bluuebunny/crossref_metadata_2025 huggingface dataset:
Permian and triassic stratigraphy of Mackenzie delta, and the British, Barn, and Richardson mountains, Yukon and Northwest Territories
Authors: Dixon J
Published: March 2016

Permian strata in the British and Richardson mountains and in the subsurface of Mackenzie Delta have a similar, threefold division. A variably thick, basal, generally sandstone-dominant interval is abruptly overlain by a thick, shale-dominated succession, which
is in turn gradationally to abruptly overlain by a sandstone-rich succession. In the British Mountains, these beds are correlated with the Echooka Formation of the Sadlerochit Group, whereas in the Richardson Mountains and Mackenzie Delta, the lower two successions are correlated with the Jungle
Creek Formation and divided into a Lower and Upper member. The upper, sandstone-rich succession in the Richardson Mountains and adjacent subsurface, is herein named the Longstick Formation.
Most of the Permian succession is of marine shelf origin, with the exception of parts of the Lower member, especially in the eastern Richardson Mountains and parts of the adjacent subsurface, where nonmarine, alluvial fan, fan-delta, and braided river deposits are present.
Triassic strata generally are thin, areally restricted, and are present at scattered locations. In the British Mountains, the upper part of the succession previously identified as the Sadlerochit Group is inferred to be part of the Lower Triassic Ivishak Formation. The only other known occurrence of
Lower Triassic strata is an isolated exposure in the northern Richardson Mountains. The bulk of the known Triassic strata is Carnian and Norian (Upper Triassic) in age, with the latter being more common. These Upper Triassic strata are correlated with the Shublik Formation and are present primarily
in the British Mountains, in a few scattered outliers in the Barn Mountains, and to the east of the central Richardson Mountains, at Salter Hill. The Triassic consists of a mixture of siliciclastic and carbonate beds, and is marine at all of its known occurrences.
Major discontinuities in the Permian succession are not readily identified, although there is some minor physical evidence to suggest that, locally, the lower contact of the Longstick Formation may be disconformable. On the other hand, the Triassic can be divided into a number of
unconformity-bounded successions.
The economic potential of Permian and Triassic strata is considered to be minimal. No mineral showings are known in either succession. Although thermal indicators indicate oil generation is possible in the subsurface succession of Mackenzie Delta, no Permian source rocks have been identified.
Reservoir- quality beds are not very common in the Permian.
3D hydrostratigraphic modelling of the Paleozoic bedrock of southern Ontario
Authors: Carter T R , Brunton F R , Clark J , Fortner L , Hamblin A , Logan C , Russell H A J
Published: March 2016

The Geological Survey of Canada, the Ontario Geological Survey, the Ministry of Natural Resources and Forestry and the Ontario Oil, Gas and Salt Resources (OGSR) Library have initiated a cooperative project to create a regional 3D model of the layered Paleozoic
bedrock strata of southern Ontario, and the occurrence of water within these strata.
A wealth of data are available, including digital records from 400,000 water wells that penetrate the bedrock, nearly 27,000 petroleum wells records, and approximately 300 stratigraphic boreholes in shallow bedrock formations completed by the Ontario Geological Survey. Petroleum well records are the
key data source for the model, with data already coded in an Oracle relational database with geographic coordinates and elevation data for all wells. There are depth and elevation values for nearly 600,000 formation tops and over 35,000 water interval records with information on water type, depth
interval and static level. A significant number of QC edits has greatly improved accuracy and reliability of this data set since 2001, with further improvements to be funded by the GSC as part of this project. Also available are compositional analyses for over 1000 samples of produced water from
petroleum wells, isotopic and compositional analyses for 130 samples of deep to intermediate groundwater, 89 water type maps and 17 static level maps for deep groundwater aquifers, and field observations from springs, quarries, road cuts, outcrops, well testing, and drill core examinations.
The model will incorporate and build on a published regional 2D conceptual model of groundwater systems in the bedrock of southern Ontario, documenting a hydrochemical zonation of water by depth into a shallow fresh water system, an intermediate sulphur water system and a deep brine system.
Hydrostratigraphic units in the southern Ontario bedrock are known to cross formational boundaries. Hydrostratigraphic units also change character laterally, within the same formation, due to facies changes, diagenetic modification, faulting and, of particular significance in southern Ontario,
karstification of carbonate or evaporite strata at unconformities. Paleokarst horizons are known to be a key geological control on aquifers in the bedrock. Modelling of this inhomogeneity is a complex technical and conceptual task and will comprise an iterative process of modelling, QA/QC data
review and editing, and critical geological appraisal.
Final products will be co-released by GSC and the OGS with access via the OGSR Library website, and will include a 3D model in both Leapfrog and ESRI ArcGIS formats, a 2D conceptual hydrostratigraphic model, and improvements in data quality and accuracy in the petroleum well database. Numeric
groundwater flow modelling is beyond the scope of this project but the static model will support dynamic modelling. Target date for project completion is mid to late 2018.
Remote sensing activities in Southern Ontario in NRCan/ESS Groundwater Geoscience Program
Authors: Wang S , Li J
Published: March 2016

