bluuebunny/crossref_metadata_2025 huggingface dataset:
An Adaptive Data Collection Algorithm Based on a Bayesian Compressed Sensing Framework
Authors: Liu Zhi , Zhang Mengmeng , Cui Jian
Published: May 2014

For Wireless Sensor Networks, energy efficiency is always a key consideration in system design. Compressed sensing is a new theory which has promising prospects in WSNs. However, how to construct a sparse projection matrix is a problem. In this paper, based on a Bayesian compressed sensing framework, a new adaptive algorithm which can integrate routing and data collection is proposed. By introducing new target node selection metrics, embedding the routing structure and maximizing the differential entropy for each collection round, an adaptive projection vector is constructed. Simulations show that compared to reference algorithms, the proposed algorithm can decrease computation complexity and improve energy efficiency.
Calorimetric Thermoelectric Gas Sensor for the Detection of Hydrogen, Methane and Mixed Gases
Authors: Park Nam-Hee , Akamatsu Takafumi , Itoh Toshio , Izu Noriya , Shin Woosuck
Published: May 2014

A novel miniaturized calorimeter-type sensor device with a dual-catalyst structure was fabricated by integrating different catalysts on the hot (Pd/θ-Al2O3) and cold (Pt/α-Al2O3) ends of the device. The device comprises a calorimeter with a thermoelectric gas sensor (calorimetric-TGS), combining catalytic combustion and thermoelectric technologies. Its response for a model fuel gas of hydrogen and methane was investigated with various combustor catalyst compositions. The calorimetric-TGS devices detected H2, CH4, and a mixture of the two with concentrations ranging between 200 and 2000 ppm at temperatures of 100–400 °C, in terms of the calorie content of the gases. It was necessary to reduce the much higher response voltage of the TGS to H2 compared to CH4. We enhanced the H2 combustion on the cold side so that the temperature differences and response voltages to H2 were reduced. The device response to H2 combustion was reduced by 50% by controlling the Pt concentration in the Pt/α-Al2O3 catalyst on the cold side to 3 wt%.
An Investigation on the Feasibility of Uncalibrated and Unconstrained Gaze Tracking for Human Assistive Applications by Using Head Pose Estimation
Authors: Cazzato Dario , Leo Marco , Distante Cosimo
Published: May 2014

This paper investigates the possibility of accurately detecting and tracking human gaze by using an unconstrained and noninvasive approach based on the head pose information extracted by an RGB-D device. The main advantages of the proposed solution are that it can operate in a totally unconstrained environment, it does not require any initial calibration and it can work in real-time. These features make it suitable for being used to assist human in everyday life (e.g., remote device control) or in specific actions (e.g., rehabilitation), and in general in all those applications where it is not possible to ask for user cooperation (e.g., when users with neurological impairments are involved). To evaluate gaze estimation accuracy, the proposed approach has been largely tested and results are then compared with the leading methods in the state of the art, which, in general, make use of strong constraints on the people movements, invasive/additional hardware and supervised pattern recognition modules. Experimental tests demonstrated that, in most cases, the errors in gaze estimation are comparable to the state of the art methods, although it works without additional constraints, calibration and supervised learning.
The Role of Economics and Democracy in Institutional Change for Sustainability
Authors: Söderbaum Peter
Published: May 2014

Institutional change for sustainable development does not happen by itself. Individuals and organizations function as actors to influence development processes. Reference is made to a “political economic person” (PEP) guided by her/his “ideological orientation” and “political economic organization” (PEO), guided by its “mission”. Leaving present unsustainable trends behind is a matter of politics and ideology and even power positions, where democracy plays a crucial role. The perspectives of influential (and other) actors are essential in facilitating (or hindering) change. I will discuss ideas of the role of science in society, mainstream neoclassical economics in relation to institutional economics in the spirit of K. William Kapp and Gunnar Myrdal as well as neo-liberalism as ideology (where neoclassical economics has contributed to strengthen the legitimacy of neo-liberalism). Various aspects of inertia and flexibility in institutional change processes, such as path dependence, are discussed. Emphasis is on the role of economics and how a strengthened democracy can open the door for a degree of pluralism.
Association of Human Mortality with Air Pollution of Hong Kong
Authors: Hoi Ka-In , Zhang Ding-Bian , Mok Kai-Meng , Yuen Ka-Veng
Published: May 2014

In this study, we attempted to investigate the general statistical association of air pollution with the cardiovascular and respiratory mortality of the elderly in Hong Kong. Based on six years of measurements including the major air pollutant concentrations (PM10, SO2, NO, NO2, O3, CO), ambient temperature, and mortality (respiratory, cardiovascular) between 2005 and 2010, correlation analysis was carried out in annual, monthly and weekly time scales. From an annual perspective, it was found that the air pollution species may pose a constant effect on the respiratory and the cardiovascular mortality during the studied period since the elderly mortality rates and the air pollution annual concentrations show obvious constant trends. From a monthly time scale, it was found that NO2 and CO have high positive cross correlation with the respiratory mortality of the following 1 to 2 months. In addition, PM10 and CO also have similar delayed influence on the cardiovascular mortality. Among these four pollutants, only CO was found to exhibit high statistical association in the weekly time scale and it is most related to the cardiovascular mortality of the week after next. Therefore, it was concluded that the effect of air pollution on the elderly mortality of Hong Kong should be cumulative. This study implies that the establishment of weekly or monthly air quality indices is necessary for health implications.
Economics of Managed Aquifer Recharge
Authors: Maliva Robert
Published: May 2014

