bluuebunny/crossref_metadata_2025 huggingface dataset:
Comportamiento frente a la corrosión de fundiciones con grafito laminar y esferoidal parcialmente modificadas con silicio en NaCl 0,03 M
Authors: Arenas María Ángeles , Niklas Andrea , Conde Ana , Méndez Susana , Sertucha Jon , De Damborenea Juan José
Published: December 2014

El uso creciente de fundiciones esferoidales en aplicaciones tecnológicas hace que se busquen nuevos métodos para mejorar su comportamiento frente a la corrosión. Entre las distintas maneras de abordar este problema, la modificación de su composición química tiene un doble interés dado que, junto con un aumento en la resistencia frente a la corrosión, se pueden conseguir propiedades mecánicas mejoradas. Todo ello se debe conseguir, además, sin aumentar de manera significativa los costes de producción. En este trabajo se presentan los primeros resultados del comportamiento frente a la corrosión de una serie de fundiciones grafíticas de composición modificada. En el caso de las fundiciones esferoidales se ha variado el contenido de silicio con el fin de conocer el efecto de este elemento. Los resultados encontrados muestran una ligera mejora en la resistencia frente a la corrosión en aquellas aleaciones con alto contenido de silicio respecto a las fundiciones convencionales durante las primeras horas de ensayo para, posteriormente, mostrar un comportamiento similar. No obstante, es importante destacar que estas modificaciones no comprometen las propiedades mecánicas de las aleaciones base, lo que señala un camino para la preparación de nuevas fundiciones con un mayor contenido en elementos de aleación.
SIMPLIFIED WARFARIN DOSE–RESPONSE PHARMACODYNAMIC MODELS
Authors: Kim Seongho , Gaweda Adam E , Wu Dongfeng , Li Lang , Rai Shesh N , Brier Michael E
Published: December 2014

Warfarin is a frequently used oral anticoagulant for long-term prevention and treatment of thromboembolic events. Due to its narrow therapeutic range and large inter-individual dose–response variability, it is highly desirable to personalize warfarin dosing. However, the complexity of the conventional kinetic-pharmacodynamic (K-PD) models hampers the development of the personalized dose management. To avert this challenge, we propose simplified PD models for warfarin dose-INR response relationship, which is motivated by ideas from control theory. The simplified models were further applied to longitudinal data of 37 patients undergoing anticoagulation treatment using the standard two-stage approach and then compared with the conventional K-PD models. Data analysis shows that all models have a similar predictive ability, but the simplified models are most parsimonious.
Equitable and Sustainable Development of Foreign Land Acquisitions
Authors: Asongu Simplice A. , Nguena Christian L.
Published: December 2014

Large-scale agricultural land acquisitions have been covered substantially in recent literature. Despite the wealth of theoretical and empirical studies on this subject, there is no study that has reviewed existing literature in light of concerns over sustainable and equitable management. This chapter fills the gap by analyzing and synthesizing available literature to put some structure on existing knowledge. The chapter makes a threefold contribution to the literature. First, it takes stock of what we know so far about the determinants of land grab. Second, it presents a picture of sustainable and equitable development of foreign land acquisitions. Third, policy syndromes are examined and policy implications discussed. Based on the accounts, the issues are not about whether agricultural investments are needed but about how they can be sustainably and equitably managed to make positive contributions to food security and domestic development.
Implications of Foreign Land Acquisitions in Sub-Saharan Africa
Authors: Onwuemele Andrew
Published: December 2014

The acquisition of vast tracts of land by private investors now referred to as land grabbing became a widespread phenomenon after 2007. The nature and magnitude of these acquisitions have led to widespread debate about its positive and negative impacts on local communities. This chapter provides recent empirical thinking on the implications of foreign land acquisitions in Africa. The chapter, among others, reveals that foreign land acquisitions have both positive and negative consequences for Africa. For instance, while it was widely demonstrated that it improves access to capital and technology for increased agricultural production, it was also noted by several scholars that the practice is denying peasants access to strategic resources in many local communities in Africa.
Sino-African Foreign Direct Investment in Land
Authors: Ola-David Oluyomi
Published: December 2014

This chapter examines the political economy of Sino-African land acquisition with emphasis on land use for agriculture. Set within an institutions framework, it articulates a discourse on the motivation of Chinese cooperation with Africa. On China's role in Africa, the chapter identifies pessimistic views that focus on the potential imperialist character of China in African development as well as optimistic views that posit that African states have a crucial role to play in being architects of their own development, by setting institutions in place to maximize gains from Chinese development cooperation. From an historical perspective, large-scale land acquisition involves dispossession of land capital, legal aspects of property rights—which have gendered perspectives—and information asymmetry, all of which are recognized challenges to foreign investment in Africa. The chapter amplifies the silent reality that other emerging economies such as India and Brazil can influence agrarian transformation of Africa.
Land Acquisition and the Semantic Context of Land within the Normative Construction of “Modern Development”
Authors: Castañeda Renny Rueda
Published: December 2014

