bluuebunny/crossref_metadata_2025 huggingface dataset:
Archeomagnetic investigation of textile ceramics from Grishinsky Istok III  settlement  (Oka  Region, Ryazan district, Russia)
Authors: Pilipenko Olga , Nachasova Inga , Azarov Evgenii
Published: March 2022

The goal of our research is to obtain new data of geomagnetic field intensity in the Eastern Europe in the Bronze Age.  The arhaeomagnetic study of fired ceramic from the Grishinsky Istok III settlement was done. The settlement Grishinsky Istok III is situated in the Oka region of Ryazan district of Russia (54о41′, 40о57′). The studied collection of pottery fragments of that archaeological site pertains to the “textile” ceramics of Bronze Age.  The age of pottery fragments corresponds to the ~ 1500-1300 years B.C. The composition of the ferromagnetic fraction of the studied samples has been examined by the thermo-magnetic analysis.   The dependence of the saturation magnetic moment on temperature in the magnetic field and determination of the Curie points were carry out with an analyzer of ferromagnetic fraction. Thus based on the thermo-magnetic analysis one can conclude that the main carrier of the thermo remanent magnetization of the samples is relatively resistant to heat maghemite. The size of grains lies in a pseudo single domain area. The determination of the ancient magnetic field intensity was carried out by modified Thellier method. Fifteen geomagnetic field intensity determinations were obtained. The geomagnetic field intensity varies between 37 and 66 µT with an average value of about 50 µT.  Acquisition of new data about the Earth’s magnetic field during the Bronze Age makes it possible to advance the studies of geomagnetic variations. This work was supported by the Russian Foundation for Basic Research, project no. 19-55-18006 and the State task of the Schmidt Institute of Physics of the Earth RAS no. 0144-2019-0006.
Halogen measurements with in-situ sampling techniques: Studies at Vulcano and Mt. Etna (Italy)
Authors: Geil Bastien , Gutiérrez Xochilt , Karbach Niklas , Bobrowski Nicole , Hoffmann Thorsten
Published: March 2022

Halogens in volcanic plumes are important for both volcanic and environmental research. For example, changes in the composition of the volcanic plume can be an indication of changes in the activity of the volcano. In addition to entrained air components, volcanic plumes consist mainly of SO2, CO2, and H2O. However, HF, HCl and HBr are also significant constituents of volcanic emissions. A particularly interesting element in this context is bromine because of its atmospheric relevance, but also since BrO forms in the volcanic plume and, like SO2, can be determined spectroscopically using remote sensing techniques, making it ideal for monitoring and surveillance of volcanoes. However, to interpret and use BrO concentrations, we need a fully understanding of the formation and evolution of BrO in volcanic plumes. A step forward can be gained by measuring all relevant halogen species.

Currently, several methods are used to detect the various halogen compounds. Remote sensing methods exist for only a few so we use in-situ sampling methods such as diffusion separators, filter packs or aqueous alkali traps to collect reactive and total halogen species, respectively.

In this study, we will present the results of total fluorine, chlorine, bromine and sulfur as well as CO2 and their ratios between, for field campaigns at a closed volcanic system - Vulcano in September 2019 and October 2020 and at an open vent volcano Mt Etna in July 2021. The results will be discussed in the light of the different degassing activity and therefore different temperature and will be compared to earlier studies at Masaya, Nyamulagira and Etna.
What family of Radial Basis Functions to use in Direct Policy Search? A comparative analysis 
Authors: Kwakkel Jan , Zatarian-Salazar Jazmin
Published: March 2022

Direct policy search (DPS) is increasingly being used to flexibly design policies for multi-objective reservoir control. DPS is a promising approach that can easily find policies for many heterogenous objective functions, particularly when coupling global approximators with evolutionary algorithms. Nonetheless, specifying the topology and the family of global approximators, i.e., radial basis functions, is usually done by trial and error for practical applications and is often not reported in the literature. How does the selected family of radial basis functions affect the quality of the resulting control policies? Does the chosen family influence the search behavior of the evolutionary algorithms? Can we formulate recommendations for which families are more or less suitable in general, or given the characteristics of the control problem? We test a suite of radial basis functions to address these questions for finding Pareto optimal reservoir control policies using an established reference case. This reference case is the Conowingo reservoir, a transboundary water body in the Susquehanna River Basin in North-East US. The reservoir needs to meet multiple competing water needs for hydropower production, environmental flows, recreation, cooling water for Peach Bottom atomic power plant, and urban water supply for Baltimore, MD, and Chester, PA. To optimize the Pareto optimal reservoir control policies, we use the e-NSGA2 algorithm. Our study shows the effect of using different families of radial basis functions, particularly their impact on the recommended reservoir operations, the resulting tradeoffs across the different sectors, and the search behavior of the evolutionary algorithm.
Identification of microbial methane sources and sinks in an aquifer-fed continental wetland with a multi-omics approach
Authors: Coffinet Sarah , Dufresne Alexis , Quaiser Achim , Hinrichs Kai-Uwe , Laverman Anniet
Published: March 2022