Managed aquifer recharge (MAR) technologies can provide a variety of water resources management benefits by increasing the volume of stored water and improving water quality through natural aquifer treatment processes. Implementation of MAR is often hampered by the absence of a clear economic case for the investment to construct and operate the systems. Economic feasibility can be evaluated using cost benefit analysis (CBA), with the challenge of monetizing benefits. The value of water stored or treated by MAR systems can be evaluated by direct and indirect measures of willingness to pay including market price, alternative cost, value marginal product, damage cost avoided, and contingent value methods. CBAs need to incorporate potential risks and uncertainties, such as failure to meet performance objectives. MAR projects involving high value uses, such as potable supply, tend to be economically feasible provided that local hydrogeologic conditions are favorable. They need to have low construction and operational costs for lesser value uses, such as some irrigation. Such systems should therefore be financed by project beneficiaries, but dichotomies may exist between beneficiaries and payers. Hence, MAR projects in developing countries may be economically viable, but external support is often required because of limited local financial resources.
Simplified Flood Inundation Mapping Based On Flood Elevation-Discharge Rating Curves Using Satellite Images in Gauged Watersheds
Authors: Jung Younghun , Kim Dongkyun , Kim Dongwook , Kim Munmo , Lee Seung
Published: May 2014

This study suggests an approach to obtain flood extent boundaries using spatial analysis based on Landsat-5 Thematic Mapper imageries and the digital elevation model. The suggested approach firstly extracts the flood inundation areas using the ISODATA image-processing algorithm from four Landsat 5TM imageries. Then, the ground elevations at the intersections of the extracted flood extent boundaries and the specified river cross sections are read from the digital elevation to estimate the elevation-discharge relationship. Lastly, the flood extent is generated based on the estimated elevation-discharge relationship. The methodology was tested over two river reaches in Indiana, United States. The estimated elevation-discharge relationship showed a good match with the correlation coefficients varying between 0.82 and 0.99. In addition, self-validation was also performed for the estimated spatial extent of the flood by comparing it to the waterbody extracted from the Landsat images used to develop the elevation-discharge relationship. The result indicated that the match between the estimated and the extracted flood extents was better with higher flood magnitude. We expect that the suggested methodology will help under-developed and developing countries to obtain flood maps, which have difficulties getting flood maps through traditional approaches based on computer modeling.
Observations sur l'origine, la classification et l'écologie des espèces fourragères
Authors: Hédin Louis
Published: May 2014

Dans la première partie de cette étude, l'auteur fait ressortir le fait qu'il existe un complexe herbage-animal qui explique le rapport entre la composition de la végétation et les animaux qui paissent les herbages. On trouve généralement des plantes servant à l'alimentation animale dans les régions où de grands troupeaux d'animaux sauvages paissaient avant les débuts de l'agriculture. C'est souvent là où le climat est uniforme toute l'année que se rencontrent les plantes les plus intéressantes. Dans ces régions, il y a des espèces hygrophiles, tandis que dans les steppes ce sont des plantes à feuilles étroites et souvent épineuses que l'on voit. Il est intéressant d'étudier les espèces fourragères dans les régions montagneuses parce que des chèvres et des moutons sauvages y vivaient autrefois. Pour nourrir les animaux les premiers agriculteurs semèrent généralement dans les terres en friche des céréales que les hommes consomment (Farrago). C'est dans les forêts que les animaux paissaient d'ordinaire de sorte que de nombreuses régions ont perdue une grande partie de leur couvert forestier. En Europe occidentale, on a commencé à sélectionner les plantes fourragères (excepté la luzerne) au début de la révolution agricole qui s'est produite en même temps que les transformations économiques et sociales dès les premiers années du XVIe s. L'auteur passe en revue les étapes de cette sélection qui est devenue de plus en plus rationelle. Sa classification des plantes fourragères tient compte de la genèse de cette sélection. Nombre de plantes fourragères ont été cultivées autrefois pour l'alimentation humaine et beaucoup de « mauvaises herbes » sont devenues des plantes fourragères. La dernière partie de l'étude contient les caractères écologiques des espèces fourragères : hygrophiles, nitrophiles et sciaphiles. On trouve des espèces hâtives annuelles dans les régions arides où elles peuvent croître pendant la courte saison des pluies. L'auteur conclut en indiquant les principes à observer pour aborder les problèmes de l'introduction de plantes fourragères dans des régions qui manquent d'espèces utiles. Il est souhaitable d'organiser un cours d'enseignement pour l'étude des problèmes de l'adaptation des plantes à leur milieu.
Integrated Destination Competitiveness Model: Testing Its Validity and Data Accessibility
Authors: Dwyer Larry , Cvelbar Ljubica Knežević , Mihalič Tanja , Koman Matjaž
Published: May 2014

