bluuebunny/crossref_metadata_2025 huggingface dataset:
AlistagTM, a new coating agent for aging cheese and hams
Authors: Principato Mario A. , Cascone Salvatore , Cenci Goga Beniamino T. , Moretta Iolanda , Principato Simona
Published: July 2018

Aging rooms of dry-cured ham and cheese are subject to the development of mold and arthropods, above all mites, which cause the erosion of the external part of these food products, reducing their surface to dust and determining their progressive degradation. This work is meant to give the results of an experiment carried out to test the level of protection supplied by AlistagTM, a coating agent based on Gluconodeltalactone, on a typical Sicilian cheese cosacavaddu ibleo. AlistagTM was applied by nebulization and by immersion. The two parameters took in consideration to evaluate their efficacy were the presence/absence of cracks and the level of dustiness on the surface of the cheese. AlistagTM turned out to be very efficient in protecting cheese both from the development of dust and from cracks; between the two kinds of application tested, immersion resulted to be the best one, for the protecting action lasts longer.
Kebab: can the traditional cooking process sanitize a natural contamination by Listeria monocytogenes?
Authors: Bonilauri Paolo , Leonelli Roberto , Ferrarini Gabriele , Carobbi Diego , Ossiprandi Maria Cristina , Dottori Michele , Cuccurese Antonio
Published: July 2018

Over the last few years a considerable spread of ethnic foods was observed in Italy. Among them is the Döner kebab. During 2014-2015, in order to evaluate the effectiveness of traditional cooking process, raw product (defrosted), sliced cooked portions cut through electric knife and assembled sandwich were officially sampled in kebab houses and in a local industrial kebab producer in Reggio Emilia (a province in Italy). Microbiological researches for safety and hygienic microbiological indicators were carried out (research of Salmonella, Listeria monocytogenes, Campylobacter and Shiga toxin-producing Escherichia coli; enumeration mesophilic aerobic bacteria, lactic acid bacteria, sulfite-reducing bacteria growing under anaerobic conditions, yeasts and molds). Between the raw and the cooked product an average of 3 log reduction in mesophilic aerobic bacteria counts was observed. In two out of three kebab houses sampled, which were supplied by the same local industrial producer, the presence of L. monocytogenes was detected. During the official inspection carried out at the production plant a contamination of L. monocytogenes was assessed in both ambient and instruments. Furthermore, 3 lots of products were analyzed and all were found to be contaminated by L. monocytogenes (always above 100 CFU/g). In order to verify the capability of the traditional cooking process to reduce the risk of contamination at an acceptable level, a batch of naturally contaminated kebab (4.5 log CFU/g) was cooked and sliced simulating a day work activity in a kebab shop. The product was then sampled during preparation and enumeration of L. monocytogenes was obtained. After an hour of cooking, the residual contamination was 1.8 log CFU/g, after two hours and a half L. monocytogenes was no longer detectable in the product, but half an hour later it was again detectable in 25g. At the end of the experiment, the contamination grown up to the same level enumerated after an hour of cooking (1.8 log CFU/g). Considering the microbiological results, traditional cooking obtained a rate of -2.40 log CFU/gh-1, a D=26 min that corresponds to a temperature of maximum 60°C (z=6). In conclusion, our experiment demonstrates the traditional kebab cooking process could not always guarantee a complete product decontamination.
Ankle edema after administration of selective serotonin reuptake inhibitors
Authors: Kontoangelos Konstantinos , Ecomomou Marina , Papageorgiou Charalambos
Published: July 2018

Clinical manifestations of drug-induced skin reactions include a wide range of symptoms, from mild drug-induced exanthemas to dangerous and life-threatening generalized systematic reactions. Druginduced skin reactions to psychotropic medication are usually associated with antiepileptic drugs. However, a significant role can be assigned to selective serotonin reuptake inhibitors. We report a case of a female patient, who after approximately one month therapy with escitalopram developed a bilateral ankle edema, which resolved completely within the first week following its discontinuation. Although serious complications are rare, clinicians should be aware of severe skin complications in patients treated with antidepressants, which necessitate careful clinical monitoring and management. Individualization of pharmacotherapy is crucial, together with regular evaluation of safety and tolerance of the treatment.
Addiction and religiosity in facing suicide: A qualitative study on meaning of life and death among homeless people
Authors: Testoni Ines , Russotto Salvatore , Zamperini Adriano , De Leo Diego
Published: July 2018

This qualitative research explores the relationship between religiosity, suicide thoughts and drug abuse among 55 homeless people, interviewed with interpretative phenomenological analysis. Analyzing the thematic structure of the participants’ narrations, important main themes appeared in order to avoid suicide, among which family, the certainty of finding a solution and the will to live. However, the suicide ideation inheres in about 30% of participants, almost all believers, addicted and/or alcoholics. Results suggest that religiosity and meaning of death neither prevent from substances abuse and alcoholism, nor is a protective factor against suicide ideation. Meanings of life are the most important reasons for living, and when they are definitively considered unworkable, alcohol and drug help to endure life in the street. A specific model is discussed.
The Turkish adaptation and psychometric properties of the Geriatric Anxiety Scale
Authors: Sanal Karahan Faika , Hamarta Erdal , Karahan Ali Yavuz
Published: July 2018

