Miracle-dz/UniFAR-FTUs huggingface dataset:
Seismic-frequency loss mechanisms: Direct observation

Abstract Direct measurement of seismic attenuation (1/Q) and velocity dispersion in the laboratory point to several independent loss mechanisms. A forced-deformation technique allows measurement at seismic frequencies and amplitudes. Fluid motion is the primary mechanism in porous, permeable clastics. In shales, bulk-fluid motion is inhibited, and clay-particle interaction with bound water might dominate. Another mechanism usually not considered is losses in the fluid phase alone. Heavy, viscous fluids show bulk losses independent of a rock matrix. All these loss mechanisms are frequency dependent, so observations of 1/Q made at seismic frequencies usually will not agree with ultrasonic data. Attenuation and velocity dispersion are coupled processes, and validity of the frequency-dependent 1/Q values can be checked by comparison with observed velocity dispersion over a broad frequency range.
Tectonic implications of granite cobbles from the mid-Cretaceous Pororari Group, southwest Nelson, New Zealand

Abstract Petrographic and geochemical data confirm the source of granitic detritus in the Hawks Crag Breccia of the lower Buller Gorge to be the Early Cretaceous Buckland, Blackwater, and Steele Plutons, presently disposed to the south and southwest. Detritus in the Hawks Crag Breccia in the Fox River and Bullock Creek may also be derived from the Buckland Pluton, but the provenance of the granitic detritus in this formation in the Pike Stream remains unclear. However, granitic clasts in the Ohika Formation were derived from Paleozoic granites of the Karamea Suite, of which potential source plutons are presently widely distributed to the WNW (Orowaiti River), the north (Britannia Pluton), and to the east (Dunphy Granite). Clasts derived from the deformed basement of the Paparoa Metamorphic Core Complex first appear in the upper part of the Ohika Formation, indicating initial unroofing of the complex at that time. The indicated source directions are consistent with a northwest-southeast trend for the two d.
A Geography of Appalachian Identity

Definitions of the Appalachian region vary considerably. In this paper we develop a theoretically grounded and empirically based understanding of Appalachia by focusing on the social process of regional identity. Our measure of Appalachian identity is based on the relative number of businesses in a city that include the word "Appalachian" in their name. From this analysis, we find that the core area of Appalachian identity lies in Eastern Tennessee, Western North Carolina, Eastern Kentucky, Southern West Virginia, and Southwestern Virginia. We also explore the predictors of Appalachian identity and determine that poverty level, percent Black, elevation, and population density predict Appalachian identity. This work should be of interest to social scientists concerned with the study of regional identity—both inside and outside of Appalachia.
Formation and export of dense shelf water from the Adélie Depression, East Antarctica

[1] Coastal polynyas in the Adelie Depression are an important source of Antarctic Bottom Water to the Australian-Antarctic Basin. We present time series (April 1998 to May 1999 and August 1999 to February 2000) of data from temperature-salinity sensors, in both the Adelie Depression and the known outflow region of the Adelie Sill, to describe the annual cycle of shelf water densities. From April through September, salinification beneath the polynya produces dense shelf waters. During September–October, shelf water densities in the depression peak at 27.94 kg m−3, and the cooling and freshening signature of Ice Shelf Water is observed north of Buchanan Bay. In November–December, shelf water densities decrease as intrusions of warm and relatively fresh modified Circumpolar Deep Water enter east of the Adelie Sill. From January–March the surface layer is conditioned by the cooling of the atmosphere, which overturns the upper water column. At the Adelie Sill, observed daily mean currents were approximately 10 cm s−1 with intense instantaneous currents greater than 50 cm s−1 at the sill depth. Using an idealized outflow region with a rectangular cross-sectional area (6 × 106 m2), we present the first estimates of shelf water export by potential density class. Assuming shelf water with a minimum density of 27.88 kg m−3 has sufficient negative buoyancy for downslope mixing and a fourfold volume increase (1:3 mixing ratio) from entrainment, the dense shelf water export of 0.1–0.5 Sv results in an annual average production of bottom water in this region of between 0.4 and 2.0 Sv. The wide range in bottom water estimate results from data limitations, and a narrowing of this range requires further mooring observations.
Precolumbian Settlements on Carriacou, West Indies

