bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying sensitivity in numerical weather prediction‐modeled offshore wind speeds through an ensemble modeling approach
Authors: Optis Mike , Kumler Andrew , Brodie Joseph , Miles Travis
Published: February 2021

A decade of research has shown that numerical weather prediction (NWP)‐modeled wind speeds can be highly sensitive to the inputs and setups within the NWP model. For wind resource characterization applications, this sensitivity is often addressed by constructing a range of setups and selecting the one that best validates against observations. However, this approach is not possible in areas that lack high‐quality hub height observations, especially offshore wind areas. In such cases, techniques to quantify and disseminate confidence in NWP‐modeled wind speeds in the absence of observations are needed. We address this need in the present study and propose best practices for quantifying the spread in NWP‐modeled wind speeds. We implement an ensemble approach in which we consider 24 different setups to the Weather Research and Forecasting (WRF) model. We construct the ensemble by considering variations in WRF version, WRF namelist, atmospheric forcing, and sea surface temperature (SST) forcing. Our analysis finds that the standard deviation produces more consistent estimates compared to the interquartile range and tends to be the more conservative estimator for ensemble variability. We further find that model spread increases closer to the surface and on shorter time scales. Finally, we explore methods to attribute total ensemble variability to the different ensemble components (e.g., atmospheric forcing and SST product) and find that contributions by components also vary depending on time scale. We anticipate that the methods and results presented in this paper will provide a reasonable foundation for further research into ensemble‐based wind resource data sets.
Rationale for constant flow to optimize wastewater treatment and advanced water treatment performance for potable reuse applications
Authors: Tchobanoglous George , Kenny John , Leverenz Harold
Published: February 2021

Population growth, the impacts of climate change, and the need for greater water security have made the reuse of wastewater, including potable use, increasingly desirable. As interest in potable reuse of wastewater increases, a variety of processes have been proposed for advanced water treatment following conventional wastewater treatment. In all cases, the operation and performance of advanced water treatment facilities (AWTFs) is improved when the treated wastewater feed is of the highest quality that can be achieved and the advanced water treatment (AWT) processes are operated at a constant flow. One proven method of optimizing the performance of wastewater treatment facilities (WWTFs) is constant flow operation with no extraneous return flows other than internal process recycle flows, such as return settled solids. A number of approaches can be used to achieve constant flow including flow equalization, divided treatment trains, and satellite treatment. The ways in which constant flow wastewater treatment benefits both WWTFs as well as the AWTFs are considered with special emphasis on the ability to achieve predictable log removal credits (LRCs) for specific microorganisms. Actual performance data from constant flow WWTFs are used to illustrate how LRCs are determined.

Practitioner points

Constant flow WWTFs should be considered to produce the highest quality secondary effluent for AWT.

Flow equalization, divided treatment trains, and satellite treatment can be used to achieve constant flow to optimize wastewater treatment in small and medium size WWTFs.

Flow equalization can be used to maximize the amount of wastewater that can be recovered for potable reuse.

Important benefits of constant flow for wastewater treatment facilities include economic and operational savings, stable and predictable treatment performance, energy savings, ability to optimize performance for the removal of specific constituents, and the ability to assign pathogen log removal credits (LRCs).

Important benefits of constant flow and optimized WWT for AWTFs include economic and operational savings; less pretreatment needed, including energy and chemical usage; elimination of the need to cycle treatment processes; and added factor of safety with respect to the required pathogen LRCs.

In large WWTFs, constant flow for AWTFs will typically be achieved by effluent diversion; depending on the effluent quality additional pretreatment may be needed.

The design and implementation of WWTFs and AWTFs for potable reuse should be integrated for optimal performance and protection of public health.
Regulators of commensal and pathogenic life‐styles of an opportunistic fungus—Candida albicans
Authors: Rai Laxmi Shanker , Wijlick Lasse Van , Bougnoux Marie‐Elisabeth , Bachellier‐Bassi Sophie , d'Enfert Christophe
Published: February 2021

The yeast Candida albicans is primarily a commensal of humans that colonizes the mucosal surfaces of the gastrointestinal and genital tracts. Yet, C. albicans can under certain circumstances undergo a shift from commensalism to pathogenicity. This transition is governed by fungal factors such as morphological transitions, environmental cues for instance relationships with gut microbiota and the host immune system. C. albicans utilizes distinct sets of regulatory programs to colonize or infect its host and to evade the host defense systems. Moreover, an orchestrated iron acquisition mechanism operates to adapt to specific niches with variable iron availability. Studies on regulatory networks and morphogenesis of these two distinct modes of C. albicans growth, suggest that both yeast and hyphal forms exist in both growth patterns and the regulatory circuits are inter‐connected. Here, we summarize current knowledge about C. albicans commensal‐to‐pathogen shift, its regulatory elements and their contribution to human disease.
F-theory from fundamental five-branes
Authors: Linch William D. , Siegel Warren
Published: February 2021

