bluuebunny/crossref_metadata_2025 huggingface dataset:
Durchbewegt sulphides, piercement structures, and gabbro dyke displacement in the vent complex of the Sullivan Pb-Zn deposit, British Columbia
Authors: Paakki J J , Lydon J W , Del Bel Belluz N
Published: April 2013

Offsets of gabbro dykes indicate that relative movement between hanging wall and footwall of the Sullivan deposit was multi-directional and resulted in net movement of less than 150 m. These movements produced semi-concordant zones of high strain within the vent
complex sulphides, which are marked by durchbewegung structure near the base of the sulphide body and by zones of foliated galena-rich sulphide within the interior of the deposit. Footwall cusps formed during compressional reactivation of north-trending fault structures that mark the margins of a
pre-ore graben structure. Hanging wall piercement cusps and associated discordant durchbewegt sulphide are confined to the eastern margin of this structure. Faults of this graben structure focussed hydrothermal flow during the main ore-forming event. At the peripheries of the deposit, sulphides have
been mechanically remobilized beyond their original extent.
A note on U-Pb dating of Middle Jurassic plutonic suites: Cumshewa Head pluton, southeastern Moresby Island, Queen Charlotte Islands, British Columbia
Authors: Anderson R G , McNicoll V J
Published: April 2013

A new U-Pb date of 167 ± 2 Ma for the Cumshewa Head pluton corroborates the pluton's previous correlation with the Middle Jurassic (168 to 158 Ma) Burnaby Island plutonic suite based on plutonic style.
Stratigraphy and structure of the Driftpile stratiform Ba-Zn-Pb deposit, Gataga area, northeastern British Columbia
Authors: Paradis S , Nelson J L , Farmer R
Published: April 2013

The Driftpile deposit is hosted by fine-grained carbonaceous black siliciclastic rocks of the Middle to Late Devonian Lower Earn Group, in a series of imbricate northeastward-verging thrust panels. Mineral assemblages consist of two distinct facies occupying two
different stratigraphic positions - a localized, lower sulphide-carbonate facies and a laterally extensive upper barite (±sulphides) facies. The footwall is massive mudstone or siliceous to cherty carbonaceous argillite interbedded with radiolarian-rich chert and locally with cryptic pyrite
laminated mudstone. Hanging wall rocks are turbidite lithofacies overlain by concretionary shale and nodular mudstone. This stratigraphic sequence with two cycles of mineralization, each preceded by a period of anoxic, starved sedimentation and succeeded by an influx of turbidites, represents an
interplay of mineralizing and tectonic events, with discrete episodes of faulting triggered the release of metalliferous basinal brines into anoxic bottom waters and then the sudden and rapid influx of turbidites.
Quaternary geology and terrain inventory, eastern Cordillera NATMAP Project. Report 1: regional landslide characterization
Authors: Jackson L E
Published: April 2013

The Foothills area in southwestern Alberta can be subdivided into four provinces, each with distinctive types or suites of landslides. The Porcupine Hills/Interior Plains are characterized by slumps and earthflows on slopes steepened by fluvial activity. The
Foothills have a low frequency of landsliding since slope angles are generally smaller than bedding plane dips. Glaciolacustrine valley fills form the floors of Foothills valleys and fail as rotational slumps and flows. Rockslides cluster along major thrust faults in the Rocky Mountains where
Mesozoic clastics have been sheared. Rock avalanches are largely confined to Paleozoic units. Slope instability apparently does not decrease with time in the Rocky Mountains. Ongoing mass wasting processes appear to be steepening slopes below massive, mountain-forming Paleozoic carbonates and
quartzites.
Groundwater in the Palliser Triangle: an overview of its vulnerability and potential to archive climate information
Authors: Remenda V H , Birks S J
Published: April 2013

Groundwater is an important but poorly delineated resource in the drought-sensitive Palliser Triangle. Much of the rural population of the region relies on groundwater as a water supply. Groundwater discharge provides base flow to many surface-water bodies,
including shallow lakes. Both bedrock and glacial deposits form important aquifers, although their water quality and sensitivity to climate fluctuations, over exploitation, and contamination vary. Ironically, it is the most vulnerable aquifers that contain the highest quality water. Groundwater is a
potential archive of past climate fluctuations, both directly in the form of stable isotope concentrations, and indirectly in the depths to which water tables declined in response to Holocene climate change. To date, no observations of such changes have been made at temporal scales useful for
drought management. The spatial and temporal scales of groundwater systems discharging to lakes, the hydrochemistry, and the volume and source of water all have the potential to damp the connection between proxy indicators of lake level and precipitation.
Mineralogy, lithostratigraphy, and inferred geochemical history of North Ingebrigt lake, Saskatchewan
Authors: Shang Y , Last W M
Published: April 2013

North Ingebrigt lake, a small, hypersaline playa basin in the Great Sand Hills of southwestern Saskatchewan, contains one of Canada's thickest Holocene terrestrial salt sequences. The 10 000-year long lacustrine sequence from the basin consists of well indurated
salt, with only minor mud and organic debris. Cores lack obvious bedding, colour variation, or other visible sedimentary structures. The mineral suite consists mainly of hydrated Na-, Mg-, Ca-, and (Na+Mg)-sulphates, -carbonates, and -chlorides. This long and apparently uninterrupted sequence of
soluble salts implies that the lake was characterized by high salinity throughout its Holocene history. Preliminary chronostratigraphy indicates that accumulation rates have varied greatly in the past. Similarly, variations in salt mineralogy suggest that the basin experienced significant changes in
brine composition. These evaporites permit reconstruction of specific ion activities and ratios in the brine through time, providing the first detailed evidence of the complexity of brine evolution in a closed-basin lacustrine environment in western Canada
Late Holocene paleolimnology of Killarney Lake, Manitoba
Authors: Richmond K -A , Goldsborough L G
Published: April 2013

