Miracle-dz/UniFAR-FTUs huggingface dataset:
On nonsinusoidal waves at the Earth‧s magnetopause

The authors have examined ISEE 1 and 2 data during an interval of multiple magnetopause crossings along the flanks of the tail on January 22, 1978. During the event the interplanetary magnetic field was mainly northward. They found that the surface waves on the magnetopause were nonsinusodial with steepened sunward facing surfaces. This result is consistent with observations reported for an analogous event by Chen et al. The dawn-dusk electric field E in the low-latitude boundary layer was [approximately]10 kV/R[sub E] which is much greater than the [approximately]l kV/R[sub E] dawn-dusk E field typical of the sunward convecting plasma sheet plasma. The ratio of the dawn-dusk E field in the LLBL to the dusk-dawn E in the magnetosheath was [approximately]1/3. The authors propose that the magnetic field in the magnetosheath modulates the wave form in a way that may result in an anomalous transport of momentum across the magnetopause.
Comments on “Predictability of Winter Climate over the North Atlantic European Region during ENSO Events”

The predictability of winter climate over the North Atlantic–European (NAE) region during ENSO events is investigated. Rather than employing traditional composite analyses, the authors focus on the impacts of six individual events: three El Nin˜o events and three La Nin˜a events. The investigation is based on the analysis of ensemble simulations with an atmospheric GCM forced with prescribed sea surface temperatures (SST) for the period December 1985–May 2001, and on observations. Model experiments are used to separate the respective roles of SST anomalies in the Indo-Paciﬁc basin and in the Atlantic basin. A signiﬁcant (potentially predictable) climate signal is found in the NAE region for all six ENSO events. However, there are notable differences in the impacts of individual El Nin˜o and La Nin˜a events. These differences arise not simply from atmospheric internal variability but also because the atmosphere is sensitive to speciﬁc features of the SST anomaly ﬁelds that characterize the individual events. The different impacts arise partly from differences in Indo-Paciﬁc SST and partly from differences in Atlantic SST. SST anomalies in both ocean basins can inﬂuence tropical convection and excite a Rossby wave response over the North Atlantic. The evidence presented here for the importance of Atlantic Ocean conditions argues that, in the development of systems for seasonal forecasting, attention should not be focused too narrowly on the tropical Paciﬁc Ocean.
INFLUENCE OF CEMENTATION ON LIQUEFACTION OF SANDS

A study is reported which attempted to determine how cementation serves to resist liquefaction. Information on the relative influences of cementation and unit weight is reported since these two parameters sometimes produce similar effects. The study also determined what happens when soil is cemented in a nonhomogeneous manner, since this condition is likely in natural or man-modified soil. The behavior of cemented soil under loadings beyond those produced in conventional triaxial tests was studied, because the positive effects of cementation can be reduced under certain type of complex field stress conditions. When saturated and subjected to seismic loading, the cemented sand can liquefy, but its resistance to liquefaction is greater than that of the uncemented sand. It is noted that the influence of cementation on liquefaction resistance is important, and should be considered in engineering projects.
The development and testing of a water balance model for climate impact assessment: Modeling the Sacramento Basin

Within the next few decades, changes in global temperature and precipitation patterns caused by increasing atmospheric concentrations of carbon dioxide and other trace gases are likely to appear. At present, the authors are unable to evaluate the regional hydrologic impacts of such climatic changes with any certainty. Using modified water balance methods, a model of a critical hydrologic basin, the Sacrament Basin in California, is developed and tested for the purposes of investigating the effects on water availability of changes in climate. This basin was chosen because of the importance of its water supplies to agricultural and industrial productivity and because of the quality and quantity of the hydrologic data available. The water balance model is capable of reproducing both the magnitude and the timing of monthly and seasonal runoff, as well as changes in soil moisture conditions. The results suggest that the application of such models may provide considerably more information on regional hydrologic effects of climatic changes than is currently available. Such information is likely to have important ramifications for long-range water resource planning, for agricultural water development and conservation, and for industrial water use over the next several decades.
Development and steady states of transverse dunes: A numerical analysis of dune pattern coarsening and giant dunes

