bluuebunny/crossref_metadata_2025 huggingface dataset:
Palaeosecular variation in the Miocene and the first non-zonal time-averaged field model of that era.
Authors: Engbers Yael , Bono Richard , Holme Richard , Biggin Andy
Published: March 2022

Reconstructions of the geomagnetic field behaviour over long periods of time throughout history are important for understanding of geomagnetic field evolution and documenting the longevity of certain features. Statistical studies of palaeosecular variation inform us regarding the structure and behaviour of the geomagnetic field. Here we present a new data compilation, PSVM, of high-quality directional data from the Miocene era (5.3 – 23 Ma). Our compilation comprises 1454 sites from 44 different localities, each with at least 10 sites. We use this database to calculate new Model G parameters for PSVM with varying selection criteria. Our preferred database, , has the selection criteria of n ≥ 5, k ≥ 50, a Vandamme cutoff applied and at least 2 reversals shown within the 10 or more sites of a locality. This produced a Model G fit with a parameter of 15.7° (13.0° - 18.7°). This value is substantially higher than any of the Model G a parameters published for the past 10 Myrs or any other studied era, implying a less stable geomagnetic field in the Miocene. PSVM also enables the creation of the first non-zonal time-averaged field (TAF) models of the Miocene, called MTAM1. After separating our data into normal (PSVMN) and reversed (PSVMR) datasets, separate models for the two states were created. No substantial differences were found between the models (MTAM1N and MTAM1R, respectively), suggesting symmetry in the morphology of the magnetic field in the Miocene. There is no evidence for a previously hypothesised "memory" of the field after a reversal for this era. Instead, non-dipole structure appears to reverse simultaneously with the dipolar structures. After observing this symmetry, we compute a TAF model for the complete Miocene dataset (PSVM), enhancing the data distribution and thus the robustness of the model. In all versions of the models, a reverse flux patch (RFP) is seen under the South Atlantic. Our findings suggest a more variable magnetic field in the Miocene era compared to the past 10 Myrs, implying that the geodynamo was driven by a more strongly convecting liquid core producing a less dipole dominated field on average. In addition, we found a recurring RFP under the South Atlantic that was sufficiently frequent and stationary to appear in a TAF model, giving evidence for a recurring or consistent anomalous feature in the South Atlantic region in the Miocene, with longevity on a multi-million-year timescale.
Impact of Holuhraun volcano aerosols on clouds in cloud-system resolving simulations
Authors: Haghighatnasab Mahnoosh , Kretzschmar Jan , Block Karoline , Quaas Johannes
Published: March 2022

Increased anthropogenic aerosols result in an enhancement in cloud droplet number concentration Nd, which consequently modifies cloud and precipitation process. It is unclear how exactly cloud liquid water path (LWP) and cloud fraction respond to aerosol perturbations. A volcanic eruption may help to better understand and quantify the cloud response to external perturbations, with a focus on the short-term cloud adjustments. The goal of the present study is to understand and quantify the response of clouds to a selected volcanic eruption and to thereby advance the fundamental understanding of the cloud response to external forcing. In this study we used the ICON (ICOsahedral Non-hydrostatic) model at numerical weather prediction setup  at a cloud-system-resolving resolution of 2.5 km horizontally, to simulate the region around the Holuhraun volcano for the duration of one week (1 – 7 September 2014). A pair of simulations, with and without the volcanic aerosol plume, allowed us to assess the simulated effective radiative forcing and its mechanisms, as well as its impact on adjustments of LWP and cloud fraction to the perturbations of Nd. In comparison to MODIS (Moderate Resolution Imaging Spectroradiometer) satellite retrievals, a clear enhancement of Nd due to the volcanic aerosol is detected and attributed. In contrast, no changes in either LWP or cloud fraction could be attributed. The on average almost unchanged LWP is a result of some LWP enhancement for thick, and decrease for thin clouds.
Seismic and multi-parameter 1D reference models of the upper mantle
Authors: Civiero Chiara , Lebedev Sergei , Xu Yihe , Bonadio Raffaele , Fullea Javier
Published: March 2022