Analyses of organic matter, total phosphorus, pigments (chlorophylls, total carotenoids, myxoxanthophyll, oscillaxanthin), and diatoms were used to infer late Holocene trends in primary production for Killarney Lake, southwestern Manitoba. At 4700 BP the lake was
relatively shallow and unproductive. Water levels and production then rose, likely due to a cooler and wetter climate. A deep, unproductive lake existed by about 2100 BP. Water levels decreased and production increased about 1200 BP. Water levels increased again about 500 BP but did not reach the
level of the previous deep-water stand. Production has increased during the last 100 years, possibly due to anthropogenic influences in the watershed. Collectively, these analyses indicate that Killarney Lake has been mesotrophic to eutrophic for at least the last five millennia. The similarity of
its developmental sequence to those of other prairie lakes, especially in eastern Saskatchewan, indicates a close linkage between lake-water level, production, and regional climate.
Using optical dating to determine when a sediment was last exposed to sunlight
Authors: Huntley D J , Lian O B
Published: April 2013

Optical dating has now been established as a method that can be used to determine when quartz or feldspar grains in sediment were last exposed to sunlight. In this review, we outline the processes that occur in these minerals while in the environment, and the
laboratory techniques used to obtain an age estimate. The questions "Are optical ages correct?" and "What can go wrong?" are addressed. Examples are provided of cases where optical ages are in agreement with ages obtained using other methods. Examples are also given for instances where unexpected
ages were obtained, and possible resolutions are discussed. Emphasis is placed on the necessity of sufficient sunlight exposure prior to burial, and the degree to which this depends on the environmental circumstances. The examples chosen are primarily from our work in western Canada and they are
intended to show what a geoscientist can and cannot expect of optical dating.
Activity cycle of parabolic dunes based on morphology and chronology from Seward sand hills, Saskatchewan
Authors: David P P , Wolfe S A , Huntley D
J , Lemmen D S
Published: April 2013

Morphological and chronological data are used to develop a conceptual model of parabolic sand-dune reactivation and stabilization in response to changing climate, referred to as an activity cycle. The duration of an activity cycle is controlled by moisture
availability. Optical ages from the back ridges and dune-track ridges of adjacent dunes in Seward sand hills demonstrate that the last cycle occurred during the nineteenth century. Ages of ridges behind the smaller of two dunes appear congruous, becoming older with depth and younger downwind,
whereas those from the larger dune record depositional events subsequent to the formation of major morphological features. Initial rates of dune advance were rapid in response to climatic stress accumulated in the dunes. Water table fluctuations interrupted dune migration at least four times,
producing dune-track ridges. Rates of advance following formation of the first dune-track ridge averaged about 2.2 m·a-1, similar to those of presently active dunes in the region.
Geomorphic surfaces and postglacial landscape evolution of the Maple Creek basin, Saskatchewan
Authors: Vreeken W J
Published: April 2013

Maple Creek basin, a 75 km long closed drainage in southwestern Saskatchewan, contains well differentiated, postglacial, fluvial and lacustrine geomorphic surfaces in addition to relict preglacial, glacial, and glaciolacustrine surfaces. Deglaciation (ca. 18
000-13 000 BP) produced vast tracts of internally drained hummocky moraine and cross-valley glaciogenic barriers that gave rise to through-flowing postglacial lakes. Postglacial Junction and Hanson lakes regulated flow to the terminus and functioned as sediment traps and temporary base levels for
stream erosion upvalley, until their demises at about 6000 and 1500 BP, respectively. The major geomorphic events controlling the postglacial evolution of the basin were not climatically controlled. Rather, they reflect the delayed (up to 11 000 years) geomorphic response to deglacial landscape
instability. Direct response to Holocene climatic change is largely restricted to fluvial-runoff processes, such as alluvial-fan formation and hillslope erosion, that can remain unaffected by base-level changes. Both show intervals of accelerated activity that correlate with the warm and dry
Hypsithermal climate interval (ca. 9000-4600 BP).
Recognizing Scientific Artifacts in Biomedical Literature
Authors: Groza Tudor , Hassanzadeh Hamed , Hunter Jane
Published: April 2013

Today's search engines and digital libraries offer little or no support for discovering those scientific artifacts (hypotheses, supporting/contradicting statements, or findings) that form the core of scientific written communication. Consequently, we currently have no means of identifying central themes within a domain or to detect gaps between accepted knowledge and newly emerging knowledge as a means for tracking the evolution of hypotheses from incipient phases to maturity or decline. We present a hybrid Machine Learning approach using an ensemble of four classifiers, for recognizing scientific artifacts (ie, hypotheses, background, motivation, objectives, and findings) within biomedical research publications, as a precursory step to the general goal of automatically creating argumentative discourse networks that span across multiple publications. The performance achieved by the classifiers ranges from 15.30% to 78.39%, subject to the target class. The set of features used for classification has led to promising results. Furthermore, their use strictly in a local, publication scope, ie, without aggregating corpus-wide statistics, increases the versatility of the ensemble of classifiers and enables its direct applicability without the necessity of re-training.
Interpolation of Morrey Spaces on Metric Measure Spaces
Authors: Lu Yufeng , Yang Dachun , Yuan Wen
Published: April 2013

