Miracle-dz/UniFAR-FTUs huggingface dataset:
Detection of small single trees in the forest–tundra ecotone using height values from airborne laser scanning

Because of global warming, it is assumed that the arctic and alpine tree lines will advance northwards into the tundra and upwards into mountainous regions. Methods are needed to monitor these advances. Airborne laser scanning has recently been introduced for detection of small pioneer trees that form the advanced alpine tree line. The objective of this study was to analyze the capability of high-density airborne laser scanning data used for detecting such individual small trees in the transition between the mountain forest and the alpine zone, the forest–tundra ecotone. The study used field and laser data collected along a 1500 km transect stretching from northern Norway (69°3′ N) down to the southern part of the country (58°3′ N). In the field, 744 trees of mountain birch, Norway spruce, and Scots pine were geolocated with centimetre accuracy, and they were measured for height, root collar diameter, and crown diameter. Tree heights ranged between 0.02 and 7.80 m. The laser data were acquired in two separate acquisitions with mean pulse densities of 6.8 m−2 and 8.5 m−2, respectively. Laser echoes with relative height values greater than zero within the individual tree crown polygons were used as a criterion for a successful tree detection. The detection success for trees taller than 1 m was 90%; however, for trees shorter than 1 m, the corresponding value was 49%. The highest detection success was found for spruce. Generalized linear models and a generalized linear mixed model with binary responses (detected/not detected) were applied to evaluate the effects of tree height, tree crown area, tree species, geographic location along the latitude gradient, and region on successful detection. Although they were highly correlated, tree height and tree crown area turned out to be the variables showing high significance (p ≤0.001) in all of these models.
Conservation status of eight rare (Apiaceae) taxa from Syria

Habitat fragmentation is one of the main threats to biodiversity. Hence, many species nowadays occur mainly in small and isolated populations (such as endemic species), and will be expected to face extinction. The precise evaluation of the conservation status of a particular species is a necessary condition to prevent its extinction. The correct assessment of conservation status of a species is the most significant tools in biodiversity conservation.Extensive field studies and a large number of specimens collected from N-W Syria and examining herbarium specimens deposited at some limited Syrian herbaria. Ecological properties were also observed in the field. Threatened categories are proposed according to IUCN Red List Categories Version 3.1. Conservation status of eight species is evaluated for Syria and global level. Threatened categories of the species are determined as • NT for Peucedanum mucronatum, Johrenia dichotoma, and Eryngium desertorum locally, and changed for the first two species to LC on globally (the latter is endemic only to the region). • VU for Chaerophyllum libanoticum, Ferulago cassia, and Johrenia porteri for local and global levels. • EN for Ferula hermonis for both the local and global levels. • CR for Eryngium maritimum for the local level, but decreased to NT on the global level.The taxa mainly distributed at coastal areas and Mountains of east Mediterranean. This region is under various threats because of Human disturbance, Agricultural activities and repeated forest fires in recent years. Therefore, in situ and ex situ conservation measures should be enforced for the species
Common-reflection-surface-based workflow for diffraction imaging

Imaging of diffractions is a challenge in seismic processing. Standard seismic processing is tuned to enhance reflections. Separation of diffracted from reflected events is frequently used to achieve an optimized image of diffractions. We present a method to effectively separate and image diffracted events in the time domain. The method is based on the common-reflection-surface-based diffraction stacking and the application of a diffraction-filter. The diffraction-filter uses kinematic wavefield attributes determined by the common-reflection-surface approach. After the separation of seismic events, poststack time-migration velocity analysis is applied to obtain migration velocities. The velocity analysis uses a semblance based method of diffraction traveltimes. The procedure is incorporated into the conventional common-reflection-surface workflow. We apply the procedure to 2D synthetic data. The application of the method to simple and complex synthetic data shows promising results.
Monitoring Temporal Changes in Multivariate Classifications

Multivariate classifications have been used extensively to make inductive generalizations about place or objects under study. If classifications are dynamic, changing as the variables that define them change, then these generalizations and the policies and strategies based on these generalizations may not hold over time. This paper presents a replicable method for monitoring temporal changes in a classification at the structural and group levels. The method is then illustrated in an empirical example using longitudinal data that relate to the economies of a selected set of geographic areas.
Aeromagnetic Anomalies over the Area of Unzendake Volcano

An aeromagnetic survey flight over the area of Unzendake volcano was conducted in August, 1991, after the commencement of this time eruption, and a geomagnetic anomaly map was derived from collected data. The comparison of magnetic anomalies with the ones in 1981 by the New Energy Development Organization was attempted in order to judge whether there was a significant change of magnetic anomaly pattern for these ten years. However, no large variations with wavelengths more than 6 km were detected. The magnetic anomalies of the area revealed a close correlation with the topography. Average magnetization of normally magnetized terrain was estimated to 2.9 A/m from statistical analysis, and the effect of topographic relief was removed. The residuals were interpreted in terms of a graben structure filled with magnetic volcanics and shallower lateral inhomogeneity of magnetization. And the possibility was pointed out that an old volcanic unit unknown around Sarubayama might have considerable extension under the surface.
Guided Waves Along Hydraulic Fractures