The purpose of the present study is to translate and adapt the Geriatric Anxiety Scale (GAS), a 30-item self-report measure of anxiety among older adults, into Turkish and examine its basic psychometric properties. We tested the translated GAS in a sample of community-dwelling older adults in Konya, Turkey (N=100; Mage=71.4 years, SD=6.5; range=65-88) without a history of mental disorder and sufficient cognitive abilities. To assess the convergent validity, Turkish versions of the Beck Anxiety Inventory (BAI) and Geriatric Depression Scale (GDS) were administered. The mean GAS total score was 13.33 (SD=11.86). Due to low item-total correlations (<0.30), two items (items 2 and 3) were removed from the Turkish version of the GAS. The internal reliability (Cronbach’s alpha) was excellent for the total score (0.91) and acceptable for the subscales (somatic = 0.71; cognitive = 0.85; affective = 0.84). Regarding the convergent validity, the GAS total score was significantly and positively correlated with the total scores of the BAI (r=0.87, P<0.05) and GDS (r=0.57, P<0.05), with large effect sizes. Implications: The newly translated Turkish version of the GAS has promising utility in an older adult Turkish sample. Future studies of this measure are warranted.
Towards the preferred stimulus parameters for distortion product otoacoustic emissions in adults: A preliminary study
Authors: Petersen Lucretia , Wilson Wayne J. , Kathard Harsha
Published: July 2018

Background: Although distortion product otoacoustic emissions (DPOAEs) are useful in evaluating cochlear outer hair cell function, determining the optimal stimulus parameters could result in a more reliable, sensitive and specific diagnostic tool across the range of DPOAE applications. Objectives: To identify which stimulus parameters warrant further investigation for eliciting the largest and most reliable DPOAEs in adult humans. Method: A single group, repeated measures design involving a convenience sample of 20 normal-hearing participants between 19 and 24 years of age. Results: Descriptive statistics and mixed model analyses suggested L1/L2 intensity levels of 65/65 dB sound pressure level (SPL) and 65/55 dB SPL, and f2/f1 ratios of 1.18, 1.20 and 1.22 elicited larger and more reliable DPOAEs in both ears. Conclusion: Further investigation of the 65/65 dB SPL and 65/55 dB SPL intensity levels and the 1.18, 1.20 and 1.22 f2/f1 ratios is warranted to determine the stimulus parameters for eliciting the largest and most reliable DPOAEs in adult humans across the range of DPOAE applications.
Language and culture in speech-language and hearing professions in South Africa: The dangers of a single story
Authors: Khoza-Shangase Katijah , Mophosho Munyane
Published: July 2018

Background: Speech-language and hearing (SLH) professions in South Africa are facing significant challenges in the provision of clinical services to patients with communication disorders from a context that is culturally and linguistically diverse because of historic exclusions of black and African language speaking candidates in higher education training programmes. Over 20 years post the democratic dispensation, minimal changes have been noted in terms of the training, research as well as clinical service provision in these professions, although the demographic profile of students is seen to be transforming gradually. Objectives: We offer this viewpoint publication as a challenge to the professions to interrogate their academic and clinical orientation in respect of African contextual relevance and responsiveness. Method: We do this by identifying gaps within the higher education context, highlighting the influencing factors to the provision of linguistically and culturally appropriate SLH training and clinical services in South Africa, while asking questions about what SLH students and practitioners need to carefully consider. Results: We make recommendations about what needs to happen within the SLH professions in South Africa in order to stay safe from the dangers of a single story. Conclusion: We invite debate in order to allow for constructive engagement with this complex issue within the South African SLH professions.
Approximation of sets of finite fractional perimeter by smooth sets and comparison of local and global s-minimal surfaces
Authors: Lombardini Luca
Published: July 2018

This article is divided into two parts. In the first part we show that a set

E

has locally finite

s

-perimeter if and only if it can be approximated in an appropriate sense by smooth open sets. In the second part we prove some elementary properties of local and global

s

-minimal sets, such as existence and compactness. We also compare the two notions of minimizer (i.e., local and global), showing that in bounded open sets with Lipschitz boundary they coincide. Conversely, in general this is not true in unbounded open sets, where a global s-minimal set may fail to exist (we provide an example in the case of a cylinder

\Omega \times \mathbb R

).
A multiple scale pattern formation cascade in reaction-diffusion systems of activator-inhibitor type
Authors: Henry Marie , Hilhorst Danielle , Muratov Cyrill B.
Published: July 2018

A family of singular limits of reaction-diffusion systems of activator-inhibitor type in which stable stationary sharp-interface patterns may form is investigated. For concreteness, the analysis is performed for the FitzHugh-Nagumo model on a suitably rescaled bounded domain in

\mathbb R^N

, with

N \geq 2

. It is shown that when the system is sufficiently close to the limit the dynamics starting from the appropriate smooth initial data breaks down into five distinct stages on well-separated time scales, each of which can be approximated by a suitable reduced problem. The analysis allows to follow fully the progressive refinement of spatio-temporal patterns forming in the systems under consideration and provides a framework for understanding the pattern formation scenarios in a large class of physical, chemical, and biological systems modeled by the considered class of reaction-diffusion equations.
Arithmetic harmonic analysis for smooth quartic Weyl sums: three additive equations
Authors: Brüdern Jörg , Wooley Trevor D.
Published: July 2018

