bluuebunny/crossref_metadata_2025 huggingface dataset:
Accounting for the NAO when applying observational constraints to future European climate projections
Authors: Ballinger Andrew , Schurer Andrew , Hegerl Gabriele
Published: March 2022

The North Atlantic Oscillation (NAO) is the leading mode of climate variability over the North Atlantic region, affecting temperature and rainfall over timescales from days through to seasons and decades. Previous studies have shown that variations in the NAO yield significant multi-decadal trends in European rainfall, especially in winter, and the magnitude of past multi-decadal NAO variability is generally not reproduced by CMIP class models This has important implications for deriving observational constraints, and the application of these scaling factors to projections of future European rainfall.

We have constructed two sets of multi-model-mean spatiotemporal fingerprints of European rainfall: one set that retains NAO variability, and another set that excludes the variability associated with the NAO (removing it using a simple regression technique). Following the so-called Allen-Scott-Kettleborough ‘ASK’ method, we conduct total-least-squares regressions using the two different sets of fingerprints against the observations in order to analyse the impact of removing the NAO in potentially enhancing the signal-to-noise. The derived scaling factors shed light on the ability of CMIP6 models to reproduce the magnitude of the forced response in precipitation, and confidence intervals for each of the scaling factors describes the range of magnitudes of the model response that are consistent with the observed signal.

Here we focus on one clear example, northern European rainfall, although we have also analysed additional European regions and surface air temperature across all of the seasons. There is an increasing trend in observed rainfall anomalies associated with the NAO over northern Europe, most pronounced in winter, which is not replicated in models. Once the variability associated with the NAO is removed the magnitude of the observed trends is reduced, and the scaling factors (derived in the ASK framework) are similarly reduced.

Along with a shift in the magnitude that comes from the modified observations, the constraint also tightens (the spread in consistent scaling factors narrows) due to the increased signal-to-noise in the modelled response once the NAO is removed from the simulations. This has important implications for the use of scaling factors to constrain future projections of European climate. The observed decadal to multi-decadal trends resulting from known modes of internal variability should be accounted for in the derivation of scaling factors to better capture the forced signal and bolster confidence in the constrained projections.
Automatic Detection and Location method of Tremor signals: A case study from East Java, Indonesia.
Authors: Díaz Sergio , Maupin Valerie , Mazzini Adriano , Minetto Riccardo , Lupi Matteo , Karyono Karyono
Published: March 2022

Mount Bromo is an andesitic stratovolcano in East Java, Indonesia, that entered into unrest between November 2015 and January 2016. The seismic activity was captured by the permanent seismic stations of the Indonesian seismological service (BMKG) and by a temporary (GIPP-provided) network deployed in the framework of the LusiLab Erc project. The goal of the temporary network deployed was to study the seismic signature of the newborn sediment-hosted geothermal system nicknamed LUSI. A preliminar inspection of the dataset showed that the activity of Bromo may have been recorded by stations of the temporary network. To investigate this further, we attempt an automatic detection and location of the impulsive and emergent signals recorded during Bromo’s eruption. We use the Recursive STA/LTA on each component of the stations and apply a coincidence trigger to adjust the pickings aside with a first-arrival validation through a polarization analysis. A total of 32.787 events were detected, and some of these are consistent with variations in the eruptive activity observed at Mt. Bromo. The accepted locations (RMS ≤ 1; 3.965 events) revealed multiple superficial sources, concentrated between 0 and 5 Km depth, originating from Mt. Bromo and 4 other main volcanic structures located in the surrounding region. Other sources were localized at greater depth, between 10 to 50 Km, and are attributed mainly to interactions between the magmatic chambers of the volcanoes, and movements in pre-existing sutures zones (faults) from overpressure of magmatic activity. Chronologically, a peak preceding the main eruption was found, characterized by an increase in Volcano-Tectonic-type (VT) signals beneath Mt. Bromo. This is consistent with other cases observed at similar strombolian-type volcanoes prior to eruptions. After an assessment of the automatic processing procedure used, we suggest improvements for future works by: 1) applying an association method based on the same principle as the coincidence trigger used in the detection step, and 2) using the polarization analysis in a sliding window along the event signal to re-pick the first-arrivals.
Solar Orbiter SWA-PAS and SWA-HIS observations of O+ ions in the very distant tails of the comets C/2019 Y4(ATLAS) and C/2021 A1(Leonard)
Authors: Fedorov Andrey , Livi Stefano , Louarn Philippe , Owen Chris , Raines Jim
Published: March 2022

