bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomarkers of oxidative stress and antioxidant defense in patients with type 1 diabetes mellitus
Authors: Alghazeer Rabia , Alghazir Nadia , Awayn Nuri , Ahtiwesh Obiyda , Elgahmasi Sana
Published: December 2018

Background: Oxidative stress has become the focus of interest in most biomedical disciplines and many types of clinical research. Increasing evidence from research on several diseases shows that oxidative stress is associated with the pathogenesis of diabetes and many other diseases. Objectives: We aimed to investigate the status of oxidative stress and antioxidant enzymes related parameters in type 1 diabetes mellitus (T1DM) patients. Patients and Methods: A total of 110 patients (70 patients newly diagnosed diabetic and 40 healthy) were studied by evaluating the level of lipid peroxidation (malondialdehyde [MDA]), nitric oxide (NO), fasting blood sugar (FBS), and glycated hemoglobin (HbA1c). Antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), were also evaluated. Results: The FBS and HbA1c levels were significantly higher in diabetic patients compared to those of healthy participants. Higher levels of MDA and NO were observed in the diabetic group compared to those in the healthy participants. A significant decrease was observed in serum SOD, CAT, and GPx activities in the serum of T1DM patients by 16.7%, 72.8%, and 15.3%, respectively (P < 0.05), as compared with their activities in the controls. On the basis of sex, both male and female patients showed a significant reduction in antioxidant levels as compared to their respective controls. Conclusions: These results indicated that oxidative status and antioxidant levels were affected in T1DM. The results suggested that the biomarkers such as the plasma levels of lipid peroxidation and antioxidants in early diagnosed diabetics can be used to monitor the developing complications of the diabetes.
Inter-grader agreement in the diabetic retinopathy screening program in Palestine
Authors: Banayot Riyad
Published: December 2018

Aims: This audit aims to assess the quality and accuracy of primary graders in the diabetic retinopathy screening program in the occupied Palestinian territories. Subjects and Methods: A retrospective audit of 198 image sets from eight fully trained primary graders in the diabetic retinopathy screening program in the occupied Palestinian territories was performed. An expert grader regraded all images and audited their quality. The interobserver agreement between primary graders and the expert grader and the corresponding Kappa coefficient were determined for overall grading, referable, nonreferable disease, and ungradable disease. The audit standard was set at 80% for interobserver agreement with a Kappa coefficient of 0.7. Results: The interobserver agreement was 80% or better for overall outcome, referable, and nonreferable disease. The Kappa coefficient was 0.70 (substantial) for the overall grading results, 0.72 (substantial) for referable disease, 0.86 (almost perfect) for nonreferable disease, and was 0.21 (fair) for ungradable disease. About 82% of pictures showed two positions, and 75% of pictures showed good and adequate quality. Conclusions: The audit demonstrates an adequate level of quality and accuracy for primary grading in the diabetic retinopathy screening program in the occupied Palestinian territories.
A stratified homotopy hypothesis
Authors: Ayala David , Francis John , Rozenblyum Nick
Published: December 2018

We show that conically smooth stratified spaces embed fully faithfully into

\infty

-categories. This articulates a stratified generalization of the homotopy hypothesis proposed by Grothendieck. Hence, each

\infty

-category defines a stack on conically smooth stratified spaces, and we identify the descent conditions it satisfies. These include

\mathbb R^1

-invariance and descent for open covers and blow-ups, analogous to sheaves for the h-topology in

\mathbb A^1

-homotopy theory. In this way, we identify

\infty

-categories as striation sheaves, which are those sheaves on conically smooth stratified spaces satisfying the indicated descent. We use this identification to construct by hand two remarkable examples of

\infty

-categories:

\mathcal B\mathsf{un}

, an

\infty

-category classifying constructible bundles; and

\mathcal E\mathsf {xit}

, the absolute exit-path

\infty

-category. These constructions are deeply premised on stratified geometry, the key geometric input being a characterization of conically smooth stratified maps between cones and the existence of pullbacks for constructible bundles.
What is Rhythmanalysis?
Authors: Lyon Dawn
Published: December 2018

In recent years, there has been growing interest in Henri Lefebvre�s posthumously published volume, Rhythmanalysis. For Lefebvre and more recent scholars, rhythmanalysis is a research strategy which offers a means of thinking space and time together in the study of everyday life, and this remains its strength and appeal.

What is Rhythmanalysis? addresses the task of how to do rhythmanalysis. It discusses the history and development of rhythmanalysis from Lefebvre to the present day in a range of fields including cultural history and studies of place, work and nature. For Lefebvre, it is necessary to be �grasped by� a rhythm at a bodily level in order to grasp it. And yet we also need critical distance to fully understand it. Rhythmanalysis is therefore both corporeal and conceptual. This book considers how the body is directly deployed as a research tool in rhythmanalytical research as well as how audio-visual methods can get at rhythm beyond the capacity of the senses to perceive it. In particular, the book includes detailed discussion of research on different forms of mobility � from driving to dancing � and on the social life of markets � from finance to fish.

Dawn Lyon highlights the gains, limitations and lively potential of rhythmanalysis for spatially, temporally and sensually attuned practices of research. This engaging text will be of interest to students and researchers in sociology, criminology, socio-legal studies, geography, urban studies, architecture, anthropology, economics and cultural studies
Orbital Poetics
Authors: Leonard Philip
Published: December 2018

What do we mean when we talk of ‘world’ literature? What does a global, even a planetary view reveal to us about literature, culture and being?

