Miracle-dz/UniFAR-FTUs huggingface dataset:
Spatial and diurnal variability in reactive nitrogen oxide chemistry as reflected in the isotopic composition of atmospheric nitrate: Results from the CalNex 2010 field study

Here we present measurements of the size‐resolved concentration and isotopic composition of atmospheric nitrate (NO3−) collected during a cruise in coastal California. Significant differences in air mass origin and atmospheric chemistry were observed in the two main regions of this cruise (South and Central Coast) with corresponding differences in NO3− concentration and isotope ratios. Measurements of the 17O‐excess (Δ17O) of NO3− suggest that nocturnal chemistry played an important role in terms of total NO3− production (~ 50%) in the coastal Los Angeles region (South Coast), where NO3− concentrations were elevated due to the influence of sea breeze / land breeze recirculation and Δ17O(NO3−) averaged (25.3 ± 1.6)‰. Conversely, Δ17O(NO3−) averaged (22.3 ± 1.8)‰ in the Central Coast region, suggesting that the daytime OH + NO2 reaction was responsible for 60–85% of NO3− production in the marine air sampled in this area. A strong diurnal signal was observed for both the Δ17O and δ15N of NO3−. In the case of Δ17O, this trend is interpreted quantitatively in terms of the relative proportions of daytime and nighttime production and the atmospheric lifetime of NO3−. For δ15N, which had an average value of (0.0 ± 3.2)‰, the observed diurnality suggests a combined effect of isotopic exchange between gas‐phase precursors and variability in reactive nitrogen sources. These findings represent a significant advance in our understanding of the isotope dynamics of nitrate and its precursor molecules, with potentially important implications for air quality modeling.
Inequality of Opportunities in the Educational Attainment of Chilean Students

This study measures the contribution of inequality of opportunities on the educational attainment of Chilean students, captured through the SIMCE test scores. For this, it employs a recently introduced methodology that quantifies the effect of exogenous and endogenous factors on socioeconomic outcomes, using parametric and non-parametric techniques. The study applies this methodology for the SIMCE tests in Mathematics and Language in the 1999 to 2007 period for fourth grade primary, eighth grade primary and for second grade of secondary school. The results show a reduction in the percentage of inequality of SIMCE results arising from exogenous circumstances, which can be interpreted as a decrease in inequality of opportunities. This conclusion is robust to the estimation technique and the schooling grade. In addition, the results reveal that inequality of opportunities is greater in secondary school than in primary school.
Comparison of mean climate trends in the northern hemisphere between National Centers for Environmen

A hole is formed in soil by penetrating it with a tool comprising a shaft having a tapered point or auger of relatively small cross section attached to its lower end, and a series of outwardly pressing rams mounted on the shaft above the tapered point. The rams are effective successively to enlarge incrementally by outward compaction or displacement of the soil, the hole initially formed by the tapered point or auger. Full hole dimension above the tool is maintained by reason of the fact that the soil is incrementally compacted and compressed to resist collapse. If desired, the integrity of the hole may be preserved with the aid of a following shield, or the hole may be filled with soil stabilizing fluid such as drilling mud. After formation of the hole, the tool is withdrawn and the hole may be filled with concrete to form a load supporting column or it may be left as an open shaft. The method and apparatus may also be used to enlarge the diameter of an existing hole.
Randomized sampling and sparsity: Getting more information from fewer samples

Many seismic exploration techniques rely on the collection of massive data volumes that are subsequently mined for information during processing. Although this approach has been extremely successful in the past, current efforts toward higher-resolution images in increasingly complicated regions of the earth continue to reveal fundamental shortcomings in our workflows. Chiefly among these is the so-called “curse of dimensionality” exemplified by Nyquist’s sampling criterion, which disproportionately strains current acquisition and processing systems as the size and desired resolution of our survey areas continue to increase. We offer an alternative sampling method leveraging recent insights from compressive sensing toward seismic acquisition and processing for data that are traditionally considered to be undersampled. The main outcome of this approach is a new technology where acquisition and processing related costs are no longer determined by overly stringent sampling criteria, such asNyquist. At the hea.
Clay Deposits for Water Management of Sandy Soils

