bluuebunny/crossref_metadata_2025 huggingface dataset:
5D rotating black holes and the nAdS2/nCFT1 correspondence
Authors: Castro Alejandra , Larsen Finn , Papadimitriou Ioannis
Published: October 2018

Abstract

We study rotating black holes in five dimensions using the nAdS2/nCFT1correspondence. A consistent truncation of pure Einstein gravity (with a cosmological constant) in five dimensions to two dimensions gives a generalization of the Jackiw-Teitelboim theory that has two scalar fields: a dilaton and a squashing parameter that breaks spherical symmetry. The interplay between these two scalar fields is non trivial and leads to interesting new features. We study the holographic description of this theory and apply the results to the thermodynamics of the rotating black hole from a two dimensional point of view. This setup challenges notions of universality that have been advanced based on simpler models: we find that the mass gap of Kerr-AdS5corresponds to an undetermined effective coupling in the nAdS2/nCFT1theory which depends on ultraviolet data.
Preparation of transparent nanostructured N-doped TiO2 thin films by combination of sonochemical and CVD methods with visible light photocatalytic activity
Authors: Rasoulnezhad Hossein , Hosseinzadeh Ghader , Hosseinzadeh Reza , Ghasemian Naser
Published: October 2018

Pollution of water resources with pesticide compounds has raised serious environmental problems, and for photocatalytic degradation of these pollutants, thin film photocatalysts are preferred to colloidal ones due to the separation problem of colloidal nanoparticles. In this work, nanostructured TiO2 and N-doped TiO2 thin films with high transparency were deposited on glass and quartz substrates through sonochemical–chemical vapor deposition (CVD) method. The films prepared on glass and quartz substrates had nanocubic and nanospherical morphology, respectively. The presence of N atoms in the structure of TiO2 resulted in a decrease in the band gap energy of TiO2 and also in the reduction of photogenerated electron–hole recombination rate. Furthermore, the presence of N atoms induced the formation of Ti3+ species which can act as hole trapping centers. The prepared thin films were also used for the visible light photocatalytic degradation of paraoxon pesticide. According to these results among the prepared thin films, the N-doped TiO2 thin films have higher photocatalytic activity than pure TiO2 thin films. Moreover, in comparison with the thin films deposited on quartz substrate, the films on glass substrate have higher photocatalytic performance, which can be related to the special nanocubic morphology of these samples.
Co2+ substituted Mg–Cu–Zn ferrite: Evaluation of structural, magnetic, and electromagnetic properties
Authors: Thorat L. M. , Patil J. Y. , Nadargi D. Y. , Ghodake U. R. , Kambale R. C. , Suryavanshi S. S.
Published: October 2018

We report the synthesis of Co2+ substituted Mg–Cu–Zn ferrite via citrate gel combustion process and thereby its structural, transport, and magnetic properties for the use in electromagnetic energy absorption application. The polycrystalline ferrite system is investigated by interplay of stoichiometric composition with Mg0.25–x
Co
x
Cu0.25Zn0.5Fe2O4 (0 ⩽ x ⩽ 0.25). Structural investigations using X-ray diffraction (XRD) and selected area electron diffraction (SAED) reveal the formation of spinel structure with linear growth of lattice constant due to Co2+ substitution. The microstructural analysis (TEM and SEM) depicts the dense microstructure with the average grain size of 0.42–1.25 μm. The elemental analysis (EDS) confirms the elemental composition of the as-prepared ferrite with respect to the initial concentrations of the synthetic composition used. The observed variations in initial permeability (μ
i) and magnetic moment (n
B) are explained based on deviation in saturation magnetization (M
s), anisotropy constant (K
1), density values, and exchange interaction. The temperature dependence of DC resistivity confirms the semiconducting behavior of the as-prepared ferrite material, with an increase in the DC resistivity by an incorporation of cobalt. Furthermore, the effects of adding Co2+ on the Curie temperature, frequency dependent dielectric properties of the ferrite material are also discussed.
Body image predictors of depressive symptoms in adolescence
Authors: Murray Kristen , Rieger Elizabeth , Byrne Don
Published: October 2018

Introduction

Depression rises significantly in adolescence, with females reporting twice the prevalence of males into adulthood. In accordance with cognitive vulnerability theories, eating and weight‐related disturbances have been implicated in this increase, but a broader assessment of body image constructs within this framework is needed.

Methods

The current prospective study examined body importance, body dissatisfaction, and body change strategies to lose weight and increase muscularity as predictors of depressive symptoms over one year in N = 298 adolescents in Canberra, Australia (at Time 2, the sample comprised n = 161 female adolescents, Mage = 15.36 years, SD = 1.10; n = 137 male adolescents, Mage = 15.54 years, SD = 1.15). The moderating role of sex was also assessed.