Water resources and their sustainability/vulnerability are determined by climate, physiography conditions of land surface and aquifers, and human activities. Satellite remote sensing can contribute to a better understanding of water resources in various ways. In
this talk, three activities associated with remote sensing in the NRCan/ESS Groundwater Geoscience Program will be discussed. The first activity (1) is water cycle modelling and water budget assessment. This activity involves modelling the various water fluxes and storages in the
atmosphere-vegetation-soil-aquifer system. It relies on the ESS land surface model EALCO and remote sensing products, as well as a number of other datasets for climate, soil and aquifers. Major outputs include evapotranspiration, surface runoff, snow cover, soil water, diffuse recharge and discharge
of groundwater, etc. The model provides a platform to integrate the physical water processes with satellite observations, and to study water sustainability/vulnerability issues associated with climate change and human disturbances. The second activity (2) is soil moisture mapping. This activity aims
at downscaling SMOS/SMAP soil moisture products (40-50km) using Radarsat-2 data to produce soil moisture map at a higher resolution (5-10km). The method includes removing the effect of vegetation using the water-cloud model and the effect of soil surface roughness using multi-temporal Radarsat-2
data. The wavelet transform is combined with the water-cloud model in soil moisture downscaling. The third activity (3) is characterising water storage variations using Radarsat-2 InSAR data and microgravity measurements. InSAR has been proven to be an efficient technique for measuring surface
deformation. This activity investigates the potential of using an inversion model of surface deformation to characterise water storage variations. Field microgravity and GPS measurements over the Waterloo Moraine were also conducted to investigate the potential for using gravity signal to
characterise water storage. Activity (1) aims at modelling the water cycle through integrating multiple remote sensing products that are available. Activities (2) and (3) are expected to generate new/improved water-related variables from remote sensing, which can be used in Activity (1) to further
constrain the water modelling so that our understanding of the water can be improved.
The role of cardiac CT angiography in the pre- and postoperative evaluation of tetralogy of Fallot
Authors: Banderker Ebrahim , Pretorius Elias , De Decker Rik
Published: March 2016

Tetralogy of Fallot (TOF) is the first described and most common cyanotic congenital heart anomaly that generated the first successful surgical palliation procedure and definitive intracardiac repair. Classical TOF comprises the four typical features of right ventricular outflow tract obstruction (RVOTO), right ventricular hypertrophy (RVH), ventricular septal defect (VSD) and aortic dextroposition. Complex forms of the condition include TOF associated with absent pulmonary valve and TOF with pulmonary atresia (TOF-PA) with or without major aortopulmonary collateral arteries (MAPCAs). The pathophysiological understanding that the tetrad is basically the sequel of a singular abnormality of infundibular malformation, with anterior deviation of the infundibular septum, had major surgical consequences that improved survival. Diagnostic and functional imaging play a key role in the clinical and surgical management of patients with TOF. We revisit the role of traditionally employed imaging modalities (echocardiography and cardiac catheterisation) only briefly as these remain within the domain of cardiology practice. The emphasis of the present review is to outline the role of cardiac computed tomographic angiography (CTA) in the evaluation of TOF, with special reference to the technical considerations and best practice recommendations. Cardiovascular magnetic resonance imaging (CMR) is addressed only in passing, as this service is not currently available at our institution.
The Dirichlet Problem for the Slab with Entire Data and a Difference Equation for Harmonic Functions
Authors: Khavinson Dmitry , Lundberg Erik , Render Hermann
Published: March 2016

It is shown that the Dirichlet problem for the slab (a, b) × ℝd with entire boundary data has an entire solution. The proof is based on a generalized Schwarz reflection principle. Moreover, it is shown that for a given entire harmonic function g, the inhomogeneous difference equation h(t + 1, y) − h(t, y) = g(t, y) has an entire harmonic solution h.
Differences in Liver Impairment Between Adults and Children with Dengue Infection
Authors: Martínez Vega Rosario , Phumratanaprapin Weerapong , Phonrat Benjaluck , Dhitavat Jittima , Sutherat Maleerat , Choovichian Vorada
Published: March 2016

