bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying the uncertainty in the prediction of soil properties from soil-spectra using local and regional spectral libraries
Authors: Breure Timo , Milne Alice , Webster Richard , Haefele Stephan M. , Hannam Jacqueline A. , Corstanje Ronald
Published: March 2020

Spectral measurements are increasingly used to predict soil properties. Libraries of soil spectra are built and statistical models are used to relate the spectra to wet chemistry measurements. These relationships can then be used to predict the properties of new samples. An important  consideration is the uncertainty associated with the prediction. Often to reduce this error calibration is done at field level. This is time and resource intensive, however, and there is scope to use existing spectral libraries. Our aim was to quantify the uncertainty in the prediction of soil properties from spectral measurements using a local library and compare this to predictions made using a regional library.   

To investigate this, we considered two case study fields in the Cambridgeshire fens (UK) that were planted with lettuce. These fields contain complex soils which are a combination of peat with underlying alluvial and marine silts that became elevated features in the landscape due to peat oxidation and shrinkage. These elevated features are captured by a 2 m x 2 m LiDAR raster used in our study (UK Environment Agency). We took a total 467 soil samples across the fields and made spectral measurements (near- and mid-infrared). A subset of the soil samples underwent wet chemistry analysis for available pH, P, K, total N and soil particle size fraction. For the regional library we use soil the National Soil Inventory spectral database and its respective wet chemistry reference values.

We used partial least squares to regress the soil spectra for the local and regional spectral libraries against the wet chemistry reference values. These two models were then used to predict the soil properties for both fields. We then mapped the variation in each soil property and the associated uncertainty by kriging.  The variation in some of the soil variables was clearly affected by elevation and there were signs of spatial trend and so we used universal kriging to map the soil properties. To reduce bias, we used residual maximum likelihood estimation (REML) to estimate the variogram by fitting a linear mixed model with the trend accounted for as fixed effects.  We compared these different maps to assess how the calibration regression from local and regional spectral libraries translates itself in uncertainty of kriged maps for five different soil properties within each field.

 
How will the Greenland Ice Sheet develop under Extreme Melt Events?
Authors: Beckmann Johanna , Delhasse Alison , Winkelmann Ricarda
Published: March 2020

In the past years, Greenland has been affected by several extreme melt
events, particularly in the years 2010, 2012 and most recently, during
this year's spring/summer. With progressing climate change, extreme melt
events can be expected to occur more frequently and become more
severe/persistent. So far, however, longer-term projections of ice loss
from Greenland typically rely on scenarios that only take account of
gradual changes in the climate, for instance, based on the
Representative Concentration Pathways. Extreme melt events have
generally been underestimated and their potential effect on future
surface mass balance shows already serve impacts for sea-level rise.

Here we investigate the total impact of future extreme melt events on
the Greenland Ice Sheet. We force the thermodynamically coupled parallel
ice sheet model PISM with idealized surface-mass-balance scenarios that
include extreme melt events. Thereby, we investigate the dynamical
response of the ice sheet model to changes in frequency and intensity of
extreme melt events and quantify their impacts with respect to sea-level
rise.

 
Projected change in frequency of Weather Regimes in CMIP6 models
Authors: Fabiano Federico , Giuntoli Ignazio , Ghinassi Paolo , Corti Susanna
Published: March 2020

Weather Regimes (WRs) are preferred large-scale atmospheric circulation patterns found in mid-latitude regions like the North-Atlantic or North-Pacific, that have a certain degree of recurrence and persistence. From a nonlinear dynamical system view, they can be seen as the attractors of the chaotic atmospheric flow at mid-latitudes. In simple nonlinear dynamical systems, under a small external forcing the attractors remain fixed at first-order, but the frequency of occurrence of the different dynamical regimes changes, with some regimes becoming more populated. By analogy, a similar response to forcing has also been hypothesized for the WRs in complex GCMs. Here we test this hypothesis in the climate models participating to CMIP6, looking for the change of the WRs frequency in the future climate (2050-2100) under different scenarios, with respect to the historical simulations (1964-2014).

WRs also constitute a suitable framework to study the impacts and occurrence of extreme weather. In this sense, each WR is characterized by a large-scale circulation pattern, that drives different climatic conditions over specific regions, and long-lasting WRs are often connected with extreme temperature or precipitation anomalies. Therefore, the projected change in the frequency of the WRs also produces an intensification of the impacts connected with the regimes occurring more often. For each model analyzed, we also study the impacts related with each WR and their change with future climate under the different scenarios.
Spatio-temporal Patterns of the Precipitation Response to Aerosol Perturbations from an Energetic Perspective
Authors: Zhang Shipeng , Stier Philip , Watson-Parris Duncan , Dagan Guy
Published: March 2020

Absorbing and non-absorbing aerosols have distinct effects on both global-mean and regional precipitation. Local changes of precipitation in response to aerosol perturbations are more complex than global-mean changes, which are strongly constrained by global energy budget. This work examines the changes of atmospheric energetic budget terms to study effects of large perturbations in black carbon (BC) and sulphate (SUL) on precipitation. Both cases show decrease of global-mean precipitation but with different geographical patterns. Decreased atmospheric radiative cooling contributes to the majority of decreased global-mean precipitation. It is caused by increased aerosols absorption in BC case but decreased cooling from clean-clear sky (without clouds and aerosols) in SUL case. Fast responses, which are independent of changes in sea surface temperature (SST), dominate the precipitation changes in the BC case, not only for global mean but also for regional patterns. Slow responses, which are mediated by changes in SST, dominate the precipitation responses in SUL case, both globally and regionally.

