bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-emplacement fluid-driven intrusion fracturing and quartz-sand injections at the basal shear zone of the Esla Nappe (Cantabrian Zone, NW Iberia)
Authors: de Paz Álvarez Manuel Ignacio , Llana Fúnez Sergio , Alonso Juan Luis
Published: March 2020

The Esla Nappe is located in the external foreland and thrust belt of the Variscan Orogen in the NW Iberian Massif (Cantabrian Zone, NW Iberia). It is formed by a near-complete Palaeozoic sedimentary succession. With a displacement of around 19 km, the nappe was emplaced along a thin (<2–3 m) basal shear zone (ENBSZ) located at an estimated minimum depth of 4 km. Emplacement took place during the Moscovian (ca. 312 Ma). Fault-rock assemblages record a variety of alternating deformation mechanisms and processes, including cataclastic flow,  pressure solution and hydrofracturing and vein precipitation. All these processes are considered evidence of an aseismic stable behaviour of the ENBSZ, where deformation was influenced by secular variations in the fluid pore pressure.

Following emplacement, the ENBSZ was breached by clastic dykes and sills which were intruded following re-opened previous anisotropies, including bedding planes, thrust surfaces, joints and stylolites. Together, they constitute an interconnected network of quartz sand-rich lithosomes reaching structural heights occasionally exceeding 20 m above the ENBSZ. The orientation of the dykes suggests that the injection process took place under low differential stress conditions in the hangingwall, and near-lithostatic fluid pore overpressure conditions in the footwall. The injected slurry consisted of overpressured pore fluid, quartz-sand grains derived from the footwall and entrained host-derived fragments. Depending on fracture aperture and slurry composition, a variety of fluid velocities can be inferred in the order of 15–30 cm/s. Thin pure injections of quartz grains (ca. <1 cm) were characterised by a laminar flow (Re<2100), whereas the thickest quartz and host-derived mixed injections (~1 m) displayed a fully turbulent flow (Re~2 x 104).

The causes for the fluids to reach near-lithostatic fluid overpressures within the uppermost footwall remain unknown. It is not possible to rule out a seismic trigger, but the absence of extreme shear localization structures typical of seismic slip suggests that the injection process was driven by fluid progressive accumulation, possibly related with clay dehydration reactions, tectonic loading, pore compaction or fluid migration from underlying formations. Actual breaching and injection may have been allowed by a decrease in bedding-parallel compressive stresses in the Esla Nappe associated with the subsequent evolution of the thrust-wedge.
The impact of NAWDEX dropsonde and extra radiosonde observations on forecast quality and tropopause structure
Authors: Schindler Matthias , Weissmann Martin , Schäfler Andreas , Radnoti Gabor
Published: March 2020

Utilizing a multitude of in situ and remote sensing instruments, a comprehensive dataset was collected during the transatlantic field campaign NAWDEX in autumn 2016. Cycled data denial experiments with the global model of the ECMWF showed that additionally collected dropsonde and radiosonde observations contributed to a reduction in the short-range forecast error, with the most prominent error reductions being linked to Tropical Storm Karl, cyclones Matthew and Nicole and their subsequent interaction with the midlatitude waveguide. While the short-range forecast quality was improved, Schäfler et al. (2019, in review) demonstrated that ECMWF IFS analyses exhibit deficiencies in capturing observed wind speeds at and above the dynamical tropopause during NAWDEX. Therefore, data assimilation output from the ECMWF IFS is used to evaluate the observational influence on the tropopause. Statistics of data assimilation diagnostics such as the analysis increment and first guess departure will be assessed in observation space in a tropopause relative framework to quantify the impact of assimilated radiosonde observations on tropopause location and sharpness.
Field observations of subsurface flow path evolution over 10 Millennia
Authors: Hartmann Anne , Semenova Ekaterina , Weiler Markus , Blume Theresa
Published: March 2020

Where water goes when it rains, is to a large part controlled by subsurface storage and subsurface flow paths. While these aspects are essential for basic hydrological process understanding, their large spatial and temporal variability makes both systematic studies and extraction of generalizable results challenging.
We investigate systematically how subsurface storage and flow paths change during the temporal evolution of hillslopes. In order to do so we selected 4 moraines of different ages (30, 160, 3000 and 10.000 years) in a glacial foreland in the Swiss Alps. We then studied both soil physical characteristics as well as flow path evolution across this chronosequence by extensive sampling and soil physical laboratory analyses on the one hand and 36 in-situ dye tracer experiments (Brilliant Blue)  on the other hand.
We find that soil physical characteristics change significantly over the millennia. However, vegetational development seems to have a similarly strong effect on flow path evolution. Flow paths evolve from mainly matrix flow at the youngest moraine to increasingly more dominant preferential flow. At the oldest moraine we furthermore find increased subsurface storage, especially in the now strongly developed organic horizon. At intermediate ages preferential flow is less dominated by flow in macropores but is initiated at the soil surface through spatially variable vegetation and microtopography. With this study we provide a first systematic and detailed study of flow path evolution across the first ten millennia of hillslope evolution.
Coupling the dynamic vegetation model LPJmL5.1 to an Earth system model – towards POEM1.0
Authors: Drüke Markus , von Bloh Werner , Petri Stefan , Schaphoff Sibyll , Sakschewski Boris , Forkel Matthias , Huiskamp Willem , Feulner Georg , Thonicke Kirsten
Published: March 2020

Feedbacks between biosphere and other components of the Earth system are challenging to model accurately and therefore are often omitted or oversimplified in Earth system models (ESMs). However, their importance is increasingly recognized as rapid disturbances due to anthropogenic (e.g., deforestation) or natural (e.g. regional increase in fires) drivers are already observed.