Dengue infection (DI) is a major vector-borne disease in southeast Asia and an important cause of morbidity. The complications such as hepatic impairment are common, and because the physiology of the liver differs between children and adults, the DI-associated liver impairments might be expected to differ as well. This study aims to compare the differences in liver impairment between adults and children with DI. We retrospectively studied 158 adults and 79 children with serologically confirmed DI admitted to the Bangkok Hospital for Tropical Diseases from 2008 to 2012. In total, 93% of adults and 87% of children exhibited abnormal liver enzyme levels during hospitalization. Overall, 76 (42.4%) adults and 16 (20.3%) children had dengue hemorrhagic fever (DHF). Compared with children, adults with dengue fever (DF) presented a significantly higher incidence of liver function impairment (alanine transaminase [ALT] > 2 × upper limit of normal [ULN]) (47.1% versus 25.5%), hepatitis (ALT > 4 × ULN) (29.4% versus 12.8%), and severe hepatitis (aspartate transaminase [AST]/ALT > 10 × ULN) (16.5% versus 4.3%). Children with DHF showed a significantly higher incidence of liver function impairment due to AST derangement than did adults (100% versus 73%). There were no differences in the total bilirubin, albumin, or total protein levels between adults and children. Liver enzymes normalized significantly more slowly in adults, and AST recovery was faster than ALT. In conclusion, liver function impairment was more common among adults than children with DF. As the severity progressed to DHF, liver injury became more common in children.
Local Production of a Liquid Direct Agglutination Test as a Sustainable Measure for Control of Visceral Leishmaniasis in Sudan
Authors: Osman Hussam Ali , Mahamoud Abdelhafeiz , Abass Elfadil Mustafa , Madi Rubens Riscala , Semiao-Santos Saul J. , el Harith Abdallah
Published: March 2016

A prerequisite for the control of visceral leishmaniasis (VL) is the accessibility to reference diagnostics. The high price of the freeze-dried direct agglutination test (FD-DAT) and the short shelf-life time of the rK39 strip test (rK39) have limited the application of these tests in Sudan. An original liquid DAT (LQ-DAT) with high reproducibility compared with the FD-DAT and rK39 has been routinely produced in our laboratory since 1999. In this study, a 3.4-year-old batch (of more than 90 test batches produced to date) was chosen to validate the diagnostic performance of this test against microscopy, FD-DAT, and rK39 in 96 VL and 42 non-VL serum samples. Relatively higher sensitivity (95/96, 99.0%) was recorded for the LQ-DAT than for the FD-DAT (92/96, 95.8%) and rK39 (76/96, 79.2%), probably because of the use of the endemic autochthonous Leishmania donovani isolate as the antigen. Experience with the LQ-DAT, its low cost of production, ease of providing this test, and diagnostic reliability compared with the FD-DAT suggest that widescale implementation of the LQ-DAT can contribute to sustainable VL control in Sudan.
Chikungunya and Dengue Virus Infections Among United States Community Service Volunteers Returning from the Dominican Republic, 2014
Authors: Millman Alexander J. , Esposito Douglas H. , Biggs Holly M. , Decenteceo Michelle , Klevos Andrew , Hunsperger Elizabeth , Munoz-Jordan Jorge , Kosoy Olga I. , McPherson Heidi , Sullivan Carmen , Voorhees Dayton , Baron David , Watkins Jim , Gaul Linda , Sotir Mark J. , Brunette Gary , Fischer Marc , Sharp Tyler M. , Jentes Emily S.
Published: March 2016

Chikungunya spread throughout the Dominican Republic (DR) after the first identified laboratory-confirmed cases were reported in April 2014. In June 2014, a U.S.-based service organization operating in the DR reported chikungunya-like illnesses among several staff. We assessed the incidence of chikungunya virus (CHIKV) and dengue virus (DENV) infection and illnesses and evaluated adherence to mosquito avoidance measures among volunteers/staff deployed in the DR who returned to the United States during July–August 2014. Investigation participants completed a questionnaire that collected information on demographics, medical history, self-reported illnesses, and mosquito exposures and avoidance behaviors and provided serum for CHIKV and DENV diagnostic testing by reverse transcription polymerase chain reaction and IgM enzyme-linked immunosorbent assay. Of 102 participants, 42 (41%) had evidence of recent CHIKV infection and two (2%) had evidence of recent DENV infection. Of the 41 participants with evidence of recent CHIKV infection only, 39 (95%) reported fever, 37 (90%) reported rash, and 37 (90%) reported joint pain during their assignment. All attended the organization's health trainings, and 89 (87%) sought a pretravel health consultation. Most (∼95%) used insect repellent; however, only 30% applied it multiple times daily and < 5% stayed in housing with window/door screens. In sum, CHIKV infections were common among these volunteers during the 2014 chikungunya epidemic in the DR. Despite high levels of preparation, reported adherence to mosquito avoidance measures were inconsistent. Clinicians should discuss chikungunya with travelers visiting areas with ongoing CHIKV outbreaks and should consider chikungunya when diagnosing febrile illnesses in travelers returning from affected areas.
Spatial–Temporal Co-Circulation of Dengue Virus 1, 2, 3, and 4 Associated with Coinfection Cases in a Hyperendemic Area of Brazil: A 4-Week Survey
Authors: Andrade Elisa H. P. , Figueiredo Leandra B. , Vilela Ana P. P. , Rosa Júlio C. C. , Oliveira Jaquelline G. , Zibaoui Hassan M. , Araújo Valdelaine E. M. , Miranda Daniela P. J. , Ferreira Paulo C. P. , Abrahão Jonatas S. , Kroon Erna G.
Published: March 2016