Results & conclusions

Results revealed that body importance and body change strategies to increase muscularity explained significant variance in depressive symptoms beyond baseline covariates of depressive symptoms and stress, with the effect of body importance relevant in female but not male adolescents. The findings support the use of more comprehensive assessments of body image constructs to inform cognitive vulnerability theories of adolescent depression, and corresponding prevention and intervention programs.
Parasite and host biomass and reproductive output in barnacle populations in the rocky intertidal zone
Authors: Fong Caitlin R. , Kuris Armand M. , Hechinger Ryan F.
Published: October 2018

The rocky intertidal zone has a long history of ecological study with barnacles frequently serving as a model system to explore foundational theories. Parasites are often ignored in community ecology studies, and this particularly holds for true for the rocky intertidal zone. We explore the role of the isopod parasite,Hemioniscus balani, on its host, the acorn barnacle,Chthamalus fissus.We use the currencies of biomass and reproduction measured at the individual level, then applied to the population level, to evaluate the importance of this parasite to barnacle populations. We foundH. balanican comprise substantial biomass in ‘apparent’ barnacle populations, sometimes even equaling barnacle biomass. Additionally, parasite reproduction sometimes matched barnacle reproduction. Thus, parasites divert substantial energy flow from the barnacle population and to near-shore communities in the form of parasite larvae. Parasites appeared to decrease barnacle reproduction per area. Potentially, this parasite may control barnacle populations, depending on the extent to which heavily infected barnacle populations contribute to barnacle populations at larger scales. These findings regarding the importance of a particular parasite for host population dynamics in this well studied ecosystem call for the integration of disease dynamics into community ecological studies of the rocky intertidal zone.
The Impact of Cash Transfers: A Review of the Evidence from Low- and Middle-income Countries
Authors: BASTAGLI FRANCESCA , HAGEN-ZANKER JESSICA , HARMAN LUKE , BARCA VALENTINA , STURGE GEORGINA , SCHMIDT TANJA
Published: October 2018

This article presents the findings of a review of the impact of non-contributory cash transfers on individuals and households in low- and middle-income countries, covering the literature of 15 years, from 2000 to 2015. Based on evidence extracted from 165 studies, retrieved through a systematic search and screening process, this article discusses the impact of cash transfers on 35 indicators covering six outcome areas: monetary poverty; education; health and nutrition; savings, investment and production; work; and empowerment. For most of the studies, cash transfers contributed to progress in the selected indicators in the direction intended by policymakers. Despite variations in the size and strength of the underlying evidence base by outcome and indicator, this finding is consistent across all outcome areas. The article also investigates unintended effects of cash transfer receipt, such as potential reductions in adult work effort and increased fertility, finding limited evidence for such unintended effects. Finally, the article highlights gaps in the evidence base and areas which would benefit from additional future research.
Arnold Mitchell (1863–1944): ‘Fecundity’ and ‘Versatility’ in an Early Twentieth-Century Architect
Authors: Sherriff Clare
Published: October 2018

The architectural historian Roderick Gradidge, referring to the 1900s, wrote that ‘in architecture there have never been such opportunities for younger men as there were at the turn of the century’. Arnold Mitchell is an architect typical of those who took advantage of such opportunities, a man (women were yet to have the chance) who saw the economic and aesthetic potential for new architecture, both nationally and internationally. Understanding the nature of architectural practice should not be reliant solely upon knowledge of the stellar architects of any given period. It depends upon integrating others, one or two rungs down the ladder but who achieved success in their own sphere, into the corpus examined, in order to achieve a fuller understanding of the profession.
The Anglo-Indian Architect Walter Sykes George (1881–1962): a Modernist Follower of Lutyens
Authors: Butler Richard
Published: October 2018

[Lutyens’s system of proportion] began the link between us, by a chance action of mine, within the first year of my meeting him. He would never discuss it. It was intensely personal to him. [… He once] spoke to a group of students. One asked ‘What is proportion?’ and he answered ‘God’.

(Walter Sykes George to Hope Bagenal, January 1959)

Walter Sykes George (1881–1962) (Fig. 1) was a remarkable Anglo-Indian architect. Obituaries in Indian and British journals cast him as a ‘Renaissance’ man: an artist, Byzantine archaeologist, architect, town planner, philosopher, historian, public intellectual, humanist, Modernist, even an Indian nationalist. He features prominently in one recent history of modern architecture in India, a rare accolade for an ‘Anglo-Indian’ architect — an architect born in Britain who practised and lived for much of his life in India.
Tomb Architecture of Dynastic China: Old and New Questions
Authors: Guo Qinghua
Published: October 2018

A significant number of tombs have survived from the Han dynasty (Western Han 206 BC-AD 8, Eastern Han 25–220), an important period for tomb architecture in China. The number of examples is in stark contrast to the lack of evidence of other architecture from the period. In fact, no timber architecture built before the Tang dynasty (618–907) exists today. While much care and scholarly effort has been devoted to the interpretation of ancient architecture, funeral architecture has not received adequate study and scrutiny.
Non-Aligned Architecture: China’s Designs on and in Ghana and Guinea, 1955-92
Authors: Roskam Cole
Published: October 2018

The current international attention devoted to contemporary Chinese-financed and constructed development in Africa has tended to obscure complex and multivalent histories of the relationships between the People’s Republic of China (PRC) and numerous African nations; and many of these histories date back decades. The ideological origins behind socialist China’s engagement with Africa, and the geopolitical dynamics that continue to propel them forward, trace back to the time of Chairman Mao Zedong, who first coined the term ‘intermediate zone’ in 1946 to position the vast expanse of contested territories and undecided loyalties existing between the ideological poles of the Soviet Union and the United States after World War II. Nine years later (1955), at the first Non-Aligned Movement conference held in Bandung, Indonesia, Chinese Premier Zhou Enlai declared that

ever since modern times most of the countries of Asia and Africa in varying degrees have been subjected to colonial plunder and oppression, and have thus been forced to remain in a stagnant state of poverty and backwardness […]. We need to develop our countries independently with no outside interference and in accordance with the will of the people.
Of Crystals, Cells, and Strata: Natural History and Debates on the Form of a New Architecture in the Nineteenth Century
Authors: Bergdoll Barry
Published: October 2018