Vegetated continental wetlands are responsible for 20% of global methane emissions. Wetlands encompass very diverse ecosystems, from ponds to peatlands. In mid-latitudes, temporary flooded lowlands are very common, due to the seasonal discharge of water from rivers or groundwater but their contribution to the global methane budget is unknown. These sites experience temporal successions of oxic and anoxic conditions and the impact of these dynamic redox conditions on the microbial communities is poorly understood. In particular, methanogenesis typically requires anoxic conditions while aerobic methanotrophy can oxidize large amounts of methane before it reaches the atmosphere. This study is carried out at the Ploemeur-Guidel hydrogeological observatory, where a wetland is created by the seasonal discharge of deep anoxic and iron-rich groundwater. Four one-meter-long cores were recovered along a transect from the inner to the outer side of the wetland and samples were collected every 20 to 30 cm along each core. Batch incubations revealed two potential hotspots of methane production at ca. 40 cm and 100 cm depth, reaching up to 3.5 µmol cm-3 d-1, in agreement with highest methane concentrations measured in the porewater collected at these depths. To shed light on the microbial processes involved in the methane cycling at this site, a metagenomic and metatranscriptomic analysis was conducted in combination with the analysis of the carbon isotopic composition of microbial intact polar lipids. Preliminary results of the omics study showed clear taxon stratification with depth. The proportion of metagenomic reads classified to archaeal taxa increased with depth and reached up to 15% of the total analyzed reads at one meter below the surface. Interestingly, the percentage of reads affiliated to known methanogens was highest at the surface (ca. 40% of the archaeal reads) and decreased with depth (ca. 13% at 100 cm depth). Archaeal communities appeared to be dominated by Candidatus Bathyarchaeota since up to 60% of the archaeal reads could be classified to this phylum. Carbon isotopic composition of the phytane and biphytanes (BP) derived from the major archaeal membrane lipids (archaeols and glycerol dibiphytanyl glycerol tetraethers, GDGTs) displayed a predominant heterotrophic signature. However, BP-2, derived from GDGTs with multiple rings was systematically depleted in 13C, suggesting autotrophic and/or methanogenic metabolism. Further statistical treatments will be performed to refine the taxonomic links between the detected membrane lipids and the archaeal populations along the cores.
In-situ mechanical testing and characterization of olivine grain boundaries
Authors: Avadanii Diana , Hansen Lars , Darnbrough Ed , Marquardt Katharina , Armstrong David , Wilkinson Angus
Published: March 2022

The mechanics of olivine deformation play a key role in long-term planetary processes, such as the response of the lithosphere to tectonic loading or the response of the solid Earth to tidal forces, and in short-term processes, such as the evolution of roughness on oceanic fault surfaces or postseismic creep within the upper mantle. Many previous studies have emphasized the importance of grain-size effects in the deformation of olivine. However, most of our understanding of the role of grain boundaries in the deformation of olivine is inferred from comparison of experiments on single crystals to experiments on polycrystalline samples.

To directly observe and quantify the mechanical properties of olivine grain boundaries, we use high-precision mechanical testing of synthetic forsterite bicrystals with well characterised interfaces. We conduct in-situ micropillar compression tests at high-temperature (700°C) on low-angle (13° tilt about [100] on (015)) and high-angle (60° tilt about [100] on (011)) grain boundaries. In these experiments, the boundary is contained within the micropillar and oriented at 45° to the loading direction to promote shear along the boundary. In these in-situ tests, we observe differences in deformation style between the pillars containing the grain boundary and the pillars in the crystal interior. In-situ observations and analysis of the mechanical data indicate that pillars containing the grain boundary consistently support elastic loading to higher stresses than pillars without a grain boundary. Moreover, only the pillars without a grain boundary display evidence of sustained plasticity and slip-band formation. Post-deformation advanced microstructural characterization (STEM) confirms that under the conditions of these deformation experiments, sliding did not occur along the grain boundary. These observations support the hypothesis that grain boundaries are stronger than the crystal interior. 

These experiments on small deformation volumes allow us to qualitatively explore the differences between the crystal interior and regions containing grain boundaries. Overall, the variation in strain and temperature in our small scale experiments allows fundamental investigation of the response of well characterised forsterite grain boundaries to deformation. 
Identifying and tracking surface-attached vortices in free-surface turbulence from above: a simple computer vision method 
Authors: Babiker Omer , Bjerkebæk Ivar , Xuan Anqing , Shen Lian , Ellingsen Simen Å.
Published: March 2022

Turbulence close beneath a free surface leaves recognisable imprints on the surface itself. The ability to identify and quantify long-lived coherent turbulent features from their surface manifestations only could open up possibilities for remote sensing of the near-surface turbulent environment, e.g., for assimilation into ocean models. Our work concerns automatic detection of one type of surface feature – “dimples” in the surface due to surface-attached “bathtub” vortices – based solely on the surface elevation as a function of time and space. 

Two-dimensional continuous wavelet transformations are used together with criteria for eccentricity and persistence in time, to identify candidate surface-attached vortices and track their motion. We develop and test the method from direct numerical simulation (DNS) data of turbulence influenced – and influencing – a fully nonlinear, deformable free surface.  