Dengue is currently regarded as a major public health problem worldwide. In a hyperendemic region during an outbreak, we detected the co-circulation of all Dengue virus (DENV) serotypes including two different genotypes of DENV-3 and DENV-4, and concurrent infections with up to three serotypes were identified in symptomatic patients. A total of 49 acute phase plasma samples from patients clinically suspected of dengue were collected during the 4 weeks of May 2013. DENV-1-4 was detected by reverse transcriptase semi-nested polymerase chain reaction in 33 samples (67.3%), of which 26 DNA fragments were sequenced. Twenty samples (76.9%) were identified with a single DENV serotype and six (23.1%) with more than one serotype. DENV-3 was the predominant serotype of the outbreak. On the basis of phylogenetic analyses, DENV-1 isolates belong to genotype V, DENV-2 to American–Asian genotype, DENV-3 to genotypes I and III, and DENV-4 to genotypes I and II.
Disseminated Histoplasmosis with Skin Lesions and Osteomyelitis in a Patient from the Philippines
Authors: Azar Marwan M. , Malinis Maricar F.
Published: March 2016

Histoplasmosis, caused by the dimorphic fungus Histoplasma capsulatum, is a disease of protean manifestations and of global distribution. Although increasingly reported in Asia, there are few reports from the Philippines. Here, we describe a case of microbiologically diagnosed histoplasmosis, probably acquired from the Philippines, in a returning traveler who presented with a right foot wound and papular rash. The final diagnosis was disseminated histoplasmosis with cutaneous and bone involvement, both unusual manifestations of the disease.
Evaluating the spatio-temporal performance of sky-imager-based solar irradiance analysis and forecasts
Authors: Schmidt Thomas , Kalisch John , Lorenz Elke , Heinemann Detlev
Published: March 2016

Abstract. Clouds are the dominant source of small-scale variability in surface solar radiation and uncertainty in its prediction. However, the increasing share of solar energy in the worldwide electric power supply increases the need for accurate solar radiation forecasts. In this work, we present results of a very short term global horizontal irradiance (GHI) forecast experiment based on hemispheric sky images. A 2-month data set with images from one sky imager and high-resolution GHI measurements from 99 pyranometers distributed over 10 km by 12 km is used for validation. We developed a multi-step model and processed GHI forecasts up to 25 min with an update interval of 15 s. A cloud type classification is used to separate the time series into different cloud scenarios. Overall, the sky-imager-based forecasts do not outperform the reference persistence forecasts. Nevertheless, we find that analysis and forecast performance depends strongly on the predominant cloud conditions. Especially convective type clouds lead to high temporal and spatial GHI variability. For cumulus cloud conditions, the analysis error is found to be lower than that introduced by a single pyranometer if it is used representatively for the whole area in distances from the camera larger than 1–2 km. Moreover, forecast skill is much higher for these conditions compared to overcast or clear sky situations causing low GHI variability, which is easier to predict by persistence. In order to generalize the cloud-induced forecast error, we identify a variability threshold indicating conditions with positive forecast skill.
An evaluation of IASI-NH3 with ground-based FTIR measurements
Authors: Dammers Enrico , Palm Mathias , Van Damme Martin , Vigouroux Corinne , Smale Dan , Conway Stephanie , Toon Geoffrey C. , Jones Nicholas , Nussbaumer Eric , Warneke Thorsten , Petri Christof , Clarisse Lieven , Clerbaux Cathy , Hermans Christian , Lutsch Erik , Strong Kim , Hannigan James W. , Nakajima Hideaki , Morino Isamu , Herrera Beatriz , Stremme Wolfgang , Grutter Michel , Schaap Martijn , Wichink Kruit Roy J. , Notholt Justus , Coheur Pierre-F. , Erisman Jan Willem
Published: March 2016