In this article, via the classical complex interpolation method and some interpolation methods traced to Gagliardo, the authors obtain an interpolation theorem for Morrey spaces on quasimetric measure spaces, which generalizes some known results on ℝn.
Calidad de vida en el paciente pediátrico con Enfermedad Renal Crónica
Authors: López Soto Pablo Jesús
Published: April 2013

Objetivos: Conocer la producción científica en los últimos seis años sobre la calidad de vida de los pacientes pediátricos con enfermedad renal crónica.
Métodos: Las bases de datos consultadas fueron PubMed, Scopus, Science Direct, ProQuest, Web of Knowledge y SciVerse. Sólo se incluyeron los artículos científicos escritos en inglés o español y que tuvieran un diseño de corte transversal. Las principales variables que afectan a la calidad de vida eran analizadas, entre las que destacaba la modalidad terapéutica. Además, se estudió los distintos cuestionarios de medición de la calidad de vida, así como las diferencias en la percepción entre los pacientes y sus familias.
Resultados: Trece documentos fueron encontrados: sólo uno de ellos empleó un cuestionario específico para este tipo de pacientes, diez cuestionarios generales y los dos documentos que empleaban los dos tipos. Los cuestionarios generales estudiaban la variable de "modalidad terapéutica" que se emplea, así como otros factores que afectan a la calidad de vida tales como trastornos del sueño y mentales; por otro lado, el cuestionario específico sólo estudió la variable "modalidad terapéutica". En los dos estudios que emplean ambos tipos de cuestionarios la principal variable de estudio es la "modalidad terapéutica" y se permite una comparación entre los dos tipos de cuestionarios.
La mayor parte de los estudios emplean un informe parental para determinar la calidad de vida del paciente pediátrico con enfermedad renal crónica.
Conclusiones: Los pacientes pediátricos con enfermedad renal crónica tienen una peor calidad de vida que los pacientes pediátricos con otras enfermedades crónicas tales como diabetes. Los niños trasplantados o en tratamiento conservador poseen una mejor calidad de vida que los sometidos a tratamiento sustitutivo.
La diferencia entre tiempo programado y efectivo en hemodiafiltración en línea: ¿Cada minuto cuenta en la eficacia dialítica?
Authors: Fernández Martínez Ana Vanessa , Pérez Díaz Rocío , Pérez Valencia Laura , Caparros Ríos Virginia , Espinosa Sáez Mª José , Romero Willhoft Verena , Pereira Martínez Mª Soledad
Published: April 2013

Introducción: El factor tiempo es determinante en la eficacia de la diálisis, recomendando las European Best Practices Guides of Dialysys Adequaccy una duración semanal no inferior a 720 minutos.
Los modernos monitores de diálisis interrumpen el procedimiento por auto chequeos que incrementan la seguridad. Esos minutos de diferencia no han sido tenidos en cuenta en otros resultados obtenidos, algún autor ya hace referencia a la necesidad de contemplarlos.
Los objetivos del presente estudio fueron determinar la diferencia real entre el tiempo programado y el tiempo efectivo de diálisis, y una vez comprobado incrementar la duración de la sesión para hacer que el tiempo efectivo sea realmente el deseado en cada paciente, y nunca inferior a 240 minutos por sesión. Finalmente comprobamos si existen diferencias en la eficacia dialítica, midiendo el Kt y el volumen total de reinfusión.
Pacientes y métodos: Diseñamos un estudio prospectivo sobre población prevalente en hemodiafiltración on-line. Reclutamos 152 pacientes en hemodiafiltración on-line. Durante 6 sesiones consecutivas (912 sesiones) la diálisis se efectuó con un tiempo programado = 240 minutos. En un segundo periodo 6 sesiones consecutivas (912 sesiones), la sesión de diálisis se alargó hasta un tiempo efectivo igual al previo programado.
La variable principal en estudio fue el tiempo, siendo variables secundarias el flujo sanguíneo, Kt, y volumen total de reinfusión. En el segundo periodo se recogieron posibles complicaciones intradialíticas en el tiempo añadido.
Resultados: Se analizan 152 pacientes, 66% hombres, de 65,7 ± 14,9 (26-88) años de edad, con una permanencia en diálisis de 56,5 ± 59,5 meses, en un total de 1824 sesiones de hemodiafiltración on-line.
No se aprecian diferencias significativas en Qb (428,74±39,73 vs 429,86±38,54 ml/min).
El tiempo medio de la sesión aumenta significativamente (p
Nuestra experiencia con el catéter autoposicionante frente a otras variantes del catéter Tenckhoff. Estudio multicéntrico
Authors: Cirera Segura Francisco , Martín Espejo Jesús Lucas , Gómez Castilla Antonia Concepción , Ojeda Guerrero Mª Ángeles
Published: April 2013

