bluuebunny/crossref_metadata_2025 huggingface dataset:
Landing Error Scoring System Differences Between Single-Sport and Multi-Sport Female High School–Aged Athletes
Authors: Beese Mark E. , Joy Elizabeth , Switzler Craig L. , Hicks-Little Charlie A.
Published: March 2017

Context

 Single-sport specialization (SSS) is becoming more prevalent in youth athletes. Deficits in functional movement have been shown to predispose athletes to injury. It is unclear whether a link exists between SSS and the development of functional movement deficits that predispose SSS athletes to an increased risk of knee injury.

Objective

 To determine whether functional movement deficits exist in SSS athletes compared with multi-sport (M-S) athletes.

Design

 Cross-sectional study.

Setting

 Soccer practice fields.

Patients or Other Participants

 A total of 40 (21 SSS [age = 15.05 ± 1.2 years], 19 M-S [age = 15.32 ± 1.2 years]) female high school athlete volunteers were recruited through local soccer clubs. All SSS athletes played soccer.

Intervention(s)

 Participants were grouped into 2 categories: SSS and M-S. All participants completed 3 trials of the standard Landing Error Scoring System (LESS) jump-landing task. They performed a double-legged jump from a 30-cm platform, landing on a rubber mat at a distance of half their body height. Upon landing, participants immediately performed a maximal vertical jump.

Main Outcome Measure(s)

 Values were assigned to each trial using the LESS scoring criteria. We averaged the 3 scored trials and then used a Mann-Whitney U test to test for differences between groups. Participant scores from the jump-landing assessment for each group were also placed into the 4 defined LESS categories for group comparison using a Pearson χ2 test. The α level was set a priori at .05.

Results

 Mean scores were 6.84 ± 1.81 for the SSS group and 6.07 ± 1.93 for the M-S group. We observed no differences between groups (z = −1.44, P = .15). A Pearson χ2 analysis revealed that the proportions of athletes classified as having excellent, good, moderate, or poor LESS scores were not different between the SSS and M-S groups ( = 1.999, P = .57).

Conclusions

 Participation in soccer alone compared with multiple sports did not affect LESS scores in adolescent female soccer players. However, the LESS scores indicated that most female adolescent athletes may be at an increased risk for knee injury, regardless of the number of sports played.
Concussion-Management Practice Patterns of National Collegiate Athletic Association Division II and III Athletic Trainers: How the Other Half Lives
Authors: Buckley Thomas A. , Burdette Glenn , Kelly Kassandra
Published: March 2017

Context

The National Collegiate Athletic Association (NCAA) has published concussion-management practice guidelines consistent with recent position and consensus statements. Whereas NCAA Division I athletic trainers appear highly compliant, little is known about the concussion-management practice patterns of athletic trainers at smaller institutions where staffing and resources may be limited.

Objective

To descriptively define the concussion-management practice patterns of NCAA Division II and III athletic trainers.

Design

Cross-sectional study.

Setting

Web-based questionnaire.

Patients or Other Participants

A total of 755 respondents (response rate = 40.2%) from NCAA Division II and Division III institutions.

Main Outcome Measure(s)

The primary outcome measures were the rate of multifaceted concussion-assessment techniques, defined as 3 or more assessments; the specific practice patterns of each assessment battery; and tests used during a clinical examination.

Results

Most respondents indicated using a multifaceted assessment during acute assessment (Division II = 76.9%, n = 473; Division III = 76.0%, n = 467) and determination of recovery (Division II = 65.0%, n = 194; Division III = 63.1%, n = 288) but not at baseline (Division II = 43.1%, n = 122; Division III = 41.0%, n = 176). Typically, when a postconcussion assessment was initiated, testing occurred daily until baseline values were achieved, and most respondents (80.6% [244/278]) reported using a graded exercise protocol before return to participation.

Conclusions

We found limited use of the multifaceted assessment battery at baseline but higher rates at both acute assessment and return-to-participation time points. A primary reason cited for not using test-battery components was a lack of staffing or funding for the assessments. We observed limited use of neuropsychologists to interpret neuropsychological testing. Otherwise, most respondents reported concussion-management protocols consistent with recommendations, including a high level of use of objective measures and incorporation of a progressive return-to-participation protocol.
Sharp geometric quantitative estimates
Authors: Giannetti Flavia
Published: March 2017

Let

E \subset B \subset \mathbb R^n

be closed, bounded, convex sets. The monotonicity of the surface areas tells us that

\mathcal{H}^{n-1}(\partial E) \leqslant \mathcal{H}^{n-1}(\partial B).

