bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding our capabilities in observing and modelling Coronal Mass Ejections
Authors: Verbeke Christine , Mierla Marilena , Mays M. Leila , Kay Christina , Dumbovic Mateja , Temmer Manuela , Palmerio Erika , Paouris Evangelos , Cremades Hebe , Riley Pete , Scolini Camilla , Hinterreiter Juergen
Published: March 2020

Coronal Mass Ejections (CMEs) are large-scale eruptions of plasma and magnetic fields from the Sun. They are considered to be the main drivers of strong space weather events at Earth. Multiple models have been developed over the past decades to be able to predict the propagation of CMEs and their arrival time at Earth. Such models require input from observations, which can be used to fit the CME to an appropriate structure.

When determining input parameters for CME propagation models, it is common procedure to derive kinematic parameters from remote-sensing data. The resulting parameters can be used as inputs for the CME propagation models to obtain an arrival prediction time of the CME f.e. at Earth. However, when fitting the CME structure to obtain the needed parameters for simulations, different geometric structures and also different parts of the CME structure can be fitted. These aspects, together with the fact that 3D reconstructions strongly depend on the subjectivity and judgement of the scientist performing them, may lead to uncertainties in the fitted parameters. Up to now, no large study has tried to map these uncertainties and to evaluate how they affect the modelling of CMEs.  

Fitting a large set of CMEs within a selected period of time, we aim to investigate the uncertainties in the CME fittings in detail. Each event is fitted multiple times by different scientists. We discuss statistics on uncertainties of the fittings. We also present some first results of the impact of these uncertainties on CME propagation modelling.

Acknowledgements: This work has been partly supported by the International Space Science Institute (ISSI) in the framework of International Team 480 entitled: Understanding Our Capabilities In Observing And Modelling Coronal Mass Ejections'.
A modified index to evaluate the sediment connectivity at the catchment scale in Mediterranean torrents
Authors: Bombino Giuseppe , Boix-Fayos Carolina , Carrà Bruno Gianmarco , Cataldo Maria Francesca , D'Agostino Daniela , Denisi Pietro , De Vente Joris , Labate Antonino , Nucera Antonella , Zema Demetrio Antonio
Published: March 2020

In Mediterranean environments, where soil erosion rates are often not tolerable, sediment connectivity at the watershed scale needs accurate evaluation tools. Quiñonero-Rubio et al. (2013) proposed the Catchment Connectivity Index (CCI) to describe hydrological and geomorphological factors. It requires the combination of considerable skills to data sources and demanding field surveys. In order to improve the index and to simplify its application, in this study we propose a modified version of the CCI, the mCCI, that produces a more efficient description of the hydrological and geomorphological parameters composing CCI and, thanks to the large use of GIS software, making easier its applicability for operators with less field experience.

The mCCI is applied in a torrent of Calabria (Southern Italy) to evaluate the sediment connectivity at the catchment scale, by comparing four scenarios: a combination of check dam presence or not and land use or not, in 1955 and in 2012. This case study has shown how and by what extent the natural and human impacts (climate and land-use changes and check dam installation) have affected the geomorphic processes influencing sediment circulation in the studied basin throughout six decades. From 1955 to 2012, a general decrease in sediment connectivity has been caught by the mCCI, as a result of the combined effects of greening-up processes of the catchment (due to both natural afforestation and human-induced reforestation) and the installation of check dams, which have decreased the catchment potential to circulating sediments. Overall, the mCCI can be used as an analytical tool to evaluate the influence of past or future changes in natural and human-induced changes in land use and climate actions to give support to land planners in watershed management tasks.
Modeling ocean eddies and their effects on ice shelf basal melt rate in the Ross Sea
Authors: Mack Stefanie , Dinniman Mike , Klinck John , McGillicuddy, Jr. Dennis , Padman Laurie
Published: March 2020

Ice shelf basal melt rates around Antarctica are affected by the advection of warm Circumpolar Deep Water (CDW) onto the continental shelf and under the ice shelf. In ocean models, resolving mesoscale eddies is necessary to capture eddy fluxes of CDW and estimate basal melt rates of ice shelves. Where and when (not if) eddies are resolved in an ocean model depends on the baroclinic Rossby radius and thus on stratification and latitude. The Ross Sea presents some interesting scientific questions in two regards: first, it is weakly stratified in winter conditions, lowering the radius of deformation; and second, the Ross Ice Shelf melts mainly from dense shelf water at the grounding line and from light surface water at the ice shelf front, rather than CDW. An investigation using a ROMS (Regional Ocean Modelling System) model of the Ross Sea reveals that portions of the domain (48% in well-mixed winter conditions, and 33% in stratified summer conditions) do not resolve mesoscale eddies even at a horizontal grid spacing of 1.5 km. We find that smaller grid spacing (1.5 km versus 5 km) leads to increased eddy generation in the model, and eddies that cross the ice shelf front in both directions. However, there is no significant change in basal melt between low and high resolution simulations. While even higher resolution is needed to fully represent eddies in the Ross Sea, the processes that control basal melt of the Ross Ice Shelf may not be strongly affected by these eddies.
The Earth’s Correlation Wavefield: Proof of Concept, Origin and Applications
Authors: Tkalčić Hrvoje , Wang Sheng , Pham Thanh Son
Published: March 2020