ESA solar observatory Solar Orbiter is expected to have flown close to a comet plasma tail two times during the mission cruise phase. It passed behind the comet C/2019 Y4(ATLAS) in the end of May 2020. The second chance occurred on December 2021 when Solar Orbiter has encountered the tail of C/2021 A1(Leonard). In the both cases the distance between the spacecraft and the comet nucleus was about 40 million km. At the time of the encounter the comet ATLAS was at just 0.3 AU from Sun, and in the second case the comet Leonard was at the Venus orbit (0.7 AU). In both cases SWA-PAS ion spectrometer has seen very clear signature of the pickup O+ ions (with the maximum at about solar wind velocity). We observed the flow of the cometary tail ions as rather sharp bursts on just several minutes of duration. The heavy ion mass-spectrometer HIS observed O+ ions (among other species of the cometary origin) during the Leonard's tail encounter. We used inter-calibrated data of both instruments to get the absolute O+ flux from both comets.
Vertical distribution and aerobic degradation at the sediment-water interface in two urbans estuaries in Normandy, France
Authors: El Houssainy Amonda , Poirier Isabelle , Bertrand Martine , Verdier Laure , Cesbron Florian
Published: March 2022

In the current context of climate change, the coastal area is exposed to an increasing pressure from hydrodynamic agents such as tide, flood and storm (Parry et al., 2007) and to enormous anthropogenic activities due to urbanization and industrialization of the coastline, which weakens the coastal ecosystem. In France, the Manche department presents more than a half of the Normandy coastline (330 km) and a great diversity of its shores. It is a key player in the preservation of the coastal environment. Among its conservation areas, two estuaries in Saint-Vaast-La-Hougue interested us: the Saire Estuary and Cul-de-Loup Bay, which both subjects to the impact of human activities (agriculture, shellfish farming, tourism, modification of the coastline, etc.). In order to quantify the chemical and biological exchanges in the mudflat of these two sites, we performed dissolved oxygen profiles in the sediment using a benthic microprofiler system (Unisense®). Moreover, sediment cores were collected and sliced under inert atmosphere, in order to measure diagenetic tracers (NH4+, PO43-, Fe2+ and ΣHS-) and trace metals levels, and to identify bacterial communities. The results of sediment cores and oxygen microprofiles taken from each of the mudflat indicate a greater dynamic degradation of organic matter in the superficial sediments of Saire estuary and in deep sediment of Cul-de-Loup Bay. The benthic microprofiler results show that oxygen penetration depth is around 1 mm and 1.4 mm respectively in Saire estuary (n=3) and Cul-de-Loup bay (n=5). This difference is marked by (i) an intense reduction of Fe (oxy)hydroxides at 4 cm of sediment depth in the Saire estuary, (ii) the appearance of ΣHS- from ~ 12 cm of sediment depth against 5 cm of sediment depth in the Cul-de-Loup Bay and (iii) a slight Fe(oxy)hydroxide zone at 3 cm of sediment depth. Metagenomics analysis confirm major differences between the two study sites.
Assessment of a short-term machine learning streamflow forecasting in small Alpine catchments leveraging Deutscher Wetterdienst ICON climate forecasting model
Authors: Dalla Torre Daniele , Menapace Andrea , Zanfei Ariele , Righetti Maurizio
Published: March 2022

Data-driven methods are widely adopted to forecast short-term streamflow with lead time up to a few days. Flood risk mitigation, multi-use water management and hydropower plants schedule are the most common fields to use forecasting results. Increasing the accuracy and limiting the uncertainty of the predictions are common needs and also this work would evaluates these aspects combining regional climate models and machine learning techniques. Thus, the research question addressed regards the suitability of the machine learning algorithm fed by the ICON forecasting regional climate model for short lead time streamflow prediction in a small and complex Alpine environment.

A data-driven forecasting procedure is used for streamflow forecasting on a lead time of two days in small Alpine catchments of the Alto Adige Province (Italy). Bias correction of the ICON prediction data inputs against the historical data and the machine learning module compose the two steps data-driven methodology that we propose. Historical time series of precipitation and temperature provided by weather stations have been used for training the machine learning algorithms, while the ICON prediction data of precipitation and temperature have been adopted for testing them. The use of historical data has been essential for collecting a reasonable amount of data required for algorithm learning. The methodology performance evaluation is on the meteorological correction and on the hydrological forecasting.

This first assessment shows promising results for two-day head streamflow prediction even in the context of small catchments with complex orography. This finding suggests that the merging of robust data-driven methodologies with high-resolution detailed weather prevision inputs can be a consistent breakthrough for reliable hydrological short-term forecasting. In conclusion, the flexibility of machine learning and ensemble climate prediction allows for adequate management of uncertainty along the prediction procedure, which is crucial in hydrological applications.
Selection of Macrodispersivities Values in Models of Aquifer Contaminant Transport: A Practitioners Perspective 
Authors: Teutsch Georg , Zech Alraune , Attinger Sabine , Bellin Alberto , Cvetkovic Vladimir , Dagan Gedeon , Dietrich Peter , Fiori Aldo
Published: March 2022

Selection of Macrodispersivities Values in Models of Aquifer Contaminant Transport: A Practitioners Perspective

Alraune Zech, Sabine Attinger, Alberto Bellin, Vladimir Cvetkovic, Gedeon Dagan, Peter Dietrich, Aldo Fiori and Georg Teutsch

ABSTRACT

The spreading of contaminants in groundwater is dominated by the spatial variability of the hydraulic conductivity K. Solutes are practically immobilized in zones of low K while they move quickly through high K paths. The field rates of spreading are much larger than the ones observed in laboratory as quantified by the pore-scale dispersivities. It is common to model transport by an Advection-Dispersion Equation with macrodispersivities (longitudinal, transverse, vertical) to quantify the enhanced effect of heterogeneity. Macrodispersivities are aquifer specific and selecting their values require characterization of K structure by elaborate field data collection and analysis. In many applications, particularly for preliminary assessment of contaminant transport, such data are not available and macrodispersivities  are selected in a quite arbitrary manner e.g. by using the “universal” scale dependence. We have shown in the past by a thorough analysis of field data that such a choice is erroneous and may lead to prediction of unrealistically large rates of spreading.