In Orbital Poetics Philip Leonard explores conceptions of the world through the history of writing, theory and culture from an orbital perspective. Starting with literary and theoretical writing on satellites, orbit and terrestrial ground from the ancient world to the 21st century, the book casts a revealing new light on what it means to consider literature and culture on a global scale. Along the way, Leonard draws on a wide range of thinkers, writers and texts: from Dante and Goethe to contemporary electronic literature; Haruki Murakami and Tom McCarthy by way of philosophers and theorists including Agamben, Derrida and Heidegger; as well as astronaut photography and popular culture texts, such as novels by Buzz Aldrin and Tess Gerritsen and Alfonso Cuarón’s film Gravity.
Vertical characterization of highly oxygenated molecules (HOMs) below and above a boreal forest canopy
Authors: Zha Qiaozhi , Yan Chao , Junninen Heikki , Riva Matthieu , Sarnela Nina , Aalto Juho , Quéléver Lauriane , Schallhart Simon , Dada Lubna , Heikkinen Liine , Peräkylä Otso , Zou Jun , Rose Clémence , Wang Yonghong , Mammarella Ivan , Katul Gabriel , Vesala Timo , Worsnop Douglas R. , Kulmala Markku , Petäjä Tuukka , Bianchi Federico , Ehn Mikael
Published: December 2018

Abstract. While the role of highly oxygenated molecules (HOMs) in new particle
formation (NPF) and secondary organic aerosol (SOA) formation is not in
dispute, the interplay between HOM chemistry and atmospheric conditions
continues to draw significant research attention. During the Influence of
Biosphere-Atmosphere Interactions on the Reactive Nitrogen budget (IBAIRN)
campaign in September 2016, profile measurements of neutral HOMs below and
above the forest canopy were performed for the first time at the boreal
forest SMEAR II station. The HOM concentrations and composition distributions
below and above the canopy were similar during daytime, supporting a
well-mixed boundary layer approximation. However, much lower nighttime HOM
concentrations were frequently observed at ground level, which was likely due
to the formation of a shallow decoupled layer below the canopy. Near the
ground HOMs were influenced by the changes in the precursors and oxidants and
enhancement of the loss on surfaces in this layer, while the HOMs above the
canopy top were not significantly affected. Our findings clearly illustrate
that near-ground HOM measurements conducted under stably stratified
conditions at this site might only be representative of a small fraction of
the entire nocturnal boundary layer. This could, in turn, influence the
growth of newly formed particles and SOA formation below the canopy where the
large majority of measurements are typically conducted.
H2SO4–H2O–NH3 ternary ion-mediated nucleation (TIMN): kinetic-based model and comparison with CLOUD measurements
Authors: Yu Fangqun , Nadykto Alexey B. , Herb Jason , Luo Gan , Nazarenko Kirill M. , Uvarova Lyudmila A.
Published: December 2018

Abstract. New particle formation (NPF) is known to be an important source
of atmospheric particles that impacts air quality, hydrological cycle, and
climate. Although laboratory measurements indicate that ammonia enhances NPF,
the physicochemical processes underlying the observed effect of ammonia on
NPF are yet to be understood. Here we present a comprehensive
kinetically based H2SO4–H2O–NH3
ternary ion-mediated nucleation (TIMN) model that is based on the
thermodynamic data derived from both quantum-chemical calculations and
laboratory measurements. NH3 was found to reduce nucleation
barriers for neutral, positively charged, and negatively charged clusters
differently, due to large differences in the binding strength of
NH3, H2O, and H2SO4 to small clusters of
different charging states. The model reveals the general favor of nucleation
of negative ions, followed by nucleation on positive ions and neutral
nucleation, for which higher NH3 concentrations are needed, in
excellent agreement with Cosmics Leaving OUtdoor Droplets (CLOUD)
measurements. The TIMN model explicitly resolves dependences of nucleation
rates on all the key controlling parameters and captures the absolute
values of nucleation rates as well as the dependence of TIMN rates on
concentrations of NH3 and H2SO4, ionization
rates, temperature, and relative humidity observed in the well-controlled
CLOUD measurements well. The kinetic model offers physicochemical insights into
the ternary nucleation process and provides a physics-based approach to
calculate TIMN rates under a wide range of atmospheric conditions.
Calibration of a multi-physics ensemble for greenhouse gas atmospheric transport model uncertainty estimation
Authors: Díaz-Isaac Liza I. , Lauvaux Thomas , Bocquet Marc , Davis Kenneth J.
Published: December 2018