We establish the non-singular Hasse principle for systems of three diagonal quartic equations in 32 or more variables, subject to a certain rank condition. Our methods employ the arithmetic harmonic analysis of smooth quartic Weyl sums and also a new estimate for their tenth moment.
O uso de metodologias ativas na promoção da autonomia de alunos de Engenharia Civil
Authors: Covre Bastos Nolasco Patrícia
Published: July 2018

Thisarticlebringsareflectionbasedonliteraturearoundtherelationshipbetweenteachingandlearningprocessbasedonclassroomexperiencesandusingactivemethodologiestoallowanincreaseonthecognitiveandaffectiveaspectsonauni-versitycourseofCivilEngineering.Theobjectiveistoidentifyandstablishtherelationshipbetweenstudentsandteachersaswellasthedevelopmentofteachingmethodscenteredonthestudent,usingactivemethodologiesandsearchingtomeettheir professional needs and expectations on a globalized context. The article proposes the review methods and proceduresthat can result in future experiments in order to increase and fundament the debate around the improvement of teachingquality.Thearticleexemplifieslearningmethodsanditsessentialcharacteristics,focusingonProblemBasedLearningduetoitspotentialtoincreasetheparticipationanddecisionleveloftheteacheronthestudent’slearningprocess
The efficiency of secondary organic aerosol particles acting as ice-nucleating particles under mixed-phase cloud conditions
Authors: Frey Wiebke , Hu Dawei , Dorsey James , Alfarra M. Rami , Pajunoja Aki , Virtanen Annele , Connolly Paul , McFiggans Gordon
Published: July 2018

Abstract. Secondary organic aerosol (SOA) particles have been found to be efficient
ice-nucleating particles under the cold conditions of (tropical)
upper-tropospheric cirrus clouds. Whether they also are efficient at
initiating freezing under slightly warmer conditions as found in mixed-phase
clouds remains undetermined. Here, we study the ice-nucleating ability of
photochemically produced SOA particles with the combination of the Manchester
Aerosol Chamber and Manchester Ice Cloud Chamber. Three SOA systems were
tested resembling biogenic and anthropogenic particles as well as particles
of different phase state. These are namely α-pinene, heptadecane, and
1,3,5-trimethylbenzene. After the aerosol particles were formed, they were
transferred into the cloud chamber, where subsequent quasi-adiabatic cloud
activation experiments were performed. Additionally, the ice-forming
abilities of ammonium sulfate and kaolinite were investigated as a reference
to test the experimental setup. Clouds were formed in the temperature range of −20 to −28.6 ∘C.
Only the reference experiment using dust particles showed evidence of ice
nucleation. No ice particles were observed in any other experiment. Thus, we
conclude that SOA particles produced under the conditions of the reported
experiments are not efficient ice-nucleating particles starting at liquid
saturation under mixed-phase cloud conditions.
EUBREWNET RBCC-E Huelva 2015 Ozone Brewer Intercomparison
Authors: Redondas Alberto , Carreño Virgilio , León-Luis Sergio F. , Hernández-Cruz Bentorey , López-Solano Javier , Rodriguez-Franco Juan J. , Vilaplana José M. , Gröbner Julian , Rimmer John , Bais Alkiviadis F. , Savastiouk Vladimir , Moreta Juan R. , Boulkelia Lamine , Jepsen Nis , Wilson Keith M. , Shirotov Vadim , Karppinen Tomi
Published: July 2018

Abstract. From 25 May to 5 June 2015, the 10th regional intercomparison campaign of the Regional Brewer Calibration Center – Europe (RBCC-E) was held at El Arenosillo atmospheric sounding station of the Instituto Nacional de Técnica Aeroespacial (INTA). This campaign was jointly conducted by COST Action ES1207 EUBREWNET and the Area of Instrumentation and Atmospheric Research of INTA. A total of 21 Brewers, 11 single- and 10 double-monochromator instruments from 11 countries participated and were calibrated for total column ozone (TOC) and solar UV irradiance. In this 2015 campaign we have introduced a formal approach to the characterisation of the internal instrumental stray light, the filter non-linearity and the algorithm for correcting for its effects on the TOC calculations. This work shows a general overview of the ozone comparison and the evaluation of the correction of the spectral stray light effect for the single-monochromator Brewer spectrophotometer, derived from the comparison with a reference double-monochromator Brewer instrument. At the beginning of the campaign, 16 out of the 21 participating Brewer instruments agreed within better than ±1 %, and 10 instruments agreed within better than ±0.5 % considering data with ozone slant column between 100 and 900 DU, which does not require instrumental stray light correction.
Characteristics of marine shipping emissions at berth: profiles for particulate matter and volatile organic compounds
Authors: Xiao Qian , Li Mei , Liu Huan , Fu Mingliang , Deng Fanyuan , Lv Zhaofeng , Man Hanyang , Jin Xinxin , Liu Shuai , He Kebin
Published: July 2018

