Miracle-dz/UniFAR-FTUs huggingface dataset:
I.—The Physiographic Significance of Laterite in Western Australia

During the last six or seven years a series of valuable papers bearing on the origin of laterite has appeared in the Geological Magazine. The conclusions arrived at have been somewhat diverse and contradictory. Dr. Fermor, on the one hand, regarded the laterites of India as residual in character, and believed that they represented the insoluble residues left in the process of rock weathering after the soluble constituents had been removed in solution. Mr. Simpson, at the other extreme, suggested that they represented the soluble material, leached out of the subjacent rocks during weathering under peculiar conditions, and deposited as a chemically-formed rock by precipitation at the surface of the earth.
Inter-comparison of radiometric calibration of Terra and Aqua MODIS 11-μm and 12-μm bands

Currently there are two Moderate Resolution Imaging Spectroradiometer (MODIS) instruments operating on-orbit, one on-board the NASA Earth Observing System (EOS) Terra spacecraft launched in December 1999 and the other on the EOS Aqua spacecraft launched in May 2002. Since its launch, each MODIS has been making continuous observations and producing calibrated data sets for the studies of the state of the Earth system and the changes of the global environment. MODIS 11 m and 12 m bands are primarily used for measuring the land and sea surface temperatures. These two bands have higher calibration accuracy requirements of 0.5% at specified typical radiance than most other thermal emissive bands (TEBs) of 1%. All the MODIS TEBs are calibrated on-orbit by an on-board calibrator blackbody (BB). To examine and verify the calibration consistency between Terra and Aqua MODIS in the thermal emissive bands, we have performed inter-comparison of MODIS 11 m and 12 m bands using closely matched thermal infrared (TIR) channels of the Advanced Very High Resolution Radiometer (AVHRR) onboard the NOAA-16 and NOAA-17. Our previous investigations only used the AVHRR LAC (local area coverage) data sets that have very limited availability. In this paper, we present our analysis of comparing the results from using LAC data sets and that from using the GAC (global area coverage) data sets. The use of GAC data sets provides more opportunities for the long-term trending analysis. Our results from August 2002 to July 2004 show that the measured temperature of Terra MODIS at 11 m and 12 m are about 0.20K higher than that from the Aqua MODIS at a brightness temperature range of 250 to 280K. Using the MODIS as an intermediate transfer reference, the results indicate that the 11 m and 12 m channels of the AVHRR on NOAA-16 are about 0.3K and 0.4K warmer than that on NOAA-17 in the same temperature range.
The Suspension Of Sand By Waves

Measurements are presented of the concentrations of sediment near rippled beds of sand in an oscillatory flow water tunnel. The measurements were made using a lightabsorption type of probe. The sediment was observed to be entrained from the bed in two ways. Firstly, bed-load carried over the crest is hurled in an, initially, thin jet over the lee vortex. Secondly, the vortex ejected at the end of each half cycle throws up a plume of sediment into the flow. The measurements were compared with results for bed-load transport over flat beds and also with predictions based on the defect-velocity distribution for rough beds.
Active deformation of Asia : From kinematics to dynamics

Using estimated strain rates across the actively deforming region of Asia to infer variations in viscous stress, it is shown that gradients of stress point uphill toward the center of Tibet, where gravitational potential energy per unit surface area reaches a maximum. Thus, the dynamics of the deformation seem to obey the equation of creeping flow, which expresses a balance between gradients in stress and the gravitational body force. This balance, in the region of the Tibetan plateau, yields an estimate of 10 22 pascal second for the average viscosity of the Tibetan lithosphere, which is only about 10 to 100 times greater than the viscosity of the convecting upper mantle.
Electromagnetic prospecting for groundwater in Precambrian terrains in the Republic of Upper Volta