Abstract

We describe the worldvolume for the bosonic sector of the lower-dimensional F-theory that embeds 4D, N=1 M-theory and the 3D Type II superstring. The worldvolume (5-brane) theory is that of a single 6D gauge 2-form XMN(σP) whose field strength is selfdual. Thus unlike string theory, the spacetime indices are tied to the worldsheet ones: in the Hamiltonian formalism, the spacetime coordinates are a 10 of the GL(5) of the 5 σ’s (neglecting τ). The current algebra gives a rederivation of the F-bracket. The background-independent subalgebra of the Virasoro algebra gives the usual section condition, while a new type of section condition follows from Gauß’s law, tying the worldvolume to spacetime: solving just the old condition yields M-theory, while solving only the new one gives the manifestly T-dual version of the string, and the combination produces the usual string. We also find a covariant form of the condition that dimensionally reduces the string coordinates.
Classical black hole scattering from a worldline quantum field theory
Authors: Mogull Gustav , Plefka Jan , Steinhoff Jan
Published: February 2021

Abstract

A precise link is derived between scalar-graviton S-matrix elements and expectation values of operators in a worldline quantum field theory (WQFT), both used to describe classical scattering of black holes. The link is formally provided by a worldline path integral representation of the graviton-dressed scalar propagator, which may be inserted into a traditional definition of the S-matrix in terms of time-ordered correlators. To calculate expectation values in the WQFT a new set of Feynman rules is introduced which treats the gravitational field hμν(x) and position $$ {x}_i^{\mu}\left({\tau}_i\right) $$

x
i
μ

τ
i

of each black hole on equal footing. Using these both the 3PM three-body gravitational radiation 〈hμv(k)〉 and 2PM two-body deflection $$ \Delta {p}_i^{\mu } $$
Δ

p
i
μ

from classical black hole scattering events are obtained. The latter can also be obtained from the eikonal phase of a 2 → 2 scalar S-matrix, which we show corresponds to the free energy of the WQFT.
Correction to: Deciphering the genetic and epidemiological landscape of mitochondrial DNA abundance
Authors: Hägg Sara , Jylhävä Juulia , Wang Yunzhang , Czene Kamila , Grassmann Felix
Published: February 2021

In the original article, the acknowledgement section is incorrectly published. The correct acknowledgement is
Shared and Supported Decision Making in Medication in a Mental Health Setting: How Far Have We Come?
Authors: Pappa Sofia , Barnett Joshua , Gomme Sally , Iliopoulou Anthi , Moore Ivan , Whitaker Michael , McGrath Jane , Sie Michele
Published: February 2021

Personalised care involves shared decision making (SDM) across all levels including choice in medication. However, there are a number of barriers which prevent its effective implementation in routine mental health settings. Therefore, we undertook a study to benchmark current practice across clinical services of a large urban mental health provider. The study formed part of the trust-wide ‘Supported Decision Making in Medication’ Co-Production Project and aims to inform future recommendations in delivering against contemporary best practice, guidance and policy. A survey exploring the views and experiences of service users and prescribers on shared and supported decision-making in medication was carried out in West London NHS Trust. Questionnaires were fully co-designed and co-delivered by a group of health professionals and individuals with lived experience. There were 100 responses from service users and 35 from prescribers. There was some good practice where both parties reported good quality conversations concerning dialogic styles, collaborative process, information provided and range of choice offered. However, prescriber’s perception of their practice was not always mirrored by service user feedback whose experiences often depended upon the prescriber, the time available or the part of the service. Generally, service user experience fell short of the good practice cited by clinicians though there was noticeable variability. Commitment from organizations and increasing understanding from practitioners are vital in transforming SDM from rhetoric into reality. From our findings a further challenge is to ensure that prescribers and service users have the time, information and tools to implement it consistently.
Stability of planar rarefaction waves under general viscosity perturbation of the isentropic Euler system
Authors: Feireisl Eduard , Novotný Antonín
Published: February 2021

We consider the vanishing viscosity limit for a model of a general non-Newtonian compressible fluid in

R^{d}

,

d = 2,3

. We suppose that the initial data approach a profile determined by the Riemann data generating a planar rarefaction wave for the isentropic Euler system. Under these circumstances the associated sequence of dissipative solutions approaches the corresponding rarefaction wave strongly in the energy norm in the vanishing viscosity limit. The result covers the particular case of a linearly viscous fluid governed by the Navier–Stokes system.
Source and antibiotic susceptibility of gram-negative bacteria causing superficial incisional surgical site infections
Authors: Ali Kameran M. , Al-Jaff Bahrouz M.A.
Published: February 2021

ABSTRACT

Background:

Surgical site infections (SSIs) are a major public health problem worldwide and the second-most frequently reported type of nosocomial infection. The presence of Gram-negative bacteria (GNB) in the hospital environment is significantly associated with SSIs. As such, this study aimed to explore the rate, antibiotic profile and common sources of bacteria in SSI.

Methods:

A cross-sectional study was conducted between August 2018 and July 2019 in three surgical centers in Kalar city, Kurdistan region, Iraq. A total of 512 patients, who underwent surgery were followed up with for superficial incisional SSI. Pre-, intra- and postoperative swabs were collected from patients and the surrounding hospital environment and processed for isolation and identification of GNB by microbiological and molecular methods. The isolates were typed by sequencing and tested for antibiotic resistance using the disc-diffusion technique.

