bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase unwrapping issue in DInSAR measurements in the aspect of surface displacements on the mining areas
Authors: Kopeć Anna , Głąbicki Dariusz , Milczarek Wojciech , Bugajska Natalia , Owczarz Karolina
Published: March 2020

InSAR become more and more popular technique for monitoring mining excavation influence on terrain surface. Nowadays, research on the accuracy of InSAR measurements focuses on impact of external factors on SAR signal and process of phase unwrapping. SAR interferogram include information about a displacement in wrapped form – modulo 2π. Demodulation of phase (phase unwrapping) enable to restore true phase values and then correct interpretation of acquired information. Poor quality of data (low coherency) and large surface deformations cause phase discontinuities that make unwrapping process difficult and may generate incorrect results. Underground mining excavation, especially shallow or inducing seismic activity, may lead to large and abrupt surface displacements. Majority of unwrapping algorithms assume that the difference between any two adjacent samples in the continuous phase signal should not exceed a value of π. However, this assumption may be incorrect for large and abrupt surface displacements and lead to errors in the phase unwrapping and then to determination of incorrect values of surface displacements. Studies were conducted for areas where both natural and mining-induced seismic shocks occurred. DInSAR technique was used to create interferograms. Phase unwrapping processes were performed using Statistical-Cost, Network-Flow Algorithm for Phase Unwrapping (SNAPHU) for conventional parameters, modified discontinuity parameters and taking into account theoretical shock models (Mogi model). Research allowed to determine the impact of abrupt, large displacements on the phase unwrapping process.
A chemostratigraphic framework for the type-Maastrichtian
Authors: Vellekoop Johan , Kaskes Pim , Matthias Sinnesael , Jagt John W. M. , Speijer Robert P. , Claeys Philippe
Published: March 2020

The youngest time interval of the Cretaceous Period is known as the Maastrichtian, a reference to the marine strata exposed in the area surrounding the city of Maastricht, in the Netherlands-Belgium border region. The stratigraphic succession at the original type-locality of the Maastrichtian (ENCI quarry, NL) only covers the upper part of the Maastrichtian Stage as it is nowadays defined. However, in combination with similar rock sequences in several other quarries (e.g. Hallembaye, Curfs) in the region, a substantial part of the Maastrichtian Stage is represented.

While the type-Maastrichtian strata have provided a wealth of paleontological data, comparatively little geochemical work has been carried out on this succession. So far, the age assessment of, and stratigraphic correlation with, the type-Maastrichtian has been largely based on biostratigraphy and preliminary attempts at cyclostratigraphy, techniques that are hampered by bioprovincialism and the presence of stratigraphic gaps in the succession. In recent years, stable carbon isotope stratigraphy has been proven to be a powerful tool for correlating Upper Cretaceous strata on a global scale. When calibrated with biostratigraphic events, carbon isotope stratigraphy can be used to test the synchroneity of bio-events and reconcile inter-regional biostratigraphic schemes. Therefore, we have generated the first high-resolution stable carbon isotope stratigraphy for the type-Maastrichtian, using the extensive sample set acquired in the context of the Maastrichtian Geoheritage Project. In combination with elemental data generated using µXRF (e.g. Ca, Si, Al, Ti, Fe wt%), our record presents the first high-resolution chemostratigraphy for the type-Maastrichtian. This new chemostratigraphic framework enables us to refine the age-model for studied strata, and allows a better regional and global correlation with the type-Maastrichtian successions, placing the paleontological records from the type-Maastrichtian in a global context.  
Main morpho-structural changes and eruptions of Etna in 2016-2019 captured by satellite observations
Authors: Marchese Francesco , Neri Marco , Behncke Boris , Genzano Nicola
Published: March 2020

Persistently active volcanoes such as Etna, in southern Italy, are subject to frequent morphological and structural changes, especially at the summit. In recent decades, in particular, Etna has shown an evident increase in both summit and flank eruptive activity. This caused a striking transformation of the morphologies of its summit craters, which increased in number and size, also causing the formation of new small eruptive vents, fumarolic fields, fractures and crater collapses. Sometimes these morpho-structural modifications of the top of the volcano have been so rapid that they have not been all recorded accurately, or they have occurred in sequences so rapid as to overlap the effects of the eruptions, making some transitional events between an eruption and the next one. Eruptive activity during the period considered occurred mostly at the summit craters of Etna (May 2016: Voragine; February-April 2017: New Southeast Crater and fissures on its slopes; August and November-December 2018: New Southeast Crater). This was interrupted by the brief fissure eruption on the upper southeast flank of the volcano on 24-27 December 2018; renewed eruptions occurred at the New Southeast Crater and fissures on its flanks in May-July 2019. Finally, in September 2019, eruptive activity shifted to the Northeast Crater and Voragine, the latter feeding intermittent lava flows into the adjacent Bocca Nuova crater. In cases like this, satellite observations can complete terrestrial monitoring systems, providing a useful contribution of knowledge and detail of the eruptive activity and morpho-structural transformations of greater significance. In this study, we analysed the Mt. Etna activity using data from the Multispectral Instrument (MSI) and the Operational Land Imager (OLI), respectively onboard Sentinel-2 and Landsat 8 satellites, processed by means of the recently proposed NHI (Normalized Hotspot Indices) algorithm. The latter allowed us to identify thermal anomalies associated to main effusive and explosive activities as well as to the smaller eruptive events, revealing in some cases thermal phenomena several days in advance that can be interpreted as potential precursors. In addition, NHI also showed a fair sensitivity in grasping the incipient fracturing of the Etna summit area, an important phenomenon in the life of this volcano due to its close correlation with the slow lateral collapses that characterize its flanks, and which in turn can trigger lateral eruptions that are potentially dangerous for the Etnean populations.
Deglacial sea ice variability at the continental margin off western Dronning Maud Land
Authors: Müller Juliane , Gebhardt Catalina , Mollenhauer Gesine , Tiedemann Ralf
Published: March 2020