Abstract. Atmospheric inversions have been used to assess biosphere-atmosphere CO2 surface exchanges at various scales, but variability among inverse flux estimates remains significant, especially at continental scales. Atmospheric transport errors are one of the main contributors to this variability. To characterize transport errors and their spatio-temporal structures, we present an objective method to generate a calibrated ensemble adjusted with meteorological measurements collected across a region, here the US upper Midwest in midsummer. Using multiple model configurations of the Weather Research and Forecasting (WRF) model, we show that a reduced number of simulations (less than 10 members) reproduces the transport error characteristics of a 45-member ensemble while minimizing the size of the ensemble. The large ensemble of 45-members was constructed using different physics parameterization (i.e., land surface models (LSMs), planetary boundary layer (PBL) schemes, cumulus parameterizations and microphysics parameterizations) and meteorological initial/boundary conditions. All the different models were coupled to CO2 fluxes and lateral boundary conditions from CarbonTracker to simulate CO2 mole fractions. Meteorological variables critical to inverse flux estimates, PBL wind speed, PBL wind direction and PBL height, are used to calibrate our ensemble over the region. Two calibration techniques (i.e., simulated annealing and a genetic algorithm) are used for the selection of the optimal ensemble using the flatness of the rank histograms as the main criterion. We also choose model configurations that minimize the systematic errors (i.e. monthly biases) in the ensemble. We evaluate the impact of transport errors on atmospheric CO2 mole fraction to represent up to 40 % of the model-data mismatch (fraction of the total variance). We conclude that a carefully-chosen subset of the physics ensemble can represent the errors in the full ensemble, and that transport ensembles calibrated with relevant meteorological variables provide a promising path forward for improving the treatment of transport errors in atmospheric inverse flux estimates.
Isotopic Constraints on the Atmospheric Sources and Formation of
Nitrogenous Species in Biomass-Burning-Influenced Clouds
Authors: Chang Yunhua , Zhang Yanlin , Li Jiarong , Tian Chongguo , Song Linlin , Zhai Xiaoyao , Zhang Wenqi , Huang Tong , Lin Yu-Chi , Zhu Chao , Fang Yunting , Lehmann Moritz F. , Chen Jianmin
Published: December 2018

Abstract. The interpretation of tropospheric cloud formation rests on understanding the sources and processes affecting aerosol constituents of the atmosphere that are preserved in cloudwater. However, this challenge is difficult to be quantitatively addressed based on the sole use of bulk chemical properties. Nitrogenous aerosols, mainly ammonium (NH4+) and nitrate (NO3−), play an important role in tropospheric cloud formation. Here we collected cloudwater samples at the summit of Mt. Tai (1545 m above sea level) in Eastern China during a long-lasting biomass burning (BB) event, and measured for the first time the isotopic compositions (mean ± 1σ) of cloudwater nitrogen species (δ15N-NH4+ = −6.53 ± 4.96 ‰, δ15N-NO3− = −2.35 ± 2.00 ‰, δ18O-NO3− = 57.80 ± 4.23 ‰), allowing insights into their sources and potential transformation mechanism within the clouds. Large contributions of BB to the cloudwater NH4+ (32.9 ± 4.6 %) and NO3− (28.2 ± 2.7 %) inventories were confirmed through a Bayesian isotopic mixing model, coupled with our newly-developed computational quantum chemistry module. Despite an overall reduction in total anthropogenic NOx emission due to effective emission control actions and stricter emission standards for vehicles, the observed cloud δ15N-NO3− values suggest that NOx emissions from transportation may have exceeded emissions from coal combustion. δ18O-NO3− values imply that the reaction of OH with NO2 is the dominant pathway of NO3− formation (57 ± 11 %), yet the contribution of heterogeneous hydrolysis of dinitrogen pentoxide was almost as important (43 ± 11 %).
Spatial distribution and temporal trend of ozone pollution in
China observed with the OMI satellite instrument, 2005–2017
Authors: Shen Lu , Jacob Daniel J. , Liu Xiong , Huang Guanyu , Li Ke , Liao Hong
Published: December 2018

Abstract. We use data from the new China Ministry of Ecology and Environment (MEE) network to show that OMI satellite observations of tropospheric ozone can successfully map the distribution of surface ozone pollution in China and the frequency of high-ozone episodes. After subtracting the Pacific background, OMI ozone enhancements over China can quantify mean summer afternoon surface ozone with a precision of 10.7 ppb and a spatial correlation coefficient R=0.73. Day-to-day correlations between OMI and the MEE ozone data are statistically significant but limited by noise in the individual OMI retrievals. OMI shows significantly higher values on surface ozone episode days (>82 ppb). An extreme value model can successfully predict the probability of surface ozone episodes from the daily OMI data. The 2005–2017 OMI record shows a 0.67 ppb a−1 increase in mean summer afternoon ozone in eastern China and an increasing frequency of ozone pollution episodes particularly in the north.
Atomic oxygen number densities in the MLT region measured by
solid electrolyte sensors on WADIS-2
Authors: Eberhart Martin , Löhle Stefan , Strelnikov Boris , Hedin Jonas , Khaplanov Mikhail , Fasoulas Stefanos , Gumbel Jörg , Lübken Franz-Josef , Rapp Markus
Published: December 2018

Abstract. Absolute profiles of atomic oxygen number densities with high vertical resolution have been determined in the MLT region from in-situ measurements by several rocket-borne solid electrolyte sensors. The amperometric sensors were operated in both controlled and uncontrolled modes and with various orientations on the fore and aft deck of the payload. Calibration was based on mass spectrometry in a molecular beam containing atomic oxygen produced in a microwave discharge. The sensor signal is proportional to the number flux onto the electrodes and the mass flow rate in the molecular beam was measured additionally to derive this quantity from the spectrometer reading. Numerical simulations provided aerodynamic correction factors to derive the atmospheric number density of atomic oxygen from the sensor data. The flight results indicate a preferable orientation of the electrode surface perpendicular to the rocket axis. While unstable during the upleg, the density profiles measured by these sensors show an excellent agreement with the atmospheric models and photometer results during the downleg of the trajectory. The high spatial resolution of the measurements allows the identification of small-scaled variations in the atomic oxygen concentration.
Evolution of 231Pa and 230Th in overflow waters of the North Atlantic
Authors: Deng Feifei , Henderson Gideon M. , Castrillejo Maxi , Perez Fiz F. , Steinfeldt Reiner
Published: December 2018