Results:

SSI developed in 113 (22.07%) of the patients studied. GNB were involved in 48 (9.38%) cases; among these, Klebsiella spp. were the predominant cause 21/48 (43.75%), followed by Escherichia coli 14/48 (29.17%), Pseudomonas aeruginosa 7/48 (14.58%), Enterobacter spp. 3/48 (6.25%) and A. baumannii 2/48 (4.17%). Citrobacter koseri showed the lowest rate of infection 1/48 (2.08%). Sequencing analysis and the antibacterial resistance profile revealed that 25 (74.28%) of the 48 SSI isolates were from the hospital environment, whereas the rest were exogenous, with an undetermined source. The involved GNB were highly resistant to most antibiotics tested.

Conclusion:

SSIs caused by GNB were mostly exogenous or from the hospital environment, not from endogenous sources. All of the bacterial isolates detected from SSI patients were multidrug resistant.

Highlights
Patient and public involvement in health technology assessment: update of a systematic review of international experiences
Authors: Gagnon Marie-Pierre , Tantchou Dipankui Mylène , Poder Thomas G. , Payne-Gagnon Julie , Mbemba Gisèle , Beretta Valentina
Published: February 2021

Objective

To summarize current evidence on patient and public involvement (PPI) in health technology assessment (HTA) in order to synthesize the barriers and facilitators, and to propose a framework to assess its impact.

Methods

We conducted an update of a systematic review published in 2011 considering the recent scientific literature (qualitative, quantitative, and mixed-methods studies). We searched papers published between March 2009 (end of the initial search) and December 2019 in five databases using specific search strategies. We identified other publications through citation tracking and contacting authors of previous related studies. Reviewers independently selected relevant studies based on prespecified inclusion and exclusion criteria. We extracted information using a pre-established grid.

Results

We identified a total of 7872 publications from the main search strategy. Ultimately, thirty-one distinct new studies met the inclusion criteria, whereas seventeen studies were included in the previous systematic review. PPI is realized through two main strategies: (i) patients and public members participate directly in decision-making processes (participation) and (ii) patients or public perspectives are solicited to inform decisions (consultation or indirect participation). This review synthesizes the barriers and facilitators to PPI in HTA, and a framework to assess its impact is proposed.

Conclusion

The number of studies on patients or public involvement in HTA has dramatically increased in recent years. Findings from this updated systematic review show that PPI is done mostly through consultation and that direct involvement is less frequent. Several barriers to PPI in HTA exist, notably the lack of information to patients and public about HTA and the lack of guidance and policies to support PPI in HTA.
Beyond Tools and Function: The Selection of Materials and the Ontology of Hunter-Gatherers. Ethnographic Evidences and Implications for Palaeolithic Archaeology
Authors: Assaf Ella , Romagnoli Francesca
Published: February 2021

In this paper we discuss the universal selection of exceptional materials for tool making in prehistory. The interpretation suggested in the literature for these non-standard materials is usually limited to a general statement, considering possible aesthetic values or a general, mostly unexplained, symbolic meaning. We discuss the implications of viewing these materials as active agents and living vital beings in Palaeolithic archaeology as attested in indigenous hunter-gatherer communities all around the world. We suggest that the use of specific materials in the Palaeolithic was meaningful, and beyond its possible ‘symbolic’ meaning, it reflects deep familiarity and complex relations of early humans with the world surrounding them—humans and other-than-human persons (animals, plants, water and stones)—on which they were dependent. We discuss the perception of tools and the materials from which they are made as reflecting relationships, respectful behaviour and functionality from an ontological point of view. In this spirit, we suggest re-viewing materials as reflecting social, cosmological and ontological world-views of Palaeolithic humans, and looking beyond their economic, functional aspects, as did, perhaps, our ancestors themselves.
The Elephant in the Handaxe: Lower Palaeolithic Ontologies and Representations
Authors: Barkai Ran
Published: February 2021

Indigenous hunter-gatherers view the world differently than do WEIRD (Western, Educated, Industrialized, Rich and Democratic) societies. They depend—as in prehistoric times—on intimate relationships with elements such as animals, plants and stones for their successful adaptation and prosperity. The desire to maintain the perceived world-order and ensure the continued availability of whatever is necessary for human existence and well-being thus compelled equal efforts to please these other-than-human counterparts. Relationships of consumption and appreciation characterized human nature as early as the Lower Palaeolithic; the archaeological record reflects such ontological and cosmological conceptions to some extent. Central to my argument are elephants and handaxes, the two pre-eminent Lower Palaeolithic hallmarks of the Old World. I argue that proboscideans had a dual dietary and cosmological significance for early humans during Lower Paleolithic times. The persistent production and use of the ultimate megaherbivore processing tool, the handaxe, coupled with the conspicuous presence of handaxes made of elephant bones, serve as silent testimony for the elephant–handaxe ontological nexus. I will suggest that material culture is a product of people's relationships with the world. Early humans thus tailored their tool kits to the consumption and appreciation of specific animal taxa: in our case, the elephant in the handaxe.
Memory Scrapers: Readymade Concepts and Techniques as Reflected in Collecting and Recycling Patinated Lower Palaeolithic Items at Qesem Cave, Israel
Authors: Efrati Bar
Published: February 2021

