bluuebunny/crossref_metadata_2025 huggingface dataset:
A Development of Ocean Surface Wave and Wind Measurement From X-Band Marine Radar
Authors: Yang Y. J. , Park S. G. , Kwon S. H. , Park J. S.
Published: March 2016

The proposed method for ocean surface wave is carried out by a statistical analysis of the x-band marine radar image. In particular, by using the Fast Fourier Transform in 3-dimensional method and the linear dispersion relation derives a parameter of the ocean wave such as significant wave height and peak wave period.

For the ocean surface wind measurements using radar cross section, and the image superposition method is used. Signal to Noise Ratio is used to measure wave height and wind velocity.

Wave height, wave period, wind velocity, and wind direction were used for a long period of time, measuring the data from the IEODO ocean research station in Republic of Korea to the validation. In addition, compared with the measurement results of the light beacon in the radar image boundary and radar system located on the coast. The results were in good agreement with the quantitative analysis, the possibility of commercialization could be founded. Comparison data were obtained through the cooperation of the Republic of Korea Meteorological Administration and the National Oceanographic Research Institute.

It is possible to use the measurement of wind and wave radar mounted on ships and offshore plants. This system benefits the efficiency of the plant operation.
Electrohydraulic ICV Control System: A Novel Approach to Multizonal Control
Authors: Garcia Elias , Saldanha Savio
Published: March 2016

With the increasing number of laterals or extended horizontal-well depths, operators are seeking to maximize zonal control using intelligent completions. Electrohydraulic (EH) control systems introduce substantial reservoir-control advances by combining the benefits of both hydraulic and electric systems. This paper focuses on the features and benefits of a new EH control system, its reliability, and its overall performance when paired with interval control valves (ICVs) and other equipment.

The EH control system presented in this paper uses a novel approach to zonal control. The EH system uses two hydraulic lines and one electrical line to control up to 12 zones selectively. The system employs a unique addressing method that uses simple electronic components to selectively address different downhole tools. The system has the ability to provide the high motive power typical with existing hydraulic systems while providing fast system responses associated with electrical systems. Furthermore, system reliability is enhanced by fluid filling the electrical system with a pressurized non-conductive fluid biased to the external environment.

Careful consideration was given to both current electrical and hydraulic systems for deriving the system performance of the referenced EH system. One of the initial drivers for the EH system was the need to increase control while reducing the amount of control lines and surface infrastructure required to deploy such a system. Testing and deployment of the EH system suggests that the system response was able to meet or exceed current N+1 control systems while greatly increasing the amount of zones controlled. System response, system performance, surface infrastructure, ease of installation, number of control lines, and system modularity were assessed for this paper. Finally, the paper documents the cost savings and reliability obtained with the new EH module compared to traditional N+1 direct hydraulic control systems and current electrical systems.

This paper provides a thorough understanding of electric, hydraulic, and EH systems for downhole control in intelligent completions. It focuses on the comparison of all three systems but emphasizes the modularity of the EH system presented. Such modularity allows the EH system to be used in different intelligent completion applications while remaining compatible with other equipment deployed.
Barrier Management in Operation for the Rig Industry – A Joint Industry Project
Authors: Jonassen Øyvind , Sjølie Ellen
Published: March 2016

Effective barrier management is by most considered the fundamental principle for prevention and mitigation of major accidents in offshore drilling and production operations. The Rig Industry in Norway has long traditions when it comes to managing safety and assets, but previously no common practise amongst all the Rig Owners for how to meet the Norwegian regulatory requirements, was previously established.

Barrier management taps into safety and asset management practices by providing a more structured, integrated and systematic approach to managing major accident risk. To understand how the Rig Owner's can best prevent major accidents; focal persons from all the rig companies operating in Norway were involved in this project. During these workshops, all involved parties discussed and expressed their issues of concern, challenges and needs of the industry. Company specific information was openly shared, with the intention that it would be possible to learn from previous situations – to bring the business forward. By defining applicable terminology and explaining the rationale of barrier management, a framework was established as well as an understanding of how this could be implemented. First, definitions of relevant terminology were established, before the rationale of barrier management was explained. A framework was then developed, describing good pracitises for implemention of barrier management solutions in operations and how barrier performance can be maintained, including description of methods, tools and activities for systematic implementation.

The resulting barrier management framework can be used to support communication, consensus, decision making and action across technical disciplines and organizational boundaries. It has also given rig owners in Norway a common understanding and approach on how to meet the Petroleum Safety Authority expectations, and how to implement and manage barriers in daily operation to prevent major accidents.
Design and Application of High Temperature Seawater Based Fracturing Fluids in Saudi Arabia
Authors: AlMubarak Tariq , AlKhaldi Mohammed , AlGhamdi Abdulaziz
Published: March 2016

Typically, water-based fracturing treatments consume large volume of fresh water. Additionally, providing consistent fresh water sources is difficult and sometimes not feasible especially in remote areas and offshore. Therefore, several seawater tolerant guar gum-based fracturing fluids have been developed in efforts to preserve fresh water resources. However, none of these fluids meet the current requirements of preventing/minimizing fracture face skin and proppant conductivity impairment especially in unconventional wells in Saudi Arabia. This paper will go provide the process of resolving this issue.