Destination competitiveness has attracted much attention from researchers over the past two decades. The Integrated Destination Competitiveness Model has been used to explore destination competitiveness in many contexts including Australia, Korea, Slovenia, and Serbia. Given its popularity
with tourism researchers and its application to destination competitiveness studies world-wide, it is appropriate to undertake a rigorous test of the destination competitiveness attributes identified in this model, their validity and indicator accessibility to researchers and practitioners.
Testing the 83 destination competitiveness attributes of this major model can inform researchers about the appropriateness of the model structure, the validity of the groupings of destination competitiveness attributes, and the relevance of different indicators to destination attributes. The
data used for testing are comprehensive, covering 139 countries worldwide in the period 2007 to 2011. The testing process confirms the value of the Integrated Model in understanding a destination's competitiveness indicators, the gains from which will be more informed policy making regarding
the type of tourism development most likely to enhance resident quality of economic and social life.
Travel Decision Flexibility
Authors: Park Sangwon , Fesenmaier Daniel R.
Published: May 2014

This study builds on previous research examining the concept of travel decision flexibility based on theories related to adaptive decision making, which argue that travelers perceive different levels of flexibility depending on the trip-related decision. The results of this study indicate
that there are two distinctive types of decision flexibility, which are related to the timing and components of the trip: pretrip and en route flexibility. The constructs are examined for their external validity using several travel situational factors, including number of alternatives, prior
knowledge, length of stay, planning horizon, and types of travel groups. These findings are important in that they help us to understand better the underlying structure and characteristics of travel decisions and, in turn, help us identify potential ways to design more effective information
delivery systems using information technology.
Including Pets When Undertaking Tourism Activities: Incorporating Pet Attachment into the TPB Model
Authors: Peng Norman , Chen Annie , Hung Kuang-Peng
Published: May 2014

As modern individuals place increasing value on tourism and have an increasing attachment to their pets, it is important for scholars, practitioners, and other relevant parties to determine whether pet owners will plan to have their pets accompany them when travelling for tourism purposes.
Based on an analysis of 458 dog owners, this study's results provide support for the application of the TPB model in the context of this subject. The findings of this study on the influence of pet attachment on owners' attitudes and intentions shed new light on the existing literature and
contribute to tourism literature and practices.
Biocalcite, a multifunctional inorganic polymer: Building block for calcareous sponge spicules and bioseed for the synthesis of calcium phosphate-based bone
Authors: Wang Xiaohong , Schröder Heinz C , Müller Werner E G
Published: May 2014

Calcium carbonate is the material that builds up the spicules of the calcareous sponges. Recent results revealed that the calcium carbonate/biocalcite-based spicular skeleton of these animals is formed through an enzymatic mechanism, such as the skeleton of the siliceous sponges, evolutionarily the oldest animals that consist of biosilica. The enzyme that mediates the calcium carbonate deposition has been identified as a carbonic anhydrase (CA) and has been cloned from the calcareous sponge species Sycon raphanus. Calcium carbonate deposits are also found in vertebrate bones besides the main constituent, calcium phosphate/hydroxyapatite (HA). Evidence has been presented that during the initial phase of HA synthesis poorly crystalline carbonated apatite is deposited. Recent data summarized here indicate that during early bone formation calcium carbonate deposits enzymatically formed by CA, act as potential bioseeds for the precipitation of calcium phosphate mineral onto bone-forming osteoblasts. Two different calcium carbonate phases have been found during CA-driven enzymatic calcium carbonate deposition in in vitro assays: calcite crystals and round-shaped vaterite deposits. The CA provides a new target of potential anabolic agents for treatment of bone diseases; a first CA activator stimulating the CA-driven calcium carbonate deposition has been identified. In addition, the CA-driven calcium carbonate crystal formation can be frozen at the vaterite state in the presence of silintaphin-2, an aspartic acid/glutamic acid-rich sponge-specific protein. The discovery that calcium carbonate crystals act as bioseeds in human bone formation may allow the development of novel biomimetic scaffolds for bone tissue engineering. Na-alginate hydrogels, enriched with biosilica, have recently been demonstrated as a suitable matrix to embed bone forming cells for rapid prototyping bioprinting/3D cell printing applications.
Performance of hybrid cement composite elements under drop-weight impact load
Authors: Nguyen V. D. , Río O. , Sánchez-Gálvez V.
Published: May 2014

The performance, under drop-weight impact load, of hybrid cement composite (HCC) elements, consisting of a top layer of plain concrete (PC) and a bottom layer of fibre reinforced concrete (FRC), in comparison with full-depth FRC and PC was studied. Apart from improving the tensile capacity of PC and saving fibre steel reinforcements of FRC, the results showed that HCC can effectively control the deformations and enhance the impact performance of the structural members as its outcomes were similar to that of a full-depth FRC. The analytical studies using Hughes empirical formulae (HEF) and yield line theory (YLT) adopted to investigate the practical use of HCC showed that they are applicable for design such HCC elements against impacts.
Internal Control Considerations for Information System Changes and Patches
Authors: Zanzig Jeffrey S. , Francia III Guillermo A. , Francia Xavier P.
Published: May 2014