Reconstructions of sea ice conditions proximal to the Antarctic coast are often hampered by a limited preservation potential of diatoms in these areas. While silica frustules are affected by opal dissolution, specific organic molecules, highly branched isoprenoids (HBIs) produced by diatoms, are well preserved in continental margin and shelf sediments and may help to overcome this gap. Here, we present biomarker and geochemical data obtained from a very well 14C-dated gravity core from the continental slope off Atka Bay in the northeastern part of the Weddell Sea. HBIs, the HBI-based PIPSO25 index (Vorrath et al., 2019), glycerol dialkyl glycerol tetraether (GDGT) proxies and phytosterols reveal highly variable sea ice conditions and water temperatures as well as primary productivity changes over the last deglacial. These biomarker records are compared to ice core data and further complemented by physical property and XRF scanning data to estimate potential linkages between oceanic forcing and ice-shelf dynamics.

 

References

Vorrath, M.E., Müller, J., Esper, O., Mollenhauer, G., Haas, C., Schefuß, E., and Fahl, K., 2019. Highly branched isoprenoids for Southern Ocean sea ice reconstructions: a pilot study from the Western Antarctic Peninsula. Biogeosciences, v. 16, no. 15, p. 2961-2981.
Correlation of core and downhole seismic velocities in high-pressure metamorphic rocks: A case study for the COSC-1 borehole, Sweden
Authors: Kästner Felix , Pierdominici Simona , Elger Judith , Berndt Christian , Zappone Alba , Kück Jochem , Schleicher Anja Maria
Published: March 2020

Deeply rooted thrust zones are key features of tectonic processes and the evolution of mountain belts. Exhumed and deeply-eroded orogens like the Scandinavian Caledonides allow to study such systems from the surface. Previous seismic investigations of the Seve Nappe Complex have shown indications for a strong but discontinuous reflectivity of this thrust zone, which is only poorly understood. The correlation of seismic properties measured on borehole cores with surface seismic data can help to constrain the origin of this reflectivity. In this study, we compare seismic velocities measured on cores to in situ velocities measured in the borehole. The core and downhole velocities deviate by up to 2 km/s. However, velocities of mafic rocks are generally in close agreement. Seismic anisotropy increases from about 5 to 26 % at depth, indicating a transition from gneissic to schistose foliation. Differences in the core and downhole velocities are most likely the result of microcracks due to depressurization of the cores. Thus, seismic velocity can help to identify mafic rocks on different scales whereas the velocity signature of other lithologies is obscured in core-derived velocities. Metamorphic foliation on the other hand has a clear expression in seismic anisotropy. To further constrain the effects of mineral composition, microstructure and deformation on the measured seismic anisotropy, we conducted additional microscopic investigations on selected core samples. These analyses using electron-based microscopy and X-ray powder diffractometry indicate that the anisotropy is strongest for mica schists followed by amphibole-rich units. This also emphasizes that seismic velocity and anisotropy are of complementary importance to better distinguish the present lithological units. Our results will aid in the evaluation of core-derived seismic properties of high-grade metamorphic rocks at the COSC-1 borehole and elsewhere.
Using Eddy-Covariance to understand CO2 and CH4 flux dynamics within a temperate, coastal wetland on French Island, Victoria, Australia
Authors: Peck Matthew , Reef Ruth , Tapper Nigel , Daly Edoardo , Burgess Leigh , Guyot Adrien
Published: March 2020

Coastal wetlands play a pivotal role in regulating both carbon (CO2) and methane (CH4) concentrations across the globe. The amount of CO2 and CH4 stored and released by these ecosystems is becoming more understood, in particular, within each aspect of the ecosystem. However, how the dynamics of the ecosystem affect CO2 and CH4 fluxes on a microclimate level is poorly understood, as well as the overall flux of these Greenhouse Gases (GHGs) within temperate, coastal wetlands. Current research primarily focuses on inland wetlands and coastal wetlands in sub-tropical and tropical regions. Thus, this research aims to investigate CO2 and CH4 fluxes within coastal, temperate wetlands, and improve the understanding of how environmental dynamics impact the flux of these critically important Greenhouse Gases (GHGs).