1D reference Earth models are widely used by the geoscience community and include global, regional and tectonic-type reference models. Seismic 1D profiles are used routinely as reference in imaging studies. Multi-parameter models can also include density, composition, attenuation, lithospheric thickness and other parameters, of interest in a broad range of studies. The recent growth in the number of seismic stations worldwide has yielded a dramatic increase in the global sampling of the Earth with seismic data and presents an opportunity for an improvement in the global and tectonic-type reference models. Concurrent developments in computational petrology have provided methods to constrain self-consistent multi-parameter Earth models with seismic and other data. Here, we use a large global dataset of Love and Rayleigh fundamental mode, phase-velocity measurements, performed with multimode waveform inversion using all available broadband data since the 1990s, and compute phase-velocity maps at densely spaced periods in a broad, 17-310 s period range. We then invert the phase velocity curves averaged globally and across 8 tectonic environments (4 continental: Archean cratons, stable platforms, recently active continents, and active rift zones; and 4 oceanic: old, intermediate and young oceans, and backarc regions) for 1D reference models of the upper mantle. For each tectonic type, a multi-parameter 1D model is computed in a petrological inversion, where the lithospheric thickness and temperature at the bottom of the lithosphere and in the underlying mantle are the inversion parameters, and steady-state conductive lithospheric geotherms are assumed. Lithospheric and asthenospheric compositions are taken from geochemical databases, and seismic velocities, densities and Q are computed from composition, temperature and pressure using computational petrology and thermodynamic databases. The models quantify the age dependence of the lithospheric thickness and temperature in continents and oceans. Radial anisotropy is also determined and shows notable variations with depth and with tectonic environments. For most tectonic types, the smooth, accurate observed phase velocity curves can be fit by the 1D models with a misfit under 0.1-0.2% of the phase velocity value. Additionally, we compute models with minimal complexity of seismic velocity structure, also fitting the data but without a sub-lithospheric low-velocity zone as in the thermal multi-parameter models. These purely seismic models, similar in appearance to ak135, do not correspond to realistic geotherms but provide useful reference for seismic imaging studies in different environments.
The role of the Belize River in localised coastal ocean acidification. 
Authors: Cryer Sarah , Felgate Stacey , Brown Peter , Carvalho Filipa , Strong James , Wood Terry , Andrews Gilbert , Rosado Samir , Young Arlene , Goddard-Dwyer Millie , Loucaides Socratis , Sanders Richard , Evans Claire
Published: March 2022

The Mesoamerican Barrier Reef, the second largest barrier reef in the world, is vitally important to the ecology and economy of Belize and neighbouring countries. Coral reefs are inherently vulnerable to ocean acidification and those exposed to significant riverine input may be under enhanced threat. In tropical rivers pCO2 levels may be linked to land use in their catchment, with conversion of pristine forest to agricultural land potentially enhancing carbon flux to the coastal ocean. We investigated the effect the Belize River may have on the carbonate chemistry of surrounding coastal ocean, applying a multidisciplinary methodology. Water samples were collected and measured for: total alkalinity; dissolved inorganic carbon (DIC); and δ13CDIC; and were complemented by pH and pCO2 data acquired from sensors mounted on an autonomous surface vehicle. Samples were collected from the source of the Belize river to the mouth and out past the barrier reef.  pCO2 measuring >1000-µatm at the mouth of the Belize River suggests local high levels of respiration and low pH water being discharged into the coastal ocean. δ13CDIC samples were taken to identify terrestrial DIC signatures and used in combination with sensor data to identify potential controls on coastal pH. There was a distinct difference in δ13CDIC along the river with a range of 27 ‰ to - 13‰, while coastal δ13CDIC was heavier with a range of  -11.5‰ to 1.5 ‰. These results demonstrate the complexity of processes that control coastal ocean acidification, which has implications for coastal economies that are heavily dependent on healthy coral reefs as a resource.
Buried geomorphic features in the North-western Irish Sea: markers of the last glaciation and deglaciation episodes
Authors: Michel Guillaume , Coughlan Mark , Emery Andy , Arosio Riccardo , Wheeler Andrew
Published: March 2022

To understand the advance and retreat of the British and Irish Ice Sheet (BIIS), geomorphic features have been extensively characterised onshore. The extent of these features in the Irish Sea has been poorly constrained, even though the Irish Sea Ice Stream (ISIS) was the largest drainage system of the BIIS and had a strong impact in shaping the present-day seafloor. Previous studies have highlighted the occurrence of till surfaces, glacio-marine and transitional stratigraphic units to marine environments. Constraining the extension of these units and characterising the associated geomorphic features is important to any attempt to reconstruct the history of the BIIS evolution since the Last Glacial Maximum.

This study presents new information produced by interrogating large geophysical datasets of sub-bottom profiler, single-channel Sparker, and multibeam echosounder bathymetry in the North-Western Irish Sea, from Dundalk Bay to Lambay Deep. These data spatially map the complex sub-surface stratigraphy, comprising different glacial and post-glacial units and the geomorphic features they form, including grounding-zone wedges, channels, and iceberg scouring. Initial interpretation of these features has been performed with regard to established stratigraphic frameworks and regional glacial and postglacial geodynamic models. This presentation will focus on the results of the geomorphic feature interpretation, with the aim of constraining the ISIS advance and retreat in the North-western Irish Sea, filling a critical gap in our understanding of the demise of the BIIS.
Behind every robust result is a robust method: Perspectives from a hydrological case study
Authors: Fenicia Fabrizio , Kavetski Dmitri
Published: March 2022

Stringent modelling methods and diagnostic techniques for improving the credibility of model predictions have received a lot of attention in the hydrological literature. However, previous discussions have revolved mainly around theoretical aspects, and arguably lacked persuasive examples. In this work, in order to illustrate the weaknesses of widespread modelling practices, we instead provide an applied perspective. In particular, we present the case of a distributed rainfall-runoff model that evolves in response to progressively more stringent application of model diagnostics. Through this example we demonstrate the usefulness of the following methodological instruments: (i) benchmarking model results against a null-hypothesis model, (ii) testing model predictions in space-time validation, and (iii) carrying out controlled model comparisons. These instruments, arguably still underutilized in the hydrological community, offer important diagnostic capabilities to increase the rigor of hydrological and environmental model applications.  Therefore their more widespread application is encouraged.
Separation of gravimetric and magnetic anomalies with different degrees of regionality in the Eastern Carpathians, Romania
Authors: Asimopolos Natalia-Silvia , Asimopolos Laurentiu
Published: March 2022