 

Relationships between temporal responses of local precipitation and diabatic cooling and precipitation are also examined for both BC and SUL perturbations. Both cases show remarkable similar pattern of correlations despite of essentially different patterns of changes in precipitation and diabatic cooling. Strong positive correlations are found over mid-latitude land and this is mainly due to the changes from surface sensible heat fluxes. Negative correlations are found over tropical oceans, mainly contributed by (longwave) radiative cooling from clouds and clean-clear sky. Further analysis shows this similarity is caused by the natural variability which is independent from external forcing. It indicates that the temporal relationship between changes in local precipitation and diabatic cooling is forcer-independent. This correlation is examined as a function of increasing spatial scales, which demonstrates the scale at which the dominating energetic term on regional precipitation shifts from energy transport to atmospheric diabatic cooling.
Environmental filmmaking workshops: Engaging university students on plastic pollution in Cambodia and Vietnam
Authors: Hackney Chris , Cumming Vivien , Waldman Robin
Published: March 2020

‘Proof of concept’ science communication workshops were organised in Phnom Penh, Cambodia and Hanoi, Vietnam focussing on capturing community perceptions on environmental issues. The aim was to help students on environmental courses learn quick and easy ways to make impactful short films so as to communicate their science to the public and their peers on social media, which is widely used in the region.  The workshops lasted a day and taught students how to find a story, film it and edit it into a 1-minute video, with the videos shown at the end of the day in a mini ‘film festival’ and then shared by the students. Our research involves looking at plastic pollution in the Mekong River. In order to publicise the problem to the general public in the region the workshops with local students allowed us to tell environmental stories on social media from their perspective and streamlined the process of communication, providing content that could be shared widely. The workshops were very successful, and we now have a tried and tested method of training scientists in regions of the world where crucial scientific research is being carried out to effectively engage with their colleagues, the general public and the media in their region.
Assessing the potential of urban soil for carbon sequestration by adding wheat straw pellets or wheat straw biochar
Authors: Wang Jiaqian , Werner David , Manning David
Published: March 2020

Higher Education in England targets to reduce by an average 34% carbon dioxide emissions until 2020 based on the level in 1990. This project not only requires various departments of universities to improve their energy system by utilizing low carbon techniques but also challenges the academics and researchers to examine multiple approaches to sequester carbon as much as possible in the limited area. Land owned by universities contains a lot of carbon. The group SUCCESS (Sustainable Urban Carbon Capture Engineering Soils for Climate Change) in Newcastle University has observed that 10 ha of urban soil near Newcastle Science Central removed almost 80 T CO2 per hectare every month.

The project has set up two lysimeters in June 2018 to investigate the addition of wheat straw pellets (WP) versus biochar (BC) produced from this biomas as carbon sequestration strategies. Sensors were set up at different depths to collect information about the internal soil environment. The wheat straw biochar has 69.04% C content, and it was applied to the soil at a rate of 2% (w/w); the application rate of wheat straw pellets is based on the carbon weight of wheat straw biochar. Therefore, the amount of carbon added as wheat straw pellets, or as wheat straw biochar was 29.8±0.57 Kg in each lysimeter.

Cumulatively, 704.23±0.14 g and 697.17±0.1 g of total carbon were leached from the lysimeter BC and lysimeter WP, respectively, till the end of November 2019. Meanwhile, the total amount of CO2 carbon released via respiration of soil carbon was 9.65±0.35 Kg and 6.17±0.19 Kg for lysimeter BC and lysimeter WP, respectively, from August 2018 to November 2019. Moreover, the carbon mass fixed, measure as dried grass biomass in the two systems was 1.57 Kg for lysimeter BC and 1.75 Kg for lysimeter WP. The net C mass stored according to the mass balance for the lysimeter BC is 21.02 ±0.67 Kg from the topsoil during the experiment period, and 24.68±0.6 Kg in lysimeter WP. Whereas, by measurement, the amount of carbon in the topsoil has shown an increase of 37.09±13.58 Kg and 19.51±3.36 Kg in lysimeter BC and lysimeter WP, respectively. Currently, the data obtained in this study indicate that the mixture of biochar and biomass amendment promotes carbon sequestration potential in the urban soil environment and further application details on land owned by the university can be explored.
THz imaging in the frame of the Archaeological Urban Park of Naples project
Authors: Catapano Ilaria , Noviello Carlo , Ludeno Giovanni
Published: March 2020

The Archaeological Urban Park of Naples (PAUN) project aims at addressing the need of analytical information relating to cultural heritage with modalities that encourage innovation systems of protection and enhancement. In this frame, one of the specific goals is the testing of multiple non-invasive or only minimally invasive investigation techniques, aimed at identifying a permanent diagnostic system calibrated to the specific context of the Urban Archaeological Park of Piazza Municipio, Napoli, Italy.

