter and fewer in summer. Here, this change is examined in the context of orographic enhancement for a transect of rain gauges running across northern England from coast to coast and including both the Lake District and Pennine uplands. Gauges have been selected where very long records of daily rainfall exist; where data are missing, these have been infilled using data from nearby gauges. The very long records for Armagh and Durham are also included to provide additional context in time and space. For the upland gauges, the increase in total winter rainfall in recent decades and the simultaneous decrease in total summer rainfall are reflected in the number of heavy falls of rain, as defined using two threshold indices. The 1990s saw record numbers of heavy falls in winter and an almost complete absence of heavy summer rainfall in the uplands, in marked contrast to lowland gauges. Comparison of the rainfall record with the Lamb Weather Catalogue suggests that increased winter rainfall is related to an increase in the rainfall provided by westerly weather types. Decreased summer rainfall is related to a reduction in rainfall associated with cyclonic weather types. The results presented here underline the value of long‐term monitoring and the maintenance of records from key historic sites. Copyright © 2010 Royal Meteorological Society
On post-glacial sea level: I. General theory

SUMMARY Modern analyses of sea level changes due to glacial isostatic adjustment (GIA) are based on the classic sea level equation derived by Farrell & Clark (1976, Geophys. J.R. astr. Soc., 46, 647–667). The connection between global sea level variations and changes to ocean height that is assumed within this equation breaks down in the presence of a time-varying shoreline geometry. We present a generalized sea level equation that overcomes this difficulty. We also derive analytic expressions for, and present schematic illustrations of, the error in the ocean height change over finite time intervals introduced in published efforts to incorporate shoreline evolution into the theory of GIA-induced sea level change. This comparison includes studies of shoreline migration due to either local sea level changes or the growth and ablation of marine-based ice. We conclude that the theories applied by Johnston (1993, Geophys. J. Int., 114, 615–634), Milne (1998, PhD thesis, University of Toronto, Toronto) and co-workers are more accurate than the procedure advocated by Peltier (1994, Science, 265, 195–201; 1998a, Geophys. Res. Lett., 25, 3955–3958; 1998b, Rev. Geophys., 114, 615–634), although an improvement in the latter has recently been reported (Peltier & Drummond (2002, Geophys. Res. Lett., 29, 10.1029/2001GL014273). Our generalized theory is valid for any Earth model. In a companion paper we derive the equations necessary to treat the special case of a spherically symmetric, linear viscoelastic and rotating Earth, and we quantify errors associated with previous work.
Estimating uncertainty of the WMO mole fraction scale for carbon dioxide in air

[1] The current WMO CO2 Mole Fraction Scale consists of a set of 15 CO2-in-air primary standard calibration gases ranging in CO2 mole fraction from 250 to 520 μmol mol−1. Since the WMO CO2 Expert Group transferred responsibility for maintaining the WMO Scale from the Scripps Institution of Oceanography (SIO) to the Climate Monitoring and Diagnostics Laboratory (CMDL) in 1995, the 15 WMO primary standards have been calibrated, first at SIO and then at regular intervals, between 1 and 2 years, by the CMDL manometric system. The uncertainty of the 15 primary standards was estimated to be 0.069 μmol mol−1 (one-sigma) in the absolute sense. Manometric calibrations results indicate that there is no evidence of overall drift of the Primaries from 1996 to 2004. In order to lengthen the useful life of the Primary standards, CMDL has always transferred the scale via NDIR analyzers to the secondary standards. The uncertainties arising from the analyzer random error and the propagation error due to the uncertainty of the reference gas mole fraction are discussed. Precision of NDIR transfer calibrations was about 0.014 μmol mol−1 from 1979 to present. Propagation of the uncertainty was calculated theoretically. In the case of interpolation the propagation error was estimated to be between 0.06 and 0.07 μmol mol−1 when the Primaries were used as the reference gases via NDIR transfer calibrations. The CMDL secondary standard calibrations are transferred via NDIR analyzers to the working standards, which are used routinely for measuring atmospheric CO2 mole fraction in the WMO Global Atmosphere Watch monitoring program. The uncertainty of the working standards was estimated to be 0.071 μmol mol−1 in the one-sigma absolute scale. Consistency among the working standards is determined by the random errors of downward transfer calibrations at each level and is about 0.02 μmol mol−1. For comparison with an independent absolute scale, the five gravimetric standards from the National Institute for the Environmental Studies (NIES) in Tsukuba, Japan, ranging in CO2 mole fraction from 350 to 390 μmol mol−1 have been calibrated relative to the CMDL secondary standards. The average and standard deviation of the differences between the NIES gravimetric and CMDL analyzed CO2 mole fraction are 0.004 ± 0.03 μmol mol−1.
Detection of auroral activity using GPS satellites

GPS (Global Positioning System) satellites and a receiver located at Fairbanks, Alaska are used to detect auroral activity. A technique for using GPS total electron content (TEC) data to detect auroral-E ionization (AEI) at all satellite line-of-sight elevations is presented. The location of AEI during auroral substorms is determined and is consistent with simultaneous magnetometer data. Maps of detected AEI events reveal the distribution of AEI in space and time. Additionally, a technique is presented for identifying the effects of the auroral oval E-layer on the TEC data. Particle precipitation measured by the TIROS satellite is closely related to variations in the TEC data. The effects of the oval are consistently seen in the TEC data for a variety of magnetic conditions. The location of the equatorward edge of the oval is determined during auroral substorms and compares well with a model of the oval and with individual TIROS passes.
The basic intrusive rocks of Caledonian age of the Haddo House and Arnage districts, Aberdeenshire

Synopsis Basic igneous rocks of the Haddo House and Arnage districts consist of olivine-norites, and quartz-norites which include uralitised and xenolithic types. No layered sequence is observed in the basic igneous rocks of Haddo House and Arnage and their petrochemistry suggests that some water must have entered the magma in that area producing hypersthene- and quartz-normative rock types. This would account for the differences observed between the igneous rocks of Haddo and Arnage and those in other parts of north-east Scotland which were intruded at the same time, and might be products of the same parental magma.
M‐component currents of first return strokes in natural negative cloud‐to‐ground lightning

Records of M‐component currents of first return strokes in natural negative cloud‐to‐ground lightning measured in a short instrumented tower are shown along with correlated video records, electric field changes, and relative luminosity. The synchronized fast‐camera records clearly match the increase of luminosity of the faint lightning channel. The parameters of these M components are all consistent with those of triggered lightning. According to records of electric field change of lightning events near Morro do Cachimbo Station and of currents measured at the instrumented tower, the frequency of first return strokes exhibiting M components is within the range of tens of percent and not of a few percent, as usually accepted. This expectation of a few percent is based on a very low number of first return strokes expected to be followed by continuing currents. It was found that most of the analyzed first‐return‐stroke M components of natural lightning occur at the final phase of the return‐stroke process and not during the flow of continuing currents. Apparently, this also holds true for most of the first M components of subsequent return strokes.