bluuebunny/crossref_metadata_2025 huggingface dataset:
Responses of phytoplankton community to silicate-based and calcium-based ocean alkalinity enhancement
Authors: Xin Xiaoke , Kittu Leila Richards , Ortiz Cortes Joaquin , Groen Anna Wiebke , Riebesell Ulf
Published: March 2024

Ocean alkalinity enhancement (OAE) has been proposed as a strategy to sequester carbon dioxide (CO2) from the atmosphere by adding alkaline substances to seawater. In addition to alkalinity, various dissolution products could be released under OAE, depending on the choice of alkali mineral used. These products such as silicate and changes in carbonate chemistry can impact the competitive fitness of phytoplankton species, which could directly or indirectly affect the compositions of the phytoplankton community. Currently, there are knowledge gaps pertaining to the potential ecological impacts of alkalinisation on natural phytoplankton communities, which hamper a comprehensive evaluation of OAE for its large-scale implementation.To address these gaps, we carried out an in situ mesocosm experiment examining the response of a natural plankton community over 53 days in the temperate mesotrophic waters of the Raunefjord south of Bergen, Norway to two alkali mineral applications. We simulated two mineral types, a calcium-based (quicklime) and silicate-based (olivine) alkalinisation in a non-equilibrated approach. NaOH was used in both mineral treatments to establish a gradient of six alkalinity levels ranging from ambient (~2400 µmol kg-1) to ~3000 µmol kg-1 in steps of 150 µmol kg-1. Silicate-based and calcium-based alkalinisation were simulated through the addition of MgCl2 and CaCl2, respectively. Additionally, the treatment simulating olivine-based OAE received 70 µmol L-1 of Si(OH)4. Since phytoplankton was nutrient limited from the onset of the experiment, nutrients (nitrate, phosphate) were added halfway through the study to allow for an explicit detection of responses.Here we report on the responses of the phytoplankton community to the simulated OAE scenarios. Our results indicate that phytoplankton abundances remained largely unaffected across the alkalinity gradient and between mineral types during the oligotrophic phase of the experiment. However, significant differences in the phytoplankton community response were observed post nutrient addition. Here, coccolithophores exhibited a negative response to increasing alkalinity in the silicate-based treatment, whereas the correlation was relatively weak in the calcium-based treatment. We attribute these responses, in part, to changes in carbonate chemistry such as low pCO2, which may limit coccolithophore growth and the out-competition by diatoms favoured by added silicate.Overall, our findings suggest minimal risks associated with OAE under oligotrophic conditions over a 20-day period. However, the potential for species-specific negative impacts of increasing alkalinity should be carefully considered under high nutrient availability. These results represent a crucial first step towards understanding the ecological responses of phytoplankton communities, helping to define the safe operating space in non-equilibrated OAE implementations. 
Role of Anthropogenic Forcing and Decadal Oscillations on the Delayed Withdrawal of Indian Summer Monsoon
Authors: Sundaresan Aneesh , Bódai Tamás , Sijikumar Sivarajan , Satpathy Susmit Subhransu
Published: March 2024