We propose a methodology to select macrodispersivities values for preliminary assessments by defining 3 classes of aquifer heterogeneity (low, medium, high). Based on analysis of a large number of field data we recommend for each class a range of macrodispersivities values. The selection of the class for a particular aquifer is based on estimates of the value of logconductivity variance when available or on geological information regarding the proportions of aquifer material fractions. While of an approximate nature it is surmised that the methodology leads to more realistic macrodispersivities values than existing empirical rules.
Retention of radionuclides in a fracture infill
Authors: Jankovský Filip , Kočan Karol , Hofmanová Eva , Havlová Václava , Zuna Milan , Smutek Jan
Published: March 2022

The EURAD European Joint Project (www.ejp-eurad.eu) is a European project supported by the European Commission via the Horizon 2020 framework programme. WP 5: Fundamental understanding of radionuclide retention (FUTURE) concerns the quantification of the long-term retention of key radionuclides in solid phases aimed at developing models of reactive transport in the host rock in close cooperation with the Development and improvement of numerical methods (DONUT) WP. The Mobility of radionuclides in crystalline rock Task of the WP is aimed at the observation of the retention of DGR-relevant radionuclides in a crystalline host rock fracture filling and the evaluation of its contribution to the safety function of the crystalline host rock. A calcite fracture filling, nickel as the radionuclide of interest and caesium as the reference radionuclide were selected so as to allow for the study of sorption processes in the crystalline fracture environment. Samples of a natural calcite fissure infill and migmatite host rock extracted from the Bukov URF, Czech Republic, were distributed to the various project partners for experimental research purposes. Batch sorption experiments were subsequently performed on both materials using Ni, Cs and other elements in synthetic ground water and CaCl2 for the calcite. The results of Ni sorption on natural calcite revealed a lower level of retention than that of the surrounding host rock (migmatite).
Investigating the environmental impact of Shallow Geothermal Energy systems across Europe
Authors: Aresti Lazaros , Christodoulides Paul , Makarounas Christos , Florides Georgios
Published: March 2022

Geothermal energy finds application with Shallow Geothermal Energy (SGE) systems for space heating and cooling. Ground Source Heap Pumps (GSHPs) constitute the main systems used in SGE when coupled with Ground Heat Exchangers (GHEs). GHEs are essentially a network of tubes that extract or reject heat to and from the ground. GSHP systems have recently gained more attention and are recruited for the reduction of fossil fuels and CO2, as an alternative to Air Source Heat Pump (ASHP) systems. However, recent advancements of the ASHP systems through the improvement of their coefficient of performance (COP) classify these at a very competitive scale against GSHP systems.

The directive of the European Union (EU) on the nearly Zero Energy Buildings (nZEB) is already in effect, and requires the residential buildings to have better insulation on the building’s envelop, leading to a reduced heating and cooling demand. Such cases could further weaken the higher energy performance of GSHPs and make these systems a not so attractive alternative compared to ASHP systems. 

This research aims to investigate such scenarios using seven case studies, at seven different locations across Europe. The same residential building is used in all cases with nZEB technical characteristics. To this extent, a Life Cycle Analysis (LCA) is performed for the environmental evaluation using the ReCipe impact method from a midpoint perspective. The openLCA software is considered, coupled with the Ecoinvent 3.6 dataset for the impact methods and databases. A comparison is made of the case studies through an analysis of the global warming potential impact category. The results show that the northern European countries exhibit a better comparison performance between the ASHP and GSHP systems, compared to the southern European countries.
SOM-based circulation types in the Mediterranean basin from reanalysis and CMIP6 models
Authors: Philippopoulos Kostas , Tzanis Chris , Cartalis Constantinos , Blougouras George , Agathangelidis Ilias
Published: March 2022