Abstract. Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground based instruments. Due to their large spatial coverage and daily observations, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions, and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface observations without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier Transform InfraRed (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008–2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (Nobs = 547) give a MRD of −32.4 ± (56.3) %, a correlation r of 0.8 with a slope of 0.73. These results indicate that the IASI-NH3 product performs better than previous upper bound estimates (-50% – +100 %).
The natural oscillations in stratospheric ozone observed by the GROMOS microwave radiometer at the NDACC station Bern
Authors: Moreira Lorena , Hocke Klemens , Navas-Guzmán Francisco , Eckert Ellen , von Clarmann Thomas , Kämpfer Niklaus
Published: March 2016

Abstract. A multilinear parametric regression analysis was performed to assess the seasonal and inter-annual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) microwave radiometer at Bern, Switzerland (46.95°N, 7.44°E, 577 m). GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC). The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km) and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO), the quasi-biennial oscillation (QBO), the El Niño-Southern Oscillation (ENSO) and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the inter-annual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern mid-latitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5% for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose that the strong amplitude is partly due to meteorological disturbances and associated ozone anomalies in the Northern hemisphere. Further, our observational study gave the result that ozone above Bern is anti-correlated to the ENSO phenomenon in the lower stratosphere and correlated in the middle stratosphere.
Optimal use of buffer volumes for the measurement of atmospheric gas concentration in multi-point systems
Authors: Cescatti Alessandro , Marcolla Barbara , Goded Ignacio , Gruening Carsten
Published: March 2016

Abstract. Accurate multi-point monitoring systems are required to derive atmospheric measurements of greenhouse gas concentrations both for the calculation of surface fluxes with inversion transport models and for the estimation of non-turbulent components of the mass balance equation (i.e. advection and storage fluxes) at eddy covariance sites. When a single analyser is used to monitor multiple sampling points, the deployment of buffer volumes (BV) along sampling lines can reduce the uncertainty due to the discrete temporal sampling of the signal. In order to optimize the use of buffer volumes we explored various setups by simulating their effect on time series of high-frequency CO2 concentration collected at three Fluxnet sites. Besides, we proposed a novel scheme to calculate half hourly weighted averages from discrete point samples, accounting for the probabilistic fraction of the signal generated in the averaging period. Results show that the use of BV with the new averaging scheme reduces the mean absolute errors (MAE) up to 80 % compared to set-up without BV and up to 60 % compared to the case with BV and a standard, non-weighted averaging scheme. The MAE of CO2 concentration measurements was observed to depend on the variability of the concentration field and on the size of BV, which therefore have to be carefully dimensioned. The optimal volume size depends on two main features of the instrumental setup: the number of measurement points and the time needed to sample at one point (i.e. line purging plus sampling time). A linear and consistent relationship was observed at all sites between the sampling frequency, which summarizes the two features mentioned above, and the renewal frequency associated to the volume. Ultimately, this empirical relationship can be applied to estimate the optimal volume size according to the technical specifications of the sampling system.
A novel single-cavity multi-wavelength photoacoustic spectrometer for atmospheric aerosol research
Authors: Linke Claudia , Ibrahim Inas , Schleicher Nina , Hitzenberger Regina , Andreae Meinrat O. , Leisner Thomas , Schnaiter Martin
Published: March 2016

Abstract. The spectral light absorbing behavior of carbonaceous aerosols varies depending on the chemical composition and structure of the particles. A new single-cavity multi-wavelength photoacoustic spectrometer was developed and characterized for measuring absorption coefficients at three wavelengths across the visible spectral range. In laboratory studies, several types of soot with different organic content were generated by a diffusion flame burner and were investigated for changes in mass-specific absorption cross sections (MAC), absorption and scattering Ångström exponents (αabs and αsca), and single scattering albedo (ω). By increasing the organic carbonaceous (OC) content of the aerosol from 50 % to 90 % of the total carbonaceous mass, for 660 nm nearly no change of MAC was found with increasing OC content. In contrast, for 532 nm a significant, and for 445 nm a strong increase of MAC was found with increasing OC content of the aerosol. Depending on the OC content, the Ångström exponents of absorption and scattering as well as the single scattering albedo increased. These laboratory results were compared to a field study at a traffic dominated urban site, which was also influenced by residential wood combustion. For this site a daily average value of αabs(445–660) of 1.9 was found.
Quantitative sediment source attribution with compound-specific isotope analysis in a C3 plant-dominated catchment (central Switzerland)
Authors: Alewell Christine , Birkholz Axel , Meusburger Katrin , Schindler Wildhaber Yael , Mabit Lionel
Published: March 2016