Introducción: El objetivo del estudio fue comparar las complicaciones quirúrgicas, mecánicas e infecciosas que presenta el catéter autoposicionante frente a otros tipos de catéteres tipo Tenckhoff, así como comparar la supervivencia de ambos tipos de catéteres.
Material y métodos: Estudio descriptivo retrospectivo multicéntrico, de 79 meses de duración. Se estudiaron todos los catéteres colocados en dos unidades de diálisis peritoneal.
El análisis se realizó con el paquete estadístico IBM SPSS Statistics 19.0, estableciendo el nivel de significación en p
Extrusión del dacron en un catéter venoso central tunelizado para hemodiálisis
Authors: Crehuet Rodríguez Isabel , Méndez Briso-Montiano Pilar , Bernárdez-Lemus María Albina
Published: April 2013

El día a día del trabajo de la enfermería en las unidades de hemodiálisis (HD) nos demuestra la gran incidencia del uso de catéteres venosos centrales tunelizados como accesos vasculares para realizar dicha técnica. Estos catéteres, como todos sabemos, no están exentos de problemas con los que nos vamos encontrando más a menudo de lo que desearíamos (disfunciones por falta de flujo, aumento de presión venosa, etc.) y que afortunadamente conseguimos resolver antes de iniciar la sesión o durante la misma en la gran mayoría de ocasiones. Además de las complicaciones más graves como infecciones, trombosis1, etc. existe otra, no muy frecuente, pero no por ello menos importante, como es la extrusión del manguito (cuff) de dacron (en adelante dacron) en un catéter venoso central tunelizado. Según las recomendaciones existentes, requiere el recambio del catéter2, lo que se suele realizar de una manera sistemática, con mayor o menor prontitud, previa información y consentimiento del propio paciente; información y consentimiento regulados por la "Ley 41/2002, de 14 de Noviembre, básica reguladora de la autonomía del paciente y de derechos y obligaciones en materia de información y documentación clínica" ("...el paciente o usuario tiene derecho a decidir libremente después de recibir información adecuada entre las opciones clínicas disponibles")3. Se presentó en nuestra Unidad, un caso de extrusión del dacron en un catéter venoso tunelizado para HD, negándose la paciente a su sustitución, amparándose en la ley anteriormente citada.
The relative importance of impacts from climate change vs. emissions change on air pollution levels in the 21st century
Authors: Hedegaard G. B. , Christensen J. H. , Brandt J.
Published: April 2013

Abstract. So far several studies have analysed the impacts of climate change on future air pollution levels. Significant changes due to impacts of climate change have been made clear. Nevertheless, these changes are not yet included in national, regional or global air pollution reduction strategies. The changes in future air pollution levels are caused by both impacts from climate change and anthropogenic emission changes, the importance of which needs to be quantified and compared. In this study we use the Danish Eulerian Hemispheric Model (DEHM) driven by meteorological input data from the coupled Atmosphere-Ocean General Circulation Model ECHAM5/MPI-OM and forced with the newly developed RCP4.5 emissions. The relative importance of the climate signal and the signal from changes in anthropogenic emissions on the future ozone, black carbon (BC), total particulate matter with a diameter below 2.5 μm (total PM2.5 including BC, primary organic carbon (OC), mineral dust and secondary inorganic aerosols (SIA)) and total nitrogen (including NHx + NOy) has been determined. For ozone, the impacts of anthropogenic emissions dominate, though a climate penalty is found in the Arctic region and northwestern Europe, where the signal from climate change dampens the effect from the projected emission reductions of anthropogenic ozone precursors. The investigated particles are even more dominated by the impacts from emission changes. For black carbon the emission signal dominates slightly at high latitudes, with an increase up to an order of magnitude larger, close to the emission sources in temperate and subtropical areas. Including all particulate matter with a diameter below 2.5 μm (total PM2.5) enhances the dominance from emissions change. In contrast, total nitrogen (NHx + NOy) in parts of the Arctic and at low latitudes is dominated by impacts of climate change.
Arctic aerosol life cycle: linking aerosol size distributions observed between 2000 and 2010 with air mass transport and precipitation at Zeppelin station, Ny-Ålesund, Svalbard
Authors: Tunved P. , Ström J. , Krejci R.
Published: April 2013

Abstract. In this study we present a qualitative and quantitative assessment of more than 10 yr of aerosol number size distribution data observed in the Arctic environment (Mt. Zeppelin (78°56' N, 11°53' E, 474 m a.s.l.), Ny Ålesund, Svalbard). We provide statistics on both seasonal and diurnal characteristics of the aerosol observations and conclude that the Arctic aerosol number size distribution and related parameters such as integral mass and surface area exhibit a very pronounced seasonal variation. This seasonal variation seems to be controlled by both dominating source as well as meteorological conditions. Three distinctly different periods can be identified during the Arctic year: the haze period characterized by a dominating accumulation mode aerosol (March–May), followed by the sunlit summer period with low abundance of accumulation mode particles but high concentration of small particles which are likely to be recently and locally formed (June–August). The rest of the year is characterized by a comparably low concentration of accumulation mode particles and negligible abundance of ultrafine particles (September–February). A minimum in aerosol mass and number concentration is usually observed during September/October. We further show that the transition between the different regimes is fast, suggesting rapid change in the conditions defining their appearance. A source climatology based on trajectory analysis is provided, and it is shown that there is a strong seasonality of dominating source areas, with Eurasia dominating during the Autumn–Winter period and dominance of North Atlantic air during the summer months. We also show that new-particle formation events are rather common phenomena in the Arctic during summer, and this is the result of photochemical production of nucleating/condensing species in combination with low condensation sink. It is also suggested that wet removal may play a key role in defining the Arctic aerosol year, via the removal of accumulation mode size particles, which in turn have a pivotal role in facilitating the conditions favorable for new-particle formation events. In summary the aerosol Arctic year seems to be at least qualitatively predictable based on the knowledge of seasonality of transport paths and associated source areas, meteorological conditions and removal processes.
Top-down estimate of surface flux in the Los Angeles Basin using a mesoscale inverse modeling technique: assessing anthropogenic emissions of CO, NOx and CO2 and their impacts
Authors: Brioude J. , Angevine W. M. , Ahmadov R. , Kim S.-W. , Evan S. , McKeen S. A. , Hsie E.-Y. , Frost G. J. , Neuman J. A. , Pollack I. B. , Peischl J. , Ryerson T. B. , Holloway J. , Brown S. S. , Nowak J. B. , Roberts J. M. , Wofsy S. C. , Santoni G. W. , Oda T. , Trainer M.
Published: April 2013