 

To satisfy this aim, the use of the Eddy-Covariance (EC) method was employed. An EC station was installed on the South-West tip of French Island, Victoria, Australia in late February 2018. The collected data demonstrates the challenges with collecting micro-climate data in an ecosystem with ever-changing environmental conditions. The preliminary results indicate how sensitive flux dynamics are within coastal, temperate wetlands, in particular, to factors such as: tidal and seasonal inundation, seasonal vegetation dynamics, and shifting ecological gradients. The data obtained by the EC station provides a preliminary indication of the complexities of accounting for, and understanding, carbon and methane movement through coastal wetlands in general. The full dataset will aid in improving this understanding, specifically for rare, temperate wetland environments, increasing the knowledge base on how flux dynamics of carbon and methane are affected when collected via open-source methods in dynamic environments.
IEA Wind Task 36 Forecasting
Authors: Giebel Gregor , Shaw Will , Frank Helmut , Pinson Pierre , Draxl Caroline , Zack John , Möhrlen Corinna , Kariniotakis Georges , Bessa Ricardo
Published: March 2020

Wind power forecasts have been used operatively for over 20 years. Despite this fact, there are still several possibilities to improve the forecasts, both from the weather prediction side and from the usage of the forecasts. The International Energy Agency (IEA) Wind Task on Wind Power Forecasting organises international collaboration, among national weather centres with an interest and/or large projects on wind forecast improvements (NOAA, DWD, UK MetOffice, ...), forecast vendors and forecast users.
Collaboration is open to IEA Wind member states, 12 countries are already therein.

The Task is divided in three work packages: Firstly, a collaboration on the improvement of the scientific basis for the wind predictions themselves. This includes numerical weather prediction model physics, but also widely distributed information on accessible datasets. Secondly, we will be aiming at an international pre-standard (an IEA Recommended Practice) on benchmarking and comparing wind power forecasts, including probabilistic forecasts. This WP will also organise benchmarks for NWP models. Thirdly, we will be engaging end users aiming at dissemination of the best practice in the usage of wind power predictions.

The main result is the IEA Recommended Practice for Selecting Renewable Power Forecasting Solutions. This document in three parts (Forecast solution selection process, and Designing and executing forecasting benchmarks and trials, and their Evaluation) takes its outset from the recurrent problem at forecast user companies of how to choose a forecast vendor. The first report describes how to tackle the general situation, while the second report specifically describes how to set up a forecasting trial so that the result is what the client intended. Many of the pitfalls which we have seen over the years, are avoided.

Other results include a paper on possible uses of uncertainty forecasts, an assessment of the uncertainty chain within the forecasts, and meteorological data on an information portal for wind power forecasting. This meteorological data is used for a benchmark exercise, to be announced at the conference. The poster will present the latest developments from the Task, and announce the next activities.
Soil available resource C:N ratio regulates the priming effect by maintaining microbial C:N stoichiometric balance in long-term fertilized paddy soils
Authors: Ge Tida , Zhu Zhenke , Wu Jinshui
Published: March 2020

Fertilization practices can influence the soil nutrients and fertility status, which subsequently induce changes in soil carbon (C):nitrogen (N) ratio and rebuilt C:N stoichiometric balances between microbial biomass and resources. In this study, we investigated how available resource C:N ratio can regulate the priming effect (PE) to maintain microbial C:N stoichiometric balance by adding 13C-labeled glucose to four long-term fertilized paddy soils [Control (no fertilization), NPK (fertilized with mineral NPK fertilizers) , NPKS (NPK combined with straw), NPKM (NPK combined with manure)]. Glucose addition significantly increased SOC mineralization and subsequently induced a positive priming effect at day 2 of incubation, whereas the PE became negative after 20 days. DOC contents were increased by more than 1000% with glucose addition at day 2, whereas they rapidly decreased to -10% to -50% compared with those in soils without glucose addition. With the changes in available and biomass C and N, the microbial C:N imbalance initially increased to 3.3–6.8, and then reduced to the level as that in the soils without glucose addition. At the end of incubation, the microbial C:N imbalance in the glucose-treated soils was ranked as Control < NPK < NPKM < NPKS. This suggested that, without organic fertilization, soils were highly susceptible to labile C and increased SOC mineralization, leading to C limitation. The PE was positively related to DOC and NH4+ ratio, but negatively associated with microbial C:N imbalance, suggesting that the labile C supplied stimulated microbial stoichiometric decomposition of SOM. Glucose addition modified enzyme activities after 20 days, to allow the microorganisms to break up complex C compounds for C source. Our findings suggested that soil microorganisms could regulate extracellular hydrolytic enzyme production and their relative stoichiometric ratios to obtain necessary elements, thereby adjusting the microbial biomass C:N to the resource stoichiometry.
Evaluation and applicability of the spatio-temporal complementarity of the solar and wind resources for the optimized design of renewable energy scenarios
Authors: Jerez Sonia , Mellado-Cano Javier , Lorente-Plazas Raquel , Jiménez-Guerrero Pedro , García-Valero Juan Andrés , Montávez Juan Pedro
Published: March 2020