Comparison with the vertical vorticity in a plane close beneath the surface reveals that the method is able to identify long-lived vortical structures with a high degree of accuracy. Further tests of success rate included the vortex core identification method of Jeong and Hussain (1995). Different mother wavelets were tested, showing that the simplest option – the Mexican hat – outperforms more advanced options. 

Jeong, J., & Hussain, F. (1995). On the identification of a vortex. Journal of fluid mechanics, 285 69-94. 
A novel method for thermo-hydro-chemical models for Aquifer Thermal Energy Storage
Authors: Vidal Rubén , Saaltink Maarten W
Published: March 2022

Aquifer Thermal Energy Storage (ATES) is a technology that injects heat into aquifers during low energy demand and extracts it during high demand. ATES generates variation of temperature in the underground that can lead to chemical reactions. These reactions can affect the efficiency of ATES and modify the groundwater chemistry and the properties of soils and rocks. We present a novel method that allows calculation of complex numerical models and understanding the thermo-hydro-chemical processes in ATES in a simple way. Aqueous and mineral reactions must be assumed in equilibrium.  The method decouples the chemistry from the thermo-hydraulic processes. The chemical part of the method consists of chemical batch calculations in which minerals dissolve/precipitate and water chemistry varies as a result of changing temperature. The thermo-hydraulic part consists of calculating temperature and spatial and temporal derivatives of temperature. From this, chemical composition of groundwater and precipitation/dissolution rates of minerals can be calculated straightforwardly.

We have applied the method to a HEATSTORE benchmark case, which is inspired by an ATES pilot project located in Bern, Switzerland. We used PHREEQC for the chemical calculations and for the thermo-hydraulic modelling we used the finite element code CODE_BRIGHT. The results permit us to understand better the reactive transport processes in the aquifer (which we divided into mixing, heat retardation and heat conduction), changes in the porosity of the rocks and the precipitation and dissolution of minerals.

 

Acknowledgements: This work was financed by the ERANET project HEATSTORE (170153-4401). This project has been subsidized through the ERANET cofund GEOTHERMICA (Project n. 731117), from the European Commission, RVO (the Netherlands), DETEC (Switzerland), FZJ-PTJ (Germany), ADEME (France), EUDP (Denmark), Rannis (Iceland), VEA (Belgium), FRCT (Portugal), and MINECO (Spain). Also, the first author is supported by a grant from the Department of Research and Universities of the Generalitat de Catalunya (2021 FI_B 00940).
Evaluation of anthropogenic aerosol forcing and multidecadal internal variability contributing to mid-20th century Arctic cooling — CMIP6/DAMIP multimodel analysis
Authors: Aizawa Takuro , Oshima Naga , Yukimoto Seiji
Published: March 2022

In the Arctic, observed decadal mean surface air temperatures (SATs) were 0.70°C–0.95°C lower around 1970 than around 1940. Many of the state-of-the-art climate model in the Coupled Model Intercomparison Project Phase 6 (CMIP6) exhibited Arctic surface cooling trend during 1940–1970, which could be attributed to external forcings. Multimodel means of CMIP6 Detection and Attribution Model Intercomparison Project (DAMIP) historical simulations exhibited Arctic surface cooling of –0.22°C (±0.24°C) in 1970 versus 1940 and showed that anthropogenic aerosol forcing contributed to a cooling of −0.65°C (±0.37°C), which was partially offset by a warming of 0.44°C (±0.22°C) due to well-mixed greenhouse gases. In addition to the anthropogenic aerosol forcings, multidecadal internal variability with a magnitude of 0.47°C was the components primarily contributing to the observed Arctic cooling. The SAT spatial pattern of pan-Arctic multidecadal cooling due to the internal variability was identified by the composite analysis and resembles the obseved Arctic surface cooling pattern during 1940–1970.
Rapid Auroral Wandering During the Laschamps Event
Authors: Mukhopadhyay Agnit , Panovska Sanja , Liemohn Michael , Ganjushkina Natalia , Usoskin Ilya , Balikhin Michael , Welling Daniel , Garcia-Sage Katherine
Published: March 2022

41 thousand years ago, the Laschamps geomagnetic excursion caused Earth’s magnetic field to drastically diminish to ~4% of modern values and modified its dipole-dominated structure. While the impact of this geomagnetic event on environmental factors and human lifestyle has been contemplated to be linked with modifications in the geospace environment, no concerted investigation has been conducted to study this until recently.

We present an initial investigation of the global space environment and related plasma environments during the several phases of the Laschamps event using an advanced multi-model approach. We use recent paleomagnetic field models of this event to study the paleomagnetosphere with help of the global magnetohydrodynamic model BATS-R-US. Here we go beyond a simple dipole approximation but consider a realistic geomagnetic field configuration. The field is used within the global magnetohydrodynamic model BATS-R-US to generate the magnetosphere during discrete epochs spanning the peak of the event. Since solar conditions have remained fairly constant over the last ~100k years, modern estimates of the solar wind were used to drive the model. Finally, plasma pressure and currents generated by BATS-R-US at their inner boundary are used to compute auroral fluxes using a stand-alone version of the MAGNIT model, an adiabatic kinetic model of the aurora.