One of the most peculiar texts of French Romanticism is Jules Michelet’s today little-read tome,L’Insecte(1857), a fascinating forerunner of FranzKafka’s Metamorphosis. In Book 2, Chapter 8, entitled ‘De la rénovation de nos arts par l’étude de l’Insecte’ [On the renovation of our arts through studying insects]. Michelet writes there already of two themes that are central to the panorama of intersections between natural history thinking and architectural thought and practice outlined in this essay (itself an interim report on a much longer research project). Here I can take up only some key episodes in the veritable explosion of interest throughout the long nineteenth century (1789 to 1914), and after 1850 in particular: in inorganic and organic nature as sources of inspiration, models even, in the quest to confront the challenges not only of modern society and construction but also of the yearning for a modern style in architecture, and the issue of the new ability to see rather than intuit the inner workings of nature. Michelet writes:
Drawing from an Indigenous Tradition? George Gilbert Scott’s First Design for Christchurch Cathedral, 1861-62
Authors: Skinner Robin
Published: October 2018

In 1861 Scott designed an innovative hybrid for Christchurch Cathedral, New Zealand, combining a stone exterior with an independent wooden interior, at once expression of the primitive ruggedness of what he imagined to be the Maori wood tradition and an experimental response for this earthquake-prone colony.

Commissioning George Gilbert Scott (1811-78) to design a cathedral for the relatively new settlement at Christchurch, in the province of Canterbury, New Zealand, was an ambitious undertaking by a predominantly Anglican community that had been established only eleven years earlier. The cathedral, which was constructed between late 1864 and 1904, was a conventional stone building, designed by Scott and executed locally by B. W. Mountfort. However, in an unusually experimental move, Scott had earlier proposed a structure that incorporated a stone exterior with an interior frame made of a series of high piers of New Zealand native timber, each almost 50 feet tall. The dramatic interior of this proposal referenced a wide variety of timber- and church-building traditions; had it been constructed, its tall wooden structure would have been ‘unique amongst colonial cathedrals’. After examining previously discussed sources for his design, this paper speculates upon further influences, testing — in particular — Barry Bergdoll’s assertion that the design was an expression of the ‘primitive ruggedness’ that Scott imagined derived from Maori work in wood, examples of which had been known in Europe since the 1770s.
Horace Field and Lloyds Bank
Authors: Brittain-Catlin Timothy
Published: October 2018

In 1980, Andrew Saint told members of the Victorian Society that the Arts and Crafts architect Horace Field (1861-1948) was ‘frequently referred to but rarely discussed’. Thirty years later the situation is largely unchanged. Yet Field played an influential role in the architectural development of the twentieth-century English and Welsh high street. He was a significant figure in the process by which the architectural styles of bank premises were, by the late 1920s, transformed from ones very similar to those of commercial or municipal offices into a distinct and domestic interpretation of the style of Queen Anne. His contribution was two-fold: as the designer of a series of branches of Lloyds Bank, and as co-author (with his former assistant, Michael Bunney) of the widely read English Domestic Architecture of the XVII and XVIII Centuries, published in 1905.
Building on the Backs: Basil Spence, Queens’ College Cambridge and University Architecture at Mid-Century
Authors: Campbell Louise
Published: October 2018

Higher Education in Britain expanded dramatically during the 1950s and 1960s. The trigger for growth was the Barlow Report of 1946, which recommended an immediate doubling of the number of science students and an increase in the total number of student places, of which there had been c. 50,000 in 1939, to 70,000 by 1950 and 90,000 by 1955. The 1963 Robbins Report continued and accelerated this expansionist policy, proposing that half a million student places be created by 1980. In the event, although funding was less generous than Barlow had recommended, the numbers achieved were far greater, and 85,000 students were in Higher Education by 1950. The impetus for this growth, which included the foundation of seven new universities (the so-called ‘Shakespearean Seven’) and the enlargement of existing institutions, stemmed from an ambitious vision of the role of universities after the Second World War. Higher Education, and particularly scientific training, was seen as one way to maintain Britain’s position on the world stage. Equally important was the principle of widening access, and a concern to broaden the social base of university education found expression in a range of new approaches to design. Within this context, the universities of Oxford and Cambridge also witnessed significant expansion, but in a very particular way and with distinctive results on account of these universities’ collegiate structure. As elsewhere, buildings at Oxbridge for teaching and research were dependent on finance from the University Grants Committee, but the semi-autonomous colleges could draw on their own (sometimes considerable) resources when it came to building. Furthermore, college dons could exercise significantly more influence over the choice of architect than was possible elsewhere. The colleges of Oxford and Cambridge therefore provided an important environment in which new architectural ideas could be explored. An early contribution to the debate was made by the Erasmus Building, a residential block at Queens’ College, Cambridge, designed by Basil Spence in 1958 (Fig. 1). Although the history of Spence’s design is inextricably bound up with its Cambridge context, as an attempt to reformulate the collegiate ideal it also offers a foretaste of the debates that shaped the new universities in the decade that followed.
Against ‘Churchianity’: Edmund Anscombe’s Suburban Church Designs
Authors: McCarthy Christine
Published: October 2018

Edmund Anscombe (1874-1948) was an important New Zealand architect, well known for his design of the 1925 New Zealand and South Seas International Exhibition (Logan Park, Dunedin) and the 1940 New Zealand Centennial Exhibition (Rongotai, Wellington), as well as for his art deco buildings in Hawkes Bay (especially Hastings), and in Wellington.