The dependence of businesses on properly functioning information systems to allow organizational personnel and outside investors to make important decisions has never been more pronounced. Information systems are constantly evolving due to operational and security requirements. These changes to information systems involve a risk that they could occur in a way that results in improper processing of information and/or security issues. The purpose of this chapter is to consider related guidance provided in a Global Technology Audit Guide (GTAG) from The Institute of Internal Auditors in conjunction with current change and patch management literature in order to assist internal auditors and organizational personnel in better understanding a process that leads to efficient and effective information system changes. The authors describe how internal auditors and information technology professionals can work together with organization management to form a mature approach in addressing both major information system changes and patches.
Organizational Memory
Authors: Ramos Isabel , Oliveira e Sá Jorge
Published: May 2014

Nowadays, the major challenge to organizations managers is that they must make appropriate decisions in a turbulent environment while it is hard to recognize whether information is good or bad, because actions resulting from wrong decisions may place the organization at risk of survival. That is why organizations managers try to avoid making wrong decisions. In order to improve this, managers should use collective knowledge and experiences shared through Organizational Memory (OM) effectively to reduce the rate of unsuccessful decision making. In this sense, Business Intelligence (BI) tools allow managers to improve the effectiveness of decision making and problem solving. In the light of these motivations, the aim of this chapter is to comprehend the role of BI systems in supporting OM effectively in the real context of a crowdsourcing academic initiative called CrowdUM.
Motivation in Electronic Portfolio Usage for Higher Education Institutions
Authors: Mobarhan Rokhsareh , Majidi Mojib , Rahman Azizah Abdul
Published: May 2014

One of the important technologies which deliver more effective and efficient services to students, lecturers, administrators and universities is Electronic Portfolio. It's defined as a student collection of learning progress, accomplishments and reflections. Nowadays most of the universities have joined to use e-Portfolio, due to the advantages provided for their organizational success. Despite of their large investment in e-Portfolio, its utilization is not continued. A major challenge is “how to increase the continuous use of e-Portfolio.” Most of the literature has ignored the role of motivation in its continuance usage. Regarding these issues, the main goal of this chapter is to highlight the importance of motivation in e-portfolio context to sustain its utilization. By reviewing the literature, the self-determination theory (SDT) integrating with IS-Continuance model is proposed as the best solution for overcoming the current problems. Autonomy, competence and relatedness are supposed to have a significant influence on continuous use of e-Portfolio system.
How Social Media Tools are Used in Research
Authors: Mesquita Anabela , Correia Ana Ramalho , Vieira Diana Aguiar
Published: May 2014

Social media tools are being widely used. Every day we witness new tools appearing or new features being added to already existing tools. Their characteristics allow us to communicate and collaborate without time and space constraints. Moreover, they also help us in the development and creation of new content as well as in the sharing and publishing of it. Since they are so popular, can it be that researchers are also using them in the research workflow process? If they use them, what are the most commonly used tools and their reasons for use? These are some of the questions addressed in this chapter. The authors analyse responses given by a higher education institution to a questionnaire on the use of social media tools. These findings contribute to a greater understanding of the importance of these tools for research purposes.
Validation of Performance Indicators for Evaluation of Workplace Health Promotion
Authors: Ho Seung Hee , Chae Young Moon
Published: May 2014

Purpose.

To validate performance indicators for evaluating workplace health promotion (WHP) programs based on a logic model and to analyze the structural relationships between constructs.

Design.

The study design is cross-sectional.

Setting.

Design setting was small manufacturing companies implementing WHP programs provided by the Korea Industrial Health Association.

Subjects.

Seventeen occupational health experts completed a questionnaire to determine the content validity of indicators. In addition, 58 health care managers completed a questionnaire to determine reliability and construct validation. The response rate was 84.1%.

Measures.

Based on a logic model, 13 constructs of WHP programs were identified: WHP program input, four activities for workplace environment management, two activities for employee health care management, two outputs, and two short-term outcomes.

Analysis.

Interrater agreement index was used for testing the content validity of indicators. Confirmatory factor analysis was used to test for the reliabilities, and the convergent and discriminant validities. Structuring equation modeling was also used to analyze the relationships among constructs.

Results.

A total of 35 performance indicators from 11 constructs showed good reliability and validity. All relationships among WHP input, activities, outputs, and short-term outcomes were significant, except for the relationship between environment outputs and short-term outcome.

Conclusion.

These findings illustrate that the logic model and structuring equation modeling can be used to develop and validate performance indicators for planning and evaluation of the WHP program.
Development and Reliability Testing of a Fast-Food Restaurant Observation Form
Authors: Rimkus Leah , Ohri-Vachaspati Punam , Powell Lisa M. , Zenk Shannon N. , Quinn Christopher M. , Barker Dianne C. , Pugach Oksana , Resnick Elissa A. , Chaloupka Frank J.
Published: May 2014

Purpose.