Water management practices in conserving water for arid lands are crucial in sustaining agriculture and food production. Sandy soils (Typic Torrripsamments) are practically important land resources in many Middle Eastern countries. In a laboratory experiment, five naturally occurring clay deposits were applied at different rates to sandy calcareous soil in order to evaluate their effect on relative swelling, infiltration and water conservation. Relative swelling index (RSI), cumulative infiltration (D), and advance of wetting front (Z) were measured in the laboratory for untreated and treated soil samples mixed with 1, 2, 3, and 5% of the clay deposits. Results indicated that addition of natural deposits significantly increased RSI. The differences in RSI values between natural deposits at any rate of application were significant and related to clay content and presence of smectite type clay. RSI values for each clay deposit fitted to the following exponential function with the application rate x (RSI = aebx). Results of D indicated that increasing natural deposit rate significantly increased the time required for the wetting front to reach 40 cm. There was a significant difference between the clay deposits at 5% rate and the difference was related to the type of clay and clay content in each deposit. The presence of CaCO3, dominance of kaolinite type clay and low clay content in the deposits enhanced water movement while dominance of smectite clay and high clay content decreased D. Advance of wetting front was markedly affected by the type and the rates of clay deposit applied. Z decreased with increasing rates of clay deposits. Soil water distribution profile was characterized by three zones based on the type and the rate of applied clay deposit to the soil.
Transverse ion energization and wave emissions observed by the Freja satellite

Observations by the Freja satellite at altitudes of about 1700 km in the auroral zone sometimes show energization of both light and heavy ions to characteristic energies of up to about 50–100 eV. This ion heating is often associated with lower hybrid waves, and also with wave emissions at lower frequencies. No obvious decrease of electric field wave power below the proton gyrofrequency, reported by other spacecraft at similar altitudes, is observed in the regions of intense ion heating. Furthermore, localized density depletions associated with lower hybrid waves have not been detected in these regions. We present a preliminary model where waves observed during an event in the evening-side auroral zone are used to explain the observed ion energies.
Vegetation composition, gradients and environment relationships of birch forest in six reference areas in Norway

Vegetation composition, gradients and environment relationships of birch forest in six reference areas in Norway Terrestrial Monitoring of boreal birch forest ecosystems (TOV) was initiated in 1989 by the Directorate for Nature Management. The programme has a multidisciplinary approach and integrates studies of precipitation, soil water, soil, understorey vegetation composition, lichens on birch trunks, population studies of birds and mammals and environmental pollutants in plants and animals. Here we present studies of forest floor vegetation at establishment, which supplements and complements two studies established in boreal coniferous forests in 1988: ‘The effect of acid precipitation on forest and forest understorey vegetation in Gjerstad, South Norway’ and ‘Vegetational and environmental monitoring of boreal spruce forest in ten reference areas’, the latter initiated by the Norwegian Institute of Land Inventory (NIJOS) as part of a forest health monitoring programme. The reference areas were selected to span regional gradients in climatic conditions and deposition of airborne pollutants, in old-growth bilberry-dominated birch forest in Norway. Ten macro plots in each reference area were located to span differences in nutrient and soil moisture conditions, terrain features, etc. by a sampling design similar to the one used in coniferous forests. Fifty 1×1 m meso sample plots, randomly chosen within the ten macro plots, were subjected to vegetation analysis, using frequency in subplots as well as percent cover as species abundance measures. The main vegetational gradients were found by parallel use of DCA and GNMDS ordination methods; the results of which were subjected to environmental interpretation by means of non-parametric correlation and split-plot GLM analyses. Both ordination methods gave to large degree similar, interpretable, vegetation gradients. The most important ecoclines were related to variation in nutrient conditions, best expressed by pH, Ca, K and S. Tree influence, topographic (un)favourability, soil moisture and soil depth were other factors which were correlated with one of the two main vegetation gradients (ecoclines). The main vegetational gradients and environmental/climatic/geographical complex gradients in the total data set were found by DCA and subsequent interpretation of the axes. The main complex gradient corresponded to the variation in the vegetation from sites with low pH and low content of nutrients (low concentrations of macro nutrients like C, Ca, Mn, S and Total N) and high loss on ignition to vice versa. The second gradient corresponded to variation in the vegetation from sites with high effective temperature sums at low latitudes and high soil concentrations of Mn and S, to sites with opposite characteristics. Most of the variation (> 80%) in the vegetation compositions could be ascribed to the between macro plots scale level, leaving a small residual variation on the between area and in the plots within macro plot scale level.
Possible Juventae Chasma subice volcanic eruptions and Maja Valles ice outburst floods on Mars: Implications of Mars Global Surveyor crater densities, geomorphology, and topography