We present and test a parsimonious model to help designing optimized wind and photovoltaic fleets, e.g. guaranteeing that the renewable production closely follows the electricity demand curve or any other optimization criteria. First, time-series of weather variables, from high-resolution gridded datasets, are transformed into time-series of wind and PV power potential production, which can be seen as capacity factor (CF) estimates. Second, a combination of hierarchical and non-hierarchical clustering is performed to identify regions with similar temporal variability of the CF series. Third, a linear combination of the resulting mean regional CF series is constructed to be fitted, for instance, to get the best production-demand adjustment, or under alternative optimization criteria such as minimum cost of installations that guarantee a certain supply. The coefficients obtained for each CF series after the fitting or optimization exercise, to which the condition of being zero or positive must be imposed and which, optionally, could be individually forced to vary within a certain range, will indicate the optimum amount of installed power capacity needed in the each region under the chosen optimization criteria. Illustrating the method, it has been applied over Europe at the monthly time-scale using the ERA5 reanalysis, but its applicability in other spatial and temporal scales is immediate. The results support its utility to design optimized renewable energy scenarios.

ACKNOWLEDGMENTS: This work is supported by the projects CLIMAX (20642/JLI/18) funded by the Fundación Séneca – Agencia de Ciencia y Tecnología de la Región de Murcia, and EASE (RTI2018-100870-A-I00) funded by the Spanish Ministry of Science, Innovation and Universities.
Development and characterization of a high precision QCLAS for selective NO2 measurement
Authors: Sobanski Nicolas , Schwarzenbach Beat , Tuzson Béla , Emmenegger Lukas , Worton Dave R. , Farren Naomi , Mace Tatiana , Sutour Christophe
Published: March 2020

   Nitrogen dioxide (NO2) is an atmospheric pollutant whose emissions are mostly linked to anthropogenic activities. It is, with nitric oxide (NO), the most abundant member of the nitrogen oxides family in tropospheric urban air (mixing ratios up to hundreds of ppbv), with a lifetime ranging from hours to days. NO2 is well known for its role as a boundary layer ozone and organic nitrates precursor and for affecting the oxidation capacity of the atmosphere. It has thus been subject to emissions mitigation policies and ambient air amount fraction monitoring for a few decades. The latter fully relies on the Chemiluminescence Detection technique (CLD), which is an indirect method measuring NO2 after conversion to NO.
   Recent advances in spectroscopy led to the development of direct and more selective ways to measure NO2. The currently running European Metrology for Nitrogen Dioxide (MetNO2) project, involving more than 15 European academic and industrial partners, promises to fill the gap in reliable and complete datasets for laboratory and field testing of those measurement techniques.
Here we present the results of a performance investigation of a high precision Quantum Cascade Laser Absorption Spectrometer (QCLAS) for the selective measurement of NO2 performed in the frame of the MetNO2 project. This instrument is based on a mid-IR QCL emitting at 6 μm and a custom-made, low noise astigmatic Herriott type multipass cell with an effective optical path length of 100 m to measure NO2 concentration in the low pptv range. We focus on determining precision, long-term stability and potential biases related to sampling conditions such as ambient pressure, temperature and humidity. The QCLAS device is then compared to other direct spectroscopic (CAPS, CRDS, IBBCEAS) and indirect (CLD) techniques. We also report on the results of a three weeks side-by-side field comparison at an urban air monitoring station of the Swiss National Air Pollution Monitoring Network (NABEL), involving the newly developed QCLAS, and commercial CAPS and CLD instruments.
   We show that the QCLAS is well suited for monitoring of NO2 concentration in ambient air and its performances in term of precision and stability surpass those of the CLD device and compete well with other direct measurement techniques.
To burn or not to burn? Impact of in-situ oil burning by-products on marine plankton: A mesocosm experimental approach
Authors: Magiopoulos Iordanis , Chantzaras Christos , Symiakaki Katerina , Antoniou Eleftheria , Pavloudi Christina , Romano Filomena , Piperakis Giorgos , Zanaroli Giulio , Kalogerakis Nikolaos , Pitta Paraskevi
Published: March 2020

In-situ oil burning (isOB) is one of the oil-spill mitigation measures and has been used after some major oil-spill events such as the Deepwater Horizon oil spill in the Gulf of Mexico. Although the ecological impact of oil spills and mitigation measures on the marine ecosystem are of great interest, the toxicity and biodegradation potential of isOB by-products have been poorly addressed and mainly are an unknown.

We investigated the effects of burned oil residue and soot deposition on the marine plankton communities of the oligotrophic Eastern Mediterranean Sea using a mesocosm experimental approach. Coastal water (collected at 300 m from the coast, north of Crete, Greece) was incubated in 3.5 m3 mesocosms for 26 days. Three different treatments in triplicates were tested. In one treatment, 2 L of Iranian Crude Oil were added and burned (Burned treatment) while soot was collected and deposited in the form of artificial rain in more mesocosms (Soot treatment) using a custom-designed soot collection apparatus. The third treatment served as the non-contaminated control (Control treatment). Samples were collected at 9 time points (from Day 0 to Day 26) and the plankton, from viruses to micro-plankton, was studied using flow cytometry and inverted microscopy.  

