bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Phase Coupled THMC Modeling of Gas Extraction from Hydrate Reservoirs
Authors: wani Sahil , Samala Rahul , Kandasami Ramesh Kannan , Chaudhri Abhijit
Published: February 2023

The unconventional source of energy such as the methane gas hydrate sediments are typically found in substantial quantities in permafrost regions and in deep-sea continental shelves. Extracting gas from these hydrate sediments might result in problems associated with seafloor subsidence, well-bore collapse, and submarine landslides. During gas extraction, there are various physical processes that are commonly observed such as thermal changes, dissociation of hydrates, the flow of fluids, and the deformation of the geomaterial. Thus, to understand all these processes, an appropriate multi-physics numerical model needs to be developed which can quantify the gas production due to the dissociation of hydrates coupled with solid deformation. Further, in order to take into account the effect of hydrate saturation on mechanical strength and stiffness, an advanced elastic-plastic constitutive (HISS-MH) model for gas hydrate sediments was used. In this study, a thermo-hydro-mechanical-chemical model was developed using the finite volume method (for mass balance and energy equations) and the finite element method (for geomechanics equations). After the numerical implementation and validation, the effect of various well-bore positions along the reservoir's depth on the settlement and cumulative gas production was investigated. A well-bore at the top, middle, and bottom of the reservoir are the three distinct scenarios that are independently examined. The bottom well-bore has the lowest overall settlement, while the middle well-bore has the highest after one year of gas production. A well-bore in the middle of the reservoir is preferable due to its greater overall gas production and least differential settlement. 
An advanced towed CTD chain for high resolution physical-biological in situ measurements in the upper ocean
Authors: Kock Thomas , Calil Paulo , Wobbe Florian , Seidel Gerd , Riethmüller Rolf , Deschner Stephan , Heineke Martina , Baschek Burkard
Published: February 2023

Eddies, fronts, and filaments of varying scales populate the upper ocean and are particularly important in coastal regions. These features play a vital role on biogeochemical and mixing processes as well as in the energy budget. To capture their high spatial variability, it is desirable to simultaneously resolve the horizontal and vertical gradients of hydrographic properties on scales from O(10) m to O(100) km. We present an improved towed CTD chain for rapid quasi-synoptic in situ measurements of submesoscale oceanographic features to fill this observational gap. The advanced towed CTD chain is robust, lighter and scientifically more useful than previous versions. Added flexibility in terms of freely adaptable chain and sensor setup enables tailor-made surveys for a variety of research questions. The advanced towed CTD chain collects data at a very high horizontal resolution in O(1) m with a vertical resolution between 1 to 10 m, depending on CTD probe count and spacing. Individual CTD probes used within the chain are self-contained instruments equipped with temperature, conductivity, pressure and either fast response dissolved oxygen or fluorescence sensors placed at multiple depths enabling simultaneous hydrographic and biogeochemical studies at high resolution. With the flexible probe hardware it is possible to collect data either with real-time data visualisation for adaptive sampling missions or - in a much simpler and lighter setup - log data internally for offline evaluation. Together with the towed CTD chain a set of software tools and techniques for processing CTD chain data has been developed to provide an easy-to-use and complete system. Data examples collected in various areas like the Amazonas river plume and Cape Verde Island wake highlight the advanced CTD chains robustness, flexibility and scientific capabilities.
Towards quick clay monitoring in the city of Oslo, Norway with urban seismic noise
Authors: Bruland Charlotte , Köhler Andreas , Oye Volker
Published: February 2023

Historically, there is one larger quick clay landslide in Norway every year. Since 80 percent of those happen in known quick clay risk areas, it is important to monitor these sites continuously. Alna, a busy, urban area in Oslo, is an example of such a location where a quick clay slide could lead to substantial human and economical losses.In this study we use ambient noise methods to monitor changes in the subsurface at Alna using a small array of three-component seismic sensors. To retrieve small velocity changes, we apply coda wave interferometry using 12 months of urban seismic noise (above 1 Hz).We compare the observed day-to-day changes to air temperature, precipitation, and water levels in a nearby river, and observe environmental velocity fluctuations well correlated with air temperature and precipitation. In particular, freezing and thawing produces strong changes in seismic velocity (up to 4 percent). The surface wave-coda used here is sensitive to changes in shear wave velocity, which in turn can be used to detect changes of the sub-surface properties. Therefore, observed velocity variations at Alna could have potential for monitoring and early warning of quick clay instabilities.
Soil desilication affects the nutrient and silicon status of cassava in South Kivu, DRC.
Authors: Barhebwa Balangaliza Fidèle , Vanlauwe Bernard , Li Zimin , Delvaux Bruno
Published: February 2023

