bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing Forecasting Model in Thailand Fashion Market Based on Statistical Analysis and Content-Based Image Retrieval
Authors: Kawinakrathiti Komaek , Phimoltares Suphakant , Utiswannakul Patcha
Published: August 2015

Traditional trend forecasting process in Thailand fashion industry was challenged by a fast fashion. In this paper, the Content-Based Image Retrieval (CBIR) technique is utilized for retrieval of a fashion trendsetter in fast fashion influence. Firstly, six fashion theories were implemented as 12 variables affecting the trendsetter. Cluster analysis, and factor analysis approach were used to find out the source of a fashion trendsetter as well. Cluster analysis separated all samples into three groups with different fashion ways. Moreover, factor analysis technique grouped all variables into three important factors. From such techniques, Internet media clearly is the best source of a fashion trendsetter. In the authors' model, traditional forecasting sources were added up with a fast fashion influence from CBIR. Then, the CBIR was evaluated in terms of efficiency compared with a real fashion expert in the Thai fashion industry. From statistical test, spatial color distribution yields high efficiency in selecting similar fashion style as a fashion expert.
Reducing Tracking Error in RFID Real-Time Localization Systems Using Kalman Filters
Authors: Sanda Benjamin , Abdel-Qader Ikhlas , Akanmu Abiola
Published: August 2015

The use of Radio Frequency Identification (RFID) has become widespread in industry as a means to quickly and wirelessly identify and track packages and equipment. Now there is a commercial interest in using RFID to provide real-time localization. Efforts to use RFID technology in this way experience localization errors due to noise and multipath effects inherent to these environments. This paper presents the use of both linear Kalman filters and non-linear Unscented Kalman filters to reduce the error rate inherent to real-time RFID localization systems and provide more accurate localization results in indoor environments. A commercial RFID localization system designed for use by the construction industry is used in this work, and a filtering model based on 3rd order motion is developed. The filtering model is tested with real-world data and shown to provide an increase in localization accuracy when applied to both raw time of arrival measurements as well as final localization results.
An Approach based on Social Bees for an Intrusion Detection System by Scenario
Authors: Lokbani Ahmed Chaouki , Lehireche Ahmed , Hamou Reda Mohamed , Boudia Mohamed Amine
Published: August 2015

The aim of the authors' work is to model the intrusion detection system by scenario with a bio-inspired method in this case the system of protection of social bees. The natural pattern of social bees produces security efficiency by its three filters. In this paper, the authors focus on scenario approach they chose as a strategy to intrusion odor recognition of bees. They propose a new philosophy based on limited responsibility for each agent. This proposition aims to better exploit the performance of their hardware, and to use intelligently a kddcup'99 corpus.
Social Media Marketing in Luxury Retail
Authors: De Souza Izabella M , Ferris Sharmila Pixy
Published: August 2015

This study examines the potentials of social media marketing for luxury retailers. Social media marketing tactics of three luxury retail brands (Barneys New York, Net-a-Porter.com, and Saks Fifth Avenue) were examined across three major social media sites (Facebook, Twitter and Instagram). All posts by the three retailers' posts on Facebook, Twitter and Instagram were recorded on over the course of a week. A content analysis revealed that different social media networks may be effectively used in different ways by luxury retailers. Facebook allows for the greatest connection with consumers (all three retailers had the most followers on Facebook) while Twitter allows for the largest volume of posts; consumer feedback was highest on Instagram. Overall, social media marketing proved an effective, low-cost tool for the three retailers, with payoff well justifying the effort. For example, all three retailers had over 1,200 shares and retweets on Facebook and Twitter.
Social Media
Authors: Kudeshia Chetna , Mittal Arun
Published: August 2015

From Obama's success to the Arab spring, from Kolaveri Di in India to Gangnam style, social media is omnipresent. We no longer go to the news, news finds us; we no longer visit merchandise, merchandise find us; social media has shrunk the globe beyond imagination. Social media is based on the combined notion of influence and participation -.tools that synchronize their voice with the company's voice and that combined voice affects the next customer. The development of social media networks have made it feasible for the customers to speak to thousands of other customers concerning a particular brand or a company. This communication between one to several additionally referred to as word-of-mouth marketing, isn't new to marketing, but the distinction is that currently these communications are on the far side boundaries. With the growing effect of social media on consumer buying behavior, it becomes imperative for a business to understand the competitive advantages of assorted social media avenues across diverse markets. As the world of online marketing is continuously progressing, the marketers must understand how these changes may influence buyer practices, and consequently promotional programs and strategies. Choices on how and when to successfully use the traditional as well as the social media alternatives require careful thought and consideration. This paper aims to throw light on the recent social media marketing strategies and demonstrates how this platform of online networking helps organizations to captivate their clients in a finer manner, thus building a stronger relationship with them. Also the present paper offers significant understanding to the marketers in knowing the vital role social media marketing plays in the formation of a strong brand. The present paper is conceptual in nature, and through the intensive literature review identifies the latest social media practices being adopted by the 21st century marketers. The study is an endeavor to see how advertisers are utilizing social networking as a strategic tool for advancement. The study finds that enhanced presence and communication on various social media channels help the firms in creating a better brand image while reducing promotional budgets. The paper additionally indicates how the exceptional attributes of correspondence by means of online networking help organizations not only in building a superior connection with their customers but also in converting them into their brand advocates. Thus, these network platforms are helping the businesses to engage with the purchasers, influencing them, connecting with them and finally changing them into their evangelists.
Biblical Spirituality and transformation
Authors: Lombaard Christo
Published: August 2015