This chapter analyzes how, historically, normative interventions on the idea of “development” at the Bretton Woods Institutions have defined a theoretical bias from which land and land acquisition have been represented. On the one hand, the chapter proposes a framework from which representations of land, land acquisition, and land ownership can be contextualized within scholarly literature on the concept of development. The second part of the chapter carries out an empirical case study on linguistic analysis to highlight how increasing levels of land concentration go hand in hand with normative interventions built at the top of the executive bodies of an international architecture. The chapter reveals that rather than a coincidence, policies and recommendations on large-scale land acquisition have made part of a highly institutionalized and ideologically defined discourse that has evolved semantically within selected periods of the history of these institutions.
Foreign Direct Investment in Land Acquisitions in India
Authors: Sudan Falendra Kumar
Published: December 2014

There has been large-scale Foreign Direct Investment (FDI) in land in India for promotion of Special Economic Zones (SEZs). The key drivers of land acquisitions are food security, the bio-fuels boom, growing business opportunities, and policy reforms. Increased foreign land investment may increase economic growth and raise government revenues and create new livelihood opportunities through new capital, technology, know-how, infrastructure, and better market access. At the same time, foreign land acquisitions may result in local people losing access to the resources. Therefore, there is a need for wider public consultation involving all stakeholders to ensure improved livelihoods and food security. The creation of robust institutions and social and environmental impact assessments of FDI in land acquisitions are called for to promote inclusive growth through more job creation, infrastructure development, public revenues, environmental protection, and to protect local food security, particularly in times of food crisis. This chapter explores FDI in land acquisition in India.
Agents and Implications of Foreign Land Deals in East African Community
Authors: Osabuohien Evans S. , Gitau Ciliaka M. , Efobi Uchenna R. , Bruentrup Michael
Published: December 2014

Some of the factors that have been attributed to the global increase of Foreign Land Deals (FLDs) include the three Fs (food, fuel, and finance) crises, among others. However, most of the empirical evidence stems from the assessment of a broad set of countries. An analysis on the main determinants across host communities within a country presents specificity and closer reality. This chapter contributes by examining the community factors that could exert significant influence on determining whether or not a community receives FLDs in East African Community (EAC), focusing on Uganda. Uganda is an interesting case to investigate because the country is one of the destinations of FLDs in EAC, apart from Kenya and Tanzania. Taking it one step further, the chapter investigates the possible implications of FLDs on the host communities in terms of improvement (or deterioration) on selected community outcome variables: the quality and services relating to education, road, water, and health facilities.
Transformation from Subsistence to Commercial Agriculture in Nigeria
Authors: Obayelu Abiodun E.
Published: December 2014

Agriculture is in critical state in Nigeria with domestic food production being less than the growing population. The chapter analyzes the ongoing transformation of subsistence agriculture to commercial in Nigeria and the attendant effects of large-scale land acquisition on small-scale farmers. It uses both theoretical and empirical research designs with direct interviews of relevant stakeholders and case studies. It reviews past and present policies and programs aimed at transforming agriculture from subsistence to commercial in Nigeria. The results reveal that large-scale land acquisition and farming is not new in Nigeria. Acquisitions of land by foreigners has always been with the help and consent of government, unlike the case when it involves indigenous investors. Acquisitions have in most cases been characterized by conflicts between the landowners or tillers and investors. To transition successfully from subsistence to commercial agriculture, there is a need for strong collective actions between the depraved land owners, government, and investors.
Connecting Theory to Practice
Authors: Sedivy-Benton Amy L. , O'Kelly Mary K.
Published: December 2014

With higher education becoming more dynamic and institutions providing multiple venues for students to obtain advanced degrees, graduate programs are under increasing pressure to make explicit efforts to provide students with meaningful, practical application of research methods in order to prepare them to be successful researchers. Students must emerge from these programs with the knowledge, skills, and abilities to partake in research on their own. Yet, the current trend seems to be that students enter these programs lacking the basic skills needed to ensure success. They exhibit minimal self-efficacy and insufficient readiness to connect their coursework to application in their chosen profession. This chapter provides an overview of the skills and issues of graduate students and a discussion of how those issues affect student success in conducting independent research. The chapter concludes with recommendations for addressing those issues and an exploration of future trends.
Dancing with the Data
Authors: Lawrence Randee Lipson
Published: December 2014

Arts-based research is a dynamic approach to conducting qualitative research that expands on how knowledge is produced and communicated, reaching both academic and nonacademic audiences. Arts-based research is described as a political process that creates empathy, raises consciousness, and disrupts complacency. It touches the souls of the reading, viewing, or listening audience, often inspiring social activism. Several ways to use art in research are discussed, and examples are provided, including fiction as research data and expression, performance inquiry, textile art, poetry, and photography. The potential for arts-based research in graduate student research is also discussed. Arts-based research empowers both the research participants and the research audience as collaborative knowledge makers.
Research Methodologies for Multitasking Studies
Authors: Lin Lin , Cranton Patricia , Lee Jennifer
Published: December 2014