Abstract. We present top-down estimates of anthropogenic CO, NOx and CO2 surface fluxes at mesoscale using a Lagrangian model in combination with three different WRF model configurations, driven by data from aircraft flights during the CALNEX campaign in southern California in May–June 2010. The US EPA National Emission Inventory 2005 (NEI 2005) was the prior in the CO and NOx inversion calculations. The flux ratio inversion method, based on linear relationships between chemical species, was used to calculate the CO2 inventory without prior knowledge of CO2 surface fluxes. The inversion was applied to each flight to estimate the variability of single-flight-based flux estimates. In Los Angeles (LA) County, the uncertainties on CO and NOx fluxes were 10% and 15%, respectively. Compared with NEI 2005, the CO posterior emissions were lower by 43% in LA County and by 37% in the South Coast Air Basin (SoCAB). NOx posterior emissions were lower by 32% in LA County and by 27% in the SoCAB. NOx posterior emissions were 40% lower on weekends relative to weekdays. The CO2 posterior estimates were 183 Tg yr−1 in SoCAB. A flight during ITCT (Intercontinental Transport and Chemical Transformation) in 2002 was used to estimate emissions in the LA Basin in 2002. From 2002 to 2010, the CO and NOx posterior emissions decreased by 41% and 37%, respectively, in agreement with previous studies. Over the same time period, CO2 emissions increased by 10% in LA County but decreased by 4% in the SoCAB, a statistically insignificant change. Overall, the posterior estimates were in good agreement with the California Air Resources Board (CARB) inventory, with differences of 15% or less. However, the posterior spatial distribution in the basin was significantly different from CARB for NOx emissions. WRF-Chem mesoscale chemical-transport model simulations allowed an evaluation of differences in chemistry using different inventory assumptions, including NEI 2005, a gridded CARB inventory and the posterior inventories derived in this study. The biases in WRF-Chem ozone were reduced and correlations were increased using the posterior from this study compared with simulations with the two bottom-up inventories, suggesting that improving the spatial distribution of ozone precursor surface emissions is also important in mesoscale chemistry simulations.
Evaluation of various methods to measure particulate bound mercury and associated artifacts
Authors: Wang S. , Holsen T. M. , Huang J. , Han Y.-J.
Published: April 2013

Abstract. This study was performed to determine how sampling artifacts associated with various sampling methods including open faced filter (OFF) pack, micro orifice uniform deposit impactor (MOUDI), and Tekran speciation system (TekSpec) impact particulate bound mercury (PBM) measurements. PBM measured by the MOUDI for 48 h was statistically lower than that measured with the TekSpec every 2 h, indicating that negative artifacts were significant for long sampling durations. Negative artifacts were also identified in lab experiments as the Hg0 and HgCl2 concentrations associated with particulate matter on the filter significantly decreased when the filter was exposed to zero air. Positive artifacts were also investigated. The OFF sampling for 48 h, which is likely to be associated with both positive and negative artifacts, measured a significantly lower PBM concentration than the TekSpec while the OFF and MOUDI (48 h sampling – minimal positive artifacts) showed similar results, suggesting that positive artifacts were minor under the rural condition encountered (low atmospheric gaseous oxidized mercury and typical oxidants concentrations). The Hg speciation associated with particles varied with atmospheric temperature, with the contribution of less volatile species including HgO and HgS increasing and more volatile Hg0 and HgCl2 decreasing as atmospheric temperature increased. There was significant correlation for PBM larger than 2.5 μm between TekSpec frit and MOUDI in this study, indicating that TekSpec frit is a good alternative sampler for measuring the concentration of coarse PBM.
Retrieval of the Eyjafjallajökull volcanic aerosol optical and microphysical properties from POLDER/PARASOL measurements
Authors: Waquet F. , Peers F. , Goloub P. , Ducos F. , Thieuleux F. , Derimian Y. , Riedi J. , Tanré D.
Published: April 2013