Here we couple the well established and comprehensively validated dynamic global vegetation model LPJmL5.1 (von Bloh et al., 2018) to an Earth System model CM2Mc (MOM5/AM2, Galbraith et al. 2011). We replace the simple static vegetation model LaD with LPJmL5.1 and couple the water- and energy cycle by using GFDL’s Flexible Modeling System (FMS). In order to stabilize the model performance, several adjustments to LPJmL5.1 had to be done, including the introduction of a subdaily cycle for the energy and water calculations, the implementation of a conductance of the soil evaporation and plant interception, the calculation of a canopy layer humidity, and the surface energy balance in order to calculate the surface and canopy layer temperature within LPJmL5.1.

The coupled system allows us to answer questions regarding ecosystem stability with a complete energy and water cycle. For example, changes in the vegetation have a large impact on atmosphere dynamics, which in turn affects precipitation and feeds back into vegetation growth and mortality. To examine this feedback a simple experiment is performed by deforesting the whole Amazon basin and replacing it with grassland. Our results show decreasing precipitation and increasing canopy temperature which becomes a stable climate state in this treeless scenario. Future applications of the coupled model may include the investigation of tipping points in the biosphere, the impact of different atmospheric CO2 concentrations or climate change and land-use change scenarios.

 
Assessment of the role of green infrastructure in sustainable urban water management
Authors: Gulyás Ágnes , Csete Ákos
Published: March 2020

Due to the climate change caused uncertainty, the urban areas face new challenges. In addition to mitigating the negative effects, it is important the developments need to implemented in a sustainable manner. The problem of urban areas is substantial on account of their growing spatial size and population, furthermore the inadequate infrastructure. Urban districts with inadequate infrastructure can be a major source of water pollution, but also have a significant impact on the well-being of the citizens. In modern urban planning the sustainable urban water management based on the usage of green infrastructure. Green infrastructure is an important tool to make urban water cycle sustainable by linking artificial, engineered elements (gray infrastructure) with the services provided by vegetation. Green infrastructure can help to make the urban water cycle sustainable in many ways. Its primary role is the mitigating effect, such as reducing and retaining surface runoff with the process of interception and evaporation. Due to the complex structure of vegetation, it can also play an important role in infiltration (by root system), thus also reducing surface runoff.

Providing adequate data on the role of green infrastructure – even on a city-wide scale – can help decision makers. To accomplish this, hydrological models can play an important role. If these models (i-Tree Hydro) based on appropriate meteorological and land cover data, they can help to estimate the runoff and infiltration of study areas and the reducing effect of vegetation (interception, evaporation). In our study, we attempted to compare two significantly different urban district based on these aspects and to analyze the differences. Analyzes in the two study areas of Szeged (Hungary) all suggest the vegetation can significantly contribute to the reduction of surface runoff. Differences between these urban districts can be quantified so these data can serve as a basis for decision making in urban planning processes.

As another element of our research, we analyzed the relationship between surface runoff and infiltration in modeling study (SWMM) of rainwater harvesting systems in public institutions (kindergartens). In this part of the research, besides the efficiency of the rainwater harvesting systems, we got data about the extent of surface runoff, evaporation and infiltration on yard of kindergartens.
Application of back trajectory modelling to TROPOMI SO2 observations to retrieve sub-daily volcanic fluxes
Authors: Hayer Catherine , Burton Mike
Published: March 2020

The use of polar-orbiting satellite instruments to monitor volcanoes has been an established technique for decades. However, a major limitation is the temporal resolution provided by these satellite platforms. For UV instruments, one or occasionally two observations per day are possible for tropical latitudes, though an improved temporal resolution is seen at high latitudes. The SO2 altitude within the atmospheric column is usually highly unconstrained and is one of the largest sources of uncertainty within the SO2 retrieval. This method assigns a best-fit altitude to each pixel, instead of using a single value for the whole plume.

TROPOMI is an UV spectrometer, launched on the Sentinel-5P platform in October 2017. The instrument has a swath of 2600 km and a spatial resolution of 5.5x7.5 km (improving to 3.5x7.5 km from August 2019). Sentinel-5P flies with the A-Train constellation, with an equatorial overpass time of 13:30 local time.

