bluuebunny/crossref_metadata_2025 huggingface dataset:
Waste water treatment as a source of microplastic pollution
Authors: Dixon Simon , Trusler Megan , Kiernan Charlotte
Published: March 2020

Plastic pollution has now been found across the Earth’s active zone, with recent studies finding plastics in remote parts of the Pacific Ocean, in deep ocean trenches, and in the high Arctic. Of particular concern are microplastics (<5mm diameter), these can be ingested by organisms where they have been shown to cause both chronic and acute health problems. In order to address plastic pollution there is a need to understand how plastic in the oceans is linked to terrestrial sources. Recent conceptual models have illustrated that plastic pollution is a complex interlinked problem with myriad sources and pathways introducing and redistributing plastic around the environment. Terrestrial and freshwater sources are likely to be significant contributors to overall plastic pollution; however, to date they remain poorly understood or quantified. There is a need to both identify and quantify sources of microplastic pollution in terrestrial and freshwater environments, as well as vectors which lead to the redistribution and storage of microplastics in hotspots of accumulation.

In this study we present pilot data attempting to characterise the influence of Waste Water Treatment (WWT) processes on environmental plastic pollution. Using the concept of the “Plastic Cycle” we identify various pathways for plastics present in domestic waste water to enter the environment after treatment. Using two study areas in the UK, we quantify the microplastic loading to the environment from WWT effluent, which is discharged to freshwaters, and from WWT sludge, which is spread on agricultural land as fertiliser. Our results show that both effluent and sludge are important sources of microplastics to the environment. However, these can be of the same order of magnitude as other sources indicating that addressing environmental microplastic pollution is likely to need an integrated approach. Our results also show these sources have lower loadings at some of our sites than reported in other studies, this indicates both treatment processes in WWT and management practices in sludge spreading are likely to be important in determining environmental loading of microplastics at specific sites. The influence of waste water treatment as a source of microplastic pollution needs to be further constrained, but our pilot data indicates a complex picture which needs to be better understood in order to inform environmental governance.
3d stereo reconstruction of train paths for supporting maintenance operations
Authors: Nitti Massimiliano , Mosca Nicola , Reno Vito , Cosimo Patruno , diSumma Maria , Colella Roberto , Stella Ettore
Published: March 2020

Railway infrastructure maintenance is a critical activity for ensuring safe train operations, due to the constant mechanical stress and wear and tear that crucial parts of the infrastructure such as rail and catenary undergo under use. Several methodologies and systems have been devised for diagnosing and prevent anomalies and minimize safety risks, that measure geometrical parameters and assess the way the infrastructure interacts with the train. While those techniques help at identifying anomalies when they occur, sometimes they are not able to provide enough evidence on the reasons behind the failure. A visual inspection can surely help in assessing the causes of failure, especially when they happen during train operations, without introducing any disruption to the service to schedule a specific check with a visit to the site. This work investigates the design of a stereo vision system that can be mounted on diagnostic trains so that a virtual visit to the site can be done when needed, by providing a 3d reconstruction of the surrounding of a train path. To achieve this, in the proposed system two color cameras can be mounted on the head or tail locomotive in a stereo configuration. They are triggered by an axle encoder mounted on the train at a fixed distance of 2 mt. This way the acquired point clouds can be registered together to achieve a full 3d reconstruction of the train path so that an offline, remote inspection of parts of the rails and catenaries can support in detecting, and possibly prevent, future anomalies. Moreover, since the reconstruction extends beyond train paths for a few meters, the 3d reconstruction of the railway can be exploited in different ways too, for example by preventing that foreign objects invade and jeopardize the train loading gauge.
The genesis of an ice sample matters!
Authors: Heger Dominik
Published: March 2020

We performed laboratory experiments to examine the relationship between the technique of preparing a frozen sample; its morphology; and chemical speciation. The luminescence of aromatic compounds (naphthalene, methylnaphthalene, anthracene) was utilized to learn about the extent of the compounds’ aggregation.

In aqueous solutions, the cooling rate determines the morphology of the resulting ice samples (analyzed with an environmental scanning microscope), (Vetráková, Neděla et al. 2019) the extent of the solute crystallization, and the plasticity of the freeze-concentrated solution (FCS) glass formed in the veins in between the ice crystals. Faster cooling allows higher degree of hydration of the aromatic compounds in the FCS. Conversely, vapor deposition of naphthalene on ice at 253 K results in microscopic naphthalene crystals, suggesting molecular mobility on the surface layer of ice at atmospherically relevant temperatures. (Ondrušková, Krausko et al. 2018) Surface acidity was proved via sulfonephthalein dyes, finding strong dependence on the salts present.(Imrichova, Vesely et al. 2019)

Our results connect the freezing methods and sample history with the compounds’ chemical identity in ice.

 

 

Imrichova, K., L. Vesely, T. M. Gasser, T. Loerting, V. Nedela and D. Heger (2019). "Vitrification and increase of basicity in between ice Ih crystals in rapidly frozen dilute NaCl aqueous solutions." J Chem Phys 151(1): 014503.

