ALBERT

Description: Invertebrates in estuaries could be at a greater risk of parasitism as climate change causes sea levels to rise. A new paper published 8 December in Proceedings of the National Academy of Sciences of the United States of America (doi:10.1073/pnas.1416747111) describes how rapid sea level rise in the Holocene affected the population of parasitic flatworms called trematodes.

Description: Since 2007 a large decline in Arctic sea ice has been observed. The large-scale atmospheric circulation response to this decline is investigated in ERA-Interim reanalyses and HadGEM3 climate model experiments. In winter, post-2007 observed circulation anomalies over the Arctic, North Atlantic and Eurasia are small compared to interannual variability. In summer, the post-2007 observed circulation is dominated by an anticyclonic anomaly over Greenland which has a large signal-to-noise ratio. Climate model experiments driven by observed SST and sea ice anomalies are able to capture the summertime pattern of observed circulation anomalies, although the magnitude is a third of that observed. The experiments suggest warm SSTs and reduced sea ice in the Labrador Sea lead to warm temperature anomalies in lower troposphere which weaken the westerlies over North America through thermal wind balance. The experiments also capture cyclonic anomalies over north-western Europe, which are consistent with downstream Rossby wave propagation.

Description: Herein, we report on the crystal structures of Nb 2 AlC and TiNbAlC—actual composition (Ti 0.45 ,Nb 0.55 ) 2 AlC—compounds determined from Rietveld analysis of neutron diffraction patterns in the 300–1173 K temperature range. The average linear thermal expansion coefficients of a Nb 2 AlC sample in the a and c directions are, respectively, 7.9(5) × 10 −6 and 7.7(5) × 10 −6  K −1 on one neutron diffractometer and 7.3(3) × 10 −6 and 7.0(2) × 10 −6  K −1 on a second diffractometer. The respective values for the (Ti 0.45 ,Nb 0.55 ) 2 AlC composition—only tested on one diffractometer—are 8.5(3) × 10 −6 and 7.5(5) × 10 −6  K −1 . These values are relatively low compared to other MAX phases. Like other MAX phases, however, the atomic displacement parameters (APDs) show that the Al atoms vibrate with higher amplitudes than the Ti and C atoms, and more along the basal planes than normal to them. When the predictions of the APDs obtained from density functional theory are compared to the experimental results, good quantitative agreement is found for the Al atoms. In case of the Nb and C atoms, the agreement was more qualitative.

Description: In this study, lithium disilicate (LS 2 ) glass samples with different particle sizes ranging from less than 105 to 850 μm were prepared. These specimens were inserted in a Pt-Rh DSC crucible and heated to 850°C at different rates (ϕ = 0.5–30 K/min) to identify their crystallization peaks. The activation energies for the overall crystallization ( E ) and the Avrami coefficient ( n ) were evaluated using different nonisothermal models. Specifically, n was evaluated using the Augis–Benett model and the Ozawa method, and E was evaluated using the Kissinger and Ligero methods. As expected, the coarse particles mainly crystallized in the volume, while surface crystallization was predominant in the samples with particle sizes of less than 350 μm. This result was confirmed through SEM analysis of the double stage heat-treated samples. In contrast with previous studies, our results demonstrated that the activation energy decreased as the particle size increased. In addition, no clear correlation between the peak intensity (δ T p ) and the particle size was observed.

Description: Stratospheric Sounding Units (SSU) on the NOAA polar orbiting satellites measured infrared radiances in the 15 micron CO 2 band between late 1978 and mid-2006. From these radiances a time series of layer mean stratospheric temperatures has been derived by several groups. Discrepancies in these temperature analyses have been highlighted recently and efforts are now underway to resolve the differences between them. This paper is the Met Office response summarising the issues to be resolved in creating a climate data record from the different SSUs, including corrections for radiometric, spectroscopic and tidal differences. Calibration issues identified include the SSU space view anomaly and radiometric anomalies in the NOAA-9 observations. The spectroscopic correction required for changing pressures in the pressure modulator cells is also outlined. The most important correction for the time series is for the solar diurnal and semi-diurnal tides as the satellite overpass local times change. Comparisons with other stratospheric temperature trend analyses are made and the reasons for the differences discussed. The time series presented here show sustained drops in stratospheric temperatures at all levels after the El Chichon and Pinatubo eruptions but only small trends to lower temperatures between eruptions.

Description: A high-order global shallow water model on Yin-Yang grid has been developed by using the multi-moment constrained finite volume (MCV) method. Different from the traditional finite volume method, more degrees of freedom (DOFs) which are the values at the solution points within each mesh element are defined and updated in time. The time evolution equations for these point values are derived from a set constraint conditions in terms of the so-called multi-moment quantities, such as the point value (PV), the volume-integrated average (VIA) and derivative (DV). Different moments use different forms of equations which are all consistent with the shallow water equations, among which the VIA moment is computed from a finite volume formulation of flux form that guarantees the rigorous numerical conservation. A fourth-order formulation is devised with the third-order reconstruction built over each element using the DOFs locally available. A simple and orthogonal overset grid, the Yin-Yang grid, is used to represent the spherical geometry with quasi-uniform grid spacing. The resulting global shallow water model is attractive in algorithmic simplicity and computational efficiency. The model has been validated by widely used benchmark tests. The numerical results of the present model are competitive to most existing advanced models.

Description: About an hour and a half before the launch of the Orbital Sciences Corporation's Antares rocket and Cygnus cargo spacecraft at 6:22 p.m. on 28 October, Jeff Goldstein arrived at his vantage point on Arbuckle Neck Road in Assawoman, Va. It was just 1.5 miles from launchpad 0A at NASA's Wallops Flight Facility. Goldstein, director of the National Center for Earth and Space Science Education (NCESSE) had come with about 35 elementary school through college students, as well as some parents, teachers, and school administrators, to watch the liftoff that would deliver the students' microgravity experiments to the International Space Station (ISS).

Description: Americans are very worried about the threat of natural disasters—but don't seem to be prepared for one. This conclusion comes from Chapman University's recent Survey on American Fears, released on 21 October. The survey asked 1500 Americans to rank how worried they were about several types of natural disasters and then how prepared they were for each.

Description: Microbial communities in thawing permafrost contribute a significant amount to atmospheric methane, a greenhouse gas many times more potent than carbon dioxide. A new paper published in Nature on 23 October describes how a newly discovered microbe— Methanoflorens stordalenmirensis —adds another layer to the complicated relationship between the world's permafrost fields and greenhouse gas (GHG) emissions.

Description: Crowdsourcing—“the act of taking a job traditionally performed by a designated agent [expert] and outsourcing it to an undefined, generally large group of people” [ Howe, 2009]—has fundamentally changed and enhanced the collection and dissemination of data. Crowdsourcing has proven effective for rapid data collection, especially where in-depth knowledge of a topic or discipline is not a necessity.

Description: I am a counter by nature. I count things as an effective way to occupy my mind. How many people are in this room? How many are women? How many are wearing glasses? How many people are using a Mac versus a PC?

