Miracle-dz/UniFAR-FTUs huggingface dataset:
Geographical Distribution of Climate Feedbacks in the NCAR CCSM3.0

AbstractThis study performs offline, partial radiative perturbation calculations to determine the geographical distributions of climate feedbacks contributing to the top-of-atmosphere (TOA) radiative energy budget. These radiative perturbations are diagnosed using monthly mean model output from the NCAR Community Climate System Model version 3 (CCSM3.0) forced with the Special Report Emissions Scenario (SRES) A1B emission scenario. The Monte Carlo Independent Column Approximation (MCICA) technique with a maximum–random overlap rule is used to sample monthly mean cloud frequency profiles to perform the radiative transfer calculations. It is shown that the MCICA technique provides a good estimate of all feedback sensitivity parameters. The radiative perturbation results are used to investigate the spatial variability of model feedbacks showing that the shortwave cloud and lapse rate feedbacks exhibit the most and second most spatial variability, respectively. It has been shown that the model surface tempera.
Palaeosecular variation of the Earth's magnetic field during the last 10000 years based on the annually laminated sediment of Lake Nautäjarvi, central Finland

A palaeomagnetic study of the Lake Nautajärvi sediment sequence in central Finland demonstrates that varved lake sediments can provideregionally applicable secular variations curves for Holocene stratigraphic correlation and age control. Based on x-ray radiography and digital image analysis techniques we constructed an inherent and continuous varve chronology for the Lake Nautajärvi varve sequence, which covers nearly 10000 years with an estimated counting error of less than ±1% and a mean sedimentation rate of 0.66 mm yr-1. We reconstructed a record of the palaeomagnetic secular variation (PSV) of the Earth's magnetic field in this nearly 7 m long section of clastic-organic varves. Mineral magnetic measurements indicated that pseudosingle-domain magnetite is the major carrier of the remanence. PSV shows many of the familiar features of declination and inclination that have previously been recorded in northern Europe. In addition, the Lake Nautajärvi record contains a continuous record of relative palaeointensity.
Monitoring the atmospheric aerosol optical depth with SPOT data in complex terrain

Two methods - the structure function method and the dispersion coefficient method, both based on the contrast reduction method - are utilized with accompanying sunphotometer observation data and shown to cause a significant reduction in the errors produced when retrieving the aerosol optical depth. When applying the structure function method on the multitemporal SPOT HRV data in estimating the atmospheric aerosol optical depth, the result is affected significantly by the observed geometry, landuse change, non-lambertian surface and terrain effect. Thus, an improved version is proposed in this paper to reduce these effects. Instead of using a single direction method, we expanded it into a multidirectional method that produced a more complete picture of the structure function. In addition, an 'optimal distance index' was further introduced to truncate the abnormal part of the structure functions in some cases. The result shows that the mean error can be reduced from 19% to 6.5% when compared with ground measurements. In addition, the dispersion coefficient method was also examined and improved with a linear regression to correct its bias. Results show than the mean error decreases from 85% to 24%.
Remote sensing and geologic studies of localized dark mantle deposits on the moon

Localized lunar dark mantle deposits (LDMD) are small, smooth low-albedo units of pyroclastic origin commonly found associated with endogenic source craters. Analysis of near-infrared spectra, multispectral images, and radar data obtained for 25 LDMD has led to the identification of three compositional groups of LDMD. Group 1 deposits are composed predominantly of highlands-rich wall rock but also contain a substantial juvenile component, Group 2 deposits are composed largely of mare plug rock material, while Group 3 deposits are rich in a mixture of olivine and pyroxene. Variations in eruption conditions are interpreted to be largely responsible for the varying mineralogy of these three types of deposits.
Ocean Response to the Pinatubo and 1259 Volcanic Eruptions

The ocean’s response to the Pinatubo and 1259 volcanic eruptions was investigated using an ocean general circulation model equipped with an energy balance model. Volcanic eruptions release gases into the atmosphere which increases the aerosol optical depth and acts to reduce the incoming short-wave radiation. For example, there was a huge volcanic eruption (Pinatubo) in 1991 which reduced the global mean radiative forcing by about 3 W m? 2. Two numerical experiments were simulated. The first experiment features the Pinatubo eruption and the second experiment simulates the much larger volcanic eruption that occurred in 1259 when the radiative forcing was reduced by 7 times compared to the Pinatubo event. With the reduced radiative forcing due to the Pinatubo eruption at about 3 W m? 2 and 1259 eruption at about 21 W m? 2, the global mean sea surface temperature (SST) decreased to its lowest in the second year after each event by about 0.4oC and 1.6oC, respectively. Sea surface salinity (SSS) increased substantially in the northern North Pacific, northern North Atlantic, and the Southern Ocean. The reduced SST together with SSS increased ocean convection, which yielded an increase in North Atlantic Deep Water, Antarctic Bottom Water, and North Pacific Intermediate Water production and their outflows. The increase in overturning circulation eventually increased the pole-ward ocean heat fluxes. In conclusion, huge volcanic eruptions perturb the ocean substantially and their hallmarks last for more than a decade, confirming the importance of volcanic eruptions in illustrating the decadal-climate variability recorded in the paleoclimate proxy data for the past million years.
Oblique convergence of the crust driven by basal forcing: implications for length-scales of deformation and strain partitioning in orogens