Several experiments, tweaking and design iterations were conducted to tailor seawater-based fracturing fluids. These fluids were designed to have rheological properties that can carry and transport proppant under dynamic and static conditions. The optimized seawater based fracturing fluid recipes were developed such that no chemical scaling occurs when their filtrate is mixed with different formation brines. The tests were conducted utilizing HPHT viscometer, coreflood, zeta potential and aging cells at reservoir conditions.

The developed seawater-based fracturing fluids were optimized, with a viscosity above 200 cP at a shear rate of 100 S-1 and a temperature of 300°F. The use of polymeric scale inhibitors prevented the severe calcium sulfate scaling in mixtures of seawater and formation water at 250 and 300°F. Furthermore, designing a lower pH fracturing fluid prevented magnesium and calcium hydroxide scaling that occurred above pH of 9.5. It was also realized that some common scale inhibitors had negative impact on seawater viscosity due to its inevitable ability of chelating the crosslinker's zirconate ions. The developed seawater-based fracturing fluid was applied for the first time in conventional and unconventional wells in Saudi Arabia and showed very promising results which will be discussed in this paper.
Coiled Tubing Excitation Technology Leads to Greater Reach in the Wellbore
Authors: Benson A. , Elfar T. , Sew B. , Wijoseno D. A. , Devan T. , Manaf N.
Published: March 2016

Intervention operations using coiled tubing (CT) continue to be one of the fastest growing segments of the oil and gas industry. Over recent years, global shale exploration has demanded the need for continuous advances in technology to reach deeper, faster, more efficiently, and with the least amount of non-productive time.

The topic of this paper is specific to extended reach technology, and explains how an innovative tool that generates pressure pulses and transmits axial vibrations along the CT will improve weight transfer, reduce CT to wellbore friction, allow for more efficient CT applications, and allow CT intervention to reach depths not otherwise possible with conventional tool strings.

Case histories have shown that this proven technology has allowed CT operations to achieve significantly better results than anticipated. The technology has allowed for successful intervention and expanded the operating window of coiled tubing assemblies, ultimately resulting in a greater return on investment for the operator.

Continued need for robust technology with high durability and shorter tool length continues to be key for all new CT tool designs. Therefore, as coiled tubing intervention continues to move into more technically challenging areas, it is crucial that the industry learn from today and continue to engineer for tomorrow.
Improved Understanding of Foundation Strength for Piled Offshore Structures
Authors: Bucknell J. , Chen K. , Lamb A. R. , Gunn M. , Nichols N. W. , Ng S. M. , Khan R.
Published: March 2016

Within the oil and gas industry major inconsistencies have been found in the correlation of predicted pile response using design code prescribed methods and the measured response from installed on-line monitoring systems. This paper presents the first phase of a study conducted to determine whether a finite element continuum model which uses an elasto-plastic constitutive soil model can better determine the measured/observed response of piled offshore platforms.

The first phase of the study entailed a comparison of the measured natural period of an existing platform to the natural period determined numerically using a dynamic eigenvalue analysis with nonlinear soil springs. Sensitivity studies were also conducted to identify how modelled parameters such as topsides mass, conductor mass and marine growth affected the calculated natural period of an existing platform. Single pile models were also developed for detailed finite element (FE) analyses using the nonlinear springs (API soil springs) and a continuum soil model with the soil properties defined using the Mohr-Coulomb plasticity constitutive soil model.

The results of the analyses have confirmed industry observations that, even accounting for the various parameters considered in the sensitivity studies, the design code derived soil springs show poor correlation to the measured response of the jacket. The dominant reason for this is the lateral stiffness (p-y) of the API derived soil springs which required an amplification factor in the range of 8-10 to obtain a suitable correlation to the measured jacket response.

The continuum model demonstrated a significantly improved correlation between the numerically derived pile response and the measured data. The numerical representation of the soil-pile interaction described in this paper provides a more realistic determination of the structural response of the modelled platform. The results obtained have major implications for both the design and assessment of offshore structures. An increased lateral soil stiffness will largely eliminate the foundation failures predicted by conventional ultimate strength assessments and improve correlation to observed post hurricane structural performance.

In the case of platform risk assessments, this improved representation of the soil-pile interaction will reduce the industry observed excessive conservatism in the prediction of failure probabilities of existing offshore facilities. In extreme cases, platforms have had to be strengthened or even removed based on predictions of foundation failures that were inconsistent with measured (OLM systems) and observed performance (hurricane survivals). Based on the results obtained from the first phase of this study, further work is planned to validate the FE continuum approach single pile model and finally provide a numerical solution for pile-soil interaction which can be easily adopted by practicing engineers in the oil and gas industry.
Mid Depth Buoys Design for Long Life Using Syntactic Foam Buoyancy, Redundant and Replaceable Tether Systems
Authors: Aberle G. E. , Christensen L.
Published: March 2016

Riser systems utilize various configurations depending on water depth, size, quantity, environment etc. In the Ichthys development, three systems are utilized, Fixed-S, Lazy-S and Lazy-Wave system. The riser system design [1] and the riser support structure [2] in the Fixed-S configuration are the subject of other papers and the current paper is related to the mid depth buoys in the Lazy-S configurations.