Description: Ethics education is an increasingly important component of the pre-professional training of geoscientists. Geoethics encompasses the values and professional standards required of geoscientists to work responsibly in any geoscience profession and in service to society. Funding agencies (e.g., the National Science Foundation, the National Institutes of Health) require training of graduate students in the responsible conduct of research; employers are increasingly expecting their workers to have basic training in ethics; and the public demands the highest standards of ethical conduct by scientists. However, there is currently no formal course of instruction in ethics in the geoscience curriculum, and few faculty members have the experience, resources, and sometimes willingness required to teach ethics as a component of their geoscience courses.

Description: U.S. hydrocarbon production is on the rise, meaning that transporting hydrocarbons—whether by pipelines, trucks, or trains—is as well. However, increasing environmental concerns, mixed with other issues such as energy independence and landowner rights, is making this transportation a hot-button issue.

Description: Lava from Iceland's Bardarbunga volcano, which began erupting on 29 August, now covers 60 square kilometers of the Holuhraun lava field. Scientists have arrived in droves to study the ongoing fissure eruptions.

Description: In the early years of the 20th century, physicist Bernard Brunhes, then director of the Geophysical Observatory of Puy de Dôme (now Observatoire de Physique du Globe de Clermont), measured for the first time reverse magnetization in samples from a basaltic lava flow and from the underlying backed argillaceous sediments from the village of Pontfarein (now Pont Farin) in the Cantal volcanic district (Auvergne, France).

Description: During the latter half of the Cenozoic, starting during the Pliocene, the eastern equatorial Pacific (EEP) underwent a change from warm, wet climate conditions—which scientists refer to as “permanent El Niño”—to more moderate conditions like those observed today. Although scientists can track this change using marine proxy records, they are still puzzled as to why the sudden shift occurred.

Description: Scientists who study the physics of inland and coastal water bodies met in Trento, Italy in July for the 17th in a series of workshops that seek to expand cooperation with researchers in related fields. The workshops aim to facilitate the dialogue among physical limnologists, modelers, and colleagues from other disciplines, such as biologists, chemists, and engineers. This year's workshop was attended by 47 participants from 17 different countries.

Description: Saturn's magnetosphere exhibits phenomena with 10.7-hour periodicity that scientists do not fully understand. One proposed explanation is that twin vortices in the upper atmosphere at Saturn's north and south poles generate currents that drive the magnetosphere periodicity.

Description: On 9 December a dynamic, new, broadly inclusive, and freely accessible Earth and space science news website will launch: Eos.org. This new site is inspired by AGU's vision to galvanize our community of Earth and space scientists to collaboratively advance and communicate our science.

Description: The motion of the Earth's mantle is controlled in part by how mantle minerals respond to changes in temperature and pressure. The chemical and physical shifts that minerals undergo as they are heated and squeezed cause some to sink down toward the core and others to rise up toward the surface. This buoyant pressure and gravitational sinking, in turn, affect the convection of the mantle and the large-scale cycling of the Earth.

Description: Because the Earth's population is slated to hit 9 billion in the next century, food scarcity has become an increasingly important topic of study. Food availability is widely examined, but D'Odorico et al. point out that reliance on trade to distribute food has not been sufficiently quantified.

Description: As a glacier slides slowly into the sea, buoyancy eventually trumps gravity, and the sheet of ice floats. The place where the ice starts leaving the ground is called the grounding line, and this line can shift as the mass of the glacier shifts with precipitation or climate. Studying the movement of the grounding line through time helps scientists determine the stability of the glacier and its mass budget—the balance of how much mass the glacier is gaining or losing.

Description: The Edmond M. Dewan Young Scientist Scholarship fund has reached its goal of $25,000. Those who donated to the fund share AGU's mission in taking an active role in educating and nurturing the next generation of scientists and ensuring a sustainable future for society. Thanks to the generosity of more than 100 members of the AGU and science community, a deserving graduate student of atmospheric or space physics will receive financial assistance to further his or her research and advance his or her research and future career.

Description: Throughout the western United States, scientists have noticed that warming has reduced snow accumulation and led to earlier snowmelt, a change that could have dire consequences for the region's ecology and industries. Specifically, previous research has found that the rain-snow transition zone—the area where precipitation is dominated by rain versus snow in the winter—has shifted significantly in the past few decades.

Description: Coastal Oregon is home to a number of slow, recurrent landslides. During bouts of heavy rain, water gets into the soil, reducing friction and causing the ground to slip. Often, these landslides creep along at a barely perceptible rate—less than a centimeter per day. Yet the landslides are a lurking threat, as past events that have damaged infrastructure and cut communities off for months at a time have demonstrated.

Description: Surface ice on oceans and lakes can cause major problems onshore and offshore. Specifically, surface waves interacting with ice can create hazardous conditions for cargo ships, damage coastal structures, and carry important nutrients away from the shore.

Description: Linear instability of warm core eddies of constant potential vorticity (PV) is studied in a two layer, finite depth, shallow water ocean. The basic state flow in the constant PV eddy that obeys the gradient balance cannot be described by explicit expressions and can only be solved numerically. The various cases of gradient balance are classified by constructing a canonical formulation that relates any PV value to a value of the angular velocity that has to prevail near the center of the constant PV eddy. The growth-rates of perturbations imposed on the basic state are calculated for a variety of values of the (constant) PV and the depth of the surrounding ocean. The growth-rates i.e. the eigenvalues are calculated numerically by employing a shooting to fitting point method that guarantees that the corresponding eigenfunctions are regular at all singular points. The maximal growth-rates are contoured as functions of PV and ocean depth for azimuthal wavenumber 2 and 3 and the maximum of these growth-rates is of the order of 1 day which is similar to that of a solidly rotating eddy. However, the range angular velocity and ocean depth where the constant PV eddy is unstable is greatly reduced compared to that of a solidly rotating eddy. The instabilities found here are classified in terms of wave-wave interactions by comparing our results in each PV value with the known instabilities of the solidly rotating eddy with the same angular velocity. In the constant PV eddy the Baroclinic instability is filtered out and the range of angular velocity where the Hybrid instability exists is significantly reduced. All instabilities decay monotonically with the increase in ocean depth.

Description: In this letter, 2-μm Pb 0.97 La 0.02 (Zr 0.75 Sn 0.18 Ti 0.07 )O 3 antiferroelectric thick film with tetragonal structure was prepared. The effects of operating electric field, temperature, and frequency on the thermal–electrical energy harvesting capacity of the film were studied by using the Olsen cycle. The results demonstrated that giant energy harvesting effect could be realized in the antiferroelectric thick film. The maximum harvestable energy density per cycle of the film was about 7.8 J/cm 3 at 1 kHz, which was the largest reported value to date. The corresponding energy harvesting efficiency was 0.53%. Moreover, the film had a low leakage current density (about 7.3 × 10 −7 and 3.9 × 10 −5  A/cm 2 at 25 and 200°C, respectively), which was favorable for its application in the devices of the thermal–electrical energy harvesting.

Description: Discharged energy properties of PbO–SrO–Na 2 O–Nb 2 O 5 –SiO 2 glass-ceramics with crystallization time from 1 to 1000 min were investigated by measuring their hysteresis loops (described as quasi-static measuring method) and pulse-discharge current-time curves (described as dynamic measuring method). The results show the same trend for both measuring methods: With the increment of crystallization time, the discharged energy density increases gradually, while the energy efficiency decreases. The highest energy efficiencies were obtained in the sample with crystallization time of 1 min, which are 96.3% and 82.4%, corresponding quasi-static and dynamic measurement, respectively. The reduction of energy efficiency with crystallization time is attributed to combined effect of ferroelectric polarization and interfacial polarization, and part of the corresponding energy could not release in the pulse-discharge process.