We give quantitative estimates from below of the difference

\delta(E;B)=\mathcal{H}^{n-1}(\partial B)-\mathcal{H}^{n-1}(\partial E)

in the cases

n=2

and

n=3

. As an application, considered a decomposition of a closed and bounded set into a number

k

of convex pieces, we deduce an estimate from below of the minimal number of convex components that may exist.
Comparing monotonicity formulas for electrostatic potentials and static metrics
Authors: Agostiniani Virginia , Mazzieri Lorenzo
Published: March 2017

In this note we survey and compare the monotonicity formulas recently discovered by the authors in [1] and [2] in the context of classical potential theory and in the study of static metrics, respectively. In both cases we discuss the most significant implications of the monotonicity formulas in terms of sharp analytic and geometric inequalities. In particular, we derive the classical Willmore inequality for smooth compact hypersurfaces embedded in Euclidean space and the Riemannian Penrose inequality for static Black Holes with connected horizon.
Some remarks on the $L^p$ regularity of second derivatives of solutions to non-divergence elliptic equations and the Dini condition
Authors: Escauriaza Luis , Montaner Santiago
Published: March 2017

In this note we prove an end-point regularity result on the

L^p

integrability of the second derivatives of solutions to non-divergence form uniformly elliptic equations whose second derivatives are a priori only known to be integrable. The main assumption on the elliptic operator is the Dini continuity of the coefficients. We provide a counterexample showing that the Dini condition is somehow optimal. We also give a counterexample related to the
BMO
regularity of second derivatives of solutions to elliptic equations. These results are analogous to corresponding results for divergence form elliptic equations in [3, 15].
Optimal bounds for periodic mixtures of nearest-neighbour ferromagnetic interactions
Authors: Braides Andrea , Kreutz Leonard
Published: March 2017

We give optimal bounds for the homogenization of mixtures of two types of ferromagnetic interactions. This is done by characterizing the possible

\Gamma

-limits of the corresponding energies in a discrete-to-continuum setting. We show that for nearest-neighbour systems this characterization can be provided by a description of the possible limit Wulff shapes in terms of the percentage of one of the two types of interactions.
Strongly nonlinear Gagliardo–Nirenberg inequality in Orlicz spaces and Boyd indices
Authors: Capone Claudia , Fiorenza Alberto , Kałamajska Agnieszka
Published: March 2017

Given a N-function

A

and a continuous function

h

satisfying certain assumptions, we derive the inequality

\int_\mathbb R A(|f^{'}(x)|h(f(x)))dx\leq C_1\int_\mathbb R A\left(C_2 \sqrt[p]{ |{\cal M}f^{''}(x){\cal T}_{h,p}(f,x)| }\cdot h(f(x)) \right)dx,

with constants

C_1,C_2

independent of

f

, where

f\ge 0

belongs locally to the Sobolev space

W^{2,1}(\mathbb R)

,

f^{'}

has compact support,

p > 1

is smaller than the lower Boyd index of

A

,

{\mathcal T}_{h,p}(\cdot)

is certain nonlinear transform depending of

h

but not of

A

and

{\mathcal M}

denotes the Hardy–Littlewood maximal function. Moreover, we show that when

h\equiv 1

, then

{\mathcal M}f^{''}

can be improved by

f^{''}

. This inequality generalizes a previous result by the third author and Peszek, which was dealing with

p=2

.
Процесс направленного протекания в присутствии "синтетического" поля скорости со сжимаемостью: ренормгрупповой анализ
Authors: Antonov Nikolai Viktorovich , Gnatich Michal , Kapustin Aleksandr Sergeevich , Lučivjansky Tomas , Mizisin Lukas
Published: March 2017

Изучается процесс направленного протекания со связями (иногда называемый процессом Грибова из-за формального сходства с реджеонной теорией поля) в присутствии безвихревых флуктуаций поля скорости, коррелятор которых обладает дальнодействием. Для исследования фазового перехода из активного в абсорбированное состояние использован метод ренормализационной группы. Все расчеты проведены в однопетлевом приближении. Неподвижные точки уравнения ренормгруппы и их области устойчивости вычислены в виде разложения по трем параметрам $(\varepsilon,y,\eta)$. Рассмотрены различные режимы задачи, соответствующие модели Крейчнана быстро изменяющегося поля и "замороженного" поля скорости.
Свойства ложного вакуума как неустойчивого квантового состояния
Authors: Urbanovski K
Published: March 2017

Проанализированы свойства неустойчивых вакуумных состояний с точки зрения квантовой теории. В литературе можно встретить высказывания о том, что некоторые ложные (неустойчивые) вакуумные состояния могут выжить вплоть до времен, когда вероятность их выживания приобретает неэкспоненциальный вид. На асимптотически больших временах вероятность выживания как функция времени $t$ носит обратно-степенной характер. Показано, что в этом временном интервале энергия ложных вакуумных состояний стремится к энергии истинного вакуума по закону $1/t^2$ при $t\to\infty$. Это означает, что плотность энергии в неустойчивом вакуумном состоянии и, следовательно, космологическая постоянная $\Lambda=\Lambda(t)$ должны иметь аналогичные свойства. Вывод таков, что $\Lambda$ во вселенной с неустойчивым вакуумом должна иметь вид суммы "голой" космологической постоянной и члена типа $1/t^2$: $\Lambda(t)\equiv\Lambda_{bare}+d/t^2$ (где $\Lambda_{bare}$ - космологическая постоянная вселенной с истинным вакуумом).
Новый подход к вычислению спектра квантового пространства-времени
Authors: Starodubtsev Artem Nikolaevich
Published: March 2017