Abstract. Emissions from ships at berth play an important role regarding the exposure
of high density human populations to atmospheric pollutants in port areas;
however, these emissions are not well understood. In this study, volatile
organic compounds (VOCs) and particle emissions from 20 container ships at
berth were sampled and analyzed during the “fuel switch” period at Jingtang
Port in Hebei Province, China. VOCs and particles were analyzed using a gas
chromatography-mass spectrometer (GC-MS) and a single particle aerosol mass
spectrometer (SPAMS), respectively. VOC analysis showed that alkanes and
aromatics, especially benzene, toluene and heavier compounds e.g.,
n-heptane, n-octane and n-nonane, dominated the total identified
species. Secondary organic aerosol (SOA) yields and ozone (O3)
forming potential were
0.017 ± 0.007 g SOA g−1 VOCs and
2.63 ± 0.37 g O3 g−1 VOCs, respectively. Both positive and
negative ion mass spectra from individual ships were derived and the
intensity of specific ions were quantified. Results showed that elemental
carbon (35.74 %), elemental carbon–organic carbon mixtures (33.95 %)
and Na-rich particles (21.12 %) were major classes, comprising 90.7 %
of the particles observed. Particles from ship auxiliary engines were in the
0.2 to 2.5 µm size range, with a peak occurring at around
0.4 µm. The issue of using vanadium (V) as tracer element was
examined, and it was found that V was not a proper tracer of ship emissions
when using low sulfur content diesel oil. The average percentage of sulfate
particles observed in shipping emissions before and after switching to marine
diesel oil remained unchanged at 24 %. Under certain wind conditions,
when berths were upwind of emission sources, the ratios before and after
1 January were 35 and 27 % respectively. The impact of atmospheric
stability was discussed based on PM2.5 and primary pollutant (carbon
monoxide) concentration. With a background of frequent haze episodes and
complex mechanisms of particulate accumulation and secondary formation, the
impact of atmospheric stability is believed to have been weak on the sulfate
contribution from shipping emissions. The results from this study provide
robust support for port area air quality assessment and source apportionment.
Multi-static spatial and angular studies of polar mesospheric summer echoes combining MAARSY and KAIRA
Authors: Chau Jorge L. , McKay Derek , Vierinen Juha P. , La Hoz Cesar , Ulich Thomas , Lehtinen Markku , Latteck Ralph
Published: July 2018

Abstract. Polar mesospheric summer echoes (PMSEs) have been long associated with
noctilucent clouds (NLCs). For large ice particles sizes and relatively high
ice densities, PMSEs at 3 m Bragg wavelengths are known to be good tracers of
the atmospheric wind dynamics and to be highly correlated with NLC
occurrence. Combining the Middle Atmosphere ALOMAR Radar System (MAARSY) and
the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA), i.e.,
monostatic and bistatic observations, we show for the first time direct
evidence of limited-volume PMSE structures drifting more than 90 km almost
unchanged. These structures are shown to have horizontal widths of
5–15 km and are separated by 20–60 km, consistent with structures due to atmospheric
waves previously observed in NLCs from the ground and from space. Given the
lower sensitivity of KAIRA, the observed features are attributed to echoes
from regions with high Schmidt numbers that provide a large radar
cross section. The bistatic geometry allows us to determine an upper value
for the angular sensitivity of PMSEs at meter scales. We find no
evidence for strong aspect sensitivity for PMSEs, which is consistent
with recent observations using radar imaging approaches. Our results indicate
that multi-static all-sky interferometric radar observations of PMSEs could be
a powerful tool for studying mesospheric wind fields within large geographic
areas.
Sensitivity of biogenic volatile organic compound emissions to leaf area index and land cover in Beijing
Authors: Wang Hui , Wu Qizhong , Liu Hongjun , Wang Yuanlin , Cheng Huaqiong , Wang Rongrong , Wang Lanning , Xiao Han , Yang Xiaochun
Published: July 2018

Abstract. The Beijing area has suffered from severe air pollution in
recent years, including ozone pollution in the summer. In addition to the
anthropogenic emissions inventory, understanding local ozone pollution
requires a reliable biogenic volatile organic compound (BVOC) emission
inventory. Forest coverage rose from 20.6 to 35.8 % from 1998 to 2013 in
Beijing according to the National Forest Resource Survey (NFRS), and accurate
representations of land cover for recent years is crucial for estimating BVOC
emissions and their impacts on air quality. In this study, we established a
high-resolution BVOC emission inventory in Beijing using the Model of
Emissions of Gases and Aerosols from Nature (MEGAN) v2.1 with three
independent leaf area index (LAI) products and three independent land cover
products. Various combinations of the Global LAnd Surface Satellite (GLASS),
Moderate-Resolution Imaging Spectroradiometer (MODIS) MCD15, and GEOland
(GEO) v2 LAI datasets and the Finer Resolution Observation and Monitoring of
Global Land Cover (FROM-GLC), MODIS MCD12Q1 plant functional type (PFT)
products, and Climate Change Initiative Land Cover (CCI LC) products are used
in five model sensitivity experiments (E1–E5), and the experiment using the
FROM-GLC with the highest spatial resolution of 30 m and GLASS LAI products was
treated as the baseline. These sensitivity calculations were driven by
hourly, 3 km meteorological fields from the Weather Research and Forecasting
(WRF) model. The following results were obtained: (1) according to the
baseline estimate, the total amount of BVOC emissions is 75.9 Gg for the
Beijing area, and isoprene, monoterpenes, sesquiterpenes and other VOCs
account for 37.6, 14.6, 1.8 and 46 % of the total, respectively.
Approximately three-quarters of BVOC emissions occur in the summer.
(2) According to the sensitivity experiments, the LAI input does not
significantly affect the BVOC emissions. Using MODIS MCD15Q1 and GEO v2 LAI
led to slight declines of 2.6 and 1.4 %, respectively, of BVOC emissions
in the same area. (3) The spatial distribution of PFTs from different inputs
strongly influenced the spatial distribution of BVOC emissions. Furthermore,
the cross-walking table for converting land cover classes to PFTs also has a
strong impact on BVOC emissions; the sensitivity experiments showed that the
estimate of BVOC emissions by CCI LC ranged from 42.1 to 70.2 Gg depending
on the cross-walking table used.
An apportionment method for the oxidative potential of atmospheric particulate matter sources: application to a one-year study in Chamonix, France
Authors: Weber Samuël , Uzu Gaëlle , Calas Aude , Chevrier Florie , Besombes Jean-Luc , Charron Aurélie , Salameh Dalia , Ježek Irena , Močnik Griša , Jaffrezo Jean-Luc
Published: July 2018