Description: As part of the Amazon Web Services Hack-A-Thon, this year's AGU Fall Meeting attendees will be challenged to create an idea for a Web product based on climate change data for individual cities.

Description: The rate of ocean acidification in coral reefs outpaces the rise in carbon dioxide (CO 2 ) in Earth's atmosphere, indicating that anthropogenic carbon emissions alone are not to blame for the threat to coral reefs, a new study shows.

Description: New lead-free perovskite solid solution ceramics of (1  − x )( Bi 1/2 Na 1/2 ) TiO 3 – x Ba ( Ni 1/2 Nb 1/2 ) O 3 [(1− x )BNT– x BNN, x  =   0.02–0.06) were prepared and their dielectric, ferroelectric, piezoelectric, and electromechanical properties were investigated as a function of the BNN content. The X-ray diffraction results indicated that the addition of BNN has induced a morphotropic phase transformation from rhombohedral to pseudocubic symmetry approximately at x  =   0.045, accompanying an evolution of dielectric relaxor behavior as characterized by enhanced dielectric diffuseness and frequency dispersion. In the proximity of the ferroelectric rhombohedral and pseudocubic phase coexistence zone, the x  =   0.045 ceramics exhibited optimal piezoelectric and electromechanical coupling properties of d 33 ~121 pC/N and k p ~0.27 owing to decreased energy barriers for polarization switching. However, further addition of BNN could cause a decrease in freezing temperatures of polar nanoregions till the coexistence of nonergodic and ergodic relaxor phases occurred near room temperature, especially for the x  =   0.05 sample which has negligible negative strains and thus show the maximum electrostrain of 0.3% under an external electric field of 7 kV/mm, but almost vanished piezoelectric properties. This was attributed to the fact that the induced long-range ferroelectric order could reversibly switch back to its original ergodic state upon removal of external electric fields.

Description: Light transmission in polycrystalline magnesium fluoride was studied as a function of the mean grain size at different wavelengths. The mean grain size was varied by annealing hot-pressed billets in argon atmosphere at temperatures ranging from 600°C to 800°C for 1 h. The grain-size and grain-orientation distributions were characterized by electron back scatter diffraction. The scattering coefficients were calculated from the in-line transmittance measured at various wavelengths. The scattering coefficient of polycrystalline magnesium fluoride increased linearly with the mean grain size and inversely with the square of the wavelength of light. It is shown that these trends are consistent with theoretical models based on both a limiting form of the Raleigh–Gans–Debye (RGD) theory of particle scattering and light retardation theories that take refractive index variations along the light path. Quantitative predictions of the theories are, however, subject to uncertainly due to the restrictive assumptions made in the theories and difficulties in representing the microstructure in the theoretical models. In particular, grain-size distribution has a significant influence on the scattering coefficient calculated using particle scattering models.

Description: Determining the absolute chronology of ceramic artifacts has significant implications for archeological and historical research. Wilson, Hall et al . recently suggested a new technique for direct absolute dating of archeological ceramics based on a moisture-induced chemical reaction, called rehydroxylation (RHX) dating. RHX dating proceeds by measuring the mass of chemically combined water in the ceramics in the form of OH hydroxyls, and the mass gain rate at the Effective Lifetime Temperature (ELT) that the ceramics experienced over its lifetime. To date, ELT determinations have been based on estimates of the ceramic's lifetime temperature history; taking into account weather and climate data and the depth at which the artifact was found. The uncertainty in determining the ELT can be a major component of the overall dating uncertainty. Here, we propose an alternative method which relies minimally on weather and climate data, and provides more precise determinations of the ELT and the ceramic age . The proposed method (SAS: Same Age Samples) involves a minimum of four measurements of the RHX mass gain rate constant for two ceramic samples of the same age at two temperatures. We show via simulations that the proposed SAS method can determine the ELT with a precision of 0.2 K which is comparable to the best ELT determination based on lifetime temperature history, and also comparable to available microbalance temperature resolutions of around 0.1 K. The corresponding percent age error is then 1.4%, or 43 yr for a 3000-yr-old ceramic. The proposed SAS method should be tested with ceramic samples of different ages, whose ELT are well-known.

Description: Glasses in the Na 2 O–CaO–SrO–ZnO–SiO 2 system have previously been investigated for suitability as a reagent in Al-free glass polyalkenoate cements (GPCs). These materials have many properties that offer potential in orthopedics. However, their applicability has been limited, to date, because of their poor strength. This study was undertaken with the aim of increasing the mechanical properties of a series of these Zn-based GPC glasses by doping with nitrogen to give overall compositions of: 10Na 2 O–10CaO–20SrO–20ZnO–(40−3 x )SiO 2 – x Si 3 N 4 ( x is the no. of moles of Si 3 N 4 ). The density, glass-transition temperature, hardness, and elastic modulus of each glass were found to increase fairly linearly with nitrogen content. Indentation fracture resistance also increases with nitrogen content according to a power law relationship. These increases are consistent with the incorporation of N into the glass structure in threefold coordination with silicon resulting in extra cross-linking of the glass network. This was confirmed using 29 Si MAS-NMR which showed that an increasing number of Q 2 units and some Q 3 units with extra bridging anions are formed as nitrogen content increases at the expense of Q 1 units. A small proportion of Zn ions are found to be in tetrahedral coordination in the base oxide glass and the proportion of these increases with the presence of nitrogen.

Description: Although it is not possible to predict when an earthquake will occur, many earthquakes have been found to have had some precursor activity. To study precursors of stick-slip behavior, Johnson et al . conducted laboratory experiments on a sheared granular material under normal stress ranging from 2 to 8 megapascals as an analog for a fault under tectonic stress. They found that acoustic emissions and microslips are a precursor to larger movements. Very similar results were obtained in a discrete element simulation of sheared beads. These types of experiments could help scientists better understand when earthquakes are more likely to occur. As shown by a number of researchers, very similar activity preceding faulting can occur in the Earth.

Description: In Arctic seafloor sediments, methane, a potent greenhouse gas, is trapped in chemical structures called hydrates. Methane hydrates form at low-temperature, high-pressure conditions, and methane can be released if the temperature rises. Previous studies have raised concern that global climate change could lead to release of significant amounts of methane from Arctic hydrates.

Description: A 308-year ice core record provides new data on climate variability in coastal West Antarctica and shows that a clear warming trend has occurred in recent decades. To study climate over the past 3 centuries, Thomas et al . analyzed stable isotopes in the ice core, which provide a record of past temperatures. They observed that climate variability in coastal West Antarctica is strongly driven by sea surface temperatures and atmospheric pressure in the tropical Pacific.

Description: When tectonic plates collide, the less buoyant plate will, in some cases, be forced beneath the other. At such subduction zones the sinking tectonic plate, known as a slab, does not follow a simple path from the surface to the deeper mantle. Instead, new research by Fukao and Obayashi suggests that subducting slabs pass through four largely distinct stages as they penetrate toward the core. To systematically catalog the stages of slab subduction, the authors analyzed roughly 10 million observations of the subsurface that were part of a tomographic study that used primary seismic waves to detect the structure of slabs in subduction zones around the Pacific.