Ondrušková, G., J. Krausko, J. N. Stern, A. Hauptmann, T. Loerting and D. Heger (2018). "Distinct Speciation of Naphthalene Vapor Deposited on Ice Surfaces at 253 or 77 K: Formation of Submicrometer-Sized Crystals or an Amorphous Layer." The Journal of Physical Chemistry C 122(22): 11945-11953.

Vetráková, Ľ., V. Neděla, J. Runštuk and D. Heger (2019). "The morphology of ice and liquid brine in an environmental scanning electron microscope: a study of the freezing methods." The Cryosphere 13(9): 2385-2405.
The effect of the choice of time resolution on the prediction of deep drainage rates in rocky covers
Authors: Baumgartl Thomas , Shaygan Mandana
Published: March 2020

Numerical modelling is a tool allowing the prediction of water flow and water balance based on material properties and time dependent input information at defined boundaries. Long time series are often required for a well informed assessment of the performance of a site. It has been shown that covers as a preferred option constructed in semi-arid and arid climates on mine sites to manage water flows and to prevent deep drainage have a characteristic bi-modal pore system largely caused by a large fraction of coarse rocks. Bi-modal water retention curves have been established for such covers which have proven to describe the response to precipitation with higher accuracy. Meteorological data as input information are in many cases only available on a daily basis if time series over decades are used for modelling. For a bi-modal pore system with often very high values for saturated hydraulic conductivity, a daily time-step may be to large to capture numerically the response in water flow. The objective of the presented work is the comparison of modelled deep drainage data for a specific cover design where hourly data are compared with daily input data. The latter were aggregated from the hourly information.

The results from the numerical modelling showed that for environments with high intensity rainfall events the calculated amount of deep drainage was by up to 10% smaller for the aggregated daily input data compared to the hourly data.

The presentation will inform which rainfall events contributed primarily to the difference in the water balance parameters and to which extent a generalisation can be made on the choice or requirement to choose an appropriate time step for specific climatic conditions.
Vaccinium vitis-idaea decreases the dependence of alpine soil properties from soil moisture
Authors: Makarov Mikhail , Malysheva Tatiana , Kadulin Maksim , Sabirova Rida
Published: March 2020

Climatic and plant community changes are observed in the alpine belt of the Teberda Reserve (the Northwest Caucasus) in the last decades. Increase of average monthly temperature in the summer months in 2006-2018 was 1.8-2.2 ºC in comparison with 1966-1990. For the last 13 years, the maximum temperature in July and August reached 22.1-23.2 ºC vs. 20.5 ºC in 1966-1990, and minimum temperature during these months did not fall lower than -1.8 ºC whereas in 1966-1990 it fell up to -7.0 ºC. At the same time decrease of summer precipitation, especially in July and August is observed (average 80-100 mm per month vs. 150-160 mm in 1966-1990). Against this climatic background, a significant increase of dwarf shrub with ericoid mycorrhizal symbiosis (Vaccinium vitis-idaea) occurs in plant community of alpine lichen heath. As ericoid mycorrhiza is characterized by high enzymatic activity capable to transform and mobilize soil organic matter, we assume that the appearance of Vaccinium vitis-idaea in grass ecosystems can change soil properties. Simultaneously the observed tendency to decrease the amount of summer atmospheric precipitation in mountain regions can change soil moisture which is also highly important to control soil microbial activity and organic matter transformation.

The properties of the mountain-meadow soil of the alpine lichen heath, characterizing labile forms of carbon, nitrogen and phosphorus, as well as biological activity at different soil moisture and in the presence or absence of Vaccinium vitis-idaea in the plant community, have been studied. It has been shown that under V. vitis-idaea soil is characterized by greater acidity and less responsive to changes in soil moisture. Differences in properties in the presence and absence of V. vitis-idaea are predominantly determined by the expressed response of the soil to changes in moisture in the absence of dwarf shrub. Under herbal vegetation, when soil moisture decreases, concentrations of inorganic nitrogen, activity of N-mineralization and nitrification, microbial biomass and soil respiration decrease, but concentrations of labile organic carbon and nitrogen, and enzymatic activity increase. Such changes indicate a shift in organic matter transformation from mineralization to depolymerization, more characteristic of ectomycorrhizal and ericoid mycorrhizal dominated ecosystems. Thus, both factors (soil moisture and invasions of ericoid mycorrhizal plant species) should be taken into account in predicting changes of alpine ecosystems functioning.