Abstract. Total and polarized radiances provided by the Polarization and Directionality of Earth Reflectances (POLDER) satellite sensor are used to retrieve the microphysical and optical properties of the volcanic plume observed during the Eyjafjallajökull volcano eruption in 2010, over cloud-free and cloudy ocean scenes. We selected two plume conditions, fresh aerosols near the sources (three cases) and a downwind volcanic plume observed over the North Sea 30 h after its injection into the atmosphere (aged aerosols). In the near-source conditions, the aerosol properties depend on the distance to the plume. Within the plume, aerosols are mainly non-spherical and in the coarse mode with an effective radius equal to 1.50 (± 0.15) μm and an Ångström Exponent (AE) close to 0.0. Far from the plume, in addition to the coarse mode, there are smaller particles retrieved in the accumulation mode suggesting a mixture of sulfate aerosols and volcanic dust, resulting in an AE around 0.8. The properties of the aerosols also depend on whether the plume is fresh or aged. For the downwind (aged) plume, if non-spherical coarse particles as well as some fine mode particles are still retrieved, the AE is smaller, around ~ 0.4. In addition, the real refractive index (RR) values are larger for the downwind plume (1.42 < RR < 1.58) than for the near-source plume (1.38 < RR < 1.48). The mean Single Scattering Albedo (SSA) retrieved at 0.865 μm was estimated at 0.97 over some parts of the downwind and near-source plumes; despite the low accuracy of our retrievals, the derived SSA values suggest that the ash particles are rather absorbing. To consider the particle shape, a combination of spheroid models is used. Although the employed model enabled accurate modeling of the POLDER signal in case of non-spherical ash, our approach failed to model the signal over the optically thickest parts of the near-source plume. The most probable reason for this is speculated to be the presence of ice crystals within the plume. For the Aerosol Above Clouds (AAC) scenes, polarized measurements allowed the retrieval of the Optical Thickness (OT) and the AE of optically thin volcanic ash. We found that all the cloud parameters retrieved by passive sensors were biased due to the presence of the elevated volcanic plumes. Finally, thermal infrared measurements were used to identify the type of multi-layer scene (i.e. cirrus clouds or volcanic dust above liquid clouds) and the retrieval method also provided the OT of thin cirrus layers above the clouds near Iceland.
Structure of ocean circulation between the Galápagos Islands and Ecuador
Authors: Collins C. , Mascarenhas A. , Martinez R.
Published: April 2013

Abstract. From 27 March to 5 April 2009, upper ocean velocities between the Galápagos Islands and Ecuador were measured using a vessel mounted ADCP. A region of possible strong cross-hemisphere exchange was observed immediately to the east of the Galápagos, where a shallow (200 m) 300 km wide northeastward surface flow transported 7–11 Sv. Underlying this strong northeastward surface current, a southward flowing undercurrent was observed which was at least 600 m thick, 100 km wide, and had an observed transport of 7–8 Sv. Next to the Ecuador coast, the shallow (< 200 m) Ecuador Coastal Current was observed to extend offshore 100 km with strongest flow, 0.33 m s−1, near the surface. Immediately to the west of the Ecuador Coastal Current, flow was directed eastward and southward into the beginnings of the Peru-Chile Countercurrent. The integral of the surface currents between the Galápagos and Ecuador agreed well with observed sea level differences. Although the correlation of the sea level differences with large scale climate indices (Niño3 and the Southern Oscillation Index) was significant, more than half of the sea level variability was not explained. Seasonal variability of the sea level difference indicated that sea level was 2 cm higher at the Galápagos during late winter and early spring, which could be associated with the pattern of northward surface flows observed by R/V Knorr.
ENSO impact on hydrology in Peru
Authors: Lavado-Casimiro W. S. , Felipe O. , Silvestre E. , Bourrel L.
Published: April 2013

Abstract. The El Niño and La Niña impacts on the hydrology of Peru were assessed based on discharge data (1968–2006) of 20 river catchments distributed over three drainage regions in Peru: 14 in the Pacific Coast (PC), 3 in the Lake Titicaca (TL) region, and 3 in the Amazonas (AM). To classify the El Niño and La Niña events, we used the Southern Oscillation Index (SOI) based on hydrological years (September to August). Using the SOI values, the events were re-classified as strong El Niño (SEN), moderate El Niño (MEN), normal years (N), moderate La Niña (MLN) and strong La Niña (SLN). On average during the SEN years, sharp increases occurred in the discharges in the north central area of the PC and decreases in the remaining discharge stations that were analyzed, while in the years of MEN events, these changes show different responses than those of the SEN. During the years classified as La Niña, positive changes are mostly observed in the majority of the stations in the rivers located in the center of Peru's Pacific Coast. Another important result of this work is that the Ilave River (south of the Titicaca watershed) shows higher positive (negative) impacts during La Niña (El Niño) years, a fact that is not clearly seen in the rivers of the northern part of the Titicaca watershed (Ramis and Huancane rivers).
Rainfall variability related to sea surface temperature anomalies in a Pacific–Andean basin into Ecuador and Peru
Authors: Pineda L. , Ntegeka V. , Willems P.
Published: April 2013