We have recently shown that all features in the earthquake-coda correlogram can be explained by the similarity of seismic phases that have a common slowness for the analysed receiver pair. This includes both the features that have their equivalents in the conventional traveltime stacks, but also those that were previously unexplained. Consequently, the information contained in the correlograms – cross-correlated ground-motion time-series in a two-dimensional representation – can be used to constrain Earth’s internal structure, however, that requires a proof of concept and further investigation into the origin of the correlation wavefield. We thus first decompose relevant correlogram features into discrete constituents with respect to their arrival times and we uniquely identify contributing seismic phases to each constituent. This confirms that the correlation wavefield does not arise due to the reconstruction of body waves between the two receivers (a.k.a. Green’s function) – instead, it is dominated by the interaction of various body waves, and its features are characterised by complex sensitivity kernels.

We demonstrate that the event locations relative to the receivers alter the similarities between the body waves, and may result in significant waveform distortions and inaccuracies in arrival-time predictions. We further show that the nature of source-mechanism and energy-release dynamics are the key influencers responsible for individual correlograms equal in quality to a stack of hundreds of correlograms. In other words, a single seismic event that meets a set of criteria in the presence of multiple receivers can completely `illuminate’ the Earth’s interior. Quantitative kernel-decomposition and identification of body-wave pairs that contribute to a given feature in the correlogram, along with informed choices of seismic events, thus makes the correlation-wavefield tomography and other applications fully feasible. This has the potential to change the course of global seismology in the coming decades.
Competitive divalent cation incorporation in the ferrous phosphate mineral vivianite
Authors: Kubeneck L. Joëlle , ThomasArrigo Laurel K. , Rothwell Katherine A. , Kretzschmar Ruben
Published: March 2020

Phosphorus (P) is often a limiting nutrient in soils and aquatic systems, but excessive concentrations can lead to eutrophication. The chemical forms in which P is retained in soils and sediments determine its bioavailability. Under reducing conditions, the ferrous phosphate mineral vivianite has been shown to be a major P burial phase in various environments such as coastal sediments. Depending on the local environmental geochemistry, ferrous iron (Fe2+) can be substituted by other divalent cations such as magnesium (Mg2+) and manganese (Mn2+). The substitution of Fe2+ could alter mineralogical characteristics of vivianite, which influences its further reactivity and thus the P and iron (Fe) cycle. Despite the importance of divalent cation substitution in vivianite in the environment, questions remain if certain divalent cations are preferentially incorporated and how they compete for substitution.

Here, we assessed the competitive incorporation of Mn2+ and Mg2+ into vivianite by carrying out vivianite precipitation experiments in anoxic aqueous solutions at pH 7. Additionally, we explored how varying salinity simulating an estuarine gradient influences the incorporation of Mn2+ and Mg2+. Changes in mineralogy with different degrees of Mn2+/ Mg2+ substitution were studied with X-ray powder diffraction, Raman spectroscopy, total elemental dissolution and other techniques.

Based on 19 different vivianites, our results demonstrate that Fe2+ is replaced by up to 50% by Mn2+/ Mg2+ in the vivianite structure, with preferential incorporation of Mn2+ over Mg2+. Increases in salinity seem to slightly enhance divalent cation incorporation. Following from our results, we will discuss the factors influencing divalent cation incorporation into vivianite, and how divalent cation substitution alters mineralogical characteristics. Finally, we will highlight how the substitution of Fe2+ by other divalent cations potentially enhances P fixation in form of vivianite under Fe-limiting conditions.
Correlative cathodoluminescence and EDS imaging of the benthic agglutinated foraminifer Liebusella goesi
Authors: Hari Sangeetha , Littmann Sten , Glock Nicolaas , von Arx Jan , Coenen Toon , Roy Alexandra-Sophie
Published: March 2020

Sedimentary rocks, formed by the accumulation of mineral and organic particles, are important both for studies of the earth’s history as well as for being a source of fossil fuels. Over the course of the last decades, it has been demonstrated that scanning electron microscope (SEM)-based cathodoluminescence (CL) spectros­copy is a valuable technique for the characterisation of sedimentary rocks, complementary to other electron microscopy-based techniques, such as backscattered electron imaging (BSE/EBSD) and energy dispersive x-ray spectroscopy (EDS). Typically the CL yield is high enough for rapid scanning and, in some cases, even video-rate scanning, allowing fast in­spection of relatively large areas. It can be used to quantitatively map the quartz composition of the sample, for example, which enables the rigorous segmentation of granular and cemented material.

Textulariid benthic foraminifers live on and in seafloor sediments and form shells of agglutinated sediment particles. They are very important biostratigraphic markers, and fossil agglutinated foraminifera are important archives for paleoceanographic reconstructions. Furthermore, living textulariids show a strong diversity, populating  a diverse range of marine habitats partly and can reach high living abundances, making them important for benthic ecosystems.