This study was supported by Russian Science Foundation (16-14-10208).
Investigating land subsidence of transitional environments
Authors: Zoccarato Claudia , Parrella Eugenia
Published: March 2020

Lagoons and deltas are characterized by the presence of transitional environments, such as low-lying plains or islands, salt marshes, and tidal flats with fundamental value in terms of biodiversity, recreational activities, and protection of inland territories from storms. The fate of these morphological landforms is severely threatened by the ongoing rise of the mean sea level (SLR) and land subsidence (LS). The loss of elevation relative to mean sea level, i.e. SLR plus LS, must be counterbalanced by accretion of inorganic sediments and biodegradation of organic matter. A large contribution to LS of transitional landforms is due to auto-compaction of the Holocene sediments. In fact, the large porosity and compressibility of these recent deposits, especially when the organic fraction is high, are responsible for a significant thickness reduction because of consolidation when new deposition occurs on the surface. SAR interferometry on deep-founded and surface radar scatterers, ground-based monitoring equipment (deep levelling benchmarks, SET, accretion traps), and a novel in-situ loading test have been used in the Venice Lagoon to distinguish between deep and shallow LS contributions, i.e. LS occurring below and above the Pleistocene / Holocene bound. After a review of the available dataset, the present contribution describes the modelling activities that are ongoing to understand the collected measurements. In particular, an advance coupled mixed finite-element poromechanical model is used to reproduce the loading test carried out on the Lazzaretto Nuovo marshland on summer 2019. With the aim of reliably characterize the geomechanical properties of the Holocene sediments of the tidal-marsh, a number of plastic tanks were filled with seawater, reaching a cumulative load of 40 kN applied on a 2.5´1.8 m2 surface. Specific instrumentations were deployed before positioning the tanks to measure soil vertical displacement and pore overpressure at various depths below the load and distances from the load center. The numerical model uses linear piecewise polynomials and the lowest order Raviart–Thomas mixed space to represent the three-dimensional porous medium motion and the groundwater flow rate, respectively. The model is applied to the various loading and unloading phases that superpose to the tidal fluctuation of the lagoon level recorded over the 4-day test duration. The geomechanical properties thus derived constitute a significant advancement to understand the LS drivers in transitional environments and predict their resilience to SLR.    
Variability of ionospheric parameters by the Swarm satellites for different solar activity
Authors: Kotova Daria , Jin Yaqi , Miloch Wojciech
Published: March 2020

The use of satellite data allows us to study the variability of ionospheric plasma parameters globally without references to ground stations or receivers in different regions of the Earth. The Swarm mission, which was launched in 2014 and is still operational, allows us to investigate the effects of decreasing solar activity on the ionospheric variability. In our study we use the Swarm in-situ measurements of the electron density and derived parameters. This dataset provides characteristics of the plasma variability along the orbit and gives information on plasma density structures in the ionosphere in terms of their amplitudes, gradients and spatial scales. We analyze the variability of these parameters in the contexts of the northern and southern hemispheres, specific latitudinal regions, and the solar activity level. Understanding of the distribution of such parameters in the context of the solar activity level and selected ionospheric regions can have implications for the development of new satellite instruments and for the accuracy of GNSS precise positioning.
Provenance of the Saharan winter dust plume and its response to climatic variability over the last 200 kyr
Authors: Jewell Amy , Burton Will , Kunkelova Tereza , Crocker Anya , Röhl Ursula , Cooper Matthew , James Rachael , Xuan Chuang , Pike Alistair , Bakker Natalie , Bristow Charlie , Drake Nick , Wilson Paul
Published: March 2020

North Africa is very likely to warm over the coming century, but there is fundamental disagreement among climate model projections over the predicted response of rainfall to that warming. Geological records of wind-blown dust accumulating in marine sediment cores in the North Atlantic Ocean provide a way to assess the response of rainfall climate in the region to past intervals of global warmth.

 

Dust is transported to the North Atlantic Ocean from North Africa via two routes, a summer (northern) route and a winter (southern) route. Virtually everything we have learnt so far from marine sediment cores about North African hydroclimate has come from drill sites located beneath the summer (northern) dust plume. Here we report (i) geochemical records (radiogenic isotope (87Sr/86Sr and eNd) and XRF core scanning) from Ocean Drilling Project (ODP) Site 662 in the eastern equatorial Atlantic spanning the last 200,000 years and (ii) new 87Sr/86Sr and eNd data from North African dust sources. We redefine existing dust Preferential Source Areas (PSAs) into three geochemically distinct (Western, Central and Eastern) source regions. We show that ODP Site 662 is well-situated to study the palaeo-history of the previously under-studied African winter (southern) dust plume. We find that the primary source of terrigenous material to Site 662 throughout the past 200,000 years is palaeolake Megachad in the Central source region. This palaeolake basin is often described as the largest single dust source on Earth but comparatively little is known on geological timescales about its history. We show that its dust contribution to ODP Site 662 varies on orbital timescales, and that it reaches a minimum during insolation maxima, such as the last African Humid Period, coincident with lake high-stands. Large excursions in radiogenic isotope data reveal extreme variability in the relative strength of aeolian dust and distal riverine sources of terrigenous material, associated with hydroclimate change over the last 200 thousand years.
Green Sahara Megaperiods during the Pliocene: What was the role of North Atlantic Ocean temperature?
Authors: Wilson Paul , Jewell Amy , Crocker Anya , Buchanan Solana , Mitsunaga Bryce , Westerhold Thomas , Röhl Ursula , Russell James , Herbert Timothy
Published: March 2020