We investigate the development and steady states of transverse dunes for ranges of flow depths and velocities using a cellular automaton dune model. Subsequent to the initial bed instability, dune pattern coarsening is driven by bed form interactions. Collisions lead to two types of coalescence associated with upstream or downstream dominant dunes. In addition, a single collision‐ejection mechanism enhances the exchange of mass between two adjacent bed forms (throughpassing dunes). The power law increases in wavelength and amplitude exhibit the same exponents, which are independent of flow properties. Contrary to the wavelength, dune height is limited not only by flow depth but also by the strength of the flow. Superimposed bed forms may propagate and continuously destabilize the largest dunes. We identify three classes of steady state transverse dune fields according to the periodicity in crest‐to‐crest spacing and the mechanism of size limitation. In all cases, the steady state is reached and maintained through the dynamic equilibrium between flow strength and dune aspect ratio. In the limit of low flow strength, where it becomes the primary factor of size limitation, the bed shear stress in the dune trough regions is close to its critical value for motion inception. Comparisons with natural dune fields suggest that many of them may have reached a steady state. Finally, we infer that the sedimentary patterns in the model may be used to bring new constraints on the development of modern and ancient dune fields.
Estimation of Continental Precipitation Recycling.

Abstract The total amount of water that precipitates on large continental regions is supplied by two mechanisms: 1) advection from the surrounding areas external to the region and 2) evaporation and transpiration from the land surface within the region. The latter supply mechanism is tantamount to the recycling of precipitation over the continental area. The degree to which regional precipitation is supplied by recycled moisture is a potentially significant climate feedback mechanism and land surface-atmosphere interaction, which may contribute to the persistence and intensification of droughts. Gridded data on observed wind and humidity in the global atmosphere are used to determine the convergence of atmospheric water vapor over continental regions. A simplified model of the atmospheric moisture over continents and simultaneous estimates of regional precipitation are employed to estimate, for several large continental regions, the fraction of precipitation that is locally derived. The results indicate t.
Application of the notion of Φ-object to the study of p-class groups and p-ramified torsion groups of abelian extensions

We revisit, in an elementary way, the classical statement of various “Main Conjectures” for p-class groups HK and p-ramified torsion groups TK of abelian fields K, in the non semisimple case p | [K : Q]. The classical “algebraic” definition of the p-adic isotopic components, H alg K,φ, used in the literature, is inappropriate with respect to analytical formulas. For that reason we have introduced, in the 1970’s, an “arithmetic” definition, H ar K,φ, in perfect correspondence with all analytical formulas and giving a natural “Main Conjecture”, still unproved for real fields in the non semi-simple case. The two notions coincide for relative class groups H − K and groups TK since, in p-extensions, transfer maps are injective for these groups but not necessarily for real class groups. Numerical evidence of the gap between the two notions is given (Examples A.2.2, A.2.3) and PARI calculations corroborate that the true Real Main Conjecture for K writes on the form #H ar K,φ = #(EK/ÊK FK)φ, in terms of units EK , ÊK (units of the strict subfields) and FK (Leopoldt’s cyclotomic units). A recent approach, conjecturing the capitulation of HK in some auxiliary cyclotomic extensions K(μl), proves the difficult real case.
Strain accumulation in the New Madrid and Wabash Valley seismic zones from 14 years of continuous GPS observation