[1] This article discusses image, topographic, and spectral data from the Mars Global Surveyor (MGS) mission that provide new information concerning the surface age, geomorphology, and topography of the Juventae Chasma/Maja Valles system. Our study utilizes data from two instruments on board MGS: images from the Mars Orbiter Camera (MOC) and topography from the Mars Orbiter Laser Altimeter (MOLA). Within Maja Valles we can now observe depositional bars with megaripples that unequivocally show catastrophic floods occurred in the channel. Viking impact crater densities indicated the chasma and channel floor areas were all one age (late Hesperian to Amazonian); however, MOC data indicate a marked difference in densities of small craters between Juventae Chasma, Maja Valles, and the channel debouchment area in Chryse Planitia basin. Although other processes may contribute to crater variability, young resurfacing events in the chasma and episodes of recent erosion at Maja Valles channel head may possibly account for the disparate crater densities along the chasma/channel system. Relatively young volcanic eruptions may have contributed to resurfacing; as in Juventae Chasma, a small possible volcanic cone of young dark material is observed. MOC data also indicate previously unknown interior layered deposit mounds in the chasma that indicate at least two periods of mound formation. Finally, MOLA topography shows that the entire floor of the chasma lies at the same elevation as the channel debouchment area in Chryse basin, resulting in a 3-km-high barrier to water flow out of the chasma. Blocked ponded water would rapidly freeze in the current (and likely past) climate of Mars. For catastrophic flow to occur in Maja Valles, some process is required to melt ice and induce floods out of the chasma. We suggest subice volcanic eruption and calculate estimates of water discharges and volumes that these eruptions might have produced.
Hydraulic jumps in sloping channels : Sequent depth ratio

A large variety of hydraulic jumps on horizontal and sloping inverts at the end of an ogee standard weir is investigated. An ogee standard weir was used to create supercritical flow and slopes of 0.0, −0.025 , −0.05 , −0.075 , and −0.10 were built downstream of the weir. Based on the momentum equation in the horizontal direction, a method to predict the sequent depth ratio is presented. The theory agrees well with the results of the writers and previous investigators. A correlation was developed to predict the minimum Froude number needed to establish jumps on negative slopes. Observations showed that in those cases where the gravity force component in the jump was opposite to the flow direction, the water surface of the surface roller became undular and unstable. The hydraulic jump on an entirely adverse slope was almost impossible to control. The analysis of experimental data showed that the negative slope of the basin reduces the sequent depth ratio, while a positive slope increases the sequent depth r.
The impact of ambient stratification on freshwater transport in a river plume