The Sahel region is one of the most vulnerable regions on Earth to anthropogenically-driven climate change, but also one of the least equipped to deal with the consequences. Predictions of precipitation levels over the forthcoming centuries diverge, not only in magnitude, but also in the sign of change. One key aspect of this uncertainty comes from the role of Atlantic Ocean sea surface temperatures (SST), which are known to exert a strong control over precipitation in the Sahel and are implicated in both the major drought of the late 20th century and extreme droughts associated with the Heinrich events of the last glacial. To better understand how Sahelian hydroclimate may respond to SST variability in a warmer world, we turn to the Pliocene epoch, when atmospheric CO2 levels were comparable to present.

 

We studied sediments from Ocean Drilling Project Site 659, which is situated in the subtropical North Atlantic beneath the major modern summer Saharan dust plume. Our new dust accumulation rates and X-ray fluorescence core scan data indicate that there were major shifts between highly arid conditions and humid intervals with vegetated or “Green Sahara” conditions over much of northern Africa, driven by both solar insolation and glacial-interglacial variability. We also report three unusually long Plio-Pliocene humid intervals (each lasting ca. 100 kyr) characterised by very low dust emissions, that we term “Green Sahara Megaperiods (GSMPs)”. All three of these GSMPs occur at times when insolation variability was weak, resulting in values close to the long-term mean. This observation strongly suggests that factors other than insolation drove the sustained humidity of GSMPs. We present paired alkenone SST estimates and multi-species planktonic foramaniferal isotope records from 3.5–2.3 Myr ago to explore the extent to which the GSMPs were accompanied by intervals of extended warmth in the surface waters of the North Atlantic Ocean.
On the Effectiveness of Land Management Decisions in Restoration of Hydrologic Ecosystem Services in Humid and Seasonal-Tropical Catchments
Authors: Ogden Fred L.
Published: March 2020

Cities in the humid- and seasonal-humid tropics depend on small watersheds for their water supplies.  Under normal conditions with ample rainfall, water supplies are reliable.   However, water shortages can occur during extended dry periods.  The literature contains contradictory findings regarding the effectiveness of different land management strategies aimed at enhanced delivery of hydrologic ecosystem services during periods of significant rainfall deficit, so-called “green infrastructure”.  Recent research results from field and modeling studies in the Panama Canal Watershed indicated that land-cover dependent flow paths play an important role in partitioning throughfall into subsurface stormflow and groundwater recharge.  Land management practices considered included continuous and rotational grazing, silvipastoral treatments, and different ages of secondary succession including old regrowth forest.  The effectiveness of land management was found to depend on both land use practice and annual rainfall as determined by orography in steep regions.   These dependencies at least partially explain some of the discrepancies in the literature.
Radiative heating of ice-covered waterbodies of varying morphologies
Authors: Ulloa Hugo N. , Winters Kraig B. , Wüest Alfred , Bouffard Damien
Published: March 2020

Millions of small, high-altitude lakes freeze their surface waters each winter season. Observations, however, reveal that their water temperature is increasing and the ice-on period is declining. Altering the thermal regime of ice-covered lakes have multiple impacts, including the loss of ecosystem services to increments in greenhouse gas emissions. These pervasive changes are affected by the heating rate of under-ice waters, which in turn regulates the water-to-ice heat flux, and therefore the rate of ice melting. In such aquatic systems, solar radiation warms the water beneath a diffusive boundary layer, thereby increasing its density and providing energy for convection in a diurnally-active mixing layer. Shallow regions are differentially heated to warmer temperatures, driving downslope buoyancy-driven currents that transport warm water to the interior basin. We characterize the energetics of these processes, focusing on the rate at which solar radiation supplies energy that is available to drive fluid motion. Using numerical simulations, we show that advective fluxes due to differential heating contribute to the evolution of the mixed-layer in waterbodies with significant shallow areas. We use a heat balance to assess the relative importance of differential heating to the one-dimensional effects of radiative heating and diffusive cooling at the ice-water interface in waterbodies of varying morphologies.
Fusion and mining of glacier surface flow velocity time series
Authors: Charrier Laurane , Yan Yajing , Koeniguer Elise , Trouvé Emmanuel , Millan Romain , Mouginot Jérémie , Derkacheva Anna
Published: March 2020