Our results show that changes in the geomagnetic field, both in strength and the dipole tilt angle, have profound effects on the space environment and the ensuing auroral pattern. Magnetopause distances during the deepest phase of the excursion match previous predictions, while high-resolution mapping of magnetic fields allow close examination of magnetospheric structure for non-dipolar configurations. Temporal progression of the event also exhibits rapid locomotion of the auroral region over ~250 years along with the movement of the geomagnetic poles. Our estimates suggest that the aurora extended further down, with the center of the oval located at near-equatorial latitudes during the peak of the event. While the study does not find evidence of any link between geomagnetic variability and habitability conditions, geographic locations of the auroral oval coincide with early human activity in the Iberian peninsula and South China Sea.
The REYKJANET local seismic network ideally placed for capturing the 2021 Fagradalsfjall pre-eruptive seismicity: in operation since 2013
Authors: Ágústsdóttir Thorbjörg , Horálek Josef , Gudnason Egill Árni , Doubravová Jana , Hersir Gylfi Páll , Klicpera Jakub , Pétursson Fridgeir , Líndal Magnússon Rögnvaldur , Málek Jiri , Fojtíková Lucia , Fischer Tomáš , Vlček Josef , Salama Ali
Published: March 2022

The REYKJANET local seismic network was deployed on the Reykjanes Peninsula, SW Iceland, in 2013; funded by the Czech Academy of Science and supported by Iceland GeoSurvey. The network consists of 15 seismic stations, using Nanometrics Centaur digitizers sampling at a rate of 250 sps with a GPS timestamp. Additionally, 7 stations are equipped with microbarographs. In 2016, REYKJANET was substantially upgraded when short-period seismometers were replaced by Güralp CMG-3ESPC broadband seismometers (eigenperiod T0=30s). The instruments are buried in vaults on concrete pillars and are therefore well coupled with the bedrock. They are powered by batteries recharged by solar and wind power all year round, surviving harsh winter condition and corrosion from geothermal gases. These stations are deployed along the Reykjanes Peninsula, between the Svartsengi and Hengill high temperature geothermal fields, covering an area of about 60x20 km. In the summer of 2021 two new stations were deployed on the eastern part of the Peninsula, each consisting of a Güralp CMG-40T broadband seismometers and a Kinemetrics FBA ES-T EpiSensor also sampling at 250 sps with a GPS timestamp. Since early 2021, data from all REYKJANET stations are streamed in real-time to Iceland GeoSurvey and currently 8 of them are also streamed to the Icelandic Meteorological Office for improved earthquake locations for natural hazard monitoring purposes. Since the deployment of the network in 2013, it has been operated continuously and captured the largest seismic swarms on the Reykjanes Peninsula in 2017, 2019, 2020 and 2021.The REYKJANET network was ideally placed, as the 2021 Fagradalsfjall eruption occurred right in the central part of the network. Here we present the pre-eruptive seismicity of the 2021 Fagradalsfjall eruption in comparison to previous seismic swarms.

The maintenance of REYKJANET, data analysis and interpretation are currently done within the NASPMON project (NAtural Seismicity as a Prospecting and MONitoring tool for geothermal energy extraction), funded through EEA Grants and the Technology Agency of the Czech Republic within the KAPPA Programme.
Process-oriented diagnosis of tropical cyclones based on the moist static energy variance budget in reanalyses and high-resolution climate models
Authors: Wing Allison , Dirkes Caitlin , Camargo Suzana , Kim Daehyun , Moon Yumin
Published: March 2022

Process-oriented diagnostics of tropical cyclones (TCs) facilitate a comparison of models to observations with respect to the physical processes relevant to TCs, informing which processes to target for model improvement. Here we use diagnostics based on the column-integrated moist static energy (MSE) variance budget, which focuses on how convection, moisture, clouds, and related processes are coupled. We use five different reanalysis datasets to provide an 'observation'-based reference against which high-resolution global climate models can be evaluated: ERA-Interim, MERRA-2, CFSR, ERA-5, and JRA-55. We calculate the budget in 10 x 10 degree boxes following tracked TCs composites over storm snapshots of the same intensity. The composites are qualitatively similar to prior work, with radiative feedbacks contributing most to MSE variance growth in the early stages of TC development and in weaker storms, and with surface flux feedbacks increasing strongly with intensity. Reanalyses that have a stronger radiative feedback, normalized by the box-mean MSE variance, in a given intensity bin exhibit a higher percentage of storms that intensify to the next bin, which emphasizes the value of the MSE variance budget as a process-oriented diagnostic for understanding model simulation of TCs. However, there is a large spread in MSE variance and the radiative and surface flux feedback contributions to MSE variance growth across reanalyses, even when considering composites over storms of the same intensity. The spread across reanalyses is comparable to the spread across the high-resolution climate models considered by Wing et al. (2019). This suggests that the data assimilation present in reanalyses does little to constrain the TC-MSE variance budget and indicates that caution must be taken when evaluating climate models against reanalysis. Ongoing work continues to evaluate climate model simulations, including those from the HighResMIP ensemble, against the reanalysis-based reference, and examine the large-scale environments associated with TC formation in reanalyses.
Evaluation of the Effects of Particle Characteristics on the Terminal Settling Velocities of Microplastics in Stagnant Waters using CFD
Authors: Ahmadi Pouyan , Elagami Hassan , Dichgans Franz , Gilfedder Benjamin , Fleckenstein Jan H.
Published: March 2022