The “Autorite des amenegements des valees des Voltas (AVV)” is establishing new rural settlements in the Volta valleys. First, a survey of available water supplies is performed. Economic aquifers in Precambrian terrains are deep (15–50 m) and usually occur in fractured zones accompanying faults. Such zones can be identified on aerial photographs, but their precise location on the ground is virtually impossible by visual means. Because of the small size of the aquifers, a location error of 5 m can make the difference between a productive well and a dry hole. Traditionally, resistivity profiling has been used as the means of locating the fractured zones in the field. Our studies suggest that the task can be performed faster, cheaper and more accurately by VLF and EM methods. Because of the limited choice of transmitting stations reccivable in Upper Volta, the VLF method is not sufficiently sensitive to detect conductors with a strike between 45° and 105°. The results obtained with a multifrequency, horizontal-loop EM (HLEM) system were satisfactory in all investigated areas. During the 1980 field season, 35 target areas were surveyed. Of the 24 holes drilled so far, 23 are productive. The weathered layer is a source of distinctive HLEM anomalies, which are characteristic of the underlying rocks. Therefore, different interpretational procedures had to be developed for granitic and volcano-sedimentary areas. Despite the high background level of in-phase and quadrature components, which varied with thickness and conductivity of the weathered layer, aquifers could be detected at a depth greater than 30 m. Attempts were made to interpret the HLEM results quantitatively using two models: a three-layer medium and a valley discontinuity. The latter model is more realistic, but more scale modelling will have to be performed to permit development of viable interpretational procedures. Meanwhile, phasor diagrams based on drilling and resistivity sounding data can be used to estimate the aquifer depth.
UPPER BOUND PLASTICITY ANALYSIS OF A PARTIALLY-EMBEDDED PIPE UNDER COMBINED VERTICAL AND HORIZONTAL LOADING

Seabed pipelines undergo temperature cycles that create axial load which can be relieved through controlled lateral buckling. The prediction of lateral buckling in design requires accurate assessment of the lateral breakout resistance. This Technical Note describes upper bound plasticity analysis of a partially-embedded pipe on undrained soil. The purpose is to generate failure envelopes for vertical and horizontal loading to provide a theoretical basis for estimating breakout resistance. The following cases have been considered: smooth and rough pipes, with and without separation at the rear face of the pipe. The envelopes are similar to those developed previously for surface foundations, but capture additional effects that are due to the curved geometry of the pipe surface. The breakout resistance and the movement of the pipe at failure are strongly influenced by the separation condition. Pipe roughness and soil self-weight have a relatively minor effect on breakout resistance. Existing empirical expressions usually assume a linear variation in breakout resistance with embedment and vertical load. This theoretical analysis demonstrates that these relationships are non-linear. The resulting envelopes provide a more rigorous basis for predicting the breakout resistance of partially-embedded pipelines.
Does Anything Beat 5-Minute RV? A Comparison of Realized Measures Across Multiple Asset Classes

We study the accuracy of a wide variety of estimators of asset price variation constructed from high-frequency data (so-called "realized measures"), and compare them with a simple "realized variance" (RV) estimator. In total, we consider almost 400 different estimators, applied to 11 years of data on 31 different financial assets spanning five asset classes, including equities, equity indices, exchange rates and interest rates. We apply data-based ranking methods to the realized measures and to forecasts based on these measures. When 5-minute RV is taken as the benchmark realized measure, we find little evidence that it is outperformed by any of the other measures. When using inference methods that do not require specifying a benchmark, we find some evidence that more sophisticated realized measures significantly outperform 5-minute RV. In forecasting applications, we find that a low frequency "truncated" RV outperforms most other realized measures. Overall, we conclude that it is difficult to significantly beat 5-minute RV.
Aerosol optical depth of the atmosphere over the ocean in the wavelength range 0.37–4 µm

