bluuebunny/crossref_metadata_2025 huggingface dataset:
Which properties of adsorbed droplets can describe heterogeneous nucleation on carbonaceous surfaces? Insights from molecular simulations and theoretical models.
Authors: Lbadaoui-Darvas Mária , Nenes Athanasios , Takahama Satoshi , Laaksonen Ari
Published: March 2022

Heterogeneous nucleation of cloud droplets or ice occurs on insoluble aerosol when the supersaturation of water vapor exceeds 100%. It is one of the least well understood processes in the climate system [Seinfeld et. al., PNAS, 2016]. The propensity of the different types of particles to nucleate cloud or ice droplets is affected by molecular scale chemical and topological properties of their surface [Kanji et. al., Meteor. Mon., 2017]. Heterogeneous nucleation is commonly represented in climate models by the classical nucleation theory (CNT) [Fletcher, J. Chem. Phys., 1958], whose only tunable input parameter is the contact angle, which does not allow for the inclusion such details. In this work we use the example of soot to demonstrate that a single contact angle, used as a thermodynamic parameter, is an ambiguous descriptor of the hydrophilicity - and therefore of the heterogeneous nucleation efficiency - of a surface. We also show that the adsorption nucleation theory (ANT) [Sorjaama, Atmos. Chem. Phys. 2007], in which the contact angle serves as geometric parameter that links the droplet shape to the amount water adsorbed at the surface, can account for molecular scale surface properties.

We perform molecular dynamics simulations of water nanodroplets on model graphene and soot surfaces whose hydrophilicity is tuned by A) uniformly scaling the interaction energy between the surface and droplet and B) by adding hydroxyl groups in different concentration and topology. We estimate the mean equilibrium contact angle of the droplets, and we present spatial distributions of local contact angles as novel and unusual approach to describe the real shape of nanodroplets, which strongly deviate from the idealized assumption of a spherical cap and fluctuate in time.

The average contact angle is a good descriptor of the hydrophilicity only in the case of type A systems, for which, in accordance with previous simulation results, we observe a linear relationship between the contact angle the surface hydrophilicity expressed as pairwise ƐLJ parameter between the water and the surface. For the chemically and topologically heterogeneous type B systems we could not identify any significant correlation. Since the same mean contact angle can correspond to very different surfaces, CNT is not expected to differentiate between their heterogeneous nucleation activity.  The contact angle distributions on the other hand provide a unique description of the droplet shape for each of the systems. The distributions are bimodal for type A and trimodal for type B systems, with the marked differences in the weight and position of the hydrophobic peak. These distributions are however strictly geometrical properties of the droplet, and hence can only be used in the framework provided by ANT.
Spectral analysis of the Southern Hemisphere atmospheric variability to assess the role of baroclinic instability in seasonal forecasts
Authors: Trentini Laura , Dal Gesso Sara , Dell'Aquila Alessandro , Petitta Marcello
Published: March 2022

Baroclinic instability in the mid-latitudes is a significant component of the climate system, as it is associated with the meridional transport of a large amount of energy and momentum. Hence, the ability of climate models to correctly predict the properties of atmospheric circulation in that latitudinal band is a very important requirement. This study aims to estimate the power content of the atmospheric phenomena typical of mid-latitudes, such as baroclinic perturbations, and to understand how seasonal forecasts can be practically used to assess energy transfer in the atmosphere. We compare the Southern Hemisphere mid-latitude winter variability of the long-range forecasting system SEAS5 with the ERA5 reanalysis. Both datasets are produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). The analysis is carried out by computing the Hayashi spectra of the 500-hPa geopotential height field. Both the reanalysis and the seasonal forecast show a series of peaks in the spectral region of eastward-traveling waves, which corresponds to the high frequency-high wavenumber domain. We quantify the amount of energy released from the atmosphere by calculating the Baroclinic Amplitude Index. Results suggest that the seasonal forecasts correctly reflect the variability of the geopotential height power spectra in the Southern Hemisphere, with some minor discrepancies related to the sub-daily variability, which is not correctly discriminated. However, the energy associated with the baroclinic activity is well represented by the seasonal forecast in the Southern Hemisphere, where the orographic effect is negligible compared to the Northern Hemisphere. This work is carried out as part of the European FOCUS-Africa project, which develops innovative and sustainable climate services in the Southern African Development Community (SADC) region.
Water table depth dynamics derived from optical remote sensing data in northern peatlands
Authors: Burdun Iuliia , Bechtold Michel , Komisarenko Viacheslav , Lohila Annalea , Humphreys Elyn , Desai Ankur R. , Nilsson Mats B. , Tuittila Eeva-Stiina , De Lannoy Gabrielle , Uuemaa Evelyn , Rautiainen Miina
Published: March 2022