Mismanaged waste leads to inputs of microplastics into the environment and the aquatic system affecting rivers and lakes. The physical properties of microplastic (MP) particles affect their terminal settling velocity (TSV) in the water column and in turn their distribution patterns in aquatic systems. To evaluate the settling behavior and the TSV of MP particles we simulated the settling of a large range of MP particles with regular and irregular shapes in the water column using a computational fluid dynamics (CFD) model. To validate the results returned by our model, we compared CFD findings to the corresponding results obtained by semi-empirical relationships as well as the results from experiments for 120 irregularly shaped MP particles with sizes and densities ranging from 500 to 2000 µm and 1.03 to 1.38 grcm-3, respectively. The CFD results are in good agreement with the results from the laboratory and semi-empirical relationships with a 0.05 difference in the slopes of their linear regressions. In a next step, we defined scenarios to systematically investigate the influence of different particle characteristics such as roundness, density, and volume as well as water temperature on the TSV of regular and irregular MP particles. Our simulations revealed a dominant effect of particle density on the TSV compared to the effects of the other parameters. For example, doubling particle densities increased the TSVs of the MP particles up to 500%, while, doubling their volumes only led to a maximum increase in their TSV of 200%. Increasing the roundness of the MP particles, letting them evolve towards a perfect sphere, increased their TSVs by up to 15%, while seasonal changes in lake water temperatures typical for lakes in temperate climate regions, caused changes in TSVs by up to 32%.
Wildfire ash mobilization by run-on under controlled laboratory conditions: Qualitative analysis
Authors: Martins Ricardo , Keizer Jacob , Gama Isa , de Lima Isabel P. , de Lima João L.M.P
Published: March 2022

Globally, high erosion rates are being triggered by extreme rainfall/runoff events. Ashes and char, by-product of devastating wildfires are the first particles mobilized and depleted. The contribution of the ash/char layer to the overall erosion process is still unestablished especially since separating ash and char fraction from litter, soil and eroded sediments is far from trivial. To address this knowledge gap, ASHMOB project (CENTRO-01-0145-FEDER-029351) is studying the mobilization of wildfire ash by wind and water erosion under controlled laboratory conditions as well as field conditions. The present study aims at contributing to the current knowledge on the physical process behind the mobilization of ashes and char when subject to runoff. This research is the second phase of the physical experiments on the mobilization by water of wildfire ash and char, performed at the Laboratory of Hydraulics, Water Resources and Environment of the University of Coimbra. To characterize ash erosion, a multi-channel flume was used (i.e., 5 parallel equal channels), which runs 5 replicate run-on events with exactly the same hydraulic conditions. To collect the full sample, a cart with trays moved at an established and controlled pace under the flumes, allowing the collection of water, ashes and sediments, thus characterising both hydrographs and ash yields for all event and replicate. Temporal resolution was fixed at 20 seconds per tray. Six major variables were tested: (1) Ash depth; (2) Type of burnt vegetation; (3) Ash layer length; (4) Ash particle size; (5) Slope. Preliminary results show that: (1) Smaller ash depths require lower flows to be mobilised by; (2) Pinus pinaster and Eucalyptus globulus have a different behaviour from Arbutus unedo ashes as the former tend to be transported more as a "aggregated block or chunk", possibly due to buoyancy, and the latter more like sediments; It was also observed that a higher number of large particles of char tend to provide a somewhat larger protection to the finer ashes than having little or no large particles of char; (3) a longer, in the flow direction,  layer of Arbutus unedo ashes has little to no impact in the mobilisation process, whereas for the other vegetations, a longer layer implies less transport relative to the initial amount of ashes; (4) smaller particle sizes, when left without the "protection" of larger char particles are transported more easily; (5) Slope has a large impact on the transport of ashes, especially when considering the same bed roughness.
Understanding ENSO related tropical teleconnections using Quasi-equilibrium tropical circulation model
Authors: Suresan Sohan , Joseph Mani Neena
Published: March 2022