Abstract. As sediment loads impact freshwater systems and infrastructure, their origin in complex landscape systems is of crucial importance for sustainable management of agricultural catchments. We differentiated the sediment source contribution to a lowland river in central Switzerland by using compound-specific isotope analysis (CSIA). We found a clear distinction of sediment sources originating from forest and agricultural land use. Our results demonstrate that it is possible to reduce the uncertainty of sediment source attribution in: (i) using compound content (in our case, long-chain fatty acids; FAs) rather than soil organic matter content to transfer δ13C signal of FAs to soil contribution and (ii) restricting the investigation to the long-chain FAs (> C22 : 0) not to introduce errors due to aquatic contributions from algae and microorganisms. Results showed unambiguously that during base flow, agricultural land contributed up to 65 % of the suspended sediments, while forest was the dominant sediment source during high flow. This indicates that connectivity of sediment source areas within the river changes between base and high flow conditions. Uncertainty, which might occur in complex, large-scale studies due to undetected source attribution and/or CSSI signature degradation, is low because of limited data complexity in our study (i.e., two–three sources and two tracers). Our findings are the first published results highlighting (i) significant differences in compound-specific stable isotope (CSSI) signature of sediment sources from land uses dominated by C3 plant cultivation and (ii) the use of these differences to quantify sediment contribution to a small river.
Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea
Authors: Rovelli Lorenzo , Dengler Marcus , Schmidt Mark , Sommer Stefan , Linke Peter , McGinnis Daniel F.
Published: March 2016

Abstract. In recent decades, the central North Sea has been experiencing a general trend of decreasing dissolved oxygen (O2) levels during summer. To understand potential causes driving lower O2, we investigated a 3-day period of summertime turbulence and O2 dynamics in the thermocline and bottom boundary layer (BBL). The study focuses on coupling biogeochemical with physical transport processes to identify key drivers of the O2 and organic carbon turnover within the BBL. Combining our flux observations with an analytical process-oriented approach, we resolve drivers that ultimately contribute to determining the BBL O2 levels. We report substantial turbulent O2 fluxes from the thermocline into the otherwise isolated bottom water attributed to the presence of a baroclinic near-inertial wave. This contribution to the local bottom water O2 and carbon budgets has been largely overlooked and is shown to play a role in promoting high carbon turnover in the bottom water while simultaneously maintaining high O2 concentrations. This process may become suppressed with warming climate and stronger stratification, conditions which could promote migrating algal species that potentially shift the O2 production zone higher up within the thermocline.
Chemodiversity of Dissolved Organic Matter in the Amazon Basin
Authors: Gonsior Michael , Valle Juliana , Schmitt-Kopplin Philippe , Hertkorn Norbert , Bastviken David , Luek Jenna , Harir Mourad , Bastos Wanderley , Enrich-Prast Alex
Published: March 2016

Abstract. Regions in the Amazon Basin have been associated with specific biogeochemical processes, but a detailed chemical classification of the abundant and ubiquitous dissolved organic matter (DOM), beyond specific indicator compounds and bulk measurements, has not yet been established. We sampled water from different locations in the Negro, Madeira/Jamari and Tapajós River areas to characterize the molecular DOM composition and distribution. Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) combined with excitation emission matrix (EEM) fluorescence spectroscopy and Parallel Factor Analysis (PARAFAC) revealed a large proportion of ubiquitous DOM but also unique area-specific molecular signatures. Unique to the DOM of the Rio Negro area was the large abundance of high molecular weight, diverse hydrogen-deficient and highly oxidized molecular ions deviating from known lignin or tannin compositions, indicating substantial oxidative processing of these ultimately plant-derived polyphenols indicative of these black waters. In contrast, unique signatures in the Madeira/Jamari area were defined by presumably labile sulfur and nitrogen-containing molecules in this white water river system. Waters from the Tapajós confluence area did not show any substantial unique molecular signatures relative to those present in the Rio Madeira and Rio Negro, which implied a lower organic molecular complexity in this clear water tributary. Beside ubiquitous DOM at average H/C and O/C elemental ratios, a distinct and significant unique DOM pool prevailed in the black, white and clear water areas that were also highly correlated with EEM-PARAFAC components and define the frameworks for primary production and other aspects of aquatic life.
Coccolithophore responses to environmental variability in the South China Sea: species composition and calcite content
Authors: Jin X. B. , Liu C. L. , Poulton A. J. , Dai M. H. , Guo X. H.
Published: March 2016