Two large MDBs each supporting five risers were designed for the initial phase of the development, one for each mooring sector of a Floating Production Storage and Offloading vessel (FPSO) which has a 3×7 mooring system.

Each MDB is moored to a gravity base via primary chain and redundant, secondary polyester tether systems. Large syntactic foam modules supported in a latticed buoy structure space frame provide the buoyancy to support the riser system for a 40-year design life.

This paper presents the evolution of the design, featuring:

Securement of syntactic foam in the buoy structure, to accommodate dimensional change of foam. Dimensional control of the buoy structure and syntactic foam modules, during fabrication. Configuration of the structures to cater for efficient installation of large volumes of syntactic foam during fabrication. Tensioning system to manage the redundant secondary tether system. Contingency "Diverless Tether Replacement Procedure" to design features for future implementation if needed. Management of the system net buoyancy throughout the design, fabrication and installation processes.

Syntactic foam buoyancy in long life, mid depth buoys avoids the need for the certification and maintenance of pressure vessels, as can be required of steel tanks. Testing verified that bulk syntactic foam exhibits minimal degradation from dropped object, impact damage. Coupled with an efficient structural containment, the sensitivity of the design to "damaged" state conditions was essentially eliminated.

Chain tether systems are ideally suited to conventional mid depth buoy installation techniques. Fully redundant secondary tether systems, can be effectively incorporated into buoy system designs, to enhance greatly the system reliability over long operating lives. The manufacturing length tolerances of tether systems required a unique system for managing the ‘in place’ tension of secondary tethers to ensure their longevity.
A More Efficient Use of MEG to Fully Inhibit Hydrates with Reduced Cost
Authors: Grzelak Eric M. , Stenhaug Morten
Published: March 2016

Monoethylene glycol (MEG) is the primary hydrate inhibitor used in today's large gas fields. To fully prevent hydrate formation, high dosage rates of over 1 gallon of MEG per gallon of produced water may be required. As a result of these high rates, MEG usage can reach into the 100s of tonnes per day for a field.

The first estimate of MEG requirement stems from subsurface analysis of expected water production and it becomes the starting point for a design process that may lead to excess. A standard inhibition system must accomodate large uncertainties due to inaccurate MEG distribution to each well, inaccurate measurement of water production from each well, and difficulties recovering and reclaiming the MEG through topsides processing. The compounding of these uncertainties then requires a planned overdose of MEG to insure total hydrate inhibition. Determining the planned overdose and the necessary equipment to achieve it often leads to a doubling of system size, which can push the capcity of the MEG system into the 1000s of tonnes with a concurrent major increase in CAPEX. Likewise, the operation of an oversized systems leads to a significant increase in OPEX from energy usage for recovery, MEG replacement from loss, and other factors.

To combat this excess cost and make more fields economical, a hydrate management system has been identified that ties together industry proven equipment into an intelligently operated package. Uncertainties are reduced through the use of industry leading chemical injection metering valves to pinpoint and control the distribution of MEG, accurate metering using a variety of technologies to target exactly the amount of water in need of hydrate inhibition, energy efficient MEG recovery with up to 100% salt and solids removal, and real-time condition monitoring, performance evaluation, and process modeling to ensure that the whole system is operating optimally to prevent hydrates under any circumstance.

Tightening the use of MEG for hydrate inhibition with the hydrate management system can create substantial operational savings over the life of the field and, should it be included early enough in the design phase, has the ability to reduce overall system size resulting in substantial capital savings as well.
A modified Verhoeff-van Gieson elastin histochemical stain to enable pulmonary arterial hypertension model characterization
Authors: Percival K.R. , Radi Z. A.
Published: March 2016

Optimal histochemical staining is critical to ensure excellent quality stained sections to enable light microscopic and histomorphometric image analysis.  Verhoeff-van Gieson is the most widely used histochemical stain for the visualization of vascular elastic fibers. However, it is notoriously difficult to differentiate fine elastic fibers of small vasculature to enable histomorphometric image analysis of vasculature size characterization especially in organs such as the lung. A tissue fixation regime of 10% neutral buffered formalin with subsequent fixation in 70% ethanol further compounds the problem of small vessel staining and identification.  Therefore, a modified Verhoeff's elastin stain was developed as a reliable method to optimally highlight the internal and external elastic lamina of small arteries (50-100 µm) and intra-acinar vessels (10-50 µm) in 3 µm thick lung tissue sections from models of pulmonary arterial hypertension.  This modified Verhoeff's elastin stain demonstrated optimal staining of fine elastic fibers of pulmonary blood vessels. As a result, high-quality histomorphometric image analysis evaluation of vessel wall thickness in small arteries and intra-acinar vessels was successfully accomplished.  In conclusion, modification of the standard Verhoeff-van Gieson histochemical stain is needed to visualize small caliber vessels' elastic fibers especially in tissues not fixed in 10% neutral buffered formalin only.
Thoracic Actinomycosis: A Rare Occurrence
Authors: Jehangir Waqas , Vaidya Bhumesh , Enakuaa Souad , Raoof Nazar , Middleton John R. , Yousif Abdalla
Published: March 2016