Among the electromagnetic sensing technologies, those exploiting Terahertz waves (1THz = 1012 Hz) are the newest among the imaging techniques, which offers the attractive chance of characterizing the inner features of manmade objects with a sub-millimeter spatial resolution in a non-invasive way while assuring negligible long-term risks to the molecular stability of the exposed objects.

This possibility together with the recent development of compact, transportable and easily reconfigurable devices make THz imaging a more and more widespread considered investigation tool in the frame of cultural heritage. THz imaging allows, indeed, the gaining of information useful to improve knowledge about the design technique adopted by the artist and to detect possible damages affecting the conservation state of precious artworks [1].

In the frame of PAUN project, THz imaging is considered as part of the sensor network, which is dedicated to the material characterization and supports the conservation and use of the assets of the Urban Archaeological Park of Piazza Municipio. Specifically, THz imaging is adopted to analyze ancient decorated mortar specimens and gather information on their stratigraphy. At this regard, it is worth pointing out that the effectiveness of THz imaging, i.e. the capability of obtaining high resolution images of the object under test, is dependent not only on the performances of the hardware technology but also on the data processing approaches. Herein, we consider the time domain Z-Omega Fiber-Coupled Terahertz Time Domain (FICO) system, which is available at IREA-CNR, and a data processing chain specifically designed to improve the discrimination of different material layers and to reconstruct the inner features characterizing the investigated artworks [2].

 

[1] Fukunaga, THz Technology Applied to Cultural Heritage in Practice, Cultural Heritage Science, Springer.

[2] Catapano, I., Soldovieri, F. A Data Processing Chain for Terahertz Imaging and Its Use in Artwork Diagnostics. J Infrared Milli Terahz Waves 38, 518–530 (2017).

 

Acknowledge: Authors would like to thank the PAUN project “Archaeological Urban Park of Naples” by which the present work has been financed.

 
Dynamic connectivity as a determinant of the resilience of stream habitat to geomorphic perturbation
Authors: Lane Stuart
Published: March 2020

One of the primary challenges of understanding hydro-geomorphic connectivity is to move from static to dynamic representations of connection. This is particularly important when linkages are made between hydro-geomorphic connectivity and habitat. In response to external drivers, notably extreme events, the spatial locations of suitable habitat within an ecosystem may migrate spatially, potentially rapidly. A resilient ecosystem, in one sense, is one where organisms can either “weather-it-out” or migrate to newly suitable habitat to find temporary refuge from those extreme events. In this paper, I show that is it the spatio-temporal evolution of connectivity that determines the resilience of braided stream ecosystems to geomorphic perturbation. Using a validated model of the spatial distribution of instream macroinvertebrate habitat, that combines both known organism preferences with the risks of geomorphic perturbation, I show that during high flow events, suitable habitat shifts rapidly from the primary braid plain channels to secondary ones. The connectivity between primary and secondary channels determines the extent to which secondary channels can be used as refugia; but this connectivity varies continually during the flow event. This can be captured in connectivity metrics based upon notions of percolation. The work has important implications for stream management. First, it shows that the availability of habitat within an ecosystem at high flows is not a sufficient descriptor of the system resilience. The ability of organisms to access suitable habitat as flow rises, and to return to the low flow channel as it falls, is critical; connectivity is primordial. Second, it emphasises that a focus on connectivity as a static state or metric is not sufficient to describe the extent to which a system is resilient. The accessibility of habitat suitable zones at high flows depends upon the how connectivity evolves during the event, which controls accessibility. Thirdly, analyses of connectivity, and wider assessment of stream resilience, need to couple geomorphology and hydrology, and not just focus on environmental flows. The latter provide only a very partial representation of connectivity.
The influence of the heterogeneous asperity distribution on induced seismicity and permeability evolution during hydraulic fault zone stimulation
Authors: Villiger Linus , Zbinden Dominik , Rinaldi Antonio Pio , Selvadurai Paul Antony , Krietsch Hannes , Gischig Valentin , Doetsch Joseph , Jalali Mohammadreza , Amann Florian , Wiemer Stefan
Published: March 2020

Several decameter-scale in-situ stimulation experiments were conducted in crystalline rock at the Grimsel Test Site, Switzerland, with the aim to advance our understanding of the seismo-hydro-mechanical processes associated with deep geothermal reservoir stimulation. To allow comparability between the experiments, a standardized injection protocol was applied for all experiments. Induced seismicity was recorded using acoustic emission sensors and accelerometers, which were distributed along tunnel walls and within four boreholes. Hydro-mechanical responses of the fault zones were measured using grouted longitudinal fiberoptic strain sensors and open pressure monitoring borehole intervals. A total of four ductile shear zones (with brittle overprint) and two brittle-ductile shear zones have been stimulated during these experiments.