Transformation is one of the key elements of the human spirituality phenomenon and is one of the foundational areas of study within the discipline of Christian Spirituality. Transformation entails the meaningful, deep changes within individuals as they are touched by the Holy and as they mature in their experience of and expression given to their faith. This article places that dynamism within the framework of the academic discipline of Biblical Spirituality, which is briefly described in the first part. After depicting the concept of transformation in some detail, its relationship with and its occurrence in the Bible are outlined.Bybelse Spiritualiteit en Transformasie. Transformasie is een van die sleutelelemente binne die menslike spiritualiteitsverskynsel en is een van die grondbeginsels van die studieveld binne die Christelike Spiritualiteitskunde. Transformasie behels betekenisvolle en diepgaande verandering in individue namate hulle deur die Heilige aangeraak word, groei in die belewenis van hulle geloof en hoe uitdrukking daaraan gegee word. Hierdie artikel plaas dié dinamiek binne die raamwerk van die akademiese dissipline van die Bybelse Spiritualiteit wat kortliks in die eerste gedeelte beskryf word. Nadat die transformasiekonsep in redelike besonderhede uiteengesit is, word die verwantskap daarvan aan, en die voorkoms daarvan in die Bybelomskryf.
Association of Serum Magnesium Deficiency with Insulin Resistance in Type 2 Diabetes Mellitus
Authors: Chutia Happy , Lynrah Kyrshanlang G
Published: August 2015

Background: Insulin resistance (IR) is the key pathophysiological defect that leads to the development of type 2 diabetes mellitus. The purpose of this study was to estimate serum magnesium level and insulin sensitivity indices among type 2 diabetes mellitus patients and to see an association between them.

Methods: This study was carried out among 38 type 2 diabetic patients and forty age and sex matched controls. Serum fasting glucose, magnesium, insulin, urea, and creatinine levels were estimated. Insulin sensitivity indices, homeostasis model assessment for insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) levels were calculated as per formulae.

Results: A highly significant low serum magnesium level was found in diabetic subjects as compared to the controls. Statistically significant high HOMA levels (>2.6) and low QUICKI levels (< 0.33) were found among the case group. An inverse, statistically significant correlation was found between serum magnesium and fasting insulin level. A highly statistically significant inverse correlation was found between serum magnesium and HOMA level, and a positive correlation was found between serum magnesium and QUICKI level, that is, serum magnesium level decreases with increase in IR. A strong association was also found between fasting serum insulin level and insulin sensitivity indices.

Conclusion: This study showed a lower serum magnesium level in diabetic patients compared to control. A strong association was also found between serum magnesium level and insulin sensitivity indices. For proper management of type 2 diabetes, it may, therefore, be necessary to treat hypomagnesemia in these patients.
Clinicomycological Study of Dermatophytosis in South India
Authors: Poluri Lakshmi Vasantha , Indugula Jyothi P , Kondapaneni Sai L
Published: August 2015

Introduction: Dermatophytic infections are commonly encountered a problem and constitute more than 50% of cases in dermatology outpatient departments. Diagnosis of these infections requires the proper use of laboratory methods.

Objectives: This study was conducted to know the etiology of dermatophytosis in patients attending Tertiary Care Level Hospital in South India and to compare the efficacy of Sabouraud’s dextrose agar (SDA) with actidione and dermatophyte test medium (DTM) in isolating and identifying dermatophytes.

Materials and Methods: A total of 110 samples which included 101 skin samples and 9 hair samples from clinically suspected dermatophytosis were collected. Direct microscopy by KOH and culture on SDA with actidione and DTM were done.

Results: Of 110 samples collected, 58.18% were KOH positive for fungal filaments and 56.36% were culture positive for dermatophytes. More number of cases were observed between age groups of 21–40 years. Males were more affected compared to females. Tinea corporis was the common clinical presentation observed (40%). Trichophyton rubrum (58.06%) was the predominant isolate recovered in all clinical presentations but Trichophyton violaceum was the most common isolate in tinea capitis. All culture positives were grown on both SDA with actidione and DTM. Appearance of growth was earlier on DTM that is, within 10 days compared to SDA with actidione where growth started appearing only after 10 days. This is statistically significant P < 0.0001 (X
2 = 71.6). Species level identification on primary isolation was possible when grown on SDA with actidione and it was not possible with the growth on DTM on primary isolation.

Conclusion: DTM is a good screening medium in laboratory diagnosis of dermatophytosis when compared to SDA with actidione. But DTM is inferior to SDA with actidione in identification of dermatophyte species.
Etiology of Pancytopenia: An Observation from a Referral Medical Institution of Eastern Region of India
Authors: Dasgupta Senjuti , Mandal Prakas K , Chakrabarti Sudipta
Published: August 2015

Background: Pancytopenia is a relatively common hematological condition, the etiological factors of which vary widely in different geographic location. Determining the specific etiology is of immense importance for appropriate management. Aims and Objectives: The present study was undertaken to delineate etiological factors leading to pancytopenia in a Tertiary Care Hospital of West Bengal from Eastern Region of India.