Cassava (Manihot esculenta) is widely cropped in many tropical countries. It can be planted and harvested throughout the year making it a major crop for food production and safety. Surplus production can generate income, helping to improve livelihoods. Yet, in DRC, the cassava value chain is poorly developed and its production faces many threats as it lacks support services at almost all levels, although R&D organizations are involved at farm level in production, training, soil improvement and disease control. Though nutrient supply increases productivity, cassava is said to thrive on poor soils. Soil infertility is therefore a major constraint in most cassava growing areas.Here we highlight the relationship between soil weathering stage and nutrient status of cassava plants in three agroecological zones in South Kivu, DRC. Zones (Z) 1 and 2 encompass ferrallitic soils derived from, respectively, old basalt and gneiss in highlands around Bukavu. Zone 3 includes a variety of soils derived from lacustrine deposits in the Uvira plain. The soils key out as Ferralsol (Z1), Acrisol (Z2), Cambisol and Fluvisol (Z3). Through a survey of 720 households, we identified farms with similar management and selected 120 plots (40/zone) for topsoil-foliar sampling.In Z1 and Z2, the soils are poor in silt as their texture ranges from sandy clay to fine clay. The soils in Z3 are lighter: loamy sand to sandy clay loam. Our data confirm that the Z1-2 soils have reached an advanced degree of weathering, with weathering indices (TRB, Si/(Al+Fe), CIA, BDI, Parker Index) typical for the ferrallitic domain. In contrast, the soils in Z3 are moderately weathered with mineral reserves 10 times higher. Desilication is strong in Z1-2, but particularly in Z1 where gibbsite occurs with kaolinite. In contrast, Z3 soils contain weatherable minerals (mica, feldspar, plagioclase). The contents of leaf Ca, Mg and K are higher in Z3 than in Z1-2 while Ca depletion correlates with a relative excess of K, suggesting a Ca-K antagonism in cassava. Strong desilication occurs in Z1 soils where bioavailable silicon is extremely low. Yet, we could extract plant phytoliths in all sites, with varying coatings of aluminum, which thus seems to be taken up by cassava. 
Rapid and massive 335 million m3 glacier bed erosion after detachment of the Sedongpu Glacier (Tibet)
Authors: Kääb Andreas , Girod Luc
Published: February 2023

Following the 130 106 m3 detachment of the Sedongpu Glacier (south-eastern Tibet) in 2018, the Sedongpu valley underwent drastic and rapid large-volume landscape changes. Between 2018 and 2022, and in particular during summer 2021, an enormous volume of in total ~335 106 m3 was eroded from the former glacier bed, forming a new canyon of up to 300 m depth, 1 km width and almost 4 km length. The mass was transported into the Yarlung Tsangpo (Brahmaputra) River and further. Several rock-ice avalanches of in total ~150 106 m3 added to the total rock, sediment and ice volume of over 0.6 km3 that were exported from the basin since around 2017. The recent events at Sedongpu Glacier represent a rapid and irreversible process of landscape transformation from a sediment-filled glacier valley to a glacier-free one with a deeply incised canyon, impressively confirming that glaciers are able to protect their soft beds against massive erosion. Once uncovered, the erosion potential of soft glacier beds is here demonstrated to be possibly enormous for some glaciers in terms of volumes and rates. Such erosion could be particularly extreme for fine-grained subglacial sediments and for elevated glacier beds where large amounts of subglacial sediments are stored. The 2018–2022 landscape development at Sedongpu represents an extreme example of rapid paraglacial slope response highlighting extreme glacier erosion potentials and related hazards from debris flows and impacts on rivers. Such consequences of climate change in glacierized mountains have so far not been considered at this magnitude.
Seismic hazard assessment of the Lebanese Restraining Bend: A neo-deterministic approach
Authors: Nemer Tony , Vaccari Franco , Meghraoui Mustapha
Published: February 2023

The Lebanese Restraining Bend is an active bend along the Dead Sea Transform Fault in the eastern Mediterranean region where several destructive earthquakes happened throughout history. In this paper, we assess the gross features of seismic hazard of the Lebanese Restraining Bend by applying a neo-deterministic method that involves the generation of synthetic seismograms distributed on a regular grid over the study area. We use the regional seismicity, seismic source zones, focal mechanism solutions, and velocity structural models. We present maps of ground displacement, velocity, and acceleration. This is the first study that generates neo-deterministic seismic hazard maps for the Lebanese Restraining Bend using representative ground motion modelling. Our results show that displacement values of 15-30 cm and velocity values of 30-60 cm/s can be expected along most of Lebanon. In addition, 0.15-0.30 g acceleration values can dominate most of the Lebanese territory and surrounding areas. It is evident from these results that the study area in general and Lebanon in particular constitute a high seismic hazard area, which necessitates further attention from the authorities regarding the precaution measures needed to mitigate the effects of potential catastrophic seismic events; in addition, more detailed investigations are needed at local scale for specific sites of interest.
Geomorphological and sedimentary features of an underwater lava tube: the Túnel de la Atlántida (Lanzarote, Spain)
Authors: Lario Javier , Martín-Pozas Tamara , Sanchez-Moral Sergio , Cañaveras Juan Carlos , Fernandez-Cortes Angel , Cano Roberto , Lopez-Tercero Cecilio , Roldan Alvaro , Martin Esther , Perez-Mejias Carlos , Cheng Hai
Published: February 2023