Glacier response to climate change results in natural hazards, sea level rise and changes in freshwater resources. To evaluate this response, glacier surface flow velocity constitutes a crucial parameter to study. Nowadays, more and more velocity maps at regional or global scales issued from satellite SAR and/or optical images tend to be available online or on-demand. Such amount of data requires appropriate data fusion strategies in order to generate displacement time series with improved precision and spatio-temporal coverage. The improved displacement time series can then be used by advanced multi-temporal analysis approaches for further physical interpretations of the phenomenon under observation. In this work, time series of Sentinel-2 (10~m resolution, every 5 days), Landsat-8 (15~m resolution, every 16 days) and Venus (5~m resolution, every 2 days) images acquired between January 2017 and September 2018, over the Fox glacier in the Southern Alps of New Zealand are investigated. Velocities are generated with an offset tracking technique using an automatic processing chain for every possible repeat cycles (2 days-100 days and 300 days to 400 days). Thousands of velocity maps are available, and they are subject to both uncertainty and data gaps. In order to produce a displacement time series as precise/complete as possible , we propose three fusion strategies: 1) use all the available Sentinel-2 displacement maps with different time spans. The goal is to construct a time series of displacement with respect to a common master by means of an inversion 2) take only Sentinel-2 displacement maps with as small time spans as possible, at the same time, keep as much as possible redundancy in the network to be able to construct a common master displacement time series by inversion 3) follow the previous strategy but use all available displacement maps from 3 sensors, with different temporal sampling and measurement precision taken into account. Afterwards, the common master displacement time series will be analysed by a data mining approach in order to extract unusual spatio-temporal patterns in the time series.
Assimilating visible radiances to constrain aerosol properties in the ECMWF Integrated Forecast System.
Authors: Thomas Gareth , Benedetti Angela , Quesada Ruiz Samuel , Letertre-Danczak Julie , Matricardi Marco
Published: March 2020

The Aerosol Radiance Assimilation Study (ARAS) has created a new approach for the assimilation of visible/near-IR radiances into the ECMWF’s Integrated Forecast System (IFS) for the constraining aerosol properties within the model. The capability is based on a new observation operator, based on the forward model used in the Optimal Retrieval of Aerosol and Cloud (ORAC) retrieval scheme, which predicts top-of-atmosphere radiances based on the model's aerosol field with sufficient accuracy while being computationally efficient enough to run in a operational analysis system such as that run at ECMWF. The system has been tested in the full IFS assimilation system, replacing the currently operational assimilation of MODIS AOD products, using MODIS radiances.
This presentation will give an overview of the new operator, show example results of its impact on the model output and discuss its merits and disadvantages compared to the AOD assimilation. 
The Massive New Year 2020 pyroCb Event in Australia: Observations of Unprecedented Stratospheric Smoke
Authors: Fromm Michael , Kablick III George
Published: March 2020

The 2019/2020 fire season in Australia has been unusually energetic since early spring. In the last days of December and early January an unprecedented number of pyrocumulonimbus (pyroCb) storms erupted in New South Wales and Victoria, creating a seemingly unrivaled stratospheric smoke plume as well as devastation on the ground. Preliminary indications from satellite remote sensing are that the clustering of active pyroCbs and smoke injection heights exceeded all previous Australian pyroCb events, and perhaps pyroCb events worldwide. Similar to another extraordinary pyroCb event, the so-called Pacific Northwest Event in 2017, the Australian smoke plume has been observed to rise above its injection altitude by several kilometers. We report on the active blowups and quantify the impact on stratospheric composition using satellite remote sensing. Our analysis also consists of a quantitative comparison of the 2019/20 Australian pyrocb event with other major pyroCb events such as Black Saturday, Victoria, Australia in 2009. At the time of submission of this abstract, this is an unfolding episode; our report will characterize the unusual nature of this pyroCb event as the evolving plume and satellite remote sensing data permit.
Optimizing CO emissions from the 2018 Californian fires using S5P – an inverse modelling study
Authors: Nüß Johann Rasmus , Daskalakis Nikos , Schneising Oliver , Buchwitz Michael , Krol Maarten C. , Vrekoussis Mihalis
Published: March 2020

A clear understanding of carbon monoxide (CO) emissions is important at various scales. On the local scale CO is toxic to living organisms, and on the global scale CO plays in role in the budget of  the hydroxyl radical (OH). OH, in turn, is important for the oxidizing capacity of the atmosphere. Additionally, CO is a precursor of the greenhouse gases ozone and carbon dioxide, hence CO influences also climate on a global scale.

Approximately one quarter of the global atmospheric CO load emanates from wildfires. However, these emissions are sometimes underrepresented in the emission datasets. Among the reasons for this discrepancy are clouds and smoke plumes hampering observations of land cover and active fires and uncertainties in emission factors. These issues are less relevant for top-down approaches like inverse modeling, which allow tracing back an atmospheric signal to its source even if it is only observed days after emission.