This paper argues that certain early Palaeolithic artefacts can be viewed as reflecting Readymade concepts and techniques from the world of modern art. I will focus on presenting a theoretical framework for this claim as well as a case study from Late Lower Palaeolithic Qesem Cave, Israel (420,000–200,000 bp). The case study is based on the ‘double patina’ phenomenon (old tools that became patinated by exposure to the elements and were then shaped again). These items, characterized by outstanding colours and textures, were produced following Readymade concepts and techniques applied in the production of tools that are both functional and mnemonic. I suggest that these items acted as mnemonic memory tools that reconnected their users to ancestral (human and non-human) beings as well as to familiar experiences, events, and places.
Changes in Raw Material Selection and Use at 400,000 Years bp: A Novel, Symbolic Relationship between Humans and Their World. Discussing Technological, Social and Cognitive Arguments
Authors: Romagnoli Francesca
Published: February 2021

Approximately 400,000 years bp, novel technological behaviours appeared in the archaeological record, attested by evidence of the exploitation of previously unused resources and the production of new tools. I have reviewed such innovations, and I discuss them in the frame of the anthropological, palaeoneurological, genetic and behavioural changes that appeared in the Middle Pleistocene. I propose that at this chronology humans started to see the resources as ‘other-than-human’ sentient co-dwellers. The technological innovations expressed this novel cognitive complexity and the possible new things–things, human–things and environment–things relationships. Artefacts and technologies acquired multiple semiotic meanings that were strongly interconnected with the functional value. Ethnoarchaeological evidence suggested the possible symbolic acting beyond these innovations in material culture. This perspective has relevant implications in the archaeology of the ancient Palaeolithic. It suggests the need for a new view of material culture, one that goes beyond the classical list approach in the definition of modern symbolic mediated behaviour. Further, it allows one to overcome the traditional juxtaposition between ancient cultures and Homo sapiens in terms of complexity. The evidence discussed in this paper suggests that the ontological hypothesis could change our view of Middle Pleistocene hominids and the origin and definition of modern behaviour, and test the archaeological visibility of cognition in prehistory.
Gymea and the Fishing Technologies of the New South Wales Coast, Australia
Authors: Freeman Clive , Freeman Julie , Langley Michelle C.
Published: February 2021

Stories are important to all modern peoples, and this behaviour was no doubt also the case during the deep past. Consequently, it is important that archaeologists understand that artefacts made and discarded thousands of years ago were woven with stories by the peoples who produced them. In some regions of the world, these stories remain accessible by collaborating with the Traditional Owners of the lands from which they were recovered, while in others such an approach is impossible. Nevertheless, researchers need to remember that items carried meaning usually invisible to those outside communities—a principle often taught and cited, but possibly not fully appreciated. Here we tell the Yuin (coastal New South Wales, Australia) story of Gymea and her connection to fishing technologies. This story is told in order to demonstrate the depth of information that is not accessible to archaeologists if Indigenous collaborators are not sought out or available.
EVIDENCE OF THE PRACTICAL APPLICATION OF SOLFEGGIO PATTERNS IN THE MANUSCRIPT FOR THE 1707 NEAPOLITAN PERFORMANCE OFLA FEDE TRADITA E VENDICATABY GASPARINI AND VIGNOLA
Authors: BOARO ERIC
Published: February 2021

The last two decades have seen the opening of several new paths in eighteenth-century musicology, and Robert O. Gjerdingen has opened one of these: schema theory. Schemata are ‘stock musical phrases employed in conventional sequences’ that function as harmonic, melodic and rhythmic frameworks for musical passages. Evidence of such schematic thinking has emerged through related studies on partimento and solfeggio. Solfeggio practice of the time manifests a schematic way of thinking about music, being mostly based on simple hexachordal patterns which, as studies progressed, could be embellished in different ways. Vasili Byros has addressed the ‘archaeology’ of hearing through reception history, and offered strong evidence that eighteenth-century ears did hear schemata. Interweaving corpus studies on music of the long eighteenth century (1720–1840), contemporary music criticism and reception history, as well as didactic documents from that era, Byros sheds new light on the ways in which schemata were perceived at the time. A recent contribution by Gilad Rabinovitch uses a live improvisation in the style of Mozart by Robert Levin to demonstrate the importance of conventional schemata for historical improvisation.
Beliefs about Language Learning: Students and Their Teachers at Arabic Programs Abroad
Authors: Kuntz Patricia
Published: February 2021

The U.S. public holds certain beliefs to be self-evident about language learning: To learn a foreign language, one must study abroad. Since World War I and especially after World War II, students of French, German, or Spanish have enrolled in junior year, semester, or summer language programs in Europe. Educators have suggested that by studying the targeted language in an immersion setting, U.S. students gain a higher proficiency than students might acquire with only stateside instruction.
Ethnicity and power in the mental health system: experiences of white British and black Caribbean people with psychosis
Authors: Lawrence V. , McCombie C. , Nikolakopoulos G. , Morgan C.
Published: February 2021

Aims

Persistent inequalities exist in how individuals from minority ethnic groups access mental health care. A failure to investigate how these inequalities are experienced and what they mean to people with psychosis has privileged professional narratives and hindered our understanding of how they are sustained and what could be done to reduce them. The aim of this study was to investigate the long-term experience of living with psychosis and navigating mental health services within different ethnic groups.