Aims and Objectives:The present study was undertaken to delineate etiological factors leading to pancytopenia in a Tertiary Care Hospital of West Bengal from Eastern Region of India.

Materials and Methods: A prospective study was conducted for a period of 2 years in which 248 patients were included. After obtaining a relevant clinical history, physical examination was done followed by complete blood count including peripheral blood smears examination, relevant biochemical, and radiological investigations. Afterward, bone marrow aspiration and biopsy were performed and microscopically examined.

Results: Among 248 patients studied, 156 (62.9%) were males and 92 (37.09%) were females. The mean age of the patients was 33 years. Aplastic anemia was the most common cause of pancytopenia that was observed in 83 cases (33.47%) followed by megaloblastic anemia in 52 cases (20.97%), leishmaniasis in 34 patients (13.71%), hypersplenism also in 34 patients (13.71%), and tuberculosis and other connective tissue disorders in 18 cases (7.26%). The occurrence of aplastic anemia was statistically significant in pediatric (≤15 years) age group.

Conclusion: Aplastic anemia was found to be the most common cause of pancytopenia in this study, which is in contrast to studies conducted from other regions of India. Delineation of etiologies of pancytopenia in various regions can help in defining diagnostic and therapeutic strategies, which is expected to contribute toward the better management of such patients.
Laboratory studies of collection efficiency of sub-micrometer aerosol particles by cloud droplets on a single-droplet basis
Authors: Ardon-Dryer K. , Huang Y.-W. , Cziczo D. J.
Published: August 2015

Abstract. An experimental setup has been constructed to measure the collection efficiency (CE) of sub-micrometer aerosol particles by cloud droplets. Droplets of a dilute aqueous ammonium sulfate solution with an average radius of 21.6 μm fall freely into a chamber and collide with sub-micrometer polystyrene latex (PSL) sphere particles of known sizes and concentrations. Two relative humidity (RH) conditions, 15 ± 3 % and 88 ± 3 %, hereafter termed "low" and "high", respectively, were varied with different particles sizes and concentrations. After passing through the chamber, the droplets and aerosol particles were sent to the Particle Analysis by Laser Mass Spectrometry (PALMS) instrument to determine chemical compositions on a single-droplet basis. "Coagulated droplets" (droplets that collected aerosols) had mass spectra that contained signatures from both an aerosol particle and a droplet residual. CE values range from 2.0 × 10−1 to 1.6 for the low-RH case and from 1.5 × 10−2 to 9.0 × 10−2 for the high-RH case. CE values were, within experimental uncertainty, independent of the aerosol concentrations. CE values in this study were found to be in agreement with previous experimental and theoretical studies. To our knowledge, this is the first collection experiment performed on a single-droplet basis with atmospherically relevant conditions such as droplet sizes, droplet charges and flow.
Dust–air pollution dynamics over the eastern Mediterranean
Authors: Abdelkader M. , Metzger S. , Mamouri R. E. , Astitha M. , Barrie L. , Levin Z. , Lelieveld J.
Published: August 2015

Abstract. Interactions of desert dust and air pollution over the eastern Mediterranean (EM) have been studied, focusing on two distinct dust transport events on 22 and 28 September 2011. The atmospheric chemistry–climate model EMAC has been used at about 50 km grid spacing, applying an online dust emission scheme and calcium as a proxy for dust reactivity. EMAC includes a detailed tropospheric chemistry mechanism, aerosol microphysics and thermodynamics schemes to describe dust "aging". The model is evaluated using ground-based observations for aerosol concentrations and aerosol optical depth (AOD) as well as satellite observations. Simulation results and back trajectory analysis show that the development of synoptic disturbances over the EM can enhance dust transport from the Sahara and Arabian deserts in frontal systems that also carry air pollution to the EM. The frontal systems are associated with precipitation that controls the dust removal. Our results show the importance of chemical aging of dust, which increases particle size, dust deposition and scavenging efficiency during transport, overall reducing the lifetime relative to non-aged dust particles. The relatively long travel periods of Saharan dust result in more sustained aging compared to Arabian dust. Sensitivity simulations indicate 3 times more dust deposition of aged relative to pristine dust, which significantly decreases the dust lifetime and loading.
Numerical study of upper hybrid to Z-mode leakage during electromagnetic pumping of groups of striations in the ionosphere
Authors: Eliasson B. , Leyser T. B.
Published: August 2015

