bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Private Shopping Sites With User Data From Entropy-Based Moosra Method
Authors: Kılıç Günay , Organ Arzu
Published: April 2019

The share of electronic commerce (e-commerce) in total trade is increasing. There are many kinds of services and products within the scope of e-commerce. These products and services are subdivided according to their sales forms and product groups. In this chapter, only the private shopping websites in the online sales group were examined. Private shopping sites are the sites where the members buy certain products with limited stock in limited time. In this chapter, six leading sites are defined as alternatives for the purpose of comparison. When the studies in the literature are examined, it is seen that multi-criteria decision making methods are used in order to sort the special shopping sites by taking into consideration the criteria. Entropy method was used to determine the weights of the criteria under each main topic determined in the study. Moosra method was chosen from multi-criteria decision making methods in order to rank alternative websites. As a result, alternative sites were listed separately and then examined as to whether there was a relationship between these groups.
ERP Software Selection Based on Intuitionistic Fuzzy VIKOR Method
Authors: Efe Burak
Published: April 2019

This chapter uses intuitionistic fuzzy VIKOR (IFVIKOR) for the application of ERP software selection. First, priority values of criteria in ERP software selection problem have been determined by using the judgments of the experts. IFWA operator is utilized to integrate the judgments of the experts about the weights of criteria. Then, the result of the IFVIKOR can be employed to define the most appropriate ERP alternative in uncertain environment. Intuitionistic fuzzy numbers are presented in all phases in order to overcome any vagueness in the decision-making process. The final decision depends on the degree of importance of each decision so that wrong degree of importance causes the mistaken result. The researchers generally determine the degrees of importance of each decision makers according to special characteristics of each decision maker as subjectivity. In order to overcome this subjectivity in this chapter, the judgments of decision makers are degraded to unique decision by using the importance degree of each expert. There is no study about ERP software selection using IFVIKOR.
Process of Placing Advertisements on Website Homepage
Authors: Kalia Gitanjali
Published: April 2019

We cannot find any website without advertisements on it. As the number of websites has increased enormously, marketers are trying every niche to target the consumers. While designing a website, a lot of elements are kept in mind. Type of website, ad layout opted, type of internet ad, duration, and position of the ad on the website will be discussed. As the research is based on Harold Laswell model of communication (i.e., who says what, to whom, which channel, and with what effect), the role of the marketers and the way the message is communicated to the online consumers will be discussed. Earlier researches done under this topic will be discussed so as to understand the scope of the research conducted and model suggested. The chapter will include the model suggested at the end of the research and how the basic model of communication by Harold Laswell has diversified over a period of time.
Popular Culture and Media Intellectuals
Authors: Arık Emel
Published: April 2019

This chapter aims at investigating the relationship between popular culture, the recently dominant culture, and media intellectuals. Popular culture can be defined as daily practices preferred widely by the people. In fact, the term popular culture stems from the word, people, in English. Thus, it refers to a unification of supra-class experience of the majority. Due to its specific characteristics, popular culture stems from culture, mass, high, and folk culture, but it also reflects a more independent and common culture. It is modern, civic, entertaining, and close to consumption. It is also based on dominant values. Therefore, recent intellectuals, whom we cannot think apart from the media, play a significant role in the reproduction of popular culture. Those media intellectuals, a new and defining class, are fed from the popular culture and also contribute to widen this culture among masses. Media intellectuals are primary focal points affecting the system in terms of both consumption culture, daily life, and popular politics. Thus, one of the main actors of popular culture is media intellectuals. Such concepts and the relationships among them will be discussed in this study along with their daily examples, and the role of media intellectuals in reproducing popular culture will be analyzed by means of literature review.
The Effect of Popular Culture on TV Program Genres Within Globalization Process
Authors: Ersin Nimet
Published: April 2019

In the process of globalization, popular culture has spread all around the world far more easily via television. Following 1980s, commercial televisions increasing together with the dominance of liberal economy have operated in accordance with commercial logic, and therefore, television programs have been produced for upper ratings, accordingly for getting high advertisement profits. Together with globalization, television programs have rather focused on entertainment. Popular culture has influenced programme genres both in terms of making existing programs entertaining and emerging novel amusing program genres. In this chapter, following the discussions on popular culture, the increase in entertainment in television programs is generally discussed, and then, the increase in entertainment in television programs in Turkey in the process of globalization is analyzed.
Multiculturalism in Cinema in the Context of Popular Culture
Authors: Arisoy Eda
Published: April 2019

The presentation of what the viewer wants and expects has turned cinema into a mass consumer industry, spreading into a universal space. Cinema is not merely to please the masses, but has been transformed into a multicultural business that carries a different intellectual meaning which is named as narrative or auteur cinema. As an auteur director, Ferzan Özpetek stands in highly unique place in the name of cultural wealth as a director. His cinema draws up in the thin line between being a popular cultural product and being a narrative, spiritual cinema product, and is considered as the most important feature that differentiates the concept of auteur from other cinema genres by focusing on the cultures of both countries. If the cinema industry returns to a differentiation between commercial and narrative types, film should create its audience by presenting its own cultural heritage, rather than exposing the same culture to the masses. It is the factor that nourishes the cultural variety.
Black Lives Matter vs. All Lives Matter in the Generation of “Hashtivism”
Authors: Campbell Danella May
Published: April 2019