The purpose of this study is to delineate the influence of stratified ambient water on river plume structure and freshwater transport in the plume. The Regional Ocean Modeling System (ROMS) is applied to conduct a parameter study, where the inflow salinity anomaly, ambient stratification and the bottom slope are varied systematically. Ambient water is thermally stratified. Temperature is set uniform in the top 15 m layer and then decreases linearly, while in the non-stratified case temperature remains constant at its surface value. The results show that in all non-stratified cases an anticyclonic bulge at the mouth and a parallel coastal current further downstream form. On the other hand, under stratified conditions, an inflow with a lower salinity anomaly causes the formation of a frontal disturbance at an earlier stage downstream of the plume bulge, with more eddies developing later in time along the density front. These eddies grow rapidly in both offshore and downstream directions and move with the downstream current. In extreme cases, they spread 100 km offshore by the end of the model run (60 days), which is triple the offshore extension in non-stratified cases. Under the same fresh water input, more eddies develop either when the inflow salinity anomaly is smaller or when the stratification is stronger. Eddies form later, grow at a slower rate and are less developed offshore with a gentler slope. All the eddy forming plumes are bottom advected plumes. Under stratified conditions the density front detaches from the bottom at a shallower depth but spreads further offshore at the surface. Reconstructed alongshore velocities based on geostrophic balance prove that the different distributions of isopycnals cause differences in alongshore velocity fields. Higher salinity anomaly inflows form surface advected plumes which perform similarly to non-stratified cases, without eddy formation. Freshwater fluxes are calculated in both downstream and offshore directions to quantify the difference between stratified and non-stratified cases under low salinity anomaly conditions. The rapid growth of eddies traps a large amount of freshwater which substantially (up to 35%) reduces the downstream freshwater flux compared to the non-stratified case. As eddies pass through the fixed transect, the downstream freshwater flux fluctuates up to 30% of a corresponding value in the non-stratified case. The offshore freshwater flux estimated 30 km from the coast is several times higher due to the presence of frontal eddies when compared with corresponding non-stratified case. Energy transfer diagnostics indicate that frontal eddies are likely to be produced through the barotropic instability of the buoyancy-driven current.
Lower Viruan discontinuity surfaces in central Sweden

Abstract Near the base of the Viru Series (Middle Ordovician) in Vastergotland, south-central Sweden, discontinuity surfaces in the limestones mark breaks in sedimentation. The morphology of these surfaces has been studied in Hallekis Quarry at Kinnekulle and Gullhogen Quarry at Billingen, with particular emphasis on lateral variations. Four main morphological types of discontinuity surface are distinguished. One has furrows arranged in a polygonal pattern which may represent mudcracks. The basal Viruan discontinuity surface in Gullh[obar]gen Quarry shows laminated structures resembling stromatolites. At H[abar]llekis, the basal Viruan discontinuity surface has sac-shaped cavities up to 10 cm deep, produced by boring organisms. At Billingen, the amount of boring by hard-bottom endofauna was low and the discontinuity surfaces were mostly associated with high energy conditions, as indicated by conglomerates, blankets of oolites, and erosional phenomena. Stromatolites and mudcracks suggest shallow water cond.
Twenty Years of Progress with SDI in Kansas.

This paper will summarize research efforts with subsurface drip irrigation in Kansas that have occurred during the period 1989 through 2009. Special emphasis will be made on brief summaries of the different types of research that have been conducted including water and nutrient management for the principal crops of the region, SDI design parameters and system longevity and economics. Annual system performance evaluations have shown that dripline flowrates are within 5% of their original values. Economic analysis shows that systems with such longevity can be cost competitive even for the lower-valued commodity crops grown in the region.
GloFAS – global ensemble streamflow forecasting and flood early warning

Abstract. Anticipation and preparedness for large-scale flood events have a key role in mitigating their impact and optimizing the strategic planning of water resources. Although several developed countries have well-established systems for river monitoring and flood early warning, figures of populations affected every year by floods in developing countries are unsettling. This paper presents the Global Flood Awareness System (GloFAS), which has been set up to provide an overview on upcoming floods in large world river basins. GloFAS is based on distributed hydrological simulation of numerical ensemble weather predictions with global coverage. Streamflow forecasts are compared statistically to climatological simulations to detect probabilistic exceedance of warning thresholds. In this article, the system setup is described, together with an evaluation of its performance over a two-year test period and a qualitative analysis of a case study for the Pakistan flood, in summer 2010. It is shown that hazardous events in large river basins can be skilfully detected with a forecast horizon of up to 1 month. In addition, results suggest that an accurate simulation of initial model conditions and an improved parameterization of the hydrological model are key components to reproduce accurately the streamflow variability in the many different runoff regimes of the earth.
Development of rainfall warning thresholds for debris flows in the Honolulu District, Oahu

