Miracle-dz/UniFAR-FTUs huggingface dataset:
Seismic reflection coefficients of faults at low frequencies: a model study

We use linear slip theory to evaluate seismic reflections at non‐welded interfaces, such as faults or fractures, sandwiched between general anisotropic media and show that at low frequencies the real parts of the reflection coefficients can be approximated by the responses of equivalent welded interfaces, whereas the imaginary parts can be related directly to the interface compliances. The imaginary parts of low frequency seismic reflection coefficients at fault zones can be used to estimate the interface compliances, which can be related to fault properties upon using a fault model. At normal incidence the expressions uncouple and the complex‐valued P‐wave reflection coefficient can be related linearly to the normal compliance. As the normal compliance is highly sensitive to the infill of the interface, it can be used for gas/fluid identification in the fault plane. Alternatively, the tangential compliance of a fault can be estimated from the complex‐valued S‐wave reflection coefficient. The tangential compliance can provide information on the crack density in a fault zone. Coupling compliances can be identified and quantified by the observation of PS conversion at normal incidence, with a comparable linear relationship.
Is the World Ocean Warming? Upper-Ocean Temperature Trends: 1950–2000

Abstract Subsurface temperature trends in the better-sampled parts of the World Ocean are reported. Where there are sufficient observations for this analysis, there is large spatial variability of 51-yr trends in the upper ocean, with some regions showing cooling in excess of 3°C, and others warming of similar magnitude. Some 95% of the ocean area analyzed has both cooled and warmed over 20-yr subsets of this period. There is much space and time variability of 20-yr running trend estimates, indicating that trends over a decade or two may not be representative of longer-term trends. Results are based on sorting individual observations in World Ocean Database 2001 into 1° × 1° and 2° × 2° bins. Only bins with at least five observations per decade for four of the five decades since 1950 are used. Much of the World Ocean cannot be examined from this perspective. The 51-yr trends significant at the 90% level are given particular attention. Results are presented for depths of 100, 300, and 500 m. The patterns o.
Global Modes of Sea Surface Temperature Variability in Relation to Regional Climate Indices

AbstractA century-long EOF analysis of global sea surface temperature (SST) was carried out and the first six modes, independent by construction, were found to be associated with well-known regional climate phenomena: the El Nino–Southern Oscillation (ENSO), the Atlantic multidecadal oscillation (AMO), the Pacific decadal oscillation (PDO), the North Pacific Gyre Oscillation (NPGO), El Nino Modoki, and the Atlantic El Nino. Four of the six global modes are dominated by Pacific changes, the other two (M2 and M6) being associated with the AMO and Atlantic El Nino, respectively. The principal component time series of the ENSO (M1) and North Pacific (M3) modes are coherent at time scales >10 yr, and their interaction results in the traditional PDO pattern and the dominant mode of Pacific multidecadal variability. The M3 and PDO time series are well correlated, but the EOFs have different spatial patterns. The fourth mode (M4) has been strengthening since the 1950s and is related to the NPGO but also to El Nin.
CAVITY EXPANSION TESTS IN A HOLLOW CYLINDER CELL

This paper presents the use of the hollow cylinder cell in investigating, under laboratory controlled conditions, the response of saturated, consolidated fine grained soils to a cavity expansion. The hollow cylinder cell concept developed originally by Kirkpatrick was adapted to perform cylindrical cavity tests in annular soil specimens with measurement of the excess pore-water pressure generated in the surrounding soil. This modified hollow cylinder cell was also used to study the consolidation of the soil around an expanding cylindrical cavity under a constant cavity pressure and to evaluate available procedures, which can be used to obtain the soil hydraulic conductivity. The equipment, testing procedures, and analysis of both expansion and consolidation test results are discussed.
Multiplatform observations of boundary layer structure in the outer rainbands of landfalling typhoons