This chapter investigates the hashtag battle #BlackLivesMatter vs. #AllLivesMatter and considers its ability to promote cyber race. It assesses the implications of constructing racial boundaries within the online space, its impact on identity politics and the viability for cyberspace to exist as a post-racial epoch in the digital age. This study takes an affordance and architectural approach to its analysis of BLM and ALM, incorporating a thematic analysis of the hashtags on Twitter. The research uses a theoretical underpinning of framing theory to analyze tweets from the ALM and BLM twitter timelines. It demonstrates that the hashtag battle, although, configured, and framed by the mainstream media as one that encapsulates a race war of Black vs. White, that actually, findings reveal that the battle consists of the tension and friction between mainstream media frames and what is termed digitized frames.
Self-Laundering for Marketing
Authors: Ozgen Pelin
Published: April 2019

In today's world, consumption brings contentment. Consumers are glad, thinking themselves as being wealthier and more prominent by buying and consuming more, whereas companies are delighted with the increased profitability resulted by higher production levels. However, given the data on economic and social inequalities in addition to environmental resources which are coming to an end, the happiness cannot continue forever. Therefore, in this chapter, the role of marketing in the formation of consumption culture and the concept of sustainability are reviewed. Moreover, the interaction between marketing and sustainability and what these two concepts can offer for each other is discussed. To guide the companies in forming sustainability strategies, practices of respectable and pioneer companies that are included in the Guardian's “Best Sustainability Practices in Business List” are presented.
An Application of CAMELS and Z-Score Methodologies in a Comparative Analysis Between the Four Systemic Banks in Greece for the Period 2006-2016
Authors: Christopoulos Apostolos G.
Published: April 2019

Τhe recent crisis which accelerated after the collapse of Lehman Brothers in 2008 revealed that relationships between the real economy and the financial sector are decisive for the stability of the world economy, even in in cases of well operating banking systems operating in competitive economies. In the present article, the authors focus on Greece, the weakest member of the Eurozone, but with a financial system which seemed to operate on a sound basis, avoiding initially the effects of the US financial crisis. The goal of this article is to examine the performance of the Greek banking sector for the critical decade before and after the crisis, assessing the financial position of the four systemic Greek banks for the period 2006-2016. For this purpose, two alternative methods, CAMELS and Z-scores, are applied, comparing the results obtained from the two methodologies. As expected, the results of both methodologies show that the failure risk during the crisis period 2011-2016 for the four systemic banks was significantly higher compared to the pre-crisis period 2006-2010.
Human Linguistic Perception of Distances for Location-Aware Systems
Authors: Olowolayemo Akeem , Mantoro Teddy
Published: April 2019

Location referencing relative to landmarks or between two points of interest is often presented by navigation systems (e.g., GPS, Google Maps) in quantitative terms (e.g., 100m, 2km, etc.). However, humans refer to distances between points of interests in linguistic forms, such as very close, far, almost there, nearby, etc. When location information is presented to humans in quantitative terms, they often reprocess the quantities into linguistic terms and articulate it in linguistic labels because quantitative articulations are not directly in line with the natural human cognition. Therefore, this research seeks to evaluate the possibility of applying perceptive computing to reprocess quantitative location references from landmarks or two points of interest into linguistic labels easily understood by humans. A comparative analysis between the perception of quantitative distances and similar physical distances in an environment familiar to the subjects has been carried out, and there is a clear disparity between the perceptions in these two contexts.
Exploring Novel Strategies for Lipid-Based Drug Delivery
Authors: Kotta Sabna , Sharma Navneet , Raturi Prateek , Aleem Mohd , Sharma Rakesh Kumar
Published: April 2019

Currently, the concept of lipid-based drug delivery systems has gained much interest because of their capability to deliver drugs which dissolve sparingly in water or insoluble in nature. Several methods of lipid-based drug delivery exist, and each method has its own advantages as well as limitations. The primary objective of the formulation development is to improve the bioavailability of the drug. The nano-sized lipid-based drug delivery systems have enough potential to do so. This article addresses the various barriers to the transportation of drugs through certain routes and also the common excipients which used to develop the lipid-based drug delivery systems. It provides a thorough overview of the lipid formulation classification scheme (LFCS) and also deals with several formulation & evaluation aspects of lipid-based drug delivery system. Further, it focuses on the formulations which are already available in the market and their regulatory concerns, respectively.
Aggregated Handover Authentication for Machine Type Communication
Authors: Chen Xin , Liu ZhiQiang , Wan Jianxiong , Li Zhuo
Published: April 2019