Actinomyces israelii is a branching anaerobic bacilli microorganism that can be identified as normal flora throughout various portions of the human alimentary canal. It is crucial to establish a diagnosis as treatment will vary depending on the clinical form of the disease. We report a case of a 78-year-old man who initially presented with an acute onset of respiratory distress displayed contrast leakage on computed tomography from the site of a previously inserted esophageal stent for an unsuccessful surgical repair of an esophageal rupture. In addition to the contrast leakage, the presence of a bronchopulmonary fistula imaging prompted the need for further investigation. Our patient was empirically treated with antibiotics and obtained blood cultures, which returned positive A. israelii.
First Report of Acute Postoperative Endophthalmitis Caused by Rothia Mucilaginosa after Phacoemulsification
Authors: Álvarez-Ramos Pablo , Del Moral-Ariza Amparo , Alonso-Maroto José M. , Marín-Casanova Pilar , Calandria-Amigueti José M. , Rodríguez-Iglesias Manuel , Rodríguez de la Rúa Enrique
Published: March 2016

We aimed at reporting the first case of rapidly progressive acute postoperative endophthalmitis after phacoemulsification cataract surgery in an immunocompetent patient caused by Rothia mucilaginosa. An immunocompetent patient manifested endophthalmitis signs 48 hours after an uncomplicated cataract surgery by phacoemulsification. A bacteria of the family Micrococcaceae was cultured in the vitreous biopsy, namely R. mucilaginosa. The patient did not show a favorable clinical response after vitrectomy and systemic, intravitreal, and topical fortified antibiotics. The patient’s eye was very painful, and consequently, it deemed necessary to perform an evisceration. R. mucilaginosa may be an aggressive etiologic agent for postoperative endophthalmitis. Although the isolated R. mucilaginosa was susceptible to empirical treatment, it was impossible to control the infection with standard treatment, probably due to its ability to create a biofilm around the intraocular lens.
Positron Emission Tomography Findings in Atypical Polypoid Adenomyoma
Authors: Fukami Tatsuya , Yoshikai Tomonori , Tsujioka Hiroshi , Tohyama Atsushi , Sorano Sumire , Matsuoka Sakiko , Yamamoto Hiroko , Nakamura Sumie , Goto Maki , Matsuoka Ryoei , Oya Masafumi , Torii Yoshikuni , Eguchi Fuyuki
Published: March 2016

Atypical polypoid adenomyoma (APAM) is a rare polypoid tumor of the uterus composed of atypical endometrial glands surrounded by smooth muscle. A 29-year-old nulligravida, was clinically diagnosed with endocervical myoma and underwent trans-uterine cervical resection with hysteroscope. The histopathological diagnosis of specimens was APAM. Eight months later, she diagnosed recurrent uterine tumor. The positron emission tomography (PET-CT) imaging showed an increased fluorodeoxyglucose uptake. She has performed hysterectomy and was diagnosed APAM. Therapy for APAM depends on multiple factors such as age at presentation and desire for childbearing among others. This is the first report of PET-CT findings in APAM.
Idealizations of Uncertainty, and Lessons from Artificial Intelligence
Authors: Smith Robert Elliott
Published: March 2016

At a time when economics is giving intense scrutiny to the likely impact of artificial intelligence (AI) on the global economy, this paper suggests the two disciplines face a common problem when it comes to uncertainty. It is argued that, despite the enormous achievements of AI systems, it would be a serious mistake to suppose that such systems, unaided by human intervention, are as yet any nearer to providing robust solutions to the problems posed by Keynesian uncertainty. Under the radically uncertain conditions, human decision-making (for all its problems) has proved relatively robust, while decision making relying solely on deterministic rules or probabilistic models is bound to be brittle. AI remains dependent on techniques that are seldom seen in human decision-making, including assumptions of fully enumerable spaces of future possibilities, which are rigorously computed over, and extensively searched. Discussion of alternative models of human decision making under uncertainty follows, suggesting a future research agenda in this area of common interest to AI and economics.
Simulating the formation of carbonaceous aerosol in a European Megacity (Paris) during the MEGAPOLI summer and winter campaigns
Authors: Fountoukis Christos , Megaritis Athanasios G. , Skyllakou Ksakousti , Charalampidis Panagiotis E. , Denier van der Gon Hugo A. C. , Crippa Monica , Prévôt André S. H. , Fachinger Friederike , Wiedensohler Alfred , Pilinis Christodoulos , Pandis Spyros N.
Published: March 2016