Water table depth (WTD) is one of the key factors that affect the carbon balance in peatlands. Optical remote sensing can detect WTD indirectly through the estimation of surface moisture. In peatlands, WTD and surface moisture conditions are closely related through the strong capillary connection in the topmost peat layer. We took advantage of this strong connection and calculated the OPtical TRApezoid Model (OPTRAM) that relies on the assumption that short-wave infrared reflectance represents the surface moisture conditions. OPTRAM was calculated based on Sentinel-2 MSI and Landsat 8 OLI over selected northern peatlands in Finland, Sweden, Canada, the USA, and Estonia. This is the first study in which the advantages and shortcomings of OPTRAM estimation from Sentinel-2 MSI and Landsat 8 OLI data were discussed. We calculated OPTRAM in two ways: (i) using a manual parametrisation and (ii) utilising a recently developed automatic parameterisation in Google Earth Engine. Further, we analysed the impact of these two parameterisations on OPTRAM performance in various peatlands. Our findings provide an important insight into the global applicability of OPTRAM for monitoring moisture conditions in northern peatlands.
Evaluation of CMIP5 and CMIP6 global climate models in the Arctic and Antarctic regions, atmosphere and surface ocean
Authors: Agosta Cécile , Kittel Christoph , Amory Charles , Edwards Tamsin , Davrinche Cécile
Published: March 2022

Large efforts are engaged to model climate-ice sheet interactions in order to estimate Antarctic and Greenland ice sheets’ contribution to sea level in the next decades to centuries. Here we present a first-order evaluation of CMIP5 and CMIP6 climate models over both polar regions. We focus on large-scale atmospheric fields and surface ocean variables only. Our goal is to provide a first overview of climate model biases in polar regions, in order to use their outputs on an informed basis. We particularly target the use of climate model outputs for forcing ice sheet models and regional atmospheric models.

We consider 9 (non-independent) variables : 850 hPa and 700 hPa annual and summer temperature, annual integrated water vapor, annual sea level pressure, annual 500hPa geopotential height, summer sea surface temperature, and winter sea ice concentration; over the Arctic (> 50°N) and the Antarctic (<40°S) regions. We use the ERA5 reanalysis as a reference, but we also include 5 other reanalyses in the intercomparison in order to estimate uncertainty coming from this choice. We define two sets of metrics. The first set of metrics, called “scaled rmse”, is the spatial root mean square error (RMSE) of time-mean variables for each region, that we divide by the median RMSE among all CMIP models. The second set of metrics, called “implausible fraction”, is the portion of the region where the difference between time-mean CMIP model and time-mean ERA5 is greater than three times the local interannual standard deviation. We find a strong relationship between the two sets of metrics. In addition, using the implausible fraction, we find that CMIP variables are significantly more implausible in the Antarctic than in the Arctic. It might be because of badly resolved processes or because of higher decadal variability in the South. Further work should include estimates of decadal variability in the implausibility computation.
Reconstructing Pyroclastic Currents’ Source and Flow Parameters from Deposit Characteristics and Numerical Modelling: The Pozzolane Rosse Ignimbrite case study (Colli Albani, Italy)
Authors: Calabrò Laura , Esposti Ongaro Tomaso , de' Michieli Vitturi Mattia , Giordano Guido
Published: March 2022

Pyroclastic currents (PCs) are composed of hot mixtures of gas and pyroclastic particles, which travel at moderate to very high speed (tens to hundreds of m/s), under the effect of their density contrast with the surrounding atmosphere. They can be flowing over obstacles with ease but their pathway is often controlled by the topography they flow over. These characteristics make them one of the most dangerous and inaccessible to direct study, natural phenomena. For this reason, the use of numerical modeling could be one of the most useful tools to provide key quantitative information about their internal dynamics. In this study, we used the available data about Pozzolane Rosse ignimbrite (Colli Albani, Italy) caldera-forming, - 460 ka, 63 km3 DRE - to model source and flow dynamics with a depth-averaged model for inertial PCs. Numerical simulations allowed us to test the effects of 1) atmospheric air entrainment, by varying the Richardson number (), 2) the initial flow thickness, 3) initial flow velocity, 4) grain-size distribution, and 5) mixture density on PCs runout and thickness decay pattern. Model validation was performed by comparing i) model runout and field data; ii) the thickness of the deposit compared to the thickness of the model output with the distance; iii) the mass fractions of the different grain size classes for the actual deposit compared to the model output. Several simulations were carried out considering i) the influence of parameters h and v; ii) the density; iii) the temperature and iv) the topography. The results allowed us to understand and quantify the first-order variables that characterize flow propagation (runout) and thickness decay pattern, indicating that the depth-averaged model may be suitable to represent the dynamics of large PCs, such as those of the Pozzolane Rosse.
Effects of extreme melt events on the Greenland ice sheet
Authors: Beckmann Johanna , Winkelmann Ricarda
Published: March 2022