Nowadays, the technology of internet of things is developing rapidly, and the application of machine type communication (MTC) is becoming more and more extensive. Meanwhile, the 3rd generation partnership project (3GPP) organization proposes a standard architecture for MTC in LTE-A networks. However, when a large number of MTC devices handover authentication at the same time, the use of 3GPP handover mechanisms takes up more signaling resources, which will cause signaling congestion and vulnerable attacks. To solve this problem, the researchers propose an aggregated handover authentication protocol for MTC in LTE-A networks. Compared with the current 3GPP standards, the scheme can not only avoid signaling congestion, but also support more security. Finally, the researchers use colored petri nets (CPN) to model and analyze the proposed protocol. Simulation results show that the protocol is secure and achievable.
A Study on Satisfaction Level Among Amateur Web Application Developers Towards Pigeon-Table as Nano Web Development Framework
Authors: Ann Ong Chin , Tee Fu Swee , Nen Voon Yang
Published: April 2019

Web applications are an important platform in today's society, which humans rely on to complete daily tasks. Most of the web applications were developed with sophisticated, well-known, and powerful web development frameworks. While these frameworks evolve and grow at exponential rate, it become very complex, challenging to learn and no longer intuitive for web application developers, especially those who are inexperience and amateur. There is a need for a simpler web development framework which is sufficient for contemporary web application development. Pigeon-table is a simple module developed under ngPigeon project with the aim to generate web content, i.e. table using data from MySQL database with a single html tag. Pigeon-table is intuitive and easy to learn as it was developed with the principle “web developer-centred design” in mind. A pilot test was conducted in this study to evaluate the satisfactory level among amateur web application developers towards pigeon-table as nano-framework.
Effect of Electrode Coating on Austenitic Stainless Steel Weld Metal Properties
Authors: Anaele Justus Uchenna , Egole Chijioke Peter , Nzebuka Gaius Chukwuka , Nnodum Anthony Nnamdi
Published: April 2019

The effect of electrode coating on austenitic stainless steel weld metal properties was studied. Manual metal arc welding method was used to produce the joints with the tungsten inert gas welding serving as the control. Metallographic and chemical analyses of the fusion zones of the joints were conducted. Results indicate that the weldment produced from E 308-16/12 lime-titania electrode has a higher ductility and strength of about 36% in terms of percentage elongation and 517 N/mm2respectively, compared to 26% and 18% and 475 N/mm2and 425 N/mm2respectively, obtained from weldments produced from E 308-16/10 rutile and E 308-16/12 rutile electrodes respectively. The presence of lime which is a slag former in E 308-16/12 lime-titania electrode was relevant in slowing down the cooling rate of both the weld pool and the just solidified weld metal resulting in the overall improvement of the resultant weld metal properties. It was found that the values of the strain hardening exponent were 0.379 for E 308-16 gauge 10, rutile electrode, 0.406 for E 308-16 gauge 12 rutile electrode, 0.382 for TIG welding, 0.353 for E 308–16 gauge 12, lime-titania electrode, 0.435 for E 310-16 gauge 10, rutile electrode. E 310 – 16 gauge 10, rutile electrode had the greatest strength and strain hardening coefficients of 1180 N/mm2and 0.435 respectively, and will be more amenable to cold working. Keywords: Austenitic stainless steel, microstructure, electrode coating, welding, joints.
Parametric Sensitivity Analysis of Curing Deformation of Angle-Ply Fiber Metal Laminates
Authors: Che Lu , Zhang Jia Zhen , Zhao Yuan , Zu Shi Ming , Zhou Zhen Gong
Published: April 2019

In the process of studying the curing deformation behavior of fiber metal laminates (FMLs) subjected to thermal stress, there are some discrepancies between analytical models and experimental results for the room-temperature stable configuration. The main reason is the uncertainty of the parameters in the analytical calculation. In present paper, a parametric sensitivity analysis of the influence of Young’s modulus, Poisson’s ratio, thermal expansion coefficients, ply thickness, ply angle and temperature difference on the cured stable configuration is carried out to identify the most sensitive properties. Accurate characterization of these sensitive properties and precise control of manufacture process can reduce the discrepancies and obtain a more accurate prediction model. It is believed that the present study can be helpful of guiding the design and manufacture of the FMLs in the engineer application.
Investigating the Effect of Nanoclay Loadings and Re-Processing on the Melting and Crystallization Behavior of PP/Clay Nanocomposites
Authors: Chafidz Achmad , Ma'mun Sholeh , Haryanto  , Rengga Wara Dyah Pita , Handayani Prima A. , Setyaningsih Lucky
Published: April 2019

In this study, PP/clay nanocomposites have been fabricated at different nanoclay loadings, i.e. 0, 5, 10, and 5 wt% for the 1stcycle and 2ndcycle (re-processing). The prepared nanocomposites were then characterized by a Differential Scanning Calorimetry (DSC) to investigate the effects of nanoclay loadings and re-processing on the melting and crystallization of the nanocomposites. The DSC results showed that the melting temperature,Tmwas not significantly affected by the nanoclay loadings and re-processing. In the other hand, the degree of crystallinity,Xcof the nanocomposites was higher than that of neat PP, but only reached a maximum at nanoclay loading of 5 wt% (i.e. 51.2% for NC-5-I and 48.3% for NC-5-II). Thereafter, theXcdecreased at higher nanoclay loadings. There was no significant difference inXcbetween 1stcycle and 2ndcycle. Additionally, in all nanocomposites samples for both cycles, there were two crystallization temperatures, i.e.Tc1andTc2. In the overall crystallization process, theTcof nanocomposites increased by 11-12°C compared to that of neat PP. Whereas, the onset crystallization temperature,Tocalso increased by approx. 13°C. Apparently, there was no significant effect of nanoclay loadings and re-processing on theTcndTocof the nanocomposites.
An Experimental Study on Macro Piezoceramic Fiber Composites for Energy Harvesting
Authors: Khazaee Majid , Rezaniakolaei Alireza , Rosendahl Lasse
Published: April 2019