Abstract. The spatiotemporal modes of seasonal rainfall variability and their relation with sea surface temperature anomalies (SSTA 1.2 indices) are examined in the transition from the coastal plain towards the western Andes cordillera in southern Ecuador/northwestern Peru using instrumental records (1970–2000) collected from the Catamayo–Chira basin. A multi-criteria data analysis is conducted within different elevation ranges. The criteria involve rotated principal components, cross correlations and temporal changes of anomalies in rainfall quantiles. The results confirm that SSTA 1.2 indices influence rainfall variability over the coastal plain (< 510 m a.s.l.) where forcing is dominant within December–May. The El Niño Southern Oscillation also plays a role inland of the coastal plain where a region of ENSO-like rainfall variability is found on the southeastern part of the basin (4°30'–5° S/79°15'–80° W) within March–May (MAM). This suggests that inland distance and elevation are only partial controls of ocean–atmospheric forcing up to ~ 1300 m a.s.l. Our analysis also provides evidence of the SSTA 1.2 indices influence in a large altitudinal range ~ 1400–2700 m a.s.l. confined to the southeastern basin. This region is found consistently perturbed by ENSO within MAM. We conclude that geo-morphological features of the southwestern Ecuadorian Andean ridges play a twofold role in the control of ocean–atmospheric forcing. They can modulate the atmospheric circulation, leading to a dissipation of the signal, or they might favor meteorological processes, leading to enhancement of orographic precipitation. This would explain the observed ENSO signals in instrumental records at locations as high as 2700 m a.s.l.
Evaluation of the current state of small pelagic fisheries in the Colombian Pacific: ensuring the sustainability of the resource and evaluating its response to climatic events
Authors: Zapata L. A. , Beltrán-León B. S. , Herrera J. C. , Jiménez-Tello P. , Prieto L. M. , Baos R. A. , Guevara-Fletcher C. , Zambrano E.
Published: April 2013

Abstract. Commercial fishing of small pelagic species in Colombia, mainly "carduma" (Cetengraulis mysticetus) and "plumuda" (Opisthonema spp.), has been recorded since 1970. Both are used to produce fish meal for aquaculture and poultry and for canned foods. These two species are filter feeders, and therefore support higher levels of the food chain (other fish, birds and marine mammals), and artisanal fishermen use them as bait. Between 2005 and 2010, 86.131 t have been captured (X = 14.355 t yr−1), and a strong reduction was noticed in 2009 (6.969 t). Carduma is considered a total spawning species. However, from 1997 to 2000 and from 2008 to date, atypical reproductive behavior of the species has been observed, including partition of the spawning period and the reduction of the volume of eggs and larvae released to the environment. Both situations are linked to thermal anomalies such as El Niño and La Niña events. Therefore, the process of assigning the global quota of extraction has been revised to take into account the reduction of total capture during the last years and the inconsistencies of the reproductive processes. The Ministry of Agriculture reduced the quota by 10%, leaving available a total of 27 000 t for 2010 and reduced it again to 25 000 t for 2011. It is important to maintain the management measures that are already implemented on this resource (bans during reproduction seasons, catch quotas, regulation of mesh sizes for the fishing nets, and limiting the number of new vessels) and considering other measures such as season closure for recruitment and establishment of marine protected areas to further contribute to the sustainability of these fisheries.
Climate trends and projections for the Andean Altiplano and strategies for adaptation
Authors: Valdivia C. , Thibeault J. , Gilles J. L. , García M. , Seth A.
Published: April 2013

Abstract. Climate variability and change impact production in rainfed agricultural systems of the Bolivian highlands. Maximum temperature trends are increasing for the Altiplano. Minimum temperature increases are significant in the northern region, and decreases are significant in the southern region. Producers' perceptions of climate hazards are high in the central region, while concerns with changing climate and unemployment are high in the north. Similar high-risk perceptions involve pests and diseases in both regions. Altiplano climate projections for end-of-century highlights include increases in temperature, extreme event frequency, change in the timing of rainfall, and reduction of soil humidity. Successful adaptation to these changes will require the development of links between the knowledge systems of producers and scientists. Two-way participatory approaches to develop capacity and information that involve decision makers and scientists are appropriate approaches in this context of increased risk, uncertainty and vulnerability.
Global ocean storage of anthropogenic carbon
Authors: Khatiwala S. , Tanhua T. , Mikaloff Fletcher S. , Gerber M. , Doney S. C. , Graven H. D. , Gruber N. , McKinley G. A. , Murata A. , Ríos A. F. , Sabine C. L.
Published: April 2013

Abstract. The global ocean is a significant sink for anthropogenic carbon (Cant), absorbing roughly a third of human CO2 emitted over the industrial period. Robust estimates of the magnitude and variability of the storage and distribution of Cant in the ocean are therefore important for understanding the human impact on climate. In this synthesis we review observational and model-based estimates of the storage and transport of Cant in the ocean. We pay particular attention to the uncertainties and potential biases inherent in different inference schemes. On a global scale, three data-based estimates of the distribution and inventory of Cant are now available. While the inventories are found to agree within their uncertainty, there are considerable differences in the spatial distribution. We also present a review of the progress made in the application of inverse and data assimilation techniques which combine ocean interior estimates of Cant with numerical ocean circulation models. Such methods are especially useful for estimating the air–sea flux and interior transport of Cant, quantities that are otherwise difficult to observe directly. However, the results are found to be highly dependent on modeled circulation, with the spread due to different ocean models at least as large as that from the different observational methods used to estimate Cant. Our review also highlights the importance of repeat measurements of hydrographic and biogeochemical parameters to estimate the storage of Cant on decadal timescales in the presence of the variability in circulation that is neglected by other approaches. Data-based Cant estimates provide important constraints on forward ocean models, which exhibit both broad similarities and regional errors relative to the observational fields. A compilation of inventories of Cant gives us a "best" estimate of the global ocean inventory of anthropogenic carbon in 2010 of 155 ± 31 PgC (±20% uncertainty). This estimate includes a broad range of values, suggesting that a combination of approaches is necessary in order to achieve a robust quantification of the ocean sink of anthropogenic CO2.
Climate and land use change impacts on global terrestrial ecosystems, fire, and river flows in the HadGEM2-ES Earth System Model using the Representative Concentration Pathways
Authors: Betts R. A. , Golding N. , Gonzalez P. , Gornall J. , Kahana R. , Kay G. , Mitchell L. , Wiltshire A.
Published: April 2013