Over the past decade, Greenland has experienced several extreme melt events, the most pronounced ones in the years 2010, 2012 and 2019. With progressing climate change, such extreme melt events can be expected to occur more frequently and potentially become more severe. So far, however, projections of ice loss and sea-level change from Greenland typically rely on scenarios that only take gradual changes in the climate into account. 
Here we investigate the effect of extreme melt events on the ice dynamics and overall mass balance of the Greenland Ice Sheet in simulations using the Parallel Ice Sheet Model (PISM). While the extremes generally lead to thinning of the ice sheet by enhanced melting, they partly also decrease the overall ice surface velocities due to a reduced driving gradient. In our simulations, we find that taking extreme events into account leads to additional ice loss compared to the baseline scenario without extremes. We find that the sea-level contribution from Greenland could increase by up to 45 cm by the year 2300 if severe extreme events are considered in future projections. We conclude that both changes in the frequency and intensity of extreme events need to be taken into account when projecting the future sea-level contribution from the Greenland Ice Sheet.
Plasma transport across high latitudes
Authors: Pokhotelov Dimitry , Fernadez-Gomez Isabel , Borries Claudia
Published: March 2022

Plasma anomalies appear at high latitudes, extending across the polar cap as a tongue of ionisation and/or polar patches. Physical mechanisms responsible for plasma uplifts and transport are investigated using global ionospheric circulation models driven by parameterised high-latitude plasma convection models. Various convection models will be considered, including the models based on satellite data, SuperDARN radar data, and data assimilation models. Relative contributions from electrodynamic plasma transport and neutral wind forcing are assessed. The simulations are compared with GNSS and radar observations. The results are discussed in the context of space weather modelling and scintillation environment modelling at high latitudes.
Numerical modelling of strain localization by anisotropy evolution during 2D viscous simple shearing
Authors: Halter William , Macherel Emilie , Duretz Thibault , Schmalholz Stefan M.
Published: March 2022

Strain localization and associated softening mechanisms in a deforming lithosphere are important for subduction initiation or the generation of tectonic nappes during orogeny. Many strain localization and softening mechanisms have been proposed as being important during the viscous, creeping, deformation of the lithosphere, such as thermal softening, grain size reduction, reaction-induced softening or anisotropy development. However, which localization mechanism is the controlling one and under which deformation conditions is still contentious. In this contribution, we focus on strain localization in viscous material due to the generation of anisotropy, for example due to the development of a foliation. We numerically model the generation and evolution of anisotropy during two-dimensional viscous simple shear in order to quantify the impact of anisotropy development on strain localization and on the effective softening. We calculate the finite strain ellipse during viscous deformation. The aspect ratio of the finite strain ellipse serves as proxy for the magnitude and evolution of anisotropy, which determines the ratio of normal to tangential viscosity. To track the orientation of the anisotropy during deformation we apply a director method. We benchmark our implementation of anisotropy by comparing results of two independently developed numerical algorithms based on the finite difference method: one algorithm employs a direct solver and the other a pseudo-transient iterative solver. We will present results of our numerical simulations and discuss their application to natural shear zones.
Impact of tropical convection on upper tropospheric cirrus in high resolution DYAMOND simulations
Authors: Corko Karol , Burkhardt Ulrike
Published: March 2022

The high-resolution DYAMOND simulations resolve much of the cloud relevant dynamics and cause a large improvement in the structure and diurnal cycle of clouds and precipitation. Nevertheless, from DYAMOND simulations we know that cloud properties can vary significantly even in high-resolution simulations. We focus on evaluating and if possible constraining ice cloud processes in the tropics, an area that should particularly benefit from the increased resolution because deep convection is resolved and controls the tropical upper tropospheric water budget. We analyse not only the horizontal distribution of IWP but also the cloud phase and cloud vertical structure as they are crucial to Earth’s radiation budget.

When comparing the high-resolution global simulations performed within the DYAMOND project among each other and with passive remote sensing data and ERA5 reanalysis we find that the horizontal distribution of ice water path (IWP) varies significantly. In order to understand better those differences, we analysed the connection between the simulated vertical velocity and the total IWP, and the water path of the individual hydrometeors. While the PDF of tropical vertical velocity simulated by the different models is quite similar, the total ice water path connected with those vertical velocities varies strongly. In most models, high vertical velocities are connected with significantly higher IWP than liquid water path (LWP) except in the ICON simulations which simulates similarly large increases in IWP and LWP. Most models simulate large increases in larger ice hydrometeors for large vertical velocities while FV3 simulates also large increases in ice water connected with deep convection. Differences in cloud phase e.g. when comparing NICAM and ICON simulations are connected with different vertical distributions of the condensate with NICAM IWC reaching higher atmospheric levels than the ICON IWC. We attempt to constrain the vertical distribution using active remote sensing data. 
Environmental resilience in rural Wales (UK): the role of art in scientist-artist-farmer engagement 
Authors: Follett Elizabeth , Turnbull Penelope , Davis Lorna , Wilson Catherine , Cable Jo
Published: March 2022