This article explores Anscombe’s contribution to New Zealand’s early twentieth-century church design by presenting new archival research and examining his distinctive use of secular imagery, notably the architectures of the house and schoolhouse. The article locates these designs simultaneously within traditions of Nonconformist architecture and within a Victorian interest in the home as productively informing a spiritual understanding of church building. While some architectural examples of this thinking were apparent in late nineteenth-century America, there are no other known examples in New Zealand. Anscombe’s use of this secular and domestic imagery in his church design enabled fashionable and theologically-informed architectures to co-exist.
Industry use of ‘better-for-you’ features on labels of sugar-containing beverages
Authors: Brownbill Aimee L , Miller Caroline L , Braunack-Mayer Annette J
Published: October 2018

Objective

To examine the ways in which sugar-containing beverages are being portrayed as ‘better-for-you’ (BFY) via features on product labels.

Design

Cross-sectional audit of beverage labels.

Setting

Adelaide, Australia. Data on beverage labels were collected from seventeen grocery stores during September to November 2016.

Subjects

The content of 945 sugar-containing beverages labels were analysed for explicit and implicit features positioning them as healthy or BFY.

Results

The mean sugar content of beverages was high at 8·3 g/100 ml and most sugar-containing beverages (87·7 %) displayed features that position them as BFY. This was most commonly achieved by indicating the beverages are natural (76·8 %), or contain reduced or natural energy/sugar content (48·4 %), or through suggesting that they contribute to meeting bodily needs for nutrition (28·9 %) or health (15·1 %). Features positioning beverages as BFY were more common among certain categories of beverages, namely coconut waters, iced teas, sports drinks and juices.

Conclusions

A large proportion of sugar-containing beverages use features on labels that position them as healthy or BFY despite containing high amounts of sugar.
Revisiting the spore assemblages from the Lower Devonian Posongchong Formation of Wenshan, Yunnan Province, southwestern China
Authors: Cascales-Miñana B. , Xue J. Z. , Rial G. , Gerrienne P. , Huang P. , Steemans P.
Published: October 2018

The Lower Devonian Posongchong Formation (Wenshan, Yunnan Province, southwestern China) consists of a series of continental deposits with an outstanding plant megafossil diversity. More than 20 years ago, this formation was interpreted as ‘Siegenian' (∼Pragian) in age based on palynology. However, such interpretation needs further evidence because of the known differences between the dispersed spore assemblages from South China and Euramerica/northwestern Gondwana. Here, we present new dispersed spore assemblages recently recovered from the Posongchong Formation. The isolated spore diversity is highly diverse, with 18 genera and 32 species. The recognised taxa include, among others, Ambitisporites avitus, Aneurospora conica, Aneurospora posongchongensis sp. nov., Aneurospora xujiachongensis, Apiculiretusispora plicata, Archaeozonotriletes chulus, Concentricosisporites agradabilis, Dibolisporites echinaceus, Emphanisporites rotatus, Gneudnaspora divellomedia, Latosporites ovalis, Retusotriletes triangulatus, Tetrahedraletes medinensis and Verrucosporites polygonalis, with Aneurospora and Retusotriletes being the most abundant forms. The known Posongchong palynoflora (previous spore data included) suggests that the Posongchong Formation assemblages can be correlated with the Pragian interval of the polygonalis–wetteldorfensis Oppel Zone (PoW). This age determination is supported by the presence of index species of PoW, such as Verrucosporites polygonalis, Dictyotriletes subgranifer and Camarozonotriletes parvus (sensu Steemans, 1989), the latter being known only from the Pragian of Belgium and Germany. Recent advances in the study of the marine faunas in the overlying sequences also indicate a Pragian age for the Posongchong Formation. This new investigation of the Posongchong palynoflora highlights differences of abundance at species level between the Gondwanan–Laurussian floras during the Early Devonian.
Synoptic Circulation Impact on the Near‐Surface Temperature Difference Outweighs That of the Seasonal Signal in the Eastern Mediterranean
Authors: Lensky Itamar M. , Dayan Uri , Helman David
Published: October 2018