The gravity and magnetic anomalies separation operation consists in determining the number of sources, the characteristics of each (depth, density, shape, and dimensions) so as to result in cumulative total anomaly, measured at the Earth’s surface. This separation has to be done in the context of the fundamental ambiguity of gravimetric and magnetic information, based on the cause-effect ratio. There are various methods for achieving this separation of anomalies. This paper presents some examples of the use of the moving average method and the polynomial trend surfaces. In particular, we presented the results of the mobile mediation with different windows compared to the tendency surfaces with different degrees, for a case study in Eastern Carpathians mountains area. For this study we used data available from several sources.

From the International Gravimetric Bureau we used gravimetric data for the WGM2012 geoglobal model: Bouguer anomaly for density 2.67 g / cm3, outdoor anomaly, isostatic anomaly, gravitational disturbance and altitude.

From the geophysics portal of the Geological Institute of Romania we used the magnetic data resulting both from the scanning of the national geomagnetic maps and from the catalogs of measurements from the archive. We also used the deep geological sections made on the basis of seismic data, corroborated with gravimetric and magnetic data that cross the Eastern Carpathians.

Other data used for depth correlations were the isobath map of the Moho surface, the Conrad surface, the geoid, and the quasigeoid.

For the study of deep tectonics based on all the data used we used the correlation coefficient between various parameters, calculated in movable windows of different sizes both in plan and in space. For this we have developed specific calculation programs.  The moving average is a direct method for separating regional effects and local (residual) effects. Polynomial trend surfaces analysis contributes to the recognition, isolation and measurement of trends that can be calculated and represented by analytical equations, thus achieving a separation in regional and local variations. The analytical expressions of the polynomial trends based on the least squares method were calculated, highlighting the regional trend caused by the deep structures. Then, by calculating the residual values resulting from the difference between the initial values and the trend values from the network nodes used, we highlighted the superficial local effects. We also obtained information about the regional trend caused by geological structures at medium and large depths, by calculating the difference between gravity parameters, obtained with different moving average windows or tendency surfaces with different degrees, interpolated in same network.
Global NH3 emissions from livestock management : development of a module within a land surface model and impact on atmospheric chemistry
Authors: Beaudor Maureen , Vuichard Nicolas , Lathière Juliette , Van Damme Martin , Clarisse Lieven , Hauglustaine Didier
Published: March 2022

Ammonia (NH3) is a key species in the atmosphere, playing a crucial role in air quality and climate through the formation of sulfate and nitrate particles. Moreover, NH3 surface deposition alters ecosystems. About 85% of NH3 global anthropogenic emissions are related to food and feed production and in particular to the use of mineral fertilizers and manure management. Even though the estimate of the emissions from livestock can reach 36 Tg N/yr, they are generally not represented explicitly in global land surface models.  Most global chemistry transport models rely on bottom-up emission inventories subject to large uncertainties. Our objective consists of replacing these external emissions data by dynamical emissions computed by ORCHIDEE, a terrestrial ecosystem model including the carbon and the nitrogen cycles. This new version of the ORCHIDEE model includes a detailed integrated scheme for livestock management, from housing and storage to grazing emissions. Ultimately, our work aims at developing an interactive nitrogen cycle model in a coupled climate-chemistry-vegetation model in order to investigate the impact of NH3 emissions from livestock on atmospheric chemistry and climate, and the associated feedbacks.

In this study, we describe and present global NH3 emissions from livestock calculated based on the new version of the ORCHIDEE land surface model . We evaluate NH3 emissions simulated by ORCHIDEE with previous inventories and model estimates. An analysis of key parameters driving the soil NH3 emissions (pH of the manure, the timing of the N application, the surface atmospheric concentration etc… ) have also been performed in order to assess the sensitivity of the simulated emissions. Last, we investigate the impact of prescribing these new simulated emissions on atmospheric chemistry, using the global atmospheric chemistry transport model LMDZ-OR-INCA. The simulated NH3 atmospheric columns are evaluated by global and regional comparisons with the spaceborne IASI instrument measurements. The products used are monthly gridded NH3 distributions using morning observations of IASI-(Metop)A and IASI-(Metop)B for the period 2011-2017. In addition, we compare the ammonia atmospheric columns simulated based on the dynamical livestock emissions and based on reference bottom-up emission inventories. Finally, we investigate the impact of the different NH3 emission inventories on key atmospheric species concentrations.
Modelling ridge jumps in back-arc basins at different scales
Authors: Magni Valentina , Schliffke Nicholas , van Hunen Jeroen , Gueydan Frédéric , Allen Mark , Naliboff John , Prada Manel , Gaina Carmen
Published: March 2022

The structure of oceanic back-arc basins reflects the dynamics of the subduction zone they are associated with. Often, the basement of these basins is not only composed of oceanic crust, but also of exhumed mantle, fragments of continental crust, intrusive magmatic bodies, and a complex mid-ocean ridge system characterised by distinct relocations of the spreading centre. These features are a direct consequence of the transient nature of subduction zones. Here, we show results from different types of numerical models that aim at understanding how back-arc basins are shaped by subduction dynamics.