Изучается динамика массивной точечной частицы, взаимодействующей с гравитацией, в четырех пространственно-временных измерениях. Она имеет те же степени свободы, что и обычная частица: координаты по отношению к выбранному началу отсчета (наблюдателю) и канонически сопряженные импульсы. Эффект гравитации проявляется в том, что такая частица является черной дырой: на расстояниях меньше радиуса Шварцшильда от начала отсчета ее импульс становится пространственноподобным. Это происходит за счет нетривиальной структуры фазового пространства частицы: импульсное пространство имеет кривизну и эта кривизна зависит от положения в координатном пространстве. Кривизна импульсного пространства, в свою очередь, приводит к тому, что операторы координат в квантовой теории имеют нетривиальный спектр. Этот спектр не зависит от массы частицы и определяет доступные точки пространства-времени.
Electromagnetic Compatibility--Component Test Procedure--Part 42--Conducted Transient Emissions
Authors:   Electromagnetic Compatibility (EMC) Standards
Published: March 2017

This SAE Standard defines a component-level test procedure to evaluate automotive electrical and electronic components for Conducted Emissions of transients, and for other electromagnetic disturbances, along battery feed (B+) or switched ignition inputs of a Device Under Test (DUT). Test apparatus specifications outlined in this procedure were developed for components installed in the 12-V passenger cars, light trucks, 12 V heavy-duty trucks, and vehicles with 24 V systems
Tapers for Shaft Ends and Hubs for Fuel Injection Pumps
Authors:   Diesel Fuel Injection Equipment Standards Committee
Published: March 2017

This SAE Standard specifies the dimensional requirements necessary for the interchangeability of tapered shaft ends and hubs for fuel injection pumps of diesel engines.
Structural Modification for Personally Licensed Vehicles to Meet the Transportation Needs of Persons with Disabilities
Authors:   Adaptive Devices Standards Committee
Published: March 2017

The recommendations in this SAE Information Report apply to structural integrity, performance, driveability, and serviceability of personally licensed vehicles not exceeding 10 000 lb GVWR. While many of these recommendations may have application to other vehicles, such as those used in paratransit operations, the contents of this document are not directed at these types of vehicles.
Clutch Dimensions for Truck and Bus Applications
Authors:   Truck and Bus Powertrain Committee
Published: March 2017

Although not limited to, these clutches are normally used on trucks considered as Medium-Duty (Class 6 and 7), as well as Heavy-Duty (Class 8).
Physical Layer--250K bits/s, Twisted Shielded Pair
Authors:   Truck Bus Control and Communications Network Committee
Published: March 2017

These SAE Recommended Practices are intended for light- and heavy-duty vehicles on- or off-road as well as appropriate stationary applications which use vehicle derived components (e.g., generator sets). Vehicles of interest include but are not limited to: on- and off-highway trucks and their trailers; construction equipment; and agricultural equipment and implements.
Class C Application Requirement Considerations
Authors:   Vehicle Architecture For Data Communications Standards
Published: March 2017

This SAE Recommended Practice will focus on the requirements of Class C applications. The requirements for these applications are different from those required for either Class A or Class B applications. An overall example is provided for consistency of discussion.

Cancelled due to lack of interest.
Testing of Wheelchair Lifts for Entry to or Exit from a Personally Licensed Vehicle
Authors:   Adaptive Devices Standards Committee
Published: March 2017

This test procedure is for Qualification Testing of electrically powered hydraulic or mechanically operated devices which permit a person in a manual or powered wheelchair to enter or exit a personally licensed vehicle.

It establishes minimum test requirements for compliance. A lift completing the test without failure under this procedure shall be considered in compliance. The tests in Section 3 shall be done in the sequence listed.
Vehicle System Voltage—Initial Recommendations
Authors:   Vehicle  Electric  Power Supply Systems Standards Committee
Published: March 2017

This SAE Information Report is a summary of the initial recommendations of the SAE committee on Dual/Higher Voltage Vehicle Electrical Systems regarding the application of higher voltages in vehicle systems. This document does not attempt to address the technical merits of specific voltages or electrical system architectures.
On-Board Land Vehicle Mayday Reporting Interface
Authors:   ITS Council
Published: March 2017

This SAE Standard describes the interface between an on-vehicle Mayday detection, reporting system and the off-vehicle response center that will manage the response to the vehicle's call for assistance. The automatic detection and reporting by either the intelligent vehicle itself or by the intelligent roadway of a vehicle that is disabled or involved in an accident, [referred to as Automatic Mayday], is one of the key services identified by the ITS America program plan road map. This effort has been identified, as STD SAE J2313 in recent DOT-FHWA efforts to advance needed National standards.

This document primarily addresses the responsibilities of a vehicle in detecting and reporting such an event. Equipment suites on each vehicle will vary widely, as will the communications channel employed to report the incident. This document proscribes a basic methodology to uniformly incorporate whatever level of data reporting the vehicle supports (containing information about both the vehicle condition and any occupant data), and transmits this data to the response management agency in a Nationally standardized format, regardless of the transmission media used to effect the communications.