To develop a reliable observational data collection instrument to measure characteristics of the fast-food restaurant environment likely to influence consumer behaviors, including product availability, pricing, and promotion.

Design.

The study used observational data collection.

Setting.

Restaurants were in the Chicago Metropolitan Statistical Area.

Subjects.

A total of 131 chain fast-food restaurant outlets were included.

Measures.

Interrater reliability was measured for product availability, pricing, and promotion measures on a fast-food restaurant observational data collection instrument.

Analysis.

Analysis was done with Cohen's κ coefficient and proportion of overall agreement for categorical variables and intraclass correlation coefficient (ICC) for continuous variables.

Results.

Interrater reliability, as measured by average κ coefficient, was .79 for menu characteristics, .84 for kids' menu characteristics, .92 for food availability and sizes, .85 for beverage availability and sizes, .78 for measures on the availability of nutrition information, .75 for characteristics of exterior advertisements, and .62 and .90 for exterior and interior characteristics measures, respectively. For continuous measures, average ICC was .88 for food pricing measures, .83 for beverage prices, and .65 for counts of exterior advertisements.

Conclusion.

Over 85% of measures demonstrated substantial or almost perfect agreement. Although some measures required revision or protocol clarification, results from this study suggest that the instrument may be used to reliably measure the fast-food restaurant environment.
Television Viewing Time and Measured Cardiorespiratory Fitness in Adult Women
Authors: Tucker Larry A. , Arens Peter J. , LeCheminant James D. , Bailey Bruce W.
Published: May 2014

Purpose.

This study assessed the relationship between television viewing time and measured cardiorespiratory fitness and the influence of various potential confounders.

Design.

Cross-sectional.

Setting.

Intermountain West.

Subjects.

The sample was composed of 302 nonsmoking women aged 40.2 ± 3.0 years, with ∼90% Caucasian and 82% married.

Measures.

TV viewing was assessed by using a questionnaire, and cardiorespiratory fitness was measured by using a graded, maximum treadmill test. Physical activity (PA) was evaluated by using accelerometers for 7 days, and body fat percentage (BF%) was measured by using the Bod Pod.

Analysis.

Analysis of variance and partial correlation.

Results.

VO2max of Frequent (≥3 h/d) TV viewers (32.6 ± 6.4 mL/kg/min) was significantly lower than that of both Moderate (1–2 h/d) (36.2 ± 7.2 mL/kg/min) or Infrequent (<1 h/d) (36.5 ± 6.5 mL/kg/min) viewers (F= 8.0, p = .0004). The Infrequent and Moderate groups did not differ in VO2max. Age, education, body mass index, and season of assessment had no influence on the relationship when controlled statistically. Adjusting for PA (F = 4.2, p = .0157) and BF% (F = 5.0, p = .0071) weakened the relationship by 59% and 58%, respectively, but the relationships remained significant. After controlling for both PA and BF% simultaneously (F = 2.9, p = .0572), the relationship was weakened by 81% and was only borderline significant.

Conclusion.

Female Frequent TV viewers have significantly lower cardiorespiratory fitness levels than Moderate or Infrequent viewers. This association appears to be largely a function of differences in levels of PA and BF%.
Surface gas pollutants in Lhasa, a highland city of Tibet: current levels and pollution implications
Authors: Ran L. , Lin W. L. , Deji Y. Z. , La B. , Tsering P. M. , Xu X. B. , Wang W.
Published: May 2014

Abstract. Through several years of development, the city of Lhasa has become one of the most populated and urbanized areas on the highest plateau in the world. In the process of urbanization, current and potential air quality issues have been gradually concerned. To investigate the current status of air pollution in Lhasa, various gas pollutants including NOx, CO, SO2 and O3 were continuously measured from June 2012 to May 2013 at an urban site (29.40° N, 91.08° E, 3650 m a.s.l.). The seasonal variations of primary gas pollutants exhibited a peak from November to January with a large variability. High concentrations of primary trace gases almost exclusively occurred under low wind speed and showed no distinct dependence on wind direction, implying local urban emissions to be predominant. A comparison of NO2, CO and SO2 concentrations in summer between 1998 and 2012 indicated a significant increase in emissions of these gas pollutants and a change in their intercorrelations, as a result of a substantial growth in the demand of energy consumption using fossil fuels instead of previously widely used biofuels. The pronounced diurnal double peaks of primary trace gases in all seasons suggested automobile exhaust to be a major emission source in Lhasa. The secondary gas pollutant O3 displayed an average diurnal cycle of a shallow flat peak for about 4–5 h in the afternoon and a minimum in the early morning. Nighttime O3 was sometimes completely consumed by the high level of NOx. Seasonally, the variations of O3 concentrations displayed a low valley in winter and a peak in spring. In autumn and winter, transport largely contributed to the observed O3 concentrations, given its dependence on wind speed and wind direction, while in spring and summer photochemistry played an important role. A more efficient buildup of O3 concentrations in the morning and a higher peak in the afternoon was found in summer 2012 than in 1998. An enhancement in O3 concentrations would be expected in the future and more attention should be given to O3 photochemistry in response to increasing precursor emissions in this area.
Tropical deep convective life cycle: Cb-anvil cloud microphysics from high altitude aircraft observations
Authors: Frey W. , Borrmann S. , Fierli F. , Weigel R. , Mitev V. , Matthey R. , Ravegnani F. , Sitnikov N. M. , Ulanovsky A. , Cairo F.
Published: May 2014