We present 3D numerical models of back-arc spreading centre jumps evolving naturally in a homogeneous subduction system surrounded by continents without a trigger event (Schliffke et al., 2022). We find that jumps to a new spreading centre occur when the resistance on the boundary transform faults enabling relative motion of back-arc and neighbouring plates is larger than the resistance to break the overriding plate closer to trench. Time and distance of spreading centres jumps are, thus, controlled by the ratio between the transform fault and overriding plate strengths. We also present results from 2D numerical models of lithospheric extension with asymmetric and time-dependent boundary conditions that simulate multiple phases of extension due to episodic trench retreat (Magni et al., 2021). We show that multiphase extension can result in asymmetric margins, mantle exhumation and continental fragment formations. We find that the duration of the first extensional phase controls the final architecture of the basin. Finally, we show that our models can explain many features observed in present-day and extinct back-arc basins.

Magni, V., Naliboff, J., Prada, M., & Gaina, C. (2021). Ridge Jumps and Mantle Exhumation in Back-Arc Basins. Geosciences, 11(11), 475.

Schliffke, N., van Hunen, J., Gueydan, F., Magni, V., & Allen, M (2022). Episodic back-arc spreading centre jumps controlled by transform fault to overriding plate strength ratio. Accepted for publication in Nature Communications.

 

 
The influence of different groundwater levels (GWL) on C and GHG dynamics of an agricultural used wetland area
Authors: Antonijevic Danica , Dietrich Ottfried , Monzon Oscar , Niedermayr Barbara , Vaidya Shrijana , Macagga Reena , Augustin Juergen , Hoffmann Mathias
Published: March 2022

Agricultural used wetlands with high SOC stocks cover large parts of northeast (NE) Germany. Drainage and modification of groundwater levels by agricultural water management during the last century not only lead to a change in their hydrological processes but also reversed many biogeochemical processes like soil C dynamics and GHG emissions. In addition, climate projections indicate that climate change will substantially alter seasonal precipitation and temperature regimes in NE Germany with an increasing risk of severe summer droughts such as in 2018. Both might have the potential to significantly increase SOC stock losses and GHG emissions. Hence, there is an emergent importance to investigate the interconnectivity between water level, soil C dynamics, and GHG emissions.

To better understand this interconnectivity, we investigated the influence of a different GWL on dynamics of GHG emissions and the net ecosystem C balance (NECB) as a proxy for SOC stock changes. Therefore, GHG emission measurements and estimates of NECB were performed for four weighable lysimeters containing soil monoliths, which were established during 2009 in an agricultural used wetland area (Spreewald region, 51◦52’N, 14◦02’E). The study site represents an agricultural used (pasture) grassland typical for the Spreewald region. Weighable lysimeters were used to simulate two different GWL regimes: growing season dropdown of GWL due to e.g. summer drought vs. no growing season GWL dropdown. GHG emission measurements (CO2 (Reco and NEE), CH4 and N2O) were conducted campaign wise every 2 to 4 weeks from 2021 onwards, using a manual (N)FT-NSS closed chamber system (Livingston and Hutchinson 1995). In addition, environmental conditions, aboveground biomass development (e.g. plant height, RVI, NDVI) and in situ water parameters (e.g., oxygen, pH, hydrogen carbonate, el. conductivity, temperature, redox potential) were obtained.

Here we present GHG emission measurements and NECB estimates for the first study year of 2021. Higher GWL generally resulted in a lower biomass production. Consequently, clear differences between the two different GWL´s were also obtained in case of derived CO2 flux components Reco and GPP as well as to a lower extend for overall NEE, with higher GWL showing an only slightly higher overall net CO2 exchange. Thus, higher NECB values were detected for lower GWL. In contrast, overall GHG emissions (incl. CO2, CH4 and N2O) were lower for lower compared to higher GWL.
Active gyrotactic stability of microswimmers using hydromechanical signals
Authors: Gustavsson Kristian , Qiu Jingran , Mousavi Navid , Zhao Lihao
Published: March 2022

Many plankton species undergo daily vertical migration to large depths in the turbulent ocean. To do this efficiently, the plankton can use a gyrotactic mechanism, aligning them with gravity to swim downwards, or against gravity to swim upwards. Many species show passive mechanisms for gyrotactic stability. For example, bottom-heavy plankton tend to align upwards. This is efficient for upward migration in quiescent flows, but it is often sensitive to turbulence which upsets the alignment. In this presentation we suggest a simple, robust active mechanism for gyrotactic stability, which is only lightly affected by turbulence and allows alignment both along and against gravity.