Abstract. Many palaeoceanographic studies have sought to use the
231Pa∕230Th ratio as a proxy for deep ocean circulation
rates in the North Atlantic. As of yet, however, no study has fully assessed
the concentration of, or controls on, 230Th and 231Pa in
waters immediately following ventilation at the start of Atlantic meridional
overturning. To that end, full water-column 231Pa and
230Th concentrations were measured along the GEOVIDE section,
sampling a range of young North Atlantic deep waters. 230Th and
231Pa concentrations in the water column are lower than those
observed further south in the Atlantic, ranging between 0.06 and
12.01 µBq kg−1 and between 0.37 and 4.80 µBq kg−1,
respectively. Both 230Th and 231Pa profiles generally
increase with water depth from surface to deep water, followed by decrease
near the seafloor, with this feature most pronounced in the Labrador Sea (LA
Sea) and Irminger Sea (IR Sea). Assessing this dataset using extended optimum
multi-parameter (eOMP) analysis and CFC-based water mass age indicates that
the low values of 230Th and 231Pa in water near the
seafloor of the LA Sea and IR Sea are related to the young waters present in
those regions. The importance of water age is confirmed for 230Th
by a strong correlation between 230Th and water mass age (though
this relationship with age is less clear for 231Pa and the
231Pa∕230Th ratio). Scavenged 231Pa and
230Th were estimated and compared to their potential concentrations
in the water column due to ingrowth. This calculation indicates that more
230Th is scavenged (∼80 %) than 231Pa (∼40 %), consistent with the relatively higher particle reactivity of
230Th. Enhanced scavenging for both nuclides is demonstrated near
the seafloor in young overflow waters. Calculation of the meridional transport of
230Th and 231Pa with this new GEOVIDE dataset enables a
complete budget for 230Th and 231Pa for the North
Atlantic. Results suggest that net transport southward of 230Th and
231Pa across GEOVIDE is smaller than transport further south in the
Atlantic, and indicate that the flux to sediment in the North Atlantic is
equivalent to 96 % of the production of 230Th and 74 % of
the production for 231Pa. This result confirms a significantly
higher advective loss of 231Pa to the south relative to
230Th and supports the use of 231Pa∕230Th to
assess meridional transport at a basin scale.
Turbulence measurements suggest high rates of new production over the shelf edge in the northeastern North Sea during summer
Authors: Bendtsen Jørgen , Richardson Katherine
Published: December 2018

Abstract. New production, i.e. that driven by allochthonous nutrient inputs, is the
only form of primary production that can lead to net increases in organic
material and is, therefore, important for understanding energy flow in marine
ecosystems. The spatial distribution of new production is generally, however,
not well known. Using data collected in July 2016, we analyse the potential
for vertical mixing to support new production in the upper layers of the
northeastern portion of the North Sea. Relatively large (up to >0.5 mmol N m−2 d−1) nitrate fluxes due to turbulent vertical
mixing into the euphotic zone were found at some stations over the shelf
edge, while low values (< 0.1 mmol N m−2 d−1) were found in
the deeper open area north of the shelf edge. The low vertical mixing rates
(dissipation rates of turbulent kinetic energy below 10−8 W kg−1,
corresponding to vertical turbulent diffusion coefficients of
10−6–10−5 m2 s−1) implied f
ratios of <0.02 in the open waters
north of the shelf edge. In the shallow (<50 m) southern and central part
of the study area, inorganic nutrients were low and nitrate undetectable,
suggesting negligible new production here, despite relatively high
concentrations of chlorophyll a being found in the bottom layer. Thus, high
rates of new production seem to be concentrated around the shelf-edge zone
and in association with localized features exhibiting enhanced vertical
mixing. We find that the nutricline depth is significantly deeper at the
shelf edge and interference with increased mixing in this deeper depth range
can explain the increased diapycnal nitrate fluxes. Overall, this suggests
that the shelf-edge zone may be the major nutrient supplier to the euphotic
zone in this area during the period of summer stratification.
Identifying teleconnections and multidecadal variability of East Asian
surface temperature during the last millennium in CMIP5 simulations
Authors: Ratna Satyaban B. , Osborn Timothy J. , Joshi Manoj , Yang Bao , Wang Jianglin
Published: December 2018

Abstract. We examine the relationships in models and reconstructions between the multidecadal variability of surface temperature in East Asia and two extratropical modes of variability: the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal oscillation (PDO). We analyze the spatial, temporal and spectral characteristics of the climate modes in Last Millennium, Historical and pre-industrial control simulations of three CMIP5/PMIP3 GCMs, to assess the relative influences of external forcing and unforced variability. These models produce PDO and AMO variability with realistic spatial patterns and their spectral characteristics. AMO internal variability strongly influences East Asia temperature in one model (bcc-csm1-1), but has a weak influence in the other two (CCSM4 and MPI-ESM-P). In all three models, external forcing greatly strengthens these statistical associations and hence the apparent teleconnection with the AMO. PDO internal variability strongly influences East Asian temperature in two of the three models, but external forcing makes this apparent teleconnection much weaker. This indicates that the AMO-East Asian temperature relationship is partly driven by external forcing whereas the PDO-temperature relationship is largely driven by internal variability. External forcing confounds attempts to diagnose the teleconnections of internal multidecadal variability. Using AMO and PDO indices that represent internal variability more closely and minimising the influence of external forcing on East Asia temperature can partly ameliorate this confounding effect. Nevertheless, these approaches still yield differences between the forced and control simulations and they cannot always be applied to paleoclimate reconstructions, so we recommend caution when interpreting internal variability teleconnections diagnosed from reconstructions that contain both forced and internal variations.
Contiguous United States wildland fire emission estimates during 2003–2015
Authors: Urbanski Shawn P. , Reeves Matt C. , Corley Rachel E. , Silverstein Robin P. , Hao Wei Min
Published: December 2018