Atmospheric teleconnections are remote impacts associated with atmospheric processes transmitted through planetary-scale waves like the Rossby wave. Tropical heat sources like El Nino Southern Oscillation (ENSO) could force such planetary-scale wave responses. The El Nino events are classified into Non-OLR El Nino events and OLR El Nino events based on its convective signal over the central-eastern equatorial Pacific using an OLR based El Nino Index. The key purpose of this study is to analyse the difference in teleconnection patterns during these OLR based El Nino events and understand its baroclinic-to-barotropic mode responses using an intermediate complexity atmospheric circulation model called Quasi-equilibrium tropical circulation model (QTCM). The study analyses the difference in the distribution of atmospheric variables and Rossby wave source (RWS) anomalies during Non OLR El Nino events and OLR El Nino using QTCM experiments. It is seen that the OLR El Nino events have a larger barotropic contribution to the positive anomaly of SLP over the western Pacific and a larger baroclinic contribution to the negative anomaly of SLP over the eastern Pacific compared to Non-OLR El Nino events. This is due to stronger baroclinic Rossby waves from the eastern and central tropical Pacific that propagates towards western Pacific and force barotropic wave trains due to barotropic-baroclinic interactions. Also, on analysing the effective RWS forcing and its components over certain regions during OLR and Non OLR El Nino, we see a difference in their distribution due to contributions from the absolute vorticity advection by divergent wind flow and subtropics vortex stretching. We further investigates the baroclinic-to-barotropic interaction over the midlatitude and tropical teleconnection through baroclinic-barotropic interaction terms in barotropic Rossby wave during Non OLR El Nino and OLR El Nino. It was seen that among the barotropic Rossby wave source interaction terms, the shear advection term has the largest contribution and the mean baroclinic zonal wind that advects the baroclinic zonal wind anomaly due to tropospheric heating is the most relevant component. The effective RWS over the tropics and the subtropics arise from the mean state baroclinic flow that acts on the baroclinic wind structure arising due to the ENSO tropospheric heating that spreads over a scale of equatorial radius of deformation from the deep tropics to the subtropics. This baroclinic wind structure is stronger for OLR El Nino compared to Non OLR El Nino. The experiment is also extended to preindustrial and mid-Holocene periods using data from CESM. The mid-Holocene OLR El Nino has a weaker RWS response than the preindustrial OLR El Nino due to the relatively weaker tropospheric heating and temperature structure, resulting in a weaker baroclinic wind structure.
The late Eifelian (Middle Devonian) Kačák event and its effects on rugose coral palaeobiodiversity (Ardennes, Belgium)
Authors: Jamart Valentin , Denayer Julien
Published: March 2022

Of the many biocrises that occurred during the Devonian period, the most studied ones are the end-Devonian Kelwasser event (Frasnian-Famennian Boundary) and the Hangenberg event (Devonian-Carboniferous Boundary). However, the Middle Devonian crisis are receiving an increasing attention. The crisis occurring immediately before the Eifelian-Givetian Boundary (ensensis conodont zone) is known as the Kačák event. It has essentially been identified by time-specific lithofacies in deep-environment settings where pelagic faunas (conodonts, ammonoids, dacryoconaridids) suffered extinctions. On the Belgian neritic carbonate shelf system the Kačák event has been identified, in the lower part of the Hanonet Formation where a complex faunal turnover took place but with few changes in the depositional settings as known in deeper environments. The event is also recognised on a palaeobiological base as the pre-crisis Old World Realm fauna-dominated assemblages are suddenly facing the invasion of East American Realm fauna such as siphonophrentid and heliophillid rugose corals. After the crisis, these corals are very uncommon and the Old World Realm assemblages become largely dominant again. This palaeobiological criterion is proposed to help, especially when the typical pelagic guides are missing, in the identification of the Kačák event.
Linking the carbon and sulfur cycles in a historically brackish diked peatland: Stable Isotopes and FT-ICR-MS
Authors: Zeller Mary , von Ahn Cátia , Jenner Anna-Kathrina , Racasa Erwin , McKenna Amy , Janssen Manon , Böttcher Michael
Published: March 2022

Here we report on the porewater dissolved organic matter dynamics and underlying benthic biogeochemical processes in a historically brackish, diked, peatland located along the Baltic Sea in northeastern Germany.  The regeneration process of the “Heiligensee and Hütelmoor” includes a return of freshwater inputs as well as increased connection to the sea.  For porewater observations, two stationary multiport (about 0.5 m intervals) lances are located in the coastal sediments coastward of the sand-dune dyke, reaching down to ~5 meters through permeable sediments and peat layers.  Frequent sampling of these porewater lances indicates substantial influences by fresh submarine ground water discharge in the middle depths.  Therefore, we studied the impact by mixing of these groundwater (as, for example, a source of Fe, DOM, DIC, P, Ca) with saltwater (a source of SO4 to fuel sulfate reduction) and the role of organic matter in the drowned peat layers.  We were particularly interested in the sulfurization of DOM, as biogenic sulfide can react both with Fe and DOM/POM.  Samples for a suite of analyses were taken in November 2020.  Characterizations included dissolved organic matter (21T FT-ICR-MS, National High Magnetic Field Laboratory), major and trace elements (ICP-OES), nutrient and sulfide concentration, as well as stable isotopes of sulfate, DIC, and water. Results are compared to nearby groundwater wells (a coastal sandy aquifer, a coastal peat layer, and an inland well), the brackish Baltic Sea and  the Hütelmoor surface waters, as well as the river Warnow.  Thus, we characterize the endmembers as well as the mixing zones in order to understand their influence on the chemical alterations of dissolved organic matter in this dynamic region.
Short-term dynamics of Sermeq Kujalleq in Kangia (Jakobshavn Isbræ), Greenland derived from TRI and GNSS measurements
Authors: Wehrlé Adrien , Lüthi Martin P , Nap Ana , Jouvet Guillaume , Walter Fabian
Published: March 2022