In this work, we show how CL spectroscopy can be employed to study agglutinated foraminifera using the species Liebusella goesi from the Swedish Gullmar Fjord as an example. Fast panchromatic imaging using a photomultiplier tube was performed over a large area of the foraminifera, which revealed textures and contrasts of interest in the shell (test). A high resolution SEM image was acquired simultaneously to provide spatial context. Such a dataset can be valuable in establishing the geological history as well as in identifying the chemical composition of the cement used for the agglutination of sediment particles. Both the composition of the agglutinated particles and the chemical composition of the cement might bear valuable information about the environmental conditions, when the test was formed. EDS measurements were performed, revealing the spatial distribution of elements such as potassium, calcium, sodium, silicon and oxygen, in the sediment particles of the shell. This was useful in indicating the presence of minerals such as quartz and feldspar, and hyperspectral CL imaging was performed to rigorously identify them, and to visualize intragranular features, not visible in the EDS data. Based on the CL spectral data, we were further able to identify different grades/types of quartz and feldspars. These results show that these foraminifera prefer different sediment materials with varying grain sizes, depending on the size of the newly formed chamber, to achieve the highest mechanical stability.
Vertical distribution of aerosols in dust storms during the Arctic winter
Authors: Dagsson Waldhauserova Pavla , Renard Jean-Baptiste , Olafsson Haraldur , Vignelles Damien , Berthet Gwenaël , Verdier Nicolas , Duverger Vincent
Published: March 2020

High Latitude Dust (HLD) contributes 5% to the global dust budget, but HLD measurements are sparse. Iceland has the largest area of volcaniclastic sandy desert on Earth where dust is originating from volcanic, but also glaciogenic sediments. Total Icelandic desert areas cover 44,000 km2 which makes Iceland the largest Arctic as well as European desert. Icelandic volcanic dust can be transported distances > 1700 km towards the Arctic and deposited on snow, ice and sea ice. It is estimated that about 7% of Icelandic dust can reach the high Arctic (N>80°). It is known that about 50% of Icelandic dust storms occurred during winter or subzero temperatures in the southern part of Iceland. The vertical distributions of dust aerosol in high atmospheric profiles during these winter storms and long-range transport of dust during polar vortex condition were unknown.

Dust observations from Iceland provide dust aerosol distributions during the Arctic winter for the first time, profiling dust storms as well as clean air conditions. Five winter dust storms were captured during harsh conditions.  Mean number concentrations during the non-dust flights were < 5 particles cm-3 for the particles 0.2-100 µm in diameter and > 40 particles cm-3 during dust storms. A moderate dust storm with > 250 particles cm-3 (2 km altitude) was captured on 10th January 2016 as a result of sediments suspended from glacial outburst flood Skaftahlaup in 2015. Similar particle number concentrations were reported previously in the Saharan air layer. Detected particle sizes were up to 20 µm close to the surface, up to 10 µm at 900 m altitude, up to 5 µm at 5 km altitude, and submicron at altitudes > 6 km.

Dust sources in the Arctic are active during the winter and produce large amounts of particulate matter dispersed over long distances and high altitudes. HLD contributes to Arctic air pollution and has the potential to influence ice nucleation in mixed-phase clouds and Arctic amplification.

 

Reference:

Dagsson-Waldhauserova, P., Renard, J.-B., Olafsson, H., Vignelles, D., Berthet, G., Verdier, N., Duverger, V., 2019. Vertical distribution of aerosols in dust storms during the Arctic winter. Scientific Reports 6, 1-11.
Sentinel-4 Instrument Data Simulator
Authors: Hao Nan , Gimeno Garcia Sebastian
Published: March 2020

The Sentinel-4 (S4) mission, the first imaging spectrometer instrument to be flown on Meteosat Third Generation Sounding (MTG-S) satellite in geostationary orbit, will provide accurate data on an hourly basis of trace gases and aerosols over Europe and Northern Africa for climate, air quality, ozone and surface UV applications. It features bands in the ultraviolet (305-400 nm), and visible (400-500 nm) with a spectral resolution of 0.5 nm and in the near-infrared (750-775 nm) ranges with a spectral resolution of 0.12 nm.

To provide simulated S4-UVN instrument data, we are working to prepare the Instrument Data Simulator (IDS). IDS is supposed to provide test data for the L1b Processor and provide capability for instrument performance and calibration monitoring. The IDS consists of two main blocks: the Scene Generator (SG) simulates the radiance/irradiance at the entrance of the instrument and the Instrument Simulator (IS) simulates the response of the instrument on the input signal. The S4-UVN IS follows as much as possible the instrument forward model and will be developed using a ’travelling spectrum’ approach. In this approach, the flux in the instrument or signal and noise is modified step-by-step by a series of algorithms representing the effects of the different components of the instrument on signal when flowing through the instrument. The IDS architecture, instrument forward model and the preliminary output of IDS will be introduced.
Aeolian inputs as parent materials for Podzols and terra-rossa soils in a dolomitic landscape in the Italian Alps (Salmezza, BG, Italy)
Authors: D'Amico Michele , Casati Enrico , Barcella Marco , Previtali Franco
Published: March 2020

