Miracle-dz/UniFAR-FTUs huggingface dataset:
Snow-ice growth: a fresh-water flux inhibiting deep convection in the Weddell Sea, Antarctica

Abstract During a field experiment in July 1994, while the R.V. Nathaniel B. Palmer was moored to a drifting ice floe in the Weddell Sea, Antarctica, data were collected on sea-ice and snow characteristics. We report on the evolution of ice which grew in a newly opened lead. As expected with cold atmospheric conditions, congelation ice initially formed in the lead. Subsequent snow accumulation and large ocean heat fluxes resulted in melt at the base of the ice, and enhanced flooding of the snow on the ice surface. This flooded snow subsequently froze, and, 5 days after the lead opened, all the congelation ice had melted and 26 cm of snow ice had formed. We use measured sea-ice and snow salinities, thickness and oxygen isotope values of the newly formed lead ice to calculate the salt flux to the ocean. Although there was a salt flux to the ocean as the ice initially grew, we calculate a small net fresh-wlter input to the upper ocean by the end of the 5 day period. Similar processes of basal melt and surface snow-ice formation also occurred on the surrounding, thicker sea ice. Oceanographic studies in this region of the Weddell Sea have shown that salt rejection by sea-ice formation may enhance the ocean vertical thermohaline circulation and release heat from the deeper ocean to melt the ice cover. This type of deep convection is thought to initiate the Weddell polynya, which was observed only during the 1970s. Our results, which show that an ice cover can form with no salt input to the ocean, provide a mechanism which may help explain the more recent absence of the Weddell polynya.
Cavity and topographic effects in tilt and strain measurement

Cavities, surface topography, and inhomogeneities in elastic constants all distort the strains and tilts produced by stresses in the earth. Hence locally observed strains and tilts deviate from those calculated on the basis of simple earth models. We investigate these deviations on the assumption that the scale of these inhomogeneities is small in comparison with that of the stress fields. The results are applicable to observations of free modes, earth tides, and regional tectonic stresses. Analytical results are given for the deformation of an ellipsoidal cavity in a homogeneous medium in which the strain is uniform at large distances from the cavity. One important result is that greatly magnified strains are expected across narrow cavities. Finite element techniques are employed to study two features of importance in actual cavities, the influence of the corner in a tunnel of square cross section and the influence of the end face in a cylindrical tunnel with plane ends. The floor of the perfectly regular square tunnel remains flat, but irregularities produce large local tilts. Longitudinal strain in the cylindrical cavity is magnified near its ends, and most of the anomalous strain is concentrated within one tunnel diameter of the end. Topographic effects are also studied by finite element techniques. These are found to be very large and to result in strain magnifications in valleys, strain diminutions in hills, and strain-induced tilts which are different for vertical and horizontal surfaces. In one case, regional compression actually results in local tension, and even a 1 in 10 (5.7°) slope produces a 36% perturbation in strain. Geological effects are investigated for a profile near Boulder, Colorado, where there is a very abrupt transition between the sedimentary rocks of the plains and the basement rocks of the Front Range of the Rocky Mountains. The surface strains perpendicular to the boundary fall from 177% to 37% of their regional values on crossing this boundary, and strain-induced tilts attain values of about 0.5 times the regional strain in its vicinity. Long-base strain meters and tiltmeters can give good results in underground sites, but short-base instruments are very susceptible to local effects arising from geometric irregularities or rock inhomogeneities. Corrections for local topography are required for most installations. This topographic effect can be exploited to measure regional strains with tiltmeters, while the geological effects provide the basis of a technique for using earth tide observations to explore geological structure.
Algal Mats, Cryptalgal Fabrics, and Structures, Hamelin Pool, Western Australia