Applying the NOAA HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) back trajectory model, the injection time, injection and measurement altitudes of the SO2 in each pixel within the satellite image is derived. Back trajectories are run for each pixel at a range of altitudes. The natural variability in the wind field at different altitudes (wind shear) means that only some of those trajectories will return to the volcano, constraining the measurement altitude to those trajectories. The SO2 concentration is interpolated to this altitude. Finding the point in the trajectory when it most closely approaches the volcano provides the time and altitude of injection.

Combining the corrected SO2 concentrations with the injection time produces the SO2 flux that generated the observed SO2 cloud, and with the injection altitude to calculate the mass eruption rate. These parameters can also be used to improve eruption plume modelling by improving the constraints on the eruption column characteristics.

The method is applied to the December 2019 eruption of White Island, New Zealand.
Using low cost sensors to assess soil temperature response to summer heatwaves in urban greenspaces.
Authors: Hannam Jacqueline , Nandozi Carolyn
Published: March 2020

Urban green spaces regulate city air temperatures, particularly mediating the urban heat island effect. Urban below ground temperature regulation is less studied, but known to have a significant effect on urban heating by regulating temperature through heat transfer and thermal conductivity. The impacts of climate change, such as the increased frequency and intensity of heatwaves, will exacerbate urban heating effects, having significant impact on urban citizens. We installed low cost temperature sensors in topsoils across a gradient of urban green spaces (parking lots, rewilded areas, managed grassland, biodiversity plots, woodland) in the Cranfield Urban Observatory (UK). The soil temperture sensors measured continously during June and July 2019 and included two periods of record breaking heatwaves in Europe in late June and July.  As expected, the results showed significant variations in soil temperature between the urban green space types, where parking lot soils showed higher and flasher temperature regimes compared with all other green spaces.  Urban woodland had significant dampening effects on soil temperatures. The managed green spaces responsed differently to the heatwave events and grassland soils retained heat for longer compared with areas planted with wildflower mixes (biodiversity plots).  Therefore, urban planning should prioritise the type of green spaces within urban developments to take into account the different regulatory effects of heat, particulaly under the projected effects of a changing climate.
Equality in Engineering-outcomes of a workshop (Bristol 2020)
Authors: Coraggio Elisa , Cairnes Thomas , Giani Giulia , Gnann Sebastian , Kiraz Melike , Noacco Valentina , Pianosi Francesca , Pregnolato Maria , Sarailidis Georgios , Stein Lina , Wang Lina
Published: March 2020

Science has a diversity problem, and engineering sciences are no exceptions. While equality and diversity issues are gaining attention and progress is being made, tackling discrimination and creating an inclusive environment remains an open challenge. Women, people belonging to minority groups and people with disabilities are under-represented in higher academic ranks, which may discourage early-career researchers of these groups to pursue a career in engineering sciences. Conscious and unconscious bias, insecurity in how to intervene in inappropriate situations, amongst other things, compromise both the potential of research groups and the well-being of individuals.

We will present the outcome of a one-day workshop that will be held in Bristol on the 2nd of April 2020: Equality in Engineering.  This is the "spin-off" of an event we organised last year for water scientists at the national level (UK), which attracted a lot of interest and where we were asked to organise an event specifically for PhD students in Engineering. Therefore, the workshop aims at educating and engaging Engineering PhD students on equality issues. PhD students had the opportunity to express their interests on specific topics on an online survey. Thus, we will invite speakers at different career stages to talk about problems related to 1) Work-life balance (e.g. parenting & maintaining a career in academia), 2) The importance of role models and lack of leaders from minority groups and 3) unconscious biases and micro-inequalities. The discussions will be followed by a practical training session on race/ethnicity, equality and privilege. Finally, a group discussions session will be held aiming at identifying major issues related to equality in engineering, which still restrain an inclusive academic environment and ideas on how to overcome these issues. Moreover, during this session participants will have the opportunity to exchange ideas and reflect upon the things highlighted during the previous sessions.

We aspire that the outcomes of this discussion can serve as a call or guideline for future actions, both at the local scale and at the institutional level (e.g. larger research organisations such as the EGU). We also hope to initiate or follow-up on discussions during the EGU General Assembly as we regard overcoming equality-related issues in our society as an ongoing process.
Dynamical phenomena in the atmosphere of Mars imaged with the Visual Monitoring Camera onboard Mars Express
Authors: del Río-Gaztelurrutia Teresa , Sánchez-Lavega Agustín , Hernández-Bernal Jorge , Hueso Ricardo , Cardesín-Moinelo Alejandro , Ravanis Eleni , Martin Patrick , Wood Simon , Titov Dmitri
Published: March 2020