Description: It is an honor and privilege to accept the David Perlman Award. Though I have never met Dave, he is a legend, and I can only hope to have a reporting career half as distinguished and a third as long as his own.

Description: It's my pleasure to nominate Paul Voosen, the former science reporter for Greenwire , for the David Perlman award. Last November, as Superstorm Sandy pounded the East Coast of the United States, Paul found himself stranded for several days in Miami, mourning a recently deceased family member.

Description: Some of the most dramatic effects of climate change have been observed in the Earth's polar regions. In Greenland, ice loss from the Greenland ice sheet has accelerated in recent years [ Shepherd et al ., 2012]. Outlet glaciers are changing their behavior rapidly, with many thinning, retreating, and accelerating [ Joughin et al ., 2004]. The loss of ice weighing on the crust and mantle below has allowed both to rebound, resulting in high rock uplift rates [ Bevis et al ., 2012]. Changes in ice cover and meltwater production influence sea level and climate feedbacks; they are expected to contribute to increasing vulnerability to geohazards such as landslides, flooding, and extreme weather.

Description: We review what is presently known about the climate system response to stratospheric ozone depletion and its projected recovery, focusing on the responses of the atmosphere, ocean and cryosphere. Compared to well-mixed greenhouse gases (GHGs), the radiative forcing of climate due to observed stratospheric ozone loss is very small: in spite of this, recent trends in stratospheric ozone have caused profound changes in the Southern Hemisphere (SH) climate system, primarily by altering the tropospheric midlatitude jet, which is commonly described as a change in the Southern Annular Mode. Ozone depletion in the late twentieth century was the primary driver of the observed poleward shift of the jet during summer, which has been linked to changes in tropospheric and surface temperatures, clouds and cloud radiative effects, and precipitation at both middle and low latitudes. It is emphasized, however, that not all aspects of the SH climate response to stratospheric ozone forcing can be understood in terms of changes in the midlatitude jet. The response of the Southern Ocean and sea ice to ozone depletion is currently a matter of debate. For the former, the debate is centered on the role of ocean eddies in possibly opposing wind-driven changes in the mean circulation. For the latter, the issue is reconciling the observed expansion of Antarctic sea ice extent during the satellite era with robust modeling evidence that the ice should melt as a result of stratospheric ozone depletion (and increases in GHGs). Despite lingering uncertainties, it has become clear that ozone depletion has been instrumental in driving SH climate change in recent decades. Similarly, ozone recovery will figure prominently in future climate change, with its impacts expected to largely cancel the impacts of increasing GHGs during the next half-century.

Description: Suzette Kimball, who has served as acting director of the U.S. Geological Survey (USGS) since February 2013, will be nominated to be director of the agency, U.S. president Barack Obama announced on 9 January. If Kimball's nomination is confirmed by the U.S. Senate, she will lead the science agency, which has more than 8000 employees and an annual budget of more than $1.1 billion.

Description: With titles like “Correlates of avian building strikes at a glass façade museum surrounded by avian habitat” and “Electrospray ionization FT-ICR/MS investigation of zinc sulfate clusters,” a series of posters presented at AGU's Fall Meeting on 12 December 2013 might seem like a session covering general contributions from AGU members. However, something was unique about the posters: Most were created and presented by high school students.

Description: This study presents a thermodynamic analysis to predict the type of initial, amorphous oxide overgrowth (i.e., am - Al 2 O 3 or am - SiO 2 ) on bare Al – Si alloy substrates. This analysis have taken into account the energies associated with both its interfaces (interface between the Al – Si alloy substrate and the thin oxide film and interface between the thin oxide film and vacuum) along with the bulk Gibbs free energy of oxide formation. This developed analysis is then applied for various parameters, such as, Si alloying element content at the substrate/oxide interface, the growth temperature, the oxide film thickness (up to 1 nm), and various low-index crystallographic surfaces of the substrate. It is found that am - SiO 2 overgrowth is thermodynamically preferred for a combination of lower oxide film thickness, lower growth temperature, and lower Si alloying content at the alloy/oxide interface. This is because of the overcompensation of the lower energies of both the interfaces over the bulk Gibbs free energy. Furthermore, it is found that for all cases, am - Al 2 O 3 forms a more stable interface with Al – Si alloy than am - SiO 2.

Description: A writer needs two distinct qualities to produce an article like “The Calm Before the Wave,” the piece on tsunamis for which Tim Folger is being honored with the 2013 Walter Sullivan Award. Like any good science writer, he needs the ability to sort through a large mass of scientific information and transform it into a clear, compelling narrative. But he also needs an empathic eye and ear—the ability to feel his way into the lives of people whose stories are utterly different from his own and to see and hear the telling details that will make those people come alive on the page.

Description: The demand for substantial increases in the spatial resolution of global weather- and climate- prediction models makes it necessary to use numerically efficient and highly scalable algorithms to solve the equations of large scale atmospheric fluid dynamics. For stability and efficiency reasons several of the operational forecasting centres, in particular the Met Office and the ECMWF in the UK, use semi-implicit semi-Lagrangian time stepping in the dynamical core of the model. The additional burden with this approach is that a three dimensional elliptic partial differential equation (PDE) for the pressure correction has to be solved at every model time step and this often constitutes a significant proportion of the time spent in the dynamical core. In global models this PDE must be solved in a thin spherical shell. To run within tight operational time scales the solver has to be parallelised and there seems to be a (perceived) misconception that elliptic solvers do not scale to large processor counts and hence implicit time stepping can not be used in very high resolution global models. After reviewing several methods for solving the elliptic PDE for the pressure correction and their application in atmospheric models we demonstrate the performance and very good scalability of Krylov subspace solvers and multigrid algorithms for a representative model equation with more than 10 10 unknowns on 65536 cores on HECToR, the UK’s national supercomputer. For this we tested and optimised solvers from two existing numerical libraries ( DUNE and hypre) and implemented both a Conjugate Gradient solver and a geometric multigrid algorithm based on a tensor-product approach which exploits the strong vertical anisotropy of the discretised equation. We study both weak and strong scalability and compare the absolute solution times for all methods; in contrast to one-level methods the multigrid solver is robust with respect to parameter variations.

Description: This paper is concerned with a dust-raising cold pool over the Sahara desert that occurred on August 3-5, 2006. Both the quantity of the uplifted dust and its spatio-temporal evolution are examined using satellite observations and a numerical simulation. The dust emission during this event was initiated by a mesoscale cold pool emanating from mesoscale convective systems (MCSs) that developed over northern Niger and Mali on August 3. This event is one of several exceptional northward surges of the West African Monsoon (WAM) during the 2006 wet season. We examine the propagation of the cold pool and associated dust lofting using high temporal resolution false-color dust product images from the Meteosat Second Generation Spinning Enhanced Visible and Infrared Imager (MSG-SEVIRI). Observations from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) are used to characterize the vertical structure of the dust cloud as it spreads over the Sahara and across the Atlantic coast. The European Centre for Medium-Range Weather Forecasting African Monsoon Multidisciplinary Analysis (ECMWF-AMMA) special reanalysis was used to describe the synoptic conditions that accompanied this event. Furthermore, a numerical simulation using the mesoscale model MesoNH was performed to estimate the emissions and the westward transport of dust during this event. MODIS AOD satellite imagery has then been used to track the dust plume across the Atlantic Ocean to Barbados, where comparisons are made with the local dust record there. The dusty cold pool covered southern Algeria and a large part of northern Mali and Western Niger attaining a total area close to 2 x 10 6 km 2 . It extended over 2-3 km in altitude and had an aerosol optical depth on the order of 1.5 and an estimated total dust load of about 1.5 Tg on average. Following daytime heating, the dusty cold pool and associated northward surge of moisture favored the development of new convection and additional precipitation over the Sahara. The northward extension of the dusty cold pool was accompanied by a collapse of the Saharan heat low, a characteristic feature of monsoon surges. A model-estimated quantity of 0.4 Tg of the dust produced during this event was subjected to westward transport toward the Atlantic Ocean after being mixed upward in the thickening boundary layer by the daytime heating over the Sahara to altitudes as high as 5-6 km. The arrival of the dust plume in Barbados in the Caribbean Sea 9 days after its departure from the west coast of Africa was characterized by a peak in dust concentration of 48.5 µg. m -3 .