Abstract. Wildfires are a major source of air pollutants in the United States. Wildfire
smoke can trigger severe pollution episodes with substantial impacts on
public health. In addition to acute episodes, wildfires can have a marginal
effect on air quality at significant distances from the source, presenting
significant challenges to air regulators' efforts to meet National Ambient
Air Quality Standards. Improved emission estimates are needed to quantify the
contribution of wildfires to air pollution and thereby inform decision-making
activities related to the control and regulation of anthropogenic air
pollution sources. To address the need of air regulators and land managers for improved wildfire
emission estimates, we developed the Missoula Fire Lab Emission Inventory
(MFLEI), a retrospective, daily wildfire emission inventory for the
contiguous United States (CONUS). MFLEI was produced using multiple datasets
of fire activity and burned area, a newly developed wildland fuels map and an
updated emission factor database. Daily burned area is based on a combination
of Monitoring Trends in Burn Severity (MTBS) data, Moderate Resolution
Imaging Spectroradiometer (MODIS) burned area and active fire detection
products, incident fire perimeters, and a spatial wildfire occurrence
database. The fuel type classification map is a merger of a national forest
type map, produced by the USDA Forest Service (USFS) Forest Inventory and
Analysis (FIA) program and the Geospatial Technology and Applications Center
(GTAC), with a shrub and grassland vegetation map developed by the USFS
Missoula Forestry Sciences Laboratory. Forest fuel loading is from a fuel
classification developed from a large set (> 26 000 sites) of FIA surface
fuel measurements. Herbaceous fuel loading is estimated using site-specific
parameters with the Normalized Difference Vegetation Index from MODIS. Shrub
fuel loading is quantified by applying numerous allometric equations linking
stand structure and composition to biomass and fuels, with the structure and
composition data derived from geospatial data layers of the LANDFIRE project.
MFLEI provides estimates of CONUS daily wildfire burned area, fuel
consumption, and pollutant emissions at a 250 m × 250 m resolution
for 2003–2015. A spatially aggregated emission product
(10 km × 10 km, 1 day) with uncertainty estimates is included to
provide a representation of emission uncertainties at a spatial scale
pertinent to air quality modeling. MFLEI will be updated, with recent years,
as the MTBS burned area product becomes available. The data associated with
this article can be found at https://doi.org/10.2737/RDS-2017-0039 (Urbanski et al., 2017).
A high-frequency and high-resolution image time series of the Gornergletscher – Swiss Alps – derived from repeated UAV surveys
Authors: Benoit Lionel , Gourdon Aurelie , Vallat Raphaël , Irarrazaval Inigo , Gravey Mathieu , Lehmann Benjamin , Prasicek Günther , Gräff Dominik , Herman Frederic , Mariethoz Gregoire
Published: December 2018

Abstract. The rapid growth of drone technology provides an efficient means to monitor the response of alpine glaciers to climate warming. Here we report a new dataset based on images collected during ten intensive UAV surveys of the Gornergletscher glacial system (Switzerland) carried out approximately every two weeks throughout the summer 2017. The final products, available at: https://doi.org/10.5281/zenodo.1487862 (Benoit et al, 2018), consist in a series of 10 cm resolution ortho-images, Digital Elevation Models of the glacier surface, and Matching Maps that can be used to quantify ice surface displacements and velocities. Used on its own, this dataset allows mapping the glacier and monitoring surface velocities over the summer at a very high spatial resolution. Coupled with a classification or feature detection algorithm, it enables extracting structures such as surface drainage networks, debris or snow cover. The approach we present can be used in the future to gain insights into ice flow dynamics.
ESM-SnowMIP: assessing snow models and quantifying snow-related climate feedbacks
Authors: Krinner Gerhard , Derksen Chris , Essery Richard , Flanner Mark , Hagemann Stefan , Clark Martyn , Hall Alex , Rott Helmut , Brutel-Vuilmet Claire , Kim Hyungjun , Ménard Cécile B. , Mudryk Lawrence , Thackeray Chad , Wang Libo , Arduini Gabriele , Balsamo Gianpaolo , Bartlett Paul , Boike Julia , Boone Aaron , Chéruy Frédérique , Colin Jeanne , Cuntz Matthias , Dai Yongjiu , Decharme Bertrand , Derry Jeff , Ducharne Agnès , Dutra Emanuel , Fang Xing , Fierz Charles , Ghattas Josephine , Gusev Yeugeniy , Haverd Vanessa , Kontu Anna , Lafaysse Matthieu , Law Rachel , Lawrence Dave , Li Weiping , Marke Thomas , Marks Danny , Ménégoz Martin , Nasonova Olga , Nitta Tomoko , Niwano Masashi , Pomeroy John , Raleigh Mark S. , Schaedler Gerd , Semenov Vladimir , Smirnova Tanya G. , Stacke Tobias , Strasser Ulrich , Svenson Sean , Turkov Dmitry , Wang Tao , Wever Nander , Yuan Hua , Zhou Wenyan , Zhu Dan
Published: December 2018