Abstract. A new generation of an Earth System Model now includes a number of land surface processes directly relevant to analyzing potential impacts of climate change. This model, HadGEM2-ES, allows us to assess the impacts of climate change, multiple interactions, and feedbacks as the model is run. This paper discusses the results of century-scale HadGEM2-ES simulations from an impacts perspective–specifically, terrestrial ecosystems and water resources–for four different scenarios following the Representative Concentration Pathways (RCPs), being used for next assessment report of the Intergovernmental Panel on Climate Change (IPCC). Over the 21st Century, simulated changes in global and continential-scale terrestrial ecosystems due to climate change appear to be very similar in all 4 RCPs, even though the level of global warming by the end of the 21st Century ranges from 2 °C in the lowest scenario to 5.5° in the highest. A warming climate generally favours broadleaf trees over needleleaf, needleleaf trees over shrubs, and shrubs over herbaceous vegetation, resulting in a poleward shift of temperate and boreal forests and woody tundra in all scenarios. Although climate related changes are slightly larger in scenarios of greater warming, the largest differences between scenarios arise at regional scales as a consequence of different patterns of anthropogenic land cover change. In the model, the scenario with the lowest global warming results in the most extensive decline in tropical forest cover due to a large expansion of agriculture. Under all four RCPs, fire potential could increase across extensive land areas, particularly tropical and sub-tropical latitudes. River outflows are simulated to increase with higher levels of CO2 and global warming in all projections, with outflow increasing with mean temperature at the end of the 21st Century at the global scale and in North America, Asia, and Africa. In South America, Europe, and Australia, the relationship with climate warming and CO2 rise is less clear, probably as a result of land cover change exerting a dominant effect in those regions.
Post-Pliocene establishment of the present monsoonal climate in SW China: evidence from the late Pliocene Longmen megaflora
Authors: Su T. , Jacques F. M. B. , Spicer R. A. , Liu Y.-S. , Huang Y.-J. , Xing Y.-W. , Zhou Z.-K.
Published: April 2013

Abstract. The paleoclimate of the late Pliocene Longmen flora from Yongping County located at the southeastern boundary of the Qinghai-Tibet Plateau was reconstructed using two leaf physiognomy based methods, i.e. Leaf Margin Analysis (LMA) and Climate Leaf Analysis Multivariate Program (CLAMP), to understand the paleoclimate condition and geographical pattern of monsoonal climate in southwestern China during the late Pliocene. The mean annual temperatures (MATs) estimated by LMA and CLAMP are 17.4 ± 3.3 °C and 17.4 ± 1.3 °C, respectively, compared with 15.9 °C at present. Meanwhile, the growing season precipitation (GSP) estimated by CLAMP is 1735.5 ± 217.7 mm in the Longmen flora, compared with 986.9 mm nowadays. The calculated monsoon index (MSI) of the Longmen flora is significantly lower than that of today. These results appear consistent with previous studies based on the coexistence approach (CA), and further suggest that there was a slightly warmer and much wetter climate during the late Pliocene than the present climate in western Yunnan. We conclude that the significant change of the monsoonal climate might have been resulted from the continuous uplift of mountains in western Yunnan, as well as the intensification of eastern Asian winter monsoon, both occurring concurrently in the post-Pliocene period.
Multivariate return periods in hydrology: a critical and practical review focusing on synthetic design hydrograph estimation
Authors: Gräler B. , van den Berg M. J. , Vandenberghe S. , Petroselli A. , Grimaldi S. , De Baets B. , Verhoest N. E. C.
Published: April 2013

Abstract. Most of the hydrological and hydraulic studies refer to the notion of a return period to quantify design variables. When dealing with multiple design variables, the well-known univariate statistical analysis is no longer satisfactory, and several issues challenge the practitioner. How should one incorporate the dependence between variables? How should a multivariate return period be defined and applied in order to yield a proper design event? In this study an overview of the state of the art for estimating multivariate design events is given and the different approaches are compared. The construction of multivariate distribution functions is done through the use of copulas, given their practicality in multivariate frequency analyses and their ability to model numerous types of dependence structures in a flexible way. A synthetic case study is used to generate a large data set of simulated discharges that is used for illustrating the effect of different modelling choices on the design events. Based on different uni- and multivariate approaches, the design hydrograph characteristics of a 3-D phenomenon composed of annual maximum peak discharge, its volume, and duration are derived. These approaches are based on regression analysis, bivariate conditional distributions, bivariate joint distributions and Kendall distribution functions, highlighting theoretical and practical issues of multivariate frequency analysis. Also an ensemble-based approach is presented. For a given design return period, the approach chosen clearly affects the calculated design event, and much attention should be given to the choice of the approach used as this depends on the real-world problem at hand.