The Visual Monitoring Camera on board Mars Express provides images of varied resolutions, covering a wide range of locations and seasons, and has been taking images for several Martian years. This large image database can be exploited to study various dynamical phenomena, and in this work, we concentrate on the study of cloud and dust storm activity in the polar regions, describing vortices, cloud evolution, and regional dust storms as well as the presence of gravity waves. Tracking the motions of details in the images, we estimate local winds, compare our results with predictions from the Mars Climate Database in different scenari, and study their seasonal evolution and potential inter annual variability. Further, resolution of images captured near pericenter is sufficient to allow the detection of gravity waves in the troposphere, identified as regular patterns in the cloud fields. We measure some of the basic properties of these waves, such as horizontal wave vector and extension of wave trains. We analyse those properties in relation to their aerographic location, local time and season, in the context of a recent study of the distribution of gravity waves on the lower atmosphere of Mars as inferred from the analysis of temperature fields by the Mars Climate Sounder onboard the Mars Reconnaissance Orbiter (MRO) (Heavens et al. ICARUS 2020).
Evolution of Quaternary cave levels in low-relief karst regions: influence of fluvial incision and speleoinception of chalk caves in northern France
Authors: Ballesteros Daniel , Nehme Carole , Farrant Andrew , Todisco Dominique , Sahy Diana , Grappone J. Michael , Mouralis Damase
Published: March 2020

In many lowland areas, fluvial incision is usually relatively slowly and another factors as the stratigraphical control would play a relevant role. In the lower Seine valley of Northern France, cave systems developed in the sub-horizontal Upper Cretaceous chalk of the Anglo-Paris Basin offer the potential to constrain the Quaternary evolution of the Seine valley and to test the role of speleo-inception theory of conduit development in the chalk aquifer. Six chalk caves, with a combined length of over 5.7 km were studied in detail. In each studied cave, data on the passage morphology, cave deposits (speleothem and sediments) and stratigraphical control were recorded. Cave levels were defined based on geomorphological evidence and altitudinal cave passage analyses. The chronology of cave development and abandonment was constrained by ten U-Th speleothem dates and 144 palaeomagnetic samples collected from laminated sediments within the caves. Four regional cave levels were identified at 10, 40, 75-80, and 85-90 m asl, showing 1% slope to the Seine estuary. Each cave level is formed by phreatic and epiphreatic conduits enlarged by paragenesis, showing branch work or maze patterns. Cave infill corresponds mainly to clayey to silty sediments that occupy the majority of the karst conduits. Locally, sands and pebbles occur, and speleothems are relatively scarce. Palaeomagnetic and U-Th data show that these cave levels developed sequentially from >1.06 ka to c. 300 ka, ca. 78% of them in relation to prominent Turonian, Coniacian and Santonian hardgrounds as well as sheet- and semi-tabular flint bands. Their age correlates with the estimated age of the lower river terraces from limited previously published OSL, palaeontological and U-Th dating, although new age data from the study cave improve the chronology of the higher-level river terraces. The combination of all this data suggests an initial slow rate of incision during the early Pleistocene, followed by a phase of more rapid river incision up to ~ 0.30 m·ka-1 from ca. 1 to 0.7 Ma. Later, incision rates dropped to ~0.08 m·ka-1 during Middle Pleistocene, and 0.05 m·ka-1 since the beginning of the Upper Pleistocene. In conclusion, fluvial incision constitutes also a relevant speleogenic factor in low-gradient areas as the Seine Basin, where conduit development was favoured at sites where suitable lithological inception horizons intercept the contemporary base level.
Camera Observation and Modelling of 4D Tracer Dispersion in the Atmosphere
Authors: Stebel Kerstin , Cassiani Massimo , Ardeshiri Hamidreza , Bernardo Cirilo , Dinger Anna Solvejg , Kylling Arve , Park Soon-Young , Pisso Ignacio , Schmidbauer Norbert , Stohl Andreas
Published: March 2020

In the frame of the COMTESSA (Camera Observation and Modelling of 4D Tracer Dispersion in the Atmosphere) project, tracer dispersion release experiments were performed during three field campaigns in Norway in July 2017, 2018, and 2019.  The main goal of the project is to improve our understanding of turbulence and plume dispersion on local scale in the planetary boundary layer by bringing together full four-dimensional (space and time) observations of a (nearly) passive tracer (sulfur dioxide, SO2), with advanced data analysis and turbulence and dispersion modelling. By means of tomographic reconstruction of the 3D tracer concentration distribution, not only the mean but also higher moments of the probability density function of the tracer concentration field can be revealed. In 2017 first field tests were made, releasing SO2 in continuous plumes and puffs from a 10 m tower, while in the following years SO2 was released from a 60 m tower, located in the centre of a fenced-in 900 m x 400 m wide flat gravel field. The masts were equipped with eddy covariance measurement systems to continuously record turbulent fluxes of heat and momentum during the field campaigns. Up to six ultraviolet (UV) and in 2019 also three infrared (IR) SO2 cameras, were placed in a ring around the SO2 release tower at varying distances up to ~1.2 km to simultaneously image the movement and spread of the 2d integrated SO2 tracer column densities.