 
Cross-correlation of optical satellite data for the detection and monitoring of slow-moving landslides in northwestern Argentina
Authors: Mueting Ariane , Bookhagen Bodo
Published: March 2022

The increase in freely available optical satellite data with 10-15 m spatial resolution offers new opportunities to monitor slow-moving landslides and study their past movements through image cross-correlation in difficult-to-access regions around the world. Here, we explore this potential using Landsat-8 and Sentinel-2 optical satellite imagery to detect and quantify slope movements in the northwestern Argentine Andes over the past eight years. Our study takes advantage of the large spatial and temporal availability of optical satellite imagery, but we also show the caveats associated with cross-correlation for slow-moving targets. The northwestern Argentine Andes, particularly the mountain ranges that border the Central Andean Plateau (Altiplano-Puna Plateau), are predisposed to slope movements because of their steep hillslopes, weakened lithologies, sparse vegetation cover, and frequent rainfall events. Previous studies based on radar interferometry have identified several landslides moving at ~1 m/yr throughout our study area. We use these areas of known offset to identify optimal processing routines, evaluate their accuracy, and define the limitations of monitoring the movement of slow-moving landslides with optical imagery. We present approaches to pre- and post-correlation filtering to reduce noise and increase signal strength and further validate our results with high spatial resolution imagery (1-3 m). In this way, we aim to better constrain the distribution of slow-moving landslides throughout our study area and understand the driving factors of past and present slope movements at the regional scale.
A high-resolution, high-quantity approach to mollusc shell analysis and linking archaeological with climatic data.
Authors: Hausmann Niklas , Theodoraki Danai , Pinon Victor , Anglos Demetrios
Published: March 2022

This talk will outline how the immediate impact of climatic events on societies of the past can be identified and quantified more robustly by archaeological research using mollusc shell records.

Advances in data acquisition regarding speed and resolution promise improved access to this high-resolution climate archive, and thus an improved interdisciplinary palaeo-perspective. Different to most long-term climate archives, mollusc shells are often found on site and record temperature changes on a seasonal scale, allowing us to measure weather extremes on a resolution that a) would have been immediately noticeable by individuals and b) is essential to subsistence strategies. In particular, we hope to provide a better environmental backdrop to the question of the climatic impact on the Neolithic Dispersal along the Mediterranean coasts and verify extreme short-term events on site, should they have occurred.

We are employing an innovative way of acquiring sea surface temperature (SST) data using a combined approach of stable oxygen isotopes (δ18O) and LIBS-screening (Laser Induced Breakdown Spectroscopy), resulting in a lower quantity of δ18O values required per shell and, as a result, a higher quantity of sampled shells. Our improved data acquisition process enables us to use a high resolution (i.e. +1000 data points per shell record) as well as a high sample quantity (100s of shells) approach, that provides extensive coverage across entire site stratigraphies.

By sourcing our climate data from shell remains found in archaeological layers, we are able to directly compare archaeological information of that layer with the individual climate records, side-stepping the need of radiocarbon-dating either dataset extensively and instead using the shared stratigraphic position to infer temporal concurrence.

This high quantity and high resolution approach produces a combined natural and societal archive, that because of its size can more easily and robustly reveal links between society and the immediate climate change, extreme events and natural hazards it experienced.
Lu-Hf dating of Jurassic eclogites of the Zagros hinterland, Iran: Implications for the timing of Neotethyan subduction initiation
Authors: Jamaliashtiani Rezvaneh , Scherer Erik , K. Schmitt Axel , Hassanzadeh Jamshid
Published: March 2022

The Sanandaj-Sirjan zone (SaSZ) on the northern edge of the Arabia-Eurasia suture in Iran includes a significant high-pressure (HP) metamorphic suite exposed along the upper Zayanderud River north of Shahrekord. Phengitic micas from eclogite in the Zayanderud metamorphic complex (ZMC) yielded 40Ar/39Ar dates ranging from 184 to 173 Ma [1], whereas zircon from an associated anatectic pegmatite gave an average U-Pb age of 176 ± 3 Ma [2]. These data are consistent with a subduction channel metamorphism and rapid exhumation during the Early to Middle Jurassic. To constrain the timing of high-pressure conditions, we have conducted Lu-Hf mineral-whole rock dating on two eclogite samples. The resulting garnet-controlled isochron dates of 171.4 ± 0.4 (MSWD = 1.2) and 175 ± 1 (MSWD = 0.43) Ma have important geodynamic implications as the Jurassic initiation of the Neotethyan subduction in Iran has recently been disputed [3][4]. The metamorphic ages of the ZMC eclogite now leave no doubt that subduction was ongoing along the SaSZ peri-Tethyan margin during the Middle Jurassic.