The mechanical behavior—and hence earthquake potential—of faults in continental interiors is an issue of critical importance for the resultant seismic hazard, but no consensus has yet been reached on this controversial topic. The debate has focused on the central and eastern United States, in particular, the New Madrid Seismic Zone, struck by four magnitude 7 or greater earthquakes in 1811–1812, and to a lesser extent the Wabash Valley Seismic Zone just to the north. A key aspect of this issue is the rate at which strain is currently accruing on those plate interior faults, a quantity that remains debated. Here we address this issue with an analysis of up to 14.6 years of continuous GPS data from a network of 200 sites in the central United States centered on the New Madrid and Wabash Valley seismic zones. We find that the high‐quality sites in these regions show motions that are consistently within the 95% confidence limit of zero deformation. These results place an upper bound on strain accrual on faults of 0.2 mm/yr and 0.6 mm/yr in the New Madrid and Wabash Valley Seismic Zones, respectively. For the New Madrid region, where a paleoseismic record is available for the past ∼5000 years, we argue that strain accrual—if any—does not permit the 500–900 year repeat time of paleo‐earthquakes observed in the Upper Mississippi Embayment. These results, together with increasing evidence for temporal clustering and spatial migration of earthquake sequences in continental interiors, indicate that either tectonic loading rates or fault properties vary with time in the New Madrid Seismic Zone and possibly plate wide.
Regional variations in wildfire susceptibility of land-cover types in Portugal: implications for landscape management to minimize fire hazard

Patterns of wildfire occurrence at the landscape level were characterised during the period 1990–94 in Portugal. Based on land-cover information within 5591 burned patches (larger than 5 ha) and in the surrounding landscape, selection ratio functions were used to measure fire preference or avoidance for different land-cover types in 12 regions of the country. Shrublands were the most fire-prone land cover, whereas annual crops, permanent crops and agro-forestry systems were the most avoided by fire. In terms of forest types, conifer plantations were more susceptible to fire than eucalyptus, and broadleaved forests were the least fire-prone. There were regional variations in land-cover susceptibility to fire, which may be explained by differences in climate, management, ignition patterns, firefighting strategies, and regional availability. A cluster analysis of regional variations in selection ratios for all land covers allowed the identification of three main geographical areas with similar fire selection patterns. These results can be used for planning landscape-scale fuel management in order to create landscapes with a lower fire hazard.
Crossing boundaries for environmental science and management: combining interdisciplinary, interorganizational and international collaboration

SUMMARY Literature on environmental science and management endorses crossing boundaries between disciplines, types of organizations and countries for environmental conservation. A literature review on interdisciplinarity, interorganizational networks and international cooperation highlights their justifying rationales and strategic practices. Crossing boundaries implies substantial challenges to managing collaboration itself, notably politics and uncertainty. Challenges to collaboration become compounded when crossing multiple boundaries simultaneously, here illustrated using the case of three projects in the south-western Amazon. Strategic practices such as net brokering and organizational courtships are highly important when crossing multiple boundaries. There are important commonalities in strategic practices for crossing different boundaries, such as recognizing grievances to manage politics, constituting functional redundancies in networks to manage uncertainty and non-aligned collaboration to manage both difficulties.
Zircon U-Pb Chronology of the Nyingtri Group, Southern Lhasa Terrane, Tibetan Plateau: Implications for Grenvillian and Pan-African Provenance and Mesozoic-Cenozoic Metamorphism

The Nyingtri Group of the Lhasa terrane in southern Tibet consists dominantly of metasedimentary rocks and orthogneiss. These rocks have a similar mineral paragenesis of plagioclase + K-feldspar + biotite + quartz ± sillimanite ± garnet ± staurolite ± muscovite ± amphibole, indicating amphibolite-facies metamorphic conditions. Inherited detrital zircons from the metasedimentary rocks show magmatic features and yield widely variable 206Pb/238U ages ranging from 3300 to 50 Ma. The data define two prominent age populations, 1200–1000 and 600–500 Ma, indicating that the source of the Nyingtri Group preserves the records of both Grenville and Pan-African magmatic-thermal events. Inherited magmatic zircon cores from the orthogneiss yield a crystallization age of 496 Ma, limiting the depositional age of the metasedimentary sequence to Cambrian or older. Overgrowth rims on the detrital zircons from one metasedimentary rock yield a metamorphic age of 32 Ma. On the basis of these results, together with the regional comparison, we infer that the Nyingtri Group was formed during or before the Cambrian, with a potential provenance from the Pinjarra Orogen of Western Australia–East Antarctica. This rock group, together with the Tethyan Himalayan Sedimentary Sequence, represents an early Paleozoic sedimentary cover of the northern margin of the Gondwana supercontinent that was intruded by Cambrian granites during the circum-Gondwana Andean-type orogeny. Along with published data, this study demonstrates that the Nyingtri Group was metamorphosed during Mesozoic and Cenozoic, as against the previous notion of a Precambrian metamorphic basement for the Lhasa terrane.
Time Domain Reflectometry Response to Lateral Soil Water Content Heterogeneities