This document has been developed by the SAE ITS In-Vehicle Systems Interfaces Committee (IVSIC) in conjunction with its members, private industry, and various public safety and response agencies at both the State and Federal level. The messages developed here will form a portion of the ITS message list which is being compiled by the SAE ITS ATIS under the SAE J2354 effort and which will be used as the US submission to the ISO TC-204 effort to develop worldwide standards in this area.
Ship Systems and Equipment--Disposable Hydraulic Filter Element--115 L/Min Flow, 1.000 Mpa Collapse Pressure, Filtration Ratio = 75 At 6 and 10 Gmm
Authors:   Ship Systems - System Cleanliness and Filters Committee
Published: March 2017

This specification sheet establishes requirements for low collapse pressure elements of a specific configuration with various efficiency ratings designed and tested in accordance with SAE J2321 and the requirements of this specification sheet.
Standards for ATIS Message Sets Delivered over Reduced Bandwidth Media
Authors:   ITS Council
Published: March 2017

This SAE Standard outlines the US standard for sending Advanced Traveler Information Services (ATIS) messages over various Bandwidth Reduced Media (BRM). It specifies the “over the air” format and method for such data messages at a bit level. The methodology allows a cooperative sharing of the media’s total bandwidth with other non-ATIS data services. It allows for further expansion to other ATIS messages such as transit schedules and weather use. It uses a common directory of messages to divide out those messages which are the subject of this specification from others.

It is built upon the concept of “waveform neutrality” in that it can be hosted by a wide variety of media often found in the delivery of wireless data services (although it is also useful for wire line applications). This message set is incorporated into each medium (“host medium”) by a formatting process specific to each media. A graphical overview ofthis process is shown in Figure 1. The capacity and services available over the host media can vary considerably in terms of capacity, other services present, one way or two way use, suitability for use, and a variety of commercial aspects not considered here.

This document is divided into five primary sections. The first provides a conceptual background of various elements required to understand the message encoding process itself (chapters 4, 5, 6). The second section contains precise definitions of the messages and data elements in the messages (chapters 7, 8, 9). The third section provides implementation advice and comments for both receiver and encoder manufacturers (chapters 10, 11). The fourth section contains tables of constants used in various message encodings of the standard (chapter 12). A 5th section, contained in the appendices, is an illustrative example of the message sets implemented with real data. Finally, a set of Appendices, SAE J2369-1 provides information regarding how to implement this document on a variety of host media.
Field Test Analysis Information Report
Authors:   ITS Council
Published: March 2017

This SAE Information Report describes results of testing of the SAE J1746 ISP-Vehicle Standard for the communication of spatial data references between central sites and mobile vehicles on roads. Testing was performed by the Oak Ridge National Laboratory and its contractors, resulting in a document from which this Information Report has been extracted. Tests were performed by computer analysis and corroborated by field tests with a mobile vehicle.
Location Referencing Message Specification
Authors:   ITS Council
Published: March 2017

The LRMS is intended to provide a practical approach to standardization for location referencing within a mixed data set environment, i.e., where more than one kind of spatial data set exists, and where spatial references between these data sets must be made. Although some ITS applications in local areas may be satisfied by having one common data set— for which location references may be implemented in any number of ways— many ITS applications will have broad interoperability requirements within the nation or a region. For example, a vehicle driven from California to Florida in the U.S. should be able to receive and understand spatial references for traffic information or routing instructions throughout the trip. Similarly, information sent from a vehicle to a central site should be understood in any city regardless of the kinds of data sets in use, whether they are public or private, or how locations are referenced internally to particular data sets.

The LRMS can be applied to ITS systems involving mobile vehicles on roads, rails, and waterways. It can also be applied to location references to and from central sites to non-mobile sites such as kiosks, other central sites, or pedestrians. The broadest scope of the LRMS is therefore intermodal spatial data set interoperability at the national level and across all of ITS. Given the great variety of ITS systems, it is expected that individual LRMS profiles will generate location referencing standards for subsets of ITS applications, such as ISP→ Vehicle→ ISP, or center→ center.
Definitions and Experimental Measures Related to the Specification of Driver Visual Behavior Using Video Based Techniques
Authors:   Safety and Human Factors Standards Steering Committee
Published: March 2017

This SAE Recommended Practice defines key terms and metrics applied in the analysis of video based driver eye glance behavior. It can be applied in environments from real world trials to laboratory based driving simulator studies evaluating Transport Information and Control Systems (TICS). The procedures described in this document could also apply to more general assessments of driver visual behavior in the absence of TICS or other advanced display and control systems associated with Intelligent Transportation Systems (ITS). Driver workload studies, design of traffic control devices and roadways, modality interference from use of cell phones, mirror redesign, situational awareness, and the effects of driver stress from sleep loss and trip delays are just a few of the studies that would benefit from a standard practice for measuring visual allocation. The metrics and definitions described as follows are intended to assist development of a common source of reference for driver visual behavior data. With specification of independent variables, data collated and analyzed from this document allow comparisons to be performed across different device evaluations and experimental scenarios. It should be noted that the following definitions and measures would also apply to eye movement techniques. This document does not include the use of “head-up” displays. This document has been developed under the supervision of the SAE Safety and Human Factors Committee.
Single Wire CAN Network for Vehicle Applications
Authors:   Vehicle Architecture For Data Communications Standards
Published: March 2017

This SAE Recommended Practice defines the Physical Layer and portions of the Data Link Layer of the OSI model for data communications. In particular, this document specifies the physical layer requirements for any Carrier Sense Multiple Access/Collision Resolution (CSMA/CR) data link which operates on a single wire medium to communicate among Electronic Control Units (ECU) on road vehicles.

Requirements stated in this document will provide a minimum standard level of performance to which all compatible ECUs and media shall be designed. This will assure full serial data communication among all connected devices regardless of supplier.