            The mean Indian summer monsoon (ISM) rainfall as well as the duration of monsoon spell have a profound impact on the agriculture practice in the country. Due to the recent increase in surface temperature, global circulation patterns exhibit considerable changes which also affects the characteristics of ISM. The present study aims to find out any long-term changes in the monsoon onset and withdrawal dates over different parts of India and the possible mechanisms behind it. During the last four decades, the trend analysis of ISM onset dates over south India and north-west (NW) India shows an early onset in both regions. However, the trends are statistically less significant. In the case of the monsoon withdrawal dates, trends over NW India and south India show a statistically significant delay of about 6 days/decade and 3.25 days/decade, respectively. As a result, the monsoon season over NW India and south India shows a lengthening of about 7.8 days/decade and 3.5 days/decade, respectively. During the withdrawal phase of the ISM, a stronger monsoon low-level jet and an enhancement of the ISM rainfall have been observed in recent decades. The enhancement in rainfall activity and the strengthening of the low-level jet in the withdrawal phase reaffirms the delayed withdrawal of the ISM in recent decades.            The role played by factors such as Indian Ocean warming, Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO) on the ISM withdrawal is examined. The AMO has changed its phase from negative to positive in recent decades, particularly after about 1998, which might have played a key role in enhancing the meridional tropospheric temperature gradient. The stronger meridional tropospheric temperature gradient and the Eurasian surface warming observed in recent decades might played a key role in the delayed monsoon withdrawal over NW India. The CESM2 large ensemble data analysis shows that both the external forcing as well as the decadal phase shift of the AMO and PDO, favour the delayed withdrawal, while the latter plays a dominant role.
Snow-model parameter identifiability across space and time.
Authors: Blandini Giulia , Avanzi Francesco , Gabellani Simone , Campo Lorenzo , Ercolani Giulia , Cremonese Edoardo , Galvagno Marta , Morra di Cella Umberto , Yamaguchi Satoru , Hirashima HIroyuki , Ferraris Luca
Published: March 2024

Accurate modeling of Snow Water Equivalent (SWE) and snow depth significantly improves hydrologic forecasts, particularly in mountains area, thus supporting a more sustainable resource management. In balancing the need for detailed process representation with computational efficiency, snow models often rely on ill-defined, or very site specific parameters that hamper upscaling and transferability. Here, we focus on the identifiability and stability of such parameters by comparing a traditional temperature-index modeling approach with a hybrid temperature- and radiation-index method. Analyses were performed across 7 locations around the world. A hybrid temperature -radiation modeling approach reduces calibration variability while improving the simulation accuracy of snow water resources. Although requiring additional parameters, this method ensures higher parameter transferability and stability, making it more suitable for operational applications. The insights derived from this study offer a significant step ahead towards advancing operational snow hydrology modeling.
Ice-nucleating particles over the Labrador Sea during the M-Phase campaigns
Authors: Tarn Mark D. , Foster Polly B. , Clarke Sam J. , McQuaid James B. , Robinson Joseph , Raif Erin N. , Barr Sarah L. , Bastin Katherine H. , Thompson Kathleen A. , Shi Zongbo , Cotton Richard , Field Paul R. , Bower Keith N. , Gallagher Martin W. , Choularton Thomas , Murray Benjamin J.
Published: March 2024

As the Earth warms, it is important to understand how a change in the ice:water ratio in mixed-phase clouds influences the cloud-phase feedback; a cooling effect caused by the change in albedo of the cloud. Ice-nucleating particles (INPs), aerosols that can trigger the freezing of liquid cloud droplets via heterogeneous nucleation, may regulate this cooling process by maintaining the ice contents in clouds, hence it is necessary to identify the types, sources, and concentrations of INPs to determine their contribution and better represent this in models. We undertook ship and aircraft-based INP measurement campaign in the Labrador Sea region, which features clouds that are susceptible to the effect of INPs, in 2022: (i) a cruise on the RRS Discovery, as part of a joint SEANA/M-Phase project in May-June, and (ii) a flight campaign on the FAAM BAe-146 aircraft as part of the M-Phase project in October-November that focused on northwesterly cold air outbreak (CAO) cloud systems.During the SEANA/M-Phase ship cruise, real-time measurements of INP concentrations were taken using a Portable Ice Nucleation Experiment (PINE) expansion chamber alongside offline filter-based measurements and bulk seawater measurements. Preliminary results suggest that high INP concentrations correlated with air masses that had passed over the exposed (i.e. not snow- or ice-covered) coastline of Greenland, while lower concentrations correlated with air masses that had passed over the sea ice. These results suggest a high-latitude source of INPs not currently accounted for in models, the study of which could be crucial in understanding their influence on clouds in a changing climate.Offline filter-based INP measurements during the FAAM aircraft campaign showed highly reproducible INP concentrations during CAO events (0.05 INP L−1 at −15 °C), with both much higher and much lower concentrations during non-CAO days. Further analysis will include further processing of the campaign data, including aerosol size distributions together with real-time INP data taken from a new online continuous flow diffusion chamber (CFDC), the Met Office Ice Nuclei Counter (INC), aboard the aircraft, together with aerosol composition analysis via scanning electron microscopy of filters, which will allow the types and sources of INPs in the Labrador Sea region to be established.The M-Phase campaigns in the Labrador Sea have shed some light on INP properties in the region, and further processing of the data will allow determination of INP sources, activity, and relationship with aerosol size distributions. Better representation of INPs in models based on these findings will allow for reduced uncertainty in the cloud-phase feedback and its impact on climate predictions.
Trend and Variability in the Long-Term Relationship Between Eurasian Snow Cover and Indian Summer Monsoon Rainfall
Authors: Pandey Dr Pushpa , Kunz Dr Michael , Dwivedi Dr Suneet , Goswami Dr Bhupendra Nath
Published: March 2024