Farmers manage 88% of Wales’ land area, maintaining and enhancing the natural environment for aesthetic enjoyment and wellbeing of the wider population. Their provision of ecosystem services ranges from habitat creation and management to water storage to reduce flood impacts and carbon capture. The benefits of sustainable farming in the UK have gained particular relevance as climate change is expected to increase summer storm intensity and temperature, with increased sediment runoff and reduced river water quality. To improve understanding of Welsh farmers’ perspectives on sustainable farming actions and develop targeted information delivery, we discussed decision-making processes towards sustainable farming actions and suggestions for the future of Welsh farming with farmers in three catchments (Monmouthshire, Pembrokeshire, and Anglesey).  Outputs presenting information on sustainable farming actions were revised following participant feedback, with revisions including watercolour drawings of Welsh farmland with sustainable farming actions, which demonstrated implementation in the Welsh landscape without identifying specific sites. A broader understanding of the tensions experienced by farmers coping with climate change and economic pressures as understood through discussion with farmer-participants was communicated through a mosaic sculpture ‘The Farmer’s Voice,’ which was co-designed with farmers and scientists, together with a professional artist, including incorporation of anonymised phrases from participants in Welsh and English. An initial series of possible designs was created following initial interviews, and the final design was chosen after consultation with farmer-participants. Anonymised feedback on sustainable farming and climate change from further workshops was used to inform more detailed technical drawings. In particular, the role of design and management of tree planting schemes and the historic role of farmers in caring for the environment through coppicing and hedgerow maintenance emerged as significant themes during the project. Technical drawings were approved by farmer-participants, who also suggested inclusion of phrases in Welsh and English. The final sculpture, co-designed in partnership with farmers, scientists, and a professional artist, was created from copper wire, recycled glass, and Welsh slate, representing an abstract tree demonstrating farmer resilience through and need for support and nourishment in the face of climate change. The sculpture will be exhibited at the Royal Welsh Show 2022.
Regional scale evaluation of marine properties as simulated by CMIP6 Earth System models  for contemporary climate conditions
Authors: Butenschön Momme , Tjiputra Jerry , Lovato Tomas , Negrel Jean
Published: March 2022

Environmental changes resulting from anthropogenic forcings have significant implications at regional and coastal scales impacting considerably on a variety of key ecosystem services.
While the capacity to understand, quantify and predict these impacts is essential for a consolidated implementation of adaptation and mitigation strategies, the information available on the environmental changes is often insufficient. Extensive datasets from global projections exist from the CMIP initiatives that provide a wealth of information including crucial estimates of uncertainty and likelihood but are mostly assessed at global or basin level delivering broad-scale information that is often less relevant or prone to large uncertainties at the regional service level. While some regional information exists deriving from individual dynamically downscaled simulations, these are mostly driven by the effort of individual institutions  and hence lack robust estimates of uncertainty and are prone to significant biases deriving from the applied boundary forcings, which are often chosen in an opportunistic manner.

Here we present an attempt to overcome some of these short-comings pursued in the CE2COAST project (https://www.ce2coast.com) providing a systematic assessment of a suite of indicators of multiple ocean pressures from CMIP6 simulations validated at regional level for selected European Seas and the Humbolt Current. The outcome presents valuable information in itself on the spread of model performances in CMIP6  at regional level and is highly relevant as baseline and benchmark for regional downscaling efforts. It highlights that there is no single global model that will fit-for-purpose for downscaling in all regions or for addressing all ocean pressures.
The future carbon footprint of materials as a bottleneck for the transition to Net-Zero Emissions – case study on France
Authors: Teixeira Antoine , Lefèvre Julien
Published: March 2022

Paris climate agreement has been a major step forward to limit the global mean temperature rise to below 1.5°C above pre-industrial levels. For many countries, it has led to adopt Net-Zero GHG Emissions (NZE) targets by mid-century. Such objectives imply renewing much existing infrastructures and equipment through low-carbon investments in key sectors (buildings, transport, and power supply). However, there is a risk to overshoot the objectives due to base carbon-intensive materials (steel, cement, etc.). Indeed, material demand is already expected to double by mid-century following economic trends. Deploying intensively low-carbon infrastructure and technologies is expected to increase material demand even more. The size of this surplus is unclear as most energy prospects neglect the feedback between the low-carbon transition and material needs. In addition, most countries restrict their NZE targets to territorial emissions, whereas a carbon footprint approach is essential to account for carbon linkage and industrial relocation toward more carbon-intensive countries. Also, the potential for a fast transition to zero-carbon industrial processes and materials as required is still uncertain, all the more in developing countries producing most materials. The design of stringent climate policy needs a clearer vision of the role of materials in the low-carbon transition to prioritizing mitigation actions.

Our study aims to quantify the link between GHG emissions, low-carbon investments, and the demand for materials. We develop an Input-Output model called MatMat designed (i) to integrate various sets of expertise about low-carbon scenarios and (ii) to track the role of investment demand and material supply in the evolution of the carbon footprint. We apply our method to the french governmental NZE scenario and global mitigation scenarios until 2050. By disentangling key drivers impacting GHG emissions embodied in materials, we show that the carbon footprint of materials could offset national NZE targets due to (i) the indirect material demand embodied in imports and (ii) the potential delay in decarbonizing the material production compared to other sectors, especially abroad. To relieve the material bottleneck for the transition to NZE strategy, we recommend (i) developing material efficiency and circular economy policies, (ii) relocating low-carbon industrial productions, and (iii) supporting imports of clean industrial products at the national level.
Cellular Automata-based high-resolution hydrological modeling for urban digital water information
Authors: Noh Seong Jin , Lee Eunhyung , Choi Hyeonjin , Lee Garim , Kim Sanghyun
Published: March 2022