Abstract. Inhaled aerosolized particulate matter (PM) induces cellular oxidative stress in
vivo, leading to adverse health outcomes. The oxidative potential (OP) of PM
appears to be a more relevant proxy of the health impact of the aerosol rather
than the total mass concentration. However, the relative contributions of the
aerosol sources to the OP are still poorly known. In order to better quantify
the impact of different PM sources, we sampled aerosols in a French city for one
year (2014, 115 samples). A coupled analysis with detailed chemical
speciation (more than 100 species, including organic and carbonaceous compounds,
ions, metals and aethalometer measurements) and two OP assays (ascorbic acid, AA, and dithiothreitiol, DTT) in a simulated lung fluid (SLF) were performed
in these samples. We present in this study a statistical framework using a
coupled approach with positive matrix factorization (PMF) and multiple linear
regression to attribute a redox-activity to PM sources. Our results highlight
the importance of the biomass burning and vehicular sources to explain the
observed OP for both assays. In general, we see a different contribution of the
sources when considering the OP AA, OP DTT or the mass of the
PM10. Moreover, significant differences are observed between
the DTT and AA tests which emphasized chemical specificities of the two tests
and the need of a standardized approach for the future studies on
epidemiology or toxicology of the PM.
Satellite evidence of substantial rain-induced soil emissions of ammonia across the Sahel
Authors: Hickman Jonathan E. , Dammers Enrico , Galy-Lacaux Corinne , van der Werf Guido R.
Published: July 2018

Abstract. Atmospheric ammonia (NH3) is a precursor to fine particulate matter formation and contributes to nitrogen deposition, with potential implications for the health of humans and ecosystems. Agricultural soils and animal excreta are the primary source of atmospheric NH3, but natural soils can also be an important emittor. In regions with distinct dry and wet seasons such as the Sahel, the start of the rainy season triggers a pulse of biogeochemical activity in surface soils known as the Birch effect, which is often accompanied by emissions of microbially-produced gases such as carbon dioxide and nitric oxide. Field and lab studies have sometimes, but not always, observed pulses of NH3 after the wetting of dry soils; however, the potential regional importance of these emissions remains poorly constrained. Here we use satellite retrievals of atmospheric NH3 using the Infrared Atmospheric Sounding Interferometer (IASI) regridded at 0.25° resolution, in combination with satellite-based observations of precipitation, surface soil moisture, and nitric dioxide concentrations, to present evidence of substantial precipitation-induced pulses of NH3 across the Sahel at the onset of the rainy season in 2008. The highest concentrations of NH3 occur in pulses during March and April, when biomass burning emissions estimated for the region by the Global Fire Emissions Database database are low. For the region of the Sahel spanning 10° to 16° N and 0° to 30° E, changes in NH3 concentrations are weakly but significantly correlated with changes in soil moisture during the period from mid-March through April, when the peak NH3 concentrations occur (r = 0.28, p = 0.02). The correlation is also present when evaluated on an individual pixel-basis during April (r = 0.16, p
Chlorine Nitrate in the Atmosphere
Authors: von Clarmann Thomas , Johansson Sören
Published: July 2018

Abstract. This review article compiles the characteristics of the gas chlorine nitrate and discusses its role in atmospheric chemistry. Chlorine nitrate is a reservoir of both stratospheric chlorine and nitrogen. It is formed by a termolecular reaction of ClO and NO2. Sink processes include gas-phase chemistry, photo-dissociation, and heterogeneous chemistry on aerosols. The latter sink is particularly important in the context of polar spring stratospheric chlorine activation. ClONO2 has vibrational-rotational bands in the infrared, notably at 779 cm−1, 809 cm−1, 1293 cm−1, and 1735 cm−1, which are used for remote sensing of ClONO2 in the atmosphere. Mid-infrared emission and absorption spectroscopy have long been the only concepts for atmospheric ClONO2 measurements. More recently, fluorescence and mass spectroscopic in situ techniques have been developed. Global ClONO2 distributions have a maximum at polar winter latitudes at about 20–30 km altitude, where mixing ratios can exceed 2 ppbv. The annual cycle is most pronounced in the polar stratosphere, where ClONO2 concentrations are an indicator of chlorine activation and de-activation.
Large contrast in the vertical distribution of aerosol optical properties and radiative effects across the Indo-Gangetic Plain during SWAAMI-RAWEX campaign
Authors: Vaishya Aditya , Babu Surendran Nair Suresh , Jayachandran Venugopalan , Gogoi Mukunda M. , Lakshmi Naduparambil Bharathan , Moorthy Krishnaswamy Krishna , Satheesh Sreedharan Krishnakumari
Published: July 2018