Method

Our approach was informed by work on narrative analysis and prioritised the meaning that mental health services held for participants. In-depth interviews with 17 black Caribbean, 15 white British and 3 non-British white people with psychosis as part of AESOP-10, a 10-year follow-up of an ethnically diverse cohort of individuals with first-episode psychosis in the UK. Thematic narrative analysis was used to examine experiences at the personal level within and then across the individual accounts.

Results

Service users shared many defining experiences and narratives frequently returned to individuals' first contact with mental health services, first hospital admission, the experience of impatient wards, and the meaning of medication and diagnosis in their lives. We found that experiences of powerlessness punctuated the journey through mental health services and this appeared to dominate the accounts of black Caribbean, and to a lesser extent, white British participants. The findings reveal how negative expectations and experiences of mental health services are compounded over time, creating a vicious cycle of disempowerment and mistrust that manifests for many in resistance to – or at the best passive acceptance of – intervention by mental health services. High levels of need, coupled with alienation from services, contributed to negative patterns of service use among black Caribbean participants. White participants recounted substantial, though fewer, experiences of disempowerment and more instances of shared decision making that for some helped protect positive aspects of their lives.

Conclusions

Against a background of entrenched social and economic disempowerment, services were experienced as disempowering by many black Caribbean people, compounding and perpetuating a sense of alienation. Concerted efforts by services to more systematically target social needs and to share power through partnership working may reduce the mistrust that many with psychosis feel when entering services and in turn reduce persistent inequalities across ethnic groups.
From Feedback Seeking to Psychological Attachment, the Mediating Role of Adaptive Performance in Perceived Obstruction Context
Authors: Déprez Guillaume R. M. , Bazine Nicolas , Fréour Léa , Peña-Jimenez Marco , Cangialosi Nicola , Battistelli Adalgisa
Published: February 2021

Based on proactivity literature, feedback seeking behavior is generally used throughout an individual’s career to enable better adaptation to the work environment. However, it has recently been shown that declining levels of feedback seeking behavior may result in decreased psychological attachment over time. This study aims to explore whether individual adaptivity represents a mechanism through which feed-back seeking affects psychological attachment (i.e., well-being involvement and withdrawal). In addition, the interaction effect of organizational obstruction between individual adaptivity and psychological attachment was examined. Based on three-wave survey data obtained from 273 participants from French organizations, a moderated mediation model was tested using structural equation modeling. Results confirmed that adaptive performance mediated positively the relationship between feedback-seeking and well-being involvement and negatively with withdrawal. Moreover, perceived organizational obstruction moderated negatively the relationship between adaptive performance and withdrawal, and positively that with well-being. These results shed new light on the relationship between proactivity (i.e., feedback seeking behavior) and adaptive performance, but also on the positive short-term contribution of successful adaptation in a perceived obstructive organizational context. Theoretical contributions and practical implications for human resource management are discussed.
Can Modeling the Geologic Record Contribute to Constraining the Tectonic Source of the 1755 CE Great Lisbon Earthquake?
Authors: Dourado F. , Costa P. J. M. , La Selle S. , Andrade C. , Silva A. N. , Bosnic I. , Gelfenbaum G.
Published: February 2021

The precise location of the seismic source of 1755 CE Great Lisbon earthquake is still uncertain. The aim of this work is to use an onland sedimentary record in southern Portugal to test and validate seismic sources for the earthquake. To achieve this, tsunami deposit thicknesses from over 150 cores collected at Salgados in southern Portugal were compared to the results of a tsunami sediment transport model (Delft3D‐FLOW) that simulates tsunami propagation, inundation, erosion, and deposition. Five different hypothetical seismic sources were modeled with varying bed roughness coefficients to assess how well they reproduced observed patterns of tsunami deposit thicknesses and dune. Modeled and observed historical tsunami arrival times were also used to test different earthquake sources. Based on these comparisons, three modeled earthquake sources were able to reproduce the observed data, suggesting they should be regarded as somewhat more likely sources for the 1755 earthquake in contrast to four other modeled sources. The fault closest to shore (Marquês de Pombal) yielded the best correlations between model and observations.
An Adaptive Method for Nonlinear Sea Level Trend Estimation by Combining EMD and SSA
Authors: Jin Taoyong , Xiao Mingyu , Jiang Weiping , Shum C. K. , Ding Hao , Kuo Chung‐Yen , Wan Junkun
Published: February 2021