The aim of this work is to produce a climate atmospheric circulation classification via Self-Organizing Maps (SOM) and to identify and evaluate the respective changes in the frequency of the identified regimes for GCM projections (Coupled Model Intercomparison Project phase 6, CMIP6). The main focus is to assess the ability to accurately represent the large-scale circulation over the Mediterranean and to generate atmospheric circulation regimes that can be used as an explanatory tool in multiple research fields. The classification framework uses an unsupervised learning algorithm for a low-dimensional representation of high-dimensional datasets (SOM) to identify non-linear relationships and patterns from complex spatiotemporal climatological fields. Upon the selection of the atmospheric variables and the corresponding spatial and temporal scales, the SOM framework will be applied initially to the historical period climate series of large-scale atmospheric circulation from reanalysis datasets and following to a multi-model ensemble of GCM simulations for multiple Socioeconomic Pathways (SSPs). The resulting atmospheric circulation regime catalogs will be compared and discussed in terms of the representativeness of the large-scale circulation by the GCM climate models for the Mediterranean domain. The catalogs will assess the corresponding changes in atmospheric circulation, focusing on the regimes’ frequency of occurrence, persistence, and transition probabilities
Phases of peatland carbon accumulation in the southern mid-latitudes
Authors: Thomas Zoë , Cadd Haidee , Turney Chris , Haines Heather , Marjo Chris , Becerra Valdivia Lorena , Carter Steffi , Brickle Paul
Published: March 2022

Creating high resolution chronologies in sediment sequences is important for understanding past carbon-climate dynamics, including accurately dating the timing of climate events, and calculating carbon accumulation changes through time. Here we present >100 14C dates from UNSWs high-throughput MICADAS (Turney et al. 2021) that help answer key questions about carbon-climate dynamics in the Southern Hemisphere. Peatlands from the southern mid-high latitudes have an important role in the global carbon budget but are underrepresented in global syntheses due to paucity of data. Developing accurate age-depth models from peat sequences is notoriously difficult. Outliers are common, with peat being susceptible to issues such as root penetration and in-wash of sediment. With careful consideration to site selection (Thomas et al. 2019) and material preparation (e.g. sieving out root and rootlet material), the age-depth models presented here demonstrate stratigraphic integrity with no evidence of significant outliers, providing robust and detailed chronologies to enable a range of scientific questions to be answered.

To better constrain the understanding of southern peatland dynamics, we collected and radiocarbon-dated 25 basal peats from across sub-Antarctic islands of the South Atlantic region, doubling the existing available data. We then collated basal peat radiocarbon ages from >35°S and analysed their temporal and spatial distribution. We find two distinct phases of peat formation, at ~16,000 cal years BP and ~13,000 cal years BP, independent of northern hemisphere peat growth. Well-constrained age models from these regions (including a 6 m peat sequence with 55 14C dates) show changes in carbon accumulation rates that are consistent with these phases. Potential drivers of these phases include growth disruption via the Antarctic Cold Reversal, and the latitudinal movement of the southern hemisphere westerly winds, with implications for future carbon storage in these under-studied regions.

 

References

Thomas, Z.A., Turney, C.S.M., Hogg, A., Williams, A.N., Fogwill, C.J., 2019. Investigating Subantarctic 14 C Ages of Different Peat Components: Site and Sample Selection for Developing Robust Age Models in Dynamic Landscapes. Radiocarbon 61, 1–19. doi:10.1017/rdc.2019.54

Turney, C., Becerra-Valdivia, L., Sookdeo, A., Thomas, Z.A., Palmer, J., Haines, H.A., Cadd, H., Wacker, L., Baker, A., Anderson, M., Jacobsen, G., Meredith, K., Chinu, K., Bollhalder, S., Marjo, C., 2021. Radiocarbon protocols and first intercomparison results from the Chronos 14Carbon-Cycle Facility, University of New South Wales, Sydney, Australia. Radiocarbon 63(3), 1003–1023. doi:10.1017/RDC.2021.23
Learning from differing errors between machine learning and a conceptual hydrological model - the case of convective storms and flash floods
Authors: Meyer Judith , Loritz Ralf , Pfister Laurent , Zehe Erwin
Published: March 2022

In recent years, major floods triggered by convective events during the summer months repeatedly occurred in central western Europe, where flood regimes had previously been characterised by slowly developing inundations in winter. This imposes a great challenge on conceptual hydrological models, as other runoff mechanisms seem to dominate during convective storms than the storage-driven runoff production, which dominates flood formation in the wet season. Hence, most hydrological models that are used for operational flood forecasting struggle when applied to convective events and show deficiencies in capturing peak flows and timing flood volumes. It is thereby unclear to which extent the uncertainty in precipitation input and discharge observations, the influence of the catchment state, the model structure itself, or a combination of several or all of these factors, compromise successful predictions. To shed light on this question, we will compare how different model structures perform during high flows across a range of catchment physiographic settings. We will analyse the performance of a conceptual hydrological water balance model and identify its deficiencies by comparing it to a data driven model. This comparison will reveal whether uncertainties in the input and output data or model structural deficiencies are the major source of error. This will allow us to identify systematic errors, compare them and improve the model structure.
The distribution and abundance of microplastics in the waters and organisms of the River Thames, UK.
Authors: Andrews Stephanie , Lewis Ceri , Galloway Tamara
Published: March 2022