Here we present an analysis of heterogeneous permeability evolution within a target shear zone during ongoing stimulation. The shear zone in question is an originally ductile shear zone which contains a single fracture in the injection interval. The observed planar seismicity cloud indicates that most of the stimulation process was confined within the target shear zone. Hydraulic characterization of the injection interval before and after stimulation revealed an enhancement in interval transmissivity from 8.3-10-11 m2/s to 1.5-7 m2/s. Within the reservoir, the seismo-hydro-mechanical data (i.e. seismicity cloud, pressure peaks and local deformation) spatiotemporally coincide, suggesting that permeability enhancement along the shear zone is highly localized and heterogeneous. Thus, we argue that the permeability evolution is linked to asperity distribution and breakdown within the shear zone.

The conceptual model developed from the experimental analysis is implemented in a three-dimensional numerical model, with which we attempt to simulate the directional permeability creation observed in the experiment. The model accounts for a discrete planar fault zone of finite thickness with distributed low-permeability, brittle asperities embedded in a more permeable damage zone mimicking the ductile shear zone at Grimsel. The hydro-mechanical processes are modeled with the TOUGH-FLAC simulator, which sequentially couples fluid flow and poroelastic deformation within the fault and the surrounding medium. A Mohr-Coulomb failure criterion is used to simulate asperity reactivation, which can lead to permeability enhancement of the reactivated area.
Towards highly-sparse, autonomous imaging systems: high-resolution wavefield imaging for frontier exploration
Authors: Vasconcelos Ivan , Ruan Jingming , Kuijpers Dieuwertje , Ravasi Matteo , Putzky Patrick
Published: March 2020

Can we image and monitor the internal ocean structure at global scales? Can we monitor in vast expanses of the Earth’s cryosphere subsurface with meter-length resolution? Can we characterize the interior structures of asteroids and comets out in space efficiently and with high confidence? At the core of these questions lies the understanding and development of wave-based imaging systems, based on seismic or radar, that rely on highly-sparse, high-quality data, but whose output image quality is comparable to that of densely sampled, wide aperture array-based data. Traditionally, exploration seismology has long relied on wide aperture, dense data sets together with high-end imaging such as reverse-time migration and full-waveform inversion to produce high resolution subsurface models. Given the recent rise of drone-like, autonomous systems, in this talk, we present approaches that can take highly-sparse data as would be recorded by autonomous platforms, into accurate high-resolution images as if they had been acquired by densely-sampled, wide aperture source and receiver arrays. We demonstrate two approaches that could achieve this goal. The first is the use of sparse multicomponent sources and receivers capable of exciting/recording fields and their spatial gradients, together with a gradient-based wavefield reconstruction approach and subsequent imaging. The second approach relies on a new deep learning architecture, the so-called Recurrent Inference Machine, designed specifically for inverse problems – showing that it can surpass the capabilities of deterministic approaches to data reconstruction and imaging. We illustrate these approaches using a numerical model for oceanic turbulence, where we show the compressive sensing potential of these acquisition, reconstruction and imaging methods for acoustic imaging of the ocean's internal structure – overcoming current limitations in data acquisition and processing for seismic oceanography. Finally, we postulate that these approaches, though still in their early days, will pave the way in enabling breakthrough imaging systems at the frontiers of geo-imaging, e.g., for oceanography at global scales, in imaging the Earth’s cryosphere or for planetary exploration.
Variability of Subsurface and Intermediate Currents in the Western Equatorial Pacific Ocean and Their Impacting Factors
Authors: Tang Xiaohui , Wang Fan , Lyu Yilong
Published: March 2020

Based on direct current measurements by ADCP moorings conducted during 2014-2018, seasonal-to-interannual variabilities of the Western Equatorial Pacific currents in different depth layers are analyzed. GODAS, Tropflux and NCEP reanalysis2 data are used to study the climatological factors influencing the current variabilities. The results show that both Equatorial Under Current (EUC) and Equatorial Intermediate Current (EIC) have significant seasonal-to-interannual variabilities. Both are closely related to the ENSO cycle, but through different mechanisms. Variations of the zonal velocity of Western Pacific EUC have noticeable correlations with subtropical SST, SLP and wind velocity, suggesting an influence of the Pacific meridional mode. The EIC, however, changes basically in corresponding to the Pacific zonal mode (ie. canonical ENSO mode). ENSO signals of the Eastern Equatorial Pacific might impact the Western Pacific EIC through vertical propagation of Rossby wave. This study gives an example on how atmospheric signals influence the subsurface ocean currents up to 800m depth.
Structure and transport of Atlantic water north of Svalbard from observations in summer and fall 2018
Authors: Hugaas Kolås Eivind , Koenig Zoe , Fer Ilker , Nilsen Frank , Marnela Marika
Published: March 2020

The transport of warm Atlantic waters north of Svalbard is one of the major heat and salt sources to the Arctic Ocean. The circulation pathway and the associated heat transport influence the variability in the Arctic sea ice extent and the onset of freezing. We present observations obtained from research cruises and autonomous underwater glider missions in summer and fall 2018 to describe the hydrographic structure, volume transport rates and circulation patterns of the warm boundary current between 12E and 24E north of Svalbard.