Adaptive and accurate trend estimation of the sea level record is critically important for characterizing its nonlinear variations and its study as a consequence of anthropogenic climate change. Sea level change is a nonstationary or nonlinear process. The present modeling methods, such as least squares fitting, are unable to accommodate nonlinear changes, including the choice of a priori information to help constrain the modeling. All these problems affect the accuracy and adaptability of nonlinear trend estimation. Here, we propose a method called EMD‐SSA, that effectively combines adaptive empirical mode decomposition (EMD) and singular spectrum analysis (SSA). First, the sea level change time series is decomposed by EMD to estimate the intrinsic mode functions. Second, the periodic or quasiperiodic signals in the intrinsic mode functions can be determined using Lomb‐Scargle spectral analysis. Third, the numbers of the identified periodicities/quasiperiodicities are used as embedding dimensions of SSA to identify possible nonlinear trends. Then, the optimal nonlinear trend with the largest absolute Mann‐Kendall rank is selected as the final trend for the sea level change. Based on a comprehensive experiment using simulated sea level change time series, we concluded that the EMD‐SSA method can adaptively provide better estimate of the nonlinear trend in a realistic sea level change time series with consistency or high accuracy. We suggest that EMD‐SSA can be used not only to robustly extract nonlinear trends in sea level data, but also for trends in other geodetic or climatic records, including gravity, GNSS observed displacements, and altimetry observations.
Tropical Cyclone Characteristics in the MERRA‐2 Reanalysis and AMIP Simulations
Authors: Aarons Zoe S. , Camargo Suzana J. , Strong Jeffrey D. O. , Murakami Hiroyuki
Published: February 2021

This study evaluates the tropical cyclone (TC) activity in two high‐resolution data sets—MERRA‐2 Reanalysis (Modern‐Era Retrospective Analysis for Research and Applications, Version 2) and MERRA‐2 AMIP (Atmospheric Model Intercomparison Project). These data sets use the same atmospheric model, the Goddard Earth Observing System Model, Version 5 (GEOS‐5) during the same period. However, while MERRA‐2 AMIP is a free‐running atmospheric simulation forced only with sea surface temperature (SST), MERRA‐2 Reanalysis uses an advanced data assimilation system to include a large variety of data sets. Thus, we analyze (1) the sensitivity of TC activity to the model forcing, (2) how well the TCs in both data sets replicate observed TC characteristics, (3) the sensitivity of these results to tracking schemes and thresholds. Standard diagnostics such as the number of tropical cyclones and their intensity distribution are very similar in the AMIP model and the reanalysis. TCs in both data sets are weaker than observed, as is typical for the spatial resolution of these global models. Overall, the use of data assimilation in the MERRA‐2 Reanalysis does not lead to a significantly better TC climatology than in AMIP. Furthermore, comparison of the MERRA‐2 Reanalysis to two other reanalysis data sets shows that MERRA‐2 generates fewer, but more intense TCs, than those reanalysis products.
Assessment of ICESat‐2 Sea Ice Surface Classification with Sentinel‐2 Imagery: Implications for Freeboard and New Estimates of Lead and Floe Geometry
Authors: Petty A. A. , Bagnardi M. , Kurtz N. T. , Tilling R. , Fons S. , Armitage T. , Horvat C. , Kwok R.
Published: February 2021

NASA's Ice, Cloud, and Land Elevation Satellite‐2 (ICESat‐2) mission launched in September 2018 and is now providing high‐resolution surface elevation profiling across the entire globe, including the sea ice cover of the Arctic and Southern Oceans. For sea ice applications, successfully discriminating returns between sea ice and open water is key for accurately determining freeboard (the extension of sea ice above local sea level) and new information regarding the geometry of sea ice floes and leads. We take advantage of near‐coincident optical imagery obtained from the European Space Agency (ESA) Sentinel‐2 (S‐2) satellite over the Western Weddell Sea of the Southern Ocean in March 2019 and the Lincoln Sea of the Arctic Ocean in May 2019 to evaluate the surface classification scheme in the ICESat‐2 ATL07 and ATL10 sea ice products. We find a high level of agreement between the ATL07 (specular) lead classification and visible leads in the S‐2 imagery in these two coincident images across all six ICESat‐2 beams, increasing our confidence in the freeboard products and deriving new estimates of the sea ice state. The S‐2 overlays provide additional, albeit limited, evidence of the misclassification of dark leads due to clouds. Dark leads are no longer used to derive sea surface and thus freeboard as of the third release (r003) of the ICESat‐2 sea ice products. We show estimates of lead fraction and more preliminary estimates of chord length (a proxy for floe size) using two metrics for classifying sea surface (lead) segments across both the Arctic and Southern Ocean for the first winter season of data collection.
Cascading Hazards in the Aftermath of Australia's 2019/2020 Black Summer Wildfires
Authors: Kemter M. , Fischer M. , Luna L. V. , Schönfeldt E. , Vogel J. , Banerjee A. , Korup O. , Thonicke K.
Published: February 2021

Following an unprecedented drought, Australia's 2019/2020 “Black Summer” fire season caused severe damage, gravely impacting both humans and ecosystems, and increasing susceptibility to other hazards. Heavy precipitation in early 2020 led to flooding and runoff that entrained ash and soil in burned areas, increasing sediment concentration in rivers, and reducing water quality. We exemplify this hazard cascade in a catchment in New South Wales by mapping burn severity, flood, and rainfall recurrence; estimating changes in soil erosion; and comparing them with river turbidity data. We show that following the extreme drought and wildfires, even moderate rain and floods led to undue increases in soil erosion and reductions in water quality. While natural risk analysis and planning commonly focuses on a single hazard, we emphasize the need to consider the entire hazard cascade, and highlight the impacts of ongoing climate change beyond its direct effect on wildfires.
Impacts of Global Solid Biofuel Stove Emissions on Ambient Air Quality and Human Health
Authors: Huang Yaoxian , Partha Debatosh B. , Harper Kandice , Heyes Chris
Published: February 2021