Abstract. This paper describes ESM-SnowMIP, an international coordinated modelling
effort to evaluate current snow schemes, including snow schemes that are
included in Earth system models, in a wide variety of settings against local
and global observations. The project aims to identify crucial processes and
characteristics that need to be improved in snow models in the context of
local- and global-scale modelling. A further objective of ESM-SnowMIP is to
better quantify snow-related feedbacks in the Earth system. Although it is
not part of the sixth phase of the Coupled Model Intercomparison Project
(CMIP6), ESM-SnowMIP is tightly linked to the CMIP6-endorsed Land Surface,
Snow and Soil Moisture Model Intercomparison (LS3MIP).
Multi-model approach to quantify groundwater level prediction
uncertainty using an ensemble of global climate models and
multiple abstraction scenarios
Authors: Mustafa Syed M. Touhidul , Hasan M. Moudud , Saha Ajoy Kumar , Rannu Rahena Parvin , Van Uytven Els , Willems Patrick , Huysmans Marijke
Published: December 2018

Abstract. Worldwide, groundwater resources are under a constant threat of overexploitation and pollution due to anthropogenic and climatic pressures. For sustainable management and policy making a reliable prediction of groundwater levels for different future scenarios is necessary. Uncertainties are present in these groundwater level predictions and originate from greenhouse gas scenarios, climate models, conceptual hydro(geo)logical models (CHMs) and groundwater abstraction scenarios. The aim of this study is to quantify the individual uncertainty contributions using an ensemble of 2 greenhouse gas scenarios (representative concentration pathway 4.5 and 8.5), 22 global climate models, 15 alternative CHMs and 5 groundwater abstraction scenarios. This multi-model ensemble approach was applied to a drought prone study area in Bangladesh. Findings of this study, firstly, point at the strong dependence of the groundwater levels on the CHMs considered. All groundwater abstraction scenarios showed a significant decrease in groundwater levels. If the current groundwater abstraction trend continues, the groundwater level is predicted to decline about 5 to 6 times faster for the future period 2026–2047 compared to the baseline period (1985–2006). Even with a 30 % lower groundwater abstraction rate, the mean monthly groundwater level would decrease by up to 14 m in the southwestern part of the study area. The groundwater abstraction in the northwestern part of Bangladesh has to reduce by 60 % of the current abstraction to ensure sustainable use of groundwater. Finally, the difference in abstraction scenarios was identified as the dominant uncertainty source. CHM uncertainty contributed about 23 % of total uncertainty. The alternative CHM uncertainty contribution is higher than the recharge scenario uncertainty contribution, including the greenhouse gas scenario and climate model uncertainty contributions. It is recommended that future groundwater level prediction studies should use multi-model and multiple climate and abstraction scenarios.
Hydrogeochemical controls on brook trout spawning habitats in a coastal stream
Authors: Briggs Martin A. , Harvey Judson W. , Hurley Stephen T. , Rosenberry Donald O. , McCobb Timothy , Werkema Dale , Lane Jr. John W.
Published: December 2018

Abstract. Brook trout (Salvelinus fontinalis) spawn in fall and
overwintering egg development can benefit from stable, relatively warm
temperatures in groundwater-seepage zones. However, eggs are also sensitive
to dissolved oxygen concentration, which may be reduced in discharging
groundwater (i.e., seepage). We investigated a 2 km reach of the coastal
Quashnet River in Cape Cod, Massachusetts, USA, to relate preferred fish
spawning habitats to geology, geomorphology, and discharging groundwater
geochemistry. Thermal reconnaissance methods were used to locate zones of
rapid groundwater discharge, which were predominantly found along the central
channel of a wider stream valley section. Pore-water chemistry and temporal
vertical groundwater flux were measured at a subset of these zones during
field campaigns over several seasons. Seepage zones in open-valley
sub-reaches generally showed suboxic conditions and higher dissolved solutes
compared to the underlying glacial outwash aquifer. These discharge zones
were cross-referenced with preferred brook trout redds and evaluated during
10 years of observation, all of which were associated with discrete alcove
features in steep cutbanks, where stream meander bends intersect the glacial
valley walls. Seepage in these repeat spawning zones was generally stronger
and more variable than in open-valley sites, with higher dissolved oxygen and
reduced solute concentrations. The combined evidence indicates that regional
groundwater discharge along the broader valley bottom is predominantly
suboxic due to the influence of near-stream organic deposits; trout show no
obvious preference for these zones when spawning. However, the meander bends
that cut into sandy deposits near the valley walls generate strong oxic
seepage zones that are utilized routinely for redd construction and the
overwintering of trout eggs. Stable water isotopic data support the
conclusion that repeat spawning zones are located directly on preferential
discharges of more localized groundwater. In similar coastal systems with
extensive valley peat deposits, the specific use of groundwater-discharge points
by brook trout may be limited to morphologies such as cutbanks, where
groundwater flow paths do not encounter substantial buried organic material
and remain oxygen-rich.
Using paleoclimate reconstructions to analyse hydrological epochs associated with Pacific decadal variability
Authors: Zhang Lanying , Kuczera George , Kiem Anthony S. , Willgoose Garry
Published: December 2018