The Túnel de la Atlántida (Atlantida Tunnel), located in Lanzarote Island (Canary Islands, Spain), with a length of about 2000 m and a depth of 64 m, is the largest submerged lava tunnel in the world. It corresponds to the submerged part of the lava tube complex of the La Corona volcano, with a length of about 10 km. During the development of the Sublantida Project, using diving techniques, various forms associated with the formation of the volcanic tube have been catalogued and a study of its sediments, minerals and speleothems has been carried out, including XRD, ESEM and petrological microscopy. It has been possible to propose a paleoenvironmental reconstruction from the formation of the volcanic tube, ca.21 Ka ago, to the present. The geomorphological, petrological, and sedimentary characteristics associated with the formation of the lava tube justify its importance as a World Geological Site of Interest.Acknowledgments: This project has received funding from the Spanish Ministry of Science and Innovation and the Spanish State Research Agency (grants CGL2017-91218-EXP and PID2019-110603RB-I00-SUBSYST). It is a contribution to the IGCP Project 725.
The representation of summer monsoon precipitation over northeast India: Assessing the performance of CORDEX-CORE model experiments
Authors: Ahamed Mohammad Rafijuddin Ali , Sharma Akanksha , Wani John Mohd , Dimri Ashok Priyadarshan
Published: February 2023

In this study, the performance of the output data from the latest high-resolution Coordinated Regional Climate Downscaling Experiment-Coordinated Output for Regional Evaluations (CORDEX-CORE) model simulations is assessed with respect to the corresponding gridded Indian Meteorological Department (IMD) and ERA5 observations in representing the monsoonal precipitation over northeast India (NEI) for the period 1979-2005. Here, in this study, three different RCM model simulations (COSMO, RegCM4.7 and REMO) downscaled over the South Asian CORDEX domain are used. To understand how these RCMs perform over a data scarce region like NEI, various statistical techniques were used to evaluate their performance. Our results show that the COSMO model experiments perform better (moderate bias) with respect to both the observations as compared to other two RCMs. In contrast, the RegCM model experiments show very wet bias, whereas the REMO model experiments show more dry bias across a significant part of the study area. Quantitatively, the COSMO suite of models exhibits a little overestimation (~7 to 13%) in comparison to IMD, while an underestimation (~14 to 18%) is seen with ERA5. However, with respect to both the observations, the monsoon precipitation is overestimated (~15 to 80%) by the RegCM model and is underestimated (~15 to 50%) by the REMO model experiments. Overall, the output data from the CORDEX-CORE model experiments reproduces the monsoon precipitation over the study region but with biases that vary spatially over the study region. Finally, the results from this study offer a thorough assessment of the output data from the CORDEX-CORE model experiments over the largely unexplored NEI and hence can be considered a good tool to study climatological processes over the data-scare regions.
Emissions pathways compatible with 1.5ºC and 2ºC stabilized warming in fully-coupled Earth System Models: first results from AERA-MIP
Authors: Silvy Yona , Terhaar Jens , Burger Friedrich , Joos Fortunat , Allen Myles , Brovkin Victor , Buzan Jonathan , Georgievski Goran , Lacroix Fabrice , Lee Donghyun , Frölicher Thomas
Published: February 2023

Climate policies such as the Paris Agreement are framed in terms of global warming levels. Based on past warming and past CO2 emissions, the amount of future cumulative CO2 emissions allowed to keep global warming at or below a global warming level can be estimated. Yet, global warming scenarios in the successive Coupled Model Intercomparison Projects are framed in terms of prescribed atmospheric CO2 concentration or emissions, yielding a wide range of warming levels per CO2 pathway in response to the different transient climate responses to cumulative emissions in the coupled climate models. Based on these scenarios and the latest model projections, the IPCC Sixth Assessment Report assessed climatic impacts of different warming levels. These impacts are thus evaluated in simulations where the warming targets are passed transiently, at different points in time, and not stabilized, as opposed to how climate agreements are framed.Here, we propose a new Model Intercomparison Project AERA-MIP building on an adaptive approach - the Adaptive Emissions Reduction Approach - that successively calculates the compatible emissions to stabilize global warming at the required temperature target. Earth System Models (ESMs) are run forward in emission-driven mode, with prescribed, model-specific emissions successively calculated every five years, so that all models reach the same warming target and thereafter stabilize at this warming level. The warming uncertainty is thus side-stepped, while different emissions pathways emerge out of the variety of participating ESMs. The approach is based on the TCRE framework and successively adapting for any changes in the Earth System that might affect global mean surface temperature, including the zero emissions commitment as emissions approach zero.Simulations of the first participating modelling centers already reveal a panel of emissions pathways that successfully stabilize global warming at 1.5ºC and 2ºC. This includes the decline rate from peak emissions, the timing of having to reach net-zero emissions, and the magnitude of negative emissions needed to stabilize the climate. These different emissions pathways result in a range of atmospheric CO2 concentration evolution (350 to 450 ppm at year 2100 in the 1.5°C stabilization scenario) and distribution of anthropogenic carbon in the Earth System components. Unlike concentration-driven projections, these AERA simulations provide an uncertainty range for impacts that are directly affected by atmospheric CO2 concentration such as ocean acidification. The project also includes temporary temperature overshoot simulations using the AERA approach.
Representation of Arctic mixed-phase clouds in ECMWF forecasts during ACLOUD
Authors: Müller Hanno , Röttenbacher Johannes , Schäfer Michael , Ehrlich André , Wendisch Manfred
Published: February 2023