Abstract. Coccolithophore contributions to the global marine carbon cycle are regulated by the calcite content of their scales (coccoliths), and the relative cellular levels of photosynthesis and calcification. All three of these factors vary between coccolithophore species, and with response to the growth environment. Here, water samples were collected in the northern basin of the South China Sea (SCS) during summer 2014 in order to examine how environmental variability influenced species composition and cellular levels of calcite content. The vertical structure of the coccolithophore community was strongly regulated by mesoscale eddies. All living coccolithophores produced within the euphotic zone (1 % of surface irradiance), and Florisphaera profunda was a substantial coccolithophore and coccolith-calcite producer in the Deep Chlorophyll-a Maximum (DCM), especially in most oligotrophic anti-cyclonic eddy centers. Placolith-bearing coccolithophores, plus F. profunda, and other larger and numerically rare species made almost equal contributions to coccolith-based calcite in the water column. For Emiliania huxleyi biometry measurements, coccolith size positively correlated with nutrients, and it is suggested that coccolith length is influenced by nutrient and light related growth rates. However, larger sized coccoliths were related to low pH and calcite saturation, although it is not a simple cause and effect relationship. Genotypic or ecophenotypic variation may also be linked to coccolith size variation.
Assessing uncertainties in global cropland futures using a conditional probabilistic modelling framework
Authors: Engström Kerstin , Olin Stefan , Rounsevell Mark D. A. , Brogaard Sara , van Vuuren Detlef P. , Alexander Peter , Murray-Rust Dave , Arneth Almut
Published: March 2016

Abstract. We present a SSP-RCP modelling framework to simulate conditional probabilistic futures of global cropland areas. Simulations are based on the Parsimonious Land Use Model (PLUM) linked with the global dynamic vegetation model LPJ-GUESS using climate and socio-economic data from the RCPs (Representative Concentration Pathways) and the SSPs (Shared Socio-economic Pathways). For the assumptions made in this study, the simulated range of global cropland is 893-2380 Mha in 2100 (± one standard deviation). The main uncertainties in these projections arise from differences in the socio-economic conditions prescribed by the SSP scenarios, and the assumptions that underpin the translation of qualitative SSP storylines into quantitative model input parameters. Uncertainty in the assumptions for population growth, technological change and cropland degradation were found to be the most important for global cropland, while uncertainty in food consumption was found to be less important. The uncertainties arising from climate variability and the differences between climate change scenarios do not strongly affect the range of global cropland futures. Some overlap occurred across all of the conditional probabilistic futures, except for those based on SSP3. We conclude from this that completely different worlds, albeit sharing low to medium population development, can result in very similar cropland futures at the aggregated global scale.
Muographic data analysis method for medium-sized rock overburden inspections
Authors: Tanaka Hiroyuki K. M. , Ohshiro Michinori
Published: March 2016

Abstract. Muographic measurements of rock overburdens are of particular interests because they can be applied to natural resources and undiscovered cave explorations, and even to searching for hidden chambers in historic architectural structures. In order to derive the absolute density distribution of the overburden, we conventionally needed to know the accurate information about the measurement conditions, e.g., the detector's geometrical acceptance, detection efficiency, measurement time, etc. in order to derive the absolute value of the transmitted muon flux. However, in many cases, it is not a simple task to accurately gauge such conditions. Open-sky muon data taken with the same detector are useful as reference data to cancel these factors, however, if the detector is not transportable, this data taking method is not feasible. In this work, we found that the transmitted muon flux will follow a linear function of the areal density along the muon path as long as the incident muon energies are below a few hundred GeV. Based on this finding, we proposed a simple analysis method that does not require detailed knowledge of the detector's conditions by combining the independently measured density information for the partial volume of the target. We anticipate that this simple method is applicable to future muographic measurements of rock overburdens.
Community Intercomparison Suite (CIS) v1.3.2: A tool for intercomparing models and observations
Authors: Watson-Parris Duncan , Schutgens Nick , Cook Nicholas , Kipling Zak , Kershaw Philip , Gryspeerdt Edward , Lawrence Bryan , Stier Philip
Published: March 2016

Abstract. The Community Intercomparison Suite (CIS) is an easy-to-use command-line tool which has been developed to allow the straightforward intercomparison of remote sensing, in-situ and model data. While there are a number of tools available for working with climate model data, the large diversity of sources (and formats) of remote sensing and in-situ measurements necessitated a novel software solution. Developed by a professional software company, CIS supports a large number of gridded and ungridded data sources "out-of-the-box", including climate model output in NetCDF or the UK Met Office pp file format, CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization), MODIS (MODerate resolution Imaging Spectroradiometer), Cloud and Aerosol CCI (Climate Change Initiative) level 2 satellite data, and a number of in-situ aircraft and ground station datasets. The open-source architecture also supports user defined "plugins" to allow many other sources to be easily added. Many of the key operations required when comparing heterogenous datasets are provided by CIS, including subsetting, aggregating, collocating and plotting the data. Output data is written to CF-compliant NetCDF files to ensure interoperability with other tools and systems. The latest documentation, including a user manual and installation instructions can be found on our website (http://cistools.net). Here we describe the need which this tool fulfils, followed by descriptions of its main functionality (as at version 1.3.2) and plugin architecture which make it unique in the field.
Influence of climate variability on water partitioning and effective energy and mass transfer in a semi-arid critical zone
Authors: Zapata-Rios Xavier , Brooks Paul D. , Troch Peter A. , McIntosh Jennifer , Rasmussen Craig
Published: March 2016