Abstract The first systematic archaeological investigation of Precolumbian sites on the island of Carriacou in the West Indies provides a rich source of information regarding Amerindian settlement in the southern Caribbean. Herein, we report results from an island-wide survey and subsequent excavation at two large village sites—Grand Bay and Sabazan—that provide evidence for an intensive late Ceramic Age occupation dating between CAL. A.D. 400–1200. Results from four seasons of excavation at Grand Bay and two at Sabazan indicate that inhabitants colonized the island later than larger nearby islands (although an earlier settlement is possible); were engaged in inter-island and South American interactions as evidenced through analysis of pottery, stylistic artifacts, and faunal remains; exploited a variety of marine and terrestrial foods, including several animals rarely found in the Antilles that were translocated to the island from elsewhere; and buried their dead in and around shell middens and, at least once, under a habitable structure.
Cover: Monitoring of invasive Tamarix distribution and effects of biological control with airborne hyperspectral remote sensing

G. L. ANDERSON*{, R. I. CARRUTHERS{, SHAOKUI GE§ and PENG GONG§ {USDA Agricultural Research Service, Northern Plains Area, 1500 North Central Avenue, Sidney, Montana 59270-4202, USA {USDA Agricultural Research Service, Exotic and Invasive Weeds Research Unit, 800 Buchanan Street, Albany, California 94710, USA §Center for Assessment and Monitoring of Forest and Environmental Resources (CAMFER), 151 Hilgard Hall, University of California, California 94720-3110, USA
Gelifluction: Observations from Large-Scale Laboratory Simulations

Despite extensive field studies, progress in understanding gelifluction processes has been limited. Controlled laboratory simulation experiments offer an alternative and potentially extremely effective approach. Such an experiment is described here. It was conducted on a 12° slope formed of two natural soils, one a fine sandy silt derived from slate bedrock, the second a gravelly silty sand derived from mudstone bedrock. Continuous measurements were made of soil temperatures, porewater pressures, frost heave, thaw settlement, and downslope displacements of the soil surface over seven freeze/thaw cycles. Two-dimensional vectors of soil surface movements together with evidence from excavated displacement columns suggest that gelifluction occurred only during thaw consolidation of the upper parts of the soil profile; thawing of the deeper layers caused thaw consolidation but little downslope displacement. Cryogenic processes are shown to cause progressive decreases with depth in void ratio and moisture content and increases in undrained shear strength within the continuous soil matrix that separates ice lenses. Since self-weight stress levels are low, thawing leads to significant shear strain only in the softer, wetter near-surface soil layers.
Path histories and timescales in stratospheric transport: Analysis of an idealized model

Mean age and the age spectrum, transport diagnostics independent of photochemistry, have been put to good use diagnosing stratospheric circulation and evaluating models. These diagnostics reveal how long air took to reach a stratospheric location from the troposphere, but they provide no direct information about where the air traveled en route. I define a complement to the age spectrum to explore how stratospheric transport timescales are related to path histories. Just as one constructs the age spectrum by distributing components of an air parcel according to transit time since last tropospheric contact, one can distribute the components according to the maximum height achieved en route to the parcel. Combining the age spectrum and the “maximum path height” distribution, one has a “joint distribution” of transit time and maximum path height. These ideas are illustrated with an idealized model of stratospheric transport, as well as a general circulation model. Transport features in the idealized model that strongly affect mean age affect the distribution of maximum path heights relatively weakly, especially in midlatitudes. The mass fraction of an air parcel at r that passed above some specified height z above r is strongly constrained by the mass continuity of stratospheric regions and is only more weakly affected by the circulation. This represents a limit on the relationship between mean age and trace gases of predominantly upper stratospheric photochemistry.
Meteorological controls on ozone at an elevated eastern United States regional background monitoring site