Abstract. The duration of dry or wet hydrological epochs (run lengths) associated with
positive or negative Inter-decadal Pacific Oscillation (IPO) or Pacific Decadal Oscillation (PDO) phases, termed Pacific decadal variability (PDV), is an
essential statistical property for understanding, assessing and managing
hydroclimatic risk. Numerous IPO and PDO paleoclimate reconstructions provide
a valuable opportunity to study the statistical signatures of PDV, including
run lengths. However, disparities exist between these reconstructions, making
it problematic to determine which reconstruction(s) to use to investigate
pre-instrumental PDV and run length. Variability and persistence on
centennial scales are also present in some millennium-long reconstructions,
making consistent run length extraction difficult. Thus, a robust method to
extract meaningful and consistent run lengths from multiple reconstructions
is required. In this study, a dynamic threshold framework to account for
centennial trends in PDV reconstructions is proposed. The dynamic threshold
framework is shown to extract meaningful run length information from multiple
reconstructions. Two hydrologically important aspects of the statistical
signatures associated with the PDV are explored: (i) whether persistence
(i.e. run lengths) during positive epochs is different to persistence during
negative epochs and (ii) whether the reconstructed run lengths have been
stationary during the past millennium. Results suggest that there is no
significant difference between run lengths in positive and negative phases of
PDV and that it is more likely than not that the PDV run length has been
non-stationary in the past millennium. This raises concerns about whether
variability seen in the instrumental record (the last ∼100 years), or
even in the shorter 300–400-year paleoclimate reconstructions, is
representative of the full range of variability.
Redressing the balance: quantifying net intercatchment groundwater flows
Authors: Bouaziz Laurène , Weerts Albrecht , Schellekens Jaap , Sprokkereef Eric , Stam Jasper , Savenije Hubert , Hrachowitz Markus
Published: December 2018

Abstract. Intercatchment groundwater flows (IGFs), defined as groundwater flows across topographic divides, can occur as regional groundwater flows that bypass headwater streams and only drain into the channel further downstream or directly to the sea. However, groundwater flows can also be diverted to adjacent river basins due to geological features (e.g., faults, dipping beds and highly permeable conduits). Even though intercatchment groundwater flows can be a significant part of the water balance, they are often not considered in hydrological studies. Yet, assuming this process to be negligible may introduce misrepresentation of the natural system in hydrological models, for example in regions with complex geological features. The presence of limestone formations in France and Belgium potentially further exacerbates the importance of intercatchment groundwater flows, and thus brings into question the validity of neglecting intercatchment groundwater flows in the Meuse basin. To isolate and quantify the potential relevance of net intercatchment groundwater flows in this study, we propose a three-step approach that relies on the comparison and analysis of (1) observed water balance data within the Budyko framework, (2) results from a suite of different conceptual hydrological models and (3) remote-sensing-based estimates of actual evaporation. The data of 58 catchments in the Meuse basin provide evidence of the likely presence of significant net intercatchment groundwater flows occurring mainly in small headwater catchments underlain by fractured aquifers. The data suggest that the relative importance of net intercatchment groundwater flows is reduced at the scale of the Meuse basin, as regional groundwater flows are mostly expected to be self-contained in large basins. The analysis further suggests that net intercatchment groundwater flow processes vary over the year and that at the scale of the headwaters, net intercatchment groundwater flows can make up a relatively large proportion of the water balance (on average 10 % of mean annual precipitation) and should be accounted for to prevent overestimating actual evaporation rates.
Automated snow avalanche release area delineation – validation of existing algorithms and proposition of a new object-based approach for large-scale hazard indication mapping
Authors: Bühler Yves , von Rickenbach Daniel , Stoffel Andreas , Margreth Stefan , Stoffel Lukas , Christen Marc
Published: December 2018

Abstract. Snow avalanche hazard is threatening people and infrastructure in all alpine
regions with seasonal or permanent snow cover around the globe. Coping with
this hazard is a big challenge and during the past centuries, different
strategies were developed. Today, in Switzerland, experienced avalanche
engineers produce hazard maps with a very high reliability based on avalanche
database information, terrain analysis, climatological data sets and
numerical modeling of the flow dynamics for selected avalanche tracks that
might affect settlements. However, for regions outside the considered
settlement areas such area-wide hazard maps are not available mainly because
of the too high cost, in Switzerland and in most mountain regions around the
world. Therefore, hazard indication maps, even though they are less reliable
and less detailed, are often the only spatial planning tool available. To
produce meaningful and cost-effective avalanche hazard indication maps over
large regions (regional to national scale), automated release area
delineation has to be combined with volume estimations and state-of-the-art
numerical avalanche simulations. In this paper we validate existing potential release area (PRA) delineation
algorithms, published in peer-reviewed journals, that are based on digital
terrain models and their derivatives such as slope angle, aspect, roughness
and curvature. For validation, we apply avalanche data from three
different ski resorts in the vicinity of Davos, Switzerland, where
experienced ski-patrol staff have mapped most avalanches in detail for many
years. After calculating the best fit input parameters for every tested
algorithm, we compare their performance based on the reference data sets.
Because all tested algorithms do not provide meaningful delineation between
individual PRAs, we propose a new algorithm based
on object-based image analysis (OBIA). In combination with an automatic
procedure to estimate the average release depth (d0), defining the avalanche
release volume, this algorithm enables the numerical simulation of thousands
of avalanches over large regions applying the well-established avalanche
dynamics model RAMMS. We demonstrate this for the region of Davos for two
hazard scenarios, frequent (10–30-year return period) and extreme (100–300-year
return period). This approach opens the door for large-scale avalanche
hazard indication mapping in all regions where high-quality and high-resolution
digital terrain models and snow data are available.
Indirect seismic economic loss assessment and recovery evaluation using nighttime light images – application for Wenchuan earthquake
Authors: Wang Jianfei , Zhang Jingfa , Gong Lixia , Li Qiang , Zhou Dan
Published: December 2018