Near‐surface temperature difference (i.e., the difference between land surface skin and 2‐m air temperatures—ΔT) drives numerous ecological and biophysical processes on Earth, constituting an essential parameter in process‐based Earth System Modeling. ΔT is known to be governed by factors like incoming solar radiation and wind, which vary according to synoptic‐scale circulation via horizontal pressure gradient and cloud cover. ΔT is also affected by land surface characteristics and vegetation dynamics. Here we assess the role of seasonality, synoptic‐scale circulation, and vegetation dynamics, using satellite normalized difference vegetation index (NDVI) and latent heat estimates, on the ΔT in the Eastern Mediterranean (EM). ΔT was calculated using land surface temperatures derived from the Moderate Resolution Imaging Spectroradiometer and air temperatures measured at 94 meteorological stations in the EM for 2006–2010. The effect of circulation on ΔT is demonstrated for four synoptic categories covering all seasons, showing that the influence of synoptic‐scale circulation may be sometimes stronger than that of the seasonal signal in this region. ΔT showed negative relationships with NDVI indicating that vegetation is attenuating the near ground temperature difference, with a gradual effect increasing from southern drylands to the more humid northern vegetated areas in the EM. The relationship between ΔT and NDVI was stronger for specific synoptic classes than for seasonal division, implying the combined role of vegetation cover dynamics and synoptic‐scale conditions on ΔT. Findings from this study show promise for continuous spatiotemporal estimations of ΔT from land surface temperature and NDVI satellite data.
Observing Winter Mixing and Spring Bloom in the Mediterranean
Authors: Conan Pascal , Testor Pierre , Estournel Claude , D'Ortenzio Fabrizio , Durrieu de Madron Xavier
Published: October 2018

A new special issue of JGR: Oceans and JGR: Atmospheres presents new insights into the dynamics of dense water formation in the western Mediterranean Sea and its biogeochemical consequences.
Stronger Local Overturning in Convective‐Permitting Regional Climate Model Improves Simulation of the Subtropical Annual Cycle
Authors: Hart Neil C. G. , Washington Richard , Stratton Rachel A.
Published: October 2018

Global climate models fail to represent the annual cycle of tropical‐extratropical cloud bands and produce too much summer rainfall over subtropical southern Africa. This study demonstrates that running a regional convective‐permitting climate simulation alleviates these biases, counteracting biases that are present in the parent model. The improvement emerges from stronger vertical mass flux in the tropics, which forces a stronger local Hadley overturning into the summer hemisphere. This enhanced overturning increases upper‐level subsidence in the subtropics and amplifies the forcing of the local subtropical jet. Together, these improvements halve the wet subtropical rainfall bias and are associated with a 50% increase to an 80% match between the simulated and observed annual cycle of crucial tropical‐extratropical cloud band rainfall systems. The results advocate for the increased use of convective‐permitting climate models with domains that include regional tropical convection hot spots, in order to fully benefit from the explicit representation of deep convection.
Coral Reef Island Initiation and Development Under Higher Than Present Sea Levels
Authors: East H. K. , Perry C. T. , Kench P. S. , Liang Y. , Gulliver P.
Published: October 2018

Coral reef islands are considered to be among the most vulnerable environments to future sea level rise. However, emerging data suggest that different island types, in contrasting locations, have formed under different conditions in relation to past sea level. Uniform assumptions about reef island futures under sea level rise may thus be inappropriate. Using chronostratigraphic analysis from atoll rim islands (sand‐ and gravel‐based) in the southern Maldives, we show that while island building initiated at different times around the atoll (~2,800 and ~4,200 calibrated years before present at windward and leeward rim sites, respectively), higher than present sea levels and associated high‐energy wave events were actually critical to island initiation. Findings thus suggest that projected sea level rise and increases in the magnitude of distal high‐energy wave events could reactivate this process regime, which, if there is an appropriate sediment supply, may facilitate further vertical reef island building.
Anomalous Zeta Potential Trends in Natural Sandstones
Authors: Li Shuai , Collini Harry , Jackson Matthew D.
Published: October 2018

It is widely accepted that the zeta potential in natural sandstones is negative and becomes larger in magnitude with decreasing electrolyte concentration. In our experimental measurements of zeta potential, an almost pure quartz sandstone saturated with NaCl electrolyte followed this expected concentration dependence. However, the zeta potential in a clay‐ and dolomite‐bearing sandstone initially increased but then decreased in magnitude with decreasing NaCl concentration. The effluent contained Ca2+ cations, although none were injected. At the lowest NaCl concentration tested, the zeta potential was identical within experimental error to that measured using CaCl2 electrolyte with the same concentration. We argue that Ca2+ cations can be released from natural sandstones by mineral dissolution or ion exchange and these ions are preferentially adsorbed onto quartz mineral surfaces, dominating the behavior of the zeta potential at low NaCl concentration. The results have broad implications for the zeta potential of natural sandstones in subsurface settings.
Coulomb Stress Transfer Influences Fault Reactivation in Areas of Wastewater Injection
Authors: Qin Yan , Chen Xiaowei , Carpenter Brett M. , Kolawole Folarin
Published: October 2018

We explore the role of Coulomb stress transfer in the fault reactivation in Woodward, Oklahoma—a wastewater injection area. We address this issue by first defining fault segments from earthquake spatiotemporal clustering then parameterizing the geometries of each segment by combining seismicity and focal mechanisms. Finally, we calculate Coulomb stress transfer along each fault segment. Our results reveal a fault system characterized by a flower structure with strike‐slip fault at deeper depth and distributed normal faults at shallower depth. Further, Coulomb stress analysis reveals that the fault reactivation initiates at the fault bend and sequentially migrates to northeast and southwest due to interevent stress interaction. The amplitude of Coulomb stress transfer is at least comparable to pore pressure and poroelastic stress changes estimated from fluid injection. Overall, our observations suggest that fault structure and Coulomb stress transfer constitute important factors in seismogenic fault reactivation within areas of wastewater injection.
Linkage Between Westerly Wind Bursts and Tropical Cyclones
Authors: Lian Tao , Chen Dake , Tang Youmin , Liu Xiaohui , Feng Jie , Zhou Lei
Published: October 2018