Abstract. We investigate numerically the interaction between ionospheric magnetic field-aligned density striations and a left-hand circularly polarized (L)-mode wave. The L-mode wave is scattered into upper hybrid (UH) waves which are partially trapped in the striations, but leak energy to electromagnetic waves in the Z-mode branch. For small-amplitude (1 %) striations, this loss mechanism leads to a significant reduction in amplitude of the UH waves. For several striations organized in a lattice, the leaking of Z-mode waves is compensated by influx of Z-mode radiation from neighboring striations, leading to an increased amplitude of the weakly trapped UH waves. For large-amplitude (10 %) striations the trapped UH waves rapidly increase in amplitude far beyond the threshold for parametric instabilities, and the Z-mode leakage is less important. The results have relevance for the growth of striations and the onset of UH and lower hybrid turbulence during electromagnetic high-frequency pumping of ionospheric plasma, which require large-amplitude UH waves.
Observation of a new type of low-frequency waves at comet 67P/Churyumov-Gerasimenko
Authors: Richter I. , Koenders C. , Auster H.-U. , Frühauff D. , Götz C. , Heinisch P. , Perschke C. , Motschmann U. , Stoll B. , Altwegg K. , Burch J. , Carr C. , Cupido E. , Eriksson A. , Henri P. , Goldstein R. , Lebreton J.-P. , Mokashi P. , Nemeth Z. , Nilsson H. , Rubin M. , Szegö K. , Tsurutani B. T. , Vallat C. , Volwerk M. , Glassmeier K.-H.
Published: August 2015

Abstract. We report on magnetic field measurements made in the innermost coma of 67P/Churyumov-Gerasimenko in its low-activity state. Quasi-coherent, large-amplitude (δ B/B ~ 1), compressional magnetic field oscillations at ~ 40 mHz dominate the immediate plasma environment of the nucleus. This differs from previously studied cometary interaction regions where waves at the cometary ion gyro-frequencies are the main feature. Thus classical pickup-ion-driven instabilities are unable to explain the observations. We propose a cross-field current instability associated with newborn cometary ion currents as a possible source mechanism.
Are recent changes in sediment manganese sequestration in the euxinic basins of the Baltic Sea linked to the expansion of hypoxia?
Authors: Lenz C. , Jilbert T. , Conley D.J. , Wolthers M. , Slomp C.P.
Published: August 2015

Abstract. Expanding hypoxia in the Baltic Sea over the past century has led to the development of anoxic and sulfidic (euxinic) deep basins that are only periodically ventilated by inflows of oxygenated waters from the North Sea. In this study, we investigate the potential consequences of the expanding hypoxia for manganese (Mn) burial in the Baltic Sea using a combination of pore water and sediment analyses of dated sediment cores from eight locations. Diffusive fluxes of dissolved Mn from sediments to overlying waters at oxic, hypoxic and euxinic sites are consistent with an active release of Mn from these areas. Although the present-day fluxes are significant (ranging up to ca. 240 μmol m−2 d−1), comparison to published water column data suggests that the current benthic release of Mn is small when compared to the large pool of Mn already present in the hypoxic and anoxic water column. Our results highlight two modes of Mn carbonate formation in sediments of the deep basins. In the Gotland Deep area, Mn carbonates likely form from Mn oxides that are precipitated from the water column directly following North Sea inflows. In the Landsort Deep, in contrast, Mn carbonate and Mn sulfide layers appear to form independently of inflow events, and are possibly related to the much larger and continuous input of Mn oxides linked to sediment focusing. Whereas Mn-enriched sediments continue to accumulate in the Landsort Deep, this does not hold for the Gotland Deep area. Here, a recent increase in euxinia, as evident from measured bottom water sulfide concentrations and elevated sediment molybdenum (Mo), coincides with a decline in sediment Mn content. Sediment analyses also reveal that recent inflows of oxygenated water (since ca. 1995) are no longer consistently recorded as Mn carbonate layers. Our data suggest that eutrophication has not only led to a recent rise in sulfate reduction rates but also to a decline in reactive Fe input to these basins. We hypothesize that these factors have jointly led to higher sulfide availability near the sediment–water interface after inflow events. As a consequence, the Mn oxides may be reductively dissolved more rapidly than in the past and Mn carbonates may no longer form. Using a simple diagenetic model for Mn dynamics in the surface sediment, we demonstrate that an enhancement of the rate of reduction of Mn oxides is consistent with such a scenario. Our results have important implications for the use of Mn carbonate enrichments as a redox proxy in marine systems.
Macroalgae contribute to nested mosaics of pH variability in a subarctic fjord
Authors: Krause-Jensen D. , Duarte C. M. , Hendriks I. E. , Meire L. , Blicher M. E. , Marbà N. , Sejr M. K.
Published: August 2015