Water-content heterogeneities can occur between the parallel rods of the time domain reflectometry (TDR) probe if TDR is used in cracked soils or in laboratory studies with probes oriented in a variety of directions. The accuracy of water-content measurements using TDR under such heterogeneous conditions was investigated in a series of laboratory experiments. Two cases were studied: (i) one TDR rod in dry soil and the other in wet soil; and (ii) an artificial soil crack filled with water or air between the two TDR rods. In Case 1, TDR readings were heavily biased toward the water content of the dry soil. This effect occurs because the electromagnetic wave (EMW) reaches the end of the waveguide quicker in dry than in wet material. Because the time delay of the earliest reflection signal is read from the TDR, the travel time of the dry material is measured. In Case 2, the air-filled crack between the waveguide rods had only a small effect on measured water content when the soil was dry; however, water-content measurements were reduced by as much as 46% in wetter soils. The effect of water-filled cracks was small in both dry and wet soils. The effect of soil cracks is explained by a static capacitance model. Results from the experiments do not contradict previous work that demonstrated that TDR measures the average water content of heterogeneous layers oriented perpendicular to the TDR probe axis. In the two cases examined here, knowledge of the orientation of soil water heterogeneities relative to the TDR waveguide rods is necessary for correct data interpretation.
Effects of polar ice on the Earth's rotation and gravitational potential

SUMMARY Gridded values of net surface accumulation rates for the Antarctic and Greenland ice sheets are used to estimate the contributions these two regions make to the Earth's gravity and rotation. The ice discharge from both ice sheets is adjusted so that the estimates of sea-level contribution from both ice sheets fall within limits for present mass balance suggested by the Committee on Glaciology (1985). These sea-level contributions are, for Antarctica, −0.6 ± 0.6 mm yr,minus;1, and for Greenland, -0.1 ± 0.4 mm yr−1. The contributions to the low-order zonal harmonic coefficients of the Earth's gravitational potential from Antarctica are found to be between two and 10 times larger than the uncertainties of the zonal harmonics derived from satellite solutions. For Greenland, the coefficients are within an order of magnitude of the uncertainties of the satellite solutions. These results are not definitive. They are presented to demonstrate that the ice sheets contribute to gravity in amounts that are within the limits of detection by satellite ranging methods. The secular trends in the X and Y components of observed polar-motion excitation agree in magnitude and sign with the Antarctic contributions, for a model where the interior regions on the ice sheet undergo a net thinning and the coastal regions thicken. For this model, the boundary between the interior and coastal regions is set at the contour of constant accumulation of 0.28 m yr-1 water equivalent, and the magnitude of the thickness change is set equal to the local accumulation rate. The contributions from Greenland to the secular trends in polar-motion excitation and length-of-day are either smaller than or of opposite sign to the observed effects and are found to be smaller than those of Antarctica. The limited information on mass balance and ice discharge including calving of ice and refreezing of melt-water for both ice sheets and the lack of measured data for land-based water storage makes the results presented here highly speculative. In addition, the inelastic response of the Earth to changes in surface mass loading is not considered here. This delayed response can reduce the magnitude of the effects presented here by as much as 15 per cent if the loading is a linear trend spanning 100 yr and the correction can be larger for longer histories of loading, see Wahr et al.(1992). These results suggest very approximate upper and lower limits for both inter-annual and secular contributions of polar-ice mass balance to Earth rotation and gravity. These limits are useful where they fall within the range of detectability using satellites.
HYDRAULIC PROPERTIES OF A SANDY SOIL AT LOW WATER CONTENTS