Abstract. Measurements of the vertical profiles of the optical properties (namely the extinction / scattering and absorption coefficients; respectively σext / σscat / σabs) of aerosols have been made across the Indo-Gangetic Plain (IGP) using an instrumented aircraft operated from three base stations (Jodhpur (JDR) representing the semiarid western IGP; Varanasi (VNS) the central IGP characterized by significant anthropogenic activities; and the industrialised coastal location in the eastern end of the IGP (Bhubaneswar, BBR)), just prior to the onset of the Indian Summer monsoon. The vertical profiles depicted region-specific absorption characteristics, while the scattering characteristics remained fairly uniform across the region, leading to a west-east gradient in the vertical structure of single scattering albedo (SSA). Integrated from near ground to 3 km, the highest absorption coefficient and hence the lowest SSA occurred in the central IGP (Varanasi). Size distribution, inferred from the spectral variation of the scattering coefficient, showed a gradual shift from coarse particle dominance in the western IGP to strong accumulation dominance in the eastern coast with the central IGP coming in-between, arising from a change in the aerosol type from predominantly natural (dust and sea-salt) type in the western IGP to highly anthropogenic type (industrial emissions, fossil fuel and biomass combustion) in the eastern IGP; the central IGP exhibiting a mixture of both. Aerosol induced short-wave radiative forcing, estimated using altitude resolved SSA information, revealed significant atmospheric warming in the central IGP while a top-of-atmosphere cooling is seen, in general, in the IGP. Atmospheric heating rate profiles, estimated using altitude resolved SSA and column average SSA, revealed considerable underestimation in the latter case, emphasising the importance and necessity of having altitude resolved SSA information as against a single value for the entire column.
Can interplanetary magnetic field reach the Venus surface?
Authors: Narita Yasuhito , Motschmann Uwe
Published: July 2018

Abstract. The question is addressed if there is a possibility of interplanetary magnetic field reaching the Venus surface by magnetic diffusion across the ionosphere. We present a model calculation and estimate the magnetic diffusion time at Venus, and find out that the typical diffusion time scale is in a range between 11 and 40 h, depending on the solar activity and the ionospheric magnetic field condition. Magnetic field can thus permeate Venus surface and even Venus interior when the solar wind is stationary (i.e., no magnetic field reversal) on the time scale of half-a-day to several days.
Multiscale estimation of the field-aligned current density
Authors: Bunescu Costel , Vogt Joachim , Blagau Adrian , Marghitu Octav
Published: July 2018

Abstract. Field-aligned currents (FACs) in the magnetosphere-ionosphere (M-I) system exhibit a range of spatial and temporal scales that are linked to key dynamic coupling processes. To disentangle the scale dependence in magnetic field signatures of auroral FACs and to characterize their geometry and orientation, Bunescu et al. (2015) introduced the multi-scale FAC analyzer framework based on minimum variance analysis (MVA) of magnetic time series segments. In the present report this approach is carried further to include in the analysis framework a FAC density scalogram, i.e., a multiscale representation of the FAC density time series. The new technique is validated and illustrated using synthetic data consisting of overlapping sheets of FACs at different scales. The method is applied to Swarm data showing both large-scale and quiet aurora as well as mesoscale FAC structures observed during more disturbed conditions. We show both planar and non-planar FAC structures as well as uniform and non-uniform FAC density structures. For both, synthetic and Swarm data, the multiscale analysis is applied by two scale sampling schemes, namely the linear, and the logarithmic scanning of the FACs scale domain. The scale integrated FAC density is computed by both small-scale and large-scale weighting. The integrated multiscale FAC density is compared with the input FAC density for the synthetic data, whereas for the Swarm data we cross-check the results with well established single- and dual-spacecraft techniques. The entire multiscale information provides a new visualization tool for the complex FAC signatures, that complement other FAC analysis tools.
On the variability of the semidiurnal solar and lunar tides of the equatorial electrojet during sudden stratospheric warmings
Authors: Siddiqui Tarique A. , Maute Astrid , Pedatella Nick , Yamazaki Yosuke , Lühr Hermann , Stolle Claudia
Published: July 2018

Abstract. The variabilities of the semidiurnal solar and lunar tide of the equatorial electrojet (EEJ) are investigated during the 2003, 2006, 2009 and 2013 major sudden stratospheric warming (SSW) events in this study. For this purpose, the ground-magnetometer recordings at the equatorial observatories in Huancayo and Fuquene are utilized. Results show a major enhancement in the amplitude of the EEJ semidiurnal lunar tide in each of the four warming events. The EEJ semidiurnal solar tidal amplitude shows an amplification prior to the onset of warmings, a reduction during the deceleration of the zonal mean zonal wind at 60° N and 10 hPa and a second enhancement a few days after the peak reversal of the zonal mean zonal wind during all the four SSWs. Results also reveal that the amplitude of the EEJ semidiurnal lunar tide becomes comparable or even greater than the amplitude of the EEJ semidiurnal solar tide during all these warming events. The present study also compares the EEJ semidiurnal solar and lunar tidal changes with numerical simulations of the variability of the migrating semidiurnal solar (SW2) and lunar (M2) tide in neutral temperature at ~ 120 km altitude. A better agreement between the enhancements of the EEJ semidiurnal lunar tide and the M2 tide in neutral temperature is observed in comparison with the enhancements of the EEJ semidiurnal solar tide and the SW2 tide in neutral temperature.
Plant-microbe Symbioses Reveal Underestimation of Modeled Climate Impacts
Authors: Shi Mingjie , Fisher Joshua B. , Phillips Richard P. , Brzostek Edward R.
Published: July 2018