[1] Davoudian et al., 2016 Gondwana Research 37: 216-240; [2] Jamali Ashtiani et al., 2020 Gondwana Research 82: 354-366; [3] Azizi & Stern, 2019 Terra Nova 31: 415-423; [4] Lechmann et al., 2018 Contrib. Mineral. Petrol. 173 (12): 102
Measuring Background Radiation with a Novel Ionisation Detector Aboard A North Atlantic Voyage
Authors: Tabbett Justin , Aplin Karen , Barbosa Susana
Published: March 2022

Radon and its progeny are well-documented sources of natural radioactivity which can be used as benchmarks for testing a novel ionisation detector. The miniaturised ionisation detector was deployed aboard the NRP Sagres on a SAIL mission in July 2021 which travelled between the Açores and Lisbon in the North Atlantic Ocean. On its voyage, the detector profiled natural background radiation and in-directly detected cosmic ray muons, providing both spectroscopic energy discrimination and count rate data. The detector was simultaneously run with a NaI(Tl) gamma ray counter and other meteorological instruments.

The small form factor and low-power detector, composed of a 1x1x0.8 cm3 CsI(Tl) microscintillator coupled to a PiN photodiode, was able to identify gamma peaks from Bi-214 and K-40, having been calibrated using laboratory gamma sources up to 1.3 MeV. This research aims to investigate the performance of the ionisation detector and behaviour of discrete gamma energies over the duration of the voyage. Additionally, we will show a comparison of the CsI(Tl) based ionisation detector against the gamma ray counter which features a larger NaI(Tl) scintillator.
Precision of Galileo satellite orbits obtained from simulated VLBI observations
Authors: Wolf Helene , Böhm Johannes , Nothnagel Axel , Hugentobler Urs , Schartner Matthias
Published: March 2022

Observing Earth-orbiting satellites additionally to natural extra-galactic radio sources with Very Long Baseline Interferometry (VLBI) radio telescopes offers a variety of new possibilities and allows expanding the research activities of this highly accurate technique. The combination of observations to satellites and quasars permit the determination of the satellite orbit from VLBI observations in the terrestrial as well as in the International Celestial Reference Frame. The latter is enabled by the unique capability of VLBI to determine Universal Time UT1.

In this contribution for the first time, the precision of short satellite orbital arcs determined with simulated VLBI observations to Galileo satellites for different observation geometries using various VLBI networks and arc lengths is investigated. For this purpose, schedules including both, observations to quasars and satellites, are created using the scheduling software VieSched++. The simulations of the scheduled observations and the estimation of the satellite arcs are carried out using the Vienna VLBI and Satellite Software (VieVS). The quality of the estimated orbits is investigated and assessed based on the mean formal errors and the repeatabilities of the individual components of the satellite positions based on Monte Carlo simulations. 
Submarine landslides triggered by the 1663 earthquake (M>7) in the St. Lawrence Estuary, Quebec, Canada
Authors: Mérindol Méril , Saint-Onge Guillaume , Sultan Nabil , Lajeunesse Patrick , Garziglia Sébastien
Published: March 2022

In eastern Canada, the Charlevoix-Kamouraska/Bas-Saint-Laurent (CKBSL) seismic zone presents a seismic hazard almost as high as the active Pacific zone. The major event of February 5, 1663, with a magnitude estimated at > 7 highlights this important seismic hazard. The numerous submarine landslides mapped in the St. Lawrence Estuary in the CKBSL seismic zone suggest that earthquakes have acted as a trigger for submarine slope failures. In this context, the SLIDE-2020 expedition on board the RV Coriolis II in the St. Lawrence Estuary aimed to map, image and sample more than 12 zones of submarine instabilities and their associated deposits. The analysis of sediment cores sampled in the distal sedimentary deposits from these landslides reveals the presence of rapidly deposited layers (turbidites and debrites) directly linked to the submarine landslides. Dating of these landslides with 210Pb and 14C techniques led to the identification of four periods of synchronous emplacement corresponding to the strongest historical earthquakes: 1663 AD, 1860/1870 AD, 1925 AD and 1988 AD. This synchronicity over a distance reaching 220 km of several landslides supports a relationship between their triggering in the St. Lawrence Estuary and regional seismicity. The fact that as many as 9 submarine landslides appear to have been triggered by the 1663 AD earthquake indicates that this event is the strongest recorded in the last two millennia.

Keywords: 1663 earthquake, Canada, Geohazards, Geophysics, Holocene, Quebec, Paleoseismicity, Sedimentology, Submarine landslides.
Towards ocean hindcasts in coupled climate models: AMOC variability in a partially coupled model at eddying resolution.
Authors: Schulzki Tobias , Harlaß Jan , Schwarzkopf Franziska , Biastoch Arne
Published: March 2022

While forced ocean hindcast simulations are useful for a wide range of applications, a key limitation is their inability to explicitly simulate ocean-atmosphere feedbacks. As a consequence, they need to rely on artificial sea surface salinity restoring and budget corrections. Fully coupled models overcome these limitations, but lack the correct timing of variability due to much weaker observational constraints. This leads to a mismatch between forced and coupled models on interannual to decadal timescales and requires ensemble integrations.