The research on multitasking is scattered across disciplines, and the definitions of multitasking vary according to the discipline. As a result, the research is not coherent nor consistent in the approaches taken to understanding this phenomenon. In this chapter, the authors review studies on multitasking in different disciplines with a focus on the research methodologies used. The three main research paradigms (empirical-analytical, interpretive, and critical) are used as a framework to understand the nature of the research. The strengths and weaknesses of the research in each of the paradigms are examined, and suggestions are made for utilizing different research methodologies to bring clarity to the research in this field. Such an endeavour will help to build interdisciplinary and multidisciplinary research and help guide future research and theory building.
Demystifying the Delphi Method
Authors: Shelton Kaye , Creghan Kathleen Adair
Published: December 2014

The Delphi research method was specifically designed as a forecasting tool for the Rand Corporation in the 1950s. However, in the last several decades, Delphi research has been more frequently used for facilitating group communication for decision making and planning. Because of the Delphi Method's increased use, more information is needed for researchers to understand how to best utilize the method to precisely complete a Delphi study with rigor. This chapter explores the Delphi Method's origin, provides an explanation of the methodology, acknowledges the types and variations in Delphi studies, discusses the advantages and limitations, and provides clear, step-by-step guidelines for employing a successful research study.
Growth Models in the Age of School Reform and Accountability
Authors: Mulvenon Sean W. , Bowman Sandra G. , Berta Jill A.
Published: December 2014

The reauthorization of the Elementary and Secondary School Act (ESEA) in 2002, also called “No Child Left Behind,” mandated use of accountability systems to evaluate school and district performance. The accountability systems were initially required to use cross-sectional student level assessment results in the evaluation models when assigning performance labels to school systems. Growth models were approved for use in the evaluation models in 2006, but their implementation required development of policy, identification of appropriate methods, and guidelines for assigning labels of performance to schools. The purpose of this chapter is to review the development of educational policy, implementation, and challenges in the use of growth models in accountability systems.
Energy Consumption Analysis of Secure and Clustered Wireless Sensor Network
Authors: Pokharel Ashim , Nigussie Ethiopia
Published: December 2014

Due to limited energy resources, different design strategies have been proposed in order to achieve better energy efficiency in wireless sensor networks, and organizing sensor nodes into clusters and data aggregation are among such solutions. In this work, secure communication protocol is added to clustered wireless sensor network. Security is a very important requirement that keeps the overall system usable and reliable by protecting the information in the network from attackers. The proposed and implemented AES block cipher provides confidentiality to the communication between nodes and base station. The energy efficiency of LEACH clustered network and with added security is analyzed in detail. In LEACH clustering along with the implemented data aggregation technique 48% energy has been saved compared to not clustered and no aggregation network. The energy consumption overhead of the AES-based security is 9.14%. The implementation is done in Contiki and the simulation is carried out in Cooja emulator using sky motes.
OpenSPARC Processor Evaluation Using Virtex-5 FPGA and High Performance Embedded Computing (HPEC) Benchmark Suite
Authors: Mhaidat Khaldoon Moosa , Baset Ahmad , Al-Khaleel Osama
Published: December 2014

OpenSPARC is the only 64-bit Chip Multi-Threaded (CMT) processor that has ever been made open-source and non-proprietary. In this paper, the authors present an FPGA-based embedded system and methodology for prototyping and validating the OpenSPARC processor. They also present synthesis and performance evaluation results for OpenSPARC on a Virtex-5 FPGA platform. Light version of OpenSolaris was successfully booted on the platform, and the High Performance Embedded Computing (HPEC) benchmark suite was used to evaluate the performance. Xilinx ISE suite was used for synthesis, implementation, and chip programming. The down-scaled FPGA implementation of the processor runs at 81.3 MHz. The whole processor would require about 176453 Virtex-5 logic slices. To the best of their knowledge, they are the first researchers to report detailed FPGA synthesis results for OpenSPARC and evaluate its performance on FPGA using the HPEC benchmarks. Other researchers may find these results useful when comparing with other processors or studying the impact of a certain design change or addition on performance and cost.
Hepatitis B vaccine uptake assessment in India
Authors: Bairwa Mohan
Published: December 2014

Not available.
Scientific contributions in the field of transport and supply chain management
Authors: Kruger Stephen , Ittmann Hans W.
Published: December 2014

The Department of Transport and Supply Chain Management at the University of Johannesburg proudly presents to you volume 8, 2014, of the Journal of Transport and Supply Chain Management (JTSCM), an accredited publication which is unique to South Africa.
Representation Theory and Analysis of Reductive Groups: Spherical Spaces and Hecke Algebras
Authors: Krötz Bernhard , Opdam Eric M. , Schlichtkrull Henrik , Trapa Peter
Published: December 2014

The workshop gave an overview of current research in the representation theory and analysis of reductive Lie groups and its relation to spherical varieties and Hecke algebras. The participants and the speakers represented an international blend of senior researchers and young scientists at the start of their career. Some particular topics covered in the 30 talks related to structure theory of spherical varieties, p-adic symmetric spaces, symmetry breaking operators, automorphic forms, and local Langlands correspondence.
Dirichlet Series and Function Theory in Polydiscs
Authors: Defant Andreas , Maestre Manuel , Saksman Eero , Seip Kristian
Published: December 2014