On an unglaciated karst landscape in the Lombard Pre-Alps (Salmezza, Bergamo, Italy), an extremely high pedodiversity occurs across a few hectares on Norian dolostone. The rock is locally enriched in well crystallized sand-grained quartz. The climate of the area is suboceanic, with >1500 mm of annual rainfall, and an average temperature around 6-8°C. Rendzic Leptosols and Phaeozems are developed on the steepest slopes, Podzols, Cambisols and Luvisols on flatter areas, while Rhodic Luvisols/Alisols (Terra-Rossa soils) are found in doline cracks and crevices. The sand-grained quartz content of the parent rock seems to be the main soil differentiating factor: where it is abundant (ca. 10-20% in volume), it is responsible for the genesis of Podzols.

We sampled and analyzed 9 soil profiles from the Salmezza area, thus characterizing all pedogenic processes active in the area. In particular, we analyzed standard soil chemical properties (pH, organic carbon, base status and Cation Exchange Capacity, dithionite and oxalate-extractable Fe and Al); we performed a total elemental analysis on most samples and on substrate samples, in order to calculate mass balance and element loss and enrichment; we observed thin sections and performed XRD analysis in powder samples and on the clay fraction of most pedogenic horizons as well.

The parent material is a rather pure dolostone, composed of dolomite, locally enriched in quartz. No other minerals have been observed. Very little amounts of Fe, Al and other elements are thus included in the parent rock (almost completely composed of Ca, Mg and Si), often very close to the analytical detection limit. Ca and Mg were almost completely lost during most soil forming processes in this temperate humid climate, while the enrichment in Si, Fe, Al varies broadly amidst the different soils, thanks to different pedogenic processes. Fe and Al, in particular, were up to 120 times more concentrated in Bt and Bhs horizons than in the parent rock. The ratios between stable elements in rocks and soils verifies important inputs of aeolian materials. The values are, however, different also amidst different soils, so an univocal origin of aeolian materials cannot be hypothesized. The mineralogy of the clay fraction is also strongly modified by pedogenesis, so that each soil type is characterized by a different mineralogical assemblage, making it difficult to detect signatures of specific aeolian origins as well.
The application of airborne remote sensing during an On-Site Inspection
Authors: Rowlands Aled , Labak Peter , Chiappini Massimo , Gaya-Pique Luis , Buckle John , Seywerd Henry
Published: March 2020

The application of airborne remote sensing techniques permitted by the Comprehensive Nuclear‑Test‑Ban Treaty (magnetic and gamma survey as well as optical imaging including infrared measurements) is done through the prism of inspection team functionality – a logic which applies equally to air and ground-based techniques. Work undertaken over recent years through modelling and practical testing has aimed to better understand the ability of airborne remote sensing techniques to detect relevant observables under different conditions. This has led to the compilation of a concept of operations document that provides guidance on the application of inspection activities during an On-Site Inspection. As well as highlighting the relative merits of each technique, the document also addresses the relative likelihood a particular airborne technique will return relevant information and will avoid the commitment of resources to missions with little likelihood of success.

The paper also addresses the approaches which have been taken to streamline the acquisition of airborne remotely sensed data through bespoke installations, the identification of optimal data processing routines to facilitate the production of reports and the fusion of airborne data products with other data gathered during an inspection.
40-years of Saharan dust events in the Carpathian Basin: background, frequency, intensity, changing patterns
Authors: Varga György , Gammoudi Nadia , Kovács János
Published: March 2020

Saharan dust events were investigated in the Carpathian Basin (Central Europe) for the period between 1979 and 2018 by using various satellite (TOMS and OMI Aerosol Index; MODIS AOD) and numerical forecast (Barcelona Supercomputing Centre’s DREAM, NMMB/BSC-Dust-model and SKIRON) products and modelled deposition of NASA’s Modern-Era Retrospective analysis for Research and Applications, Version 2. The identified 218 episodes were classified into three characteristic clusters based on synoptic background. 700 hPa geopotential height, wind vectors and meridional flow patterns, as well as backward trajectories of the episodes determined the classification.

Interannual variability of dust activity was remarkable, while seasonal frequencies of the episodes revealed clear spatiotemporal patterns with spring (40.2%) and summer (31.6%) maxima of the events. Mean values of dust deposition showed springtime maxima (44.1%) and dominance of wet deposition (77-93%), while amount of deposited dust material in the other seasons were quite similar, indicating the governing role of local weather conditions (e.g., precipitation patterns). Average warm advection of the episodes was 3.5°C (with spring minima, due to the more rain), but the decadal surface air temperature anomalies showed a general increasing trend.

Recently, a few more intense wintertime dust deposition events indicated changes in the deterministic atmospheric flow system. Seasonal and decadal zonal mean surface air temperature anomalies of dusty days showed clearly the increased warming of high latitudes during the last few winter episodes. The enhanced meridionality of (dust transporting) winds was also observable in the number of days with 15< m/s meridional wind component (at 700 hPa). Warmer Arctic region and more meandering air flow patterns could be responsible for these unusual dust episodes in the recent years.