Here we present an overview of the field experiments and lessons learned, with focus on results from the 2019 summer campaign. It was a challenge to find a location where hazardous gas could be released and a main obstacle for the imaging-based experiment were the unfavourable weather conditions. Despite these challenges, progress was made throughout the years. During consecutive summers the release equipment was improved and optimized and in 2019 puff releases were made by filling balloons with SO2 and exploding them. The cameras were continuously developed, the setup of the cameras at the site was adjusted to allow observations for longer timescales.  During July 11-28, 2019 ~130 puffs were released from balloons holding between 250 g and 325 g SO2. Those are used to give an overview of the image/data processing and type of results that can be obtained from our observations, e.g. relative dispersion and meandering, Eulerian and Lagrangian integral time scales and their relation, tomographic reconstruction. The focus lies on the plume spread, i.e. relative dispersion processes we recorded under different stability conditions in July 2019.
Polarisation preservation in multi-mode optical quartz fibres and implications for MAX-DOAS observations
Authors: Oehmke Verena , Tirpitz Jan-Lukas , Frieß Udo , Platt Ulrich
Published: March 2020

In many spectroscopic applications, optical fibres are an essential part of the instrumental setup. One of such applications is Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS), which is a remote sensing technique to detect atmospheric aerosol and trace gases by analysing spectra of scattered skylight. Typically, multi-mode quartz fibres (MMQF) of > 100 µm in diameter are used in MAX-DOAS instruments to interconnect the telescope unit with a grating spectrometer. Besides acting as a light guide giving more freedom in the spatial arrangement of telescope and spectrometer and homogenizing the illumination of the spectrometer entrance slit, such fibres have depolarising properties originating predominantly from manufacturing induced birefringent effects. This property is particularly desirable in MAX-DOAS applications, since the incoming partially polarized skylight should ideally be depolarized before entering the polarisation sensitive spectrometer. The behaviour of polarised light in mono-mode fibres is well investigated and even utilized in telecommunications, whereas equivalent literature on multi-mode fibres is scarce.

We measured the depolarisation capabilities of a set of 20 MMQF of different age, length and diameter as typically used in MAX-DOAS applications. Independent of the fibre diameter, we found that in some recently manufactured (in 2018) fibres polarisation is well preserved with a decrease in total degree of polarisation (DOLP) to 1/e of its initial value at a fibre length Le > 10 m at 450 nm, while in older fibres (> 10 years in age) Le ≈ 1 m was found. This is probably due to improvements in the manufacturing process in the recent years. We further investigated the dependence of Le on wavelength, on the polarisation orientation of the ingoing light and on additional birefringence induced by applying external strain (bending) to the fibres. The results are presented and discussed with regard to their implications for MAX-DOAS observations.
Automated recognition and picking of foraminifera using the MiSo (microfossil sorter) prototype
Authors: de Garidel-Thoron Thibault , Marchant Ross , Tetard Martin , Adebayo Michael , Gally Yves
Published: March 2020

Recent progresses in image processing, and image recognition have paved the way for automated procedures to classify natural objects such as foraminifera. Foraminifera are among the most useful tracers in biostratigraphy and paleoceanography. Yet, the protocol used to extract and recognize the foraminifera has not changed since the mid-18thcentury: manual picking using a brush with a stereomicroscope.

 

Here we present the results we achieve by developing the MiSo - Microfossil Sorter - automaton, to automatically pick microfossils from the sediment coarse fraction. This automated system, built with ATG Technologies, is fully operational and works 24/7 at CEREGE. In this study, we will detail the basic workflow of the automaton, processing ~8000 particles/day, and its ability to cope with the large morphological and structural variability of particles encountered in real, marginal to deep-sea sediments. We use convolutional neural networks adapted and trained on deep sea sediment samples to classify the coarse sediment particles, including planktonic and benthic foraminifera.

 

As a test case, we will compare paleoceanographic records generated by a micropaleontologist with the ones generated by our automaton: relative abundance, fragmentation rate, biometrical changes. We have studied two deep-sea cores from the equatorial Pacific to document past hydrographic changes in the late Quaternary, achieving millennial scale resolution through the last deglaciation. Using the automaton, we processed more than 500,000 foraminifera. The accuracy of recognition typically ranges around 85 to 95% depending of the morphoclasses and of the CNN used for the training. Morphoclass size probability density function and assemblages derived from the CNN will be compared to multi-proxy (micropaleontological and geochemical) records. We will discuss the ongoing applications of our workflow, from foraminifera to pteropods in deep sea sediments, and the recent updates of our system.
Are abandoned rifts tectonically active? Morphotectonic evidence from the Gulf of Suez
Authors: Fernández-Blanco David , de Gelder Gino , Jackson Christopher A-L.
Published: March 2020