Abstract. The Arctic Ocean is considered the most vulnerable ecosystem to ocean acidification, and large-scale assessments of pH and the saturation state for aragonite (Ωarag) have led to the notion that the Arctic Ocean is already close to a corrosive state. In high-latitude coastal waters the regulation of pH and Ωarag is, however, far more complex than offshore because increased biological activity and input of glacial meltwater affect pH. Effects of ocean acidification on calcifiers and non-calcifying phototrophs occupying coastal habitats cannot be derived from extrapolation of current and forecasted offshore conditions, but they require an understanding of the regimes of pH and Ωarag in their coastal habitats. To increase knowledge of the natural variability in pH in the Arctic coastal zone and specifically to test the influence of benthic vegetated habitats, we quantified pH variability in a Greenland fjord in a nested-scale approach. A sensor array logging pH, O2, PAR, temperature and salinity was applied on spatial scales ranging from kilometre scale across the horizontal extension of the fjord; to 100 m scale vertically in the fjord, 10–100 m scale between subtidal habitats with and without kelp forests and between vegetated tidal pools and adjacent vegetated shores; and to centimetre to metre scale within kelp forests and millimetre scale across diffusive boundary layers of macrophyte tissue. In addition, we assessed the temporal variability in pH on diurnal and seasonal scales. Based on pH measurements combined with point samples of total alkalinity, dissolved inorganic carbon and relationships to salinity, we also estimated variability in Ωarag. Results show variability in pH and Ωarag of up to 0.2–0.3 units at several scales, i.e. along the horizontal and vertical extension of the fjord, between seasons and on a diel basis in benthic habitats and within 1 m3 of kelp forest. Vegetated intertidal pools exhibited extreme diel pH variability of > 1.5 units and macrophyte diffusive boundary layers a pH range of up to 0.8 units. Overall, pelagic and benthic metabolism was an important driver of pH and Ωarag producing mosaics of variability from low levels in the dark to peak levels at high irradiance generally appearing favourable for calcification. We suggest that productive coastal environments may form niches of high pH in a future acidified Arctic Ocean.
Fundamental molecules of life are pigments which arose and co-evolved as a response to the thermodynamic imperative of dissipating the prevailing solar spectrum
Authors: Michaelian K. , Simeonov A.
Published: August 2015

Abstract. The driving force behind the origin and evolution of life has been the thermodynamic imperative of increasing the entropy production of the biosphere through increasing the global solar photon dissipation rate. In the upper atmosphere of today, oxygen and ozone derived from life processes are performing the short-wavelength UV-C and UV-B dissipation. On Earth's surface, water and organic pigments in water facilitate the near-UV and visible photon dissipation. The first organic pigments probably formed, absorbed, and dissipated at those photochemically active wavelengths in the UV-C and UV-B that could have reached Earth's surface during the Archean. Proliferation of these pigments can be understood as an autocatalytic photochemical process obeying non-equilibrium thermodynamic directives related to increasing solar photon dissipation rate. Under these directives, organic pigments would have evolved over time to increase the global photon dissipation rate by (1) increasing the ratio of their effective photon cross sections to their physical size, (2) decreasing their electronic excited state lifetimes, (3) quenching radiative de-excitation channels (e.g., fluorescence), (4) covering ever more completely the prevailing solar spectrum, and (5) proliferating and dispersing to cover an ever greater surface area of Earth. From knowledge of the evolution of the spectrum of G-type stars, and considering the most probable history of the transparency of Earth's atmosphere, we construct the most probable Earth surface solar spectrum as a function of time and compare this with the history of molecular absorption maxima obtained from the available data in the literature. This comparison supports the conjecture that many fundamental molecules of life are pigments which arose, proliferated, and co-evolved as a response to dissipating the solar spectrum, supports the thermodynamic dissipation theory for the origin of life, constrains models for Earth's early atmosphere, and sheds some new light on the origin of photosynthesis.
Reconsidering the role of carbonate ion concentration in calcification by marine organisms
Authors: Bach L. T.
Published: August 2015

Abstract. Marine organisms precipitate 0.5–2.0 Gt of carbon as calcium carbonate (CaCO3) every year with a profound impact on global biogeochemical element cycles. Biotic calcification relies on calcium ions (Ca2+) and usually on bicarbonate ions (HCO3−) as CaCO3 substrates and can be inhibited by high proton (H+) concentrations. The seawater concentration of carbonate ions (CO32−) and the CO32−-dependent CaCO3 saturation state (ΩCaCO3) seem to be irrelevant in this production process. Nevertheless, calcification rates and the success of calcifying organisms in the oceans often correlate surprisingly well with these two carbonate system parameters. This study addresses this dilemma through the rearrangement of carbonate system equations which revealed an important proportionality between [CO32−] or ΩCaCO3and the ratio of [HCO3−] to [H+]. Due to this proportionality, calcification rates will always correlate as well with [HCO3−] / [H+] as they do with [CO32−] or ΩCaCO3 when temperature, salinity, and pressure are constant. Hence, [CO32−] and ΩCaCO3 may simply be very good proxies for the control by [HCO3−] / [H+], where [HCO3−] serves as the inorganic carbon substrate and [H+] functions as a calcification inhibitor. If the "substrate–inhibitor ratio" (i.e., [HCO3−] / [H+]) rather than [CO32−] or ΩCaCO3 controls biotic CaCO3 formation, then some of the most common paradigms in ocean acidification research need to be reviewed. For example, the absence of a latitudinal gradient in [HCO3−] / [H+] in contrast to [CO32−] and ΩCaCO3 could modify the common assumption that high latitudes are affected most severely by ocean acidification.
Biogeochemistry of a large and deep tropical lake (Lake Kivu, East Africa: insights from a stable isotope study covering an annual cycle
Authors: Morana C. , Darchambeau F. , Roland F. A. E. , Borges A. V. , Muvundja F. , Kelemen Z. , Masilya P. , Descy J.-P. , Bouillon S.
Published: August 2015