The soil water characteristic and hydraulic conductivity curves of Shonai sand dune soil were measured from saturation to 25-MPa matric suction. The hydraulic conductivity was measured using a steady-state flux control and an instantaneous profile method in two different matric suction ranges. The determined hydraulic conductivity varies from 10−2 to 10−13 cm/s, with change in volumetric water content from saturation to 1.0%. An empirical equation relating hydraulic conductivity with volumetric water content was developed, which fits the measured data very well. The vapor and the liquid components of hydraulic conductivity were estimated. The estimated vapor component exceeds the liquid component below 2.1% (5-MPa matric suction) water content. The measured values of hydraulic conductivity were used to test the Mualem and the Burdine predictive equations. Both equations estimate the hydraulic conductivity fairly well at water contents higher than 18%, but overestimate the conductivity at medium water contents from 5 to 18%
Reassessment of the source of the 1976 Friuli, NE Italy, earthquake sequence from the joint inversion of high-precision levelling and triangulation data

SUMMARY In this study, we revisit the mechanism of the 1976 Friuli (NE Italy) earthquake sequence (main shocks Mw 6.4, 5.9 and 6.0). We present a new source model that simultaneously fits all the available geodetic measurements of the observed deformation. We integrate triangulation measurements, which have never been previously used in the source modelling of this sequence, with high-precision levelling that covers the epicentral area. We adopt a mixed linear/non-linear optimization scheme, in which we iteratively search for the best-fitting solution by performing several linear slip inversions while varying fault location using a grid search method. Our preferred solution consists of a shallow north-dipping fault plane with assumed azimuth of 282° and accommodating a reverse dextral slip of about 1 m. The estimated geodetic moment is 6.6 × 1018 Nm (Mw 6.5), in agreement with seismological estimates. Yet, our preferred model shows that the geodetic solution is consistent with the activation of a single fault system during the entire sequence, the surface expression of which could be associated with the Buia blind thrust, supporting the hypothesis that the main activity of the Eastern Alps occurs close to the relief margin, as observed in other mountain belts. The retrieved slip pattern consists of a main coseismic patch located 3–5 km depth, in good agreement with the distribution of the main shocks. Additional slip is required in the shallower portions of the fault to reproduce the local uplift observed in the region characterized by Quaternary active folding. We tentatively interpret this patch as postseismic deformation (afterslip) occurring at the edge of the main coseismic patch. Finally, our rupture plane spatially correlates with the area of the locked fault determined from interseismic measurements, supporting the hypothesis that interseismic slip on the creeping dislocation causes strain to accumulate on the shallow (above ∼10 km depth) locked section. Assuming that all the long-term accommodation between Adria and Eurasia is seismically released, a time span of 500–700 years of strain-accumulating plate motion would result in a 1976-like earthquake.
Miocene evolution of atmospheric carbon dioxide

Changes in pCO2 or ocean circulation are generally invoked to explain warm early Miocene climates and a rapid East Antarctic ice sheet (EAIS) expansion in the middle Miocene. This study reconstructs late Oligocene to late Miocene pCO2 from ep values based on carbon isotopic analyses of diunsaturated alkenones and planktonic foraminifera from Deep Sea Drilling Project sites 588 and 608 and Ocean Drilling Program site 730. Our results indicate that highest pCO2 occurred during the latest Oligocene (∼350 ppmv) but decreased rapidly at ∼25 Ma. The early and middle Miocene was characterized by low pCO2 (260–190 ppmv). Lower intervals of pCO2 correspond to inferred organic carbon burial events and glacial episodes with the lowest concentrations occurring during the middle Miocene. There is no evidence for either high pCO2 during the late early Miocene climatic optimum or a sharp pCO2 decrease associated with EAIS growth. Paradoxically, pCO2 increased following EAIS growth and obtained preindustrial levels by ∼10 Ma. Although we emphasize an oceanographic control on Miocene climate, low pCO2 could have primed the climate system to respond sensitively to changes in heat and vapor transport.