In this study, we attempt to improve the emission estimates of an existing inventory by applying an inverse modeling approach to the CO emissions of the California wildfires in 2018, that devastated more than 7500 square kilometers of forested and residential area. More specifically, we used the Fire Emission Inventory from NCAR (FINN) together with the CO observations from the TROPOMI instrument onboard the Sentinel 5 Precursor (S5P) satellite and the TM5-4dvar inverse model. The high resolution of the TROPOMI observations enables better spatial constraints compared to previous instruments. Preliminary results suggest significant positive emission increments compared to FINN.
The Digital Cultural Change within the Program Hamburg Open Science
Authors: Scharffenberg Martin , Olschofsky Konstantin
Published: March 2020

Transparency in Hamburg's scientific community, the further development of Hamburg as a university location, open access to research results, and secure long-term data storage are the main objectives of the Hamburg Open Science program. Hamburg Open Science bundles eight inter-university projects to promote open science at Hamburg's six state universities, the University Medical Center Hamburg Eppendorf and the Hamburg Carl von Ossietzky State and University Library.

The program is funded by the city of Hamburg for the period 2018-2020 and is supported by the Ministry of Science, Research and Equality. The eight projects science data management, science information system, open access repositories, archive data storage, modern publishing, web platform, 3D and audio visual science data, and the digital cultural change are developing the basis for the long-term operation of Open Science services from 2021 onwards. The web platform www.openscience.hamburg.de provides access to research results from Hamburg and is to be expanded into an information platform on science in Hamburg.

The idea of Open Science in the program context is that the digitalization of science enables a complete redesign of basic science principles and turning them into reality under the principles of transparency, reproducibility, reusability, open communication and exchange.

Therefore, the project aims of the digital cultural change are to create an awareness of open science among researchers and to integrate openness into their everyday work so that they can continue to focus on their research. The Hamburg Open Science program thus supports all orientations of Open Science by actively supporting scientists in their working methods, structures and behavior patterns towards open science.
Saltwater intrusion in delta regions around the globe
Authors: Götte Jonas , Thorslund Josefin , Wanders Niko
Published: March 2020

Saltwater intrusion into estuaries is a natural phenomenon which impacts freshwater availability for irrigation and human consumption. The intrusion length is dependent on the river discharge, sea level fluctuation and deltaic shape. As climate change impacts the sea level fluctuations and river discharge in many areas in the world it is expected that the intrusion length of rivers will change in the coming decades. However, global scale assessments are currently lacking, since estimates of the intrusion length are usually done for individual rivers, with complex models requiring extensive spatio-temporal data.
In this study, we provide a first global estimate of saltwater intrusion in estuaries. To do this, we first evaluate an existing predictive model for the salt water intrusion length on a local scale, before transitioning to global input data of river discharge, deltaic shapes and sea level. We assess the predictive quality of the model and its sensitivity in regard to uncertainties in (global) input data before giving an estimate of salt intrusion globally.
By using large ensemble-simulations of discharge on a global scale in a warmer climate (+2 °C), we further project impacts of climate change on the saltwater intrusion length and identify highly affected delta systems. The ensemble-simulations allow extreme events and respective estimations of frequency and magnitude. This is especially relevant since high salinity levels usually occur during droughts when river discharge is low and freshwater resources are diminished.
The digital zenith camera as an additional technique for quasi-geoid model determination of Latvia
Authors: Morozova Katerina , Silabriedis Gunars , Zarins Ansis , Balodis Janis , Jaeger Reiner
Published: March 2020

The digital zenith camera VESTA (VErtical by STArs) was designed by the Institute of Geodesy and Geoinformatics (GGI) of the University of Latvia and completed in 2016. By 2020 more than 400 terrestrial vertical deflection measurements were observed in the territory of Latvia. These observations were post-processed by the GGI developed software and the accuracy was evaluated at 0.1 arc seconds. In 2019 two new cameras have been developed, which will be used in future projects, e.g., in determination of properties of local geological structure or Earth crust movement monitoring. Measurement control software corrections and complements, data processing improvements and automation and transition to GAIA data release 2 star catalog were done. The accuracy of the measurements of improved camera was evaluated at 0.05 arc seconds.

Terrestrial vertical deflection observations were compared with global geopotential models, e.g. GGM+ and EGM2008. The results show a better correspondence with GGM+ model by evaluating the standard deviation: 0.314 and 0.307 arc seconds for ξ and η components respectively in comparison to 0.346 and 0.358 arc seconds for ξ and η components for EGM2008 model. The comparisons of average and minimum/maximum differences are introduced in this study for better evaluation of the results. Moreover, vertical deflections have been used as additional terrestrial data in DFHRS (Digital Finite-element Height Reference Surface) software v. 4.3 in combination with GNSS/levelling data (B, L, hH) and global geopotential model EGM2008 for gravity field and quasi-geoid improvement (www.dfhbf.de). This approach is based on parametric modelling and computation of height reference surfaces (HRS) from geometric and physical observation components in a hybrid adjustment approach. The results of the computed quasi-geoid models using different types of data are introduced in this research, representing several solutions, as well as these solutions are compared with the national quasi-geoid model LV’14.
Three Approaches to Interseismic Slip Rates on the Marmara Faults and Their Tensorial Correlations with the Kostrov-Based Strain Rates
Authors: Özbey Volkan , Özeren Mehmet Sinan , Henry Pierre , Klein Elliot , Galgana Gerald , Lange Dietrich , Royer Jean-Yves , Ballu Valerie , Çakır Ziyadin
Published: March 2020