Abstract. During this study, we investigated the seasonal variability of the concentration and the stable isotope composition of several inorganic and organic matter (OM) reservoirs in the large, oligotrophic and deep tropical Lake Kivu (East Africa). Data were acquired over 1 year at a fortnightly temporal resolution. The δ13C signature of the dissolved inorganic carbon (DIC) increased linearly with time during the rainy season, then suddenly decreased during the dry season due to vertical mixing with 13C-depleted DIC waters. The δ13C signature of the particulate organic carbon pool (POC) revealed the presence of a consistently abundant methanotrophic biomass in the oxycline throughout the year. We also noticed a seasonal shift during the dry season toward higher values in the δ15N of particulate nitrogen (PN) in the mixed layer and δ15N-PN was significantly related to the contribution of cyanobacteria to the phytoplankton assemblage, suggesting that rainy season conditions could be more favourable to atmospheric nitrogen-fixing cyanobacteria. Finally, zooplankton were slightly enriched in 13C compared to the autochthonous POC pool, and the δ15N signature of zooplankton followed well the seasonal variability in δ15N-PN, consistently 3.0 ± 1.1 ‰ heavier than the PN pool. Together, δ13C and δ15N analysis suggests that zooplankton directly incorporate algal-derived OM in their biomass, and that they rely almost exclusively on this source of OM throughout the year in general agreement with the very low allochthonous OM inputs from rivers in Lake Kivu.
Seasonal, sub-seasonal and spatial fluctuations in oxygen-depleted bottom waters in an embayment of an eastern boundary upwelling system: St Helena Bay
Authors: Pitcher G. C. , Probyn T. A.
Published: August 2015

Abstract. The considerable impact of oxygen deficient waters on marine resources in St Helena Bay has generated interest in exploring the vulnerability of South Africa's largest and most productive bay to further deoxygenation in response to climate change. Seasonal, sub-seasonal and spatial fluctuations in bottom dissolved oxygen (DO) are examined in St Helena Bay to facilitate better interpretation of historical data. DO measurements in relation to physical, chemical and biological variables were made between November 2013 and November 2014. Alongshore bay characteristics were assessed through comparison of variables along the 50 m depth contour. A mean coefficient of variation of 0.35 provided a measure of the relative variability of near-bottom DO concentrations along this contour. Across-shelf transects captured the seasonal development of hypoxia in relation to the distribution of phytoplankton biomass. DO was lowest in autumn in the south of the bay prior to winter ventilation of the bottom waters. Exceptional dinoflagellate blooms forming extensive subsurface thin layers preceded the autumn DO minima. The development of hypoxia at inner and central stations prior to expansion beyond the boundaries of the bay provided evidence of local drawdown. Coincident with the seasonal decline of DO within the bay was an increase in macronutrient concentrations which tended to mirror DO concentrations. Indication of denitrification in the suboxic waters in the south of the bay was provided through evidence of a nitrate deficit in autumn supported by elevated nitrite concentrations. Superimposed on the seasonal decline of DO concentrations in the bottom waters were sub-seasonal events of hypoxia and anoxia linked to episodic deposition of organic matter as indicated by increases in bottom Chl a concentrations.
Using satellite data to improve the leaf phenology of a global Terrestrial Biosphere Model
Authors: MacBean N. , Maignan F. , Peylin P. , Bacour C. , Bréon F. -M. , Ciais P.
Published: August 2015

Abstract. Correct representation of seasonal leaf dynamics is crucial for Terrestrial Biosphere Models (TBMs), but many such models cannot accurately reproduce observations of leaf onset and senescence. Here we optimized the phenology-related parameters of the ORCHIDEE TBM using satellite-derived Normalized Difference Vegetation Index data (MODIS NDVI v5). We found the misfit between the observations and the model decreased after optimisation for all boreal and temperate deciduous Plant Functional Types, primarily due to an earlier onset of leaf senescence. The model bias was only partially reduced for tropical deciduous trees and no improvement was seen for natural C4 grasses. Spatial validation demonstrated the generality of the posterior parameters for use in global simulations, with an increase in global median correlation of 0.56 to 0.67. The simulated global mean annual GPP decreased by ~10 Pg C yr−1 over the 1990–2010 period due to the substantially shortened Growing Season Length (up to 30 days in the Northern Hemisphere), thus reducing the positive bias and improving the seasonal dynamics of ORCHIDEE compared to independent data-based estimates. Finally, the optimisations led to changes in the strength and location of the trends in the simulated GSL and mean annual fAPAR, suggesting care should be taken when using un-calibrated models in attribution studies. We suggest that the framework presented here can be applied for improving the phenology of all global TBMs.
Hydroxy fatty acids in fresh snow samples from northern Japan: long-range atmospheric transport of Gram-negative bacteria by Asian winter monsoon
Authors: Tyagi P. , Yamamoto S. , Kawamura K.
Published: August 2015