Abstract. The case study presented here focusses on the life cycle of clouds in a tropical deep convective system. During the SCOUT-O3 campaign from Darwin, Northern Australia, the Hector storm system has been probed by the Geophysica high altitude aircraft. Clouds were observed by in situ particle probes, a backscatter sonde, and a miniature lidar. Additionally, aerosol number concentrations have been measured. On 30 November 2005 a double flight took place and Hector was probed throughout its life cycle in its developing, mature, and dissipating stage. The two flights were four hours apart and focussed on the anvil region of Hector in altitudes between 10.5 km and 18.8 km (i.e. above 350 K potential temperature). Trajectory calculations and ozone measurements have been used to identify that the same cloud air masses have been probed in both flights. The size distributions derived from the measurements not only show a change with increasing altitude but also with the evolution of Hector. Clearly different aerosol to cloud particle ratios as well as varying ice crystal morphology have been found for the different development stages of Hector, indicating a change in freezing mechanisms. The development phase exhibits the smallest ice particles (up to 300 μm) with a rather uniform morphology. This is indicative for rapid glaciation during Hector's development. Sizes of ice crystals are largest in the mature stage (larger 1.6 mm) and even exceed those of some continental tropical deep convective clouds, also in their number concentrations. The backscatter properties and particle images show a change from frozen droplets in the developing phase to rimed and aggregated particles. The clouds in the dissipating stage have a large vertical extend (roughly 6 km) though optically thin and persist for at least 6 h. This poses a high potential for affecting the tropical tropopause layer background conditions regarding humidity, e.g. through facilitating subvisible cirrus formation, and with this the amount of water vapour that is transported into the stratosphere.
Atmospheric winter conditions 2007/08 over the Arctic Ocean based on NP-35 data and regional model simulations
Authors: Mielke M. , Zinoviev N. S. , Dethloff K. , Rinke A. , Kustov V. J. , Makshtas A. P. , Sokolov V. T. , Neuber R. , Maturilli M. , Klaus D. , Handorf D. , Graeser J.
Published: May 2014

Abstract. Atmospheric measurements on the drifting Arctic sea ice station "North Pole-35" crossing the Eastern part of the Arctic Ocean during winter 2007/2008 have been compared with regional atmospheric HIRHAM model simulations. The observed near-surface temperature, mean sea level pressure and the vertical temperature, wind and humidity profiles are satisfactorily reproduced by the model. The strongest temperature differences between observations and the simulations occur near the surface due to an overestimated vertical mixing of heat in the stable Arctic boundary layer (ABL). The observations show very strong temperature inversions near the surface, whereas the simulated inversions occur frequently between the surface and 415 m at too high levels. The simulations are not able to reproduce the observed inversion strength. The regional model underestimates the wind speeds and the sharp vertical wind gradients. The strength of internal atmospheric dynamics on the temporal development of atmospheric surface variables and vertical profiles of temperature, wind and relative humidity has been examined. Although the HIRHAM model systematically overestimates relative humidity and produces too high long-wave downward radiation during winter, two different atmospheric circulation states, which are connected to higher or lower pressure systems over the Eastern part of the Arctic Ocean, are simulated in agreement with the NP-35 observations. Sensitivity studies with reduced vertical mixing of heat in the stable ABL have been carried out. A slower increase in the stability functions with decreasing Richardson number under stable stratification has an impact on the horizontal and vertical atmospheric structure. Changes in synoptical cyclones on time scales from 1–3 days over the North Atlantic cyclone path are generated, which influences the atmospheric baroclinic and planetary waves on time scales up to 20 days over the Arctic Ocean basin. The use of increased vertical stability in the model simulation leads to diminished planetary-scale variability over the Arctic Ocean.
Measuring SO2 ship emissions with an ultraviolet imaging camera
Authors: Prata A. J.
Published: May 2014