During the last decades, composite materials are being widely used in a variety of applications. Recently, a type of composite materials with piezoelectric fibers has been introduced for energy harvesting. This study presents an experimental study about composite materials with Piezoceramic fibers for energy harvesting. For this purpose, Macro Fiber Composite (MFC) layers were attached to the surface of metal substrates to form a unimorph harvester. In addition, to investigate the effect of substrate geometrical imperfection on output power, unimorph harvester with notched corners are studied. The output voltage and power were measured during different base excitations. Voltage frequency spectrum and output power as a function of load resistance are analyzed. Results show that the power density for the MFC harvester is 10.37 [μW/cm3.g2] when vibrating on its fundamental natural frequency with current of 50 [μA], which are relatively higher than previous studies.
Performance of Jute-Glass/Epoxy Composite Curved Laminate under Tensile Loading
Authors: Khalid Asad A.
Published: April 2019

In this paper, experimental work on the behavior of composite curved laminate subjected to flexural tensile loading was carried out. Woven roving [∓45] jute, jute-glass, glass-jute and glass/epoxy curved laminates were fabricated by hand lay-up molding. The curved laminate consists of a central circular 90° region connected with two straight arms. Curved laminate length, width and inner radius were 160 mm, 40 mm and 15 mm respectively. Two and four laminate layers were investigated under flexure tensile loading. Test fixture was fabricated to hold the free ends of the curved laminate during the loading process. Effect of stacking sequence, fiber type and number of layers on the tensile load-displacement relation, interlaminar tensile strength (ILTS) and failure mode were investigated. Results show that the maximum tensile load of the glass/epoxy curved laminate is found higher than the glass-jute, jute-glass followed by jute/epoxy curved laminate. Interlaminar tensile strength decreased with the increase in number of layers. The interlaminar tensile strength of glass/ epoxy curved laminate is found higher than the glass-jute, jute-glass followed by jute/epoxy curved laminates. Failure mode is influenced by the material type and number of layers. Increasing the number of layers from two to four leads to interlaminar fracture. Tension and compression fracture were observed respectively on the inner and outer layer of the central region of the curved laminates.
Electrolyte Effect to Copolymer Grafting of Starch onto Natural Rubber Using Glow Discharge Electrolysis Plasma (GDEP) Method
Authors: Agita Anisa , Diviva Bilal Islam , Alfiando Muhammad Abizar Yusa , Gufran Biran , Chalid Mochamad
Published: April 2019

Natural rubber has an important role in many applications such as tyre products due to excellent elasticity and high friction causing wear on the tire and leading to energy dissipation in the form of heat and noise. Although reinforcing both inorganic and organic fillers can be a solution, it generally needs expensive coupling agent. Finding an excellent coupling agent by considering to environmentally friendly materials and economic aspect, is an interesting study. This study reported modification of natural rubber through copolymer grafting of starch onto natural rubber latex using Glow Discharge Electrolysis Plasma (GDEP) with varying of electrolyte. The experimental indicated that the electrolytes generally give significant effect to percent yield of the hybrid natural rubber-starch product. The highest percent yield is obtained from adding KCl. Addition of the divalent salts such as MgCl2and CaCl2disturbs the process due to reaction the salts with stabilizing system in natural rubber latex. Addition of NaOH is able to enhance the reaction performance with considering the radical elements recombination. The starch part as polar part and the natural rubber as non polar part building up the hybrid natural rubber-starch products, correlate with hydrophilicity and degradation of the both parts. This study results in the lowest contact angle of 54.80, the highest percent yield of 8.6 %,, and the highest starch content in the product of 1.6%.
A remark about critical sets in $\mathbb R^3$
Authors: Souto Juan
Published: April 2019

We give a necessary condition for a subset of

\mathbb R^3

to be the set of critical points of some smooth function. In particular we obtain that for example neither the Whitehead continuum nor the p-adic solenoid are such critical sets.
Irreducible polynomials over finite fields produced by composition of quadratics
Authors: Heath-Brown David Rodney , Micheli Giacomo
Published: April 2019

For a set

S

of quadratic polynomials over a finite field, let

C

be the (infinite) set of arbitrary compositions of elements in

S

. In this paper we show that there are examples with arbitrarily large

S

such that every polynomial in

C

is irreducible. As a second result, when

\#S > 1

, we give an algorithm to determine whether all the elements in

C

are irreducible, using only

O( \#S(\log q)^3 q^{1/2} )

operations.
Development of a Simulation-Based Interprofessional Teamwork Assessment Tool
Authors: Bismilla Zia , Boyle Tehnaz , Mangold Karen , Van Ittersum Wendy , White Marjorie Lee , Zaveri Pavan , Mallory Leah
Published: April 2019

Background 

The Accreditation Council for Graduate Medical Education (ACGME) Milestone projects required each specialty to identify essential skills and develop means of assessment with supporting validity evidence for trainees. Several specialties rate trainees on a milestone subcompetency related to working in interprofessional teams. A tool to assess trainee competence in any role on an interprofessional team in a variety of scenarios would be valuable and suitable for simulation-based assessment.