At least two problems, the climatic impact of aerosols and improvement in techniques for space‐borne sensing, require investigation of the spatiotemporal variability of the aerosol optical depth (AOD) over the ocean. The marine atmosphere covers an area 2.5 times greater than the continental atmosphere and has essential differences in the composition and manner of aerosol variability, but the quantity of available data is significantly less. Hence, the importance of measurements of the aerosol optical characteristics in marine expeditions is clear. This paper generalizes the results of investigations of the AOD of the atmosphere carried out in the past decade onboard Russian scientific vessels in different regions of the Atlantic Ocean. Statistical characteristics of the AOD are presented for typical regions of the Northern Atlantic: near midlatitude continents, open ocean, tropical and equatorial zones. We show that aerosol turbidity in the atmosphere of the southern hemisphere decreases with latitude, and the minimum values are observed near Antarctica. The results of ship‐borne measurements of the AOD of the atmosphere are compared with the data from several island stations of the global Aerosol Robotic Network (AERONET). The spectral behaviour of the AOD in the visible and near‐infrared wavelength range (0.37–4 µm) is considered. The Ångström exponent is used for analysis of the wavelength dependence in the shortwave range, and the mean value of the AOD in four ‘atmospheric transparency windows’ from 1.2 µm to 4 µm is used in the longwave range. Special attention is paid to revealing the dependence of the AOD on relative humidity, wind velocity in the near‐water layer and the synoptic factor, the change in air mass.
Impact of regulated releases on periphyton and macroinvertebrate communities: The dynamic relationship between hydrology and geomorphology in frequently flooded rivers.

Flood‐type disturbances affect both periphyton and macroinvertebrate communities depending on their frequency, magnitude and duration, but some impacts can be mitigated by geomorphic constraints. We studied four rivers in the Adirondack Mountains; the Indian River experienced regulated flow releases creating bank‐full floods four times/week whereas other study sites provided a continuum of control conditions for comparison. We sampled periphyton and macroinvertebrate communities in each river along with channel hydrology, hydraulics and geomorphology. Periphyton abundance varied seasonally and among rivers depending on nitrate concentrations and scour. Flow releases created a static mosaic of patches consisting of heavily scoured bed sediment in the thalweg (high shear stress areas—HSS) which had very low periphyton abundance; boulders and rocky shoals created low shear stress areas (LSS) supporting mats of filamentous algae. Macroinvertebrate densities were highest in HSS areas whereas LSS areas had lower macroinvertebrate densities that were more similar to reference rivers, although both LSS and HSS areas had the lowest species diversity and richness. Macroinvertebrate composition in HSS areas was dominated by filter‐feeders, whereas LSS areas had more gatherers and scrapers. While all rivers had high boulder densities, the Indian River could be considered geomorphically moribund—its substrate was immobile and the channel experienced no adjustments in spite of high flood frequencies. These physical characteristics help mitigate the severe hydrologic conditions that releases create because the static mosaic of low and HSS patches allow certain macroinvertebrates adapted to this level of disturbance to persist. This static mosaic is different from the shifting mosaic pattern often observed in streams following flood‐type disturbances. Geomorphically moribund rivers may lack ecological sensitivity to hydrologic disturbances, and decisions to limit flow modification (e.g. recreational flow releases, hydropower generation) should consider whether assumed ecological impacts are likely to occur given local geomorphic conditions and constraints. Copyright © 2010 John Wiley & Sons, Ltd.
Exhumation of the Dabie Shan ultra-high-pressure rocks and accumulation of the Songpan-Ganzi flysch sequence, central China

The presence of coesite- and diamond-bearing ultra-high-pressure (UHP) metamorphic rocks in the Dabie and Sulu regions, central China, suggests that a >100-km-thick crustal section (4 x 106 km6 in volume) has been denuded. This volume is comparable to that represented by the 10-15-km-thick Middle to Upper Triassic flysch rocks in the Songpan-Ganzi region. Regional geology and radiometric dates are compatible with an interpretation that the majority of these sedimentary rocks were derived from denudation of the orogenic belt between North and South China blocks following their latest Paleozoic to Triassic collision. This correlation implies a high denudation rate of ∼4 mm/yr that may have been in part promoted by tropical precipitation and extreme topographic relief for as long as 25 m.y.
Understanding fossilization: Experimental pyritization of plants