The interaction between Dirichlet series and function theory in polydiscs dates back to a fundamental insight of Harald Bohr and the subsequent groundbreaking work on multilinear forms and polarization by Bohnenblust and Hille. Since around 1997, there has been a revival of interest in the research area opened up by these early contributions. The workshop reflected the status of the field and led to fruitful discussions on problems of current interest and future research directions.
Mini-Workshop: Kähler Groups
Authors: Kotschick Dieter , Toledo Domingo
Published: December 2014

We reviewed recent advances in the study of fundamental groups of compact Kähler manifolds, involving an interesting mix of complex geometry, harmonic maps and non-Abelian Hodge theory, and geometric group theory. There were also extensive discussions of open problems in the area.
Mini-Workshop: Batalin-Vilkovisky Algebras, Operads, and Hopf Algebroids
Authors: Dotsenko Vladimir , Krähmer Ulrich
Published: December 2014

This workshop brought together 17 researchers whose work involves Batalin–Vilkovisky algebras, operads, and related structures such as Gerstenhaber algebras and cyclic homology. It featured introductory lectures on some relevant topics followed by talks about recent research results.
Estudo das práticas de gestão do conhecimento no Instituto Federal de Educação, Ciência e Tecnologia do Maranhão
Authors: Lima Nilzete Melo , Ziviani Fabricio , Reis Roberts Vinicius de Melo
Published: December 2014

O presente estudo tem por objetivo analisar as práticas de gestão do conhecimento adotadas no Instituto Federal de Educação, Ciência e Tecnologia do Maranhão – IFMA, órgão da administração indireta do Poder Público. Trata-se de uma pesquisa do tipo descritiva, utilizando-se o método quantitativo e como estratégia de pesquisa o estudo de caso. O instrumento utilizado para a coleta de dados foi o questionário que adotou o modelo de gestão do conhecimento proposto por Terra (2005). Os resultados obtidos possibilitaram verificar que as práticas de gestão do conhecimento no IFMA ainda se constituem um processo incipiente. São práticas isoladas associadas à gestão do conhecimento; apenas começam a ser discutidas com maior efetividade no momento atual. O estudo aponta que é condição fundamental para implantação do processo de Gestão do Conhecimento na administração pública o comprometimento da alta administração, o foco para uma política de desenvolvimento de recursos humanos, maior transparência, uso e compartilhamento de tecnologia de informação e comunicação e principalmente um olhar dirigido ao cidadão/cliente/consumidor/parceiro. Esse comprometimento deve repercutir no sentido de unir esforços a fim de incentivar as melhores práticas de gestão do conhecimento na administração pública.
Development of a 10-year (2001–2010) 0.1° data set of land-surface energy balance for mainland China
Authors: Chen X. , Su Z. , Ma Y. , Liu S. , Yu Q. , Xu Z.
Published: December 2014

Abstract. In the absence of high-resolution estimates of the components of surface energy balance for China, we developed an algorithm based on the surface energy balance system (SEBS) to generate a data set of land-surface energy and water fluxes on a monthly timescale from 2001 to 2010 at a 0.1 × 0.1° spatial resolution by using multi-satellite and meteorological forcing data. A remote-sensing-based method was developed to estimate canopy height, which was used to calculate roughness length and flux dynamics. The land-surface flux data set was validated against "ground-truth" observations from 11 flux tower stations in China. The estimated fluxes correlate well with the stations' measurements for different vegetation types and climatic conditions (average bias = 11.2 Wm−2, RMSE = 22.7 Wm−2). The quality of the data product was also assessed against the GLDAS data set. The results show that our method is efficient for producing a high-resolution data set of surface energy flux for the Chinese landmass from satellite data. The validation results demonstrate that more accurate downward long-wave radiation data sets are needed to be able to estimate turbulent fluxes and evapotranspiration accurately when using the surface energy balance model. Trend analysis of land-surface radiation and energy exchange fluxes revealed that the Tibetan Plateau has undergone relatively stronger climatic change than other parts of China during the last 10 years. The capability of the data set to provide spatial and temporal information on water-cycle and land–atmosphere interactions for the Chinese landmass is examined. The product is free to download for studies of the water cycle and environmental change in China.
Methane and carbon dioxide fluxes and their regional scalability for the European Arctic wetlands during the MAMM project in summer 2012
Authors: O'Shea S. J. , Allen G. , Gallagher M. W. , Bower K. , Illingworth S. M. , Muller J. B. A. , Jones B. T. , Percival C. J. , Bauguitte S. J-B. , Cain M. , Warwick N. , Quiquet A. , Skiba U. , Drewer J. , Dinsmore K. , Nisbet E. G. , Lowry D. , Fisher R. E. , France J. L. , Aurela M. , Lohila A. , Hayman G. , George C. , Clark D. B. , Manning A. J. , Friend A. D. , Pyle J.
Published: December 2014