Objective 

We developed a tool for simulation settings that assesses interprofessional teamwork in trainees.

Methods 

In 2015, existing tools that assess teamwork or interprofessionalism using direct observation were systematically reviewed for appropriateness, generalizability, adaptability, ease of use, and resources required. Items from these tools were included in a Delphi method with multidisciplinary pediatrics experts using an iterative process from June 2016 to January 2017 to develop an assessment tool.

Results 

Thirty-one unique tools were identified. A 2-stage review narrowed this list to 5 tools, and 81 items were extracted. Twenty-two pediatrics experts participated in 4 rounds of Delphi surveys, with response rates ranging from 82% to 100%. Sixteen items reached consensus for inclusion in the final tool. A global 4-point rating scale from novice to proficient was developed.

Conclusions 

A novel tool to assess interprofessional teamwork for individual trainees in a simulated setting was developed using a systematic review and Delphi methodology. This is the first step to establish the validity evidence necessary to use this tool for competency-based assessment.
Towards continuous monitoring of aerosol hygroscopicity by Raman lidar measurements at the EARLINET station of Payerne
Authors: Navas Guzmán Francisco , Martucci Giovanni , Collaud Coen Martine , Granados Muñoz María José , Hervo Maxime , Sicard Michael , Haefele Alexander
Published: April 2019

Abstract. This study focuses on the analysis of aerosol hygroscopicity using remote sensing technique. Continuous observations of aerosol backscatter coefficient, temperature and water vapour mixing ratio are performed by means of a Raman lidar system at the aerological station of MeteoSwiss at Payerne (Switzerland) since 2008. These measurements allow us to monitor in a continuous way any change of aerosol properties as a function of the relative humidity (RH). These changes can be observed either in time at constant altitude or in altitude at a constant time. The accuracy and precision of RH measurements from the lidar have been evaluated using the radiosonde (RS) technique as reference. A total of 172 RSs were used in this intercomparison which revealed a small bias (
The impact of bath gas composition on the calibration of photoacoustic spectrometers with ozone at discrete visible wavelengths spanning the Chappuis band
Authors: Cotterell Michael I. , Orr-Ewing Andrew J. , Szpek Kate , Haywood Jim M. , Langridge Justin M.
Published: April 2019

Abstract. Photoacoustic
spectroscopy is a sensitive in situ technique for measuring the absorption
coefficient for gas and aerosol samples. Photoacoustic spectrometer (PAS)
instruments require accurate calibration by comparing the measured
photoacoustic response with a known level of absorption for a calibrant.
Ozone is a common calibrant of PAS instruments, yet recent work by Bluvshtein
et al. (2017) has cast uncertainty on the validity of ozone as a calibrant at
a wavelength of 405 nm. Moreover,
Fischer and Smith (2018) demonstrate
that a low O2 mass fraction in the bath gas can bias the measured PAS
calibration coefficient to lower values for wavelengths in the range
532–780 nm. In this contribution, we present PAS sensitivity measurements
at wavelengths of 405, 514 and 658 nm using ozone-based calibrations with
variation in the relative concentrations of O2 and N2 bath
gases. We find excellent agreement with the results of Fischer and Smith at
the 658 nm wavelength. However, the PAS sensitivity decreases significantly
as the bath gas composition tends to pure oxygen for wavelengths of 405 and
514 nm, which cannot be rationalised using arguments presented in previous
studies. To address this, we develop a model to describe the variation in PAS
sensitivity with both wavelength and bath gas composition that considers
Chappuis band photodynamics and recognises that the photoexcitation of
O3 leads rapidly to the photodissociation products O(3P)
and O2(X, v > 0). We show that the rates of two
processes are required to model the PAS sensitivity correctly. The first
process involves the formation of vibrationally excited
O3(X̃) through the reaction of the nascent
O(3P) with bath gas O2. The second process involves the
quenching of vibrational energy from the nascent O2(X,
v > 0) to translational modes of the bath gas. Both of these
processes proceed at different rates in collisions with N2 or
O2 bath gas species. Importantly, we show that the PAS sensitivity is
optimised for our PAS instruments when the ozone-based calibration is
performed in a bath gas with a similar composition to ambient air and
conclude that our methods for measuring aerosol absorption using an
ozone-calibrated PAS are accurate and without detectable bias. We emphasise
that the dependence of PAS sensitivity on bath gas composition is
wavelength-dependent, and we recommend strongly that researchers characterise
the optimal bath gas composition for their particular instrument.
Full-azimuthal imaging-DOAS observations of NO2 and O4 during CINDI-2
Authors: Peters Enno , Ostendorf Mareike , Bösch Tim , Seyler André , Schönhardt Anja , Schreier Stefan F. , Henzing Jeroen Sebastiaan , Wittrock Folkard , Richter Andreas , Vrekoussis Mihalis , Burrows John P.
Published: April 2019