Cryptalgal sediments and structures in Hamelin Pool, Western Australia, are formed by interactions between blue-green algae, which trap and bind sediment particles, and a variety of mechanical and diagenetic processes. The algae form a cohesive mat that tends to cover intertidal, supratidal, and some shallow subtidal surfaces. The mat is differentiated into seven intergradational types as an expression of variations in algal species present, ratio of filamentous to unicellular forms, quantity of mucilaginous matrix, life habits, and quantity and nature of the host sediment. The distribution of mat types is controlled by environmental factors such as elevation of substrate, drainage, depth and nature of interstitial groundwater, and sediment influx. In tidal flats with gen le gradients, there is a broad zonation of mat types, whereas the mat is highly differentiated and has a condensed, patchy development of types on headlands and locations with irregular topography. The sediments trapped and/or bound by the algal-mat communities are imprinted with distinctive fabrics. These fabrics, which can be related to specific mat types, reflect a complex interaction between the algae and processes of sedimentation and diagenesis. Important factors in the development of fabric are surface texture and internal structure of the mat, rate and frequency of sediment influx, and processes such as oxidation, cementation, and lithification. Changes in mat type with changes in environmental conditions (e.g., shoaling and sediment influx) lead to the development of successions of fabrics in the sediment pile. The mat-sediment complex is shaped by physical factors into a variety of structures: (1) extensive flat-lying sheets, (2) ridge and rill structure, (3) rings and crescents, (4) linked ellipsoids and columns, (5) discrete ellipsoidal and circular columns, and (6) calyx and tiered calyx structures. The size range of structures varies from a few centimeters to several meters; confluent and branched structures also are common. The gross morphology of the structures is largely independent of the mat type (or types) involved in the primary trapping and/or binding processes. Major environmental factors involved in shaping of structures are waves, currents, substrate gradient, and long-term sea-level change; minor factors include burial, exhumation, growth of epiphytes, activity of browsing organisms, gas evolution, corrosion, precipitation, desiccation, and variation in sediment type. These factors also influence the external surface texture of structures.
An object-based SVM method incorporating optimal segmentation scale estimation using Bhattacharyya Distance for mapping salt cedar (Tamarisk spp.) with QuickBird imagery

Salt cedar, a predominant arid type of vegetation in Western China, provides invaluable ecosystem services and is important for economic sustainability. Most previous attempts to map salt cedar have been focused at the pixel level and not at the object level. A particular problem for object-based classification is determining the optimal scale for the segmentation. In this study, we proposed a new object-based image analysis method for classifying high resolution satellite image with support vector machine (SVM). Specifically, we set forth three objectives: (1) to choose the optimal multiscale parameters for different cover types with the aid of the Bhattacharyya Distance index; (2) to extract the class specific features for different classes to feed into the SVM classification procedure; and (3) to compare three different classification methods: the integration of object-SVM, SVM at the pixel level and nearest-neighbor at the object level. The result of the case study demonstrated that the multiscale object-SVM method, which employed spectral, texture and shadow features, produced the best overall accuracy (91.6%).
OPTIMIZATION OF VERTICAL DISTRIBUTION OF CANOPY NITROGEN : AN ALTERNATIVE TRAIT TO INCREASE YIELD POTENTIAL IN WINTER CEREALS

Summary This article reviews the literature on the relation between vertical leaf nitrogen distribution and canopy photosynthesis, as a possible route to maximize radiation use efficiency, biomass production and yield potential in winter cereals. Main assumptions underlying the prediction of the optimum vertical leaf nitrogen allocation, i.e., the role of light climate within the canopy and total leaf nitrogen content, are revised. Dynamic aspects and possible impact of manipulation of vertical leaf N distribution on yield and quality of winter cereals are discussed and areas for future research highlighted.
Mesozoic Stratigraphy of Central Honduras