This document is to be referenced by the particular vehicle OEM Component Technical Specification which describes any given ECU in which the single wire data link controller and physical layer interface is located. Primarily, the performance of the physical layer is specified in this document. ECU environmental and other requirements when provided in the Component Technical Specification, shall supercede the requirements of this document.

The intended audience includes, but is not limited to, ECU suppliers, CAN controller suppliers, CAN transceiver suppliers, component release engineers, and vehicle system engineers.
Stepwise Coastdown Methodology for Measuring Tire Rolling Resistance
Authors:   Highway Tire Committee
Published: March 2017

This SAE Recommended Practice is applicable to pneumatic Passenger Car “P” Type, Light Truck Metric, and Light Truck High Flotation tires, or similar tires approved by bodies other than Tire & Rim Association. The methodology is applicable within normal operating ranges of vertical load and inflation pressure, and for velocities between 115 km/h and 15 km/h (71 mph and 9 mph) during a relatively short duration event such as a coastdown. This procedure is applicable only to operation in the free-rolling mode at zero slip and camber angle for ambient temperatures between 20 °C and 28 °C (68 °F and 82 °F) and for surfaces with diameters of 1.2 m (48 in) diameter or greater. Details regarding the equipment, tires, and test methods used specifically for validation of this document are included in Appendix A. Two basic measurement methods covered by this document are as follows:
Welded and Cold-Drawn, SAE 1021 Carbon Steel Tubing Normalized for Bending and Flaring
Authors:   Metallic Tubing Committee
Published: March 2017

The SAE Standard covers normalized electric resistance welded, cold-drawn, single-wall, SAE 1021 carbon steel pressure tubing intended for use as pressure lines and in other applications requiring tubing of a quality suitable for bending, flaring, forming, and brazing.

The grade of material produced to this specification is higher in carbon content and manganese content than the grade of material specified in SAE J525. The material produced to this specification is intended to service higher pressure applications than like sizes of SAE J525. Due to the higher carbon and manganese content, however, the forming characteristics of the finished tube is diminished somewhat when compared to SAE J525. Special attention to the overall forming requirements of the finished assembly should be taken into consideration when utilizing material produced to this specification.
Road Vehicles-Brake Linings-Compressibility Test Procedure
Authors:   Brake Linings Standards Committee
Published: March 2017

This SAE Standard specifies a method for testing and measuring the compressibility of friction materials and disc brake pad assemblies to be used in road vehicles. This SAE test method is consistent in intent with ISO 6310.
Plug-In Relay Test Methods
Authors:   Circuit Protection and Switch Device Committee
Published: March 2017

This SAE Standard covers standard test methods for environmental, mechanical, and electrical testing of plug-in relays used in surface vehicle electrical systems.
Fuel Injection Equipment Nomenclature
Authors:   Diesel Fuel Injection Equipment Standards Committee
Published: March 2017

This SAE Standard establishes a vocabulary and definitions relating to the components used in fuel injection systems for compression ignition (diesel) engines.

Definitions are separated into six sections by topic as follows:

Section 3— Fuel Injection Pumps

Section 4— Fuel Injectors

Section 5— Unit Injectors

Section 6— Governors

Section 7— Timing Devices

Section 8— High Pressure Pipes and Connections

NOTE— When the word "fuel" is used in the terms listed it may be omitted providing there can be no misunderstanding.
STANDARD FOR IN-TANK ELECTRIC FUEL PUMPS
Authors:   USCAR
Published: March 2017

This standard covers the operational characteristics, environment, durability procedures, and test procedures for in-tank electric fuel pumps for automotive gasoline applications. Specific performance and test criteria used in conjunction with this procedure are specified on the pump drawing. Particular sections of this document may be required for all applications. This standard is intended to evaluate specific characteristics as a supplement to normal material inspections, dimensional checking, and in-process controls, and should in no way adversely influence other inspection operations.
Atmospheric aerosol compositions over the South China Sea: temporal variability and source apportionment
Authors: Xiao Hong-Wei , Xiao Hua-Yun , Luo Li , Shen Chun-Yan , Long Ai-Min , Chen Lin , Long Zhen-Hua , Li Da-Ning
Published: March 2017