Abstract. A novel imaging-DOAS instrument (IMPACT) is presented combining full-azimuthal pointing (360°) with a large vertical coverage (~ 40°). Complete panoramic scans are acquired at a temporal resolution of ~ 15 minutes enabling the retrieval of NO2 vertical profiles over the entire panorama around the measurement site. IMPACT showed excellent agreement (correlation > 99 %) with coinciding MAX-DOAS measurements during the CINDI-2 campaign. The temporal variability of NO2 slant columns within a typical MAX-DOAS vertical scanning sequence could be resolved and was as large as 20 % in a case study under good viewing conditions. The variation of corresponding profiles and surface concentrations were even larger (40 %). This variability is missed when retrieving trace gas profiles based on standard MAX-DOAS measurements. The azimuthal distribution of NO2 around the measurement site showed inhomogeneities (relative differences) up to 120 % (on average 35 %) on short time scales (individual panoramic scans). This is more than expected taking into account the semi-rural location. One reason for this are transport events. Exploiting the instrument's advantages, the plume's trajectory during a prominent transport event could be reconstructed. Furthermore, the potential of retrieving information about the aerosol phase function from O4 slant columns along multiple almucantar scans of IMPACT is demonstrated, with promising results for future studies.
Strong Southward and Northward Currents Observed in the Inner Plasma Sheet
Authors: Yang Yanyan , Shen Chao , Ji Yong
Published: April 2019

Abstract. It is generally believed that field aligned currents (FACs) and the ring current (RC) are two dominant parts of the inner magnetosphere. However, using the Cluster spacecraft crossing of the pre-midnight inner plasma sheet in the latitude region between 10° N and 30° N, it is found that, during large storm events, in addition to FACs and the RC, there also exist strong southward and northward currents, which cannot be FACs, because the magnetic field in these regions is mainly along the XY plane. Detailed investigation shows that both magnetic field lines (MFLs) and currents in these regions highly fluctuate. When the curvature of MFLs changes direction in the XY plane, the current also alternatively switches between southward and northward. Further analysis of the current generation mechanism indicates that the most reasonable candidate for the origin of these southward and northward currents is the curvature drift of energetic particles.
Patterns of suspended particulate matter across the continental margin in the Canadian Beaufort Sea during summer
Authors: Ehn Jens K. , Reynolds Rick A. , Stramski Dariusz , Doxaran David , Lansard Bruno , Babin Marcel
Published: April 2019

Abstract. The particulate beam attenuation coefficient at 660 nm,
cp(660), was measured in conjunction with properties of suspended
particle assemblages in August 2009 within the Canadian Beaufort Sea
continental margin, a region heavily influenced by freshwater and sediment
discharge from the Mackenzie River, but also by sea ice melt. The mass
concentration of suspended particulate matter (SPM) ranged from 0.04 to 140 g m−3, its composition varied from mineral to organic dominated, and the
median particle diameter determined over the range 0.7–120 µm varied
from 0.78 to 9.45 µm, with the fraction of particles <1 µm in
surface waters reflecting the degree influenced by river water. Despite this
range in particle characteristics, a strong relationship between SPM and
cp(660) was found and used to determine SPM distributions across
the shelf based on measurements of cp(660) taken during summer
seasons of 2004, 2008, and 2009. SPM spatial patterns on the stratified shelf
reflected the vertically sheared two-layer estuarine circulation and SPM
sources (i.e., fluvial inputs, bottom resuspension, and biological
productivity). Along-shelf winds generated lateral Ekman flows, isopycnal
movements, and upwelling or downwelling at the shelf break. Cross-shelf
transects measured during three summers illustrate how sea ice meltwater
affects river plume extent, while the presence of meltwater on the shelf was
associated with enhanced near-bottom SPM during return flow of upwelled
Pacific-origin water. SPM decreased sharply past the shelf break with further
transport of particulate matter occurring near the bottom and in interleaving
nepheloid layers. These findings expand our knowledge of particle
distributions in the Beaufort Sea controlled by river discharge, sea ice, and
wind, each of which is sensitive to weather and climate variations.
N2O changes from the Last Glacial Maximum to the preindustrial – Part I: Quantitative reconstruction of terrestrial and marine emissions using N2O stable isotopes in ice cores
Authors: Fischer Hubertus , Schmitt Jochen , Bock Michael , Seth Barbara , Joos Fortunat , Spahni Renato , Lienert Sebastian , Battaglia Gianna , Stocker Benjamin D. , Schilt Adrian , Brook Edward J.
Published: April 2019