Hydraulic fracturing as an oil and gas reservoir stimulation technique aims at creating large fractures around a borehole, which improves the inflow of hydrocarbons at production wells, as well as the injectivity of water at injection wells. For hydraulic fracturing experiments it is desirable to find techniques to estimate fracture dimensions to aid the reservoir engineer in the fracture treatment or design. In this abstract we numerically model the propagation of guided waves along hydraulic fractures. These guided waves could be used in wellbore measurements to estimate fracture length or volume. It is well-known that guided waves can propagate along dry or fluid-filled fractures. In the geophysical community fractures are often described by the linear-slip model and the guided waves that are associated with this model are referred to as generalized Rayleigh waves. Previous studies show that both pressure symmetric as well as pressure anti-symmetric generalized Rayleigh waves exist. In this abstract we focus on hydraulic fractures which are mechanically open, i.e. the fractures faces are disconnected and do not show substantial mechanical contact. As a result the fluid in the fracture is connected and we describe the fracture by a thin fluid-filled layer model. Numerically modeled seismograms show that for these kind of fractures not only generalized Rayleigh waves exist, but also a slow and strongly dispersive guided wave. We will refer to this wave as the slow channel wave, because it appears to be the two-dimensional equivalent of the cylindrical tube wave. The slow channel wave is absent in the linear-slip model because this model does not incorporate the explicit boundary condition of zero shear stresses at fluid-solid interfaces. During hydraulic impedance testing (HIT) a pressure pulse is send down into the wellbore by opening the fluid pump during the hydraulic fracturing treatment. Some studies claim the observation of the reflection of a slow wave in the fluid at the tip of the fracture. In the low-frequency limit the channel wave corresponds to the slow fluid wave related to the waves that are exited in the fracture during HIT-experiments. This also resolves a possible ambiguity when both geophysicists and reservoir engineers talk about fracture waves.
Ice thickness and basal conditions of vestfonna ice cap, eastern svalbard

Pettersson, R. , Christoffersen, P., Dowdeswell, J.A. , Pohjola, V. , Hubbard, A. and Strozzi, T. , 2011. Ice thickness and basal conditions of Vestfonna Ice Cap, Eastern Svalbard. Geografiska Annaler: Series A, Physical Geography, 93, 311–322. DOI: 10.1111/j.1468‐0459.2011. 00438.x Abstract We combined ground‐based pulsed radar data collected in 2008–2009 with airborne radio‐echo sounding data acquired in 1983 and 1986 over Vestfonna ice cap, Svalbard. The airborne dataset mainly covers the fast‐flowing outlet glaciers and the marginal zone, while the ground‐based data explicitly cover the interior part of the ice cap. The data presented here are thus the first complete estimate of bed topography and ice thickness. The subglacial landscape undulates with elevations between −160 and +410 m above sea level. The mean ice thickness is 186 m and the total ice area and volume are 2402 km2 and 442 ± 0.6 km3, respectively. This is a much smaller volume than those derived from empirical volume‐area scaling relationships currently used to estimate regional‐to‐global glacier volumes. This difference may depend on local conditions for Vestfonna and emphasizes the need to include more volume observations in the derivations of volume‐area scaling parameters. We also derive basal reflectivity as a proxy for thermal conditions at the bed. Basal reflectivity values suggest that fast‐flowing outlet glaciers are underlain by temperate conditions. The geometric boundaries and basal conditions for Vestfonna will be critical additions to the development of numerical models of the ice cap and to the estimation of more accurate area‐volume scaling parameters.
Strip footings on a three layer soil system: theory of elasticity approach

Abstract An attempt has been made in this paper to predict deformations and stresses built up in a three layer soil medium supporting a strip footing. Soil layers have been considered to have different elastic modulii. The governing differential equations have been derived in terms of horizontal and vertical displacements using the theory of elasticity and solved numerically using the finite difference method. This paper also includes the parametric study which was undertaken to understand the influence of both relative thicknesses and the relative elastic modulii of various soil layers on vertical displacements and stresses in the entire medium. Due consideration has been given to the range of parametric values, normally found valid in case of foundations of conventional and the industrial structures. The analysis clearly highlights that vertical displacement of the footing reduces with increase in upper and middle soil layer thicknesses and with the ratio of modulii of these layers. Presence of a stiffer middle layer helps in reducing the vertical stresses at the top of lower soil layer.
The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years