A composite section is constructed along a representative, average bathymetry across the shelf break, using all available observations in order to obtain the hydrographic structure and the absolute geostrophic transport of the boundary current. The Atlantic water volume transport reaches a maximum of 3.0 ± 0.2 Sv in October, with an intraseasonal variability of 1 Sv. During summer and late fall, we observed Atlantic water flowing eastward (a counter current), in the outer part of the section away from the shelf break, in the Sofia Deep. The intensity of the Atlantic water counter current and the Atlantic water boundary current are very sensitive to the wind stress curl: we observed a near doubling of the volume transport in less than a week.

The composite section also reveals a bottom-intensified current flowing parallel to the boundary current, between the 1500 m and 2000 m isobaths. A composite of all historical data collected in the region, constructed identical to our observations, support the presence of the bottom intensified current.
Climate-change-induced changes in steep alpine permafrost bedrock. 13 years of 3D-ERT at the Steintälli ridge, Switzerland.
Authors: Scandroglio Riccardo , Krautblatter Michael
Published: March 2020

Warming of mountain permafrost leads to growth of active layer thickness and reduction of rock wall stability. The subsequent increase of instable rock volumes can have disastrous or even fatal consequences, especially when cascading events are simultaneously triggered. This growth of climate-change-connected hazard, together with the recent increase of exposition of infrastructure and people, poses the alpine environments at a high risk, which needs to be monitored. Laboratory-calibrated Electrical Resistivity Tomography (ERT) has shown to provide a sensitive record for frozen vs. unfrozen conditions, presumably being the most accurate quantitative permafrost monitoring technique in permafrost areas where boreholes are not available.

The data presented here are obtained at the Steintälli ridge in Switzerland, which presents highly vulnerable permafrost conditions. A consistent 3D field set-up, the robust temperature calibration and the quantitative inversion scheme allow to compare measurements from the longest time series (2006-2019) of ERT in steep bedrock. A direct link to mechanical changes measured with tape extensometer is provided. Comparison of repeated hourly measurements as well as Wenner and Schlumberger arrays are also shown here, in order to increase the robustness of the delivered results.

Confirming the long-term observation from air temperatures, results from multiple parallel transects show an average resistivity reduction of 22%, concentrated at deeper layers of the permafrost lens. The permafrost area in the 3D cross sections also decreased from 30 to 10% (about 500 to 150m2 in our transects), with losses mainly localized on the south-east part of the study site, but in some cases also extending to the north face. 
The impact of Ignalina Nuclear Power Plant on Carbon-14 content in Lake Druksiai, Lithuania
Authors: Butkus Laurynas , Barisevičiūtė Rūta , Ežerinskis Žilvinas , Šapolaitė Justina , Maceika Evaldas , Garbaras Andrius , Pabedinskas Algirdas , Mažeika Jonas , Remeikis Vidmantas
Published: March 2020

Nuclear Power Plants (NPPs) and nuclear fuel reprocessing sites are main producers of anthropogenic radiocarbon. Anthropogenic 14C can be released into the environment in gaseous forms, with liquid effluents or with spent nuclear fuel [1]. During photosynthesis radiocarbon can be easily assimilated into the plants. As a result, carbon-14 can be transported through the food chain and accumulate in a human body. Therefore, radiocarbon is considered a primary source of increased human radiation dose from industrial nuclear activities [2].

Main goal of this research was to evaluate the influence Ignalina NPP on carbon-14 content in the Lake Druksiai. The sediment core was collected from the Lake Druksiai. The ages of sediment layers were estimated using 137Cs and 210Pb dating methods. ABA (acid-base-acid) chemical pretreatment procedure was used to extract humin (HM) and humic acid (HA) fractions from the sediments. Chemically pretreated samples were graphitized with the Automated Graphitization Equipment AGE 3 (IonPlus AG). Carbon-14 measurements in prepared samples were performed using the single stage accelerator mass spectrometer (SSAMS, NEC, USA).