Geologic mapping near Lake Yojoa in central Honduras has shown the need to modify the published Mesozoic stratigraphic column. The Ilama Formation is not a useful unit for regional mapping inasmuch as "Ilama-type" strata are discontinuous and in various stratigraphic positions. The formal name Ilama Formation should be abandoned. A new formal name, the Jaitique Formation, is introduced to designate a major Cenomanian limestone unit that is stratigraphically about midway in the Valle de Angeles Group in the Santa Barbara-Lake Yojoa region. The Jaitique Formation consists of up to 140 m of shallow-marine strata that can be divided into two members: (1) a lower member of thick-bedded shelf carbonate strata, and (2) a distinctive upper member of thin-bedded, laminated, nonfossiliferous limestone which may represent a shallow, possibly hypersaline, lagoon or intertidal mud-flat environment. Because the lower member of this Cenomanian limestone was formerly misidentified as the Atima Formation of the Yojoa Group, the upper, thin-bedded member was originally defined as the Guare Formation of the Yojoa Group. The name Guare is retained, but the unit is downgraded to the Guare Member of the newly defined Jaitique Formation within the Valle de Angeles Group. Although the Jaitique Formation is similar in stratigraphic position and age to the Esquias Formation in the Minas de Oro area on the east, it is lithologically distinct, and probably slightly older. The two units are not thought to be lithostratigraphically contiguous. Recognition of major Cenomanian limestone units within the Valle de Angeles Group has led to reappraisal of the hydrocarbon potential of certain structural zones in Honduras.
Wave Loadings Acting on an Innovative Breakwater for Energy Production

Vicinanza, D. , Ciardulli, F. , Buccino, M. , Calabrese, M. and Kofoed, J.P., 2011. Wave loadings acting on an innovative breakwater for energy production. Journal of Coastal Research, SI 64 (Proceedings of the 11th International Coastal Symposium), ��� – ���. Szczecin, Poland, ISSN 0749-0208 The paper reports on 2 D small scale experiments conducted to investigate wave loadings acting on a pilot project of device for the conversion of wave energy into electricity. The conversion concept is based on the overtopping principle and the structure is worldwide known with the acronym SSG. The hydraulic model tests have been carried out at the LInC laboratory of the University of Naples Federico II using random waves. Results indicate wave overtopping is able to cause a sudden inversion of vertical force under wave crest, so that it is alternatively upward and downward directed over a short time interval. It is also shown that two calculation methods widely employed in the Japanese design practice of vertical face breakwaters, namely Goda (1975) and Hiroi (1919), could be used to achieve safe estimates of the hydrodynamic loadings
High‐precision relative thermobarometry: theory and a worked example

A number of sources of uncertainty are involved in thermobarometric calculations, the most important of which are associated with analytical precision, activity–composition (a–x) relationships, and thermodynamic data. Statistical treatment of these uncertainties results in relatively large uncertainties on the calculated values of pressure and temperature. Little can be done, at least in the short term, about the magnitude of such uncertainties, and any thermobarometric calculations in which they are not taken into account should be treated with caution. Given that uncertainties associated with a–x models and thermodynamic data are systematic when applied to multiple samples with the same mineral assemblage, a solution to the problem of imprecise absolute thermobarometry can be obtained via a relative thermobarometric technique referred to as the ΔPT approach. The ΔPT approach offers a major improvement in the precision of thermobarometry if the calculations can be presented in a ΔPT context.
Experimental and Numerical Study on the Flow Field and Friction Factor in a Pressurized Corrugated Pipe

AbstractAn experimental campaign including measurement of pressure drops and velocity profiles was conducted on the pressurized flow in a commercial corrugated pipe. The results show that the empirical graphs suggested by Morris in the fifties may produce inaccurate assessments of the friction factor, in particular, for low Reynolds numbers. The experimental data was then reproduced by means of a numerical model with the large eddy simulation (LES) technique. The friction factor behavior for low and relatively high Reynolds numbers was thus investigated. The numerical simulations were in good agreement with the experimental results, showing the LES suitability to predict the effect of the pipe wall corrugation on the mean flow in a range of Reynolds numbers typical of engineering applications. To provide a quantitative evaluation of the numerical model, the Nash–Sutcliffe model efficiency coefficient E and the root mean square error (RMSE) were calculated, demonstrating the goodness of the numerical resul.
A palaeoenvironmental record of natural and human change from the Auckland Isthmus, New Zealand, during the late Holocene