In this study, we propose and evaluate a Cellular Automata (CA)-based high-resolution hydrological model for an urban digital water information framework. Pluvial flooding in the extreme events and water balance in the non-rainy seasons are usually simulated by different modeling frameworks hampering holistic understandings of the complex water cycle in the urbanized areas. However, for smart water systems such as digital twins or multiverse, street-resolving, high-fidelity water information is required regardless of types of hydrologic events. To provide seamless urban water information on the digital world such as digital twins, Cellular Automata, a rule-based machine learning technique, is adopted and extended to simulate continuous hydrological variables such as inundation depth, infiltration, soil water content, and evapotranspiration in the complex urbanized domain. A proto-type CA model is implemented in the Oncheon-Cheon catchment in Busan, South Korea, which is highly urbanized and vulnerable to pluvial flooding. In the presentation, we discuss advances and challenges in machine learning-based integrated urban water modeling.
Sensitivity of regional monsoons to idealised equatorial volcanic eruption of different sulfur emission strengths
Authors: D'Agostino Roberta , Timmreck Claudia
Published: March 2022

The impact of volcanic forcing on tropical precipitation is investigated in a new set of sensitivity experiments within the Max Planck Institute Grand Ensemble framework. Five ensembles are created, each containing 100 realizations for an idealized “Pinatubo-like” equatorial volcanic eruption with emissions covering a range of 2.5 - 40 Tg sulfur (S). The ensembles provide an excellent database to disentangle the influence of volcanic forcing on monsoons and tropical hydroclimate over the wide spectrum of the climate's internal variability. Monsoons are generally weaker for two years after volcanic eruptions and their weakening is a function of emissions. However, only a stronger than Pinatubo-like eruption (> 10 Tg S) leads to significant and substantial monsoon changes, and some regions (such as North and South Africa, South America and South Asia) are much more sensitive to this kind of forcing than the others. The decreased monsoon precipitation is strongly tied to the weakening of the regional tropical overturning. The reduced atmospheric net energy input at the ITCZ due to the volcanic eruption and, under negligible changes in the gross moist stability, requires a slowdown of the circulation as a consequence of less moist static energy exported away from the ascent.
What control the sediment export in the ultimate deep-sea sink : the example of the Zambezi submarine fan (Mozambique channel)
Authors: Robin Cecile , Guillocheau Francois
Published: March 2022

Deep-sea fans are the ultimate area of sediment deposition along the source-to-sink systems. Since the definition of transport efficiency by Mutti (1979), i.e. the ability of gravitary flows over at least hundreds of thousand years to transport sediments far off the slope, little attention was paid to the factors (tectonics, eustasy, sediment delivery at the top of the slope) controlling this efficiency. We here test the possible controls on the transport efficiency of submarine fans looking for the distribution of both sedimentary facies and mainly the distance of the upstream part of the lobes from the slope and the sediment volumes.

This study was performed on the Zambezi deep-sea fan and its upstream delta since 160 Ma. The Zambezi catchment and little Madagascan feeders experienced several uplifts (Southern African Plateau, East African Dome, Madagascar Plateau) and two drastic climate (precipitation) changes between semi-arid and very humid conditions. The used data are seismic lines calibrated on dated wells. We defined depositional sequences that provided time-lines for measuring siliciclastic sediment volumes. Facies mapping was based on seismic reflectors characteristics (geometry, attributes).

The first obvious control is the topography, mainly in the early stage of the ocean opening, but also the growth of topographic ridges isolating ponded basins. The main factor seems to be an increase of the siliciclastic sediment flux due to uplift of the upstream catchment, i.e. at the apex of the sink that is transferred, at the scale of hundreds of thousand years, directly to the deep-sea fan. This is supported by the effect of the two steps uplift of the southern African Plateau (90-80 and 40-30 Ma) and of the Eat African Dome. Climate and eustatic changes are clearly second order processes. We tested the buffer effect of the upstream delta and associated ponded basins.
Calcification recovery after exposure to ocean acidification conditions - results from culture experiments and geochemical signature
Authors: Charrieau Laurie , Nagai Yukiko , Kimoto Katsunori , Dissard Delphine , Below Béatrice , Fujita Kazuhiko , Toyofuku Takashi
Published: March 2022

Ocean acidification is a consequence of current anthropogenic climate changes. The concomitant decrease in pH and carbonate ion concentration in sea water may have severe impacts on calcifying organisms, such as foraminifera. The composition of the shells (called tests) of these cosmopolitan unicellular organisms roughly reflects environmental conditions at the calcification time, and they can fossilise. Thus, foraminifera are widely used as proxy for past environmental parameters, including for the carbonate system.

The aim of this study was to evaluate the effects of varying pH on calcification and test geochemistry of the symbiont-bearing species Peneroplis spp. We performed culture experiments to study their resistance to ocean acidification conditions, as well as their calcification recovery once placed back under open ocean pH 7.9.