Description: It is customary in atmospheric britishmodelling to approximate the equi-geopotential surfaces of apparent gravity as spheres, and to use spherical polar coordinates to represent the global atmosphere. However Earth's mean surface is more accurately approximated by a spheroid of revolution than by a sphere, and therefore the geopotential surfaces are better represented as spheroidal surfaces than spherical ones. Several authors have considered how to develop a spheroidal coordinate system. The keystone for this is a sufficiently-accurate, yet simple and flexible, mathematical approximation of the geopotential for a spheroidal Earth. Geopotential approximation is a compromise between the extremes of being either too simple, with deficient representation of the essentials of the underlying physics, or too complicated, leading to overly-complicated coordinate systems. A new spheroidal geopotential approximation is proposed herein. It is relatively simple, and analytically tractable, yet properly represents the underlying physics. Using this new approximation, a new, relatively simple, quasi-orthogonal spheroidal coordinate system is developed. It is then straightforward to obtain the customary spherical geopotential approximation, with its associated use of spherical polar coordinates, as an asymptotic limit of this new formulation. This confirms a previous finding, obtained using a different quasi-orthogonal coordinate system. The spheroidal geopotential approximation, and quasi-orthogonal coordinate system, proposed herein are however much simpler, yet no less accurate. They thereby lead to a much simpler, more direct, yet equally rigorous, justification for the spherical geopotential approximation.

Description: We propose a strategy to couple a stochastic lattice-gas model of a cloud system to a rather general class of convective parameterization schemes. As proposed in similar models recently presented in the literature, a cloud system in a grid-box of general circulation model (GCM) is modelled as a sub-grid lattice of N elements which can be in one out of S states, each corresponding to a different convective regime. The time evolution of each element of the lattice is represented as a Markov process characterized by transition rates dependent on large-scale fields and/or local interactions. In order to make applications to GCMs computationally feasible, we propose a reduction method leading to a system of S -1 stochastic differential equations with multiplicative noise. The accuracy of the reduction method is tested in a minimal version of the model. The coupling to a convective scheme is performed in such a way that in the limit of space ant time scale separation the modified stochastic parameterization converges to the original deterministic version of the host scheme. Experiments with a real GCM are then performed coupling the minimal version of the stochastic model to the Betts-Miller scheme in an aqua-planet version of the Planet Simulator. In this configuration the stochastic extension of the parameterization keeps the climatology of its deterministic limit but strongly impacts the statistics of the extremes of daily convective precipitation.

Description: Deformation processes involve systems of tens to hundreds of kilometers moving at highly variable rates. Because direct kinematic observations have proven difficult, geoscientists are sometimes found in the lab creating analogs, or laboratory models of the Earth. The main scope—and a key challenge—of laboratory modeling of Earth systems is to provide a quantitative approach for understanding geological processes. Since the last decade, various image analysis techniques in laboratory modeling have been designed and used to constrain the kinematics of the simulated processes at an unprecedented resolution. These techniques prove to be the key quantification tools in experimental modeling, not only allowing mechanical analysis of the experiments but also producing experimental data sets that are directly comparable to geophysical and geodetic data in nature and numerical models.

Description: Continental scientific drilling is an important tool for exploring natural and anthropogenic processes on Earth. In past decades the results obtained from lake drilling projects contributed significantly to a better understanding of short-term and long-term climate change and natural hazards.

Description: Sintered nanoceramics of Pr -doped lanthanum hafnate, La 2 Hf 2 O 7 : Pr , were prepared by means of a high-pressure sintering technique using nanopowders made by Pechini method. Structure, morphology, and spectroscopic properties of the ceramics compared to the starting powder are presented and discussed. Emission and excitation spectra recorded at room temperature as well as at 7 K using synchrotron radiation are presented together with results of luminescence kinetics measurements. In ceramics, at 7 K, the Pr 3+ luminescence from 3 P 0 (blue-green, green, and red region) and 1 D 2 (red) levels is accompanied by a broad-band emission located in the 380–530 nm range of wavelengths, whereas powders gives only the Pr 3+ -related luminescence. Depending on the excitation wavelength, the broad-band emission maximum moves between 430 and 470 nm indicating superposition of at least two components. In sintered nanoceramics, the lifetimes of Pr 3+ emissions from 3 P 0 and 1 D 2 levels were by 10%–20% shorter compared to the powder. The existence of different luminescence centers was proved by the selective emission decays examination. The fast 5 d → 4 f luminescence of Pr 3+ was not observed from either of the two types of La 2 Hf 2 O 7 :Pr materials.

Description: We, Kevin's friends and colleagues, are pleased to have prepared his nomination package. Across the broad and expansive climate science community, there are very few people who have a history of sustained engagement like Kevin. Whereas many people have worked to convey the importance of climate change, Kevin has tirelessly done so for decades. In addition, the breadth of his activities is astonishing. It includes innumerable interviews on radio, on television, and in printed media over the past 30 years. He has also taken on many leadership communication roles within the scientific community, including the Intergovernmental Panel on Climate Change to name just one.

Description: Ted Flinn and John LaBrecque followed remarkably, perhaps eerily, similar career paths. Ted started as a seismologist, John as a tectonician and sea-going geophysicist. Both decided to rededicate their efforts toward supporting the geophysical community, recognizing that it depends ever more critically on global, space-based measurements and observations. Ted did that a decade after the 1968 Williamstown conference, and John did it a decade after the 1988 Coolfont conference. Both of these history-making conferences focused on the geophysical uses of space assets to study the planet.

Description: Chapman conferences are intended for deeper discussions of specific topical areas of scientific interest. This Chapman conference was organized to review and discuss new strategies to observe and understand processes and drivers in the biogeosphere, particularly those related to coupled biogeochemical and hydrological processes in terrestrial systems. The topics presented at the meeting included transport and exchange processes of organic and gaseous compounds across the soil-water and soil-plant interfaces, monitoring strategies of soil-mediated processes and drivers from the local to the catchment scale, and the impact of soil formation and functions on ecosystem services. These topics were addressed and intensively discussed by participants covering the fields of soil systems sciences, hydrology, and biogeosciences.