Abstract A multi‐proxy analysis of a sediment core from Waiatarua, Auckland Isthmus, adds to an environmental history from the local wetland spanning the Late Glacial to modern times. Several distal tephra were recorded in the core: 8.5 ka Rotoma (reworked), 6.1 ka Tuhua (primary and reworked), most likely the 1.8 ka Taupo (the latter is previously unreported for the Auckland Isthmus), and one unidentified, possibly 665 yr BP Kaharoa. Pollen and diatom analyses of the core show that during the period c. 6000‐c. 4800 yr BP, the site was a lake fringed with Cyperaceae/Leptospermum swamp. The lake became progressively shallower after c. 4800 yr BP, probably due to hydroseral infilling. Surrounding the lake was forest dominated by Dacrydium, Prumnopitys, Metrosideros, and Nestegis. Transition to the Polynesian era appears unclear because the site probably endured a hiatus due to destruction of peat by burning in European times.
Physical mechanisms of the Australian summer monsoon: 2. Variability of strength and onset and termination times

[1] Variability of the Australian monsoon onset, termination, and strength was investigated in terms of the first five major modes of monsoon precipitation found via cyclostationary empirical orthogonal function analysis. They are the El Nino–Southern Oscillation (ENSO) mode, the seasonal cycle, the ENSO transition mode, and the two Madden-Julian oscillation (MJO) modes, respectively. Whereas the seasonal cycle defines the fixed onset (∼5 January) and termination (∼5 March) dates, the presence of the other modes alters these dates. The impact of each mode was investigated after each mode, with a strength corresponding to 1 standard deviation of its variability, was added to or subtracted from the mean seasonal cycle. It is shown that the contribution of each mode to the monsoon precipitation is geographically complex and varies significantly throughout the monsoon period. One striking feature is that the impact of each mode is highly asymmetric with respect to its phase. The negative modes generally affect more significantly the onset, the termination, and the amount of monsoon precipitation. Although each of the four modes makes a unique and tangible contribution, the ENSO mode contributes most significantly to the overall mean and variance of the monsoon precipitation variability. While the positive ENSO (El Nino) mode does not seriously alter the onset and termination times, the negative ENSO (La Nina) mode prolongs the duration of the Australian summer monsoon significantly. Although the contribution to the overall mean is small, the two MJO modes are the most dominating factor controlling the onset and termination times of the Australian summer monsoon.
The European Nitrogen Problem in a Global Perspective

Nature of the problem Reactive nitrogen has both positive and negative eff ects on ecosystems and human health. Reactive nitrogen is formed through the • use of fossil fuels releasing large amounts of nitrogen oxides into the atmosphere and through the production of ammonia by the Haber–Bosch process and using it in agriculture to increase our food, feed and fuel production. While the use of nitrogen as a fertilizer and chemical product has brought enormous benefi ts, losses of fertilizer nitrogen and combustion nitrogen to the environment lead to many side eff ects on human health, ecosystem health, biodiversity and climate.
Lifting potential of solar‐heated aerosol layers

Absorption of shortwave solar radiation can potentially heat aerosol layers and create buoyancy that can result in the ascent of the aerosol layer over several kilometres altitude within 24–48 hours. Such heating is seasonally dependent with the summer pole region producing the largest lifting in solstice because aerosol layers are exposed to sunshine for close to 24 hours a day. The smaller the Angstrøm parameter, the larger the lifting potential. An important enhancement to lifting is the diffuse illumination of the base of the aerosol layer when it is located above highly reflective cloud layers. It is estimated that aerosol layers residing in the boundary layer with optical properties typical for biomass burning aerosols can reach the extra tropical tropopause within 3–4 day entirely due to diabatic heating as a result of solar shortwave absorption and cross‐latitudinal transport. It is hypothesized that this mechanism can explain the presence and persistence of upper tropospheric/lower stratospheric aerosol layers.
Holocene floodplain sediment storage and hillslope erosion within the Rhine catchment