Abstract. Airborne and ground-based measurements of methane (CH4), carbon dioxide (CO2) and boundary layer thermodynamics were recorded over the Fennoscandian landscape (67–69.5° N, 20–28° E) in July 2012 as part of the MAMM (Methane and other greenhouse gases in the Arctic: Measurements, process studies and Modelling) field campaign. Employing these airborne measurements and a simple boundary layer box model, net regional-scale (~ 100 km) fluxes were calculated to be 1.2 ± 0.5 mg CH4 h−1 m−2 and −350 ± 143 mg CO2 h−1 m−2. These airborne fluxes were found to be relatively consistent with seasonally averaged surface chamber (1.3 ± 1.0 mg CH4 h−1 m−2) and eddy covariance (1.3 ± 0.3 mg CH4 h−1 m−2 and −309 ± 306 mg CO2 h−1 m−2) flux measurements in the local area. The internal consistency of the aircraft-derived fluxes across a wide swath of Fennoscandia coupled with an excellent statistical comparison with local seasonally averaged ground-based measurements demonstrates the potential scalability of such localised measurements to regional-scale representativeness. Comparisons were also made to longer-term regional CH4 climatologies from the JULES (Joint UK Land Environment Simulator) and HYBRID8 land surface models within the area of the MAMM campaign. The average hourly emission flux output for the summer period (July–August) for the year 2012 was 0.084 mg CH4 h−1 m−2 (minimum 0.0 and maximum 0.21 mg CH4 h−1 m−2) for the JULES model and 0.088 mg CH4 h−1 m−2 (minimum 0.0008 and maximum 1.53 mg CH4 h−1 m−2) for HYBRID8. Based on these observations both models were found to significantly underestimate the CH4 emission flux in this region, which was linked to the under-prediction of the wetland extents generated by the models.
Ground-level ozone in four Chinese cities: precursors, regional transport and heterogeneous processes
Authors: Xue L. K. , Wang T. , Gao J. , Ding A. J. , Zhou X. H. , Blake D. R. , Wang X. F. , Saunders S. M. , Fan S. J. , Zuo H. C. , Zhang Q. Z. , Wang W. X.
Published: December 2014

Abstract. We analyzed the measurements of ozone (O3) and its precursors made at rural/suburban sites downwind of four large Chinese cities – Beijing, Shanghai, Guangzhou and Lanzhou, to elucidate their pollution characteristics, regional transport, in situ production, and impacts of heterogeneous processes. The same measurement techniques and observation-based model were used to minimize uncertainties in comparison of the results due to difference in methodologies. All four cities suffered from serious O3 pollution but showed different precursor distributions. The model-calculated in situ O3 production rates were compared with the observed change rates to infer the relative contributions of on-site photochemistry and transport. At the rural site downwind of Beijing, export of the well-processed urban plumes contributed to the extremely high O3 levels (up to an hourly value of 286 ppbv), while the O3 pollution observed at suburban sites of Shanghai, Guangzhou and Lanzhou was dominated by intense in situ production. The O3 production was in a volatile organic compound (VOC)-limited regime in both Shanghai and Guangzhou, and a NOx-limited regime in Lanzhou. The key VOC precursors are aromatics and alkenes in Shanghai, and aromatics in Guangzhou. The potential impacts on O3 production of several heterogeneous processes, namely, hydrolysis of dinitrogen pentoxide (N2O5), uptake of hydro peroxy radical (HO2) on particles and surface reactions of NO2 forming nitrous acid (HONO), were assessed. The analyses indicate the varying and considerable impacts of these processes in different areas of China depending on the atmospheric abundances of aerosol and NOx, and suggest the urgent need to better understand these processes and represent them in photochemical models.
Atmospheric aerosol characterization with a ground-based SPEX spectropolarimetric instrument
Authors: van Harten G. , de Boer J. , Rietjens J. H. H. , Di Noia A. , Snik F. , Volten H. , Smit J. M. , Hasekamp O. P. , Henzing J. S. , Keller C. U.
Published: December 2014

Abstract. Characterization of atmospheric aerosols is important for understanding their impact on health and climate. A wealth of aerosol parameters can be retrieved from multi-angle, multi-wavelength radiance and polarization measurements of the clear sky. We developed a ground-based SPEX instrument (groundSPEX) for accurate spectropolarimetry, based on the passive, robust, athermal, and snapshot spectral polarization modulation technique, and is hence ideal for field deployment. It samples the scattering phase function in the principal plane in an automated fashion, using a motorized pan/tilt unit and automatic exposure time detection. Extensive radiometric and polarimetric calibrations were performed, yielding values for both random noise and systematic uncertainties. The absolute polarimetric accuracy at low degrees of polarization is established to be ~5 × 10−3. About 70 measurement sequences have been performed throughout four clear-sky days at Cabauw, the Netherlands. Several aerosol parameters were retrieved: aerosol optical thickness, effective radius, and complex refractive index for fine and coarse mode. The results are in good agreement with the colocated AERONET products, with a correlation coefficient of ρ = 0.932 for the total aerosol optical thickness at 550 nm.
Scientific impact of MODIS C5 calibration degradation and C6+ improvements
Authors: Lyapustin A. , Wang Y. , Xiong X. , Meister G. , Platnick S. , Levy R. , Franz B. , Korkin S. , Hilker T. , Tucker J. , Hall F. , Sellers P. , Wu A. , Angal A.
Published: December 2014