Description: It is a great pleasure and an honor to give the citation for the 2013 Athelstan Spilhaus awardee, Iain Stewart, professor of geoscience communication at the University of Plymouth, recognizing his truly exceptional work over the last decade in communicating geoscience to the general public. Iain has been making documentaries for the BBC, National Geographic, and Discovery for nearly a decade. These programs have huge international audiences and wide-reaching impact.

Description: I am delighted to be recognized with this prize. I want to first thank AGU and the prize committee and, especially, Nature's Own for establishing this prize in a field that has become contentious and highly political. It did not used to be this way. Following the media frenzy with the 2007 Intergovernmental Panel on Climate Change (IPCC) report, there was hope at the 2009 Conference of Parties meeting in Copenhagen that an international framework agreement on climate change might be achieved. It was not to be. Planned actions to address issues of climate change were undermined by huge funding of misinformation by vested interests. It was not helped by so-called “climategate” in which many emails illegally hacked from a computer server at the University of East Anglia in the United Kingdom were released, cherry picked, distorted, and misused by climate change deniers. Minor errors in the IPCC report were blown out of all proportion and ineffectively addressed. I was caught up in all this, and one of my many emails went viral: the “travesty” quote in which I bemoaned the inability to close the global energy balance associated with short-term climate variability but which was misinterpreted as saying there was no global warming. These examples highlight failures of communication.

Description: Solomon Hsiang is representative of a new generation in the geosciences community, whose work spans several disciplines, drawing on methods and concepts from far outside the traditional physical science domain in order to make progress on difficult questions at the intersection of natural science, social science, and public policy. Broadly speaking, by examining how humanity has responded to climate variability and change in the distant and recent past, Sol's research elucidates the question of how humanity may respond to a changing climate in the future. Combining large, independent sets of social science, meteorological, and climatological data and analyzing them with tools more common in microeconomics than natural science, Sol, still at an early stage of his career, has made critical contributions to an incipient revolution in our understanding of the sensitivity and adaptability of humans and their social arrangements to climate variability and change. Such insights will greatly improve the information base from which effective public policy is developed.

Description: Thanks to AGU and our citationist, Richard Alley, for this joint award to Erna and myself. While it is, of course, personally gratifying, we also consider it an acknowledgement that “science journalism” has broadened out from print to include video in all forms—from PBS primetime to YouTube anytime—and also social media and spoken-word presentations. We're pleased that this is one more way in which AGU is validating the participation of its members in all forms of public outreach. We're gratified that our efforts in this regard have been supported by NSF, NASA, and NOAA, among other government agencies, and are happy to acknowledge their “priceless” role as funders. As one of our current collaborators, former NASA chief scientist Waleed Abdalati, likes to say, “The science isn't done until it's shared”…and there are more and more ways in which that sharing can be done.

Description: On 24 August 2013 a sudden burst of gas erupted from the ground near Rome's airport, about 15 kilometers southwest of the city. The eruption produced a crater that was initially about half a meter wide but that gradually increased in size and eventually reached a diameter of about 3 meters.

Description: Dr. Chelle Gentemann is a worthy recipient of the Charles S. Falkenberg Award. Through her leadership at both national and international levels, Chelle has contributed significantly to improving the accuracy, accessibility, and utility of satellite-derived fields of sea surface temperature (SST) for a wide range of applications, including numerical weather forecasting, operational oceanography, and climate research.

Description: Thank you, Cinna, for your kind and generous citation and for your friendship. It is a great recognition having been selected for the 2013 International Award. I feel honored, especially considering the international breadth of AGU, fostering scientific excellence and promoting research in Earth and space sciences worldwide. AGU has evolved over the years, becoming increasingly international and multidisciplinary, providing the intellectual framework and networking for research collaboration. I have been privileged to serve as International Secretary of the Union, which together with work in the committees permitted me to better appreciate the range of activities and the programs AGU does to serve its membership and the geophysics community.

Description: The meaning of “interdisciplinary” has evolved over my career. When I started my science research career, it meant bridging atmospheric and ocean science and embracing the science of the Earth system and its interacting components. Thus, I found a home at AGU submitting science abstracts to atmospheric science, oceanography, or hydrology sessions. In fact, my first research paper appeared in Journal of Geophysical Research (JGR)-Atmospheres , and a letter to the editor and response appeared in JGR-Oceans . It also meant getting scientists in these disciplines talking to each other. I organized a seminar series at Rice University under the umbrella of an Earth Systems Institute that included the Departments of Space Physics and Astronomy, Geology and Geophysics, Biology, and Hydrology. I also began working with Dr. Patricia Reiff, a space physicist with a passion for science education.

Description: It is really wonderful to receive this award and the recognition of AGU for my work. I've been a member of the Union since my Ph.D. days, 25 years or so ago, when I was working on earthquake faulting in Greece and Turkey. Its meetings were always the place that showcased geoscience at its most novel and exciting. It was the breadth of what was on offer that was so exhilarating. My doctoral studies had already opened up fairly wide vistas for me since my interest in Holocene earthquake activity also required an understanding of the Mediterranean's rich cultural history and the vagaries of millennial-scale climate fluctuations. Later, my research would distract me into farther-flung realms, such as volcanic faulting on Mount Etna, paleotsunamis along Aegean shores, even postglacial earthquakes in northern Scotland! Kindly colleagues would occasionally advise me to focus my efforts on a single substantive area of research, cautioning that my flighty research forays weren't conducive to climbing the academic ladder. I'm sure they were correct. Or would have been proved so if I hadn't been rescued by television.

Description: I am honored to receive this award, created by Peter Schlosser, nominated by my postdoc advisor Michael Oppenheimer, and alongside my thesis advisor Mark Cane, recipient of this year's Maurice Ewing Medal—all role models and original pioneers in “the application and use of Earth and space sciences to solve societal problems.”

Description: A question about how to predict the runoff from a basin where there is no history of flow measurements is probably featured in almost every hydrology graduate student's oral examinations. It has certainly been one of the longest-standing problems for the profession. The International Association of Hydrological Sciences Prediction in Ungauged Basins initiative [ Wagener et al ., 2004] has focused researchers and meetings on the topic, culminating in this book, which assembles the thoughts gathered over the last decade.

Description: From Cosmos to Mars and Pluto and back home, Geoffrey Haines-Stiles and Erna Akuginow have invested their careers reporting the best modern science in novel, compelling, and accessible ways through documentaries, live events, print, and new media. They are outstanding recipients of the AGU Robert C. Cowen Award for Sustained Achievement in Science Journalism.

Description: Clouds' effects on climate are significant and complex. Many cloud processes occur at small scales and are difficult to calculate in large-scale models, so general circulation models typically use parameterizations to represent a range of cloud properties.

Description: We examine the physical constraints that must be satisfied to allow for a steady-state tropical cyclone in an isolated environment, paying particular attention to the need to replenish absolute angular momentum exactly at the rate that it is consumed and to the vanishing of the spin-up function above the frictional boundary layer. We conclude that it is unlikely that these conditions will be met simultaneously and question whether globally steady-state tropical cyclone solutions have merit. The implications for previous studies are discussed.

Description: Nine AGU members are among the 102 researchers that U.S. president Barack Obama announced on 23 December as recipients of the Presidential Early Career Awards for Scientists and Engineers, the highest honor bestowed by the U.S. government on science and engineering professionals in the early stages of their independent research careers.