Abstract. In order to evaluate impacts of different source emission on marine atmospheric particles over the South China Sea (SCS), major inorganic ionic concentrations (Na+, Cl−, SO42−, Ca2+, Mg2+, K+, NH4+ and NO3−) were determined in total suspended particulates (TSPs) at Yongxing Island, from March 2014 to February 2015. The annual average concentration of TSPs was 89.6 ± 68.0 µg m−3, with 114.7 ± 82.1, 60.4 ± 27.0 and 59.5 ± 25.6 µg m−3 in cool, warm and transition seasons, respectively. Cl− had the highest concentration, with an annual average of 7.73 ± 5.99 µg m−3, followed by SO42− (5.54 ± 3.65 µg m−3), Na+ (4.00 ± 1.88 µg m−3), Ca2+ (2.15 ± 1.54 µg m−3), NO3− (1.95 ± 1.34 µg m−3), Mg2+ (0.44 ± 0.33 µg m−3), K+ (0.33 ± 0.22 µg m−3) and NH4+ (0.07 ± 0.07 µg m−3). Concentrations of TSPs and the major ions showed seasonal variations, which were higher in the cool season and lower in the warm and transition seasons. Factors of influence were wind speed, temperature, relatively humidity, rain and air mass source region. Back trajectories, concentration-weighted trajectories (CWTs), and positive matrix factorization (PMF) of chemical compositions were analyzed for source apportionment, source contribution and spatiotemporal variation of major ions. Back trajectories and CWTs showed that air masses at Yongxing Island were mainly from the northeast, southwest and southeast in the cool, warm and transition seasons, respectively. The PMF results showed that 77.4 % of Na+ and 99.3 % of Cl− were from sea salt; 60.5 % of NH4+ was from oceanic emission. Anthropogenic sources were very important for atmospheric aerosols over the island. Secondary inorganic aerosol of SO2 and NOx from fossil fuel combustion (especially coal in Chinese coastal regions) was the dominant source of NO3− (69.5 %) and SO42− (57.5 %).
CCl4 distribution derived from MIPAS ESA V7 data: validation, trend and lifetime estimation
Authors: Valeri Massimo , Barbara Flavio , Boone Chris , Ceccherini Simone , Gai Marco , Maucher Guido , Raspollini Piera , Ridolfi Marco , Sgheri Luca , Wetzel Gerald , Zoppetti Nicola
Published: March 2017

Abstract. Atmospheric emissions of Carbon tetrachloride CCl4 are regulated by the Montreal Protocol due to its role as a strong ozone-depleting substance. The molecule has been the subject of recent increased interest as a consequence of the so called ``mystery of CCl4,'' the discrepancy between atmospheric observations and reported production and consumption. Surface measurements of CCl4 atmospheric concentrations have declined at a rate almost three times smaller than its lifetime-limited rate, suggesting persistent atmospheric emissions despite the ban. In this paper, we study CCl4 vertical and zonal distributions in the upper troposphere and lower stratosphere (including the photolytic loss region, 70–20 hPa), its trend, and its stratospheric lifetime using measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), which operated onboard the ENVISAT satellite from 2002 to 2012. Specifically, we use the MIPAS data product generated with Version 7 of the Level 2 algorithm operated by the European Space Agency. The CCl4 zonal means show features typical of long-lived species of anthropogenic origin that are destroyed primarily in the stratosphere, with larger quantities in the troposphere and a monotonic decrease with increasing altitude in the stratosphere. In the troposphere, the largest concentrations are observed at the latitudes of major industrial countries (20/50°N). The good agreement we find between MIPAS CCl4 and independent measurements from other satellite and balloon-borne remote sounders proves the reliability of the MIPAS dataset. CCl4 trends are calculated as a function of both latitude and altitude. Negative trends are found at all latitudes in the upper-troposphere / lower-stratosphere region, apart from a region in the Southern mid-latitudes between 50 and 10 hPa where the trend is positive. At the lowest altitudes sounded by MIPAS, we find trends consistent with those determined on the basis of long-term ground-based measurements. For higher altitudes, the trend shows a pronounced asymmetry between Northern and Southern Hemispheres, and the magnitude of the decline rate increases with altitude. At 50 hPa the decline is about 30–35 %/decade, close to the lifetime-limited trend. We use a simplified model assuming tracer-tracer linear correlations to determine CCl4 lifetime in the lower stratosphere. The calculation provides a global average lifetime of 46(38–60) years considering CFC-11 as the reference tracer. This value is consistent with the most recent literature result of 44(36–58) years.
Can terrestrial laser scanners (TLSs) and hemispherical photographs predict tropical dry forest succession with liana abundance?
Authors: Sánchez-Azofeifa Gerardo Arturo , Guzmán-Quesada J. Antonio , Vega-Araya Mauricio , Campos-Vargas Carlos , Durán Sandra Milena , D'Souza Nikhil , Gianoli Thomas , Portillo-Quintero Carlos , Sharp Iain
Published: March 2017

Abstract. Tropical dry forests (TDFs) are ecosystems with long drought periods, a mean temperature of 25 °C, a mean annual precipitation that ranges from 900 to 2000 mm, and that possess a high abundance of deciduous species (trees and lianas). What remains of the original extent of TDFs in the Americas remains highly fragmented and at different levels of ecological succession. It is estimated that one of the main fingerprints left by global environmental and climate change in tropical environments is an increase in liana coverage. Lianas are non-structural elements of the forest canopy that eventually kill their host trees. In this paper we evaluate the use of a terrestrial laser scanner (TLS) in combination with hemispherical photographs (HPs) to characterize changes in forest structure as a function of ecological succession and liana abundance. We deployed a TLS and HP system in 28 plots throughout secondary forests of different ages and with different levels of liana abundance. Using a canonical correlation analysis (CCA), we addressed how the VEGNET, a terrestrial laser scanner, and HPs could predict TDF structure. Likewise, using univariate analyses of correlations, we show how the liana abundance could affect the prediction of the forest structure. Our results suggest that TLSs and HPs can predict the differences in the forest structure at different successional stages but that these differences disappear as liana abundance increases. Therefore, in well known ecosystems such as the tropical dry forest of Costa Rica, these biases of prediction could be considered as structural effects of liana presence. This research contributes to the understanding of the potential effects of lianas in secondary dry forests and highlights the role of TLSs combined with HPs in monitoring structural changes in secondary TDFs.
Methane and carbon dioxide fluxes over a lake: comparison between eddy covariance, floating chambers and boundary layer method
Authors: Erkkilä Kukka-Maaria , Mammarella Ivan , Bastviken David , Biermann Tobias , Heiskanen Jouni J. , Lindroth Anders , Peltola Olli , Rantakari Miitta , Vesala Timo , Ojala Anne
Published: March 2017