The process of fossilization is poorly understood. However, it is central to our understanding of the evolution of life. It is unclear how plant tissues become fossilized, whether fossilization is selective to specific biopolymers, or whether original organic constituents survive. We have replicated the fossilization process in the laboratory by using both microbial and chemical approaches to pyritize plant debris. These results demonstrate that initial pyritization can be an extremely rapid process (within 80 days) and is driven by anaerobic bacterial-mediated decay. Initially, pyrite precipitates on and within plant cell walls and in the spaces between them. Further decay and infilling at all scales preserves broad cellular anatomy. The results have implications for fossilization in general and the fidelity of the taxonomic and biomolecular information preserved in fossils.
Crustal and upper mantle seismic structure beneath the rift mountains and across a nontransform offset at the Mid-Atlantic Ridge (35°N)

We present new results on the crustal and upper mantle structure beneath the rift mountains along two segments of the Mid-Atlantic Ridge and across a nontransform offset (NTO). Our results were obtained from a combination of forward modeling and two-dimensional tomographic inversion of wide-angle seismic refraction data and gravity modeling. The study area includes two segments: OH-1 between the Oceanographer fracture zone and the NTO-1 at 34°35′N and OH-2 between NTO-1 and the NTO at 34°10′N. The center of OH-1 is characterized by anomalously thick crust (∼8 km) with a thick Moho transition zone with Vp = 7.2–7.6 km/s. This transition zone, coincident with a gravity low, is probably composed of gabbro sills alternating with dunites, as observed in some ophiolites. OH-1 has larger along-axis crustal thickness variations than OH-2, but average crustal thicknesses are similar (6.0±1.2 km at OH-1, 6.1±0.7 at OH-2). Thus we do not find significant differences in magma supply between these segments, in contrast to what has been inferred from morphological and gravity studies. At both segments the shoaling of the Moho is more rapid at the inside than at the outside corners, consistent with models in which the inside-corner crust is technically modified. The structural differences between inside- and outside-corner crust are more apparent at OH-2, suggesting that the extrusive layer is thinner at the inside corner of OH-2 than at the inside corner of OH-1, probably due to differences in axial morphology and along-axis magma transport. NTO-1 is characterized by a nearly constant velocity gradient within the upper 5 km and low upper mantle velocities (7.4–7.8 km/s). The anomalous structure beneath NTO-1 is interpreted as fractured mafic crust. The P wave velocities and densities required to match the gravity data suggest that serpentinites are common beneath the NTO-1 and possibly beneath the inside corners. Serpentinization could be as much as 40% at ∼3.8 km below seafloor and probably does not occur at subseafloor depths greater than ∼6.2 km at the NTO-1. Our results indicate that in a slow spreading environment where magmatism and tectonism are equally important, the seismic Moho cannot be correlated with an unique geological structure. At the center of a segment the seismic Moho may represent the lower boundary of an interlayered grabbro-dunite transition zone, while beneath the inside corner and NTO where the crust is thinner, it may correspond to an alteration front.
Precipitation predictors for downscaling: observed and general circulation model relationships