Abstract. Using high precision and centennial resolution ice core information on atmospheric nitrous oxide concentrations and its stable nitrogen and oxygen isotopic composition, we quantitatively reconstruct changes in the terrestrial and marine N2O emissions over the last 21,000 years. We show that N2O emissions from land and ocean increased largely in parallel by 1.7 ± 0.3 TgN yr−1 and 0.7 ± 0.3 TgN yr−1 over the deglaciation, respectively. However, during the abrupt Northern Hemisphere warmings at the onset of the Bølling/Allerød and the end of the Younger Dryas, terrestrial emissions respond more rapidly to the northward shift in the Intertropical Convergence Zone connected to the resumption of the Atlantic Meridional Overturning Circulation. 90 % of these large step increases were realized within maximum two centuries. In contrast, marine emissions start to slowly increase already many centuries before the rapid warmings, possibly connected to a re-equilibration of subsurface oxygen in response to previous changes. Marine emissions decreased, concomitantly with changes in atmospheric CO2 and δ13C(CO2), at the onset of the termination and remained minimal during the early phase of Heinrich Stadial 1. During the early Holocene a slow decline in marine N2O emission of 0.4 TgN yr−1 is reconstructed, suggesting an improvement of subsurface water ventilation in line with slowly increasing Atlantic overturning circulation. In the second half of the Holocene total emissions remain on a relatively constant level, however with significant millennial variability which is currently still difficult to attribute to marine or terrestrial sources. Our N2O emission records provide important quantitative benchmarks for ocean and terrestrial nitrogen cycle models to study the influence of climate on nitrogen turnover on time scales from several decades to glacial/interglacial changes.
The multi-scale structure of atmospheric energetic constraints on globally averaged precipitation
Authors: Nogueira Miguel
Published: April 2019

Abstract. This study presents a multi-scale analysis of cross-correlations based on
Haar fluctuations of globally averaged anomalies of precipitation (P),
precipitable water vapor (PWV), surface temperature (T), and atmospheric
radiative fluxes. The results revealed an emergent transition between weak
correlations at sub-yearly timescales (down to ∼5 days) to
strong correlations at timescales larger than about ∼1–2 years (up to
∼1 decade). At multiyear timescales, (i) Clausius–Clapeyron becomes the dominant control of PWV
(ρPWV,T≈0.9), (ii) surface temperature averaged over
global land and over global ocean (sea surface temperature, SST) become strongly correlated (ρTland,SST∼0.6); (iii) globally averaged precipitation
variability is dominated by energetic constraints, specifically the surface
downwelling longwave radiative flux (DLR) (ρP,DLR≈-0.8)
displayed stronger correlations than the direct response to T fluctuations,
and
(iv) cloud effects are negligible for the energetic constraints in (iii),
which are dominated by clear-sky DLR. At sub-yearly timescales, all
correlations underlying these four results decrease abruptly towards
negligible values. Such a transition has important implications for
understanding and quantifying the climate sensitivity of the global hydrological
cycle. The validity of the derived correlation structure is demonstrated by
reconstructing global precipitation time series at 2-year resolution,
relying on the emergent strong correlations (P vs. clear-sky DLR). Such a
simple linear sensitivity model was able to reproduce observed P anomaly
time series with similar accuracy to an (uncoupled) atmospheric model
(ERA-20CM) and two climate reanalysis (ERA-20C and 20CR). The linear
sensitivity breaks down at sub-yearly timescales, whereby the underlying
correlations become negligible. Finally, the relevance of the multi-scale
framework and its potential for stochastic downscaling applications are
demonstrated by deriving accurate monthly P probability density functions (PDFs)
from the reconstructed 2-year P time series based on scale-invariant
arguments alone. The derived monthly PDFs outperform the statistics
simulated by ERA-20C, 20CR, and ERA-20CM in reproducing observations.
Multi-model simulations of springtime dust storms in East Asia: Implications of an evaluation of four commonly used air quality models (CMAQv5.2.1, CAMxv6.50, CHIMEREv2017r4, and WRF-Chem v3.9.1)
Authors: Ma Siqi , Zhang Xuelei , Gao Chao , Tong Daniel Q. , Xiu Aijun , Wu Guangjian , Cao Xinyuan , Huang Ling , Zhao Hongmei , Zhang Shichun , Ibarra-Espinosa Sergio , Wang Xin , Li Xiaolan , Dan Mo
Published: April 2019

Abstract. Mineral dust particles play an important role in the Earth system, imposing a variety of effects on air quality, climate, human health, and economy. Accurate forecasts of dust events are highly desirable to provide early-warning and inform decision-making. East Asia is one of the largest dust sources in the world. This study applies and evaluates four widely used regional air quality models to simulate dust storms in East Asia. Three dust schemes in the Weather Research and Forecast with Chemistry (WRF-Chem) (version 3.9.1), two schemes in CHIMERE (version 2017r4) and CMAQ (version 5.2), and one scheme in CAMx (version 6.50), were applied to a dust event during May 4th~6th, 2015 in Northeastern China. Most of these models were able to capture this dust event, except CAMx which has no dust source map covering the study area, hence is excluded from subsequent analysis. Although these models reproduced the spatial pattern of the dust plume, there were large discrepancies between predicted and observed PM10 concentrations in each model. In general, CHIMERE had relatively better performance among all simulations with default configurations. After parameter tuning, WRF-Chem with the AFWA scheme using seasonal dust source map from Ginoux et al. (2012) showed the best performance, followed by WRF-Chem with UOC_Shao2011 scheme, CHIMERE, and CMAQ. This study suggested that the dust source maps should be carefully selected or replaced with a new one constructed with local data. Moreover, further study and measurement on sandblasting efficiency of different soil types and locations should be conducted to improve the accuracy of estimated vertical dust flux in air quality models.
Technical note: Stochastic simulation of streamflow time series using
phase randomization
Authors: Brunner Manuela I. , Bárdossy András , Furrer Reinhard
Published: April 2019