Abstract. We use a three-dimensional regional chemical transport model (PMCAMx) with high grid resolution and high-resolution emissions (4 × 4 km2) over the Paris greater area to simulate the formation of carbonaceous aerosol during a summer (July 2009) and a winter (January/February 2010) period as part of the MEGAPOLI (megacities: emissions, urban, regional, and global atmospheric pollution and climate effects, and Integrated tools for assessment and mitigation) campaigns. Model predictions of carbonaceous aerosol are compared against Aerodyne aerosol mass spectrometer and black carbon (BC) high time resolution measurements from three ground sites. PMCAMx predicts BC concentrations reasonably well reproducing the majority (70 %) of the hourly data within a factor of two during both periods. The agreement for the summertime secondary organic aerosol (OA) concentrations is also encouraging (mean bias = 0.1 µg m−3) during a photochemically intense period. The model tends to underpredict the summertime primary OA concentrations in the Paris greater area (by approximately 0.8 µg m−3) mainly due to missing primary OA emissions from cooking activities. The total cooking emissions are estimated to be approximately 80 mg d−1 per capita and have a distinct diurnal profile in which 50 % of the daily cooking OA is emitted during lunch time (12:00–14:00 LT) and 20 % during dinner time (20:00–22:00 LT). Results also show a large underestimation of secondary OA in the Paris greater area during wintertime (mean bias =  −2.3 µg m−3) pointing towards a secondary OA formation process during low photochemical activity periods that is not simulated in the model.
Parameterization of Single Scattering Albedo (SSA) and Absorption Angstrom Exponent (AAE) with EC/OC for Aerosol Emissions from Biomass Burning
Authors: Pokhrel Rudra P. , Wagner Nick L. , Langridge Justin M. , Lack Daniel A. , Jayarathne Thilina , Stone Elizabeth A. , Stockwell Chelsea E. , Yokelson Robert J. , murphy Shane M.
Published: March 2016

Abstract. Single scattering albedo (SSA) and absorption angstrom exponent (AAE) are two critical parameters in determining the impact of absorbing aerosol on the Earth's radiative balance. Aerosol emitted by biomass burning represent a significant fraction of absorbing aerosol globally, but it remains difficult to accurately predict SSA and AAE for biomass burning aerosol. Black carbon (BC), brown carbon (BrC), and non-absorbing coatings all make significant contributions to the absorption coefficient of biomass burning aerosol. SSA and AAE cannot be directly inferred based on fuel type because they depend strongly on burn conditions. It has been suggested that SSA can be effectively parameterized via the modified combustion efficiency (MCE) of a biomass-burning event and that this would be useful because emission factors for the MCE of a large number of fuels are available. Here we demonstrate, with data from the FLAME-4 experiment, that for a wide variety of globally relevant biomass fuels, over a range of combustion conditions, parameterizations of SSA and AAE based on the elemental carbon (EC) to organic carbon (OC) mass ratio are quantitatively superior to parameterizations based on MCE. We show that the EC/OC ratio and the ratio of EC/(EC + OC) both have significantly better correlations with SSA than MCE. Furthermore, the relationship of EC/(EC + OC) with SSA is linear. These improved parameterizations are significant because, similar to MCE, emission factors for EC (or black carbon) and OC are available for a wide range of biomass fuels. Fitting SSA with MCE yields correlation coefficients (Pearson's r) of ~ 0.65 at the visible wavelengths of 405, 532, and 660 nm while fitting SSA with EC/OC or EC/(EC + OC) yields a Pearson's r of 0.94–0.97 at these same wavelengths. The strong correlation coefficient at 405 nm (r = 0.97) suggests that parameterizations based on EC/OC or EC/(EC + OC) have good predictive capabilities even for fuels in which brown carbon absorption is significant. Notably, these parameterizations are effective for emissions from Indonesian peat, which have very little black carbon but significant brown carbon (SSA = 0.99 ± 0.07 at 532 and 660 nm, SSA = 0.93 ± 0.06 at 405 nm). Finally, we demonstrate that our parameterization based on EC/(EC + OC) accurately predicts SSA during the first few hours of plume aging with data from Yokelson et al. (2009) gathered during a biomass burning event in the Yucatan Peninsula of Mexico.
Nitrogen dioxide stratospheric column at the subtropical NDACC station of Izaña from DOAS, FTIR and satellite instrumentation
Authors: Robles-Gonzalez Cristina , Navarro-Comas Mónica , Puentedura Olga , Schneider Matthias , Hase Frank , Garcia Omaira , Blumenstock Thomas , Gil-Ojeda Manuel
Published: March 2016