The response of fluvial systems to land use and climate change varies depending on catchment size. While forcing-response mechanisms of small catchments are reasonably well understood, the response of larger drainage basins is less clear. In particular, the impact of land use and climate change on the Rhine system is poorly understood because of the catchment size (185 000 km2) and the long history of human cultivation, which started approximately 7500 years ago. A sediment budget is calculated to specify the amount of alluvial sediment that was deposited during the Holocene and to estimate long-term soil erosion rates. The results suggest that 59±14 X 109 t of Holocene alluvial sediment is stored in the non-alpine part of the Rhine catchment (South and Central Germany, Eastern France, The Netherlands). About 50% of Holocene alluvial sediment is deposited along the trunk valley and the delta (Upper Rhine, Lower Rhine, coastal plain), while the rest is stored along the tributary valleys. The floodplain sediment storage corresponds to a mean erosion rate of 0.55±0.16 t/ha per yr (38.5±10.7 mm/kyr) across the Rhine catchment outside the Alps. This Holocene-averaged estimate amounts for sediments that were delivered to the channel network and is at the lower limit of erosion rates from other studies of different methodology.
Tidal/gravity wave interactions and their influence on the large‐scale dynamics of the middle atmosphere: Model results

Results from a modified version of the quasi-geostrophic model of McLandress and McFarlane [1993] in combination with the tidal model of Forbes [1982a, b] are used to delineate the role of tides in modulating gravity wave momentum fluxes and the ensuing effects on the large-scale circulation of the middle atmosphere for solstice conditions. The influence of the tidal wind fields on the location and strength of the gravity wave drag is strongest in the mesosphere and lower thermosphere where the tidal winds are of the same order as the zonal mean component. Due to the nonlinear dependence on the local wind speed, the daily mean gravity wave drag in the model can differ significantly depending on whether or not tidal variations are included. At middle and low latitudes these differences are largest and occur as a result of the filtering effects of the shorter vertical wavelength diurnal tide. At more polar latitudes where the longer wavelength semidiurnal tide dominates, a slight increase in drag occurs. The interaction between the tidal wind fields and the localized orographic gravity wave momentum flux has important consequences for the in situ generation of planetary scale disturbances. In particular, the amplification of stationary planetary wavenumber 1 is enhanced by the presence of tides. In addition, forcing of nonmigrating tidal modes is predicted to occur as a result of the localized drag.
The impact of chemically amended pig slurry on surface runoff, leachate and greenhouse gasses.

In Ireland, the pig industry is concentrated in a small number of counties. Pig farms typically have a high stocking rate. Therefore, the disposal of slurry in a cost-effective and environmentally-responsible way is a serious issue for farmers. Slurry is commonly applied to land, but this may not be possible if the land is at, or approaching, phosphorus (P) saturation. As pig farmers dispose of slurry in the vicinity of their properties, most of the nearby land is at P saturation, so alternative treatment methods need to be utilised (e.g. constructed wetlands, anaerobic digestion, filtration) or the slurry needs to be transported to another location. These alternatives are not currently financially viable in Ireland. Existing legislation (S.I. 610 of 2010) and recent changes in the implementation of legislation governing the timing and quantities of slurry that may be applied to land, means that pig farmers will no longer be able to exceed the maximum legal application rate to land (from January 2017). European policy aiming to intensify pig production will only accentuate this problem. If pig farmers are forced, in exceptional circumstances, to land apply slurry to unsuitable land, surface and subsurface losses of nutrients and suspended solids (SS) may occur. This could be potentially problematic if the land is located in a critical source area (CSA), an area that is highly likely to pollute receiving waters. In these circumstances, a possible novel solution is to chemically amend the pig slurry prior to landspreading. This would mean that pig farmers may, in exceptional circumstances, utilise the land in the vicinity of their farms for landspreading, without releasing excessive nutrients and SS into receiving waters. However, knowledge gaps exist concerning the type of amendments to be used, the characteristics of the soil on which they can be most effectively used, and their impact on incidental (short-term) and chronic (long-term) losses of nutrients, SS and greenhouse gas (GHG) to surface and subsurface water and the atmosphere. Therefore, the aims of this project were to: (1) identify the most appropriate chemical amendments, and their addition rates, to reduce P losses in runoff from pig slurry based on effectiveness, cost and feasibility; (2) investigate the impacts of these chemical amendments on nutrient losses in leachate, soil properties and GHG emissions; and (3) identify suitable soil types on which to landspread chemically-amended pig slurry.