Sermeq Kujalleq in Kangia (Jakobshavn Isbræ), Greenland has been extensively investigated over the past decades due to its recent retreat associated with extremely fast ice stream flow and high solid ice discharge. However, its short-term dynamics still remain poorly understood as they consist in transient states that can only be captured by high spatial and temporal in situ measurements. In the new COEBELI project, we aim at combining high resolution field data sets from seismic arrays, global navigation satellite system (GNSS) receivers, long-range uncrewed aerial vehicles and terrestrial radar interferometers (TRI) to achieve a comprehensive and detailed study of the short-term ice stream dynamics. Here, we present TRI and GNSS retrievals of surface velocity and elevation acquired during the first, exploratory field campaign of the COEBELI project in summer 2021. Seven kilometers away from the calving front, we specifically identified a slowdown of 1.12 m d-1 within a single day in the main trunk of the ice stream. While the absolute slowdown is larger in the main trunk than in the outer area of the shear margin (1.12 m d-1 versus 0.75 m d-1), it corresponds to a larger fraction of the pre-slowdown velocity in the latter zone (-4.48% versus -7.94%). We further discuss the challenges associated with the acquisition, processing and analysis of high-resolution data sets for the study of such complex and dynamic environments.
Cartographic Retrospective of spatial and temporal changes of gardens and parks in Tbilisi
Authors: Kharebava Nino , Nikolaishvili Dali , Tsitsagi Mariam
Published: March 2022

Growth and development of the city lead to a drastic change in the natural environment, which causes a lot of environmental problems. Among the problems is the reduction and destruction of green cover. In Georgian cities, green cover can be found in two primary forms: natural habitats (which is currently very rare) and gardens (artificially cultivated, often for decorative purposes) and parks (synthesis of vegetation and entertainment attractions, which is a relatively latter form). The capital, Tbilisi, is an ancient city, and therefore it has gone through several stages of urban development, which logically led to the reduction of green space. The research aims to systematically map space and time changes in gardens and parks in Tbilisi. A geodatabase was created based on historical narrative sources, ancient maps, city plans, and satellite imagery in Arcmap 10.8, based on which a retrospective spatial analysis of gardens and parks in Tbilisi was performed. First, gardens and parks were identified; their location, area, vegetation types, changes, and primary drivers were determined and analyzed. The maps of Tbilisi from the 18th, 19th, and 20th centuries were used as a cartographic basis. They are compiled into different scales and projections. All the maps were georeferenced, and the gardens given in the historical sources are identified. In addition, Soviet topographic maps and satellite imagery (CORONA and aerial photography) were used to reconstruct the changes that took place in the 20th century. Based on the obtained results, it turns out that gardening was quite developed in Tbilisi in the Middle Ages. Mostly, oriental style gardens predominated. There were two main directions: publicly available gardens in the city area and gardens arranged around the noble palaces. In this case, in addition to local varieties (mostly broadleaf), varieties imported from different countries were also used. The city's green cover has been declining since the 19th century amid rapid urbanization. The replacement of gardens in the city with built-up areas begins. In the first half of the 20th century, coniferous plants (mostly pine) were planted intensively, and coniferous vegetation became the dominant type in gardens or parks (later). Since the second half of the 20th century, a new type of recreational places appeared- the park. It is a kind of synthesis, where attractions, open-air cafes, and children's spaces are arranged with a green cover. Arranging such parks was part of Tbilisi's master plans. Amid the complex social, political, and economic situation in the country since the 1990s, small parks have begun to disappear amid uncontrolled urban sprawl, compounded by the massive decline of coniferous vegetation in the face of the city's climate change (urban heat island) or/and parasites. Recently, the restoration of gardens and parks has become particularly active. It is part of the city’s new General plan.
Fractional snow cover estimation through linear spectral unmixing of Sentinel-2 and Sentinel-3 optical satellite data using local endmembers
Authors: Keuris Lars , Nagler Thomas , Mölg Nico , Scheiblauer Stefan
Published: March 2022

Precise snow cover estimations are relevant for many fields of research applications, such as for hydrological and meteorological modelling. Furthermore, snow plays an important role in hydropower management and flood prediction. Snow cover monitoring from satellite imagery has received increasing attention over the past decades. Nowadays, improvements in estimation methodologies and better availability of augmented satellite imagery provide an excellent basis for reliable estimations of fractional snow cover.

In this work we exploit the available spectral information of the Sentinel-2 MSI and Sentinel-3 OLCI for automatic estimation of fractional snow coverage. This is achieved through linear spectral unmixing with local endmembers. Similar implementation of methods that employ spectral unmixing use a reflectance model or a spectral library with pre-selected endmembers. Our approach selects the spectral endmembers from the data itself and applies them depending on the distance from the query point assuming spectral similarities of ground reflectance nearby. Endmembers are found through a pre-classification step based on conservative thresholds in combination with a similarity measure. The linear unmixing problem is solved several times for each query point using different combinations of endmembers detected in the vicinity of the query point; accounting for different illumination conditions and shaded areas. Finally, a careful selection of accurate fractional snow cover estimations is performed. This approach is globally applicable, adjusts to the local environment and illumination conditions and avoids costly endmember modelling or the provision of an external spectral library. The method was tested in different regions in the world using different satellite data including Sentinel-2, Landsat and Sentinel-3 OLCI and were inter-compared with snow information from other sources. In the presentation we will present the method, and examples of fractional snow cover maps. The performance of the method will be shown in comparison with other data and the limitations and capabilities will be discussed.
Flux Transfer Events in the Northern Hemisphere Polar Cusp Under Strong IMF Bx
Authors: Doherty Caoimhe , Fazakerley Andrew , Owen Christopher , Fear Robert , Forsyth Colin , Kavanagh Andrew , Trattner Karl-Heinz , Bogdanova Yulia
Published: March 2022