Global solid biofuel stove emissions strongly impact air quality, climate change, and human health. However, investigations of the impacts of global solid biofuel stove emissions on human health associated with PM2.5 (particulate matter with aerodynamic diameter ≤2.5 μm) and ozone (O3) are limited. Here, we quantify the impacts of global solid biofuel stove emissions on ambient PM2.5 and O3 air quality and the associated human health effects for the year 2010, using the Community Atmosphere Model coupled with Chemistry version 5.3. Annual mean surface PM2.5 concentrations from global solid biofuel stove emissions averaged over 2006–2010 are up to 23.1 μg m−3, with large impacts found over China, India, sub‐Saharan Africa, and eastern and central Europe. For surface O3 impacts, we find that global solid biofuel stove emissions lead to increases in surface O3 concentrations by up to 5.7 ppbv for China, India, and sub‐Saharan Africa, and negligible impacts or reductions of up to 0.5 ppbv for the US, Europe, and parts of South America. Global solid biofuel stove emissions for the year 2010 contribute to 382,000 [95% confidence interval (95CI): 349,000–409,000] annual premature deaths associated with PM2.5 and O3 exposure, with the corresponding years of life lost as 8.10 million years (95CI: 7.38–8.70 million years). Our study highlights air quality and human health benefits of mitigating emissions from the global solid biofuel stove sector, especially over populous regions of low‐income and middle‐income countries, through promoting clean household energy programs for the residential energy supply.
Importance of Uncertainties in the Spatial Distribution of Preindustrial Wildfires for Estimating Aerosol Radiative Forcing
Authors: Wan J. S. , Hamilton D. S. , Mahowald N. M.
Published: February 2021

Uncertainty in preindustrial aerosol emissions, including fires, is one of the largest sources of uncertainty in estimating anthropogenic radiative forcing. Here, we quantify the range in aerosol forcing associated with uncertainty in the location and magnitude of preindustrial fire emissions in a climate model based on four emission estimates. With varied emission location and magnitude among the fire estimates, we find the change in aerosol forcing from present‐day to preindustrial is between −0.4 and 0.3 W/m2 for direct radiative forcing and between −1.8 and 0.6 W/m2 for cloud albedo forcing. Altering only the spatial distribution of preindustrial fires for a fixed magnitude adds a previously unaccounted 25% uncertainty to the total aerosol radiative forcing range. Future studies must account for the uncertainty in the spatial distribution of fire and other aerosol emissions as regional differences contribute substantial additional uncertainty to anthropogenic radiative forcing estimates and the resultant climate sensitivity.
Modeling Plant Roots Spectral Induced Polarization Signature
Authors: Tsukanov Kuzma , Schwartz Nimrod
Published: February 2021

Monitoring the growth, architecture, and function of plant roots is of great interest. One promising noninvasive geoelectrical monitoring approach is spectral induced polarization (SIP). However, the roots' SIP signature is underexplored, not well understood, and a mechanistic model has not been proposed. Here, we developed a mechanistic model for SIP's response of roots, which is based on the Poisson‐Nernst‐Planck equation. The modeling results suggest that the magnitude of root polarization is linearly related to the root's external surface area and that the polarization length scale is the root's diameter. We suggest that injecting a current to the plant's stem results in higher polarization associated with the root‐cells' total surface area. In this case, the polarization length scale is the cell diameter. Overall, we quantified the link between the root's dimensions and their electrical signature, which may inspire SIP application for root phenotyping.
Gulf Stream Mean and Eddy Kinetic Energy: Three‐Dimensional Estimates From Underwater Glider Observations
Authors: Todd Robert E.
Published: February 2021

The strong, meandering, and eddy‐shedding Gulf Stream is a large oceanic reservoir of both mean and eddy kinetic energy in the northwestern Atlantic. Since 2015, underwater gliders equipped with Doppler current profilers have collected over 20,000 absolute velocity profiles in and near the Gulf Stream along the US East Coast. Those observations are used to make three‐dimensional estimates of mean and eddy kinetic energy, substantially expanding the geographic coverage of prior estimates of subsurface kinetic energy in the Gulf Stream. Glider observations are combined via weighted least squares fitting with anisotropic and inhomogeneous length scales to reflect both circulation and sampling density; this averaging technique can be applied to other quantities measured by the gliders. Mean and eddy kinetic energy decay approximately exponentially away from the surface. Vertical decay scales are longest within the high‐speed core of the Gulf Stream and somewhat shorter on the flanks of the Gulf Stream.
Evolution of Subtropical Pacific‐Onset El Niño: How Its Onset Location Controls Its Decay Evolution
Authors: Kim Ji‐Won , Yu Jin‐Yi
Published: February 2021