A ubiquitous contaminant across the globe, microplastic contamination is a growing issue of which the effects and consequences in the environment are relatively unknown. Freshwater systems, specifically rivers, are important in the translocation of microplastics from terrestrial sources to the marine environment. This makes it vital to understand the abundance and distribution of plastics within them and any potential effects on freshwater organisms. The River Thames is the second largest river in the UK and has multiple anthropogenic stressors and pathways of potential microplastic contamination along its trajectory. This study aims to determine the distribution and abundance of microplastics in the waters and benthic organisms that inhabit the River Thames. It will explore how location and proximity to sites of potential contamination, and feeding type influence the ingestion of microplastics in organisms. Water samples were collected from the river in May 2019 along with benthic dwelling organisms from 3 sites of suspected microplastic contamination. Initial findings reveal a high abundance of microplastics in water samples from the River Thames (average 3.55 mp/m3) and abundance increases along the trajectory of the river (1.05 mp/m3 at the highest sampling site increasing to 5.72 mp/m3 at the lowest sampling site). In all sites sampled, fragments and fibres were the most dominant particle shapes. Filter feeders ingested the highest abundance of microplastic fibres whilst grazers had the highest abundance of ingested fragments. The abundance of particles ingested by invertebrates differed across study sites showing varying levels of contamination. The presence of microplastics in a range of benthic taxa aligned with differences in dominant particle shapes in species with distinct feeding modes indicates widespread contamination with potential ecological impacts of microplastics in freshwater species of the River Thames.
Spatiotemporal post-fire change analysis using optical and SAR imagery
Authors: Lee Yeji , Oh Junse , Kim Su Young , Jung Yoon Taek , Park Sang-Eun
Published: March 2022

Wildfires on permafrost covered with the boreal forest can influence vegetation composition, surface soil moisture, and the active layer. Since wildfires on permafrost occur extensively in unpredictable areas, remote sensing is a useful tool for monitoring burn severity and ecosystem changes. Optical spectral indices such as the differenced normalized burn ratio (dNBR) and normalized difference vegetation index (NDVI) were traditionally used to detect burn severity and vegetation regrowth. However, since optical imagery is significantly affected by cloud cover and weather conditions, there is a limitation in acquiring temporally dense images. Synthetic Aperture Radar (SAR) can obtain images regardless of day/night or weather conditions, so it is possible to densely observe the area of interest spatiotemporally. In addition, SAR images, unlike optical images, can acquire information on the active layer of the permafrost in the winter season. This study aimed to analyze winter season time-series SAR backscattering coefficient change with burn severity in south Northwest Territories, Canada using optical and SAR data. The study area, south Northwest Territories, belongs to the discontinuous permafrost zone and consisted of the taiga. Burn severity and vegetation regrowth were estimated by dNBR and NDVI using optical imagery. To increase the temporal resolution, Landsat-8 OLI and Sentinel-2 MSI were acquired through the cloud-based Google Earth Engine (GEE) in the summer season. C-band dual-polarization Sentinel-1 and X-band single-polarization TerraSAR-X were obtained to understand the multi-frequency backscattering coefficient to fire-induced changes. The changes pattern of the SAR backscattering coefficient varies according to the burn severity, especially in the winter season, not affected by vegetation and soil moisture. It can be seen that the wildfires affected the changes in the scattering mechanism in permafrost on the boreal forests. These results represent that C-band and X-band SAR images have the potential to monitor the changes of the active layer with burn severity.
Miocene Bontău volcanic complex (Apuseni Mts., Romania); volume calculations and edifice reconstruction
Authors: Mirea Viorel Marian , Seghedi Ioan
Published: March 2022

The evolution of the largest composite volcano in the Zărand basin of the Apuseni Mts., named recently Bontău has been associated with close-by dome complexes. It was built by calc-alkaline lavas and pyroclastic deposits (basaltic andesites to andesites). According to the available K/Ar data the Bontău Volcano is known to be active roughly between ~14-10 Ma and presently is covering an area of ~ 807.22 square km.

The initial edifice of the volcano is presently not anymore conserved and now the Bontău volcano it is composed of central edifice remnants named NDD, CVE and CVW surrounded by debris avalanche (DADs) and associated debris flow deposits. The stratovolcano had two stages; first effusive-explosive generated in the same time with the Gurahonţ, Aciuţa and Vârfuri close-by Domes up to ~12 Ma. The second stage, after ~12 Ma started with effusive dome at the top of the Bontău volcano. Further Plinian eruption and then gravitational collapses have emplaced massive volume DADs, widely distributed all around the volcano. Four DADs units are defined, corresponding to collapsed structures directed initially to the west and east and then to the south and north. This is the first calculations volumes of the Bontău volcanic complex, including edifice remnants, associated Domes and the DADs with the intention to reconstruct the initial edifice of Bontău volcano. DADs cover an extensive area around the former volcano edifice; around 346.14 square km and the central edifice remnants cover around 40.65 square km. Two DADs units surrounding the remnants of the former volcanic edifice are E-W directed (EDA, WDA) and the other two are N-S directed (NDA, SDA). The largest unit it is the EDA and characterized by highest run out of debris avalanches (~19 km) filling the Zărand basin interior. The calculations took into account the Pliocene-Quaternary erosion processes including the Crişul Alb River and its tributaries. According to volume calculations we reconstructed the volcano edifice that most probably had a base diameter of ~ 12 km and a height of ~2096 m. The edifice is looks similar in size with other composite volcanoes (i.e., present day Ruapehu volcano, North Island, New Zealand).