The interseismic slip distribution in the Marmara fault system represents both observational and modelling challenges. The observational challenge is obvious: the faults are under water and to understand their interseismic behavior (creeping versus locked) requires expensive and logistically difficult underwater geodetic measurements, alongside those on land. Up to now, two such underwater studies have been conducted and they suggest that the segment to the south of Istanbul zone (so-called Central segment) is locked while some creep is probably going on along the neighboring segment to the west. Given these two important findings, the slip distribution problem is still non-trivial due to the fact that our experiments so far demonstrate that the block-based slip inversions and those that only consider a single fault (with the same geometry as one of the boundaries of the blocks) give significantly different results. In this study we approach the problem using three methodologies: block models with spatially non-varying strains within individual blocks, a boundary element approach and a continuum kinematic approach. Although the block model does not give spatially varying strains, the inversion results from the block model can be used as an input to model strain field in the vicinity of the fault. We constract a formulation to correlate the results from these with the strain rates obtained using focal mechanism summations.

GPS velocities are taken from previous studies around the Marmara Sea such as Reilinger et al., (2006), Aktuğ et al., (2009), Ergintav et al., (2014), Özdemir et al., (2016) and Özdemir and Karslıoğlu, (2019). Since all studies have different processing strategies or by choosing different reference frames, the GPS velocity fields could not be combined directly. Hence, we combined all velocity fields by minimizing the residuals between the velocities of the common sites in the studies. For this purpose VELROT program (Herring et al 2015) was used. Reilinger et al., (2006) was selected the reference field and other velocity fields were aligned one by one on it. If the combined sigma of the pairs of velocity estimates in the residuals are greater than 2 mm yr-1, that sites are excluded from the final velocity field. As a result, 127 GPS velocities were used in the developed models.
Azimuthal anisotropy of Rayleigh waves across a gas chimney structure
Authors: Parkes Lou , Chapman Mark , Curtis Andrew , Minschull Timothy A. , Bull Jon M. , Henstock Timothy , Bayrakci Gaye , MacDonald Calum
Published: March 2020

Gas chimneys are locations where natural gas leaks from the subsurface causing seabed pockmarks and potentially creating leakage pathways from CO2 storage or other subsurface reservoirs. The CHIMNEY project seeks evidence of changes in anisotropy between a gas chimney and the surrounding sediments, which would corroborate theories on the chimney permeability being caused by fractures.

Twenty-five ocean bottom seismometers (OBSs) were placed in an asterisk-shaped array over the Scanner pockmark in the UK License Block 15/25 in the North Sea and at a reference location ~1.5 km away. The OBSs recorded for several days while an active source survey was undertaken. Rayleigh wave data were also available from ambient seismic noise observed by using a low pass filter to remove active sources from the data.

We use 2D beamforming to observe the azimuthal dependence of the Rayleigh wave phase velocity. 2D beamforming uses radon transforms summed over time for a range of different azimuths which gives the distribution of wave energy passing across an array as a function of group velocity.

Using narrowly band-passed data for the beamforming, we observe phase velocities of 250 - 650 m/s in the 0.8 - 1.2 Hz range. Initial results show θ, 2θ and 4θ anisotropy components in the measured phase velocities at the frequencies with the best ambient sources. We observe different fast orientations at the reference site than the chimney site. Varying anisotropy between the two sites supports the hypothesis that there is different fracturing in the chimney than in the surrounding geology.

With lower frequency surface waves penetrating deeper into the subsurface, dispersion of surface waves provides information about velocity variations with depth. Despite the array aperture imposing a lower limit on observable frequencies at around 0.7 Hz and noise source availability imposing a higher limit of about 1.2 Hz, strong dispersion was evident at both sites within this frequency window. The orientation and degree of anisotropy also appears to vary with frequency, indicating a variation in velocity and anisotropy with depth.

This work was undertaken with funding from NERC through the E3 Doctoral Training Partnership (E3 DTP; NE/L002558/1). The data was acquired with funding from the NERC (CHIMNEY; NE/N016130/1) and EU Horizon 2020 programme (STEMM-CCS; No.654462).
Microphysical features indicated by GPM DPR product “flagHeavyIcePrecip” – Case studies on lightning activity
Authors: Suzuki Kenji , Kamamoto Rimpei , Kawano Tetsuya , Nakagawa Katsuhiro , Kaneko Yuki
Published: March 2020

Two products from the Global Precipitation Measurement (GPM) Dual-frequency Precipitation Radar (DPR) algorithms, a flag of intense solid precipitation above the –10°C height (“flagHeavyIcePrecip”), and a classification of precipitation type (“typePrecip”) were validated quantitatively from the viewpoint of microphysics using ground-based in-situ hydrometeor measurements and X-band multi-parameter (X-MP) radar observations of snow clouds that occurred on 4 February 2018. The distribution of the “flagHeavyIcePrecip” footprints was in good agreement with that of the graupel-dominant pixels classified by the X-MP radar hydrometeor classification. In addition, the vertical profiles of X-MP radar reflectivity exhibited significant differences between footprints flagged and unflagged by “flagHeavyPrecip”. We confirmed the effectiveness of “flagHeavyIcePrecip”, which is built into “typePrecip” algorithm, for detecting intense ice precipitation and concluded that "flagHeavyIcePrecip" is appropriate to useful for determining convective clouds.