Abstract. The extent to which terrestrial ecosystems slow climate change by sequestering carbon hinges in part on nutrient limitation. We used a coupled carbon–climate model that accounts for the carbon cost to plants of supporting nitrogen-acquiring microbial symbionts to explore how nitrogen limitation affects global climate. The carbon costs of supporting symbiotic nitrogen uptake reduced net primary production, with the largest absolute effects occurring at low-latitudes and the largest relative changes occurring at high-latitudes. The largest impact occurred in high-latitude ecosystems, where such costs were estimated to increase temperature by 1.0 °C and precipitation by 9 mm yr−1. Globally, our model predicted that nitrogen limitation enhances temperature and decreases precipitation; as such, our results suggest that carbon expenditures to support nitrogen-acquiring microbial symbionts have critical consequences for Earth’s climate, and that carbon–climate models that omit these processes will over-predict the land carbon sink and under-predict climate change.
Eemian Greenland Surface Mass Balance strongly sensitive to SMB model choice
Authors: Plach Andreas , Nisancioglu Kerim H. , Le clec’h Sébastien , Born Andreas , Langebroek Petra M. , Guo Chuncheng , Imhof Michael , Stocker Thomas F.
Published: July 2018

Abstract. Understanding the behavior of the Greenland ice sheet in a warmer climate, and particularly its surface mass balance (SMB), is important for assessing Greenland’s potential contribution to future sea level rise. The Eemian interglacial, the most recent warmer-than-present period in Earth’s history approximately 125 000 years ago, provides an analogue for a warm summer climate over Greenland. The Eemian is characterized by a positive Northern Hemisphere summer insolation anomaly, which introduces uncertainties in Eemian SMB when using positive degree day estimates. In this study, we use Eemian global and regional climate simulations in combination with three types of SMB models – a simple positive degree day, an intermediate complexity, and a full surface energy balance model – to evaluate the importance of regional climate and model complexity for estimates of Greenland SMB. We find that all SMB models perform well under the relatively cool pre-industrial and late Eemian. For the relatively warm early Eemian, the differences between SMB models are large which is associated with the representation of insolation in the respective models. For all simulated time slices there is a systematic difference between globally and regionally forced SMB models, due to the different representation of the regional climate over Greenland. We conclude that both the resolution of the simulated climate as well as the method used to estimate the SMB, are important for an accurate simulation of Greenland’s SMB. Whether model resolution or SMB method is most important depends on the climate state and in particular the prevailing insolation pattern. We suggest that future Eemian climate model inter-comparison studies are combined with different SMB models to quantify Eemian SMB uncertainty estimates.
Building a Raspberry Pi School Magnetometer Network in the UK
Authors: Beggan Ciarán D. , Marple Steve R.
Published: July 2018

Abstract. As computing and geophysical sensor components have become increasingly affordable over the past decade, it is now possible to design and build a cost-effective system for monitoring the Earth's natural magnetic field variations, in particular for space weather events. Modern fluxgate magnetometers are sensitive down to the sub-nanotesla level, which far exceeds the level of accuracy required to detect very small variations of the external magnetic field. When the popular Raspberry Pi single-board computer is combined with a suitable digitiser it can be used as a low-cost data logger. We adapted off-the-shelf components to design a magnetometer system for schools and developed bespoke Python software to build a network of low-cost magnetometers across the UK. We describe the system and software and how it was deployed to schools around the UK. In addition, we show the results recorded by the systems from one of the largest geomagnetic storms of the current solar cycle.
GEM-MACH-PAH (rev2488): a new high-resolution chemical transport model for North American polycyclic aromatic hydrocarbons and benzene
Authors: Whaley Cynthia H. , Galarneau Elisabeth , Makar Paul A. , Akingunola Ayodeji , Gong Wanmin , Gravel Sylvie , Moran Michael D. , Stroud Craig , Zhang Junhua , Zheng Qiong
Published: July 2018