Abstract. Freshwaters bring a notable contribution to the global carbon budget by emitting both carbon dioxide (CO2) and methane (CH4) to the atmosphere. Global estimates of freshwater emissions traditionally use a wind speed based gas transfer coefficient, kCC, for calculating diffusive flux with the boundary layer method (BLM). We compared CH4 and CO2 fluxes from BLM with kCC and two other gas transfer coefficients (kTE and kHE), that include the effects of water-side cooling to the gas transfer besides shear-induced turbulence, with simultaneous eddy covariance (EC) and floating chamber (FC) fluxes during a 16-day measurement campaign in September 2014 at Lake Kuivajärvi in Finland. The measurements included both lake stratification and water column mixing periods. A clear increase in both CH4 and CO2 fluxes was detected right after turnover started. Results show that kCC model underestimates both CH4 and CO2 fluxes compared to EC measurements and the more recent model kTE gives the best fit with EC fluxes. In the stratified period, kHE and kCC used in BLM calculation have similar diurnal variation for CO2 flux, while kTE gives an opposite diurnal cycle. This is probably due to water friction velocity derived from EC measurements in kTE model instead of direct waterside turbulence measurements in this study. In the mixing period all models agree well with each other on diurnal variation for both CH4 and CO2. We highly recommend using up to date gas transfer models, instead of kCC, for better flux estimates. FC measurements did not detect spatial variation in either CH4 or CO2 flux over Lake Kuivajärvi. EC measurements, on the other hand, did not show any spatial variation in CH4 fluxes, but a clear difference between CO2 fluxes from shallower and deeper areas. Fluxes measured with FC were systematically higher than EC fluxes, partly due to deficiencies in the EC method.
Ground surface temperature reconstruction for the last 500 years obtained from permafrost temperatures observed in the Stelvio Share borehole, Italian Alps
Authors: Guglielmin Mauro , Donatelli Marco , Semplice Matteo , Serra Capizzano Stefano
Published: March 2017

Abstract. The general pattern of ground surface temperatures (GST) reconstructed from the permafrost Stelvio Share Borehole (SSB) for the last 500 years are similar to the mean annual air temperature (MAAT) reconstructions for the European Alps. The main difference with respect to MAAT reconstructions relates to post Little Ice Age (LIA) events. Between 1940 and 1989, SSB data indicate a 0.9 °C cooling. Subsequently, a rapid and abrupt GST warming (more than 0.8 °C per decade) was recorded between 1990 and 2011. This warming is of the same magnitude as the increase of MAAT between 1990 and 2000 recorded in central Europe and roughly double the MAAT in the Alps.
Flexible parameter-sparse global temperature time-profiles that
stabilise at 1.5 °C and 2.0 °C
Authors: Huntingford Chris , Yang Hui , Harper Anna , Cox Peter M. , Gedney Nic , Burke Eleanor J. , Lowe Jason A. , Hayman Garry , Collins Bill J. , Smith Stephen M. , Comyn-Platt Ed
Published: March 2017

Abstract. The UNFCCC Paris climate meeting of December 2015 committed to holding the rise in global average temperature to below 2.0 °C above pre-industrial levels. It also committed to pursue efforts to limit warming to 1.5 °C. This leads to two key questions. First, what extent of reductions in emissions will achieve either target? Second, given emissions cuts to achieve the lower target may be especially difficult to achieve, then what is the benefit from reduced climate impacts by keeping warming at or below 1.5 °C? To provide answers climate model simulations need to follow trajectories consistent with these global temperature limits. This implies operating models in an invertible form, to make model-specific estimates of greenhouse gas (GHG) concentration pathways consistent with prescribed temperature profiles. Further inversion derives related emissions pathways for these concentrations. For this to happen, and to enable climate research centres to compare GHG concentrations and emissions estimates, common temperature trajectory scenarios are required. Here we define algebraic curves which asymptote to a stabilised limit, while also matching the magnitude and gradient of recent warming levels. The curves are deliberately parameter-sparse, needing prescription of just two parameters plus the final temperature. Yet despite this simplicity they can allow for temperature overshoot and for generational changes where more effort occurs to decelerate warming change by future generations. The curves capture temperature profiles from the existing rcp2.6 scenario model projections, which have warming amounts towards the lower levels of those that society is discussing.
On the coupled unsaturated–saturated flow process induced by vertical, horizontal, and slant wells in unconfined aquifers
Authors: Liang Xiuyu , Zhan Hongbin , Zhang You-Kuan , Liu Jin
Published: March 2017