After 3 days at pH 6.9 and dark conditions, strongly decalcified specimens were observed, with the inner organic lining clearly appearing. These specimens were still alive, as attested by cytoplasm streaming. Some of the specimens were then placed back at pH 7.9, in light/dark conditions. After one month, a new calcification phase started for the majority of the specimens, by addition of new chambers. The trace elements concentrations of the new calcite were analysed by LA-ICPMS. The incorporation of B and Zn appeared to have been rapidly impacted by changes in the culture conditions. Moreover, the newly formed chambers were most of the time abnormal, and the general structure of the tests was altered, which has potential impacts on reproduction and in situ survival of the specimens. In conclusion, if symbiont-bearing foraminifera show some resistance and recovery abilities to short term lowered pH conditions, they will remain strongly affected by ocean acidification.
An individual-based tree data set on forest structure in Siberia‘s remote north-east
Authors: Miesner Timon , Herzschuh Ulrike , Pestryakova Luidmila A. , Wieczorek Mareike , Zakharov Evgenii S. , Kolmogorov Alexei I. , Kruse Stefan
Published: March 2022

The permafrost-underlain deciduous forests of north-east Siberia form a unique ecosystem that is experiencing pressure from global warming, in the form of permafrost thaw, wildfires of increasing intensity and frequency, and drought stress. Even though it covers millions of square kilometers and could become an important driver in the global climate system with the vast amounts of carbon stored in its soil and plants, there is relatively little knowledge on it because of its remoteness.

In a series of expeditions between 2011 and 2021, a consortium of researchers from the North East Federal University Yakutsk (NEFU) and the Alfred Wegener Institute (AWI) surveyed more than 160 forest sites in Yakutia and at the northern treeline, in Chukotka and the Taymir Peninsula. These include intact larch forest and forest tundra sites, as well as different stages of succession after wildfire disturbance. We observed species, height and vitality status for over 39,000 trees, of which around 2000 were inventorized in a more detailed manner, including diameters and crown diameters.

We will present analyses of individual-based metrics necessary for upscaling the forest inventory to the plot level. Additionally, we compared our ground inventory data with freely available remote sensing products to evaluate their performance in predicting forest structure on the small scale. The comparison yielded large errors, as the forest metrics vary strongly on the local scale, thereby emphasizing the need for ground data like we collected.

This dataset gives a unique insight into the forest structure of this remote area, and can be used for a variety of purposes.
Sky-high opportunities deep underground – Callio Lab research centre 
Authors: Puputti Julia , Joutsenvaara Jari , Kotavaara Ossi , Niinikoski Eija-Riitta
Published: March 2022

One of the northernmost deep underground laboratories (DULs) in Europe can be found at Callio Lab, operating at the Pyhäsalmi Mine in Finland. What began as purely an underground physics centre in the early 2000s has been expanded into an international, multi- and transdisciplinary research centre known as Callio Lab. Its activities are coordinated by the University of Oulu Kerttu Saalasti Institute (KSI). Callio Lab is a founding member of the European Underground Laboratories Association, a part of the DULIA network, and a part of the national FIN-EPOS research infrastructure network. [1].

With underground mining ending in spring 2022, Callio Lab is a key element of the repurposing activities conducted under the CALLIO - Mine for Business concept. CALLIO will continue activities at the mine-site until at least 2025 [2]. Owing to the unique environment and circumstances, Callio Lab research can be conducted underground at seven deep underground laboratories found at various depths, as well as above-ground [3].

Callio Lab has conducted and facilitated research in fields ranging from particle physics and geosciences to underground food production and remote sensing. The operating environment presents versatile opportunities also in the study of circular economy, muography, and space and planetary sciences. Notable projects at Callio Lab have included the international EIT RM funded MINETRAIN, Interreg Baltic Sea Region funded BSUIN, and H2020 funded GoldenEye projects [4-6].

The operating environment at Callio Lab is well-known due to characterisation activities conducted during previous projects, datasets acquired from decades of research, and an extensive microseismic monitoring network. Callio Lab has a logistically ideal location, and the DULs themselves can be accessed via the incline tunnel or elevator shaft. The existing infrastructure and facilities, in-depth understanding and application of underground risk management and conditions, and well-established operating methodology ensures Callio Lab the capacity to successfully operate and facilitate a wide range of activities. [1,3].

[1] Callio Lab, www.oulu.fi/en/callio-lab, 11 Jan 2022

[2] Mine for Business – Callio – Pyhäjärvi, Finland, www.callio.info, 1 Jan 2022

[3] Callio Lab – Underground Center for Science and R&D, www.calliolab.com, 11 Jan 2022

[4] MINETRAIN, www.minetrain.eu, 8 Jan 2021

[5] Baltic Sea Underground Innovation Network, www.bsuin.eu, 11 Jan 2022

[6] GoldenEye EU H2020 funded project, www.goldeneye-project.eu, 11 Jan 2022
Seismic Vulnerability of a Slender Intact Stalagmite standing in a Karstic Cave
Authors: Gribovszki Katalin , Bońkowski Piotr A. , Jaworski Marcin A. , Zembaty Zbigniew
Published: March 2022

Recently, it has been argued that natural, intact stalagmites in caves give important constraints on seismic hazard since they have survived all earthquakes over their (rather long) life span. For this reason, applying detailed modelling methodologies to study the seismic motion of speleothems has special significance. Here we present a stalagmite-based study from the Little Carpathians of Slovakia, Plavecka priepast cave.