The representation of Arctic clouds in numerical weather prediction models is challenging, especially for mixed-phase clouds with both a liquid and ice phase present. We compare measurements conducted during the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign, which took place in May/June 2017 northwest of Svalbard, Norway, with the operational ‘Atmospheric Model high resolution’ configuration (HRES) of the Integrated Forecasting System (IFS), operated by the European Centre for Medium-Range Weather Forecasts (ECMWF). Instead of using cloud retrieval products from airborne remote sensing, the comparison is performed in the observational space of spectral solar irradiances reflected by the clouds. To allow such an analysis along the flight track at flight level, the operational ecRad radiation scheme of the IFS is used in offline mode. Besides the HRES model output, vertical profiles of concentrations of trace and greenhouse gases provided by the ECMWF Atmospheric Composition Reanalysis 4 serve as the input for ecRad. The ability of the IFS to realistically represent the airborne radiation measurements collected during ACLOUD is evaluated for flight sections above sea ice and open ocean. Inconsistencies between the upward irradiance observed during ACLOUD and the simulations by ecRad are found and may originate from uncertainties introduced by the cloud fraction, the cloud phase, the sea ice albedo, and the ice optics parameterization. Our analysis aims to separate the influence of the different macro- and microphysical parameters on the upward irradiance. To disentangle the impact of these parameters, the spectral irradiance is analyzed where e.g. the impact of liquid and ice phase can be separated. Different case studies give insight into a sub-grid cloud cover variability that is not seen by the IFS above open ocean and an overestimation of the measurements by ecRad above sea ice that can be explained by the lack of cloud brightness. EcRad is additionally run with improved ice optics parameterizations. The choice of the applied ice optics becomes more important with an increasing ice water path of the clouds and is investigated in detail within the near-infrared bands of ecRad.
Systematic reorientation of diamagnetic fabrics of Taunus quartzite due to experimental impact cratering
Authors: Tiwari Sonal , Agarwal Amar , Kenkmann Thomas , Poelchau Michael H.
Published: February 2023

Systematic reorientation of diamagnetic fabrics of Taunus quartzite due to experimental impact cratering Sonal Tiwari1, Amar Agarwal1, Thomas Kenkmann2, Michael H. Poelchau21Department of Earth Sciences, Indian Institute of Technology-Kanpur, Kanpur – 208016, India.2Geology, University of Freiburg, 79104 Freiburg, GermanyCorresponding author´s email: sonaljp20@iitk.ac.inAbstractPara- and ferromagnetic fabrics are known to provide essential clues for understanding impact cratering processes. However, research on the effects of shock waves on diamagnetic fabrics is lacking. We, therefore, conducted a hypervelocity impact experiment on a block of diamagnetic Taunus quartzite and studied the changes in diamagnetic fabrics. Taunus quartzite was formed by a low-grade Variscan metamorphism that overprinted a 405 Ma old sandstone. It consists of c. 91 vol % quartz and a fine-grained, greenish phyllosilicate-bearing matrix (c. 8 vol %), along with small amounts of rutile, chromite, zircon, monazite, and iron oxides.The experiment was carried out on a 20 cm Taunus quartzite cube with a two-stage light-gas gun of the Fraunhofer Ernst-Mach Institute for High-Speed Dynamics (EMI) in Freiburg (EMI), Germany. The gun has a 8.5 mm calibre launch tube. The 0.3690 g basalt sphere projectile was accelerated to 5.457 kms-1, with a target chamber pressure of 1.2 mbar. The projectile diameter (dp) was 6.18 mm. Later, 14 mm-diameter nonmagnetic diamond bits were used to drill oriented cylindrical cores from unshocked and shocked Taunus quartzite blocks.  The AMS of the unshocked and shocked specimens was determined at room temperature in KLY-4S Kappabridge (AGICO). Following the AMS measurements, the cylindrical specimens were cut to make thin sections, which were studied under a Leica DM4 scanning optical microscope.Hypidiomorphic grain texture, serrated grain boundary, grain boundary migration, ataxial veins, Boehm lamellae, and recrystallized quartz represent the natural microscopic features. Impact-induced microstructures include trans- and intragranular microfractures. Our AMS results demonstrate that in the crater subsurface, the reorientation of the diamagnetic fabrics is concentrated in a zone of ~4 projectile diameters (25 mm) width directly below the point of impact. Higher reorientation in this zone indicates the concentration of damage. The damage is concentrated directly below the point of impact. Another important observation is that weak shock waves have caused an increase in the bulk susceptibility. These results, thus, show that the changes in diamagnetic fabrics can be used as a proxy for plastic deformation caused by shock waves at low peak pressures.Figure. The images show the specimens' position (black dots), the point source (brown dot), the impact crater (brown arc), and the variation in the orientation of k3.
Rocks with rotating blocks: 1D displacement, rotation and wave propagation
Authors: Zhang Maoqian , Pasternak Elena , Dyskin Arcady
Published: February 2023