Support of the National Research, Development and Innovation Office NKFIH KH130337 and NKFIH K120213 are gratefully acknowledged.
Contrasting style and retreat rates of the northern hemisphere ice sheets during the past two glacial terminations
Authors: Gasson Edward , Stoll Heather , Cacho Isabel
Published: March 2020

Compared with the intensely studied interval of the last glacial maximum and termination, significantly less attention has been given to the preceding glacial period and Termination 2. This is perhaps understandable as the Greenland ice cores do not stretch this far back in time and the terrestrial record of the ice sheets has in part been lost during the subsequent glacial period. However, there are many questions remaining about how these two glacial intervals differed and whether this was important in driving some of the differences between the last interglacial and our current interglacial. Here I will focus on a new speleothem record from northern Spain which records the meltwater-driven d18O anomaly in the eastern North Atlantic and provides an absolutely dated chronology (U/Th) during the penultimate glacial and Termination 2. The character of which differs dramatically from a record for Termination 1 recovered from speleothems at the same site. This record also shows structure during Termination 2 that has not been seen previously. Here I’ll discuss some possible reasons for the differences between the two glacial terminations and focus on recent ice sheet model experiments that have been run to try and test these hypotheses.

 
MAIDENiso: a mechanistic approach to the reconstruction of past climate from tree chronologies
Authors: Boucher Etienne , Hermoso de Mendoza Ignacio , Gennaretti Fabio
Published: March 2020

The ecophysiological forest model MAIDENiso (Modeling and Analysis In + isotopes) uses a set of mechanistic rules to simulate the production, allocation and growth of virtual trees. MAIDENiso is adapted to the boreal tree species Picea mariana Mill. (Black spruce), but lacks a hydrological module adapted for boreal meteorological conditions. With the recent addition of a snow/ice module, MAIDENiso is now capable of realistically simulating snow cover and discharge in high latitude regions, while at the same time capturing climate-sensitive processes such as the enrichment of heavy water isotopes due to snow sublimation. The more realistic outputs of the model can be compared to tree ring records (ring widths and stable isotopes). This allows us to use an inversion algorithm (based on a Metropolis Hastings random walk) to estimate past hydroclimate conditions that are in line with physiological and hydrological processes of high boreal regions. We apply this methodology to a millennial chronology of tree ring width and cellulose isotopes from sub-fossil tree remains in North-Quebec, and produce an updated hydroclimate reconstruction of the last 1000 years in this region.

 
Studying Fluvial Tipping Points with Remotely Sensed Observations and Hydroclimatic Data in the Selenga River Delta
Authors: Aminjafari Saeid , Brown Ian , Jarsjö Jerker , R. Chalov Sergey , Jaramillo Fernando
Published: March 2020

Lake Baikal, located in eastern Russia, is the oldest (25 million years) and the deepest (~1800 meters) lake in the world. There are many rivers flowing into the Lake Baikal (~ 365 rivers), of which the Selenga River is the most important one being responsible for almost 55% of the runoff water into the system and also 60% of the transported sediments. As the hydrological changes of the river and its delta enormously alter the neighbouring area, it is of utmost importance to explore the dynamics of change in terms of flow magnitude, paths and fluvial geomorphology, and the related tipping points defining different states. The questions this study aims to answer are: What are the fluvial geomorphological and hydrological changes? What fluvial geomorphological tipping points can be identified during the last 34 years and what are the discharge and climatic conditions that induce them? In this study, we use the Global Surface Water Dataset (GSWD) to analyze the changes in the river’s stream network. With these products, we assess changes in several fluvial geomorphological proxies (e.g., sinuosity, fractal dimension, meandering characteristics, planform information) and identify possible tipping points. We relate these changes to different hydrological and climatic conditions such as precipitation, river discharge and Lake Baikal water level. We find evident changes in the meandering behaviour and flow path of the Selenga River tributaries in the Delta. The number of oxbow lakes based and corresponding size distribution has varied in time, and evident flow path changes occur that seem to be related to flooding periods, and there appears to be a consistent relationship between meandering and the river discharge variability. These results enable policymakers to understand different contributing factors altering the Selenga River Delta and ultimately leading to better decisions to manage the effects of these changes in the area.
The effect of stream microbial inoculation on in-stream carbon processing
Authors: Schelker Jakob , Caillon Florian , Besemer Katharina , Peduzzi Peter , Harjung Astrid
Published: March 2020