Although the abundance of prokaryotes was slightly decreased in Burned and Soot treatments compared to the Control, the percentage of active heterotrophic bacteria and their relative size (based on their cytometric characteristics) was higher, which is an indication of increased bacterial activity in the contaminated treatments. Viral to Prokaryote Ratio and pico/nano-eukaryotic abundance were significantly increased in the Burned treatment compared to the Control, which could explain the lower bacterial abundance, despite the estimated increased activity, in the Burned treatment. Also, ciliate abundance was significantly lower in the Burned treatment while the opposite was observed in the Soot treatment (up to three orders of magnitude difference between Burned and Soot) compared to Control. Moreover, soot deposits seem to have had a positive effect on the abundance of dinoflagellates and diatoms.

To our knowledge, this is the first experiment to study the effects of isOB on whole marine plankton communities. It is evident that the in-situ oil burning has a significant effect on the plankton communities not only at the event site but also on distant areas through the soot deposition.     
GLEAM evaporation and soil moisture: current state and ongoing efforts
Authors: Martin-Gonzalez Reyes , Martens Brecht , De Lannoy Gabrielle , Lievens Hans , R. Pagán Brianna , Rains Dominik , Zhong Feng , G. Miralles Diego
Published: March 2020

Approximately two-thirds of continental precipitation is evaporated back into the atmosphere. This highlights the influence of terrestrial evaporation for the distribution of hydrological resources, from catchment to planetary scales. The ability to monitor terrestrial evaporation dynamics is critical for climatological applications, since evaporation directly affects air temperature, influences air humidity and cloud formation, and is intrinsically connected to photosynthesis. To date, terrestrial evaporation cannot be observed directly from space, and in situ networks remain too sparse for both research and practical activities, making terrestrial evaporation one of the most uncertain components of Earth’s energy and water balance. However, a range of approaches have been proposed over the last decade to indirectly derive evaporation by applying models that combine the satellite-observed environmental and climatic drivers of the flux. One of these pioneering methods is the Global Land Evaporation Amsterdam Model (GLEAM; Miralles et al. 2011). 

GLEAM combines global satellite observations of meteorological variables – (e.g.) precipitation, surface net radiation and air temperature – and surface characteristics – (e.g.) soil and vegetation water content and snow depth. Since its publication almost 10 years ago, the model has been widely used to analyse trends in the water cycle, study land–atmospheric feedbacks or benchmark climate models. Advantages of GLEAM over analogous methods are the estimation of evaporation under cloud conditions due to the exploitation of microwave data, the explicit estimation of root-zone soil moisture data, and the detailed calculation of rainfall interception. Current model development efforts concentrate on (a) the increase in spatial resolution for its application to water management and agricultural applications and (b) the assimilation of novel satellite observations. This presentation provides a general overview of the framework and concentrates on ongoing efforts that strive in the direction of assimilating Gravity Recovery and Climate Experiment (GRACE) and Soil Moisture Active–Passive (SMAP) observations to improve the root-zone soil moisture estimates.

 

References  Miralles, D. G., Holmes, T. R. H., De Jeu, R. A. M., Gash, J. H., Meesters, A. G. C. A. and Dolman, A. J.: Global land-surface evaporation estimated from satellite-based observations, Hydrol. Earth Syst. Sci., 15(2), 453–469, doi:10.5194/hess-15-453-2011, 2011.
Evaporites reveal Pleistocene basin dynamics in the Danakil depression (northern Afar, Ethiopia)
Authors: Rime Valentin , Foubert Anneleen , Fentimen Robin , Negga Haileyesus , El Korh Afifé , Adatte Thierry , Hajdas Irka , Atnafu Balemwal , Kidane Tesfaye
Published: March 2020

The Danakil depression (Afar, Ethiopia) is a rift valley forming the southernmost part of the Red Sea rift. It is situated between the Ethiopian plateau and the Danakil block and is thought to represent an advanced stage of rifting, characterized by important tectonic and volcanic activity. Its floor is situated 120 meters below sea level and is covered by salt pans.

This study focuses on a 625 m deep borehole drilled in the central part of the basin. It mainly consists of evaporites dominated by halite along with clastic and carbonate sediments. Lithostratigraphy and facies description were completed by micropaleontological, geochemical, mineralogical and organic matter analysis. They reveal the complex history of this rift basin. Two marine Red Sea incursions are identified. Strong water stratification during the older marine incursion led to the formation of sapropel layers and magnesite. The restriction of the basin and the strong aridity led to the formation of evaporites, culminating in the deposition of potash salts. Between the two marine events, continental evaporites contributed to several hundreds of meters of basin fill.  The younger marine incursion was probably characterized by wetter environments, resulting in the deposition of smaller volumes of evaporites. Since then, hypersaline lakes and salt pans filled the basin. Ongoing radiocarbon and U/Th datings will constrain further the Pleistocene stratigraphy and timing of the marine incursions.