Description: An 8 January decision by the White House to propose an extension of the International Space Station's (ISS) operation until at least 2024 would allow for increased research on board the floating laboratory, a longer planning horizon for commercial activities, and a continuation of international cooperation in space, administration officials said. The proposal, which has received initial support from some key members of Congress, would be the second extension for ISS under the Obama administration and would accommodate increased research related to long-duration human space flight, Earth science, and other areas. ISS, which in the United States is authorized under the NASA Authorization Act of 2010, was last extended in 2010 and costs about $3 billion annually to operate.

Description: Since 2011, the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) and three major river forecasting centers of the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) have discontinued a long-standing practice of publishing consensus water supply forecasts in western U.S. river basins.

Description: Atmospheric and Space Electricity (ASE)

Description: Hawaii's Kīlauea volcano has been erupting since 1983. Starting in 2003, researchers noticed an inflation of the magma chamber beneath the volcano; this inflation accelerated in 2006. In June 2007, the volcano's eruption peaked with a burst of activity known as the Father's Day event. In the buildup to those eruptions, according to new research by Wauthier et al ., a pair of large-magnitude earthquakes hit, with an epicenter beneath the volcano. Earthquakes are common around the volcano, which sits on Hawaii's Big Island, but with magnitudes of 4.7 and 4.1, the two 2007 earthquakes were among the most powerful recorded in the region since records began in 1959.

Description: When the temperature rises on Baffin Island, in the Canadian high Arctic, ancient Polytrichum mosses are exposed from beneath melting glacier ice. Within a few years of exposure the mosses are quickly eroded away by snow and wind, but trapped beneath the ice, they can remain, frozen, for thousands of years.

Description: Since the first up-close observations of Saturn, made by the Pioneer 11 probe in 1979, a great deal has been learned about the dynamics of the gas giant's magnetosphere. In-depth observations made by the Cassini orbiter, which has been circling Saturn since 2004, have revealed fundamental differences between the behavior of Saturn's magnetosphere and that of the Earth's magnetosphere. Earth's magnetospheric plasma is largely populated by ions captured from the solar wind, whereas Saturn's plasma comes predominantly from water vapor that spews from massive geysers on the southern end of its icy moon Enceladus. Ionized water vapor from Enceladus streams out at 12 to 250 kilograms per second, yet observations show that the concentration of plasma in Saturn's magnetosphere is at a relatively steady level. This discrepancy has left researchers searching for potential plasma loss mechanisms. In a review, Thomsen highlights the progress made in recent years in understanding this question.

Description: We have investigated the electromechanical response of potassium sodium niobate ( K 0.5 Na 0.5 NbO 3 or KNN) thick films. The high-field strain hysteresis loops and weak-field converse piezoelectric d 33 coefficient of the films were measured and compared with those of KNN bulk ceramics under the same electric field conditions. The converse d 33 values of the thick films and bulk ceramics were equal to 82.5 and 138 pm/V, respectively, at 0.4 kV/mm. The fundamental difference between the piezoelectric response of the KNN films and the ceramics was studied in terms of the effective (“clamped”) piezoelectric d 33 coefficient. The reduction in the piezoelectric d 33 coefficient of the KNN films, resulting from the clamping by the substrate, was compared to lead-based ferroelectric thick films, including Pb ( Zr , Ti ) O 3 (PZT) and (1 −  x ) Pb ( Mg 1/3 Nb 2/3 ) O 3 − x PbTiO 3 (PMN-PT). We propose a possible explanation, based on the particular elastic properties of KNN, for the small relative difference observed between the “clamped” and “unclamped” (“bulk”) d 33 of KNN, in comparison with lead-based systems.

Description: Lead zirconate titanate (PbZr 1 −  x Ti x O 3 , PZT)/epoxy composites with one- dimensional epoxy in PZT matrix (called 3-1 type piezocomposites) have been fabricated by tert-butyl alcohol (TBA)-based directional freeze casting of PZT matrix and afterward infiltration of epoxy. The composites with PZT volume fraction ranging from 0.36 to 0.69 were obtained by adjusting initial solid loading in freeze-casting slurry. The effect of poling voltage on piezoelectric properties of the composites was studied for various volume fraction of PZT phase. With the increasing of PZT volume fraction, relative permittivity (ε r ) increased linearly and piezoelectric coefficient ( d 33 and d 31 ) increased step by step. The resultant composites with 0.57 PZT volume fraction possessed the highest hydrostatic piezoelectric strain coefficient ( d h ) value (184 pC/N), voltage coefficient ( g h ) value (13.6 × 10 −3  V/m Pa), and hydrostatic figure of merit (HFOM) value (2168 × 10 −15  Pa −1 ).

Description: Multiphase borosilicate glass-ceramics represent one candidate to contain radioactive nuclear waste separated from used nuclear fuel. In this work, the thermophysical properties from room temperature to 1273 K were investigated for four different borosilicate glass-ceramic compositions containing waste loadings from 42 to 60 wt% to determine the sensitivity of these properties to waste loading, as-fabricated microstructure, and potential evolutions in microstructure brought about by temperature transients. The thermal expansion, specific heat capacity, thermal diffusivity, and thermal conductivity are presented. The impact of increasing waste loading is shown to have a small but measurable effect on the thermophysical properties between the four compositions, contrasted to a much greater impact observed when transitioning from predominantly crystalline to amorphous systems. Thermal cycling below 1273 K was not found to measurably impact the thermophysical properties of the compositions investigated here.

Description: The 27 February release of an environmental review of geological and geophysical (G&G) survey activities off the mid- and South Atlantic outer continental shelf is a key step toward potentially opening the area to oil and gas exploration, according to industry and environmental groups. That is a prospect industry groups favor and environmental groups say will harm marine life.

Description: Scientific discovery, technological revolutions, and complex global challenges are commonplace in the modern era. People are bombarded with news about climate change, pandemics, and genetically modified organisms, and scientific literacy has never been more important than in the present day. Yet only 29% of American adults have sufficient understanding to be able to read science stories reported in the popular press [ Miller, 2010], and American students consistently rank below other nations in math and science [ National Center for Education Statistics, 2012].

Description: In the shadow of the Matterhorn, the broad form of the Matter Valley—like so many throughout the Alps—is interrupted by a deep U-shaped glacial trough. Carved into a landscape reflecting millennia of tectonic uplift and river erosion, growing evidence suggests the 100-meter-deep U-shaped groove was produced shortly after a shift toward major cycles of Alpine glaciation almost a million years ago. Subsequent glaciations may have therefore had little effect on the landscape.

Description: The U.S. Senate confirmed Kathryn Sullivan as under secretary of commerce for oceans and atmosphere on 6 March. She also becomes administrator of the National Oceanic and Atmospheric Administration (NOAA).

Description: The proposed federal budget for fiscal year (FY) 2015, released by the White House on 4 March, would provide small increases for a number of science agencies, although some, including NASA, would see a dip in funding. Overall, the budget proposes $135.4 billion for federal research and development (R&D) activities, an increase of $1.7 billion (1.2%) over the FY 2014 enacted levels.