This paper analyzes data collected from a new set of observational platforms in the coastal area of China, which consist of a mobile observation system, meteorological tower, automatic weather station, and Doppler radars, to investigate the mean and turbulent boundary layer structure and evolution during the landfall of typhoons. An example of these data is provided from Typhoon Morakot (2009). Vertical profiles of wind velocities and thermodynamic parameters from the observed data allow us to identify different boundary layer structures during and after landfall. These structures, sampled in regions of the outer core, are stratified into periods where convection is occurring (termed “convective”) and periods where convection has recently (<2 h) occurred (termed “postconvective”). Data analyses show that the thermodynamic mixed‐layer depth and inflow layer depth are higher during the convective period than the postconvective period. The mixed‐layer depth is found to be within the strong inflow layer, but the height of the maximum tangential wind speed is above the inflow layer during both periods, contrary to recent observational studies of the boundary‐layer structure of tropical cyclones over water. High‐frequency wind data show that momentum flux, turbulent kinetic energy (TKE) and integral length scales of wind velocities are all much larger during the convective period than the postconvective period. The results suggest that convective downdrafts may play an important role in modulating turbulent flux, TKE, vertical mixing, and boundary layer recovery processes.
THE TANCO PEGMATITE AT BERNIC LAKE, MANITOBA. XVI. ZONAL AND BULK COMPOSITIONS AND THEIR PETROGENETIC SIGNIFICANCE

The Tanco pegmatite deposit at Bernic Lake, in southeastern Manitoba, is a virtually completely hidden, essentially undeformed, subhorizontal, bilobate, saddle-shaped body ~1520 m long, 1060 m wide and up to ~100 m thick. The highly fractionated pegmatite of the LCT family, rare-element class, petalite subtype, consists of nine internal zones. The outer zones are concentric, whereas the layered inner zones are segmented and locally complex in shape. A 3D computer model representation of the pegmatite assisted in calculation of volumes and compositions of individual zones and of the whole pegmatite, based on 102 km of 1355 drill-hole intersections, underground observations, measured and estimated mineral modes of the zones, zone-specific compositions and densities of minerals, and ore grades. The early outer zones tend to show granitic modes, but the inner zones strongly deviate in proportions of feldspars, or by high enrichment in lithium minerals, and some of the zones are virtually monomineralic. The bulk mode of Tanco is granitic, except ~9 vol.% petalite (including spodumene + quartz pseudomorphs). Despite also being economically significant for Cs, Ta and Li, the pegmatite contains less than 1 vol.% of any other non-micaceous minerals, and less than 0.1% of most of them. The bulk chemical composition closely reflects the modal relationships: it is peraluminous, and granitic, with prominent enrichment in Li, Rb, Cs and F, moderate contents of Tl, Be, B, Ga, Sn, Nb and Ta, and remarkable depletion in Fe, Mn, Mg, Ca, Ba, Sc, Ti and Zr. A very high degree of fractionation is shown for the bulk pegmatite by the values K/Rb 4.7, K/Cs 9.3, Rb/Cs 2.0, Rb/Tl 137, Fe/Mn 0.63, Mg/Li 0.02, Al/Ga 917, Zr/Hf 2.6, Zr/Sn 0.21 and Nb/Ta 0.19. Zonal and bulk chemical composition is in rough agreement with the experimental thermal trough in the system Ab + Qtz + Ecr at 2 kbar P(H2O), but shifted toward the Ab apex by elevated B, P and F, and by the voluminous wall-zone. The composition of the wall zone (20) is remarkably similar to that of bulk Tanco, except for the elevated contents of rare elements in the latter that are concentrated in the intermediate and inner zones. In turn, zone (20) is very close to the composition of nearby, somewhat less fractionated peraluminous leucogranites that are parental to local genetically related pegmatite groups. The wall zone (20), which composes 44 vol.% of Tanco, represents by analogy a petrogenetic link between an undisclosed parent leucogranite and the Tanco deposit. These relationships document derivation of the Tanco pegmatite and its analogues elsewhere by igneous differentiation from a fertile leucogranitic magma.
The strongest desert dust intrusion mixed with smoke over the Iberian Peninsula registered with Sun photometry