The seismic response of stalagmite is computed using a robust, a fully three-dimensional, Finite Element Method model calibrated from free vibration records by Hilbert-Huang modal extraction. It is demonstrated that the stalagmite vibrations consist of pairs of closely coupled flexural natural modes with a negligible role of vertical excitations.

An underground record of a moderate earthquake was applied to excite low intensity seismic vibrations. Particular attention was paid to observing the role of the vertical component of seismic ground motion. It is concluded that the failure mode of the stalagmite is driven by flexural vibrations. The safety margins of this stalagmite were assessed by analysing the tensile stress map from the seismic response computations. The location of the breaking point of the stalagmite is a result of a balance between the overturning bending moment and variations of horizontal cross-sections with height. The ultimate peak velocity of excitations equalling 3.2 mm/s is estimated.

The used input data and the animations are available on these web pages:

https://z.zembaty.po.opole.pl/SupplementaryStalagmite3Dview.html

https://z.zembaty.po.opole.pl/SupplementaryStalagmite.html
Reconstructing the Dynamics of the Outer Electron Radiation Belt by Means of the Standard and Ensemble Kalman Filter With the VERB-3D Code
Authors: Castillo Tibocha Angelica M. , de Wiljes Jana , Shprits Yuri Y. , Aseev Nikita A.
Published: March 2022

Reconstruction and prediction of the state of the near-Earth space environment is important for anomaly analysis, development of empirical models, and understanding of physical processes. Accurate reanalysis or predictions that account for uncertainties in the associated model and the observations, can be obtained by means of data assimilation. The ensemble Kalman filter (EnKF) is one of the most promising filtering tools for nonlinear and high dimensional systems in the context of terrestrial weather prediction. In this study, we adapt traditional ensemble-based filtering methods to perform data assimilation in the radiation belts. By performing a fraternal twin experiment, we assess the convergence of the EnKF to the standard Kalman filter (KF). Furthermore, with the split-operator technique, we develop two new three-dimensional EnKF approaches for electron phase space density that account for radial and local processes, and allow for reconstruction of the full 3D radiation belt space. The capabilities and properties of the proposed filter approximations are verified using Van Allen Probe and GOES data. Additionally, we validate the two 3D split-operator Ensemble Kalman filters against the 3D split-operator KF. We show how the use of the split-operator technique allows us to include more physical processes in our simulations and is a computationally efficient data assimilation tool that delivers an accurate approximation of the optimal KF solution, and is suitable for real-time forecasting.
From the Izu-Bonin to the north of Hokkaido : how did the M9.0 Tohoku earthquake affect the Pacific plate seismicity ?
Authors: Gardonio Blandine , Marsan David , Durand Stéphanie , Schubnel Alexandre
Published: March 2022

The last twenty years have seen a number of large, devastating earthquakes on subduction zones. In many ways, the M9.0 Tohoku-oki earthquake was bewildering for the seismological community. It occurred on a previously identified coupled area but ruptured a larger zone than expected and, above all, the large amount of near-trench coseismic slip was a surprise.

Because Japan is one of the best area instrumented in the world, the 2011 Mw 9.0 Tohoku-oki earthquake is one of the world's best-recorded ruptures. Many studies have analyzed with great details the pre-seismic, co-seismic and post-seismic phases of the Tohoku earthquake. Researchers also focused on the triggering of on-land seismicity following the mega-thrust earthquake. However, no study zoom out and considered the consequences of this earthquake on the Pacific plate in this area.

 

In this study, we analyzed the Japanese Meteorological Agency seismic catalog over ten years of data to assess the consequences of such large mega-thrust earthquake over the Pacific plate from the Izu-Bonin area to the north of Hokkaido island. We studied the seismicity from 0 to 700km depth, taking advantage of one of the most complete subduction zone catalogue.

Our results show that the seismic rate south of Japan experienced a decrease at the time of Tohoku about 30% and an increase of 20% underneath the Hokkaido island. The subduction zone that is downdip Tohoku doesn’t seem affected by the megathrust earthquake. While it is difficult to understand and to model such large scale effects of the Tohoku earthquake on the Pacific plate, we think it is primordial to observe and detail them with precision.
Stress evolution and slip deficit on the North Anatolian Fault (Turkey) in the Marmara Sea: insights from paleoseismicity, seismicity and geodetic data
Authors: Meghraoui Mustapha , Toussaint Renaud , Aksoy Murat Ersen
Published: March 2022