 
ModE-Sim - A new medium-size AGCM ensemble to analyze climate variability in the modern era
Authors: Hand Ralf , Samakinwa Eric , Hövel Laura , Valler Veronika , Brönnimann Stefan
Published: March 2022

We introduce a 36 to 40-member ensemble of simulations with the atmospheric general circulation model ECHAM6 that is designed to form the basis for a 3-dimensional climate reconstruction dataset in the PALAEO-RA project. It covers the years 1420 to 2009, the period for which combining natural proxies such as tree rings and archives of society such as documentary data allows to perform global climate reconstructions. However, the information provided by these historical sources is usually sparse in temporal and spatial resolution. Our simulations provide the necessary background for data assimilation and thus complement the historical information by adding physical constraints implemented in the model formulation. Our experimental setup is designed to determine the range of internal climate variability under prescribed forcings. It is oriented on the PMIP4 setup with slight modifications, using realistic ocean boundary conditions (SST and sea ice cover) and radiative forcings while also accounting for uncertainties in these.

Our presentation will give an overview of our experimental setup and show the results of the first applications. We present an evaluation of the ensemble, including measures on how well the ensemble can sample the internal variability of some variables of interest. Beyond this, we hope to stimulate a discussion on possible further applications.
Using 3D full-waveform inversion to investigate bottom-simulating reflectors
Authors: Frahm Laura , Davy Richard , Bell Rebecca , Morgan Joanna , Arai Ryuta , Bangs Nathan , Henrys Stuart , Barker Daniel
Published: March 2022

We present velocity images across a bottom-simulating reflector (BSR) recovered using 3D high-resolution full-waveform inversion (FWI) and discuss its use as a tool for understanding the nature of the BSR.

FWI is a seismic imaging technique which generates highly resolved physical property models of the subsurface. FWI uses the full recorded waveform for inversion which leads to a superior resolution compared to other imaging methods, but also makes it computationally more expensive. Relative to 2D inversions, 3D FWI leads to image improvements due to an increase in azimuthal coverage and ability to map out-of-plane arrivals to the correct location, which is particularly important in a complex geological setting. Therefore, next to the advantage of a fully resolved 3D structure, the model will also be more accurate.

Caused by gas hydrate in an upper layer and/or free gas in a lower layer, a BSR indicates the base of the gas hydrate stability zone. This significant change of the physical properties in the upper few hundred meters of the marine sediment produces a distinct reflection, i.e. the BSR, that can be seen in the seismic image.

We are imaging and investigating a BSR at Puke Ridge, a thrust ridge on the accretionary wedge of the northern Hikurangi subduction margin, offshore the North Island of New Zealand. We are using seismic multichannel streamer data, belonging to the NZ3D dataset collected in 2018, to invert for the P-wave velocity. The resolved velocity model displays the geometry and the structure of a BSR characterised by a velocity increase followed by a sudden decrease and provides us with accurate velocities which we can use for rock physics modelling and interpretation.
Influence of subsurface tropical instability waves on sea surface temperature in the tropical Atlantic 
Authors: Specht Mia Sophie , Jungclaus Johann , Bader Jürgen
Published: March 2022

Tropical Instability Waves (TIWs) at the equatorial Atlantic Ocean lead to SST cooling due to enhanced mixing and heat fluxes above the EUC core. This phenomenon has been studied predominantly at the equator and to the north, where TIWs are most pronounced. However, a recent study has shown the presence of subsurface TIWs in the Atlantic Ocean, which frequently occur to the south of the equator. As TIW induced subsurface mixing leads to SST cooling at the equator, we suspect a similar cooling may occur in the Southern Hemisphere due to the presence of subsurface TIWs. Using one decade of high-resolution ICON ocean simulations, we investigate such effect of subsurface TIWs in the southern hemisphere on SST in the tropical Atlantic Ocean. The analysis of all terms of the mixed layer heat budget allows for the investigation and quantification of the processes involved in subsurface TIW induced SST changes.
MAPPING OF Fe2O3 , Nb and TiO2 , AS A SUPPORT TO CLASSIFY OUTCROPPING MATERIALS IN” MORRO DOS SEIS LAGOS” CARBONATITE COMPLEX, BRAZILIAN AMAZON
Authors: Rodrigues Niriele , Silva Júlio Cesar Lopes da , Silva Renan Pereira Marinatti da , Pinheiro Helena Saraiva Koenow , Carvalho Junior Waldir
Published: March 2022