The westerly wind burst (WWB) in the equatorial Pacific strongly impacts on the genesis and diversity of El Niño, as manifested by its crucial role in the 2014–2016 El Niño events. However, the origin of WWB is still far from clear, rendering El Niño prediction, a persistently challenging task. Here we confirm a robust linkage between WWB and tropical cyclone (TC) from a set of observational and reanalysis data. Specifically, about 69% of WWBs were closely associated with TCs in the western tropical Pacific, and the three‐dimensional structure of WWBs highly resembled that of TCs. Such a close relationship readily explains not only the unidirectional and intermittent nature of WWBs but also the state dependency, seasonality, and spatial distribution of these bursts. An important implication is that, with skillful seasonal forecast of WWB‐associated TCs, we may be able to predict the seasonal activity of WWBs and thus improve El Niño prediction.
Tropical Decadal Variability and the Rate of Arctic Sea Ice Decrease
Authors: Meehl Gerald A. , Chung Christine T. Y. , Arblaster Julie M. , Holland Marika M. , Bitz Cecilia M.
Published: October 2018

The trend for cold‐season (November‐December‐January‐February, NDJF) decreases in Arctic sea ice extent from 2000 to 2014 was about a factor of two larger than the 1979–2000 trend, and the warm‐season (June‐July‐August‐September, JJAS) trend was about a factor of three larger. Sensitivity experiments with an atmospheric model show that a negative convective heating anomaly in the tropical Pacific, associated with the negative Interdecadal Pacific Oscillation phase after 2000, produces an atmospheric teleconnection pattern over the Arctic comparable to the observations in NDJF but not JJAS. A positive convective heating anomaly over the tropical Atlantic, associated with warming sea surface temperatures there in the 2000–2014 period, produces a teleconnection pattern over the Arctic comparable to the observations in JJAS but not NDJF. Thus, the observed anomalously strong Arctic surface winds and sea ice drifts after 2000, which produced accelerated decreases in sea ice extent, likely had contributions from decadal‐time scale variability in the tropical Pacific and Atlantic.
Correlations Between the Thermosphere's Semiannual Density Variations and Infrared Emissions Measured With the SABER Instrument
Authors: Weimer D. R. , Mlynczak M. G. , Emmert J. T. , Doornbos E. , Sutton E. K. , Hunt L. A.
Published: October 2018

This paper presents measurements of the amplitudes and timings of the combined, annual, and semiannual variations of thermospheric neutral density, and a comparison of these density variations with measurements of the infrared emissions from carbon dioxide and nitric oxide in the thermosphere. The density values were obtained from measurements of the atmospheric drag experienced by the Challenging Minisatellite Payload, Gravity Recovery and Climate Experiment A, Gravity field and Ocean Circulation Explorer, and three Swarm satellites, while the optical emissions were measured with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite. These data span a time period of 16 years. A database containing global average densities that were derived from the orbits of about 5,000 objects (Emmert, 2009, https://doi.org/10.1029/2009JA014102, 2015b, https://doi.org/10.1002/2015JA021047) was employed for calibrating these density data. A comparison with the NRLMSISE‐00 model was used to derive measurements of how much the density changes over time due to these seasonal variations. It is found that the seasonal density oscillations have significant variations in amplitude and timing. In order to test the practicality of using optical emissions as a monitoring tool, the SABER data were fit to the measured variations. Even the most simple fit that used only filtered carbon dioxide emissions had good correlations with the measured oscillations. However, the density oscillations were also well predicted by a simple Fourier series, contrary to original expectations. Nevertheless, measurements of the optical emissions from the thermosphere are expected to have a role in future understanding and prediction of the semiannual variations.
Arctic‐Wide Sea Ice Thickness Estimates From Combining Satellite Remote Sensing Data and a Dynamic Ice‐Ocean Model with Data Assimilation During the CryoSat‐2 Period
Authors: Mu Longjiang , Losch Martin , Yang Qinghua , Ricker Robert , Losa Svetlana N. , Nerger Lars
Published: October 2018