Hydrological events mobilize chemically diverse dissolved organic matter (DOM) from soils to streams. Further, such events can also cause an influx of soil microbial life into fluvial systems. Here we present results from the HYDRO-DIVERSITY project, which aims to investigate the dynamic transfer of DOM and microbial life from catchment soils to streams, as well as their downstream fate. We studied the microbial community composition and DOM quality using 16S Illumina sequencing and fluorescence and absorbance spectroscopy. Data from small streams showed strong changes in DOM composition and in the microbial community delivered from soils during hydrological events. Moreover, we performed a flume experiment, in which soil microbial inoculation and the processing of DOM across different biofilm ages were evaluated. As such, biofilm age did not directly affect the establishment of soil microbes in the stream ecosystem. However, in-stream processing of soil DOM appeared to be affected by the inoculation event. This poses the fundamental question, if the processing of DOM in streams and rivers depends on the transient presence of specific soil microbes in stream ecosystems. Overall our results show that soils provide a dynamic and relevant influx of microbes and DOM to first order streams and that this dynamic influx likely affects microbial community dynamics of downstream fluvial networks as well as in-stream DOM processing. 
Climate change impacts on European wheat and maize yields
Authors: Toreti Andrea , Ceglar Andrej , Dentener Frank , Fumagalli Davide , Bassu Simona , Cerrani Iacopo , Niemeyer Stefan , Bratu Marian , Panarello Lorenzo
Published: March 2020

Crop yields are influenced and affected by climate conditions and the occurrence of extreme events in critical phenological phases during the growing season. As projected climate change for Europe points to an increase of climate extremes as well as a significant warming together with changes in precipitation regimes, it is essential to assess impacts on key socio-economic sectors such as agriculture. Here, we analyse European wheat and maize yields as projected by a crop model driven by bias-adjusted Euro-CORDEX regional climate model simulations under the RCP4.5 and RCP8.5 scenarios. The main findings highlight as maize will be the most affected crop with limited effects of simple adaptation strategies; while a north-south dipole in the projected changes characterizes wheat yields. In the wheat regions negatively affected by climate change, adaptation strategies will play a key role in counterbalancing the impacts of the projected changes. 
Data visualisation and information design at the science-policy interface: drawing from the IPCC experience.
Authors: Melissa Gomis , Sophie Berger , Robin Matthews , Sarah Connors , Ozge Yelekci , Jordan Harold , Angela Morelli , Tom Gabriel Johansen
Published: March 2020

In this digital age, communication has become increasingly visual. Like never before, visual information is increasing exposure and widening outreach to new audiences. With growing demands from Journals (Table of Content arts, visual abstracts, scientific figures), conferences (posters, presentation) and competitive grants submissions, the science world is not spared, and figures represent a tremendous opportunity to communicate findings more effectively. It is therefore important to get figures and images right for the intended audience, even more so when visualizing scientific data and conveying complex concepts. 

The Intergovernmental Panel on Climate Change (IPCC), whose primary role is to inform policy makers on the state of knowledge on climate change, showcases how complex science can be visually communicated to a non-expert audience. Since its fifth assessment report, published in 2014, the IPCC has acknowledged the importance of communicating its assessments in an understandable, accessible, actionable and relevant way to all its stakeholders without compromising on the scientific robustness and accuracy. 

Currently in its sixth assessment cycle, the IPCC features a new approach to figure design in its three recently published Special Reports. This approach consists in an unprecedented collaboration between design, information and cognitive specialists and the IPCC authors. This co-design process, along with a continuous guidance to authors on visualization and cognitive concepts, was conducted in a user-centered way to best serve the audience needs and their respective background. The challenge of visually representing multi-disciplinary results, testing, evaluating, and refining the figures improved the clarity of the key messages. The entire co-design method has proven to be a successful process during the preparation of the special reports and the preparation of the sixth assessment report is building on this experience. Despite a lack of available analytics, the IPCC communication department has observed an unprecedented media coverage and a certain amount of derivative products based on the special reports figures created by third parties.
On the use of Geostationary Lightning Mapper data as proxy for heavy precipitation
Authors: Bourscheidt Vandoir , Ramos Maria-Helena
Published: March 2020

In view of the likely increase of thunderstorm and extreme precipitation events under climate change scenarios, alternatives to improve the estimates of rainfall and the understanding of the runoff response to extreme events are relevant, especially in areas with low or absent radar or raingauge coverage. Efforts in this direction have resulted, for example, on the Global Precipitation Measurement (GPM) products, which offer potentially useful estimates of precipitation over relatively fine spatial and temporal scales. With the launch of GOES 16 satellite, with its new Geostationary Lightning Mapper (GLM) instrument and improved visible and infrared imagery (with the Advanced Baseline Imager - ABI), new possibilities emerge in the analysis of (severe) convective precipitation and its impact on runoff. In this work, we analyze the relationship between lightning activity and rainfall, with the aim to estimate how total lightning data can be used as proxy of (heavy) precipitation estimates. GLM data is evaluated against weather radar in three different ways: (1) based on a Gaussian Kernel method; (2) using a simple dot-count approach, and (3) using the operational GLM gridded product, built on the ABI fixed grid (2 x 2 km). Two sample strategies are evaluated: a pixel-based comparison and a comparison method that extracts statistics inside polygons (using watersheds). For all cases, both group and flash data from GLM are used. The study area focuses on the southeastern and central-west regions of Brazil, where developments towards enhanced flood nowcasting and warning systems capabilities have been carried out in order to anticipate flash floods and prevent flood damages in the future.
The Italian TREETALKER NETWORK (ITT-Net): continuous large scale monitoring of tree functional traits and vulnerabilities to climate change
Authors: Castaldi Simona , Antonucci Serena , Asgharina Shahla , Battipaglia Giovanna , Belelli Marchesini Luca , Cavagna Mauro , Chini Isaac , Cocozza Claudia , Gianelle Damiano , La Mantia Tommaso , Motisi Antonio , Niccoli Francesco , Pacheco Solana Arturo , Sala Giovanna , Santopuoli Giovanni , Tonon Giustino , Tognetti Roberto , Zampedri Roberto , Zorzi Ilaria , Valentini Riccardo
Published: March 2020