The study goal was the preliminary mapping of Fe2O3, Nb and TiO2 contents to support of the classification of outcropping materials (focused on laterite types), in “Morro dos Seis Lagos”, in Brazilian Amazon. The methodological procedures were based on machine learning tools, gathering Sentinel-2 MSI and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor data, numerical terrain models (all with 20 m spatial resolution), and geochemical legacy dataset from the Geological Survey of Brazil (CPRM). The input geochemical dataset was subdivided in training dataset (341 samples) and validation dataset (85 samples) to apply the Random Forest (RF), in 60 loops of iteration, and the model’s performance were evaluated through the average values of the metrics (R2, RMSE and MAE). Subsequently, the resulting average maps were combined using cluster analysis (k-means) via unsupervised classification, performed at the R environment through the Vegan package, where the number of resulting classes was optimized taking into account the “Simple Structure Index” (SSI) criterion. Different cluster grouping was tested considering classes number (6 to 10) and interactions (0 to 8000), and the resulting classes (zones) were contrasted with available geological map.  The results showed the best performance in modeling via the Random Forest (RF) model associated with Recursive Feat Elimination (RFE) for the elements Nb (R2=0.08, RMSE = 0.86, MAE = 0.66), TiO2 (R2=0.14, RMSE = 3.90, MAE= 2.56) and Fe2O3 (R2=0.23, RMSE =19.77, MAE = 14.12). Based on the results obtained via preliminary cluster analysis, the best optimization was achieved grouping in 9 classes, according to SSI criterion. The results showed agreement when compared to the classes of the geological map available for the area, but with better detailing of the laterite facies. The conclusions of the preliminary study pointed out that advances regarding the scale detail provided better understanding the behavior of the variability in laterite and talus deposits with the support of machine-learning tools and covariates from remote sensing data. However, improvement in the cluster classification can be achieve by adding other geochemical compounds and testing different predictive models.
Flood susceptibility mapping using an Artificial Neural Network model: the case study of Southern Italy
Authors: Del Vecchio Michele , Balestra Filippo , Pedone Maria Antonia , Pirone Dina , Spina Danilo , Manfreda Salvatore , Menduni Giovanni
Published: March 2022

In Italy, flood hazard maps are traditionally obtained through hydrologic-hydraulic modelling. In fact, numerical simulations are usually limited to the main river or specific tributaries leaving a significant part of the territory unclassified. Therefore, there is a growing interest toward alternative techniques that allow to ensure a complete description of flood risk. Since flood hazard mapping is crucial for risk reduction, sustainable development and an appropriate land use planning, this study suggests a rapid methodology to delineate flood prone areas at large scale based on machine learning techniques in a GIS environment. Due to the large availability of recorded flooded areas, the procedure aims to select, combine and interpret observed flooding with predisposing factors which may be used to predict flood susceptibility of a specific site. The study applied and assessed an Artificial Neural Network (ANN) in Southern Italy to produce a flood susceptibility map based on homogeneous physiographic units. This model originally included a large set of influencing factors, classified and selected with an analytical hierarchy process method. The information on recorded flooded areas and the delineation of marginal hazard areas ensured a consistent training of the artificial neural network with early stopping method. The area under curve (AUC) of receiver operating characteristic (ROC) curves were used to evaluate the predictive accuracy of the proposed models. The results are encouraging and seem to support the use of susceptibility as simple and useful tool for the management of hydraulic risk and the flood emergencies. Moreover, the proposed approach may help and support rapid review of flood risk mapping in view of the ongoing environmental and climatic changes, which may support adaptation policies in the next future. Notwithstanding flood hazard maps remain the official normative reference, flood susceptibility analysis could represent a synergic approach for a quick flood prone areas analysis.   
Evolution of the thermally stratified layer in the outer core of Mercury
Authors: Zhao Yue , Deproost Marie-Hélène , Knibbe Jurriën , Rivoldini Attilio , Van Hoolst Tim
Published: March 2022

Mercury’s high core mass ratio means that its core evolution could have strong implications for its mantle dynamics, surface geology, and the generation of a dynamo. Radial contraction, present-day magnetic field, ancient crustal magnetisation, and early extensive volcanism are some of the observations that are controlled by the thermal evolution of Mercury’s interior and therefore influenced by the core.

The low intensity and lack of small-scale variations in Mercury’s present-day magnetic field can be explained by a convective liquid below a thermally stratified core layer where heat is transported conductively. Numerical studies confirmed the plausibility of a sub-adiabatic heat flow at the core-mantle boundary, giving rise to the thermally stratified layer. Investigating the conditions leading to the formation of the thermally stratified layer, and its evolution, is of crucial importance for our understanding of Mercury’s geological and geophysical history.

We couple mantle and core thermal evolution to investigate the conditions under which the thermally stratified layer is formed in the liquid core, and to study the interactions between the core and the mantle. Events such as the cessation of convection in the mantle may strongly influence the core-mantle boundary heat flow and affect the thickness of the thermally stratified layer in the core. Our results highlight the importance of coupling mantle evolution with that of the core, taking into account processes such as melting in the mantle and solidification of an inner core, and the effects of a sub-adiabatic core-mantle boundary heat flow.
Statistical characterization of the physical mechanisms under Sea Breeze conditions in a complex terrain island
Authors: Grau Ferrer Antoni , Jiménez Maria A.
Published: March 2022

The island of Mallorca (western Mediterranean Sea) is taken in this work to statistically characterize some of the physical mechanisms involved during Sea Breeze (SB) conditions. It is a complex terrain island with two main mountain ranges (at the north and east) and an elevated area in its center, which defines three main basins: Palma in the west, Alcudia in the northeast and Campos in the southwest.