Abstract. Over the last few years fast-sampling ultraviolet (UV) imaging cameras have been developed for use in measuring SO2 emissions from industrial sources (e.g. power plants; typical emission rates ~ 1–10 kg s−1) and natural sources (e.g. volcanoes; typical emission rates ~ 10–100 kg s−1). Generally, measurements have been made from sources rich in SO2 with high concentrations and emission rates. In this work, for the first time, a UV camera has been used to measure the much lower concentrations and emission rates of SO2 (typical emission rates ~ 0.01–0.1 kg s−1) in the plumes from moving and stationary ships. Some innovations and trade-offs have been made so that estimates of the emission rates and path concentrations can be retrieved in real time. Field experiments were conducted at Kongsfjord in Ny Ålesund, Svalbard, where SO2 emissions from cruise ships were made, and at the port of Rotterdam, Netherlands, measuring emissions from more than 10 different container and cargo ships. In all cases SO2 path concentrations could be estimated and emission rates determined by measuring ship plume speeds simultaneously using the camera, or by using surface wind speed data from an independent source. Accuracies were compromised in some cases because of the presence of particulates in some ship emissions and the restriction of single-filter UV imagery, a requirement for fast-sampling (> 10 Hz) from a single camera. Despite the ease of use and ability to determine SO2 emission rates from the UV camera system, the limitation in accuracy and precision suggest that the system may only be used under rather ideal circumstances and that currently the technology needs further development to serve as a method to monitor ship emissions for regulatory purposes. A dual-camera system or a single, dual-filter camera is required in order to properly correct for the effects of particulates in ship plumes.
Prototype of a drought monitoring and forecasting system for the Tuscany region
Authors: Magno R. , Angeli L. , Chiesi M. , Pasqui M.
Published: May 2014

Abstract. A system for drought monitoring and medium–long time forecasting in the Tuscany region (central Italy) is briefly introduced, which is based on ground and satellite data (1 km spatial resolution and 16-day temporal resolution). It is also shown how information about current conditions and future evolution of a drought event is periodically delivered on the LaMMA Consortium website, in collaboration with the Institute of Biometeorology (IBIMET-CNR).
Biogeophysical feedbacks enhance Arctic terrestrial carbon sink in regional Earth system dynamics
Authors: Zhang W. , Jansson C. , Miller P. A. , Smith B. , Samuelsson P.
Published: May 2014

Abstract. Continued warming of the Arctic will likely accelerate terrestrial carbon (C) cycling by increasing both uptake and release of C. There are still large uncertainties in modelling Arctic terrestrial ecosystems as a source or sink of C. Most modelling studies assessing or projecting the future fate of C exchange with the atmosphere are based an either stand-alone process-based models or coupled climate–C cycle general circulation models, in either case disregarding biogeophysical feedbacks of land surface changes to the atmosphere. To understand how biogeophysical feedbacks will impact on both climate and C budget over Arctic terrestrial ecosystems, we apply the regional Earth system model RCA-GUESS over the CORDEX-Arctic domain. The model is forced with lateral boundary conditions from an GCMs CMIP5 climate projection under the RCP 8.5 scenario. We perform two simulations with or without interactive vegetation dynamics respectively to assess the impacts of biogeophysical feedbacks. Both simulations indicate that Arctic terrestrial ecosystems will continue to sequester C with an increased uptake rate until 2060s–2070s, after which the C budget will return to a weak C sink as increased soil respiration and biomass burning outpaces increased net primary productivity. The additional C sinks arising from biogeophysical feedbacks are considerable, around 8.5 Gt C, accounting for 22% of the total C sinks, of which 83.5% are located in areas of Arctic tundra. Two opposing feedback mechanisms, mediated by albedo and evapotranspiration changes respectively, contribute to this response. Albedo feedback dominates over winter and spring season, amplifying the near-surface warming by up to 1.35 K in spring, while evapotranspiration feedback dominates over summer exerting the evaporative cooling by up to 0.81 K. Such feedbacks stimulate vegetation growth with an earlier onset of growing-season, leading to compositional changes in woody plants and vegetation redistribution.
Organomineral nanocomposite carbon burial during Oceanic Anoxic Event 2
Authors: Löhr S. C. , Kennedy M. J.
Published: May 2014

Abstract. Organic carbon (OC) enrichment in sediments deposited during Oceanic Anoxic Events (OAEs) is commonly attributed to elevated productivity and marine anoxia. We find that OC enrichment in the late Cenomanian aged OAE2 at Demerara Rise was controlled by co-occurrence of anoxic bottom-water, sufficient productivity to saturate available mineral surfaces and variable deposition of high surface area detrital smectite clay. Redox indicators show consistently oxygen-depleted conditions, while a strong correlation between OC concentration and sediment mineral surface area (R2=0.92) occurs across a range of TOC values from 9–33%. X-ray diffraction data indicates intercalation of OC in smectite interlayers while electron, synchrotron infrared and X-ray microscopy show an intimate association between clay minerals and OC, consistent with preservation of OC as organomineral nanocomposites and aggregates rather than discrete, μm-scale pelagic detritus. Since the consistent ratio between TOC and mineral surface area suggests that excess OC relative to surface area is lost, we propose that it is the varying supply of smectite that best explains variable organic enrichment against a backdrop of continuous anoxia, which is conducive to generally high TOC during OAE2 at Demerara Rise. Smectitic clays are unique in their ability to form stable organomineral nanocomposites and aggregates that preserve organic matter, and are common weathering products of continental volcanic deposits. An increased flux of smectite coinciding with high carbon burial is consistent with evidence for widespread volcanism during OAE2, so that organomineral carbon burial may represent a potential feedback to volcanic degassing of CO2.
North African vegetation-precipitation feedback in early and mid-Holocene climate simulations with CCSM3-DGVM
Authors: Rachmayani R. , Prange M. , Schulz M.
Published: May 2014