Abstract. The Collection 6 (C6) MODIS (Moderate Resolution Imaging Spectroradiometer) land and atmosphere data sets are scheduled for release in 2014. C6 contains significant revisions of the calibration approach to account for sensor aging. This analysis documents the presence of systematic temporal trends in the visible and near-infrared (500 m) bands of the Collection 5 (C5) MODIS Terra and, to lesser extent, in MODIS Aqua geophysical data sets. Sensor degradation is largest in the blue band (B3) of the MODIS sensor on Terra and decreases with wavelength. Calibration degradation causes negative global trends in multiple MODIS C5 products including the dark target algorithm's aerosol optical depth over land and Ångström exponent over the ocean, global liquid water and ice cloud optical thickness, as well as surface reflectance and vegetation indices, including the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). As the C5 production will be maintained for another year in parallel with C6, one objective of this paper is to raise awareness of the calibration-related trends for the broad MODIS user community. The new C6 calibration approach removes major calibrations trends in the Level 1B (L1B) data. This paper also introduces an enhanced C6+ calibration of the MODIS data set which includes an additional polarization correction (PC) to compensate for the increased polarization sensitivity of MODIS Terra since about 2007, as well as detrending and Terra–Aqua cross-calibration over quasi-stable desert calibration sites. The PC algorithm, developed by the MODIS ocean biology processing group (OBPG), removes residual scan angle, mirror side and seasonal biases from aerosol and surface reflectance (SR) records along with spectral distortions of SR. Using the multiangle implementation of atmospheric correction (MAIAC) algorithm over deserts, we have also developed a detrending and cross-calibration method which removes residual decadal trends on the order of several tenths of 1% of the top-of-atmosphere (TOA) reflectance in the visible and near-infrared MODIS bands B1–B4, and provides a good consistency between the two MODIS sensors. MAIAC analysis over the southern USA shows that the C6+ approach removed an additional negative decadal trend of Terra ΔNDVI ~ 0.01 as compared to Aqua data. This change is particularly important for analysis of vegetation dynamics and trends in the tropics, e.g., Amazon rainforest, where the morning orbit of Terra provides considerably more cloud-free observations compared to the afternoon Aqua measurements.
Towards IASI-New Generation (IASI-NG): impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables
Authors: Crevoisier C. , Clerbaux C. , Guidard V. , Phulpin T. , Armante R. , Barret B. , Camy-Peyret C. , Chaboureau J.-P. , Coheur P.-F. , Crépeau L. , Dufour G. , Labonnote L. , Lavanant L. , Hadji-Lazaro J. , Herbin H. , Jacquinet-Husson N. , Payan S. , Péquignot E. , Pierangelo C. , Sellitto P. , Stubenrauch C.
Published: December 2014

Abstract. Besides their strong contribution to weather forecast improvement through data assimilation, thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring atmospheric composition changes. The Infrared Atmospheric Sounding Interferometer (IASI) instrument developed by the French space agency (CNES) and launched by EUMETSAT onboard the Metop satellite series is providing essential inputs for weather forecasting and pollution/climate monitoring owing to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance. EUMETSAT is currently preparing the next polar-orbiting program (EPS-SG) with the Metop-SG satellite series that should be launched around 2020. In this framework, CNES is studying the concept of a new instrument, the IASI-New Generation (IASI-NG), characterized by an improvement of both spectral and radiometric characteristics as compared to IASI, with three objectives: (i) continuity of the IASI/Metop series; (ii) improvement of vertical resolution; and (iii) improvement of the accuracy and detection threshold for atmospheric and surface components. In this paper, we show that an improvement of spectral resolution and radiometric noise fulfil these objectives by leading to (i) a better vertical coverage in the lower part of the troposphere, thanks to the increase in spectral resolution; and (ii) an increase in the accuracy of the retrieval of several thermodynamic, climate and chemistry variables, thanks to the improved signal-to-noise ratio as well as less interference between the signatures of the absorbing species in the measured radiances. The detection limit of several atmospheric species is also improved. We conclude that IASI-NG has the potential to strongly benefit the numerical weather prediction, chemistry and climate communities now connected through the European GMES/Copernicus initiative.
Application of GC/Time-of-Flight-MS for halocarbon trace gas analysis and comparison with GC/Quadrupole-MS
Authors: Hoker J. , Obersteiner F. , Bönisch H. , Engel A.
Published: December 2014

Abstract. We present the application of Time-of-Flight Mass Spectrometry (TOF MS) for the analysis of halocarbons in the atmosphere, after cryogenic sample preconcentration and gas chromatographic separation. For the described field of application, the Quadrupole Mass Spectrometer (QP MS) is the state-of-the-art detector. This work aims at comparing two commercially available instruments, a QP MS and a TOF MS with respect to mass resolution, mass accuracy, sensitivity, measurement precision and detector linearity. Both mass spectrometers are operated on the same gas chromatographic system by splitting the column effluent to both detectors. The QP MS had to be operated in optimised Single Ion Monitoring (SIM) mode to achieve a sensitivity which could compete with the TOF MS. The TOF MS provided full mass range information in any acquired mass spectrum without losing sensitivity. Whilst the QP MS showed the performance already achieved in earlier tests, the sensitivity of the TOF MS was on average higher than that of the QP MS in the "operational" SIM mode by a factor of up to 3 reaching detection limits of less than 0.2 pg. Measurement precision determined for the whole analytical system was up to 0.2% depending on substance and sampled volume. The TOF MS instrument used for this study displayed significant non-linearities of up to 10% for two third of all analysed substances.
Export fluxes in a naturally fertilized area of the Southern Ocean, the Kerguelen Plateau: ecological vectors of carbon and biogenic silica to depth (Part 2)
Authors: Rembauville M. , Blain S. , Armand L. , Quéguiner B. , Salter I.
Published: December 2014