Radiocarbon content was measured in the sediment core which covers all phases of the NPP exploitation (commissioning, operation and decommissioning). These measurements in HM and HA fractions showed that after the start of the operation of the Ignalina NPP in 1983, the 14C concentration in these organic fractions increased by 4 pMC and 3 pMC, respectively. In addition, a sharp increase of radiocarbon content (concentration almost doubled) in HA fraction was observed in the year 1999. Similar increase in 14C activity in fish samples from Lake Druksiai was measured. In HM fraction such drastic changes in radiocarbon concentration were not observed. These results suggest that 14C enriched effluents were released from the Ignalina NPP in 1999.

[1] Z. Ezerinskis et al., Annual Variations of 14C Concentration in the Tree Rings in the Vicinity of Ignalina Nuclear Power Plant, Radiocarbon 60, 1227–1236 (2018).

[2] IAEA, Generic Models for Use in Assessing the Impact of Discharges of Radioactive Substances to the Environment (2001).
Cloud Droplet Size Distributions from Observations of Glory and Cloudbow during the EUREC4A Campaign
Authors: Pörtge Veronika , Kölling Tobias , Zinner Tobias , Forster Linda , Mayer Bernhard
Published: March 2020

The cloud droplet size distribution determines the evolution of clouds and their impact on weather and climate. First, droplet size determines
the cloud radiative effect. Second, evolution of clouds and formation of precipitation are determined by droplet size and the shape of the size distribution. Therefore, measurements of the size distribution are important to further our understanding of clouds and their role in the earth system. We present a remote sensing technique for droplet size and width of the size distribution based on polarized observations of the glory and the cloudbow.
Glory and cloudbow are caused by backscattering of sunlight by spherical droplets in liquid clouds. This backscattering results in colorful concentric rings surrounding the observer’s shadow; the formation is described quantitatively by Mie theory. The rings of the glory appear in an angular range of 170° – 180° scattering angle and the larger cloudbow rings in a range of about 130° – 160° . The angular radius of the rings is the most accurate and direct measure of the droplet size at cloud edge. In addition, the sharpness of the rings conveys information about the width of the droplet size distribution. The visibility of glory and cloudbow is significantly enhanced by the use of polarized observations which reduce the contribution of multiple scattering.
The specMACS sensor of LMU Munich has been upgraded recently by a polarization-sensitive wide-angle imager which was operated for the first time on the HALO aircraft during the EUREC4A campaign. The newly installed sensor offers a high spatial and temporal resolution, allowing to study small-scale variability of cloud microphysics at cloud top with a resolution of about 20 m. specMACS measurements and first retrieval results using the glory-cloudbow technique are presented.
Simulation of methane point source emissions and their isotopic signatures using the global/regional climate model MECO(n).
Authors: Nickl Anna-Leah , Winterstein Franziska , Mertens Mariano , Kerkweg Astrid , Fiehn Alina , Gerbig Christoph , Galkowski Michal , Jöckel Patrick
Published: March 2020

Methane is the second most important anthropogenic greenhouse gas. The globally averaged dry mole fraction has increased considerably since pre-industrial times and its growth even accelerated in 2014, with an annual rise of 12.7 ± 6 ppb. Fossil fuel emissions are one of the primary sources. However, the quantification of methane sources and sinks is still under debate and estimates of anthropogenic emissions show large uncertainties on global and regional scales. Comprehensive measurement campaigns, such as CoMet 1.0 (May-June 2018), are therefore important for assessing climate change mitigation options. CoMet aimed to quantify point source emissions in the Upper Silesian Coal Basin (USCB), where roughly 502 kt/yr of methane are emitted due to coal mining. Differences in isotopic methane source signatures δ13C and δD can further help to constrain different source contributions (e.g. thermogenic or biogenic). We simulate methane isotopologues from localized coal mine emissions in the USCB using the on-line three times nested global regional chemistry climate model MECO(n). We use a submodel extension, which includes the kinetic fractionation and make different assumptions on the isotopic source signatures in the USCB. Here we show first results of these simulations and a comparison to flask samples taken during CoMet 1.0.
Flood risk and water resources management with nature-based solutions on Florence city environment
Authors: Pacetti Tommaso , Pampaloni Matteo , Castelli Giulio , Caporali Enrica , Bresci Elena , Isola Matteo , Lompi Marco
Published: March 2020

Increasing urbanization, evolving socio-economic scenarios and the impacts of climate change require innovative strategies to adapt urban and peri-urban environments, making them more resilient and sustainable. In this context, Nature Based Solutions (NBS), i.e. actions inspired or supported by nature, can be designed to adapt and provide integrated responses to the environmental, social and economic future challenges.

The FLORENCE (FLOod risk and water Resources management with Nature based solutions on City Environment) project evaluates the possibility of including NBS as an innovative tool for the management of the territory of the City of Florence (Firenze), Italy. The project develops a quantitative evaluation methodology that clarifies the benefits and co-benefits of NBS, highlighting the limitations and exploring the possible synergies with existing infrastructures.