The predictability of Indian Summer Monsoon Rainfall at any given time period depends on the strength of its relationship with predictable drivers like the El Nino–Southern Oscillation (ENSO) that are known to undergo significant epochal variations. While the relationship between Eurasian snow cover fraction and Indian Summer Monsoon Rainfall has also shown a similar epochal variability in recent decades, its stationarity on centennial or longer timescales remains unknown. In the present work two indices of snow cover fraction have been unraveled, on the basis of the observed relationship between the dominant modes of Indian Summer Monsoon Rainfall variability and snow cover fraction over a period of 115 years (1901–2015), that encapsulate its spatio-temporal variability. It has been observed that the relationship between the snow cover fraction indices and Indian Summer Monsoon rainfall have a statistically significant increasing trend with a weak multidecadal variability superimposed on it, making significant positive correlation between the two highly probable in the coming decades. With snow cover fraction driving the North Atlantic Oscillation (NAO) that subsequently drives the Indian Summer Monsoon Rainfall variability, it has been demonstrated that the NAO plays a pivotal role in modulating the teleconnection between the Indian Summer Monsoon Rainfall and snow cover fraction on a multidecadal time scale.Keywords: El Nino–Southern Oscillation, North Atlantic Oscillation
Quantum-based Accelerometers for Satellite Gravimetry Missions
Authors: Fletling Nina , Knabe Annike , Müller Jürgen , Weigelt Matthias , Schilling Manuel
Published: March 2024

Accelerometers are an essential component of satellite gravimetry missions, as the non-gravitational forces acting on the satellites must be known in order to determine the Earth's gravity field. However, the accelerometers currently in use are one of the limiting factors regarding the accuracy of the determined gravity field, which opens up room for improvement. Among other techniques, quantum-based accelerometers are promising candidates to be applied in the future.In order to achieve the required technology readiness level for operation in space, a pathfinder mission is planned to demonstrate the technology. This mission is being prepared in the framework of the Cold Atom Rubidium Interferometer in Orbit for Quantum Accelerometer - Pathfinder Mission Preparation (CARIOQA-PMP) project funded by the European Union. In addition to designing the pathfinder mission and instrument to achieve a specific performance, simulations are carried out based on the expectable performance not only for the pathfinder mission but also beyond on the utilisation of quantum-based accelerometers in future satellite gravimetry missions. This includes a broad study on different mission types, such as a single satellite with high-low satellite-to-satellite tracking, as foreseen in the pathfinder mission, or a satellite constellation with GRACE-FO-like conditions utilising low-low satellite-to-satellite tracking. Here, closed-loop simulations are used to investigate under which conditions the determined gravity field solution benefits from a quantum-based accelerometer compared to a classical electrostatic one and which challenges still need to be addressed in order to improve resolution and accuracy.
A new global crust model: ECM24
Authors: Lu Biao , van der Meijde Mark , Fadel Islam , Reguzzoni Mirko , Rossi Lorenzo , Sampietro Daniele , Cammarano Fabio , Julia Jordi
Published: March 2024