The  Italian TREETALKER NETWORK (ITT-Net) aims to respond to one of the grand societal challenges: the impact of climate changes on forests ecosystem services and forest dieback. The comprehension of the link between these phenomena requires to complement the most classical approaches with a new monitoring paradigm based on large scale, single tree, high frequency and long-term monitoring tree physiology, which, at present, is limited by the still elevated costs of multi-sensor devices, their energy demand and maintenance not always suitable for monitoring in remote areas. The ITT-Net network will be a unique and unprecedented worldwide example of real time, large scale, high frequency and long-term monitoring of tree physiological parameters. By spring 2020, as part of a national funded project (PRIN) the network will have set 37 sites from the north-east Alps to Sicily where a new low cost, multisensor technology “the TreeTalker®” equipped to measure tree radial growth, sap flow, transmitted light spectral components related to foliage dieback and physiology and plant stability (developed by Nature 4.0), will monitor over 600 individual trees. A radio LoRa protocol for data transmission and access to cloud services will allow to transmit in real time high frequency data on the WEB cloud with a unique IoT identifier to a common database where big data analysis will be performed to explore the causal dependency of climate events and environmental disturbances with tree functionality and resilience.

With this new network, we aim to create a new knowledge, introducing a massive data observation and analysis, about the frequency, intensity and dynamical patterns of climate anomalies perturbation on plant physiological response dynamics in order to: 1) characterize the space of “normal or safe tree operation mode” during average climatic conditions; 2) identify the non-linear tree responses beyond the safe operation mode, induced by extreme events, and the tipping points; 3) test the possibility to use a high frequency continuous monitoring system to identify early warning signals of tree stress which might allow to follow tree dynamics under climate change in real time at a resolution and accuracy that cannot always be provided through forest inventories or remote sensing technologies.

To have an overview of the ITT Network you can visit www.globaltreetalker.org

 
Spaceborne monitoring of CO2 emissions from large cities and the impact of aerosols
Authors: Houweling Sander , Landgraf Jochen , Reum Friedemann , van Heck Hein , Tao Wei , Cheng Yafang , Vlemmix Tim , Stammes Piet
Published: March 2020

International agreements to reduce CO2 emissions call for an independent mechanism for evaluating the compliance with emission reduction targets. Atmospheric measurements can provide important information in support of this goal. However, to do this globally requires a drastic expansion of the existing monitoring network, using a combination of surface measurements and satellites. CO2 sensing satellites can deliver the required spatial coverage, filling in the gaps that are difficult to cover on ground. However, to reach the accuracy that is required for monitoring CO2 from space is a challenge, and even more so for anthropogenic CO2.

The European space agency is preparing for the launch of a constellation of satellites for monitoring anthropogenic CO2 within the Copernicus program, starting in 2025. Scientific support studies have been carried out to define this mission in terms of payload and observational requirements. We report on the AeroCarb study, which investigated the impact retrieval errors due to aerosols in CO2 plumes downwind of large cities, and the potential benefit of an onboard aerosol sensor to help mitigate such errors. In this study, CO2 and aerosol plumes have been simulated at high-resolution for the cities of Berlin and Beijing. The impact of aerosol scattering on spaceborne CO2 measurements has been assessed using a combined CO2-aerosol retrieval scheme, with and without the use of an onboard multi-angular spectropolarimeter (MAP) for measuring aerosols. The results have been used to quantify the accuracy at which the CO2 emissions of Berlin and Beijing can be quantified using inverse modelling and the impact of aerosols depending on the chosen satellite payload. 

In this presentation we summarize the outcome of this study, and discuss the implications for the space borne monitoring of anthropogenic CO2 emissions from large cities.
Modelling the response of Mediterranean maize yields to projected climate change
Authors: Bassu Simona , Fumagalli Davide , Toreti Andrea , Ceglar Andrej , Giunta Francesco , Motzo Rosella , Niemeyer Stefan
Published: March 2020

Understanding the effects of different combinations of sowing dates and choice of cultivars on maize yield is essential to develop appropriate climate change adaptation strategies. In this study, we explore the maize yield response of two models to changes in sowing dates and cultivars. In particular, we assess whether crop conditions around flowering can explain the variability of irrigated, potential crop yields across sowing dates and cultivars in Mediterranean climatic conditions where high temperatures may change the length of the grain filling period. Then, we investigate these responses under future climate projected conditions till 2060 by using Euro-CORDEX regional climate model simulations.