Fragmentation of rocks, e.g. splitting into blocks, is a common occurrence at a range of scales from rock fragmentation caused by rockbursts or blasting to blocky rock mass produced by systems of fractures to rubble-pile asteroids. Common in these diverse objects is the ability of blocks (fragments) to assume relatively independent displacement and/or rotation. Modelling deformation of blocky/fragmented rocks is complicated by the phenomenon of elbowing [1] whereby the rotating block pushes away the neighbouring blocks. The direction of the push can be independent of the direction of block rotation making the problem strongly non-linear (the “absolute value” type non-linearity). In order to investigate elbowing we constructed a simple 1D physical model of a chain of blocks with one translational and one rotational degrees of freedom. It is found that when one block (the initial block) is rotated, the neighbouring blocks may not rotate, only displace, depending on the magnitude of friction and the number of blocks in the chain. A discrete element (3DEC) model of the chain is developed. It shows the conditions of rotation of the blocks and the rotational wave propagation following a pulse rotation of the initial block. Pasternak, E., Dyskin, A.V., Estrin, Y. (2006) Deformations in transform Faults with rotating crustal blocks. Pure Appl. Geophys. 163 2011–2030.
 Acknowledgement. The authors are grateful to Dr I. Shufrin and School of Engineering workshop for help with designing and manufacturing of the physical model. EP and AVD acknowledge support from the Australian Research Council through project DP210102224.
Evolution of lightning activity observed during rapid intensity changes of tropical cyclones
Authors: Rosická Kateřina , Kolmašová Ivana , Santolík Ondřej
Published: February 2023

We study evolution of lightning activity accompanying rapid intensity changes of tropical cyclones worldwide. We use a dataset of 400 tropical cyclones occurring between 2012 and 2017. We use the cyclones tracks from the International Best Track Archive for Clime Stewardship. The lightning data are provided by the World Wide Lightning Location Network (WWLLN). We inspect the lightning activity and median stroke energies accompanying rapid intensifications (RI) of cyclones, defined as increases of the wind speed by more than 30 kt in 24 hours, and their rapid weakenings (RW), defined as decreases of the wind speed by more than 40 kt in 24 hours.In an area of radial wind maximum (RWM), we observe a stroke density of 15.1 strokes/(100 km)2/hour for RI and 21.8 strokes/(100 km)2/hour for RW, respectively, which is much higher than average RWM density 7.9 strokes/(100 km)2/hour over the duration of the cyclone. A median stroke energy is 0.3 kJ during RI and 0.7 kJ during RW. It means that during rapid intensification of cyclones, there are less strokes with slightly higher energies and during rapid weakening there are more strokes with slightly lower energies. When analyzing the cyclones in both hemispheres separately, we obtain 0.3 kJ for RI and 0.6 kJ for RW in the northern hemisphere, and 0.8 kJ for RI and 0.9 kJ for RW in the southern hemisphere. The difference in the stroke density during RI and RW was observed larger in the northern hemisphere (19.7 vs 34.1 strokes/(100 km)2/hour), when in the southern hemisphere the stroke density is much lower and differs less (4.4 strokes/(100 km)2/hour for RI and 5.1 strokes/(100 km)2/hour for RW). 
Historical habitat mapping based on black-and-white aerial photography
Authors: Huber Nica , Price Bronwyn , Ginzler Christian , Holderegger Rolf , Bürgi Matthias
Published: February 2023

Information regarding the spatial arrangement and extent of habitats in the past is highly important for understanding present biodiversity patterns, assessing restoration potential and fighting extinction-debt effects. Due to increasing intensity of land use, European landscapes have changed profoundly over recent decades, with the trend accelerating following World War 2. Here, we explore the feasibility of deriving a 1946 habitat map for Switzerland compatible and hence comparable with the present-day area-wide habitat map. We take advantage of the newly available orthorectified composite of aerial photographs taken in summer 1946 by the US-Army and provided by swisstopo. The ortho imagery (1 m resolution) is segmented into image objects based on spectral and shape homogeneity for 7 case study areas (320 -508 km2), which represent the main biogeographical regions of Switzerland. Initial training data is derived by manual aerial orthoimage interpretation differentiating 16 habitat classes including wetland, grassland, arable land, hedges, orchard meadows and open forest. A random forest model is trained to classify the segments using variables describing spectral information, image texture, segment shape, topography and climate. To increase the accuracy of the classification, an iterative and semi-automated active learning technique is applied. This technique complements the initial training data with new data for segments with high classification uncertainty. With this contribution, we demonstrate the potential and challenges of object-based image analysis, machine learning and active learning to derive habitat maps from historical black-and-white aerial photography.
Accumulation rates of salt-marsh blue carbon at Lindisfarne, northern England, and their relationship with sea-level change
Authors: Gore Catrina , Gehrels Roland , Smeaton Craig , Andrews Luke , McMahon Lucy , Hibbert Fiona , Garrett Ed
Published: February 2023