Despite 160 years of probing the world crust, due to lack of seismic and ground gravity observations, there are still white spots in the worlds' crustal thickness map. The crustal structure in those regions is among the least understood of the Earth's continental areas, and variations in basic but fundamental parameters - such as crustal thickness - are still poorly constrained over large areas. Recent research has shown that satellite gravity-based crustal modeling in regions with limited seismological coverage can provide unique insights in crustal thickness and underlying geodynamical processes.In almost all of these cases the gravity signal related to crustal structure is isolated by applying 3 different corrections: topography, sediments, and upper mantle structure. Of these three, the upper mantle correction is least well addressed. It doesn’t account for any lateral inhomogeneity upper mantle composition close to the crust-mantle boundary. As a result, satellite gravity data reductions for upper mantle structure are a source of uncertainty. Our new model includes a new state-of-the-art upper mantle correction. By combining satellite gravity and seismic tomography, we have formulated a new methodology to integrate potential field data inversions, tomographic modelling, and petrolophysics into a single inversion scheme. Our crustal thickness model ECM24 has therefore more accurate crustal thickness values, is seismically fitting better than previous models, and is also very consistent with gravity observations.
Morphological Changes in Jupiter’s Northern Circumpolar Cyclones as Revealed by JunoCam and JIRAM. 
Authors: Brueshaber Shawn , Orton Glenn , Hansen Candice , Levin Steven , Mura Alessandro , Grassi Davide , Fletcher Leigh N. , Rogers John , Eichstadt Gerald , Wong Michael H. , Bolton Scott
Published: March 2024

Juno has observed the circumpolar cyclones (CPCs) on Jupiter with the visible-light camera, JunoCam, and the 2-5 µm infrared JIRAM camera, since orbit insertion.  The CPCs have distinctive cloud features, and unique characteristics that broadly classify into two morphological forms, chaotic and filled.  As revealed by JunoCam, the filled CPCs typically appear with large bright cloud features on the periphery, similar in appearance to a circular saw blade.  Just inward of those, nearly uniform darker regions appear---probably stratiform clouds---occasionally displaying small hole-like openings, which appear bright at 5 μm. The overall appearance of the periphery and just inward is reminiscent of shear-like instability in the flow. Anticyclonic circulation has been witnessed in the center of several filled CPCs. Lightning has also been observed by JunoCam in one of the blade-like cloud features at perijove 31, and we occasionally observe thin, bright curvilinear cloud features and clusters of bright clouds with shadows indicating vertical structure. The chaotic CPCs, including the central cyclone, have a different morphology, however, appearing as a flocculent and tightly wrapped series of alternatively bright and dark spirals. Interestingly, CPC #2 has partially transformed from a chaotic morphology into a filled morphology, similar perhaps to how oval cyclones and barges in the low latitudes can sometimes transform into folded-filamentary cyclones (e.g., Clyde’s Spot).Here, we discuss each CPC and the central cyclone throughout the course of the mission thus far. We primarily use images captured by JunoCam and JIRAM, but we note that the MWR is now resolving the CPCs (see separate abstract), providing additional clues on their vertical structure. This work is an attempt to document the morphology of the CPCs and their changes for future modeling attempts to replicate them in detail, which, in turn, may provide additional insight into their formation, evolution, and stability.
Air clathrate hydrates of the Antarctic EPICA Dronning Maud Land ice core
Authors: Painer Florian , Weikusat Ilka , Drury Martyn , Kipfstuhl Sepp
Published: March 2024