Abstract. A 13-years analysis (2000–2012) of the NO2 vertical column densities (VCD) derived from ground-based (GB) instruments and satellites has been carried out over the Izaña NDACC (Network for the Detection of the Atmospheric Composition Change) subtropical site. Ground-based DOAS (Differential Optical Absorption Spectroscopy) and FTIR (Fourier Transform InfraRed spectroscopy) instruments are intercompared to test mutual consistency and then use for validation of stratospheric NO2 from OMI (Ozone Monitoring Instrument) and SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY). The intercomparison has been carried out taking into account the various differences existing in instruments, namely temporal coincidence, collocation, sensitivity, field of view, etc. The paper highlights the importance of considering an "effective solar zenith angle" instead of the actual one when comparing direct sun instruments with zenith sky ones for a proper photochemical correction. Results show that NO2 vertical column densities mean relative difference between FTIR and DOAS instruments is 2.8 ± 10.7 % for AM data. Both instruments properly reproduce the NO2 seasonal and the interannual variation. Mean relative difference of the stratospheric NO2 derived from OMI and DOAS is −0.2 ± 8.7 % and from OMI and FTIR is −1.6 ± 6.7. SCIAMACHY mean relative difference is of 3.7 ± 11.7 % and −5.7 ± 11.0 % for DOAS and FTIR, respectively. Note that the days used for the intercomparison are not the same for all the pairs of instruments since it depends on the availability of data. The discrepancies are found to be seasonally dependent with largest differences in winter and excellent agreement in the spring months (AMJ). A preliminary analysis of NO2 trends has been carried out with the available data series. Results show positive values in all instruments but larger values on the ground-based than that expected by nitrous oxide oxidation. The possible reasons of the discrepancy between instruments and the positive trends are discussed in the text.
Lidar-Radiometer Inversion Code (LIRIC) for the retrieval of vertical aerosol properties from combined lidar/radiometer data: development and distribution in EARLINET
Authors: Chaikovsky Anatoli , Dubovik Oleg , Holben Brent , Bril Andrey , Goloub Philippe , Tanré Didier , Pappalardo Gelsomina , Wandinger Ulla , Chaikovskaya Ludmila , Denisov Sergey , Grudo Jan , Lopatin Anton , Karol Yana , Lapyonok Tatsiana , Amiridis Vassilis , Ansmann Albert , Apituley Arnoud , Allados-Arboledas Lucas , Binietoglou Ioannis , Boselli Antonella , D'Amico Giuseppe , Freudenthaler Volker , Giles David , Granados-Muñoz María José , Kokkalis Panayotis , Nicolae Doina , Oshchepkov Sergey , Papayannis Alex , Perrone Maria Rita , Pietruczuk Alexander , Rocadenbosch Francesc , Sicard Michaël , Slutsker Ilya , Talianu Camelia , De Tomasi Ferdinando , Tsekeri Alexandra , Wagner Janet , Wang Xuan
Published: March 2016

Abstract. This paper presents a detailed description of LIRIC (LIdar-Radiometer Inversion Code) algorithm for simultaneous processing of coincident lidar and radiometric (sun photometric) observations for the retrieval of the aerosol concentration vertical profiles. As the lidar/radiometric input data we use measurements from European Aerosol Research Lidar Network (EARLINET) lidars and collocated sun-photometers of Aerosol Robotic Network (AERONET). The LIRIC data processing provides sequential inversion of the combined lidar and radiometric data. The algorithm starts with the estimations of column-integrated aerosol parameters from radiometric measurements followed by the retrieval of height dependent concentrations of fine and coarse aerosols from lidar signals using integrated column characteristics of aerosol layer as a priori constraints. The use of polarized lidar observations allows us to discriminate between spherical and non-spherical particles of the coarse aerosol mode.The LIRIC software package was implemented and tested at a number of EARLINET stations. Intercomparison of the LIRIC-based aerosol retrievals was performed for the observations by seven EARLINET lidars in Leipzig, Germany on 25 May 2009. We found close agreement between the aerosol parameters derived from different lidars that supports high robustness of the LIRIC algorithm. The sensitivity of the retrieval results to the possible reduction of the available observation data is also discussed.
Intercomparison of in situ water vapor balloon-borne measurements from Pico-SDLA H2O and FLASH-B in the tropical UTLS
Authors: Ghysels Mélanie , Riviere Emmanuel D. , Khaykin Sergey , Stoeffler Clara , Amarouche Nadir , Pommereau Jean-Pierre , Held Gerhard , Durry Georges
Published: March 2016

Abstract. In this paper we compare water vapor mixing ratio measurements from two quasi-parallel flights of the Pico-SDLA H2O and FLASH-B hygrometers. The measurements were made on 10 February 2013 and 13 March 2012, respectively, in the tropics near Bauru, São Paulo state, Brazil during an intense convective period. Both flights were performed as part of a French scientific project, TRO-Pico, to study the impact of the deep-convection overshoot on the water budget. Only a few instruments that permit the frequent sounding of stratospheric water vapor can be flown within small-volume weather balloons. Technical difficulties preclude the accurate measurement of stratospheric water vapor with conventional in situ techniques. The instruments described here are simple and lightweight, which permits their low-cost deployment by non-specialists aboard a small weather balloon. We obtain mixing ratio retrievals which agree above the cold-point tropopause to within 1.9 and 0.5 % for the first and second flights, respectively. This level of agreement for balloon-borne measured stratospheric water mixing ratio constitutes one of the best agreement reported in the literature. Because both instruments show similar profiles within their combined uncertainties, we conclude that the Pico-SDLA H2O and FLASH-B data sets are mutually consistent.
Three-model ensemble wind prediction in southern Italy
Authors: Torcasio Rosa Claudia , Federico Stefano , Calidonna Claudia Roberta , Avolio Elenio , Drofa Oxana , Landi Tony Christian , Malguzzi Piero , Buzzi Andrea , Bonasoni Paolo
Published: March 2016