Salt marshes sequester carbon at rates significantly exceeding those found in terrestrial environments. This ability arises from the in-situ production of plant biomass and the effective trapping and storage of both autochthonous and allochthonous organic carbon. The importance of this blue carbon store for mitigating increasing atmospheric carbon dioxide depends on both the rate at which carbon is buried within sediments and the rapidity with which that carbon is remineralised. It has been hypothesized that carbon burial rates, in turn, depend on the local rate of sea-level rise, with faster sea-level rise providing more accommodation space for carbon storage. This study addresses these three key aspects in a salt-marsh sediment study from Lindisfarne, northern England. We quantify rates of carbon accumulation by combining a Bayesian age-depth model based on 210Pb and 137Cs activities with centimetre-resolution organic carbon density measurements. A Bayesian isotope mixing model pinpoints terrestrial sources as providing the majority of stored carbon. We compare two approaches for assessing the relative proportions of labile and recalcitrant carbon based on a two-pool modelling approach and thermogravimetric analysis. Preliminary results indicate that during the 20th century more carbon was stored at Lindisfarne salt marsh during decades with relatively high rates of sea-level rise.
Cirrus cloud formation by gravity waves
Authors: Dolaptchiev Stamen , Spichtinger Peter , Baumgartner Manuel , Achatz Ulrich
Published: February 2023

Vertical ascent due to gravity waves (GW) represents one important formation mechanism for cirrus clouds, i.e., clouds consisting solelyof ice crystals. Further, GWs can substantially influence the microphysical cloud properties and cloud life cycle, which are crucialfor the radiative impact of the cirrus clouds. Here we investigate the interactions between high-, mid- or low-frequency GWs and cirrusclouds in the tropopause region. Utilizing asymptotic analysis reduced equations are derived for the self-consistent description of thecirrus dynamics forced by a monochromatic GW. This allows for the construction of prototype parameterization of the number nucleated icecrystals. The GW-cirrus interactions are studied further in cloud resolving large eddy simulation and the results are used to evaluatethe asymptotic parameterization.
Modelling climate-substrate interactions in microbial SOC decomposition
Authors: Pallandt Marleen , Ahrens Bernhard , Schrumpf Marion , Lange Holger , Zaehle Sönke , Reichstein Markus
Published: February 2023

Soil organic carbon (SOC) is the largest terrestrial carbon pool, but it is still uncertain how it will respond to climate change. Especially the fate of SOC due to concurrent changes in soil temperature and moisture is uncertain. It is generally accepted that microbially driven SOC decomposition will increase with warming, provided that sufficient soil moisture, and hence enough C substrate, is available for microbial decomposition. We use a mechanistic, microbially explicit SOC decomposition model, the Jena Soil Model (JSM), and focus on the depolymerization of litter and microbial residues by microbes. These model processes are sensitive to temperature and soil moisture content and follow reverse Michaelis-Menten kinetics. Microbial decomposition rate V of the substrate [S] is limited by the microbial biomass [B]: V = Vmax * [S] *  [B]/(kMB + [B]). The maximum reaction velocity, Vmax, is temperature sensitive and follows an Arrhenius function. Also, a positive correlation between temperature and kMB-values of different enzymes has been empirically shown, with Q10 values ranging from 0.71-2.80 (Allison et al., 2018). Q10 kMB-values for microbial depolymerization of microbial residues would be low compared to those of a (lignified) litter pool. An increase in kMB leads to a lower reaction velocity (V) and V becomes less temperature sensitive at low substrate concentrations. In this work we focus on the following questions: “how do temperature and soil moisture changes affect modelled heterotrophic respiration through the Michaelis-Menten term? Is there a temperature compensation effect on modelled decomposition rate because of the counteracting temperature sensitivities of Vmax and kMB?” We model these interactions under a mean warming experiment (+3.5 °K) as well as three soil moisture experiments: constant soil moisture, a drought, and a wetting scenario.
Unprecedented rainfall intensification over Western India during the 2019 summer monsoon
Authors: K. Mukherjee Sumit , Dey Choudhury Ayantika , Raghavan Krishnan , Vellore Ramesh , Guhathakurata Pulak
Published: February 2023