The North Anatolian Fault experienced large earthquakes with 250–400 years recurrence time. In the Marmara Sea region,
the 1999 (Mw=7.4) and the 1912 (Mw =7.4) earthquake ruptures bound the Central Marmara Sea fault segment. Using
historical-instrumental seismicity catalogue and paleoseismic results (≃ 2000-year database), the mapped fault segments, fault
kinematic and GPS data, we compute the paleoseismic-seismic moment rate and geodetic moment rate. A clear discrepancy
appears between the moment rates and implies a signifcant delay in the seismic slip along the fault in the Marmara Sea. The
rich database allows us to identify and model the size of the seismic gap and related fault segment and estimate the moment
rate defcit. Our modelling suggest that the locked Central Marmara Sea fault segment (even including a creeping section)
bears a moment rate defcit 6.4 × 1017 N.m./year that corresponds to Mw ≃ 7.4 for a future earthquake with an average
≃ 3.25 m coseismic slip. Taking into account the uncertainty in the strain accumulation along the 130-km-long Central fault
segment, our estimate of the seismic slip defcit being ≃ 10 mm/year implies that the size of the future earthquake ranges
between Mw=7.4 and 7.5.

Reference:

[1] Meghraoui, M., Toussaint, R. & Aksoy, M.E. The slip deficit on the North Anatolian Fault (Turkey) in the Marmara Sea: insights from paleoseismicity, seismicity and geodetic data. Med. Geosc. Rev. 3, 45–56 (2021). https://doi.org/10.1007/s42990-021-00053-w
A mid-20th century benchmark estimate of global vegetation biomass carbon stocks 
Authors: Bhan Manan , Meyfroidt Patrick , Gingrich Simone , Matej Sarah , Erb Karl-Heinz
Published: March 2022

Vegetation biomass carbon stocks play a vital role in the climate system, but the analysis of long-term carbon budgets is hindered by the lack of benchmarked estimates from the 20th century. Here, by integrating inventory-based information on land use and carbon densities in a closed-budget land accounting approach, we establish a mid-20th century global carbon stocks account. Our approach integrates global forest assessments from the mid-20th century, previously ignored in global land change studies, and inventory-based land use reconstructions across the 20th century with contemporaneous information on potential carbon stocks, the likely presence/absence of woody cover and the extent of shifting cultivation in the tropics. In a scenario-based analysis, we find that vegetation stored 540 PgC in biomass (median of 1728 cases per world region; inner quantiles 455-618 PgC). We focus on two Focal Cases, with total carbon stocks of 454-469 PgC, representing reasonable assumptions of carbon densities in forests and other wooded lands to reveal the distribution of carbon stocks across 8 land categories and 14 world regions. We found that ecosystems in Southern America, Western Africa and the erstwhile Soviet Union stored more than 27, 16 and 12% of all carbon stocks, predominantly in forests. Carbon stocks in Other Vegetated Lands, calculated as a residual from all known land uses, demonstrated the highest uncertainties. Comparisons with early-21st century carbon stocks estimates revealed significant reductions in global carbon stocks, but with distinct subcontinental characteristics, providing first evidence of a carbon stocks transition following a forest area transition underway in industrialised regions in the Global North as well as indicating the maximum possible carbon sequestration from restoration initiatives in a realistic timeframe in the future. Our integrative methodology can be used to reconstruct global carbon stocks over the 20th century to supplement other carbon flux-based modelling efforts, thus helping to constrain present and future simulations of global biomass carbon stocks.
Variation characteristics of runoff and sediment in the middle reaches of the Yellow River based on Copula function
Authors: Liu Huanyong , Yang* Qi
Published: March 2022

Abstract:In order to grasp the temporal and spatial variation of runoff and sediment transport and the relationship between runoff and sediment in the Yellow River, the Mann-Kendall test was used to analyze the trend of runoff and sediment load based on the data of runoff and sediment load from 1950 to 2020 at Tongguan station. This paper adopted a method based on moving correlation coefficient to diagnose the variation of watershed runoff and sediment, which was verified with cumulative curve method and regression analysis method. The Pearson III distribution was selected to fit the runoff and sediment distribution before and after the variation, and the combined runoff and sediment distribution was established based on Copula function. The variation characteristics of runoff and sediment at Tongguan station were compared and analyzed to study the wetness-dryness encountering of runoff and sediment at different times. Results show that: (1) The annual runoff at Tongguan station underwent a stepwise decrease until about 1990, and the amount of sediment load continued to decrease after 1983. (2) Taking 1985 as the segmentation point, the mean value of runoff and sediment decreased from 1986 to 2020 compared with that from 1956 to 1985. When the design frequency P≤90%, the runoff and sediment load decreased, while when P>90%, the runoff decreased and sediment load increased. (3) In both time periods, the synchronous frequency of runoff and sediment load wetness-dryness was greater than the asynchronous frequency of wetness-dryness, and the probability of wetness-dryness combination was the smallest, and the frequency of each combination was more uniform after the variation period. The implementation of soil and water conservation measures and the control of water and sediment by large-scale water conservancy projects were the main reasons that led to the change of the wetness-dryness of water and sediment. This work was supported by the National Key Research and Development Program [grant number 2016YFC0500802].

Keywords: runoff; sediment load; Copula function; the Yellow River Basin