Abstract. Hydroxy fatty acids (FAs) in fresh snow from Sapporo, one of the heaviest snowfall regions in the world, have been studied to ascertain the airborne bacterial endotoxin concentrations and their biomass. The presence of β-hydroxy FAs (C9–C28), constituents of Gram-negative bacteria (GNB), suggests long-range transport of soil microbes. Likewise, the occurrence of α- and ω-hydroxy FAs (C9–C30 and C9–C28, respectively) in snow reveals their contribution from epicuticular waxes and soil microorganisms. Estimated endotoxin and GNB mass can aid in assessing their possible impacts on the diversity and functioning of aquatic and terrestrial ecosystems, as well as lethal effects on pedestrians through dispersal of microbes. Air mass back trajectories together with hydroxy FAs unveil their sources from Siberia, Russian Far East and North China by the Asian monsoon. This study highlights the role of fresh snow that reduces the human health risk of GNB and endotoxin by scavenging from the air.
Technical Note: A generic law-of-the-minimum flux limiter for simulating substrate limitation in biogeochemical models
Authors: Tang J. Y. , Riley W. J.
Published: August 2015

Abstract. We present a generic flux limiter to account for mass limitations from an arbitrary number of substrates in a biogeochemical reaction network. The flux limiter is based on the observation that substrate (e.g., nitrogen, phosphorus) limitation in biogeochemical models can be represented as to ensure mass conservative and non-negative numerical solutions to the governing ordinary differential equations. Application of the flux limiter includes two steps: (1) formulate the biogeochemical processes with a matrix of stoichiometric coefficients and (2) apply Liebig's law of the minimum using the dynamic stoichiometric relationship of the reactants. This approach contrasts with the ad hoc down-regulation approaches that are implemented in many existing models (such as CLM4.5 and the ACME (Accelerated Climate Modeling for Energy) Land Model (ALM)) of carbon and nutrient interactions, which are error prone when adding new processes, even for experienced modelers. Through an example implementation with a Century-like decomposition model that includes carbon, nitrogen, and phosphorus, we show that our approach (1) produced almost identical results to that from the ad hoc down-regulation approaches under non-limiting nutrient conditions; and (2) properly resolved the negative solutions under substrate-limited conditions where the simple clipping approach failed; and (3) successfully avoided the potential conceptual ambiguities that are implied by those ad hoc down-regulation approaches. We expect our approach will make future biogeochemical models easier to improve and more robust.
Multi-time scale data assimilation for atmosphere–ocean state estimates
Authors: Steiger N. , Hakim G.
Published: August 2015

Abstract. Paleoclimate proxy data span seasonal to millennial time scales, and Earth's climate system has both high- and low-frequency components. Yet it is currently unclear how best to incorporate multiple time scales of proxy data into a single reconstruction framework and to also capture both high- and low-frequency components of reconstructed variables. Here we present a data assimilation algorithm that can explicitly incorporate proxy data at arbitrary time scales. Through a series of pseudoproxy experiments, we find that atmosphere–ocean states are most skilfully reconstructed by incorporating proxies across multiple time scales compared to using proxies at short (annual) or long (~ decadal) time scales alone. Additionally, reconstructions that incorporate long time-scale pseudoproxies improve the low-frequency components of the reconstructions relative to using only high-resolution pseudoproxies. We argue that this is because time averaging high-resolution observations improves their covariance relationship with the slowly-varying components of the coupled-climate system, which the data assimilation algorithm can exploit. These results are insensitive to the choice of climate model, despite the model variables having very different spectral characteristics. Our results also suggest that it may be possible to reconstruct features of the oceanic meridional overturning circulation based solely on atmospheric surface temperature proxies.
Evaluation of an operational ocean model configuration at 1/12° spatial resolution for the Indonesian seas – Part 2: Biogeochemistry
Authors: Gutknecht E. , Reffray G. , Gehlen M. , Triyulianti I. , Berlianty D. , Gaspar P.
Published: August 2015

Abstract. In the framework of the INDESO (Infrastructure evelopment of Space Oceanography) project, an operational ocean forecasting system was developed to monitor the state of the Indonesian seas in terms of circulation, biogeochemistry and fisheries. This forecasting system combines a suite of numerical models connecting physical and biogeochemical variables to population dynamics of large marine predators (tunas). The physical/biogeochemical coupled component (INDO12BIO configuration) covers a large region extending from the western Pacific Ocean to the Eastern Indian Ocean at 1/12° resolution. The OPA/NEMO physical ocean model and the PISCES biogeochemical model are coupled in "on-line" mode without degradation in space and time. The operational global ocean forecasting system (1/4°) operated by Mercator Ocean provides the physical forcing while climatological open boundary conditions are prescribed for the biogeochemistry. This paper describes the skill assessment of the INDO12BIO configuration. Model skill is assessed by evaluating a reference hindcast simulation covering the last 8 years (2007–2014). Model results are compared to satellite, climatological and in situ observations. Diagnostics are performed on chlorophyll a, primary production, mesozooplankton, nutrients and oxygen. Model results reproduce the main characteristics of biogeochemical tracer distributions in space and time. The seasonal cycle of chlorophyll a is in phase with satellite observations. The northern and southern parts of the archipelago present a distinct seasonal cycle, with higher chlorophyll biomass in the southern (northern) part during SE (NW) monsoon. Nutrient and oxygen concentrations are correctly reproduced in terms of horizontal and vertical distributions. The biogeochemical content of water masses entering in the archipelago as well as the water mass transformation across the archipelago conserves realistic vertical distribution in Banda Sea and at the exit of the archipelago.
Assessing various drought indicators in representing drought in boreal forests in Finland
Authors: Gao Y. , Markkanen T. , Thum T. , Aurela M. , Lohila A. , Mammarella I. , Hagemann S. , Aalto T.
Published: August 2015