A possibility to combine the advantages of both modelling strategies is to apply a partial coupling, i.e. nudging surface winds in the ocean component of a coupled climate model to reanalysed wind. Using an all-Atlantic nested configuration at eddying resolution, we show that partial coupling is able to simulate the correct timing of AMOC variability at all latitudes and timescales up to 5-years. Further, partial coupling excludes model drift caused by the artificial choices for restoring and simulates reasonable long term trends directly related to the applied momentum forcing. Owing to a higher impact of buoyancy fluxes, the timing of decadal variability differs between forced and partially coupled model runs.
Predicting the Bz magnetic field component from upstream in situ observations of coronal mass ejections using machine learning
Authors: Reiss Martin , Möstl Christian , Bailey Rachel , Rüdisser Hannah , Amerstorfer Ute , Amerstorfer Tanja , Weiss Andreas , Hinterreiter Jürgen , Windisch Andreas
Published: March 2022

Predicting the Bz magnetic field embedded in interplanetary coronal mass ejections (ICMEs), also called the Bz problem, is a core challenge in space weather research and prediction. We tackle this problem with a new approach by taking upstream in situ measurements of the ICME sheath region and the first few hours of the magnetic obstacle to predict the downstream Bz component. To do so, we trained a machine learning algorithm on 348 ICMEs (extracted from the open source ICMECATv2.0 catalog) observed by the Wind, STEREO-A, and STEREO-B satellites to predict the minimum value of Bz. The predictive tool was built to mimic a real-time scenario, where the ICMEs sweep over the spacecraft, which allows us to continually provide updates and improved predictions of Bz as time passes and more of the CME structure is observed. The final model, which is based on random forests, can predict the minimum value of Bz with a reasonable level of agreement compared to observations. In this presentation, we will discuss the main challenges we face in using a data-driven machine learning application to solve the Bz problem, and outline the lessons learned and future strategies for predicting and potentially mitigating the effects of ICMEs arriving at Earth.
Advancing the modeling of land use and land cover change impacts on water resources
Authors: Wagner Paul , Fohrer Nicola
Published: March 2022

Land use and land cover (LULC) change is one of the most important drivers of global change and has strong impacts on water resources. Analyzing these impacts in space and time requires appropriate monitoring and modeling approaches. In particular, interactions between land and water resources need to be better represented in modeling approaches to allow for a consistent assessment of impacts. Therefore, it is necessary to move from static to dynamic representations of LULC in hydrologic models. Moreover, modeling of LULC impacts on water resources can be further advanced by coupling LULC and hydrologic models. A coupled modeling approach enables us to consider feedback effects as well as to take management decisions into account. The benefits of a coupled modeling approach are demonstrated by coupling the hydrologic model SWAT with the LULC model CLUE-s for a meso-scale catchment in India. The coupling of the two models allows for a better representation of spatial dynamics and management decisions during a model run. Moreover, by using the example of cropland abandonment, we show the potential of the coupled modeling approach to address topics like the water-energy-food nexus and climate resilience.
Active fires during the COVID-19 lockdown period in the Llanos ecoregion, northern South America
Authors: Valencia Santiago , Marín Diver E. , Mejía-Sepúlveda Juliana , Vargas Jerónimo , Hoyos Natalia , Salazar Juan F. , Villegas Juan Camilo
Published: March 2022

Tropical savannas are the biome with the highest fire occurrences worldwide and play a key role in fire carbon emissions dynamics at regional to global scales. During the past decades, however, climate change and land use management have altered their fire regimes via fire suppression or ignition related to conservation and agricultural practices, and extreme weather conditions, among others. In particular, the ongoing COVID-19 pandemic has modified human activities in both urban and rural environments, and thus provides an opportunity to study the interactions between socio-economic and biophysical drivers of fires. Using satellite-based observations, we analyze the spatio-temporal patterns of active fires (AF, from MODIS-MCD14ML) in the Llanos ecoregion (northern South America between Colombia and Venezuela) during the COVID-19 lockdown period (mid-March to December 2020). We also examine fire carbon emissions (from GFED4s) as well as monthly precipitation (from CHIRPS), maximum temperature, and vapor pressure deficit (VPD, from TerraClimate). Our results show that 2020 was the year with the highest number of AF (>60%) and fire carbon emissions (>50%) compared to the 2001 to 2019 average. We found that these increases occur mainly during the peak of the fire season (March and April), which corresponds to the beginning of the lockdown period in Venezuela (March 17) and Colombia (March 20). Pixels (at 0.05° resolution) with significant positive AF anomalies (p<0.05) occur primarily in Venezuela and over grassland and agricultural land covers. A large proportion of these pixels interact with significant positive anomalies (p<0.05) in VPD (>70% of pixels) and maximum temperature (>50%) in March and April. Furthermore, our results highlight that the increase of AF could be associated not only with potential changes in land use management but also with weather patterns anomalies during the lockdown period in the Llanos ecoregion. 
Role of mesoscale dynamics in Southern Ocean heat uptake and storage
Authors: Zeller Mathias , Martin Torge
Published: March 2022

Mesoscale eddies play a key role in Southern Ocean dynamics, upwelling and transformation of water masses, the surface heat flux and therefore in storage of heat at deeper layers. To better understand local processes but also basin-scale implications, we apply regional ocean grid refinement to the entire region south of 28˚S in the fully coupled climate model FOCI. This two-way nesting configuration (FOCI-ORION10X) enables us to resolve the entire Southern Ocean at 0.1˚ yielding an eddy-rich simulation in this region whereas eddies are parameterized in the remainder of the global ocean running on a 0.5˚ grid. We contrast our high-resolution simulation with the non-eddying pre-industrial control run of FOCI. Heat uptake and redistribution in mean states of three pre-industrial simulations with FOCI-ORION10X are investigated: one 100 years after starting the model from rest, and two branching off from two different FOCI reference runs without and with regular open ocean deep convection in the Weddell Sea.