In the observations, El Niño events initiated by a subtropical Pacific mechanism (SP‐onset El Niños) show larger uncertainty in their decay evolution patterns than those initiated by a tropical Pacific mechanism. A 2,200‐year simulation of Community Earth System Model reproduces this observed feature and its SP‐onset El Niños are analyzed to understand the cause of the large uncertainty. Results show that the onset location of SP‐onset El Niño, which interacts with the eastern edge of the western Pacific warm pool, is a key factor controlling its decay evolution. When the onset is located east (west) of 155°E, the event has a strong tendency to reverse (maintain) its phase, leading to cyclic (multiyear) evolution. These two onset locations respectively activate Indo‐Pacific and tropical‐subtropical Pacific interactions to give rise to the different evolution patterns. The findings offer a potential way to predict the evolution of SP‐onset El Niños using their onset locations.
Ocean Acidification Reduces Skeletal Density of Hardground‐Forming High‐Latitude Crustose Coralline Algae
Authors: Williams B. , Chan P. T. W. , Westfield I. T. , Rasher D. B. , Ries J.
Published: February 2021

Crustose coralline algae (CCA) function as foundation species by creating marine carbonate hardground habitats. High‐latitude species may be vulnerable to regional warming and acidification. Here, we report the results of an experiment investigating the impacts of CO2‐induced acidification (pCO2 ∼350, 490, 890, 3,200 µatm) and temperature (∼6.5°C, 8.5°C, 12.5°C) on the skeletal density of two species of high‐latitude CCA: Clathromorphum compactum and Clathromorphum nereostratum (CN). Skeletal density of both species significantly declined with pCO2. In CN, the density of previously deposited skeleton declined in the highest pCO2 treatment. This species was also unable to precipitate new skeleton at 12.5°C, suggesting that CN will be particularly sensitive to future warming and acidification. The decline in skeletal density exhibited by both species under future pCO2 conditions could reduce their skeletal strength, potentially rendering them more vulnerable to disturbance, and impairing their production of critical habitat in high‐latitude systems.
Auroral Energy Flux and Joule Heating Derived From Global Maps of Field‐Aligned Currents
Authors: Robinson R. M. , Zanetti L. J.
Published: February 2021

We calculate auroral energy flux and Joule heating in the high‐latitude ionosphere for 27 geomagnetically active days using two‐dimensional maps of field‐aligned currents determined by the Active Magnetosphere and Planetary Response Experiment. The energy input to the ionosphere due to Joule heating increases more rapidly with geomagnetic activity than that due to precipitating particles. The energy flux varies more smoothly with time than Joule heating, which is impulsive in nature on time scales from minutes to tens of minutes. These impulsive events correlate well with recoveries in the Sym‐H index, with the maximum correlation when compared to Sym‐H recoveries 70 min later. Because of prior studies that have associated transient recoveries of Sym‐H with substorm expansions, the delay found here suggests that dissipation of energy in the ionosphere occurs during the substorm growth phase prior to the release of magnetic energy caused by diversion of tail currents.
Lower Surface Temperature at Bright Ephemeral Feature Site on Titan's North Pole
Authors: Dhingra Rajani D. , Jennings Donald E. , Barnes Jason W. , Cottini Valeria
Published: February 2021

We report a temperature difference in one of the regions on Titan that is, documented as a bright ephemeral feature (BEF). Spectra were recorded by Cassini's Composite Infrared Spectrometer. BEFs are 5 µm bright areas that appear, disappear, and shift from flyby to flyby at Titan's North Pole observed in Visual and Infrared Mapping Spectrometer (VIMS) data. They are inferred to be broad‐specular reflections caused by a smooth surface on Titan or a near surface fog—both of which indicate that the atmosphere interacted with the surface. We used 24 spectra for “on the BEF” and 51 spectra for “off the BEF” region to determine the temperature difference during the T121 flyby (July 25, 2016). At the 410–560 cm−1 window where surface emissions are perceptible we see a decrease in temperature by 1.2 ± 0.2 K. This decrease in temperature might indicate precipitative cooling after a fresh rainfall on Titan's land/sea surface.
Seismic and Aseismic Fault Slip During the Initiation Phase of the 2017 MW = 6.9 Valparaíso Earthquake
Authors: Caballero Emmanuel , Chounet Agnès , Duputel Zacharie , Jara Jorge , Twardzik Cedric , Jolivet Romain
Published: February 2021

Transient deformation associated with foreshocks activity has been observed before large earthquakes, suggesting the occurrence of a detectable preseismic slow slip during the initiation phase. A critical issue consists in discriminating the relative contributions from seismic and aseismic fault slip during the preparation phase of large earthquakes. We focus on the April–May 2017 Valparaíso earthquake sequence, which involved a MW = 6.9 earthquake preceded by intense foreshock activity. To assess the relative contribution of seismic and aseismic slip, we compare surface displacement predicted from foreshocks source models with transient motion measured prior to the mainshock. The comparison between observed and predicted displacements shows that only half of the total displacement can be explained by the contribution of foreshocks. This result suggests the presence of aseismic pre‐slip during an initiation phase preceding the mainshock.