Abstract. Environment and Climate Change Canada's online air quality
forecasting model, GEM-MACH, was extended to simulate atmospheric
concentrations of benzene and seven polycyclic aromatic hydrocarbons (PAHs):
phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene,
and benzo(a)pyrene. In the expanded model, benzene and PAHs are emitted from
major point, area, and mobile sources, with emissions based on recent
emission factors. Modelled PAHs undergo gas–particle partitioning (whereas
benzene is only in the gas phase), atmospheric transport, oxidation, cloud
processing, and dry and wet deposition. To represent PAH gas–particle
partitioning, the Dachs–Eisenreich scheme was used, and we have improved
gas–particle partitioning parameters based on an empirical analysis to get
significantly better gas–particle partitioning results than the previous
North American PAH model, AURAMS-PAH. Added process parametrizations include
the particle phase benzo(a)pyrene reaction with ozone via the Kwamena scheme
and gas-phase scavenging of PAHs by snow via vapour sorption to the snow
surface. The resulting GEM-MACH-PAH model was used to generate the first online model
simulations of PAH emissions, transport, chemical transformation,
and deposition for a high-resolution domain (2.5 km grid cell spacing) in North
America, centred on the PAH data-rich region of southern Ontario, Canada and
the northeastern US. Model output for two seasons was compared to
measurements from three monitoring networks spanning Canada and the US
Average spring–summertime model results were found to be statistically
unbiased from measurements of benzene and all seven PAHs. The same was true
for the fall–winter seasonal mean, except for benzo(a)pyrene, which had a
statistically significant positive bias. We present evidence that the
benzo(a)pyrene results may be ameliorated via further improvements to
particulate matter and oxidant processes and transport. Our analysis focused
on four key components to the prediction of atmospheric PAH levels: spatial
variability, sensitivity to mobile emissions, gas–particle partitioning, and
wet deposition. Spatial variability of PAHs ∕ PM2.5 at a 2.5 km resolution
was found to be comparable to measurements. Predicted ambient surface
concentrations of benzene and the PAHs were found to be critically dependent
on mobile emission factors, indicating the mobile emissions sector has a
significant influence on ambient PAH levels in the study region. PAH wet
deposition was overestimated due to additive precipitation biases in the
model and the measurements. Our overall performance evaluation suggests that
GEM-MACH-PAH can provide seasonal estimates for benzene and PAHs and is
suitable for emissions scenario simulations.
A hybrid GCM paleo ice-sheet model, ANICE2.1 –
HadCM3@Bristolv1.0: set up and benchmark experiments
Authors: Berends Constantijn J. , de Boer Bas , van de Wal Roderik S. W.
Published: July 2018

Abstract. Fully coupled ice-sheet-climate modelling over 10,000–100,000-year time scales on high spatial and temporal resolution remains beyond the capability of current computational systems. Hybrid GCM-ice-sheet modelling offers a middle ground, balancing the need to accurately capture both long-term processes, in particular circulation driven changes in precipitation, and processes requiring a high spatial resolution like ablation. Here, we present and evaluate a model set-up that forces the ANICE 3D thermodynamic ice-sheet-shelf model calculating all ice on Earth, with pre-calculated output from several steady-state simulations with the HadCM3 general circulation model (GCM), using a so-called matrix method of coupling both components, where simulations with various levels of pCO2 and ice-sheet configuration are combined to form a time-continuous transient climate forcing consistent with the modelled ice-sheets. We address the difficulties in downscaling low-resolution GCM output to the higher-resolution grid of an ice-sheet model, and account for differences between GCM and ice-sheet model surface topography ranging from interglacial to glacial conditions. As a benchmark experiment to assess the validity of this model set-up, we perform a simulation of the entire last glacial cycle, from 120 kyr ago to present-day. The simulated eustatic sea-level drop at the Last Glacial maximum (LGM) for the combined Antarctic, Greenland, Eurasian and North-American ice-sheets amounts to 100 m, in line with many other studies. The simulated ice-sheets at LGM agree well with the ICE-5G reconstruction and the more recent DATED-1 reconstruction in terms of total volume and geographical location of the ice sheets. Moreover, modelled benthic oxygen isotope abundance and the relative contributions from global ice volume and deep-water temperature agree well with available data, as do surface temperature histories for the Greenland and Antarctic ice-sheets. This model strategy can be used to create time-continuous ice-sheet distribution and sea-level reconstructions for geological periods up to several millions of years in duration, capturing climate model driven variations in the mass balance of the ice sheet.
Managed aquifer recharge with reverse-osmosis desalinated seawater: modeling the spreading in groundwater using stable water isotopes
Authors: Ganot Yonatan , Holtzman Ran , Weisbrod Noam , Bernstein Anat , Siebner Hagar , Katz Yoram , Kurtzman Daniel
Published: July 2018

Abstract. The spreading of reverse-osmosis desalinated seawater (DSW) in the Israeli Coastal Aquifer was studied using groundwater modeling and stable water isotopes as tracers. The DSW produced at the Hadera seawater reverse osmosis (SWRO) desalination plant is recharged into the aquifer through infiltration pond at the managed aquifer recharge (MAR) site of Menashe, Israel. The distinct difference in isotope composition between DSW (δ18O = +1.41; δ2H = +11.34 ‰) and the natural groundwater (δ18O = −4.48 to −5.43 ‰; δ2H = −18.41 to −22.68 ‰) makes the water isotopes a preferable tracer compared to widely-used chemical tracers, such as chloride. Moreover, this distinct difference can be used to simplify the system to a binary mixture of two end members: desalinated seawater and groundwater. This approach is especially robust when spatial data of stable water isotopes in the aquifer is scarce. A calibrated groundwater flow and transport model was used to predict the DSW plume distribution in the aquifer after 50 years of MAR with DSW. The results show that after 50 years 94 % of the recharged DSW was recovered by the production wells at the Menashe MAR site. The presented methodology is useful for predicting the distribution of reverse-osmosis desalinated seawater in various downstream groundwater systems.