Description: This review assesses storm studies over the North Atlantic and Northwestern Europe regarding the occurrence of potential long-term trends. Based on a systematic review of available articles, trends are classified according to different geographical regions, data sets, and time periods. Articles that used measurement and proxy data, reanalyses, regional and global climate model data on past and future trends are evaluated for changes in storm climate. The most important result is that trends in storm activity depend critically on the time period analysed. An increase in storm numbers is evident for the reanalyses period for the most recent decades, whereas most long-term studies show merely decadal variability for the last 100-150 years. Storm trends derived from reanalyses data and climate model data for the past are mostly limited to the last four to six decades. The majority of these studies find increasing storm activity north of about 55-60 ° N over the North Atlantic with a negative tendency southward. This increase from about the 1970s until the mid-1990s is also mirrored by long-term proxies and the North Atlantic Oscillation and constitutes a part of their decadal variability. Studies based on proxy and measurement data or model studies over the North Atlantic for the past which cover more than 100 years show large decadal variations and either no trend or a decrease in storm numbers. Future scenarios until about the year 2100 indicate mostly an increase in winter storm intensity over the North Atlantic and Western Europe. However, future trends in total storm numbers are quite heterogeneous and depend on the model generation used.

Description: We report a novel oscillatory pressure-assisted hot-pressing process for preparing high-quality ceramics. Compared with the samples prepared by conventional pressureless sintering (PS) and hot-pressing (HP), the zirconia ceramic prepared by oscillatory pressure-assisted hot-pressing (OPAHP) exhibited a higher density, smaller grain size, and more homogeneous structure. More remarkably, the strength of the OPAHP sample reached 1556 MPa, which is much higher than the samples prepared by other two techniques. The results suggest that OPAHP is a more effective technique for preparing high-quality zirconia, which is likely applicable to other material systems.

Description: The formation of a homogeneous Bi 8 TiO 14 phase was successfully achieved in a specimen calcined at 600°C. However, a Bi 4 Ti 3 O 12 secondary phase also developed in specimens calcined at temperatures higher than 600°C, probably because of Bi 2 O 3 evaporation. For specimens sintered above 800°C, a small amount of the Bi 8 TiO 14 phase melted during sintering, with the liquid phase contributing to the densification of the specimens; however, Bi 4 Ti 3 O 12 and Bi 12 TiO 20 secondary phases were still formed in these specimens. The microwave dielectric properties of the Bi 8 TiO 14 phase were considerably affected by variations in the microstructure of the specimens. When the sintering temperature exceeded 825°C, the amount of secondary phases increased, and this decreased the density and Q×f values of the specimens. Bi 8 TiO 14 ceramics sintered at 825°C exhibited promising microwave dielectric properties, with ε r = 47.4, Q×f  =   5370 GHz, and τ f = −16.01 ppm/°C.

Description: In the weak-wind nocturnal boundary layer, the wind direction near the surface may vary substantially with height. The directional shear is caused by transient modes and shallow, terrain-induced motions. This study examines the large directional shear for nocturnal data collected in the lowest 10 m from three field programs. The directional shear in two broad valleys with high sidewalls is dominated by transient motions within the valley cold pool. In contrast, the directional shear within a shallow narrow valley is dominated by terrain-induced downvalley drainage flows, in spite of the fact that magnitude and the height of the valley sidewalls are much smaller compared to the other two valleys. The relative contribution of the directional shear to the total vector shear is examined as a function of wind speed and stability.

Description: We demonstrate that summer precipitation biases in the South Asian monsoon domain are sensitive to increasing the convective parametrisation's entrainment and detrainment rates in the Met Office Unified Model. We explore this sensitivity to improve our understanding of the biases and inform efforts to improve convective parametrisation. We perform novel targeted experiments in which we increase the entrainment and detrainment rates in regions of especially large precipitation bias. We use these experiments to determine whether the sensitivity at a given location is a consequence of the local change to convection or is a remote response to the change elsewhere. We find that a local change leads to different mean-state responses in comparable regions. When the entrainment and detrainment rates are increased globally, feedbacks between regions usually strengthen the local responses. We choose two regions of tropical ascent that show different mean-state responses, the western equatorial Indian Ocean and western north Pacific, and analyse them as case studies to determine the mechanisms leading to the different responses. Our results indicate that several aspects of a region's mean-state, including moisture content, sea surface temperature and circulation, play a role in local feedbacks that determine the response to increased entrainment and detrainment.

Description: In general particle filters need large numbers of model runs in order to avoid filter degeneracy in high-dimensional systems. The recently proposed, fully nonlinear equivalent-weights particle filter overcomes this requirement by replacing the standard model transition density with two different proposal transition densities. The first proposal density is used to relax all particles towards the high-probability regions of state space as defined by the observations. The crucial second proposal density is then used to ensure that the majority of particles have equivalent weights at observation time. Here the performance of the scheme in a high, 65,500 dimensional, simplified ocean model is explored. The success of the equivalent-weights particle filter in matching the true model state is shown using the mean of just 32 particles in twin experiments. It is of particular significance that this remains true even as the number and spatial variability of the observations are changed. The results from rank histograms are less easy to interpret and can be considerably influenced by the parameter values used. This article also explores the sensitivity of the performance of the scheme to the chosen parameter values and the effect of using different model error parameters in the truth compared to the ensemble model runs.

Description: A new solid solution of (1− x ) Pb ( Mg 1/2 W 1/2 ) O 3 – x Pb ( Zn 1/2 W 1/2 )O 3 has been prepared in the form of ceramics by solid-state reaction with composition x up to 30%. It is found that with the substitution of Zn 2+ for Mg 2+ on the B site of the of complex perovskite structure the antiferroelectric (AFE) Curie temperature T C of PMW increases from 40°C ( x  = 0) to 67°C ( x  = 30%), indicating an enhancement of antiferroelectric order, whereas, at the same time, the phase transition becomes more diffuse due to a higher degree of chemical inhomogeneity. X-ray diffraction analysis indicates that the crystal structure adopts an orthorhombic space group ( Pmcn ) with a decrease in lattice parameter a, but an increase in b and c as the Zn 2+ concentration increases. The low dielectric constant (~ 10 2 ), low dielectric loss (tanδ ≈ 10 −3 ), linear-field-induced polarization, and significantly high breakdown field (~ 125 kV/cm) at room temperature make this family of dielectric materials a promising candidate for ceramic insulators.

Description: Secretary of the Interior Sally Jewell released a new strategy on 10 April 2014 to advance landscape-scale, science-based management of America's public lands and wildlife. The strategy will implement mitigation policies and practices at the Department of the Interior that can encourage infrastructure development while protecting natural and cultural resources.

Description: The U.S. Geological Survey (USGS) has released the latest edition of its National Land Cover Database (NLCD 2011), the nation's most comprehensive look at land surface conditions. The database divides the lower 48 states into 9 billion geographic cells, providing consistent information about land conditions on regional and nationwide scales.

Description: Energetic protons emitted in bursts from the Sun pose a potential hazard for spacecraft, satellites, humans in space, and aircraft at high latitudes. Researchers have now verified that a set of sensors used to measure solar proton events are correctly intercalibrated to provide early warning of the events.

Description: A little more than 50 years ago, on 27 March 1964, the Great Alaska earthquake and tsunami struck. At moment magnitude 9.2, this earthquake is notable as the largest in U.S. written history and as the second-largest ever recorded by instruments worldwide. But what resonates today are its impacts on the understanding of plate tectonics, tsunami generation, and earthquake history as well as on the development of national programs to reduce risk from earthquakes and tsunamis.