[1] We present the analysis of the strongest North African desert dust (DD) intrusion that occurred over the Iberian Peninsula (IP) during the last decade, as registered by modern remote sensing techniques like Sun photometry. This event took place from 22 July to 3 August 2004. The most relevant features of this exceptional event, originated over the Saharan desert, were its great intensity and duration. We focus on the columnar aerosol properties measured by the AERONET-Cimel photometers at El Arenosillo (southwest) and Palencia (north-center) stations. Aerosol optical depth (AOD) reached a maximum of 2.7 at El Arenosillo during 22 July and 1.3 at Palencia on 23 July, with the Ansgtrom exponent values near zero during the AOD peaks. In addition, PM10 concentration levels are also reported at various sites of the IP in order to establish the impact of this intrusion, reaching daily values as high as 200 μg/m 3 and peaks near 600 μg/m 3 in an hourly basis. The interest of this special event is increased because of the mixing with smoke particles from concurrent forest fires in the IP. Features of the columnar volume particle size distribution and derived microphysical parameters, the single scattering albedo, and a reliable estimation of the radiative forcing under these extreme conditions are also reported. Complementary information, as air mass back trajectories, synoptic charts, images, and AOD maps of satellite sensors (SeaWIFS, MODIS) together with NAAPS prognostic model, is used in the analysis in order to draw a detailed scenario of this dust-smoke event over the IP.
Characterization of Bacteriogenic Iron Oxide Deposits from Axial Volcano, Juan de Fuca Ridge, Northeast Pacific Ocean

Iron oxides from the caldera of Axial Volcano, a site of hydrothermal vent activity along the Juan de Fuca Ridge, are characterized by abundant bacterial structures that closely resemble the sheaths of Leptothrix ochracea , the stalks of Gallionella ferruginea , and the filaments of a novel iron oxidizing PV-1 strain. These bacteria are commonly associated with iron-oxide precipitates and are proposed to play two causal roles in the formation of iron oxides at Axial Volcano. First, by increasing the rate of Fe 2+ oxidation, and second, by lowering the concentration of Fe 3+ required for precipitation by providing a reactive surface for heterogeneous nucleation. Rapid rates of oxidation and precipitation caused by the bacteria likely contribute to the poorly ordered nature of the iron oxides, determined to be primarily 2-line ferrihydrite, and in one case, poorly ordered goethite. The iron-oxide precipitates consist dominantly of iron, silicon (mostly diatoms), and organic carbon with a suite of sorbed trace metals. The high metal uptake affinity of these poorly ordered iron oxides may be important in the global cycling of trace elements throughout the world's oceans. Additionally, iron oxides precipitating on the surface of bacteria can preserve individual cells as microfossils making bacteriogenic iron oxides ideal proxies for paleoenvironmental and astrobiological studies.
Burning for zebu: The complexity of deforestation issues in western Madagascar

This study takes a human-geographical approach to examine the crucial problem of deforestation in Madagascar. Current land-use practices on the west coast threaten the survival of the dry primary forest, which exists in a delicate ecological balance under a climate bordering on aridity. A shifting-agriculture system, encouraged by government policy aimed at expanding crop cultivation, is the major factor contributing to the reduction of forested land. The forest is set on fire and the burns used to cultivate maize. After three years, yields drop dramatically, and people search for new areas of forest to clear. The practice is likely to lead to the complete disappearance of the western forests if nothing is done to change the current situation. The main practitioners are migrant Tandroy from the south of Madagascar. They migrate for reasons related to widespread local poverty and cultural practices linked to their reverence for cattle. They destroy the forests less for immediate survival than in order to gain possession of as many zebu as possible, which for them is the only way to acquire social status. Because Androy, their home region, is too poor to permit such acquisitions, migration to and deforestation of the western forest becomes an attractive alternative. The sale of maize to private exporters at a high price provides profits that can be used to buy cattle. This cultivation contributes little to food production in Madagascar, and the Tandroy , motivated by cultural considerations, stand at the base of a chain of exploitation that ends overseas. Agricultural and conservation policies in Madagascar currently do not address cultural and economic complexities such as these.
A Central-U.S. Summer Extreme Dew-Point Climatology (1949-2000)