It is well known that the lightning activity is closely related to the convection. We examined the lightning activity using GPM DPR product flagHeavyIcePrecip that indicates the existence of graupel in the upper cloud. On 20 June 2016, we experienced heavy rain with active lightning during Baiu monsoon rainy season, while the GPM DPR passed over Kyushu region in Japan. The distribution of “flagHeavyIcePrecip” obtained from the GPM DPR well corresponded to the CG/IC lightning concentration. On 4 September 2019, isolated thunder clouds observed by the GPM DPR was also similar to the “flagHeavyIcePrecip” distribution. However, partially there was IC lightning without “flagHeavyIcePrecip”, which was positive lightning. It was suggested to have been produced in the upper clouds in which positive ice crystals were dominant.
Supporting Users to Find Appropriate Visualizations of Spatio-Temporal Open Data Sets
Authors: Schulte Jan , Zepner Laura Helene , Mäs Stephan , Jirka Simon , Sauer Petra
Published: March 2020

Over the last few years, a broad range of open data portals has been set-up. The aim of these portals is to improve the discoverability of open data resources and to strengthen the re-use of data generated by public agencies as well as research activities.

Often, such open data portals offer an immense amount of different types of data that may be relevant for a user. Thus, in order to facilitate the efficient and user-friendly exploration of available data sets, it is essential to visualize the data as quickly and easily as possible. While the visualization of static data sets is already well covered, selecting appropriate visualization approaches for potentially highly-dynamic spatio-temporal data sets is often still a challenge.

Within our contribution, we will introduce a preliminary study conducted by the mVIZ project which is funded by the German Federal Ministry of Transport and Digital Infrastructure as part of the mFUND programm. This project introduces a methodology to support the selection and creation of user-friendly visualizations for data discoverable via the open data portals such as the mCLOUD. During this process, specific consideration are given to properties and metadata of the datasets as input for a decision workflow to suggest appropriate visualization types. A resulting guideline will describe the methodology and serve as a basis for the conception, extension or improvement of visualization tools or for their further development and integration into open data portals.

The project focuses particularly on the creation of an inventory of open spatiotemporal data in open data portals as well as an overview of available visualization and analysis tools, the development of a methodology for selecting appropriate visualizations for the spatio-temporal data, and the development of a demonstrator for supporting the visualization of selected data sets.
Response of N2O emissions to logging residue piles of Norway spruce, Scots pine and silver birch
Authors: Törmänen Tiina , Lindroos Antti-Jussi , Kitunen Veikko , Smolander Aino
Published: March 2020

Utilization of forest bioenergy is increasing; however, the overall environmental impacts of forest bioenergy utilization are not fully understood. Especially effects on N2O emissions in mineral soils are less studied. With current harvesting practices, either whole-tree-harvest or stem-only-harvest, piles of logging residues are left on the forest floor. As a result, soil nitrogen (N) cycling processes can be accelerated on clear cut area under the piles, especially net nitrification. When N is transformed to more mobile form, the risk for N losses via nitrous oxide (N2O) emissions from the forest floor may increase.

We studied how logging residue piles of three tree species, Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth.), influence gaseous losses of N after clear-cut. A Norway spruce dominated mixed stand on a mineral soil site was clear-cut and N2O emissions were monitored. There were four treatments; three tree species treatments consisting of 40 kg m-2 of fresh logging residues and control plot without residues as an additional treatment. Effects of logging residue piles on N2O emissions were monitored over 4 growing season with closed chamber technic. Simultaneously soil temperatures were recorded over 2 growing season. Soil denitrification activity and the contribution of nitrification and denitrification to N2O production were determined in laboratory experiments.

Logging residue piles lowered and balanced fluctuation of soil temperatures. N2O fluxes peaked under the piles during the second and third growing season after the establishment of the piles; however inconsistent fluxes tended to be low. The production of N2O was driven by both nitrification and denitrification processes, the proportion depending on the tree species. Our results indicate that logging residue piles accelerate N losses as gaseous form; however studies on the same field experiment shows that most of the N losses occur through soil percolation waters. Spruce residues tend to stimulate N2O emissions longer compared to other tree species. There was a positive correlation with net nitrification and microbial biomass C (Törmänen et al. 2018, FORECO). These results have implications for sustainable and productive forest management practices and nutrition of re-growing vegetation.