To determine synoptic- and regional-scale meteorological controls on ozone upwind of the North Atlantic Ocean, we developed an ozone climatology for Big Meadows, Virginia. Three methodologies were employed to analyze the 6-year ozone data set (1989–1994) from this elevated, regional, background monitoring site. (1)A springtime case study showed that repeated dynamic processes associated with three consecutive cold-front passages were related to a cyclic pattern in ozone variation. Back-trajectory analysis suggests a stratospheric as well as anthropogenic influence on the enhanced ozone events. (2) Analyses of the meteorology and back trajectories associated with daytime ozone events above the 90th percentile and below the 10th percentile revealed strong contrasts in transport history. Enhanced events were strongly associated with dry high-pressure conditions and half were associated with descent through surface anticyclones. Conversely, the depleted-ozone trajectories were typically associated with low-pressure systems and were more likely to be associated with ascending or low-level flow than descending flow. (3) Back trajectories were grouped according to similar transport paths to try to explain ozone variance by airmass transport. In a previous study, segregation of ozone values by transport path explained a relatively large amount of the ozone variance at Bermuda. However, in our study, this approach explained only a small portion of the ozone variance. We attribute the differences in explained variance at the two sites to complex interactions between transport and photochemistry over the continent and a simplified transport regime over the western North Atlantic Ocean.
On the structure of the Southern Oscillation

Abstract A realistic oceanic general circulation model is forced with winds observed over the tropical Pacific between1967 and 1979. The structure of the simulated Southern Oscillation is strikingly different in the western andeastern sides of the basin, because the principal interannual zonal-wind fluctuations are confined to the westand are in the form of an equatorial jet. This causes thermocline displacements to have maxima offthe equatorin the west (where the curl of the wind is large) but on the equator in the east. Zonal phase propagation, bothon and offthe equator, is at different speeds in the west and east. The phase pattern is complex, and there is,on interannual time scale, no explicit evidence ofindividuai equatorial waves. These results lead to a modificationof the "delayed oscillator" mechanism originally proposed by Schopfand Suarez to explain a continual SouthernOscillation. The results also permit an evaluation of the various coupled ocean-atmosphere models that simulatethe Southern Osci.
Monitoring alluvial sand suspension by eddy correlation

Eddy correlation techniques are standard tools in micrometeorology and oceanography to measure momentum and contaminant transport across turbulent boundary layers. They can, in theory, be used to estimate the net vertical suspended sediment flux directly over different areas of an alluvial channel boundary, and thus disclose ongoing erosion/deposition patterns. The basic principles and main problems in applying the technique to alluvial suspension are first introduced. Results from a trial application of the method in a large sand bed river are then presented; the focus of the analysis is on the substantial (and surprising) contributions of multi-minute flow fluctuations to suspension work in the study environment. The data were collected in a 10 m deep channel of the Fraser River near Mission, British Columbia, Canada. Turbulent fluctuations of flow components streamwise and normal to the bed, along with the output of an optical suspended sediment sensor, were monitored over 7 h, 1 m above the bed. Flow velocities averaged 0·9 ms−1 and mean suspended sediment concentrations 500 mgl−1, at sensor level above 1–5 dm high dunes. Spectral analysis of the records reveals that approximately 30 per cent of the vertical suspended sand mixing across the sensor level (and roughly as much of the momentum exchange) was linked to gradual flow oscillations with periods between 1 and 13·6 min (underlying briefer, turbulent fluctuations). Extended periods of sediment-rich, slightly upward directed but slower mean flow alternated with periods of sediment-poor, slightly downward and faster mean flow; these slow fluctuations involved 10–20 cms−1 changes in 5 min average flow speed, 2–4· changes in vertical flow angle and 100 mgl−1 changes in mean sand concentration. To obtain accurate eddy-correlation estimates of the vertical suspension flux in the study conditions, hour-scale flow and turbidity records that include many of these multi-minute cycles appear to be necessary. The spectra of the Fraser River near-bed signals do not conspicuously differ in overall shape (in terms of low-frequency content and location of peak) from turbulent spectra encountered in some atmospheric boundary layers. Nonetheless, the long period fluctuations observed on the Fraser River may not be turbulent; rather they may reflect slowly evolving perturbations in the near-bed streamlines, caused by bedform translation or gradual fluctuation within the large-scale streamwise cells of the secondary flow.
East Australian marine abrasion surface