Starting from the existing literature on the NBS siting, a set of parameters to be considered in order to map Ecosystem Services (ES) priority areas (main functions and co-benefits) is derived. This analysis is then coupled with the identification of the constraints (regulatory, urban planning, economic, environmental, social) which determine the boundary conditions for the inclusion of NBS in the Florence city urban environment. Once the most suitable implementation areas of NBS are identified, the hydraulic modeling of multiple NBS implementation scenarios using EPA SWMM is implemented. This allows the definition of the scenario that best respond to the city's green development needs and that maximize the production of ES.
Staying fair while being FAIR - challenges with FAIR and Open data and services for distributed community services in Seismology
Authors: Haslinger Florian , Consortium Epos Seismology
Published: March 2020

The European Plate Observing System EPOS is the single coordinated framework for solid Earth science data, products and services on a European level. As one of the science domain structures within EPOS, EPOS Seismology brings together the three large European infrastructures in seismology, ORFEUS for seismic waveform data & related products, EMSC for parametric earthquake information, and EFEHR for seismic hazard and risk information. Across these three pillars, EPOS Seismology provides services to store, discover and access seismological data and products from raw waveforms to elaborated hazard and risk assessment. The initial data and product contributions come from academic institutions, government offices, or (groups of) individuals, and are generated as part of academic research as well as within officially mandated monitoring or assessment activities. Further products are then elaborated based on those initial inputs by small groups or specific institutions, usually mandated for these tasks by 'the community'. This landscape of coordinated data and products services has evolved in a largely bottom-up fashion over the last decades, and led to a framework of generally free and open data, products and services, for which formats, standards and specifications continue to be emerging and evolving from within the community under a rather loose global coordination.

The advent of FAIR and Open concepts and the push towards their (formalized) implementation from various directions has stirred up this traditional setting. While the obvious benefits of FAIR and Open have been readily accepted in the community, issues and challenges are surfacing in their practical application. How can we ensure (or enforce) appropriate attribution of all involved actors through the whole data life-cycle, and what actually is appropriate? How do we ensure end-to-end reproducibility and where do we draw the practical limits to it? What approach towards licensing should we take for which products and services, and what are the legal / downstream implications? How do we best use identifiers and which ones actually serve the intended purpose? And finally, how do we ensure that effort is rewarded, that best practices are followed, and that misbehavior is identified and potentially sanctioned?

In this contribution we present how the community organization behind EPOS Seismology is discussing these issues, what approaches towards addressing them are being considered, and where we today see the major hurdles on the way towards a truly fair FAIR and Open environment.
Speleothem water content as a proxy for past moisture variability in stalagmites from Milandre Cave, Switzerland
Authors: Affolter Stéphane , Fleitmann Dominik , Häuselmann Anamaria , Leuenberger Markus
Published: March 2020

Speleothems are powerful archives able to gain relevant paleoclimate information on temperature, moisture source or rainfall. Specifically, there is a need for new proxy related to past moisture availability, which would allow reconstruction especially in Europe, where such records are lacking. Among speleothem-based records, quantitative estimation of the water content (hereafter WC) remains rare as it is generally a collateral result of more challenging analyses such as isotope determinations of fluid inclusions or noble gases. Using a recently developed method to analyse speleothem fluid inclusion water isotopes (Affolter et al., 2014), we obtained a record of more than 250 WC data covering the Younger Dryas and Holocene intervals with a decadal to multi-decadal resolution measured on two Swiss stalagmites from Milandre Cave, NW Switzerland. The crushing of samples in the measuring line resulted in a mean WC of 1.9 microlitre of water per gram of crushed calcite from both stalagmites. The comparison with other paleohumidity-related indicators from central Europe suggests that the WC is related to past moisture variability. In addition, trace elements strontium (Sr) and magnesium (Mg) measurements as proxies for the water residence time and growth rate respectively are ongoing at the Department of Environmental Sciences at the University of Basel, which will further help with the interpretation of the WC. New reconstruction of past moisture variability together with speleothem fluid inclusion temperature estimates (Affolter et al., 2019) would allow a better understanding of the central European climate variability during the Holocene.

Affolter, S., Häuselmann, A., Fleitmann, D., Edwards, R. L., Cheng, H., and Leuenberger, M.: Central Europe temperature constrained by speleothem fluid inclusion water isotopes over the past 14,000 years, Sci Adv, 5, eaav3809, 10.1126/sciadv.aav3809, 2019.

Affolter, S., Fleitmann, D., and Leuenberger, M.: New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS), Clim Past, 10, 1291-1304, DOI 10.5194/cp-10-1291-2014, 2014.
Sensitivity of climate mitigation signals to climate engineering choice and implementation
Authors: Turner Katherine , Williams Richard G. , Katavouta Anna , Beerling David J.
Published: March 2020

Unlike historical carbon emissions, which have been driven by economics and politics, climate engineering methods must be scientifically assessed, with consideration as to the type, rate, and total amount implemented. Temperatures reductions from carbon dioxide removal have been found to be proportional to the cumulative amount of carbon removed.  Climate engineering “co-benefits”, such as reduced ocean acidification, may also occur and should be considered when optimising an engineered climate solution. In this study we examine the sensitivities of climate engineering to its implementation, focussing on the effects of its time of onset and rate of carbon capture or enhanced weathering, as well as  background emissions and ocean physics.