Because of the coarse resolution of general circulation models (GCM), ‘downscaling’ techniques have emerged as a means of relating meso-scale atmospheric variables to grid- and sub-grid-scale surface variables. This study investigates these relationships. As a precursor, inter-variable correlations were investigated within a suite of 15 potential downscaling predictor variables on a daily time-scale for six regions in the conterminous USA, and observed correlations were compared with those based on the HadCM2 coupled ocean/atmosphere GCM. A comparison was then made of observed and model correlations between daily precipitation occurrence (a time series of zeroes and ones) and wet-day amounts and the 15 predictors. These two analyses provided new insights into model performance and provide results that are central to the choice of predictor variables in downscaling of daily precipitation. Also determined were the spatial character of relationships between observed daily precipitation and both mean sea-level pressure (mslp) and atmospheric moisture and daily precipitation for selected regions. The question of whether the same relationships are replicated by HadCM2 was also examined. This allowed the assessment of the spatial consistency of key predictor–predictand relationships in observed and HadCM2 data. Finally, the temporal stability of these relationships in the GCM was examined. Little difference between results for 1980–1999 and 2080–2099 was observed. For correlations between predictor variables, observed and model results were generally similar, providing strong evidence of the overall physical realism of the model. For correlations with precipitation, the results are less satisfactory. For example, model precipitation is more strongly dependent on surface divergence and specific humidity than observed precipitation, while the latter has a stronger link to 500 hPa divergence than is evident in the model. These results suggest possible deficiencies in the model precipitation process, and may indicate that the model overestimates future changes in precipitation. Correlation field patterns for mslp versus precipitation are remarkably similar for observed data and HadCM2 output. Differences in the correlation fields for specific humidity are more noticeable, especially in summer. In many cases, maximum correlations between precipitation and mslp occurred away from the grid box; whereas correlations with specific humidity were largest when the data were propinquitous. This suggests that the choice of predictor variable and the corresponding predictor domain, in terms of location and spatial extent, are critical factors affecting the realism and stability of downscaled precipitation scenarios. Copyright © 2000 Royal Meteorological Society
Seasonal and latitudinal variations of the electron density nonmigrating tidal spectrum in the topside ionospheric F region as resolved from CHAMP observations

In this study we present for the first time the nonmigrating tidal spectrum for the electron density in the topside ionosphere on global scale for different seasons at both solar maximum and minimum conditions. The electron density observations from the CHAMP (CHAllenging Minisatellite Payload) satellite provide evidence for prominent nonmigrating tides at different latitude regions. At middle and high latitudes the most prominent diurnal tides are DE1, D0, and DW2, as well as semidiurnal tides SW1 and SW3 preferably during equinox seasons. DE1 is only found in the northern middle and high latitudes, while D0 and DW2 are much stronger in the Southern Hemisphere. These tides are believed to be driven by the thermospheric winds through ion‐neutral interactions. At equatorial and low‐latitude regions the most prominent diurnal tides are DE2 and DE3. DE2 is found to be present at low‐latitude regions throughout the whole year with larger amplitudes in the Southern Hemisphere, while DE3 shows largest amplitudes (symmetric above the dip equator) at the equatorial ionization anomaly (EIA) crest region during September equinox. A general antiphase behavior between the EIA crest and trough is observed for the tides DE3, DE2, DW2, and SW3. We consider this as strong evidence for the modulation of the EIA electron density by the E layer zonal electric field via the ion fountain effect. An exception is the tidal component D0, which exhibits antiphase variations between the two hemispheres. The phase value at the equatorial trough is halfway between those of the two hemispheres. Presently, we cannot give an explanation for it, and study concerning special model effort is further needed.
Water Balance Components in a Mature Citrus Orchard

The low water-holding capacity of sandy soils, together with spatial and temporal variations of rainfall, require Florida citrus trees to be irrigated for optimal production. Citrus tree root systems are exposed to various hydrologic conditions because of soil temperature and water gradients due to tree canopy shading and under-tree microirrigation. The main goal of this study was to evaluate water balance components in a mature citrus orchard grown on central Florida ridge soils with special interest in quantifying rainfall interception by a citrus canopy and its effect on effective rainfall estimation. Soil water content was monitored every 30 min at 10-, 20-, 40-, and 80-cm depths in the root zone both under and outside of citrus tree canopies. Microirrigation, rainfall, and weather data were used to calculate effective rainfall, plant water uptake, and deep drainage. We found that the tree canopy intercepted 35 and 50% of the incoming high (≥5-mm) and low (<5-mm) intensity rainfalls, respectively. Effective rainfall calculated without accounting for the canopy interception effect was overestimated by about 30 and 5% for the dry and wet periods, respectively. Citrus crop evapotranspiration was higher under the tree canopy (irrigated area) than outside the tree canopy (unirrigated area) during the dry season because of supplemental irrigation.