The goal of this investigation is to determine threshold levels of intensity and duration of storm rainfall necessary to initiate debris flows on the steep hillslopes of the Honolulu District. These rainfall thresholds could find a future application in a debris-flow warning system for Honolulu, similar to a prototype warning system developed several years ago and now operating in the San Francisco Bay region in northern California. Previous studies suggest that debris flows are triggered when heavy rainfall, infiltrating into the shallow subsurface, becomes impounded and creates elevated pore pressures that weaken the slope materials. Based on this idea, a simple numerical model was developed to study the interaction between heavy rainfall and pore-pressures on steep hillslopes. In order to calibrate this model to the ground conditions within the Honolulu District, detailed recordings of both rainfall and shallow pore pressures have been made at two remote sites on steep hillslopes. These recordings confirm the presence of temporarily elevated pore pressures in response to heavy rainfall and show a correlation between the peak porepressure response and the maximum amounts of rainfall recorded for periods of 3 to 6 hours. An extensive historical data base of rainfall amounts and debris flow occurrences has been compiled for 17 large storms in the Honolulu District over the past 33 years. Plots of these historical data display well defined, lower bound relationships between the number of debris flows reported during storms and the peak rainfalls recorded over periods of 1 to 6 hours. Two threshold levels were derived from these lower bound relations: a "safety" threshold below which the likelihood of damaging debris flows is very low, and an "abundant" threshold level above which rainfall is likely to cause many debris flows and thus pose a hazard to life and property.
Simulating the Regional Impacts of Urbanization and Anthropogenic Heat Release on Climate across China

AbstractTogether with economic development and accelerated urbanization, the urban population in China has been increasing rapidly, and anthropogenic heat released by large-scale energy consumption in cities is expected to be a vital factor affecting the climate. In this paper, the Weather Research and Forecasting (WRF) model coupled with the Urban Canopy Model (UCM) is employed to simulate the regional impacts on climate under the two scenarios: the underlying surface changes due to urbanization (USCU) and anthropogenic heat release (AHR). Three experiments were performed from December 2006 to December 2008. With respect to the USCU, the surface albedo and the available surface soil water decrease markedly. With the inclusion of AHR, the two scenarios give rise to increased surface temperatures over most areas of China. Especially in the urban agglomeration area of the Yangtze River delta, the combination of USCU and AHR could result in an increase of 2°C in the surface air temperature. The influence of .
Repeatability enhancement in deep‐water permanent seismic installations: a dynamic correction for seawater velocity variations

With the increasing use of permanently installed seismic installations, many of the issues in time‐lapse seismic caused by the lack of repeatability can be reduced. However, a number of parameters still influence the degree of reliability of 4D seismic data. In this paper, the specific impact of seawater velocity variations on time‐lapse repeatability is investigated in a synthetic study. A zero‐lag time‐lapse seabed experiment with no change in the subsurface but with velocity changes in the water column is simulated. The velocity model in the water column is constant for the baseline survey while the model for the repeat survey is heterogeneous, designed from sea salinity and temperature measurements in the West of Shetlands. The difference section shows up to 80% of residual amplitude, which highlights the poor repeatability. A new dynamic correction which removes the effect of seawater velocity variations specifically for permanent installations is developed. When applied to the synthetic data, it reduces the difference residual amplitude to about 3%. This technique shows substantial improvement in repeatability beyond conventional time‐lapse cross‐equalization.