The physical mechanisms that take place under SB conditions are analysed through the inspection of data from automatic weather stations (AWS) from the Spanish Meteorological Agency (AEMET) during the period 2009–2021. Hourly satellite-derived land-surface and sea-surface temperatures (LST and SST, respectively) are used to compute the surface temperature difference (LST–SST) in the three basins. Besides, a method (Grau et al, 2020) is taken to select the SB events separately in the three basins using data from AWS during the warm months of the year (from April to September).

Results show that the surface temperature difference changes in the three basins pointing that other physical mechanisms are present during SB conditions. For instance, it is explored the role of the large-scale winds in the strength of the SB, the influence of the shape of the basin in the propagation of the SB front and the importance of the vertical temperature gradient (T850hPa – LST) for the SB initiation. It is found that there are differences in the SB features of the three basins (maximum wind speed, initiation and duration of the SB, strength of the horizontal thermal gradient) and SB conditions are not simultaneously met. Besides, interactions between SB and locally-generated winds at the slopes that close the basins are important and they can enhance/diminish the wind locally.
Atmospheric response to solar flares, coronal mass ejections and magnetospheric energetic particle precipitation during September 2017
Authors: Mironova Irina , Pikulina Polina , Karagodin Arseniy , Rozanov Eugene , Sukhodolov Timofei , Yakovchuk Olesya
Published: March 2022

The atmosphere response to exceptional solar activity in early September 2017 at a minimum of solar cycle 24 is analysed. The beginning of the intensive solar-terrestrial disturbances was the Sun active region AR2673, which produced several powerful solar flares class X with the strongest flare X9.3 of solar cycle 24 on September 6, 2017, and X1.3 on September 7, 2017. This flare produced increasing irradiance in the extreme ultraviolet and soft X-ray ranges of the solar spectrum that are important the most for the sunlit regions of the upper mesosphere and the lower thermosphere. After these flares and coronal mass ejections began G4 - severe geomagnetic storm on September 7-8, 2017 with Ap = 106. Moreover, the second strongest flare X8.2 of Solar Cycle 24 on September 10, 2017, generated instantly the Ground Level. Energetic particle precipitation during disturbances of September 2017 led to increasing ionization rates as well as increased chemical components of the middle polar atmosphere leading to ozone destruction. Using HAMMONIA model we compare the atmospheric separate responses to the solar flares, proton and electron precipitations.

This work presents new results that add to our growing understanding of how impulsive solar and magnetospheric energetic particle precipitation as well as solar flares affect the Earth’s atmosphere system and provides a foundation for understanding their cumulative impacts on the atmosphere and climate.

 

The work was done and supported by a grant from the Russian Science Foundation (RSF project No. 20-67-46016). The co-authors work in the St. Petersburg State University "Laboratory for the Study of the Ozone Layer and Upper Atmosphere" with the support of the Ministry of Science and Higher Education of the Russian Federation under contract 075-15-2021-583.
Analysis of Historical Climate Scenarios of Turkey related to temperature and precipitation for comparing CMIP5 and CMIP6 protocols.
Authors: Hazar Ipeknur , Aksu Aleyna Nur , Yogun Buket , Dursun Bahattin Can , Tan Elcin
Published: March 2022

In the last decade, records have been broken in Turkey's temperature and precipitation observations. In 2020, including the effect of increasing urbanization, the measured temperatures in Istanbul were about 3 °C higher than the 100-year monthly average. In addition, the frequency and intensity of excessive precipitation, especially in northern Turkey, show an increasing trend. Moreover, the change in precipitation patterns is also observed due to climate change. Therefore, to decide Turkey's strategies to combat climate change, it is necessary to determine how accurately the climate model results reflect these changes. For this reason, this study aims to determine the biases of the historical climate models compared with observations. Moreover, comparisons of these models with mild and dramatic scenarios in the CMIP5 and CMIP6 protocols are discussed. The climate models (INM-CM4 and INM-CM5; CNRM-CM5.2 and CNRM-CM6-1; and MRI-ESM1 and MRI-ESM2-0) that were not analyzed before were studied to construct an ensemble overall. Thus, it is aimed to create climate model ensembles for temperature and precipitation. Accuracies of the selected climate models are analyzed by comparing the results of the models with the observations in the 1965-2015 periods utilizing ten-year probability distribution fractions. In addition, simple Daily precipitation intensity index (ECASDII), precipitation days index (ECAPD), extremely wet days index (ECAR99P) analyzes for precipitation and very warm days index (ECATX90P), warm nights index (ECATN90P), and intra-temperature analysis for precipitation. -period extreme temperature range (ECAETR) indices were analyzed. Preliminary results show that climate models simulate temperature changes more accurately than precipitation changes for Turkey. In addition, CMIP6 results were more advantageous than CMIP5 results.