Abstract. The chemical (particulate organic carbon and nitrogen, biogenic silica) and biological (diatoms and faecal pellets) composition of the material exported to a moored sediment trap located under the winter mixed layer of the naturally-fertilized Kerguelen Plateau in the Southern Ocean was studied over an annual cycle. Despite iron availability in spring, the annual particulate organic carbon (POC) export (98.2 mmol m−2) at 289 m was low but annual biogenic silica export was significant (114 mmol m−2). This feature was related to the abundance of empty diatom frustules and the ratio of full : empty cell exerted a first order control in BSi : POC export stoichiometry of biological pump. Chaetoceros Hyalochaete spp. and Thalassiosira antarctica resting spores were found to be responsible for more than 60% of the annual POC that occurred during two very short export events (<14 days in spring-summer) representing the majority of captured export. Low diatom fluxes were observed over the remainder of the year. Faecal pellet contribution to annual carbon flux was low (34%) and reached it's seasonal maximum in autumn and winter (>80%). The seasonal progression of faecal pellet types revealed a clear transition from small spherical shapes (small copepods) in spring, larger cylindrical and ellipsoid shapes in summer (euphausiids and large copepods) and finally large tabular shapes (salps) in autumn and winter. We propose that in this High Biomass, Low Export (HBLE) environment, small, highly silicified, fast-sinking resting spores are able to bypass the high grazing pressure and efficient carbon transfer to higher trophic levels that are responsible for the low fluxes observed the during the remainder of the year. Our study also provides a statistical framework linking the ecological succession of diatom and zooplankton communities to the seasonality of carbon and silicon export within an iron-fertilized bloom region in the Southern Ocean.
Lunar periodicity in the shell flux of some planktonic foraminifera in the Gulf of Mexico
Authors: Jonkers L. , Reynolds C. E. , Richey J. , Hall I. R.
Published: December 2014

Abstract. Synchronised reproduction offers clear benefits to planktonic foraminifera – an important group of marine calcifiers – as it increases the chances of successful gamete fusion. Such synchrony requires tuning to an internal or external clock. Evidence exists for lunar reproductive cycles in some species, but its recognition in shell flux time series has proven difficult, raising questions about reproductive strategies. Using spectral analysis of a 6 year time series (mostly at weekly resolution) from the northern Gulf of Mexico we show that the shell flux of Globorotalia menardii, Globigerinella siphonifera, Orbulina universa, Globigerinoides sacculifer and in Globigerinoides ruber (both pink and white varieties) is characterised by lunar periodicity. The fluxes of Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerinella calida, Globorotalia crassaformis and Globigerinita glutinata do not show significant spectral power at the lunar frequency. If present, lunar periodicity is superimposed on longer term/seasonal changes in the shell fluxes, but accounts for a significant part of the variance in the fluxes. The amplitude of the lunar cycle increases roughly proportional with the magnitude of the flux, demonstrating that most of the population is indeed affected by lunar-phased synchronisation. Phasing of peak fluxes appears species-specific, with G. menardii, O. universa and G. sacculifer showing most peaks around the full moon and G. ruber one week later. Contrastingly, peaks G. siphonifera occur dominantly around new moon. Very limited literature exists on lunar phasing of foraminiferal export fluxes, but spatial differences in its presence may exist, corroborating the exogenous nature of lunar synchrony in planktonic foraminifera.
Modelling atmospheric dry deposition in urban areas using an urban canopy approach
Authors: Cherin N. , Roustan Y. , Musson-Genon L. , Seigneur C.
Published: December 2014

Abstract. Atmospheric dry deposition is typically modelled using an average roughness length, which depends on land use. This classical roughness-length approach cannot account for the spatial variability of dry deposition in complex settings such as urban areas. Urban canopy models have been developed to parametrise momentum and heat transfer. We extend this approach here to mass transfer and a new dry deposition model based on the urban canyon concept is presented. It uses a local mixing length parametrisation of turbulence within the canopy, and a description of the urban canopy via key parameters to provide spatially-distributed dry deposition fluxes. Three different flow regimes are distinguished in the urban canyon depending on the height-to-width ratio of built areas: isolated roughness flow, wake interference flow and skimming flow. Differences between the classical roughness-length model and the model developed here are investigated. Sensitivity to key parameters are discussed. This approach provides spatially-distributed dry deposition fluxes that depend on surfaces (streets, walls, roofs) and flow regimes (recirculation and ventilation) within the urban area.
Building a field- and model-based climatology of local water and energy cycles in the cultivated Sahel – annual budgets and seasonality
Authors: Velluet C. , Demarty J. , Cappelaere B. , Braud I. , Issoufou H. B.-A. , Boulain N. , Ramier D. , Mainassara I. , Charvet G. , Boucher M. , Chazarin J.-P. , Oï M. , Yahou H. , Maidaji B. , Arpin-Pont F. , Benarrosh N. , Mahamane A. , Nazoumou Y. , Favreau G. , Seghieri J.
Published: December 2014