Exploiting the complementary character of CryoSat‐2 and Soil Moisture and Ocean Salinity satellite sea ice thickness products, daily Arctic sea ice thickness estimates from October 2010 to December 2016 are generated by an Arctic regional ice‐ocean model with satellite thickness assimilated. The assimilation is performed by a Local Error Subspace Transform Kalman filter coded in the Parallel Data Assimilation Framework. The new estimates can be generally thought of as combined model and satellite thickness (CMST). It combines the skill of satellite thickness assimilation in the freezing season with the model skill in the melting season, when neither CryoSat‐2 nor Soil Moisture and Ocean Salinity sea ice thickness is available. Comparisons with in situ observations from the Beaufort Gyre Exploration Project, Ice Mass Balance Buoys, and the NASA Operation IceBridge demonstrate that CMST reproduces most of the observed temporal and spatial variations. Results also show that CMST compares favorably to the Pan‐Arctic Ice‐Ocean Modeling and Assimilation System product and even appears to correct known thickness biases in the Pan‐Arctic Ice‐Ocean Modeling and Assimilation System. Due to imperfect parameterizations in the sea ice model and satellite thickness retrievals, CMST does not reproduce the heavily deformed and ridged sea ice along the northern coast of the Canadian Arctic Archipelago and Greenland. With the new Arctic sea ice thickness estimates sea ice volume changes in recent years can be further assessed.
The Simulation of East Asian Summer Monsoon Precipitation With a Regional Ocean‐Atmosphere Coupled Model
Authors: Dai Yongjiu , Li Haiqin , Sun Liqiang
Published: October 2018

A fully coupled regional ocean‐atmosphere model was used to simulate the East Asian summer monsoon (EASM) precipitation. This coupled regional climate modeling system consists of the Regional Spectral Model (RSM) for the atmosphere and the Regional Ocean Modeling System for the ocean. The ocean and atmosphere share the same horizontal grid resolution. The coupled model is forced by the National Centers for Environmental Prediction‐Department of Energy (R‐2) global atmospheric reanalysis and Simplified Ocean Data Assimilation global oceanic reanalysis through the lateral boundary. This study examines EASM surface oceanic state and precipitation variability from a 22‐year (1984–2005) integration with a horizontal resolution of 40 km. The coupled model captures the features of observed sea surface temperature (SST), sea surface height, and ocean surface currents. Compared with the control run of the uncoupled RSM forced with observed SSTs, the coupled model shows more realistic simulation of the EASM precipitation climatology. The coupled model also improves the simulation of precipitation variability at both interannual and intraseasonal scales. It is the coupled model, not the uncoupled RSM, represents the observed SST‐precipitation and SST‐evaporation relationships. This study indicates that the ocean‐atmosphere coupling is essential for model simulations of the EASM precipitation.
Model Resolution Sensitivity of the Simulation of North Atlantic Oscillation Teleconnections to Precipitation Extremes
Authors: Mahajan Salil , Evans Katherine J. , Branstetter Marcia L. , Tang Qi
Published: October 2018

We evaluate a high‐resolution (0.25°), four‐member ensemble simulation of the global climate (1979–2005) with the U.S. Department of Energy's Energy Exascale Earth System Model v0.3—forced with observed ocean surface temperatures and sea ice extent—for its ability to represent the North Atlantic Oscillation (NAO) teleconnections to winter precipitation extremes over western Europe. As compared to the low‐resolution model (1°), it simulates a stronger impact of NAO on daily precipitation extremes over the western slopes of mountain ranges over southwestern Norway, northwestern United Kingdom, and the Western Balkan states. Precipitation extremes and their linear relationship with NAO are quantified using the generalized extreme value distribution. NAO‐dependent large‐scale (stratiform) precipitation intensity strengthens in the high‐resolution model on seasonal time scales and plays a dominant role during simulated daily precipitation extremes. Improvements in the high‐resolution model over these varied‐topography regions largely appear to be due to finer resolved scales of motion that amplify NAO‐dependent seasonal vertical moisture fluxes and enhance stable condensation. However, the high‐resolution model simulates a weaker than observed impact of NAO on extratropical cyclone activity and total precipitable water, generally underperforming the low‐resolution model These effects possibly offset the impact of enhanced vertical moisture fluxes on NAO‐dependent precipitation extremes in the high‐resolution model in these regions. Over the southwestern Iberian peninsula, the high‐resolution model underperforms the low‐resolution model simulating weaker than observed impact of NAO on precipitation extremes. This appears to be due to the reduction in total precipitable water despite an increase in NAO‐dependent extratropical activity there.
The Linkage Between Arctic Sea Ice and Midlatitude Weather: In the Perspective of Energy
Authors: Gu Sen , Zhang Yang , Wu Qigang , Yang Xiu‐Qun
Published: October 2018

The influence of Arctic changes on the weather in the highly populated midlatitude is a controversial topic with little agreements regarding its existence or its mechanism. Utilizing eddy energy as metrics of circulation and temperature fluctuations with weather patterns, this study highlights the robust relationship between the early autumn Arctic sea ice and the wintertime transient activities over northern Eurasia on interannual time scale, by comparing groups of statistical and diagnostical results. With the reduction of sea ice in early autumn in Barents, Kara, Laptev, and East Siberia Seas, the atmosphere over those polar regions exhibits significant increase in eddy energy in the following winter. In the adjacent Eurasia, the wintertime synoptic eddy energy decreases, while the low‐frequency eddy energy, corresponding to persistent weather patterns, exhibits evident and dominant increase. The enhanced southward energy propagation of low‐frequency waves from the polar region to the north of middle‐to‐east Asia suggests a mechanism for the Arctic‐midlatitude linkage, indicating that Arctic sea ice could be a source of predictability for both extended‐range and subseasonal to seasonal forecasts.
Polar Jet Associated Circulation Triggered a Saharan Cyclone and Derived the Poleward Transport of the African Dust Generated by the Cyclone
Authors: Francis Diana , Eayrs Clare , Chaboureau Jean‐Pierre , Mote Thomas , Holland David M.
Published: October 2018