Periods of widespread warmth or cold are identified by positive or negative deviations that are synchronous across a number of temperature-sensitive proxy records drawn from the Northern Hemisphere. The most significant and longest duration feature during the last 1200 years is the geographical extent of warmth in the middle to late 20th century. Positive anomalies during 890 to 1170 and negative anomalies during 1580 to 1850 are consistent with the concepts of a Medieval Warm Period and a Little Ice Age, but comparison with instrumental temperatures shows the spatial extent of recent warmth to be of greater significance than that during the medieval period.
Low‐velocity zones along the San Jacinto Fault, Southern California, from body waves recorded in dense linear arrays

We derive high‐resolution information on low‐velocity fault zone (FZ) structures along the San Jacinto Fault Zone (SJFZ), Southern California, using waveforms of local earthquakes that are recorded at multiple linear cross‐fault arrays. We observe clear across‐fault delays of direct P and S waves, indicating damage zones at different segments of the SJFZ. We then compute synthetic traveltimes and waveforms using generalized ray theory and perform forward modeling to constrain the FZ parameters. At the southern section near the trifurcation area, the low‐velocity zone (LVZ) of the Clark branch has a width of ~200 m, 30–45% reduction in Vp, and ~50% reduction in Vs. From array data across the Anza seismic gap, we find a LVZ with ~200 m width and ~50% reduction in both Vp and Vs, nearly as prominent as that on the southern section. We only find prominent LVZs beneath three out of the five arrays, indicating along‐strike variations of the fault damage. FZ‐reflected phases are considerably less clear than those observed above the rupture zone of the 1992 Landers earthquake shortly after the event. This may reflect partially healed LVZs with less sharp boundaries at the SJFZ, given the relatively long lapse time from the last large surface‐rupturing event. Alternatively, the lack of observed FZ‐reflected phases could be partially due to the relatively small aperture of the arrays. Nevertheless, the clear signatures of damage zones at Anza and other locations indicate very slow healing process, at least in the top few kilometers of the crust.
Dyes as tracers for vadose zone hydrology

Dyes are important tracers to investigate subsurface water movement. For more than a century, dye tracers have provided clues about the hydrological cycle as well as flow and transport processes in the subsurface. Groundwater contamination often originates in the vadose zone. Agrochemicals applied to the soil surface, toxic compounds accidentally spilled by human activities, and contaminants released from waste repositories leach through the vadose zone and can ultimately pollute groundwater resources. Dyes are an important tool to assess flow pathways of such contaminants. This review compiles information on dyes used as hydrological tracers, with particular emphasis on vadose zone hydrology. We summarize briefly different human‐applied tracers, including nondye tracers. We then provide a historical sketch of the use of dyes as tracers and describe newer developments in visualization and quantification of tracer experiments. Relevant chemical properties of dyes used as tracers are discussed and illustrated with dye intermediates and selected dye tracers. The types of dyes used as tracers in subsurface hydrology are summarized, and recommendations are made regarding the use of dye tracers. The review concludes with a toxicological assessment of dyes used as hydrological tracers. Many different dyes have been proposed as tracers for water movement in the subsurface. All of these compounds, however, are to some degree retarded by the subsurface medium. Nevertheless, dyes are useful tracers to visualize flow pathways.
Phenomenology of the low-frequency variability in a reduced-gravity, quasigeostrophic double-gyre model

Abstract The low-frequency variability of the oceanic wind-driven circulation is investigated by use of a reduced-gravity, quasigeostrophic model with slight variations on the classic double-gyre wind forcing. Approximately 30 eddy-resolving simulations of 100–1000 years duration are analyzed to determine the types of low-frequency variability and to estimate statistical uncertainties in the results. For parameters close to those leading to a stable antisymmetric solution, the system appears to have several preferred phenomenological regimes, each with distinct total energy levels. These states include a high-energy quasi-stable state; a low-energy, weakly penetrating state; and a state of intermediate energy and modest eddy/ring generation. The low-frequency variability of the model is strongly linked to the irregular transitions between these dynamical regimes. For a central set of reference parameters, the behavior of the system is investigated for each period in which the total energy remains in certa.
New Data Systems and Products at the Permanent Service for Mean Sea Level