Intra-continental abandoned rifts can fail for many reasons and are typically considered to be tectonically inactive. It is widely thought that the Oligo-Miocene Suez Rift, Egypt, which is located at the propagating northern end of the Red Sea spreading ridge, was abandoned in the Pliocene when motion between the African and Arabian plates was accommodated instead by the sinistral Dead Sea transform fault. However, local evidence for Plio-Quaternary normal faulting, the presence of uplifted Quaternary shorelines along the rift margins, and low-magnitude but widespread seismicity, together suggest the Suez Rift is tectonically active. Here, we present the first detailed analysis of this post-“abandonment” tectonic activity. We analyze the fluvial and tectonic geomorphology of the rift using freely available, 30 m-horizontal resolution digital elevation models (DEMs). These data reveal widespread normal fault offsets of Plio-Quaternary rocks at outcrop-to-basin scale, even in rift sectors >250 km north of the southern terminus of the rift. River morphology, tectonic knickpoints, normalized steepness indexes (ksn), and chi (χ) maps also provide evidence for relatively young faulting. Uplifted Quaternary shorelines show that active normal faults have footwall uplift rates of up to 0.125 mm/yr, even in locations >200 km north of the rift terminus, with these rates being relatively consistent for both rift margins. Our preliminary results provide clear evidence for young and ongoing tectonic activity in the Suez Rift and thus question the notion that this evolving plate boundary is currently in a state of complete tectonic quiescence. We speculate that the present tectonic activity in the Suez Rift results from the translation of far-field stresses imposed by the Afar plume, or by a recent change in the Eulerian pole of rotation between the African and the Arabian plates. Our results call for further analyses of the recent rifting in the Suez Rift and the exploration of recent activity in other “abandoned” rifts.
Aircraft observations of a new DMS oxidation product over the North Atlantic using a HR-ToF-CIMS
Authors: Matthews Emily , Bannan Thomas , Mehra Archit , Archibald Alexander , Wu Huihui , Williams Paul , Lee James , Veres Patrick , Percival Carl , Coe Hugh , Gallagher Martin
Published: March 2020

Marine ecosystems are an important component of the climate feedback system. One of the main pathways for ocean-climate interaction is through the oxidation of DMS (dimethyl sulphide), a gas released from phytoplankton in the sea surface. DMS derived products are known to be important in marine cloud formation and the Earth’s radiation budget. Aerosol-Cloud interactions currently represent the largest uncertainty in climate modelling (Boucher et al., 2013). Our research focuses on airborne measurements using real-time high resolution instruments to identify and quantify trace oceanic biogenic gases on board the FAAM research aircraft. Here we present aircraft measurements made over the North Atlantic ocean using a HR-ToF-CIMS, across three seasons during the most recent ACSIS/ARNA campaigns. Here we report some of the first observations of an alternative DMS oxidation product, hydperoxymethyl thioformate (HPMFT) using chemical ionisation mass spectrometry with iodide reagent ion. Observations of this novel species have never been reported in the atmosphere but laboratory studies suggest that the main oxidation route of DMS occurs through this species, in certain environments (Berndt et al., 2019). This has potentially significant climate implications, none of which are currently represented in global climate models. The fate of this newly measured species once in the atmosphere is uncertain but is likely to alter our understanding of the marine sulphur cycle. These observations along with laboratory and modelling studies will aid in being able to understand the role of HPMFT in the ocean-climate feedback system.

References

T. Berndt, W. Scholz, B. Mentler, L. Fischer, E. H. Hoffmann, A. Tilgner, N. Hyttinen, N. L. Prisle, A. Hansel, and H. Herrmann, The Journal of Physical Chemistry Letters 2019 10 (21), 6478-6483,DOI: 10.1021/acs.jpclett.9b02567

Boucher O, Randall D, Artaxo P, Bretherton C, Feingold G, Forster P, Kerminen VM, Kondo Y, Liao H, Lohmann U, Rasch P, Satheesh S, Sherwood S, Stevens B, Zhang X. In: Clouds and aerosols. Cambridge: Cambridge University Press; 2013. United Kingdom and new york, NY, USA, book section Chapter 7, pp 571–658. https://doi.org/10.1017/CBO9781107415324.016.

 

 

 
Seismic soil class map for Italy according to European and Italian codes map
Authors: Forte Giovanni , Chioccarelli Eugenio , De Falco Melania , Cito Pasquale , Santo Antonio , Iervolino Iunio
Published: March 2020

Soil conditions affect ground motion amplification. Thus, seismic site classification is a critical issue to predict ground motion parameters in the context of both probabilistic seismic hazard analysis and real-time generation of shaking maps. Especially on large areas, simplified procedures for estimating the seismic soil amplification can be advantageous. In order to account for these local effects, some proxies which account for the soil behaviour can be identified; e.g., the average shear-wave velocity of the upper 30 m (VS,30), or the equivalent shear-wave velocity from the depth of the seismic bedrock (VS,eq). 
In this study, two maps of seismic shallow soil classification for Italy according to Eurocode 8 (EC08) and the new Italian Building Code (ItBC2018) are presented. The methodology from which the maps are derived is described in Forte et al. (2019) and accounts for two sources of information: site-specific measurements and large-scale geological maps. The soil maps are obtained via a four-step procedure: 
(1) a database of about four-thousand shear-waves velocity (Vs) measurements coming from in-hole tests, surface geophysical tests and microtremors is built, covering (unevenly) the whole national territory; 
(2) twenty geo-lithological complexes are identified from the available geological maps; 
(3) the investigations are grouped as a function of the geo-lithological complex and the distribution of measured VS,30, VS,eq are derived;
(4) medians and standard deviations of such distributions are assumed to be representative of the corresponding complexes that are consequently associated to soil classes. 
The EC08 soil class map and the available database of Vs measurements were compared with the seismic soil map provided by the USGS based on a topographic slope-proxy (Allen and Wald, 2007). The latter is obtained by the correlation between topographic slope and VS,30, assuming morphometrical characteristics of the terrain as representative of the lithology. The slope-based method appears less reliable than the proposed approach, because its predictions resulted in a slight but systematic overestimation of the measured soil classes. Therefore, the proposed map can be more suitable for large-scale seismic risk studies, despite it is not a substitute of seismic microzonation and local site response analyses.
To make the results of the study available, a stand-alone software “SSC-Italy” has been developed and is freely available at http://wpage. unina.it/iuniervo/SSC-Italy.zip. 
Extreme storms in regions of steep morphology. The case of the 2016 Messenia flood event
Authors: Skourtsos Emmanuel , Diakakis Michael , Filis Christos , Kranis Haralambos , Mavroulis Spyridon , Lekkas Efthymios
Published: March 2020