Net surface heat fluxes are significantly enhanced by up to 50% in the eddy-rich nested simulations compared to the non-eddying reference simulations. In our simulations, eddy kinetic energy (EKE) is largest in the Brazil–Malvinas Confluence Zone and the Agulhas Current system, regions of large upward surface heat flux, i.e. ocean heat loss. Heat uptake occurs farther south in the region of the Antarctic Circumpolar Current associated with a broad band of enhanced EKE between 45˚S and 55˚S. Explicitly simulating instead of parameterizing eddies also impacts Southern Ocean upwelling and heat convergence at mid-latitudes. We explore and quantify the associated impact on heat storage in three mean states representing different states of Southern Ocean mean temperature and bottom water volume, which affects the meridional overturning circulation strength.
Thin and thick ice in the Beaufort Sea: A new regime with enhanced mobility
Authors: Moore Kent , Steele Mike , Schweiger Axel , Zhang Jinlun , Laidre Kristin
Published: March 2022

The Arctic Ocean has seen a remarkable reduction in sea ice coverage, thickness and age since the 1980s. These changes are most pronounced in the Beaufort Sea, with a transition around 2007 from a regime dominated by multi-year sea ice to one with large expanses of open water during the summer. Here we show that during the summers of 2020 and 2021, the Beaufort Sea hosted anomalously large concentrations of thick and old ice. We show that ice advection contributed to these anomalies, with 2020 dominated by eastward transport from the Chukchi Sea, and 2021 dominated by transport from the Last Ice Area to the north of Canada and Greenland. Since 2007, cool season (fall, winter, and spring) ice volume transport into the Beaufort Sea accounts for ~45 % of the variability in early summer ice volume - a threefold increase from that associated with conditions prior to 2007.   Impacts of these changes are likely to occur on stressed regional ice-dependent ecosystems.
The Impact of Zonal Jets on the Atlantic Oxygen Minimum Zones 
Authors: R. Calil Paulo H.
Published: March 2022

Oxygen is an essential component of the ocean biogeochemistry.  Relatively small variations in its content may have a significant impact on ocean productivity, biodiversity and fisheries and thus affect ocean health and ecosystem services.  Over the last decade, several studies have shown that regions with low oxygen concentrations are expanding over the world's oceans, a phenomenon which has been termed ocean deoxygenation. These changes are driven by a combination of anthropogenic climate change and the natural variability of the ocean. As climate change warms the upper ocean it reduces oxygen solubility,  increases upper ocean stratification and thus reduces oxygen mixing as well as induces changes in respiration rates. Disentangling the natural and anthropogenically-induced oxygen variability requires the use of models as prognostic or diagnostic tools, as they can be forced with different conditions which may or may not include the effects of climate change and allow a detailed examination of specific processes. In this work,  we compare two basin-scale coupled physical-biogeochemical simulations of the Tropical Atlantic ocean at different horizontal resolutions and show that more robust zonal jets at intermediate depths in the higher resolution simulation have a major impact on the overall structure of the North and South Atlantic OMZs by limiting their westward extent and supplying oxygen to the OMZ core regions between 300 m and 500 m. 
Data-driven stochastic model of multi-scale climate dynamics
Authors: Feigin Alexander , Gavrilov Andrey , Loskutov Evgeny
Published: March 2022

In this work, we demonstrate the performance of a new data-driven method [1] for modeling cross-interacting processes with different time scales represented by time series with different sampling steps. The model is a generalization of a nonlinear stochastic model of evolution operator based on neural networks, designed for the case of time series with constant sampling step, and has complex structure. First, it describes each process by its own stochastic evolution operator with its own time step. Second, it considers possible nonlinear connections within each pair of processes in both directions. These connections are parameterized asymmetrically, depending on which process is faster and which process is slower. They make this model essentially different from the set of independent stochastic models constructed individually for each time scale. All evolution operators and connections are trained and optimized using Bayesian framework, forming a multi-scale stochastic model. 
We demonstrate the capabilities of the model using two climate data examples. The first example is a climate spatio-temporal data generated by a global climate model running in the middle 19th century external conditions. A second example is spatially distributed reanalysis data describing current climate evolution. In both examples we investigate first how correctly the multiscale model reconstructs the individual evolution of both subsystems, and second whether it reveals the connection between processes that is not captured by models built individually for each process.
The work was supported by the Russian Science Foundation (Grant No. 20-62-46056).
[1] Gavrilov et al. (2021). Data-driven stochastic model for cross-interacting processes with different time scales, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4199.