Abstract. Quality of wind prediction is of great importance since a good wind forecast allows the prediction of available wind power, improving the penetration of renewable energies into the energy market. Here, a 1-year (1 December 2012 to 30 November 2013) three-model ensemble (TME) experiment for wind prediction is considered. The models employed, run operationally at National Research Council – Institute of Atmospheric Sciences and Climate (CNR-ISAC), are RAMS (Regional Atmospheric Modelling System), BOLAM (BOlogna Limited Area Model), and MOLOCH (MOdello LOCale in H coordinates). The area considered for the study is southern Italy and the measurements used for the forecast verification are those of the GTS (Global Telecommunication System). Comparison with observations is made every 3 h up to 48 h of forecast lead time. Results show that the three-model ensemble outperforms the forecast of each individual model. The RMSE improvement compared to the best model is between 22 and 30 %, depending on the season. It is also shown that the three-model ensemble outperforms the IFS (Integrated Forecasting System) of the ECMWF (European Centre for Medium-Range Weather Forecast) for the surface wind forecasts. Notably, the three-model ensemble forecast performs better than each unbiased model, showing the added value of the ensemble technique. Finally, the sensitivity of the three-model ensemble RMSE to the length of the training period is analysed.
Investigations on the magnetic field coupling of automotive high voltage systems to determine relevant parameters for an EMR-optimized designing
Authors: Krause David , John Werner , Weigel Robert
Published: March 2016

Abstract. The implementation of electrical drive trains in modern vehicles is a new challenge for EMC development. This contribution depicts a variety of investigations on magnetic field coupling of automotive high-voltage (HV) systems in order to fulfil the requirements of an EMR-optimized designing. The theoretical background is discussed within the scope of current analysis, including the determination of current paths and spectral behaviour. It furthermore presents models of shielded HV cables with particular focus on the magnetic shielding efficiency. Derived findings are validated by experimental measurements of a state-of-the-art demonstrator on system level. Finally EMC design rules are discussed in the context of minimized magnetic fields.
Stream biogeochemical and suspended sediment responses to permafrost degradation in stream banks in Taylor Valley, Antarctica
Authors: Gooseff Michael N. , Van Horn David , Sudman Zachary , McKnight Diane M. , Welch Kathleene A. , Lyons William B.
Published: March 2016

Abstract. Stream channels in the McMurdo Dry Valleys are characteristically wide, incised, and stable. At typical flows, streams occupy a fraction of the oversized channels, providing habitat for algal mats. In January 2012, we discovered substantial channel erosion and subsurface thermomechanical erosion undercutting banks of the Crescent Stream. We sampled stream water along the impacted reach and compared concentrations of solutes to the long-term data from this stream ( ∼  20 years of monitoring). Thermokarst-impacted stream water demonstrated higher electrical conductivity, and concentrations of chloride, sulfate, sodium, and nitrate than the long-term medians. These results suggest that this mode of lateral permafrost degradation may substantially impact stream solute loads and potentially fertilize stream and lake ecosystems. The potential for sediment to scour or bury stream algal mats is yet to be determined, though it may offset impacts of associated increased nutrient loads to streams.
Historical reconstruction of ocean acidification in the Australian region
Authors: Lenton Andrew , Tilbrook Bronte , Matear Richard J. , Sasse Tristan P. , Nojiri Yukihiro
Published: March 2016

Abstract. The ocean has become more acidic over the last 200 years in response increasing atmospheric carbon dioxide (CO2) levels. Documenting how the ocean has changed is critical for assessing how these changes impact marine ecosystems and for the management of marine resources. Here we use present-day ocean carbon observations, from shelf and offshore waters around Australia, combined with neural network mapping of CO2, sea surface temperature, and salinity to estimate the current seasonal and regional distributions of carbonate chemistry (pH and aragonite saturation state). The observed changes in atmospheric CO2 and sea surface temperature (SST) and climatological salinity are then used to reconstruct pH and aragonite saturation state changes over the last 140 years (1870–2013). The comparison with data collected at Integrated Marine Observing System National Reference Station sites located on the shelf around Australia shows that both the mean state and seasonality in the present day are well represented, with the exception of sites such as the Great Barrier Reef. Our reconstruction predicts that since 1870 decrease in aragonite saturation state of 0.48 and of 0.09 in pH has occurred in response to increasing oceanic uptake of atmospheric CO2. Large seasonal variability in pH and aragonite saturation state occur in southwestern Australia driven by ocean dynamics (mixing) and in the Tasman Sea by seasonal warming (in the case of the aragonite saturation state). The seasonal and historical changes in aragonite saturation state and pH have different spatial patterns and suggest that the biological responses to ocean acidification are likely to be non-uniform depending on the relative sensitivity of organisms to shifts in pH and saturation state. This new historical reconstruction provides an important link to biological observations that will help to elucidate the consequences of ocean acidification.
Toxic Levels of Some Heavy Metals in Drinking Network Surface Water of Damietta Governorate, Egypt
Authors: EL-Bady M. S. M.
Published: March 2016

Abstract. In this paper, the heavy metals of the surface drinking water of Damietta governorate were evaluated. Damietta district, Farascore City, EL-Zarka City and Kafr Saad City are the main locations of drinking water pollution. The villages of the Damietta governorate have concentration values less than the permissible limits of World Health Organization (WHO) and Egyptian Ministry Health (EMH).
CPLFD-GDPT5: High-resolution gridded daily precipitation and temperature data set for two largest Polish river basins
Authors: Berezowski Tomasz , Szcześniak Mateusz , Kardel Ignacy , Michałowski Robert , Okruszko Tomasz , Mezghani Abdelkader , Piniewski Mikołaj
Published: March 2016