Daily average dew points (DADPs) were examined at 68 central-U.S. weather stations from 1949 to 2000 to identify temporal trends in the occurrence of summer (June—August) extreme surface dew-point days (DADP ≥22°C). Data homogeneity testing revealed that changes in equipment, station location, and instrument height, in addition to calculated DADPs based on available hourly data caused very few statistically significant changes in the data. Temporal patterns based on four 13-yr. periods indicated that much of the Midwest experienced a consistent increase in extreme DADPs through time while those along the Gulf Coast remained generally unchanged. Using accumulated DADP departure from the median graphs, the 52-yr. record was separated into two periods. A comparison of the mean frequency from an earlier (1949-1976) to later (1977-2000) period indicated that the greatest percent increases also occurred in the Midwest. Smaller increases to the south of this area suggest that these increases are not primarily linked to advection from the Gulf of Mexico, rather they are related to changes in a regional moisture source. This moisture source appears to be related to enhanced levels of evapotranspiration from corn and soybean crops, which have experienced a near doubling in total acreage from 1950 to 2000.
Analysis of changing pan evaporation in the arid region of Northwest China

Decreases in pan evaporation (Ep) over the last decades have been reported in many regions of the world. In this study, we investigated Ep dynamics in the hyper‐arid region of China during the period 1958–2010 using a generic physical model based on long‐term meteorological data collected at 81 ground‐based meteorological stations. We also quantified the contribution of climatic factors to the Ep change using partial derivatives. We found that Ep in the region exhibited an obvious decreasing trend until early 1990s (1993), at a rate of −6.0 mm yr−2. However, the downward trend reversed in 1993, and the rate of increase after that was 10.7 mm yr−2. We also assessed the sensitivity of rates of evaporative demand to changes in aerodynamic and radiative components, and found that pan evaporation could be mostly attributed to changes in the aerodynamic component, with some regional contributions from solar irradiance. Observed near‐surface wind speed is the primary contributor to the decline of pan evaporation during 1958–1993, while wind speed (WS) and vapor pressure deficit (VPD) were both major contributors to the increase of pan evaporation after 1993.
Freedom to Learn: A Study of the Experiences of Secondary School Teachers and Students in a Geography Field Trip

This study is a qualitative case study of a geography field trip of Secondary Four (Year 10) students in a Hong Kong school. It conceives fieldwork as an experiential activity in which an understanding of the experiences of teachers and students in their contexts is important. The results revealed that the students' intent before the trip and their learning experiences after the trip were much richer than their teachers had intended. Despite some students' negative experiences of previous field trips, there was a universally strong desire to escape from their perceived boredom and constraints of the classroom. Field trips were cherished for their rarity and freedom, and the field sites were sought for their novelty. The study has revealed the relative freedom of the field as a learning environment in which the students were more proactive and teacher-student rapport improved. Besides deepening their understanding of what they had previously learned in class, some students were able to see things in new pe.
Claying and deep ripping can increase crop yields and profits on water repellent sands with marginal fertility in southern Western Australia

Sandplain soils on the south coast of Western Australia have multiple limitations to crop production that include water repellence, low water and nutrient retention, subsoil acidity, and high soil strength. Crops on sandplain soils achieve, on average, almost 85% of their rainfall-limited yield potential; however, where there are multiple limitations the corresponding value is often 3–6%) had cumulative discounted cash returns $AU100–200/ha higher than the unclayed ‘control’ treatment and $300/ha higher than the lowest clay rates. For most of the clay treatments, deep ripping increased discounted returns between 2005 and 2007 by $80–120/ha.
Sea surface temperature (AVHRR, MODIS) and ocean colour (MODIS) seasonal and interannual variability in the Macaronesian islands of Azores, Madeira, and Canaries