SUMMARY We investigate the effects of oblique convergence on crustal thickening by modelling the crust as a thin viscous sheet. Crustal deformation is driven by basal velocity boundary conditions representing the kinematics of the underlying convergent mantle lithosphere, which is assumed to detach and subduct. The crustal sheet is coupled to the basal velocity field by a weak simple shear layer, which exerts a traction on the base of the sheet. The use of basal velocity boundary conditions with a thin-sheet model is shown to be valid provided coupling with the base is weak and deformation extends over a horizontally wide zone in comparison to the thickness of the sheet. The effect of the mantle lithosphere on crustal deformation can be shown to depend on the non-dimensional Ampferer number, Am, which represents the relative strengths of the crust and the weak basal shear zone. Analytical and numerical model results for small amounts of normalized convergence show that the ratio of horizontal length-scales for normal and transcurrent crustal deformation is 2, for both linear and non-linear viscous rheologies. The length-scales depend on the relative strength of the crust and the basal shear zone, convolved with a forcing length-scale from the boundary conditions. For obliquely incident velocities, the length-scale ratio is between 2 and 1, the exact value depending on the power-law exponent of the rheology, and the relative magnitude of the normal and transverse velocity components driving deformation. The model results for the ratio of normal to transcurrent deformation length-scales are different from those found by using a side-driven viscous thin-sheet model (England, Houseman & Sonder 1985; Sonder, England & Houseman 1986). We propose that this difference may be used as a test to distinguish the primary driving mechanism for large-scale orogenic deformation. If the deformation mechanism corresponds to pure shear of the whole lithosphere without significant basal tractions, we expect the deformation length-scale to be determined by the scale of the applied boundary conditions and buoyancy forces in the crust. The normal/transcurrent length-scale ratio for this case, in early stages of deformation, will be approximately 4. Alternatively, if the results presented here are more appropriate, then we expect the deformation length-scale to be determined by the intrinsic relative strengths of the crust and underlying basal shear zone. The corresponding normal/transcurrent length-scale ratio for this case, in early stages of deformation, will be between 2 and 1. On the basis of a comparison of the predicted length-scales of deformation with the length-scale over which the velocity boundary conditions are applied, we suggest that long, narrow, linear orogens such as the Andes are controlled by basal boundary conditions, whereas the Himalayan-Tibetan orogen has dimensions consistent with either basally or side-driven deformation.
Influence of Destructuration of Soft Clay on Time-Dependent Settlements: Comparison of Some Elastic Viscoplastic Models

AbstractThe time-dependent settlement of soft soils following the application of surface loading may be modeled using elastic viscoplastic constitutive models to describe the soil behavior. For applied loadings that increase the stresses toward and beyond the in situ yield stress, the predicted behavior is strongly influenced by the associated breakdown of the clay structure and the way in which this is modeled. Four elastic viscoplastic models are compared and it is shown that, despite presentational differences, all calculate creep rate in fundamentally the same manner. This paper describes some predictions for a hypothetical case prediction exercise organized recently by the Norwegian Geotechnical Institute that compared different calculation methods used in settlement analyses of soft soil. The results presented here are from a one-dimensional coupled consolidation analysis implemented in a spreadsheet-based software and using a finite-element program. Parameters were obtained from an oedometer test, .
Discrete parameterization of hydrological models: Evaluating the use of parameter sets libraries over 900 catchments

This article describes an alternative to the optimization strategies classically adopted to calibrate the parameters of rainfall‐runoff models. This new method, called discrete parameterization, relies on the sole use of the prior information on parameters gained on other catchments. The optimum parameter set is simply searched within a collection (a library) of predefined optima. This library is composed of parameter sets representing a large number of actual catchments. The method was tested on a set of 900 catchments (from Australia, France, and the United States) using two daily lumped rainfall‐runoff models and was compared to more classical calibration approaches. Results are very similar for both models. Although the discrete parameterization method is not as efficient as a classical global search calibration approach when long time series are available for calibration, it provides more robust parameter sets when flow time series available for calibration becomes shorter than 2 years. This makes the method particularly interesting in the cases of poorly gauged catchments where available flow records are short. In case of limited data, the advantage of the proposed approach over the classical calibration approaches was more significant for the more complex model. On our set of 900 catchments, the optimum parameter set is generally selected among parameter sets from the library corresponding to catchments spatially close to the studied catchment. However other criteria of physical similarity may be relevant to select the donor catchment in the library.
Compression characteristics and index properties of tills and intertill clays in southern Saskatchewan, Canada