In this study, we identify a new mechanism by which dust aerosols travel over long distances across the eastern side of the North Atlantic Ocean toward the Arctic. The meandering polar jet was at the origin of both dust emission through cyclogenesis over Northwest Africa and poleward transport of the uplifted dust toward the Arctic, through cut‐off circulation. The dust emission was associated with an intense Saharan cyclone that formed over Northwest Africa in early April 2011. The formation of the cyclone was caused by the intrusion into subtropics, of a high‐latitude‐upper‐level trough, linked to the meandering polar jet. The trough initiated cyclogenesis over Northwest Africa after orographic blocking by the Anti‐Atlas Mountains. The still meandering polar jet led to the formation of a cut‐off low further south with which the Saharan dust‐cyclone merged 2 days later and moved northward with the main stream. Beside satellite observations, a simulation at high resolution was performed using the prognostic‐dust permitting model MesoNH. The total dust load carried during this event to areas located north of 40 N was estimated by the model to be 38 Tg and dust deposition was estimated to be 1.3 Tg. The Saharan dust reaching Greenland was accompanied by warm and moist air masses that caused a rise in surface temperature of about 10C for more than 3 consecutive days over the southeastern Greenland. Ice melt over this area of Greenland was detected in the brightness temperature observations.
Nitrogen Oxides Emissions, Chemistry, Deposition, and Export Over the Northeast United States During the WINTER Aircraft Campaign
Authors: Jaeglé L. , Shah V. , Thornton J. A. , Lopez‐Hilfiker F. D. , Lee B. H. , McDuffie E. E. , Fibiger D. , Brown S. S. , Veres P. , Sparks T. L. , Ebben C. J. , Wooldridge P. J. , Kenagy H. S. , Cohen R. C. , Weinheimer A. J. , Campos T. L. , Montzka D. D. , Digangi J. P. , Wolfe G. M. , Hanisco T. , Schroder J. C. , Campuzano‐Jost P. , Day D. A. , Jimenez J. L. , Sullivan A. P. , Guo H. , Weber R. J.
Published: October 2018

We examine the distribution and fate of nitrogen oxides (NOx) in the lower troposphere over the Northeast United States (NE US) using aircraft observations from the Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER) campaign in February–March 2015, as well as the GEOS‐Chem chemical transport model and concurrent ground‐based observations. We find that the National Emission Inventory from the U.S. Environmental Protection Agency is consistent with WINTER observations of total reactive nitrogen (TNOy) to within 10% on average, in contrast to the significant overestimate reported in past studies under warmer conditions. Updates to the dry deposition scheme and dinitrogen pentoxide (N2O5) reactive uptake probability, ɣ(N2O5), result in an improved simulation of gas‐phase nitric acid (HNO3) and submicron particulate nitrate (pNO3−), reducing the longstanding factor of 2–3 overestimate in wintertime HNO3 + pNO3− to a 50% positive bias. We find a NOx lifetime against chemical loss and deposition of 22 hr in the lower troposphere over the NE US. Chemical loss of NOx is dominated by N2O5 hydrolysis (58% of loss) and reaction with OH (33%), while 7% of NOx leads to the production of organic nitrates. Wet and dry deposition account for 55% and 45% of TNOy deposition over land, respectively. We estimate that 42% of the NOx emitted is exported from the NE US boundary layer during winter, mostly in the form of HNO3 + pNO3− (40%) and NOx (38%).
Latitudinal Double‐Peak Structure of Stationary Planetary Wave 1 in the Austral Winter Middle Atmosphere and Its Possible Generation Mechanism
Authors: Lu Xian , Wu Haonan , Oberheide Jens , Liu Han‐Li , McInerney Joseph M.
Published: October 2018

We report a hitherto unknown latitudinal double‐peak structure in the amplitude of stationary planetary wave 1 (SPW1) geopotential height in the stratosphere and lower mesosphere during austral winter. The primary peak is located at 60–70°S and 30–40 km, and the secondary peak is at 30–50°S and 40–60 km. According to 36 years (1981–2016) of the Modern‐Era Retrospective analysis for Research and Applications, version 2, reanalysis data, the double‐peak structure occurs with frequencies of ~61%, 97%, 53%, and 25% in May, June, July and August, respectively, while it rarely exists in other seasons. Significant downward Eliassen‐Palm fluxes suggestive of downward‐propagating waves are often found above the secondary peak, and phase progressions show opposite directions on its two sides. From the free‐running Whole Atmosphere Community Climate Model and linear mechanistic model simulations, the secondary peak is likely generated by the interference of primary upward‐ and secondary downward‐propagating SPW1 excited in situ by gravity wave forcing in the upper mesosphere. The strengths of the primary and secondary waves need to be comparable to form an effective interference pattern, which may explain the missing double‐peak feature in boreal winter as the primary waves are too dominant. Summer‐to‐winter interhemispheric wave coupling is identified in the austral midwinter and appears to originate from the secondary SPW1 generated in the summer hemisphere. Since the double‐peak structure of SPW1 is sensitive to the mean wind, wave‐mean flow, and wave‐wave interactions, this study provides a reference for general circulation and mechanistic models to simulate the middle atmosphere wave dynamics in austral winter.