Abstract. The critical zone (CZ) is the heterogeneous, near-surface layer of the planet that regulates life-sustaining resources. Previous research has demonstrated that a quantification of the influxes of effective energy and mass transfer (EEMT) to the CZ can predict its structure and function. In this study, we quantify how climate variability in the last 3 decades (1984–2012) has affected water availability and the temporal trends in EEMT. This study takes place in the 1200 km2 upper Jemez River basin in northern New Mexico. The analysis of climate, water availability, and EEMT was based on records from two high-elevation SNOTEL stations, PRISM data, catchment-scale discharge, and satellite-derived net primary productivity (MODIS). Results from this study indicated a decreasing trend in water availability, a reduction in forest productivity (4 g C m−2 per 10 mm of reduction in precipitation), and decreasing EEMT (1.2–1.3 MJ m2 decade−1). Although we do not know the timescales of CZ change, these results suggest an upward migration of CZ/ecosystem structure on the order of 100 m decade−1, and that decadal-scale differences in EEMT are similar to the differences between convergent/hydrologically subsidized and planar/divergent landscapes, which have been shown to be very different in vegetation and CZ structure.
Multiscale evaluation of the Standardized Precipitation Index as a groundwater drought indicator
Authors: Kumar Rohini , Musuuza Jude L. , Van Loon Anne F. , Teuling Adriaan J. , Barthel Roland , Ten Broek Jurriaan , Mai Juliane , Samaniego Luis , Attinger Sabine
Published: March 2016

Abstract. The lack of comprehensive groundwater observations at regional and global scales has promoted the use of alternative proxies and indices to quantify and predict groundwater droughts. Among them, the Standardized Precipitation Index (SPI) is commonly used to characterize droughts in different compartments of the hydro-meteorological system. In this study, we explore the suitability of the SPI to characterize local- and regional-scale groundwater droughts using observations at more than 2000 groundwater wells in geologically different areas in Germany and the Netherlands. A multiscale evaluation of the SPI is performed using the station data and their corresponding 0.5° gridded estimates to analyze the local and regional behavior of groundwater droughts, respectively. The standardized anomalies in the groundwater heads (SGI) were correlated against SPIs obtained using different accumulation periods. The accumulation periods to achieve maximum correlation exhibited high spatial variability (ranges 3–36 months) at both scales, leading to the conclusion that an a priori selection of the accumulation period (for computing the SPI) would result in inadequate characterization of groundwater droughts. The application of the uniform accumulation periods over the entire domain significantly reduced the correlation between the SPI and SGI (≈ 21–66 %), indicating the limited applicability of the SPI as a proxy for groundwater droughts even at long accumulation times. Furthermore, the low scores of the hit rate (0.3–0.6) and a high false alarm ratio (0.4–0.7) at the majority of the wells and grid cells demonstrated the low reliability of groundwater drought predictions using the SPI. The findings of this study highlight the pitfalls of using the SPI as a groundwater drought indicator at both local and regional scales, and stress the need for more groundwater observations and accounting for regional hydrogeological characteristics in groundwater drought monitoring.
A particle based model for soil water dynamics: how to match and step beyond Richards' equation?
Authors: Zehe E. , Jackisch C.
Published: March 2016

Abstract. Within this study we propose a stochastic approach to simulate soil water dynamics in the unsaturated zone by using a non-linear, space domain random walk of water particles. Soil water is represented by particles of constant mass, which travel according to the Itô form of the Fokker Planck equation. The model concept builds on established soil physics by estimating the drift velocity and the diffusion term based on the soil water characteristics. A naive random walk, which assumes all water particles to move at the same drift velocity and diffusivity, overestimated depletion of soil moisture gradients compared to a Richards' solver. This is because soil water and hence the corresponding water particles in smaller pore size fractions, are, due to the non-linear decrease of soil hydraulic conductivity with decreasing soil moisture, much less mobile. After accounting for this subscale variability of particle mobility, the particle model and a Richards' solver performed similarly during simulated wetting and drying circles in three distinctly different soils. The particle model typically produced slightly smaller top soil water contents during wetting and was faster in depleting soil moisture gradients during subsequent drainage phases. Within a real world benchmark the particle model matched observed soil moisture response to a moderated rainfall event even slightly better than the Richards' solver. The proposed approach is hence a promising, easy to implement alternative to the Richards equation. This is particularly also because it allows one to step beyond the assumption of local equilibrium during rainfall driven conditions. This is demonstrated by treating infiltrating event water particles as different type of particle which travel initially, mainly gravity driven, in the largest pore fraction at maximum velocity, and yet experience a slow diffusive mixing with the pre-event water particles within a characteristic mixing time.