Compression characteristics and index properties of unweathered tills and clays from repeated glaciations follow a predictable pattern at 10 sites along a 1300-km transect across southern Saskatchewan. A surface ablation melt-out till of the Battleford Formation is normally consolidated, a basal melt-out till of the Battleford Formation is moderately overconsolidated (σp′ = 400–750 kPa), and the older (pre-Battleford) tills and intertill clays are heavily overconsolidated (1800 ± 200 kPa). Variation in lithology, as indicated by Atterberg limits, is small within formations which reflected in the compression index. The older tills of the Sutherland Group are highly plastic compared with the younger tills of the Saskatoon Group. The in situ dry density of the youngest (Battleford) till is slightly above 100% maximum Proctor density. The in situ dry density of the older (pre-Battleford) tills is at or above the 100% maximum modified Proctor density. At these high densities the in situ degree of saturation is.
Trend Analysis of Canadian Avalanche Accidents: The Avaluator Avalanche Accident Prevention Card Has Not Reduced the Number of Accidents

The Avaluator Avalanche Accident Prevention Card (Haegeli & McCammon, 2006), a Canadian government avalanche prevention initiative, was designed to help recreationists avoid acci- dents, and therefore, to reduce the overall number of avalanche accidents in Canada involving recre- ational users. McCammon and Haegeli (2006) argued that the Avaluator will cause a statistically de- tectable reduction in the number of avalanche accidents within 3 or 4 seasons after its adoption. However, research has revealed that (a) the data behind the Avaluator's Obvious Clues are not avail- able for inspection (Uttl, Uttl, & Henry, 2008; Floyer, 2008); (b) Haegeli and McCammon (2006) inap- propriately excluded over 1,148 avalanche accident reports from their sample due to missing values and based the prevention values on only 252 US accidents; (c) several independent studies have found the Obvious Clues prevention values published in the Avaluator to be grossly inflated (Uttl, Henry, & Uttl, 2008a,b; Floyer, 2008; Uttl, Kisinger, Kibreab, & Uttl, 2009). We examined McCammon and Haegeli's (2006) prediction. Our trend analysis of avalanche accidents in Canada revealed that the number of accidents has sharply increased rather than decreased following the Avaluator's adop- tion. This increase is consistent with findings that the Avaluator's prevention values are grossly in- flated and give users a false sense of confidence in slope stability.
Expert System Methodology for Evaluating Reductive Dechlorination at TCE Sites

An expert knowledge site-screening methodology has been developed to evaluate naturally occurring reductive dechlorination as a remedial option for sites with TCE-contaminated groundwater. This methodology combines a causative model for the reductive dechlorination of TCE and expert knowledge within a Bayesian Belief Network. The knowledge base for this expert system was obtained from 22 experts via an expert elicitation protocol. The resulting expert system can be used to aid environmental decision making by evaluating the adequacy of reductive dechlorination at TCE-contaminated sites. Comparisons between this expert system and a commonly used screening tool show that this expert system produces predictive models that may better discriminate between locations that were sampled. The 22 elicitations revealed different beliefs and assumptions among experts about the biochemical processes involved in reductive dechlorination. The decision-making value of some types of evidence is a matter of dispute; however.
Detrital zircon and isotopic constraints on the crustal architecture and tectonic evolution of the northeastern Pamir

New detrital zircon and isotopic (Nd and Sr) analyses from the eastern Pamir provide information on the depositional age and tectonic terrane affiliation of regional metamorphic terranes. Our results show the following. First, detrital zircon analyses from metasedimentary units along the Kongur Shan extensional system dominantly yield Triassic maximum depositional ages, with a similar age distribution to the Tibetan Songpan‐Ganzi terrane. Further, zircon analyses from quartzofeldspathic gneisses in the core of the Muztaghata massif show the protoliths are Triassic granites. These units are interpreted to be part of the Permian‐Triassic Karakul‐Mazar arc‐accretionary complex terrane. Second, εNd(0) compositions of Triassic granites overlap with other metasedimentary units not analyzed for detrital zircons and are also interpreted to be part of the Karakul‐Mazar terrane. Third, schists in the Sares‐Muztaghata gneiss dome structurally above Triassic orthogneisses yield an Ordovician maximum depositional age with a distinct detrital age distribution similar to the Tibetan Qiangtang terrane and are interpreted to be part of the Central Pamir terrane. Finally, Triassic and Ordovician schists along the Muztaghata massif record an Early Jurassic metamorphic event interpreted to date south‐directed subduction of the Karakul‐Mazar terrane beneath the Central Pamir during final closure of the Paleo‐Tethys. These results, integrated with previously published results and field relations, reveal a complex Mesozoic to Cenozoic interleaving of tectonic terranes in the eastern Pamir with emplacement of the Karakul Mazar terrane both above and below the Kunlun and Central Pamir terranes to the north and south, respectively.
Optimized Threshold Algorithm of Envisat Waveform Retracking over Coastal Sea