Abstract Almost one-third of the seabed off the coastline north and south of Sydney comprises a planated bedrock surface, evident from sidescan surveys over the inner continental shelf. In seismic records, this rock surface extends up to 23 km offshore from the sea cliffs along 300 km of the coast. The rock surface dips offshore to as much as 180 m below sea level, where it merges with a major unconformity in the shelf sediment wedge. The surface is eroded into Mesozoic and Palaeozic rocks and is heavily dissected by sediment-filled, palaeo-valley incision and structural jointing. The sediment-fills comprise sand wedges that thicken landwards to form beaches and estuarine flood-tide deltas, respectively, in smaller and larger palaeo-valleys incised to below present sea level. At the base of the cliffs, the planated surface is buried by shelf sand bodies up to 30 m thick in places. The seaward edge of the surface is everywhere buried by the onlapping continental-shelf sediment wedge. The contiguity of the abrasion surface with the unconformity in the shelf sediment wedge suggests that marine planation began in the Mid-Oligocene, indicating time-average rates of gross cliff retreat at about 1 mm a−1.
Spatial heterogeneity in photosynthesis‐irradiance parameters of phytoplankton across a cyclonic eddy in the Antarctic Divergence zone along 140°E

The latitudinal variation in the photosynthesis‐irradiance (P‐E) relationship of phytoplankton was investigated across a cyclonic eddy in the Antarctic Divergence zone along the 140°E longitude. Both the maximum photosynthetic rate (P*max) and maximum light utilization coefficient (α*) were lower at stations within the eddy as compared with those in the continental shelf‐slope area and the offshore area. The low‐density water mass of the eddy prevented the upward and horizontal supply of macronutrients and micronutrients, which likely resulted in a reduction of P*max and α*. In contrast, both P*max and α* were large and variable in the slope area, probably owing to a local stability resulting from the less‐saline surface water. The present study indicates the possibility that longitudinal variations in the latitudinal pattern of meanders, eddies, seasonal sea‐ice extent, and topographical conditions significantly influence the mesoscale variations in the P‐E parameters and primary production in the Southern Ocean.
Dynamical downscaling of ECMWF Ensemble seasonal forecasts over East Africa with RegCM3

[1] Dynamical downscaling of ECMWF ERA-interim reanalysis and an ensemble of May-start ECMWF seasonal hindcasts is performed with ICTP's regional climate model (RegCM3) over the horn of Africa for a ten year period. Using ERA-interim ‘perfect boundary’ conditions the regional model reproduced both the spatial and interannual variability of the region's rainfall and improved the global model's reproduction of year to year rainfall variability, capturing the teleconnection between ENSO and the region's precipitation pattern well. The ensembles of ECMWF seasonal hindcasts and the respective downscaled RegCM3 hindcast suite were then validated in terms of the seasonal climate and deterministic and probabilistic skill scores at a one to four month lead time. Both RegCM3 and ECMWF hindcasts reproduce the spatial and temporal rainfall variability well, but overestimate the mean and variability over the Arabian peninsula and misrepresent the teleconnection between ENSO and precipitation over the western Indian Ocean. The positive bias over the Arabian peninsula in RegCM3 and the teleconnection error between ENSO and precipitation anomalies over the western Indian Ocean are due to the propagation of errors from the driving GCMs to the regional model. Nevertheless, the probabilistic assessment (ROCS and RPSS) indicated that both ECMWF and RegCM3 have significant skill suggesting the potential utility of dynamical forecasts over the region. Comparing the skill of ECMWF and RegCM3 probabilistic hindcasts, ECMWF generally performs better on grid point by grid point comparison and at homogeneous zones over Ethiopia but RegCM3 outperforms when aggregated on a country scale and when compared against high resolution rain gauge data set.
A palaeoclimatic and palaeoceanographic record of the last 11 000 14C years from the Skagerrak-Kattegat, northeastern Atlantic margin