Polar ice cores are a unique climate archive as they provide the most direct record of past atmospheric gas compositions. In the deeper part of polar ice sheets, most of the ancient air molecules are stored in the crystal lattice of clathrate hydrates (air hydrates). Continuous records of air hydrate number concentration, mean size and shape (geometric properties) exist for the Vostok and Dome Fuji ice cores in Antarctica and the GRIP ice core in Greenland. It was found that the geometric properties correlate with past climatic changes, but also evolve with depth due to physicochemical processes within the ice sheet.The EPICA Dronning Maud Land (EDML) ice core is located on an ice divide in the Atlantic sector of East Antarctica which allows for a comparison to Greenland ice cores. Furthermore, it differs from other Antarctic deep ice cores by a higher accumulation rate and higher annual mean temperatures on site. This makes it possible to analyze air hydrates with a higher temporal resolution (compared to the Dome Fuji and Vostok ice cores). These factors make the EDML ice core interesting for studying air hydrates.We use digital image analysis on ice thick section microphotographs to create a high-resolution record of air hydrate geometric properties below the bubble-hydrate transition zone. The image acquisition was done in the field, within a few days after the sample was drilled, in order to record information of the material before relaxation. Using traditional image analysis algorithms, we can confirm the correlation between climate and air hydrate geometrical properties. In addition, we examine the air hydrate spatial distribution and evolution via depth. Digital object segmentation and object analysis offer many advantages, such as fast and efficient analysis, improved statistical data, higher spatial resolution, over the traditionally used manual methods. We are excited to contribute to the future analysis of air hydrates in polar ice cores.
Glacial induced variations in the uplift – a challenge for the reference frame 
Authors: Kierulf Halfdan Pascal
Published: March 2024

Arctic areas are heavily affected by climate change. The temperature is increasing, the permafrost is melting, the sea ice is disappearing, and the glaciers are retreating. The elastic response of the changes in the glacier affects the earth crust. Locally on Greenland or Svalbard the uplift can reach several centimetres per year. The ice melting in Greenland is so large that it affects the land uplift in large parts of the Northern hemisphere.
The geodetic observatory in Ny-Ålesund is a key station in the global geodetic network. It is the northern most fundamental station, containing all the main geodetic techniques and important for the realisation of the ITRF. However, its stability has been questioned. The observatory experience variations in the uplift on seasonal, inter-annual, decadal and longer timescales. The uplift for a moving window of 5-years periods has increased from below 6 mm/yr in the 1990 to more than 12 mm/yr today. This has challenged the realisation and stability of global and regional reference frames. 
We have modelled the elastic response of glacier changes based on various glaciological sources. These results will be presented. We will in particular compare the elastic uplift with geodetic time-series from Ny-Ålesund and other GNSS in Svalbard and discuss how this could affect reference frames. Could for instance the VLBI scale issue in ITRF2020 be related to glacial changes? 
We found that the variations in the uplift can be explained by the glacier changes and close to 50% of the VLBI scale drift can be explained by glacier related accelerating uplift. 
QC-MAINS: A Quality Control-based Multi-Antenna GNSS/INS Tightly Integrated Model
Authors: chen guang'e , li bofeng
Published: March 2024

The integration of Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) has been widely used in civilian vehicular navigation, which can provide precise position and attitude for vehicle control and trajectory planning. Nevertheless, the accuracy of the GNSS/INS combined system inevitably diminishes when GNSS signals are frequently obstructed or interrupted, leading to an insufficient number of GNSS observations to mitigate INS drift. To improve the performance of the GNSS/INS system in such GNSS-compromised environments, nowadays the mainstream solution is further combining other sensors, i.e., Lidar, Camera or odometer. The crux of these approaches lies in introducing external pose information to supplement the missing GNSS signals. However, more sensors mean more complex system, as well as higher cost.In many so-called GNSS-compromised environments (i.e., routes under trees, urban canyons), GNSS signals do not completely vanish but are characterized by reduced quantity and weakened quality. This raises the question: Has the GNSS information under harsh environments been completely utilized? The answer obviously is no. To realize the fully utilization of the GNSS information, this work studied a Quality Control-based Multi-Antenna GNSS/INS Tightly Integrated Model (QC-MAINS). The tight integration of INS and the multiply antennas located at different positions on a vehicle can explore potential GNSS observations as much as possible. Furthermore, the low-quantity GNSS observations can be detected and isolated through cross-checks with multiple antennas. Experiment results show that the horizontal position root-mean-square errors (RMSEs) are reduced by about 42, 54, and 48% for three harsh routes, respectively.
A Bayesian inversion method for estimating ash emissions: accounting for meteorological uncertainty & quantifying uncertainty in the estimated emissions.
Authors: Webster Helen , Thomson David , Salter James
Published: March 2024