The location, shape, and size of the magnetospheric polar cusps are heavily influenced by upstream solar wind conditions. The effects of dominant IMF Bz and By components on the cusp are now well known.  However, the effect of a strong IMF Bx component on the structure of the polar cusps is relatively unexplored.  We present a case study of data recorded by the four Cluster spacecraft during a crossing of the northern hemisphere high altitude cusp in the winter season of 2018, when the IMF is directed southward and sunward. The Cluster spacecraft traverse the high-altitude cusp with separations between several hundred km and 1.5 Earth radii between each spacecraft, and travel at a roughly constant latitude with changing MLT.  We study these observations in conjunction with those of the ground based SuperDARN radars.

Each spacecraft observes many flux transfer type events within the cusp, although some events are not seen on all 4 spacecraft.  The magnetic field orientation often varies significantly during each distinct passage through individual flux tubes, clearly departing from the background magnetic field direction expected in the northern hemisphere high altitude cusp. A number of these events show bidirectional electron flux signatures typical of those expected on recently reconnected open northern hemisphere flux tubes. However, some flux tubes appear to be populated only by antiparallel moving electrons, while others show an isotropic distribution of electrons and ions. The SuperDARN STO radar site observes Poleward Moving Auroral Forms (PMAFs), consistent with the interpretation that Cluster observes open flux tubes, however the directions of convecting flux tubes seen by Cluster are not always consistent with the SuperDARN picture. We consider whether the influence of the strong IMF Bx results in the relocation of the dayside reconnection site to high northern latitudes, allowing Cluster to encounter a mix of open flux tubes in the northern cusp, each of which may be connected to either the Northern or Southern polar ionosphere.  The latter configuration may be particularly supported if reconnection near the cusp results in southern hemisphere open field lines being driven anti-sunward into the northern cusp as a result of enhanced sheath flows overcoming their magnetic tension at these latitudes.
3D pathways and distribution of microplastics in the Ocean Surface Boundary Layer
Authors: Zazzini Simone , Pini Agnese , Bello Paolo , Monti Paolo , Leuzzi Giovanni
Published: March 2022

Microplastic (MP) in the ocean is a major environmental problem. Better understanding of how MP, released from anthropogenic sources, is transported is crucial to quantify and close the global inventory of marine MP. At the same time, neutrally buoyant MP can be considered as a passive tracer that provides the opportunity to learn more about the turbulent dynamics of the ocean across multiple scales.

This work explores the turbulent dispersion of MP with a 3D Lagrangian stochastic model, developed by the authors, with particular attention on the Ocean Surface Boundary Layer (OSBL).

The inputs of the model are operational oceanographic data, downloaded from the Copernicus Marine Monitoring Environment Service, such as current velocities, mixed layer depth and friction velocity. The simulated trajectories are described by a Wiener process in which the vertical turbulent diffusivity is parameterized with a novel method developed by the authors. The advantage of the Lagrangian approach is to reproduce turbulent dispersion processes at sub-grid scales.

A 10-year 3D simulation of the MP dispersion in the Mediterranean basin has been performed.  MP pathways and accumulation zones in different periods of the year have been identified.

The distribution of MP in the water column has been obtained. The behavior of different polymers has been investigated showing that particle settling prevails with respect to vertical turbulent dispersion. Despite the concentration of particles is maximum at the sea surface, the quantity spread into the water column is not negligible.
Cervest as the provider of Climate Intelligence: learnings from our users, collaborations with academics
Authors: Zamboni Laura , White John
Published: March 2022

We've reached an inflection point in our relationship with the climate. Accelerating climate volatility is threatening the assets we rely on. To adapt, we need to be smarter, more prescient, more decisive, and more collaborative than ever before. We need new instruments and new insights. We need what we call Climate Intelligence.

 

Cervest creates Climate Intelligence for every person, asset, and decision. Climate Intelligence transforms how we build, manage, and de-risk our most valuable assets. Climate Intelligence enables us to adapt and decarbonize at scale to build an equitable and resilient future for our planet.

 

Cervest is at a turning point: we have concluded the first round of development whereby the initial offerings our scientists developed have been explored by major enterprises worldwide and incorporated in their decisions and reporting. A co-creation phase has been part of the process whereby we elicited users’ feedbacks. Learnings from this phase both confirmed some of our expectations and revealed needs we had not fully appreciated, many of which are leading to the deepening of our market education efforts as well as scientific-product developments. 

 

We find that to proactively adapt and decarbonize, it is essential to establish fruitful collaborations among different actors, and more specifically between Cervest and publicly funded institutions. It is within such collaborations that a swift exchange of information, data and expertise clarifies roles and responsibilities, ultimately accelerating our common drive to support adaptation and mitigation. 

We will share the lessons we have learned and, following the conveners’ call, our view of what is desirable from the public sector, ultimately engaging with academics.