Abstract. Stochastically generated streamflow time series are widely used in water resource planning and management. Such series represent sets of plausible yet unobserved streamflow realizations which should reproduce the main characteristics of observed data. These characteristics include the distribution of daily streamflow values and their temporal correlation as expressed by short- and long-range dependence. Existing streamflow generation approaches have mainly focused on the time domain, even though simulation in the frequency domain provides good properties. These properties comprise the simulation of both short- and long-range dependence, as well as extension to multiple sites. Simulation in the frequency domain is based on the randomization of the phases of the Fourier transformation. We here combine phase randomization simulation with a flexible, four-parameter Kappa distribution, which allows for the extrapolation to yet unobserved low and high flows. The simulation approach consists of seven steps: 1) fitting the theoretical Kappa distribution, 2) normalization and deseasonalization, 3) Fourier transformation, 4) random phase generation, 5) inverse Fourier transformation, 6) back transformation, and 7) simulation. The simulation approach is applicable both to individual and multiple sites. It was applied to and validated on a set of four catchments in Switzerland. Our results show that the stochastic streamflow generator based on phase randomization produces realistic streamflow time series with respect to distributional properties and temporal correlation. However, cross-correlation among sites was in some cases found to be underestimated. The approach can be recommended as a flexible tool for various applications such as the dimensioning of reservoirs or the assessment of drought persistence.
Multicore structures and the splitting and merging of eddies in global oceans from satellite altimeter data
Authors: Cui Wei , Wang Wei , Zhang Jie , Yang Jungang
Published: April 2019

Abstract. This study investigated the statistics of eddy splitting and
merging in the global oceans based on 23 years of altimetry data. Multicore
structures were identified using an improved geometric closed-contour
algorithm of sea surface height. Splitting and merging events were discerned
from continuous time series maps of sea level anomalies. Multicore
structures represent an intermediate stage in the process of eddy evolution,
similar to the generation of multiple nuclei in a cell as a preparatory
phase for cell division. Generally, splitting or merging events can
substantially change (by a factor of 2 or more) the eddy scale, amplitude, and
eddy kinetic energy. Specifically, merging (splitting) generally causes an
increase (decrease) of eddy properties. Multicore eddies were found to tend
to split into two eddies with different intensities. Similarly, eddy merging
is not an interaction of two equal-intensity eddies, and it tends to
manifest as a strong eddy merging with a weaker one. A hybrid tracking
strategy based on the eddy overlap ratio, considering both multicore and
single-core eddies, was used to confirm splitting and merging events
globally. The census revealed that eddy splitting and merging do not always
occur most frequently in eddy-rich regions; e.g., their frequencies of
occurrence in the Antarctic Circumpolar Current and western boundary
currents were found to be greater than in midlatitude regions
(20–35∘) to the north and south. Eddy splitting and merging
are caused primarily by an unstable configuration of multicore structures
due to obvious current– or eddy–topography interaction, strong current
variation, and eddy–mean flow interaction.
A key factor initiating surface ablation of Arctic sea ice: earlier and increasing liquid precipitation
Authors: Dou Tingfeng , Xiao Cunde , Liu Jiping , Han Wei , Du Zhiheng , Mahoney Andrew R. , Jones Joshua , Eicken Hajo
Published: April 2019

Abstract. Snow plays an important role in the Arctic climate system,
modulating heat transfer in terrestrial and marine environments and
controlling feedbacks. Changes in snow depth over Arctic sea ice,
particularly in spring, have a strong impact on the surface energy budget,
influencing ocean heat loss, ice growth and surface ponding. Snow conditions
are sensitive to the phase (solid or liquid) of deposited precipitation.
However, variability and potential trends of rain-on-snow events over Arctic
sea ice and their role in sea-ice losses are poorly understood. Time series
of surface observations at Utqiaġvik, Alaska, reveal rapid reduction in
snow depth linked to late-spring rain-on-snow events. Liquid precipitation
is key in preconditioning and triggering snow ablation through reduction in
surface albedo as well as latent heat release determined by rainfall amount,
supported by field observations beginning in 2000 and model results.
Rainfall was found to accelerate warming and ripening of the snowpack, with
even small amounts (such as 0.3 mm recorded on 24 May 2017)
triggering the transition from the warming phase into the ripening phase.
Subsequently, direct heat input drives snowmelt, with water content of the
snowpack increasing until meltwater output occurs, with an associated rapid
decrease in snow depth. Rainfall during the ripening phase can further raise
water content in the snow layer, prompting onset of the meltwater output
phase in the snowpack. First spring rainfall in Utqiaġvik has been
observed to shift to earlier dates since the 1970s, in particular after the
mid-1990s. Early melt season rainfall and its fraction of total annual
precipitation also exhibit an increasing trend. These changes of
precipitation over sea ice may have profound impacts on ice melt through
feedbacks involving earlier onset of surface melt.