During the late afternoon and early morning hours of September 7, 2016, an intense storm hit the wider area of the Kalamata Municipality, Greece, affecting large parts of SW and SE Peloponnese. The storm caused three deaths, dozens of homeless people, damages to hundreds of homes and cars, huge losses in agricultural production and livestock, as well as effects on the road network, on schools and water and electricity utilities. The settlements of Pidima and Thouria and the city of Kalamata itself, situated on the interface between the flat and mountainous terrain of Messenia region were particularly affected by the overflow of local streams.

Rainfall intensity reached up to 162.2mm in one and a half hour at Arfara station of the National Athens Observatory, 15 km north of Kalamata City, while Kalamata and Kardamili stations received 102 mm and 107.8 mm in 50 minutes respectively.

The rainfall that had preceded the storm the previous day had been two to three times the average monthly values of the stations for September. This event caused the saturation of the surficial part of the geological formations, which combined with the high intensity of precipitation of the second day of rainfall and the high morphological gradients of the mountainous area, led to an increase in surface runoff with high proportion of solid materials.

The storm caused multiple flash floods in the region affecting mostly small catchments drained by ephemeral torrents that caused flooding and severe damages in the city of Kalamata as well as the settlements of Pidima and Thouria and others. The phenomena and their impacts clustered notably near the border between the mountainous and flat terrain affecting heavily the towns situated along it. Larger rivers in the area (Ari and Pamisos Rivers) as well as the formerly swampy areas were affected but phenomena and impacts recorded notably less intensity. Small debris flows triggered by the storm were also limited to the border between the two types of terrains and caused damages mostly on the infrastructure developed there.

Overall, the distribution of impacts as well as the characteristics of the floods and debris flow phenomena showed that regions on the interface between mountainous terrain with steep slopes and flat regions present particularly high levels of hazard at the border between the two, whereas the intensity tends to reduce gradually downstream.
Understanding the role of seawater vacuolisation in the biomineralisation of planktonic foraminifera using confocal microscopy
Authors: Evans David , Erez Jonathan , Müller Wolfgang
Published: March 2020

The calcite shells of planktonic foraminfera are a key archive for palaeoceanic reconstruction and represent one of the largest sinks of carbon from the surface ocean. Therefore, understanding the biomineralisation process of these organisms, and how responsive it is to ocean acidification, is an important part of accurately predicting the carbon cycle response to past and future climate change events. To date, the majority of the direct observational evidence on which foraminifera biomineralisation models are based comes from shallow-dwelling benthic species. Whilst this has provided a large amount of important information, it is not known how applicable these models are to the low-Mg planktonic foraminifera. In particular, key questions regarding the relative importance of seawater vacuolisation (SWV) versus calcium transmembrane transport (TMT) remain unresolved. We present the results of fluorescent labelling experiments on intact, decalcified planktonic foraminifera (Globigerinoides ruber and Globigerinella siphonifera) using the cell-impermeable dyes calcein, FITC-dextran, and SNARF-dextran, enabling direct observation of seawater vacuoles within the cell via confocal microscopy. Our results indicate that seawater endocytosis plays a dominant role in the calcification process. Seawater vacuoles can make up a large proportion of the intracellular volume, with a residence time on the order of hours. Moreover, we show that the skeleton is labelled with fluorescent dyes such that seawater derived from these vacuoles must be present at the calcification site. Along with inferences based on geochemical data [Evans et al., 2018], our results strongly argue that biomineralisation models centred on seawater endocytosis are applicable to the planktonic foraminifera.