Abstract. Indirect seismic economic loss not only impacts regional economic recovery
policies but is also related to economic assistance at the national level.
Due to cross-regional economic activities and the difficulty of obtaining
data, it is difficult for the indirect economic loss survey to cover all
economic activities. However, nighttime light in an area can reflect the
economic activity of the region. This article focuses on the indirect
economic losses caused by the 2008 Wenchuan earthquake and evaluation of the
progress of restoration and reconstruction based on nighttime light images.
First, the functional relationship between GDP and nighttime light
parameters is established based on pre-earthquake data. Next, the
indirect loss of the earthquake is evaluated by the nighttime light
attenuation in the disaster area after the earthquake. Then, the capacity
recovery, which is characterized by the brightness recovery process of the
light area, is evaluated. Lastly, the process of light expansion in the
disaster area is analyzed to evaluate the speed and efficiency of economic expansion.
The Pelagic In situ Observation System (PELAGIOS) to reveal biodiversity, behavior and ecology of elusive oceanic fauna
Authors: Hoving Henk-Jan , Christiansen Svenja , Fabrizius Eduard , Hauss Helena , Kiko Rainer , Linke Peter , Neitzel Philipp , Piatkowski Uwe , Körtzinger Arne
Published: December 2018

Abstract. There is a need for cost-efficient tools to explore deep ocean ecosystems to collect baseline biological observations on pelagic fauna (zooplankton and nekton) and establish the vertical ecological zonation in the deep sea. The Pelagic In situ Observation System (PELAGIOS) is a 3000 m-rated slowly (0.5 m/s) towed camera system with LED illumination, an integrated oceanographic sensor set (CTD-O2) and telemetry allowing for online data acquisition and video inspection (Low Definition). The High Definition video is stored on the camera and later annotated using the VARS annotation software and related to concomitantly recorded environmental data. The PELAGIOS is particularly suitable for open ocean observations of gelatinous fauna, which is notoriously undersampled by nets and/or destroyed by fixatives. In addition to counts, diversity and distribution data as a function of depth and environmental conditions (T, S, O2), in situ observations of behavior, orientation and species interactions are collected. Here we present an overview of the technical setup of the PELAGIOS as well as example observations and analyses from the eastern tropical North Atlantic. Comparisons to MOCNESS net sampling and data from the Underwater Vision Profiler are provided and discussed.
The Bortoluzzi Mud Volcano (Ionian Sea, Italy) and its potential for
tracking the seismic cycle of active faults
Authors: Cuffaro Marco , Billi Andrea , Bigi Sabina , Bosman Alessandro , Caruso Cinzia G. , Conti Alessia , Corbo Andrea , Costanza Antonio , D'Anna Giuseppe , Doglioni Carlo , Fertitta Gioacchino , Gasperini Luca , Italiano Francesco , Lazzaro Gianluca , Ligi Marco , Longo Manfredi , Martorelli Eleonora , Petracchini Lorenzo , Petricca Patrizio , Polonia Alina , Sgroi Tiziana
Published: December 2018

Abstract. The Ionian Sea in southern Italy is at the center of active interaction and convergence between the Eurasian and African-Adriatic plates in the Mediterranean. This area is seismically active with instrumentally/historically-recorded Mw > 7.0 earthquakes and it is affected by recently-discovered long strike-slip faults across the active Calabrian accretionary wedge. Many mud volcanoes occur on top of the wedge. A recently-discovered one (here named Bortoluzzi Mud Volcano, BMV) was surveyed during the Seismofaults 2017 cruise (May 2017). Bathymetric-backscatter surveys, seismic reflection profiles, geochemical and earthquake data as well as a gravity core are here used to geologically, geochemically, and geophysically characterize this structure. The BMV is a circular feature ≃22 m high and ≃1100 m in diameter with steep slopes (up to a dip of 22°). It sits atop the Calabrian accretionary wedge and a system of flower-like oblique-slip faults that are probably seismically active as demonstrated by earthquake hypocentral and focal data. Geochemistry of water samples from the seawater column on top of the BMV shows a significant contamination of the bottom waters from saline (evaporite-type) CH4-dominated crustal-derived fluids similar to the fluids collected from a mud volcano located in the Calabria main land over the same accretionary wedge. These results attest for the occurrence of an open crustal conduit through the BMV down to at least the Messinian evaporites at about −3000 m. This evidence is also substantiated by Helium isotope ratios and by different geochemical data from three sea water columns located elsewhere in the Ionian Sea. Conclusions are drawn on the origin of the BMV and on the potential of this type of structures for tracking the seismic cycle of active faults. Due to the widespread diffusion of mud volcanoes in seismically active settings, this study may contribute to indicate a potential and feasible future path for the use of these ubiquitous structures in favor of the mitigation of natural hazards.