These findings shed a new light on the basin history. The successive flooding and desiccation events are a consequence of sea-level variations but also important tectonic activity. Rift margin uplift prevented flooding during the Holocene sea-level highstand and contributed to the restriction of the depression. Significant basin subsidence at very short time scales created accommodation space for the voluminous sediment infill. This implies very active rifting during the last 250 ka.
Effect of different carbon sources on Dibenzothiophene degradation and Rhamnolipids production by Burkholderia sp. C3
Authors: Cao Jia , Ni Jinren , Li Qing X.
Published: March 2020

Dibenzothiophene (DBT) is a sulfur-containing PAH typically used as a model chemical to study biodegradation of PAHs and bioremediation. The effects of using different carbon sources (sodium gluconate, glucose, sodium pyruvate, sodium acetate and glycerol) as a co-substrates were investigated during DBT biodegradation by Burkholderia sp. C3 with respect to (i) bacterial (Burkholderia sp. C3) growth, (ii) DBT biodegradation kinetics, (iii) secretion of the biosurfactant rhamnolipids (RLs) and (iv) RLs characterization. This is the first study showing a direct association between RLs biosynthesis and DBT biodegradation induced by different carbon sources in Burkholderia species. The results indicated that bacterial growth supported by gluconate, glucose, pyruvate and glycerol, and the maximal OD600 achieved in presence of gluconate and glycerol. Glycerol and pyruvate significantly enhanced DBT biodegradation after 7 days, while glucose inhibited DBT biodegradation. RL is a glycolipid biosurfactant extensively studied in Pseudomonas species and its potential in the bioremediation field. Glycerol can induce C3 produce at least four RLs by HPLC separation and MALDI-TOF/TOF identification. Glycerol stimulated a dual function in C3 as a RL producer and a DBT degrader. The increase of RL biosynthesis and secretion facilitated biodegradation of DBT in C3. Additionally, RLs reduced the surface tension of cultures with glycerol which increased the bioavailability of DBT for Burkholderia sp. C3 to utilize it. The direct utilization of crude glycerol for bacteria to degrade pollutants must be cost-effective and environmentally friendly.
Aerosol pH and regime transition of sulfate formation in aerosol water during winter haze events in northern China
Authors: Tao Wei , Su Hang , Zheng Guangjie , Wang Jiandong , Liu Lixia , Wei Chao , Li Meng , Zhang Qiang , Poschl Ulrich , Cheng Yafang
Published: March 2020

Understanding the formation mechanism of severe haze is crucial for the development of efficient pollution control strategy. Recently, multiphase reactions in aerosol water has been suggested as an important source of sulfate aerosol during severe haze (Zheng et al., 2015;Cheng et al., 2016). Though several oxidation mechanisms have been recognized, the dominant oxidation pathway is still under debate reflecting a missing consensus. Based on a model survey with Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), we have investigated the variability of aerosol pH and regimes of sulfate formation through multiphase oxidation during the haze episodes in January of 2013. Our results show a large spatial and temporal variability in the aerosol pH and sulfate formation regimes. Surface aerosol pH shows a clear diurnal variation with low pH during daytime and high pH during night-time for most cases. Aerosol pH tends to decrease with increasing altitude in the lower atmosphere. For the scenario best reproduces the observations in Beijing, NO2, TMI+O2, O3 and H2O2 pathways can all dominate the production of sulfate in specific areas of the Beijing-Tianjin-Hebei (BTH) region. With the increasing height, O3 pathway and gas phase oxidation by OH radicals become more important. Moreover, sensitivity tests also suggest that, emissions of crustal particles, NH3 and soluble iron/manganese have great impacts on aqueous phase chemistry, and should be better constrained in future studies.

References:

Zheng, G. J., Duan, F. K., Su, H., Ma, Y. L., Cheng, Y., Zheng, B., Zhang, Q., Huang, T., Kimoto, T., Chang, D., Poschl, U., Cheng, Y. F., and He, K. B.: Exploring the severe winter haze in Beijing: the impact of synoptic weather, regional transport and heterogeneous reactions, Atmos. Chem. Phys., 15, 2969-2983, 10.5194/acp-15-2969-2015, 2015.

Cheng, Y. F., Zheng, G. J., Wei, C., Mu, Q., Zheng, B., Wang, Z. B., Gao, M., Zhang, Q., He, K. B., Carmichael, G., Poschl, U., and Su, H.: Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China, Sci Adv, 2, e1601530, UNSP e1601530,10.1126/sciadv.1601530, 2016.
An operational sociohydrological model to understand the feedbacks between community sensitivity and environmental flows for an endorheic lake basin, Lake Bakhtegan Iran
Authors: Amirkhani Masoud , Zarei Heidar , Radmanesh Fereydoun , Pande Saket
Published: March 2020

Climate change, drought, overuse of water from surface(-ground) water resources has caused major problems in endorheic basins across the world. One such basin is Bakhtegan Lake Basin, southwest of Iran. The water entering Bakhtegan Lake has decreased, which has led to a decrease in the water level of this lake. Secondly, groundwater level has decreased in the Bakhtegan aquifer. These problems occurred in the Bakhtegan basin as a result of neglecting human roles as theactive agency within the hydrology of the region. In this study, we present a sociohydrological model in order to simulate dynamic relationship between community sensitivity, which responds to environmental well-being, and water use state variables as key to understanding the competition between water allocation between agriculture and the environment in the basin. Furthermore, agriculture in this basin plays a key role in the economic livelihoods which in turns plays a major role in the competition of water allocation between agriculture and environment in the Bakhtegan area.