Waveform retracking is an effective method to improve the accuracy of sea surface height measurement with the satellite altimetric technique. The improved threshold retracking algorithm is optimized in the paper. Several waveform retracking algorithms such as the 5-β parametric fitting algorithm, off center of gravity, Ocean1 and threshold are also analyzed at the same time. Then a waveform retracking system is programmed. Several retracking methods are used to retrack the EnviSat waveform over the Mediterranean Sea. The optimized threshold retracking algorithm is the more robust retracking method and more suitable for the EnviSat waveform retracking over the coastal Med.
Stable-unstable flow of geothermal fluids in fractured rock

Density-driven geothermal flow in 3-D fractured rock is investigated and compared with density-driven haline flow. For typical matrix and fracture hydraulic conductivities, haline flow tends to be unstable (convecting) while geothermal flow is stable (non-convecting). Thermal diffusivity is generally three orders of magnitude larger than haline diffusivity and, as a result, large heat conduction diminishes growth of geothermal instabilities while low mass diffusion enables formation of unstable haline ‘fingering’ within fractures. A series of thermal flow simulations is presented to identify stable and unstable conditions for a wide range of hydraulic conductivities for matrix and fractures. The classic Rayleigh stability criterion can be applied to classify these simulations when fracture aperture is very small. However, the Rayleigh criterion is not applicable when the porous matrix hydraulic conductivity is very small, because stabilizing fracture–matrix heat conduction is independent of matrix hydraulic conductivity. In that case, the numerically estimated critical fracture conductivity is nine orders of magnitude larger than the theoretically calculated critical fracture conductivity based on Rayleigh theory. The numerical stability analysis presented here may be used as a guideline to predict if a geothermal system in 3-D fractured rock is stable or unstable.
Regional and teleseismic analysis of underground nuclear explosion waveforms and constraints for shear wave excitation mechanisms

[1] Regional and teleseismic waveforms of underground nuclear explosions (UNEs) at the Balapan and the Nevada test sites are analyzed to understand the nature of shear waves excited from UNEs. The phase composition of wavefields in the source and receiver regions is examined using a source array frequency-wave-number analysis and polarization analyses. It is observed that regional mantle-lid shear waves, Sn, often develop strongly. On the other hand, observed teleseismic shear waves from UNEs are much weaker than those from earthquakes. Source array analyses of the shear waves from UNEs display coherent energy that is polarized in a certain azimuthal direction. The observation of coherent shear energy in different UNEs suggests that the shear energy is excited in a consistent manner at every UNE. We constrain the dominant shear wave excitation mechanism from the observed shear wave features. The observations appear to be consistent with the tectonic release model with conical rock cracking.
Physiological response and ion accumulation in two grasses, one legume, and one saltbush under soil water and salinity stress

A glasshouse–pot trial using four levels of soil moisture (>100%, 90%, 75%, and 60% field capacity) and three levels of salinity (1.0 dSm–1, 3.5 dSm–1, and 6.0 dSm–1) was done to evaluate Na+, K+, and Cl− accumulation capacity and the physiological responses (net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, quantum efficiency of PSII, and non‐photochemical quenching) in Melilotus siculus, Tecticornia pergranulata, Cynodon dactylon , and Thinopyrum ponticum. Results reveal that the combined effects of soil water and salinity had a significant effect on Na+ and Cl− accumulation and not on that of K+. Concentrations of Na+ and Cl− and non‐photochemical quenching increased significantly whereas, the net photosynthetic rate (Pn), stomatal conductance (gs), and intercellular CO2 concentration decreased significantly in the tested plants, because of salinity. Salinity had no significant effect on the maximum quantum yield and relative water contents in shoots. Soil moisture had a significant effect on Na+, K+, and Cl− accumulation and the physiological responses in tested plants. T. pregranulata accumulated the highest concentrations of Na+ and Cl− and had the lowest Pn. C. dactylon accumulated the lowest concentrations of Na+ and Cl−, whereas Pn was the highest. No strong positive correlation between Pn and gs was evident in tested plants. We indicate that the reduced physiological performance was because of non‐stomatal activities. Na+ and Cl− accumulation capacity in the tested plants was in the following order: T. pergranulata>M. siculus>T. ponticum>C. dactylon. C. dactylon, a C4 plant, accumulated lower salt ions than the other three C3 plants. Copyright © 2015 John Wiley & Sons, Ltd.