Abstract. The present study analyses the sign, strength and working mechanism of the vegetation-precipitation feedback over North Africa in middle (6 ka BP) and early Holocene (9 ka BP) simulations using the comprehensive coupled climate-vegetation model CCSM3-DGVM. The coupled model simulates enhanced summer rainfall and a northward migration of the West African monsoon trough along with an expansion of the vegetation cover for the early and middle Holocene compared to pre-industrial. It is shown that dynamic vegetation enhances the orbitally triggered summer precipitation anomaly by approximately 20% in the Sahara/Sahel region (10° N–25° N, 20° W–30° E) in both the early and mid-Holocene experiments compared to their fixed-vegetation counterparts. The primary vegetation-rainfall feedback identified here operates through surface latent heat flux anomalies by canopy evaporation and transpiration and their effect on the mid-tropospheric African Easterly Jet, whereas the effects of vegetation changes on surface albedo and local water recycling play a negligible role. Even though CCSM3-DGVM simulates a positive vegetation-precipitation feedback in the North African region, this feedback is not strong enough to produce multiple equilibrium climate-ecosystem states on a regional scale.
Development of a new semi-empirical parameterization for below-cloud scavenging of size-resolved aerosol particles by both rain and snow
Authors: Wang X. , Zhang L. , Moran M. D.
Published: May 2014

Abstract. A parameter called the scavenging coefficient Λ is widely used in aerosol chemical transport models (CTMs) to describe below-cloud scavenging of aerosol particles by rain and snow. However, uncertainties associated with available size-resolved theoretical formulations for Λ span one to two orders of magnitude for rain scavenging and nearly three orders of magnitude for snow scavenging. Two recent reviews of below-cloud scavenging of size-resolved particles recommended that the upper range of the available theoretical formulations for Λ should be used in CTMs based on uncertainty analyses and comparison with limited field experiments. Following this recommended approach, a new semi-empirical parameterization for size-resolved Λ has been developed for below-cloud scavenging of atmospheric aerosol particles by both rain (Λrain) and snow (Λsnow). The new parameterization is based on the 90th percentile of Λ values from an ensemble data set calculated using all possible "realizations" of available theoretical Λ formulas and covering a large range of aerosol particle sizes and precipitation intensities (R). For any aerosol particle size of diameter d, a strong linear relationship between the 90th-percentile log10 (Λ) and log10 (R), which is equivalent to a power-law relationship between Λ and R, is identified. The log-linear relationship, which is characterized by two parameters (slope and y intercept), is then further parameterized by fitting these two parameters as polynomial functions of aerosol size d. A comparison of the new parameterization with limited measurements in the literature in terms of the magnitude of Λ and the relative magnitudes of Λrain and Λsnow suggests that it is a reasonable approximation. Advantages of this new semi-empirical parameterization compared to traditional theoretical formulations for Λ include its applicability to below-cloud scavenging by both rain and snow over a wide range of particle sizes and precipitation intensities, ease of implementation in any CTM with a representation of size-distributed particulate matter, and a known representativeness, based on the consideration in its development, of all available theoretical formulations and field-derived estimates for Λ (d) and their associated uncertainties.
Grassland production under global change scenarios for New Zealand pastoral agriculture
Authors: Keller E. D. , Baisden W. T. , Timar L. , Mullan B. , Clark A.
Published: May 2014

Abstract. We adapt and integrate the Biome-BGC and Land Use in Rural New Zealand (LURNZ) models to simulate pastoral agriculture and to make land-use change, intensification and climate change scenario projections of New Zealand's pasture production at time slices centred on 2020, 2050 and 2100, with comparison to a present-day baseline. Biome-BGC model parameters are optimised for pasture production in both dairy and sheep/beef farm systems, representing a new application of the Biome-BGC model. Results show up to a 10% increase in New Zealand's national pasture production in 2020 under intensification and a 1–2% increase by 2050 from economic factors driving land-use change. Climate change scenarios using statistically downscaled global climate models (GCMs) from the IPCC Fourth Assessment Report (AR4) also show national increases of 1–2% in 2050, with significant regional variations. Projected out to 2100, however, these scenarios are more sensitive to the type of pasture system and the severity of warming: dairy systems show an increase in production of 4% under mild change but a decline of 1% under a more extreme case, whereas sheep/beef production declines in both cases by 3% and 13%, respectively. Our results suggest that high-fertility systems such as dairying could be more resilient under future change, with dairy production increasing or only slightly declining in all of our scenarios. These are the first national-scale estimates using a model to evaluate the joint effects of climate change, CO2 fertilisation and N-cycle feedbacks on New Zealand's unique pastoral production systems that dominate the nation's agriculture and economy. Model results emphasize that CO2 fertilisation and N cycle feedback effects are responsible for meaningful differences in agricultural systems. More broadly, we demonstrate that our model output enables analysis of Decoupled Land-Use Change Scenarios (DLUCS): the Biome-BGC data products at a national or regional level can be re-sampled quickly and cost-effectively for specific land-use change scenarios and future projections.