Abstract. The CHASE-PL (Climate change impact assessment for selected sectors in Poland) Forcing Data–Gridded Daily Precipitation & Temperature Dataset–5 km (CPLFD-GDPT5) consists of 1951–2013 daily minimum and maximum air temperatures and precipitation totals interpolated onto a 5 km grid based on daily meteorological observations from the Institute of Meteorology and Water Management (IMGW-PIB; Polish stations), Deutscher Wetterdienst (DWD, German and Czech stations), and European Climate Assessment and Dataset (ECAD) and National Oceanic and Atmosphere Administration–National Climatic Data Center (NOAA-NCDC) (Slovak, Ukrainian, and Belarusian stations). The main purpose for constructing this product was the need for long-term aerial precipitation and temperature data for earth-system modelling, especially hydrological modelling. The spatial coverage is the union of the Vistula and Oder basins and Polish territory. The number of available meteorological stations for precipitation and temperature varies in time from about 100 for temperature and 300 for precipitation in the 1950s up to about 180 for temperature and 700 for precipitation in the 1990s. The precipitation data set was corrected for snowfall and rainfall under-catch with the Richter method. The interpolation methods were kriging with elevation as external drift for temperatures and indicator kriging combined with universal kriging for precipitation. The kriging cross validation revealed low root-mean-squared errors expressed as a fraction of standard deviation (SD): 0.54 and 0.47 for minimum and maximum temperature, respectively, and 0.79 for precipitation. The correlation scores were 0.84 for minimum temperatures, 0.88 for maximum temperatures, and 0.65 for precipitation. The CPLFD-GDPT5 product is consistent with 1971–2000 climatic data published by IMGW-PIB. We also confirm good skill of the product for hydrological modelling by performing an application using the Soil and Water Assessment Tool (SWAT) in the Vistula and Oder basins. Link to the data set: doi:10.4121/uuid:e939aec0-bdd1-440f-bd1e-c49ff10d0a07.
UNDERWATER CALIBRATION OF DOME PORT PRESSURE HOUSINGS
Authors: Nocerino E. , Menna F. , Fassi F. , Remondino F.
Published: March 2016

Abstract. Underwater photogrammetry using consumer grade photographic equipment can be feasible for different applications, e.g. archaeology, biology, industrial inspections, etc. The use of a camera underwater can be very different from its terrestrial use due to the optical phenomena involved. The presence of the water and camera pressure housing in front of the camera act as additional optical elements. Spherical dome ports are difficult to manufacture and consequently expensive but at the same time they are the most useful for underwater photogrammetry as they keep the main geometric characteristics of the lens unchanged. Nevertheless, the manufacturing and alignment of dome port pressure housing components can be the source of unexpected changes of radial and decentring distortion, source of systematic errors that can influence the final 3D measurements. The paper provides a brief introduction of underwater optical phenomena involved in underwater photography, then presents the main differences between flat and dome ports to finally discuss the effect of manufacturing on 3D measurements in two case studies.
ROLE OF TIE-POINTS DISTRIBUTION IN AERIAL PHOTOGRAPHY
Authors: Kerner S. , Kaufman I. , Raizman Y.
Published: March 2016

Abstract. Automatic image matching algorithms, and especially feature-based methods, profoundly changed our understanding and requirements of tie points. The number of tie points has increased by orders of magnitude, yet the notions of accuracy and reliability of tie points remain equally important. The spatial distribution of tie points is less predictable, and is subject only to limited control. Feature-based methods also highlighted a conceptual division of the matching process into two separate stages – feature extraction and feature matching. In this paper we discuss whether spatial distribution requirements, such as Von Gruber positions, are still relevant to modern matching methods. We argue that forcing such patterns might no longer be required in the feature extraction stage. However, we claim spatial distribution is important in the feature matching stage. We will focus on terrains that are notorious for difficult matching, such as water bodies, with real data obtained by users of VisionMap’s A3 Edge camera and LightSpeed photogrammetric suite.
EXTERIOR ORIENTATION OF HYPERSPECTRAL FRAME IMAGES COLLECTED WITH UAV FOR FOREST APPLICATIONS
Authors: Berveglieri A. , Tommaselli A. M. G.
Published: March 2016

Abstract. This paper describes a preliminary study on the image orientation acquired by a hyperspectral frame camera for applications in small tropical forest areas with dense vegetation. Since access to the interior of forests is complicated and Ground Control Points (GCPs) are not available, this study conducts an assessment of the altimetry accuracy provided by control targets installed on one border of an image block, simulating it outside a forest. A lightweight Unmanned Aerial Vehicle (UAV) was equipped with a hyperspectral camera and a dual-frequency GNSS receiver to collect images at two flying strips covering a vegetation area. The assessment experiments were based on Bundle Block Adjustment (BBA) with images of two spectral bands (from two sensors) using several weighted constraints in the camera position. Trials with GCPs (presignalized targets) positioned only on one side of the image block were compared with trials using GCPs in the corners. Analyses were performed on altimetry discrepancies obtained from altimetry checkpoints. The results showed a discrepancy in Z coordinate of approximately 40 cm using the proposed technique, which is sufficient for applications in forests.