Abstract. Conventional models of pumping tests in unconfined aquifers often neglect the unsaturated flow process. This study concerns the coupled unsaturated–saturated flow process induced by vertical, horizontal, and slant wells positioned in an unconfined aquifer. A mathematical model is established with special consideration of the coupled unsaturated–saturated flow process and the well orientation. Groundwater flow in the saturated zone is described by a three-dimensional governing equation and a linearized three-dimensional Richards' equation in the unsaturated zone. A solution in the Laplace domain is derived by the Laplace–finite-Fourier-transform and the method of separation of variables, and the semi-analytical solutions are obtained using a numerical inverse Laplace method. The solution is verified by a finite-element numerical model. It is found that the effects of the unsaturated zone on the drawdown of a pumping test exist at any angle of inclination of the pumping well, and this impact is more significant in the case of a horizontal well. The effects of the unsaturated zone on the drawdown are independent of the length of the horizontal well screen. The vertical well leads to the largest water volume drained from the unsaturated zone (W) during the early pumping time, and the effects of the well orientation on W values become insignificant at the later time. The screen length of the horizontal well does not affect W for the whole pumping period. The proposed solutions are useful for the parameter identification of pumping tests with a general well orientation (vertical, horizontal, and slant) in unconfined aquifers affected from above by the unsaturated flow process.
Extending flood forecasting lead time in a large watershed by coupling WRF QPF with a distributed hydrological model
Authors: Li Ji , Chen Yangbo , Wang Huanyu , Qin Jianming , Li Jie , Chiao Sen
Published: March 2017

Abstract. Long lead time flood forecasting is very important for large watershed flood mitigation as it provides more time for flood warning and emergency responses. The latest numerical weather forecast model could provide 1–15-day quantitative precipitation forecasting products in grid format, and by coupling this product with a distributed hydrological model could produce long lead time watershed flood forecasting products. This paper studied the feasibility of coupling the Liuxihe model with the Weather Research and Forecasting quantitative precipitation forecast (WRF QPF) for large watershed flood forecasting in southern China. The QPF of WRF products has three lead times, including 24, 48 and 72 h, with the grid resolution being 20 km  × 20 km. The Liuxihe model is set up with freely downloaded terrain property; the model parameters were previously optimized with rain gauge observed precipitation, and re-optimized with the WRF QPF. Results show that the WRF QPF has bias with the rain gauge precipitation, and a post-processing method is proposed to post-process the WRF QPF products, which improves the flood forecasting capability. With model parameter re-optimization, the model's performance improves also. This suggests that the model parameters be optimized with QPF, not the rain gauge precipitation. With the increasing of lead time, the accuracy of the WRF QPF decreases, as does the flood forecasting capability. Flood forecasting products produced by coupling the Liuxihe model with the WRF QPF provide a good reference for large watershed flood warning due to its long lead time and rational results.
Temporal and spatial evaluation of satellite-based rainfall estimates across the complex topographical and climatic gradients of Chile
Authors: Zambrano-Bigiarini Mauricio , Nauditt Alexandra , Birkel Christian , Verbist Koen , Ribbe Lars
Published: March 2017

Abstract. Accurate representation of the real spatio-temporal variability of catchment rainfall inputs is currently severely limited. Moreover, spatially interpolated catchment precipitation is subject to large uncertainties, particularly in developing countries and regions which are difficult to access. Recently, satellite-based rainfall estimates (SREs) provide an unprecedented opportunity for a wide range of hydrological applications, from water resources modelling to monitoring of extreme events such as droughts and floods.This study attempts to exhaustively evaluate – for the first time – the suitability of seven state-of-the-art SRE products (TMPA 3B42v7, CHIRPSv2, CMORPH, PERSIANN-CDR, PERSIAN-CCS-Adj, MSWEPv1.1, and PGFv3) over the complex topography and diverse climatic gradients of Chile. Different temporal scales (daily, monthly, seasonal, annual) are used in a point-to-pixel comparison between precipitation time series measured at 366 stations (from sea level to 4600 m a.s.l. in the Andean Plateau) and the corresponding grid cell of each SRE (rescaled to a 0.25° grid if necessary). The modified Kling–Gupta efficiency was used to identify possible sources of systematic errors in each SRE. In addition, five categorical indices (PC, POD, FAR, ETS, fBIAS) were used to assess the ability of each SRE to correctly identify different precipitation intensities.Results revealed that most SRE products performed better for the humid South (36.4–43.7° S) and Central Chile (32.18–36.4° S), in particular at low- and mid-elevation zones (0–1000 m a.s.l.) compared to the arid northern regions and the Far South. Seasonally, all products performed best during the wet seasons (autumn and winter; MAM–JJA) compared to summer (DJF) and spring (SON). In addition, all SREs were able to correctly identify the occurrence of no-rain events, but they presented a low skill in classifying precipitation intensities during rainy days. Overall, PGFv3 exhibited the best performance everywhere and for all timescales, which can be clearly attributed to its bias-correction procedure using 217 stations from Chile. Good results were also obtained by the research products CHIRPSv2, TMPA 3B42v7 and MSWEPv1.1, while CMORPH, PERSIANN-CDR, and the real-time PERSIANN-CCS-Adj were less skillful in representing observed rainfall. While PGFv3 (currently available up to 2010) might be used in Chile for historical analyses and calibration of hydrological models, the high spatial resolution, low latency and long data records of CHIRPS and TMPA 3B42v7 (in transition to IMERG) show promising potential to be used in meteorological studies and water resource assessments. We finally conclude that despite improvements of most SRE products, a site-specific assessment is still needed before any use in catchment-scale hydrological studies.