Abstract. Droughts can impact on forest functioning and production, and even lead to tree mortality. However, drought is an elusive phenomenon that is difficult to quantify and define universally. In this study, we assessed the performance of a set of indicators that have been used to describe drought conditions in the summer months (June, July, August) over a 30 year period (1981–2010) in Finland. Those indicators include the Standardized Precipitation Index (SPI), the Standardized Precipitation–Evapotranspiration Index (SPEI), the Soil Moisture Index (SMI) and the Soil Moisture Anomaly (SMA). Herein, regional soil moisture was produced by the land surface model JSBACH. While SPI, SPEI, and SMA show a degree of anomalies from the statistical means over a period, SMI is directly connected to plant available water and closely dependent on soil properties. Moreover, the buffering effect of soil moisture and the associated soil moisture memory can impact on the onset and duration of drought as indicated by the SMI and SMA, whereas SPI and SPEI are directly controlled by meteorological conditions. In particular, we investigated whether the SMI, SMA and SPEI are able to indicate the Extreme Drought affecting Forest health (EDF) in Finland. EDF thresholds for these indicators are suggested, based on the spatially representative statistics of forest health observations in the exceptional dry year 2006. Our results showed that SMI was the best indicator in capturing the spatial extent of forest damage induced by the extreme drought in 2006. In addition, the derived thresholds were applied to those indicators to capture EDF events over the summer months of the 30 year study period. The SPEI and SMA showed more frequent EDF events over the 30 year period, and typically described a higher fraction of influenced area than SMI. In general, the suggested EDF thresholds for those indicators may be used for the indication of EDF events in Finland or other boreal forests areas in the context of future climate scenarios. However, the results have to be interpreted carefully, with due consideration of their different properties and the complexity of drought. Our results would suggest that in order to take appropriate precautions to mitigate against possible forest losses, an integrated analysis of projected drought with drought indicators is recommended.
Flash flood occurrence and relation to the rainfall hazard in a highly urbanized area
Authors: Papagiannaki K. , Lagouvardos K. , Kotroni V. , Bezes A.
Published: August 2015

Abstract. The paper examines the flash flood events that occurred over a decade in the Attica prefecture, the most urbanized region of Greece, with the aim of identifying triggering rainfall thresholds, as well as assessing the effect of rainfall upon the magnitude of the induced damages. The analysis incorporates rainfall records from a network of 28 surface meteorological stations and information on the spatial distribution of the flash flood events that is derived from the active database of damaging weather events maintained by the atmospheric modelling group of the National Observatory of Athens. The main findings concern firstly the relation between the flash flood impact, as measured by the fire service operations in flooded properties, and precipitation in various time intervals. In the period 2005–2014, 48 damaging flash flood events occurred in the target area and caused more than 3500 fire service operations in flooded properties. Most of the events are associated with maximum accumulated rainfall of more than 20 mm in 24 h and 3 mm in 10 min. However, the flash flood impact intensity, as measured by the number of the fire service operations per event, increases significantly above the levels of 60 mm in 24 h and 10 mm in 10 min. Secondly, graphs of rainfall intensity versus duration are developed for 15 sub-areas of Attica in order to define rainfall intensity thresholds for flood triggering at a more local level. It is shown that conclusions regarding the reliability of the estimated thresholds should take into account the representativity of the rain gauges, which is determined by the local network's density, the gauges' location and record length.
Impact of variable sea-water conductivity on motional induction simulated with an OGCM
Authors: Irrgang C. , Saynisch J. , Thomas M.
Published: August 2015

Abstract. Carrying high concentrations of dissolved salt, ocean water is a good electrical conductor. As sea-water flows through the Earth's ambient geomagnetic field, electric fields are generated, which in turn induce secondary magnetic fields. In current models for oceanic induced magnetic fields, a realistic consideration of sea-water conductivity is often neglected and the effect on the variability of the oceanic induced magnetic field unknown. To model magnetic fields that are induced by non-tidal global ocean currents, an electromagnetic induction model is implemented into the Ocean Model for Circulation and Tides (OMCT). This provides the opportunity to not only model oceanic induced magnetic signals, but to assess the impact of oceanographic phenomena on the induction process. In this paper, the sensitivity of the induction process due to spatial and temporal variations in sea-water conductivity is investigated. It is shown that assuming an ocean-wide uniform conductivity is insufficient to accurately capture the temporal variability of the magnetic signal. Using instead a realistic global sea-water conductivity distribution increases the temporal variability of the magnetic field up to 45 %. Especially vertical gradients in sea-water conductivity prove to be a key factor for the variability of the oceanic induced magnetic field. However, temporal variations of sea-water conductivity only marginally affect the magnetic signal.