Marine sediments of about 116 m drilled onshore at Skagen near the northernmost tip of Jutland, Denmark, provides a continuous and detailed palaeoceanographic and palaeoenvironmental record of the last 11 000 14C years in the Skagerrak-Kattegat. The whole Younger Dryas was characterized by an arctic-subarctic environment where the North Jutland Current flows today, instead of being succeeded by a minor climate warming at about 10 600 BP as recorded in the southern Kattegat and in the areas strongly influenced by the Baltic Current and currents along the Swedish west coast. The changes in components of diatom assemblages, combined with previously published benthic foraminiferal data from the present core, reflect a two-step climatic warming and consequently environmental change during the transition from the Younger Dryas to the Preboreal. An abrupt warming of the sea surface waters took place at about 10 100 BP, which resulted from the inflow of warm Atlantic surface water. Summer sea-surface temperature rose about 8°C. It had a great influence on the surface water of the Skagerrak-Kattegat and shallow areas, but had only little effect on the bottom water in the deep parts of the region. Warming of bottom water occurred a few hundred years after the first warming, and is most likely simultaneous with the end of the Preboreal oscillation. A warm period at 7700-5100 BP is registered by diatom assemblages that resulted from the opening of the English Channel because of eustatic sea-level rise, and by larger influence of the Norwegian Coastal Current and currents along the Swedish west coast. A climate cooling was documented at about 5100 BP by acceleration of the South Jutland Current.
First macroflora data from La Val (Late Oligocene/Early Miocene), Estadilla (Huesca, Spain)

This paper reports a previously unknown leaf-flora from the Upper Oligocene/Lower Miocene of the Ebro Basin, NE Spain, a period with a relatively poor vascular-plant fossil record in Southern Europe. The presence of Acrostichum sp. is also important. This fern is extremely significant from the point of view of palaeoecology and the depositional environment. The macroflora appears to yield sufficient morphological characteristics to be identified at genus level, and sometimes at species level, although cuticles are not preserved. This article presents the first data obtained from the new outcrop at La Val; the following families have been identified: Pteridaceae, Dennstaedtiaceae, Equisetaceae, Pinaceae, Lauraceae, Hamamelidaceae, Betulaceae, Myricaceae and Salicaceae. The fossil plant assemblage is correlated with the Cadibona floristic complex (Mai, Tertiäre Vegetationsgeschichte Europas. Methoden und Ergebnisse, Gustav Fischer, Jena, 691 pp., 1995) and suggests a subtropical-to-warm temperate climate, rainy and wet, with a short dry season. The age of the assemblage is Late Oligocene/Early Miocene.
ACCURACY OF LAKE AND STREAM TEMPERATURES ESTIMATED FROM THERMAL INFRARED IMAGES 1

Emitted thermal infrared radiation (TIR, λ= 8 to 14 μm) can be used to measure surface water temperatures (top approximately 100 μm). This study evaluates the accuracy of stream (50 to 500 m wide) and lake (300 to 5,000 m wide) radiant temperatures (15 to 22°C) derived from airborne (MASTER, 5 to 15 m) and satellite (ASTER 90 m, Landsat ETM+ 60 m) TIR images. Applied atmospheric compensations changed water temperatures by −0.2 to +2.0°C. Atmospheric compensation depended primarily on atmospheric water vapor and temperature, sensor viewing geometry, and water temperature. Agreement between multiple TIR bands (MASTER ‐ 10 bands, ASTER ‐ 5 bands) provided an independent check on recovered temperatures. Compensations improved agreement between image and in situ surface temperatures (from 2.0 to 1.1°C average deviation); however, compensations did not improve agreement between river image temperatures and loggers installed at the stream bed (from 0.6 to 1.6°C average deviation). Analysis of field temperatures suggests that vertical thermal stratification may have caused a systematic difference between instream gage temperatures and corrected image temperatures. As a result, agreement between image temperatures and instream temperatures did not imply that accurate TIR temperatures were recovered. Based on these analyses, practical accuracies for corrected TIR lake and stream surface temperatures are around 1°C.
Apatite thermochronology in modern geology

Abstract Fission-track and (U–Th–Sm)/He thermochronology on apatites are radiometric dating methods that refer to thermal histories of rocks within the temperature range of 40°–125 °C. Their introduction into geological research contributed to the development of new concepts to interpreting time-temperature constraints and substantially improved the understanding of cooling processes within the uppermost crust. Present geological applications of apatite thermochronological methods include absolute dating of rocks and tectonic processes, investigation of denudation histories and long-term landscape evolution of various geological settings, and basin analysis.