Large areas of Western India (WI) recorded the highest seasonal (June–September) monsoon precipitation during 2019 since 1901, resulting in disastrous floods claiming hundreds of human lives. Our analysis illustrates that widespread heavy rainfall in this region markedly came from three intense rain episodes (IREs), viz. 1) 28 June to 12 July, 2) 24 July to 11 August, and 3) 1–14 September, in the backdrop of strong positive Indian Ocean Dipole (pIOD) conditions evolving at the equatorial Indian Ocean. Based on the station count of heavy rainfall over WI, the IREs were defined in such a way that they captured the essence of both spatial and temporal coherences of heavy rainfall during those periods. The IREs favorably stemmed from northward propagating bands of organized convection embedded with stratiform precipitating systems. Analysis of satellite swaths brings out the prevalence of stratiform precipitation and elevated latent heating in the precipitating systems. Regression analyses of various atmospheric fields were performed to understand the dominant spatial structures during the IRE days. The continual top-heavy stratiform latent heating, in synergy with the pIOD-generated equatorial heating anomalies, forced a Rossby-wave pattern of high mid-tropospheric potential vorticity with the maximum over WI and an associated massive cyclonic vortex stretching across South and Southeast Asia (SSEA). It is found that the pIOD-induced enhanced cross-equatorial moisture transport fostered large-scale moisture convergence and deep convective ascent over much of SSEA, thereby leading to extensive heavy rainfall. This study highlights the ramifications of intense pIOD manifestations and their potential consequences for increasing the occurrence of hydrological extremes in WI as well as SSEA in the 21st century.
Modeling present-day and future extreme events in the Lake Victoria Basin
Authors: van Lipzig Nicole , Van de Walle Jonas , Demuzere Matthias , Fink Andreas H. , Ludwig Patrick , Nikulin Grigory , Pinto Joaquim , Prein Andreas F. , Rowell Dave , Wu Minchao , Thiery Wim
Published: February 2023

The population in the Lake Victoria Basin (LVB) is affected by extreme weather both on land, where flooding regularly occurs and on the lake, where nightly storms often catch fishermen by surprise. The CORDEX Flagship Pilot Study ELVIC investigates how extreme weather events will evolve in this region of the world and to provide improved information for the climate impact community. Here we evaluate the performance of five regional climate models at convection-permitting resolution and present projections for the future using COSMO-CLM in a pseudo global warming approach. Most substantial systematic improvements were found in metrics related to deep convection in convection-permitting models compared to their coarser scale counterparts. For the future, extreme precipitation and wind gusts are expected to increase over the lake due to an thermodynamically induced increase in water vapor whereas the impacts of weaker meso-scale circulation over the lake and stronger thunderstorm dynamics compensate each other. More compound events are expected for the future during which both rainfall and wind gusts are intense. Interestingly, the mean precipitation is strongly affected by uncertainties in large-scale dynamics whereas thermodynamics dominate extreme precipitation. This might imply that uncertainties in future projected extremes are smaller than those in mean precipitation.
Increase in daytime ozone exposure due to nighttime accumulation in a typical city in eastern China during 2014–2020 
Authors: Wang Junhua , Ge Baozhu , Wang Zifa , Wang Dawei , Lin Weili , Ji Dongsheng , Pan Xiaole , Li Jie
Published: February 2023

Tropospheric ozone (O3) pollution, as one of the major environmental problems, poses a significant threat to

human health and ecosystems. In the past, the study of O3 risk has only focused on the daytime, neglecting to

analyze the role of nighttime concentrations, which may have led to underestimation of O3 exposure hazards. In

this study, we investigated the long-term variation of O3 during April to September from 2014 to 2020 in Rizhao,

an industrial city on the east coast of China. We also calculated its exposure effects on human health and

vegetation with variety of metrics especially both daytime and nighttime indexes. The results showed that

various indexes of O3 in Rizhao were on the rise during 2014–2020, and the growth rate of O3 at nighttime was

greater than that during the daytime. This increase in concentration at nighttime have weakened the benefits of

the reduction in O3 formation from the precursor emissions control, which contributed more than 94% to the risk

of O3 exposure to human health. Short-term field observations showed that O3 in Rizhao is still sensitive to

volatile organic compounds (VOCs). This suggests that emission reduction measures for Rizhao should consider

the emissions ratio of NOx and VOCs instead of NOx only, as well as take into account the emissions of precursors

at nighttime to reduce the nighttime O3 level. Such an approach has the potential to reduce O3 pollution and its

harm to human health and vegetation effectively.
Prognostic Ozone For ICON: Enabling UV Forecasts
Authors: Hanft Valentin , Ruhnke Roland , Seifert Axel , Braesicke Peter
Published: February 2023