ABSTRACT Holgate, S.J.; Matthews, A. ; Woodworth, P.L. ; Rickards, L.J.; Tamisiea, M.E. ; Bradshaw, E. ; Foden, P.R. ; Gordon, K.M. ; Jevrejeva, S. , and Pugh, J., 2013. New data systems and products at the Permanent Service for Mean Sea Level. Sea-level rise remains one of the most pressing societal concerns relating to climate change. A significant proportion of the global population, including many of the world's large cities, are located close to the coast in potentially vulnerable regions such as river deltas. The Permanent Service for Mean Sea Level (PSMSL) continues to evolve and provide global coastal sea-level information and products that help to develop our understanding of sea-level and land motion processes. Its work aids a range of scientific research, not only in long-term change, but also in the measurement and understanding of higher frequency variability such as storm surges and tsunamis. The PSMSL has changed considerably over the past 10 years, and the aim of this paper is to update the community about these changes as well as provide an overview of our continuing work.
Università Della Svizzera Italiana Usi Technical Report Series in Informatics Probabilistic Fifo Ordering in Publish/subscribe Networks

In a best-effort publish/subscribe network, publications may be delivered out of order (e.g., violating FIFO order). We contend that the primary cause of such ordering violations is the parallel matching and forwarding process employed by brokers to achieve high throughput. In this paper, we present an end-to-end method to improve event ordering. The method involves the receiver (and minimally the sender) and otherwise uses the broker network as a black box. The idea is to analyze the dynamics of the network, and in particular to measure the delivery delay and its variation, which is directly related to out-of-order delivery. With these measures, receivers can determine a near-optimal latch time to defer message delivery upon the detection of a hole in the message sequence number. We evaluate the performance of this ordering scheme empirically in terms of the reduction in out-of-order deliveries, the delay imposed by the latch time, and its self-adjustment with variable network conditions and input loads.
Three-dimensional visualization analysis for marine field data based on 3D-GIS

Considering large, complex and multi-dimensional marine field data, the general representation and analysis methods based on 2D GIS can not meet the requirements of Ocean Research. For multi-dimensional marine sampling data of sea water properties (ARGO sampling data, ship measured data, etc.), three dimensional interpolation and visual analysis methods can be used to reveal the distribution of sea water properties (such as temperature and salinity), and it is an effective way to detect regional anomaly of marine phenomenon. In order to handle three dimensional sampling data of sea water properties, this paper developed a three dimensional volume visualization analysis GIS component with OpenGL and C++. Three visualization analysis methods are designed and presented, including three-dimensional volume visualization, three dimensional slicing and cutting analysis and three-dimensional contour surface analysis. Example test is conducted, and the test result shows the proposed methods can be effectively used for ocean data analysis.
Indian Ocean Rossby waves detected in HYCOM sea surface salinity

Rossby waves have been well identified in satellite derived sea surface height (SSH), sea surface temperature (SST) and ocean color observations. Studies of Rossby waves have yet to include sea surface salinity (SSS) as a parameter, largely because presently available in situ measurements of salinity lack sufficient spatial and temporal coverage, and as of now no methods are available for measuring salinity from a satellite. In this paper, we demonstrate that Rossby waves can be observed in SSS in the Indian Ocean by using simulations of the 1/12° global Hybrid Coordinate Ocean Model (HYCOM). HYCOM results compared favorably to SSS data provided by Argo floats and the World Ocean Atlas 2005 (WOA05) in selected grid boxes in the Indian Ocean. Hovmöller diagrams of HYCOM SSS anomalies and gradient show the distinct westward propagating signature of Rossby waves, with a steeper slope in longitude/time plots further from the equator. The propagation speeds, calculated from a 2D Radon Transform are comparable with new theoretical speeds for Rossby waves. Annual westward propagating signals in the SSS simulations at most of the latitudes in the Indian Ocean coincide with previous studies. We hope that future studies of Rossby waves in SSS using model results and eventually satellite measurements of salinity data will allow a better understanding of Rossby wave dynamics.
Data capture for multiscale modelling of the Lourinhã Formation, Lusitanian Basin, Portugal: an outcrop analogue for the Statfjord Group, Norwegian North Sea

Abstract Current recovery from the Statfjord Group in the majority of the fields on the Tampen Spur is less than 50%. A contributing factor to this is an incomplete understanding of multiscale heterogeneities, their distributions within a range of fluvial geobodies and their lateral extent and morphology in inter-well areas. Sedimentary heterogeneities have been modelled, together with petrophysical parameters, at a variety of scales. The modelled properties at a given scale were upscaled to the next level of heterogeneity, thus better honouring effective property values. The use of outcrop analogues is still a key tool for understanding facies relationships and the stratigraphic development of subsurface hydrocarbon-bearing reservoirs. The Lourinhã Formation, Portugal, was used as an analogue to collect both qualitative and quantitative data consistently following a three-phase workflow to capture data at various scales of heterogeneity. Traditional field data collection techniques have been supplemented with the collection of LiDAR data. A digital workflow utilizing interlinked datasets facilitates rapid data analysis and better data visualization with results that are more easily utilized in multiscale modelling studies. These scaled models were used to increase our understanding of the effect on flow of lithofacies and facies association distributions together with internal architectural elements and heterogeneities.