The sociohydrological model is developed by coupling water demand and balance based WEAP (Water Evaluation And Planning) model with community sensitivity dynamic equations of the sociohydrological model by Roobavannan et al. (2017). The unique aspect of this model is that the six parameters of the community sensitivity related equations are calibrated, while being coupled to WEAP, using Elitist Non-Dominated Sorting Genetic (NSGAII) Algorithm on observed annual streamflow at three gauges within the basin.

The results demonstrate that the calibrated coupled model is able to simulate past allocations of water to agriculture and the environment in the basin, which we compare with available records. Further, we provide non-dominated pareto set of parameters, that demonstrate equifinality in pareto superior parameters of community sensitivity.

References:

Roobavannan, M., Kandasamy, J., Pande, S., Vigneswaran, S., & Sivapalan, M. (2017). Role of sectoral transformation in the evolution of water management norms in agricultural catchments: A sociohydrologic modeling analysis. Water Resources Research, 53, 8344–8365. https://doi.org/10.1002/2017WR020671
Multi-Scale Numerical Model for Groundwater flow Simulation of a Karst Tunnel in Kunming,China
Authors: Xu Mo , Qi Jihong , Tang Yige , Li Xiao , Guo JIan
Published: March 2020

Due to the inhomogeneity of the carbonate rocks and discreteness of the karst water, delineation of the groundwater flow within karst area remains a challenging task as yet. Based on KunCheng tunnel of a water diversion project in KunMing, multi-scale groundwater flow models were set upto simulate the groundwater flow. Large scale model was used to obtain the boundary conditions and hydrogeological parameters, which were then assigned to the small scale model.The small scale model was generalized as an equivalent continuous medium, and two karst pipelines are established  by module River. After then,  the multi-scale numerical modelswere used to simulate the  groundwater seepage field and predict the recovery of groundwater after tunnel construction. The main results and conclusions are as follows.

(1)Black karst pipeline and white karst pipeline systems share one recharge source but have two independent discharge systems. The recharge source is the exposed karst rock in the northeast part of study area. Obstructed by aluminum clay rock of P1d, groundwater discharge is divided into two parts during the runoff process.

(2)During the tunnel construction process, the water level at the exit of White karst pipeline reduced 9m in pipe model B1 while reduced 10m in the solution fissure model B2, both two models suggest that the tunnel construction will cause the drainage of White karst pipeline exit. The water level at the exit of black karst pipeline reduced 1m in pipe model B1 while reduced 4m in the solution fissure model B2.

(3)In model B1, total water discharge during tunnel construction is 69876m3/d, in model B2 , the total water discharge is 95817 m3/d  and  is much larger than model B1 due to the quick groundwater transporting and exchange in karst pipeline..

(4)After the tunnel construction, exits of two pipelines and observation well see the water level recovery because of the formation sealing . The recovery trend is relatively rapid in the early stage, and slow in the later stage. It takes 8.5 years and 10 years for the exits of black and white pipelines and observation wells to reach the original water level, respectively. During the recovery process, groundwater exchange form was changing from pipe supplying aquifer to aquifer supplying pipe, which made model B2 recovered faster than model B1 in early stage, and vice versa.

Using large scale model combining with secondary scale model, and the module River to generalize karst pipeline can reflect the flow dynamic characteristics of karst pipeline effectively.
The role of air-sea ice-ocean interaction processes for Arctic-midlatitude linkages
Authors: Khosravi Sara , Rinke Annette , Dorn Wolfgang , Lüpkes Christof , Gryanik Vladimir , Chechin Dmitry , Jaiser Ralf , Handorf Dörthe
Published: March 2020

Climate models have deficits in reproducing Arctic circulation and sea ice development. The air-sea ice-ocean interaction parametrizations could be a potential reason of this shortcoming. In most climate models air-sea ice-ocean interaction are parametrized based on mid-latitude conditions which is not appropriate for polar region. The POLEX project, funded by Helmholtz Association and Russian Science Foundation, is studying the impact of improved representation of Arctic air-sea ice-ocean interaction on changes in Arctic atmospheric circulation and Arctic-midlatitude linkages. We have used a new suite of parametrizations, which are easily applicable for climate simulations and have been developed based on SHEBA expedition data by Gryanik and Lüpkes (2018). We implemented the new parametrizations in the global atmospheric model (ECHAM6) in the framework of POLEX to estimate its effect on regional Arctic and large-scale circulation changes. Several steps have been defined for implementing the new parameterization to be able to distinguish and understand better the impact of its parameters. Roughness length and stability functions for stable stratification have been modified. Here the initial results of ECHAM6 sensitivity runs for different steps of the parameterization will be presented. We will present first results from process-oriented evaluation over the Arctic sea ice, e.g. how is the impact on the simulation of the two states of the Arctic boundary layer in winter. Furthermore, we will show that the large-scale circulation reacts to the new parametrization in different months and years differently.
Reference:
Gryanik, V.M. and C. Lüpkes (2018) An efficient non-iterative bulk parametrization of surface fluxes for stable atmospheric conditions over polar sea-ice, Boundary-Layer Meteorol., 166, 301-325
Contribution of IASI to the observation of the dust aerosol diurnal cycle over Sahara
Authors: capelle virginie , chedin alain , Scott Noelle , Todd Martin
Published: March 2020