Stratospheric ozone (O3) absorbs biologically harmful solar ultraviolet radiation, mainly in the UV_B and UV_C spectral range. When reaching the surface, such UV radiation poses a well documented hazard to human health. In order to quantify this amount of UV radiation and to make it generally understandable, the World Health Organization has defined an UV Index[1]. It is calculated by weighting the incoming solar irradiance at surface level between 250 and 400 nanometers with their ”harmfulness” to the skin and scaling the results to values that normally range between 1 and 10, surpassing 10 for excessive UV exposure.Implementing UV Index forecasts in numerical weather prediction (NWP) models allows to alert the public in time if special care for sun protection needsto be taken. The German Weather Service (DWD) uses its NWP model ICON (ICOsahedral Nonhydrostatic Model)[2] to offer such a forecast for Germany[3]using external data such as ozone forecasts by the Royal Dutch Weather Service (KNMI) and radiation lookup tables[4].In our project we extend the capability of ICON to provide a configuration of self-consistent UV Index forecasts that do not require external data. For this, we use ICON-ART[5],[6] with a linearized ozone scheme (LINOZ)[7] and couple the prognostic ozone to the atmospheric radiation scheme Solar-J[8].Here we present the current state of our UV Index forecast system and compare our results to available reference data.References:[1] World Health Organization, World Meteorological Organization, United Nations Environment Programme, and International Commission on Non-Ionizing Radiation Protection. Global solar uv index : a practical guide,2002.[2] Günther Zängl et al.. The icon (icosahedral non-hydrostatic) modelling framework of dwd and mpi-m:Description of the non-hydrostatic dynamical core. Quarterly Journal of the Royal Meteorological Society, 2015.[3] https://kunden.dwd.de/uvi/index.jsp.[4] Henning Staiger and Peter Koepke. Uv index forecasting on a global scale. Meteorologische Zeitschrift, 2005.[5] D. Rieger et al.. Icon–art 1.0 – a new online-coupled model system from the global to regional scale. Geoscientific Model Development, 2015.[6] J. Schröter et al.. Icon-art 2.1: a flexible tracer framework and its application for composition studies in numerical weather forecasting and climate simulations. Geoscientific Model Development, 2018.[7] C. A. McLinden et al. Stratospheric ozone in 3-d models: A simple chemistry and the cross-tropopause flux. Journal of Geophysical Research: Atmospheres, 2000[8] J. Hsu, M. J. Prather et al.. A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-j v7.5. Geoscientific Model Development, 2017.
A New Lumped Descriptor of Basin-Wide Hydrological Connectivity
Authors: Dell'Aira Francesco , Meier Claudio I.
Published: February 2023

In their efforts to study the rainfall-runoff conversion process, hydrologists have deployed a variety of approaches. Despite the huge range of methodologies, a general theme can be identified: there is a trade-off between how generalizable a model can be across different basins and the degree of detail in basin characterization. On one hand, regionalization approaches and deep-learning models use lumped information, typically covering some combination of average geometric, topographic, land-cover, and climatic characteristics of a basin. Based on these descriptors, some general, typically empirical relationship is derived to explain the hydrological response of any watershed within a homogeneous region, e.g., by fitting a regional equation to predict the 10-yr flood at ungauged locations, or by developing regional statistical models on the pooled, standardized data from all the hydrologically similar basins. On the other hand, distributed, physically-based models attempt to simulate the water exchanges occurring within a catchment at different spatial and time scales, at the cost of a detailed, spatially-explicit basin characterization, with the resulting lack of transferability to other watersheds.While a lumped characterization of basins is crucial for a variety of approaches aimed at model transferability, such as regionalization techniques for flood prediction or deep learning models for flood forecasting, most procedures only consider basin-averaged properties or at most their distribution. Thus, they are unable to account for hydrological connectivity, even though it is well known that it has strong effects on a watershed’s response. For example, the percentage of impervious area is often used as a proxy for the level of urbanization in catchments, but it cannot provide any information about how urbanized areas are located with respect to each other and the watershed outlet, although different spatial configurations of these may result in different hydrological behaviors, for the same precipitation input.We propose a new, lumped hydrological connectivity index that can incorporate information on how different parts of a basin, with their various topographic and land-use characteristics, are connected to each other and the stream network. In this way, we incorporate their relative contributions to the hydrologic response of the watershed, depending on their location. This index can be regarded as a condensed measure of the potential that each location has for generating runoff at the watershed outlet, given spatially-explicit characterizations of its properties. It can be used in synergy with other lumped descriptors to provide a more detailed basin characterization that reflects hydrological connectivity.We test the predictive power of the proposed index in the framework of regional flood frequency analysis finding that it benefits well-established approaches for hydrological prediction in ungauged basins.
Data from depth to surface to define the 3D anatomy of an active fault-propagation fold: a key example from the western Caucasus (Georgia)
Authors: Bonali Fabio Luca , Tibaldi Alessandro , Russo Elena , Alania Victor , Chabukiani Aleksandre , Enukidze Onise , Tsereteli Nino
Published: February 2023

In the present work we showcase a multidisciplinary study aimed at defining the ongoing deformation processes due to fault propagation and folding at the Tsaishi fold, western Caucasus (Georgia).Our approach consists in the integration of geomorphological observations, field geological-structural data and seismic reflection sections, allowing us to reconstruct a 3D model of this active fold, from depth to surface.The Tsaishi fold is an anticline located at the southwestern tip of the Rioni Basin uplifted area, at the foothill of the Greater Caucasus. The folding process that has been recognized started at the beginning of the Middle Miocene, although preliminary data suggest the possibility of an initial local uplift in the Oligocene. Considering field observations, we suggest that the folding process continues nowadays, giving rise to a south-verging anticline, as shown by upwarped late Quaternary river deposits.Integrating seismic reflection sections and field observations, we show that the fold backlimb is affected by three main back-thrusts, whereas, based on seismic sections, at the foot of the forelimb a main north-dipping thrust is very close to the surface. Where the thrust reaches the surface, we recognized the presence of a 13-km-long fault scarp (or fold scarp), where historical seismological data locate the epicenter of the strongest earthquake of the area, with Ms 6.0, the so-called Tsaishi earthquake of 1614 CE.