Within the framework of ORPAM (03/MAC/4.2/A2) project, five years of AVHRR Sea Surface Temperature (SST) (in °C) (2001-2006) (HAZO station, Azores) and of MODIS Ocean Colour (OC) (chlorophyll a in mg m-3) and SST (2002- 2007) data (NASA/GSFC), allowed the establishment and comparison of the mean surface temporal variability among the Azores, Madeira, and Canaries regions. Results show strong and similar seasonal SST variability patterns with average values ranging between 15°C (winter) and 27°C (summer). Largest SST differences are observed during wintertime (Azores/Canaries-lowest/highest values, respectively). Interannual SST variability shows no defined patterns among the three regions. Ocean Colour seasonal variability varies inversely with SST. In the Azores, spring blooms dominate, followed sometimes by smaller autumn ones. In Madeira, spring blooms dominate. In Canaries, OC means are highest during February and March. Interannual OC variability shows the largest variation in Canaries (summertime). These results suggest strong latitudinal gradient effects. Canaries waters are generally warmest, followed by Madeira, and Azores. Highest OC averages are found in the Azores and Canaries regions. In the latter case, this most likely reflects e.g.: the contribution of the African coastal upwelling; OC algorithms failure in Case 2 waters; and winter mixing processes in the region.
Connections between stratospheric ozone and climate: Radiative forcing, climate variability, and change

Abstract Quantifying the combined effects of ozone depletion and changes in other greenhouse gases and radiatively and chemically active atmospheric constituents is of great importance to human welfare. Achieving this goal requires evaluating the impact of stratospheric ozone depletion and its recovery on the tropospheric climate as well as elucidating the effects of climate change on the evolution of ozone itself. This, in turn, requires the understanding and quantification of the long‐term sensitivity of the climate system to significant perturbations in the radiation budget of the atmosphere associated with human activities. Detecting and quantifying such effects also requires a quantitative understanding of the role of natural events, such as volcanoes and solar variability, on the composition and evolution of the atmosphere and ultimately of the effects of such events on the climate change signal throughout the active atmosphere and at the surface. With the advent of climate modelling as a key tool for studying and predicting the evolution of the climate system, the linked concepts of radiative forcing and climate sensitivity have come into wide use as a means to understand and quantify key aspects of modelling results. These concepts are reviewed and their relevance to understanding and quantifying the radiative impact of ozone and ozone depleting substances on the radiative forcing of the climate system are discussed. Recent observational, theoretical, and modelling studies have revealed many new features of stratosphere‐troposphere coupling that are relevant to understanding the role of stratospheric processes in climate variability and change. Aspects of these studies are reviewed briefly.
Lava flow layer‐East Pacific Rise

A multichannel seismic reflection profile across the East Pacific Rise near 9°N reveals an approximately 400 m thick layer at the top of the oceanic crust with seismic velocity of about 2.8 km/s at the Rise crest. This velocity increases to about 3.8 km/s, 210 km east of the Rise crest. These low velocities suggest that this layer is probably a porous lava flow layer (layer 2A of seismic refraction studies) generated by volcanic activity at the spreading center. Reflections from the base of the layer imply a relatively sharp transition between the lava flows and the underlying layer (presumably a sheeted dike complex). The underlying layer is a zone about 1.4 km thick (with velocity about 5.7 km/s) whose base may coincide with the top of a low velocity magma chamber from which the crust develops.
The freeze-thaw weathering regime at a section of the Niagara escarpment on the Bruce Peninsula, Southern Ontario, Canada

The bedrock freeze-thaw and moisture regimes at an actively eroding site on the Niagara Escarpment, Bruce Peninsula, southern Ontario, were monitored between December 1983 and April 1984, and the results compared with amounts of debris collected in an adjacent rock trap. Frost wedging in pre-existing rock fissures is the primary mechanism responsible for the observed rockfall events; hydration effects are negligible. Debris production was more closely related to the duration of the freezing leg of the freeze-thaw cycle than to intensity or to cycle frequency. Release also coincided with periods of high pore saturation (> 60 per cent) and the seepage of water from cracks and fissures. Fewer freeze-thaw cycles were recorded in the air than at 1 and 3.5 cm in the bedrock. The number of cycles that could be declared geomorphologically effective according to established temperature criteria was normally less than half the total number of freeze-thaw cycles recorded in both air and bedrock. Under the current temperature regime at the field site, few effective cycles are capable of penetrating more than 5 cm into the free face.