The Infrared Atmospheric Sounder Interferometer (IASI) is well suited for monitoring of dust aerosols because of its capability to determine both AOD and altitude of the dust layer, and because of the good match between the IASI times of observation (9.30 am and pm, local time) and the time of occurrence of the main Saharan dust uplift mechanisms. Here, starting from IASI-derived dust characteristics for an 11-year period, we assess the capability of IASI to bring realistic information on the dust diurnal cycle. We first show the morning and nighttime climatology of IASI-derived dust AOD for two major dust source regions of the Sahara: The Bodele Depression and the Adrar region. Compared with simulations from a high resolution model, permitting deep convection to be explicitly resolved, IASI performs well. In a second step, a Dust Emission Index specific to IASI is constructed, combining simultaneous information on dust AOD and mean altitude, with the aim of observing the main dust emission areas, daytime and nighttime. Comparisons are then made with other equivalent existing results derived from ground based or other satellite observations. Results demonstrate the capability of IASI to improve the documentation of dust distribution over Sahara over a long period of time. Associating observations of dust aerosols in the visible, on which a majority of aerosol studies are so far based, and in the infrared thus appears as a way to complement the results from other satellite instruments in view of improving our knowledge of their impact on climate.
Planform deviations in river channel alignment due to active landsliding in the High Himalaya of Bhutan
Authors: de Palézieux Larissa , Leith Kerry , Loew Simon
Published: March 2020

Large rock slope instabilities affect river channels both due to catastrophic failures and long-term creep. The relationship between rock slop instabilities and processes in the adjacent river system are typically assessed in terms of channel profile perturbations and cross-sectional morphology, e.g. excess topography. However, such relationships can also be evident in planform changes of the channel alignment, e.g. in landslide dams and long-term channel migration. Large scale creeping rock slope instabilities can be considered point sources which introduce sediment laterally to a river channel. In cases in which sediment production from one side of the channel exceeds that of the opposing side, the course of the river can be shifted towards the less active hillslope. The deviation of the channel from its original course may therefore be used as a proxy for relative sediment input of the two opposing hillslopes.

In order to characterize the planform morphology of the river channels, we treat them as signals fluctuating around a smoothed channel and use a fast Fourier transform to extract characteristic wavelengths and amplitudes of the stream network. We observe a consistent increase in amplitude of planform deviation with increasing wavelength with a variability of two orders of magnitude at the shortest wavelength (101 m) and less than one order of magnitude at longer wavelengths (103 m).

When comparing characteristic channel morphologies based on these analyses to the deviation of channels adjacent to mapped landslides, the amplitude of the deviation appears higher than those naturally occurring in the river system at wavelengths similar to twice the landslide width.
Impact of the models structure uncertainty in flood simulations: Simbach case study
Authors: Lin Qing , Leandro Jorge , Disse Markus , Sturm Daniel
Published: March 2020

The quantification of model structure uncertainty on hydraulic models is very important for flash flood simulations. The choice of an appropriate model structure complexity and assessment of the impacts due to infrastructure failure can have a huge impact on the simulation results. To assess the risk of flash floods, coupled hydraulic models, including 1D-sewer drainage and 2D-surface run-off models are required for urban areas because they include the bidirectional water exchange, which occurs between sewer and overland flow in a city [1]. By including various model components, we create different model structures. For example, modelling the inflow to the city with the 2D surface-runoff or with the delineated 1D model; including the sewer system or use a surrogate as an alternative; modifying the connectivity of manholes and pumps; or representing the drainage system failures during flood events. As the coupling pattern becomes complex, quantifying the model structure uncertainty is essential for the model structure evaluation. If one model component leads to higher model uncertainty, it is reasonable to conclude that the new component has a large impact in our model and therefore needs to be accounted for; if one component has a less impact in the overall uncertainty, then the model structure can be simplified, by removing that model component.

In this study, we set up seven different model structures [2] for the German city of Simbach. By comparison with two inflow calculation types (1D-delineated inflow or 2D-catchment), the existence of drainage system and infrastructure failures, the Model Uncertainty Factor (MUF) is calculated to quantify the model structure uncertainties and further trade-off values with Parameter Uncertainty Factor (PUF) [3]. Finally, we can obtain a more efficient hydraulic model with the essential model structure for urban flash flood simulation.

 

1. Leandro, J., Chen, A. S., Djordjevic, S., and Dragan, S. (2009). "A comparison of 1D/1D and 1D/2D coupled hydraulic models for urban flood simulation." Journal of Hydraulic Engineering-ASCE, 6(1):495-504.
2. Leandro, J., Schumann, A., and Pfister, A. (2016). A step towards considering the spatial heterogeneity of urban, key features in urban hydrology flood modelling. J. Hydrol., Elsevier, 535 (4), 356-365.
3. Van Zelm, R., Huijbregts, M.A.J. (2013). Quantifying the trade-off between parameter and model structure uncertainty in life cycle impact assessment, Environ. Sci. Technol., 47(16), pp. 9274-9280.

 