Evans, D., Erez, J., Müller, W. [2018] Assessing foraminifera biomineralisation models through trace element data of cultures under variable seawater chemistry. GCA 236:198.
The Impacts of Substorms on the Ring Current
Authors: Sandhu Jasmine , Rae Jonathan , Walach Maria-Theresia , Watt Clare , Freeman Mervyn , Gkioulidou Matina , Forsyth Colin , Reeves Geoffrey , Spence Harlan , Hartley David , Meredith Nigel , Ross Johnathan
Published: March 2020

Substorms are a highly dynamic process that results in the global redistribution of energy within the magnetosphere. The occurrence of a substorm can provide the inner magnetosphere with hot ions and consequently intensify the ring current population. However, substorms are a highly variable phenomenon that can occur as an isolated event or as part of a sequence. In this study we investigate how substorms shape the energy content, anisotropy, and storm time behaviour of the ring current population.

Using ion observations (H+, O+, and He+) from the RBSPICE and HOPE instruments onboard the Van Allen Probes, we quantify how the total ring current energy content and ring current anisotropy changes during the substorm process. A statistical analysis demonstrates the impact of a typical substorm energises the ring current by 12% on average. The features of the energy enhancement correlate well with the expected properties of particle injections into the inner magnetosphere, and large enhancements in the O+ contribution to the energy content suggest important compositional variations.

Analysis also shows that the ring current ions experience significant isotropisation following substorm onset. Although previously attributed to enhanced EMIC wave activity, a consideration of different drivers of the isotropisation identifies that although EMIC wave activity plays a role, the properties of the injected and convected population is the dominant driver.

Finally, we explore the storm time variations of the ring current, revealing important information on the role of substorms in storm dynamics. A superposed epoch analysis of ring current energy content shows large enhancements particularly in the premidnight sector during the main phase, and a reduction in both local time asymmetry and intensity during the recovery phase. A comparison with estimated energy content using the Sym-H index was conducted. In agreement with previous results, the Sym-H index significantly overestimates energy content. A new finding is an observed temporal discrepancy, where estimates maximise ~ 12 hours earlier than the in-situ observations. We assert that an observed enhancement in substorm activity coincident with the Sym-H recovery is responsible. The results highlight the drawbacks of ring current indices and emphasise the impacts of substorms on the ring current population.
A profile of the Io dust cloud and plasma torus as observed from Juno
Authors: Jørgensen John L. , Denver Troelz , Benn Mathias , Jørgensen Peter S. , Herceg Matija , Merayo Jose M. G. , Connerney John E. P.
Published: March 2020

The Juno MAG investigation’s dedicated star tracker, the Advanced Stellar Compass (ASC), has continuously monitored high energy particles fluxes in Jupiter’s magnetosphere subsequent to Juno’s orbit insertion on July 4, 2016. The ASC primary function is to provide an accurate inertial attitude reference, however, the most energetic particles in Jupiter’s trapped population is capable of penetrating the radiation shield of the ASC where they are registered. Such particles have energy >15MeV for electrons, >80MeV for protons, and >~GeV for heavier elements. With a sample cadence of 250ms, the ASC renders a detailed mapping of the trapped particles throughout space traversed by Juno. The particles travelling along the magnetic field lines crossing near the orbit of Io will be strongly influenced by interaction with any matter, moon, dust or plasma, which happens to be in their trajectory. The relativistic particle flux monitored, is highly relativistic, and has as such a modest retention time in any drift shell. The short lifetime of the trapped particles, and the constant scanning of field lines connecting to the Io environment enables a detailed profiling of the dust and plasma density, as well as the effect to/from Io itself. We present the measurement and their implications for the azimuthal and radial dust cloud and plasma torus.
Evaluation of convective lifecycles in convection permitting weather forecasts for tropical Africa.
Authors: Hill Peter , Stein Thorwald , Cafaro Carlo , Woodhams Beth , Webster Stuart
Published: March 2020

Tropical Africa is subject to weather extremes at a variety of space- and time-scales, leading to droughts, floods and severe storms. The weather has a huge impact on the local population: droughts and floods impact on weather dependent industries such as agriculture or fishing, which much of the population rely on for their livelihoods, while severe storms can lead to destruction of property and even loss of life. Despite this, global numerical weather prediction performance remains notoriously poor in tropical Africa, particularly at smaller scales.

The UK Met Office has recently begun running an ensemble weather forecasting system for tropical Africa at convection permitting scale (4.4 km). This forecasting system clearly has enormous potential to enable improved weather forecasts in  tropical Africa. Previous studies indicate that convection permitting models can provide greater skill than lower resolution global models for sub-regions within tropical Africa. However, skill remains fairly poor and further evaluation work is necessary to identify potential model improvements.

This presentation describes an evaluation of the lifecycles of convective systems in the UK Met Office tropical Africa model. 10.8 micron brightness temperatures are used to identify and follow convective systems both in the model and in geostationary satellite observations, which provide both high temporal (15 minute) and spatial (~3 km) resolution. We evaluate the size, diurnal cycle, propagation, initiation and lifecycle of convective systems in the model and the link between these properties and the magnitude of surface precipitation produced. Finally we analyse and evaluate the response of storm systems and hence precipitation in the model to large scale atmospheric drivers such as the Madden-Julian Oscillation and African easterly waves. This process oriented evaluation helps identify of the causes of model errors, facilitating future improvements in the model.