We use two simple coupled models– a Gnanadesikan-style coupled atmosphere-ocean model and the intermediate-complexity Earth system model GENIE – with idealised setups for negative emissions through either carbon capture and sequestration, enhanced weathering, or a combination. The inclusion of enhanced weathering provides insight as to how changes in ocean carbonate chemistry may impact climate, both in terms of temperature and pH changes. We have created ensembles in which the timing, rate, background emissions scenario, and model physics of the model vary and use these ensembles to understand how these decisions may impact the efficacy of climate engineering.

We find that the effectiveness of climate engineering is dependent upon the background carbon emissions and the choice of climate engineering. Carbon capture reduces surface average temperature more per PgC captured than enhanced weathering, and both are more effective under low emissions scenarios. Additionally, background emissions determine how the impact of climate engineering is realised: under high emissions, earlier implementation of climate engineering results in faster temperature mitigation, although the end state is independent of the onset. When considering reductions in ocean acidification, we find that the alkalinity flux in our enhanced weathering experiments leads to a higher pH than for carbon capture, as well as the pH signals being less dependent on the timing. Thus, the timing and pathway of the climate engineering is important in terms of the resulting averted warming and acidification, though the final equilibrium is still effectively determined by the cumulative carbon budget.
High-precision cavity ring-down measurements of ẟ13CO2 and 13CH4 along the Eastern North Atlantic onboard the sailing research vessel Fleur de Passion
Authors: Hofmann Magdalena E. G. , Donis Daphne , Bent Jonathan D. , Lucic Gregor , Cesar Ordonez , McGinnis Daniel F.
Published: March 2020

Differentiating microbial, anthropogenic, and thermogenic sources of carbon dioxide (CO2) and methane (CH4) in background air is an important element of understanding upper ocean ecosystem processes. Concentrations of these gases alone are not dispositive indicators of processes, so additional diagnostic parameters including meteorological data, related gas species measurements, and isotopic values can allow researchers to better investigate processes. Here we present data from the Fleur de Passion sailing research vessel which traveled from Dakar, Senegal to the Azores, and to Northwest Spain between early April and October of 2019 as part of the larger Ocean Mapping Expedition by the Geneva-based NPO Fondation Pacifique. The 33-meter-long ketch research vessel carried as part of its instrument suite a Picarro G2201-i high precision gas analyzer, measuring concentrations and ẟ13C values of CO2 and CH4. The high precision data collected by the isotopic carbon analyzer (which are being sampled as part of the University of Geneva’s Winds of Change program) allow for subtle differentiation of modalities separated by a per mil or less, signals that could be lost by infrequent flask measurements or low-precision analyzers. We present findings from this expedition, as well as a brief description of future efforts to measure underway dissolved gases.
Observed and simulated (CMIP5 and CMIP6) early- to late-winter evolution of North Atlantic atmospheric variability and links to the ocean
Authors: Bracegirdle Thomas
Published: March 2020

Research to date has shown strong multi-decadal variability of the North Atlantic Oscillation (NAO) in late winter, particularly in March when correlations to North Atlantic (NA) ocean variability (Atlantic multi-decadal variability (AMV)) are particularly strong. This late-winter low-frequency atmospheric variability appears too weak in the majority of climate models across a range of indices of North Atlantic large-scale atmospheric circulation. It appears that models do not successfully reproduce responses to either (or both) proximal sea-surface temperature (SST) variability at mid-latitudes or teleconnections to SST variability in the sub tropics. 

Here, an in-depth analysis of the winter evolution of multiple indices of North Atlantic mid-latitude atmospheric circulation will be presented based on both re-analysis data and historical simulations of coupled climate models (CMIP5 and CMIP6). The atmospheric indices assessed will include the NAO, speed and latitude of the NA eddy driven jet and lower-tropospheric westerly wind strength in a region of maximum variability to the west of the UK. Results so far indicate that the CMIP6 models do not exhibit a clear change from CMIP5 in terms of the representation of low-frequency late-winter atmospheric variability. To diagnose in more detail possible origins of differences between observed and simulated variability, a detailed evaluation of early- to late-winter evolution in variability of the above indices will be presented, with an initial focus on observations (re-analysis and SST re-constructions) and incorporating the following questions:  
- Are there significant differences in the relative strength of linkages to tropical and extra-tropical SST variability across the different atmospheric indices? 
- Is the observed late-winter maximum in correlations between NA atmospheric indices and North Atlantic SSTs still apparent at sub-decadal timescales?
Initial results indicate that there are stronger tropical linkages for jet speed and that at sub-decadal timescales late winter is does not dominate in terms of correlations between atmospheric and SST variability. Updates on these early results will be presented along with implications of the results for differences between observed and simulated variability. 