Main findings show that the approach based on anthesis conditions outperforms the model based on partitioning. This holds both under current and future climate conditions. Finally, both approaches agree on a warmer climate translating into lower yields (13-18%, average reduction with respect to the current climate conditions) than can only be partially offset by changes in phenology and sowing dates.
Sea ice characteristics during the Weddell Sea expedition explored by geophysical and remote sensing methods
Authors: Rack Wolfgang , Christie Frazer , Dowdeswell Evelyn , Dowdeswell Julian , Wachter Paul , Benham Toby , Haas Christian , Bealing Paul
Published: March 2020

The 2019 Weddell Sea expedition provided a unique opportunity for geophysical and glaciological sea ice measurements in one of the least accessible regions of the Southern Ocean. Although the extent and area of sea ice is well known based on satellite measurements, the limited information on thickness does still hinder the calculation of trends trends in volume and mass. Sea ice thickness is therefore one of the missing key variables in the global cryosphere mass balance, and difficult logistics are a challenge for near synchronous satellite validation measurements. Another key variable in this context is snow on sea ice, as knowledge of snow is required to convert satellite-derived freeboard to thickness.

We measured the sea-ice morphology by a combination of on ice and remote sensing methods: near-synchronous temporal and spatial measurements from a drone equipped with a radar sensor and camera, manually-derived on-ice surveys and samples such as snow pits, snow-depth transects and drill holes, and a AUV with upward-looking multibeam sonars. We also deployed ice-drifter buoys on several ice floes which we used to provide floe drift over an extended period of time.

In this contribution we present the results of our observations in conjunction with a close sequence of high resolution satellite radar images (TerraSAR-X, Sentinel-1) and altimeter data (ICESat-2 and CryoSat-2) to characterise the sea ice conditions in the western Weddell Sea. We found a mixture of fragments of deformed first-year and multi-year sea-ice which was consolidated in larger ice floes. A thick snow cover frequently depressed the ice cover of the thinner first year ice below sea level. Satellite data allow to extend our findings in time to a larger area and to improve our information on sea ice over a larger region.
Lightning Clustering to Study Regional Variations in Thunderstorm Characteristics
Authors: Lapierre Jeff , Stock Michael
Published: March 2020

Many studies have shown that the characteristics of lightning such as size and peak current differ by geographical region as well as between ocean and continental thunderstorms. For example, several studies have shown that the lightning in oceanic thunderstorms are generally larger and have lightning with higher peak currents than in continental thunderstorms. In this study, as opposed to individual lightning flash characteristics, we focus on how thunderstorm characteristics change for various regions. We develop a lightning clustering algorithm that takes individual lightning strokes and creates thunderstorms based on their spatiotemporal proximity. We use lightning data from the Earth Networks Total Lightning Network and compare storms throughout regions of the U.S.A. and Europe. Once these thunderstorms are obtained, we can regionally categorize them and compare various characteristics (size, duration, flash rate, polarity, IC/CG ratio, etc.) to determine if any differences stand out. In this presentation, we will discuss the clustering algorithm used, analyze the results of the study, and discuss implications.
Mobile matter in the aeration zone of the Hainich Critical Zone Exploratory: First results from one-year monitoring by employing novel drain collectors
Authors: Eshvara Arachchige Dinusha , Totsche Kai Uwe
Published: March 2020

Biogeochemical processes in the aeration zone (AZ) may severely affect the fluid flow, composition, and the amount of mobile matter. The AZ is a subsurface part of the Critical Zone (CZ) that connects the soils sensu stricto (SSS) with the aquifers. Depending on the groundwater dynamics, the fluid transiting in the AZ is not only recharged by the ascending seepage, but also by upwelling groundwater. Since the collection of fluids is a rather demanding task, fluid migration and matter transport have not been considered in CZ research so far. To address this research gap, we developed novel drain collectors and installed twenty of them within four different lithologies in the fractured carbonate AZ of the Hainich Critical Zone Exploratory (Hainich CZE) in central Germany. Drainage sampling was done on a regular monthly basis with additional event-based sampling. Size, chemical composition, and physio-chemical properties of the aqueous samples were analyzed by a range of spectroscopic, chromatographic, and microscopic techniques.

The amount of drainage water varied extremely between the locations and lithologies. We attribute this both to the foremost migration pathway operative (i.e., fractures, fluid flow regime, fracture flow, and film-flow) and to the different spatial extents of the “capture zones” that recharge the drainage collectors. For all lithologies, pH and EC were found to be independent of the lithology with rather high contents of organic carbon and showed significant differences between the hydrological summer and winter season. Significant amounts of colloids and larger suspended particles of calcite, clay minerals (Illite), and quartz were identified in almost all samples. While the general hydrochemistry seems to be controlled by the biogeochemical processes in the topsoils, we presume that the percolating water collects the mobilizable materials from exposed interfaces in the AZ. These materials are made “susceptible” to release and transport by weathering within the AZ during the periods of no flow. Additionally, upwelling groundwater may also be replenished the inventory of mobilizable materials in the AZ. Our study suggests that the AZ is not just an “inert” transition zone, but has to be considered as a biogeochemical reactor that may severely alter the seepage composition and properties, and thus the groundwater recharge.