Abstract. In the sub-Saharan Sahel, energy and water cycling at the land surface is pivotal for the regional climate, water resources and land productivity, yet it is still very poorly documented. As a step towards a comprehensive climatological description of surface fluxes in this area, this study provides estimates of long-term average annual budgets and seasonal cycles for two main land use types of the cultivated Sahelian belt: rainfed millet crop and fallow bush. These estimates build on the combination of a 7-year field data set from two typical plots in southwestern Niger with detailed physically based soil–plant–atmosphere modeling, yielding a continuous, comprehensive set of water and energy flux and storage variables over this multiyear period. In the present case in particular, blending field data with mechanistic modeling makes the best use of available data and knowledge for the construction of the multivariate time series. Rather than using the model only to gap-fill observations into a composite series, model–data integration is generalized homogeneously over time by generating the whole series with the entire data-constrained model simulation. Climatological averages of all water and energy variables, with associated sampling uncertainty, are derived at annual to sub-seasonal scales from the time series produced. Similarities and differences in the two ecosystem behaviors are highlighted. Mean annual evapotranspiration is found to represent ~82–85% of rainfall for both systems, but with different soil evaporation/plant transpiration partitioning and different seasonal distribution. The remainder consists entirely of runoff for the fallow, whereas drainage and runoff stand in a 40–60% proportion for the millet field. These results should provide a robust reference for the surface energy- and water-related studies needed in this region. Their significance and the benefits they gain from the innovative data–model integration approach are thoroughly discussed. The model developed in this context has the potential for reliable simulations outside the reported conditions, including changing climate and land cover.
Virtual laboratories: new opportunities for collaborative water science
Authors: Ceola S. , Arheimer B. , Blöschl G. , Baratti E. , Capell R. , Castellarin A. , Freer J. , Han D. , Hrachowitz M. , Hundecha Y. , Hutton C. , Lindström G. , Montanari A. , Nijzink R. , Parajka J. , Toth E. , Viglione A. , Wagener T.
Published: December 2014

Abstract. Reproducibility and repeatability of experiments are the fundamental prerequisites that allow researchers to validate results and share hydrological knowledge, experience and expertise in the light of global water management problems. Virtual laboratories offer new opportunities to enable these prerequisites since they allow experimenters to share data, tools and pre-defined experimental procedures (i.e. protocols). Here we present the outcomes of a first collaborative numerical experiment undertaken by five different international research groups in a virtual laboratory to address the key issues of reproducibility and repeatability. Moving from the definition of accurate and detailed experimental protocols, a rainfall-runoff model was independently applied to 15 European catchments by the research groups and model results were collectively examined through a web-based discussion. We found that a detailed modelling protocol was crucial to ensure the comparability and reproducibility of the proposed experiment across groups. Our results suggest that sharing comprehensive and precise protocols and running the experiments within a controlled environment (e.g. virtual laboratory) is as fundamental as sharing data and tools for ensuring experiment repeatability and reproducibility across the broad scientific community and thus advancing hydrology in a more coherent way.
Glacier topography and elevation changes derived from Pléiades sub-meter stereo images
Authors: Berthier E. , Vincent C. , Magnússon E. , Gunnlaugsson Á. Þ. , Pitte P. , Le Meur E. , Masiokas M. , Ruiz L. , Pálsson F. , Belart J. M. C. , Wagnon P.
Published: December 2014

Abstract. In response to climate change, most glaciers are losing mass and hence contribute to sea-level rise. Repeated and accurate mapping of their surface topography is required to estimate their mass balance and to extrapolate/calibrate sparse field glaciological measurements. In this study we evaluate the potential of sub-meter stereo imagery from the recently launched Pléiades satellites to derive digital elevation models (DEMs) of glaciers and their elevation changes. Our five evaluation sites, where nearly simultaneous field measurements were collected, are located in Iceland, the European Alps, the central Andes, Nepal and Antarctica. For Iceland, the Pléiades DEM is also compared to a lidar DEM. The vertical biases of the Pléiades DEMs are less than 1 m if ground control points (GCPs) are used, but reach up to 7 m without GCPs. Even without GCPs, vertical biases can be reduced to a few decimetres by horizontal and vertical co-registration of the DEMs to reference altimetric data on ice-free terrain. Around these biases, the vertical precision of the Pléiades DEMs is ±1 m and even ±0.5 m on the flat glacier tongues (1σ confidence level). Similar precision levels are obtained in the accumulation areas of glaciers and in Antarctica. We also demonstrate the high potential of Pléiades DEMs for measuring seasonal, annual and multi-annual elevation changes with an accuracy of 1 m or better if cloud-free images are available. The negative region-wide mass balances of glaciers in the Mont-Blanc area (−1.04 ± 0.23 m a−1 water equivalent, w.e.) are revealed by differencing Satellite pour l'Observation de la Terre 5 (SPOT 5) and Pléiades DEMs acquired in August 2003 and 2012, confirming the accelerated glacial wastage in the European Alps.