Atmospheric dispersion models are employed during volcanic eruptions to forecast the atmospheric transport and dispersion of the ash cloud. Uncertainties exist in the predicted ash cloud due to uncertainties in the ash emissions, in the atmospheric dispersion model and its parameterisations, and in the driving input meteorological data. A Bayesian inversion method has been developed for estimating the height- and time-varying profile of ash emissions using satellite retrievals of ash column load, atmospheric dispersion modelling and a prior estimate of emissions (Pelley et al., 2021). Gaussian distributions are assumed for the prior distribution of the emissions and for the errors in the satellite retrievals. An optimal emission estimate is obtained by finding the peak of the posterior probability density, subject to an imposed non-negative constraint on the emissions. The method is computationally efficient and suited for operational use.In the original design of the Bayesian inversion method, uncertainties in the atmospheric dispersion model and its input meteorological data are not considered. Errors in the input meteorological data can lead to discrepancies between the modelled and observed ash cloud locations and can affect the performance of the Bayesian inversion method. We employ ensemble NWP (Numerical Weather Prediction) data sets to overcome issues with meteorological errors. The Bayesian framework enables a model selection approach to be adopted, where a ‘best’ meteorological data set is chosen from within the ensemble. Using the eruption of the Icelandic volcano Grímsvötn in 2011 as a case study, we illustrate the impact meteorological errors can have on ash emission estimates and show how the ‘best’ meteorological data set leads to improvements in ash cloud forecasts.The posterior probability density is a multi-dimensional Gaussian distribution which contains information on the uncertainty in the estimated emissions. If time permits, I will describe recent attempts to obtain an ensemble of emission estimates by sampling from the posterior distribution. This is challenging because of the high dimensionality and the non-negative emissions constraint. Nonetheless, an ensemble of emission estimates from the posterior distribution would enable the uncertainty in the emissions estimate, and the associated uncertainty in the ash concentrations in the predicted ash cloud, to be quantified.
A European Perspective on Joint Probabilities of Multi-Hazards
Authors: Claassen Judith , Ward Philip , Jäger Wiebke , Koks Elco , de Ruiter Marleen
Published: March 2024

Natural hazards rarely occur in isolation. Frequently, one hazard triggers another, such as an earthquake triggering a tsunami. Likewise, the likelihood of a hazardous event can be amplified by the occurrence of a previous event, such as a drought amplifying the likelihood of a wildfire to occur. However, two extremes can also co-occur as a compound event, leading to even higher combined impacts.While the field of compound events is advancing rapidly, studies often focus solely on climatic extremes occurring at the same time, excluding non-climate-related hazards or previous triggering and amplifying conditions. Therefore, this research aims to better understand the dependencies between different (pre-conditioning) hazard magnitudes, geographic features, and historic natural hazard footprints accounting for both climatic and geological hazards.With the use of statistical tools, such as vine copulas, we model the relationships within two different hazard groups. The first group consists of drought, heatwave, and fuel indicators to calculate the risk of wildfires. The second group includes earthquakes, precipitation, and slope data to calculate the risk of landslides. While the first group is considered a compound event, the second group can be classified as a multi-hazard, with different triggering or amplifying relationships. For both groups, we attempt to use the same method to model stochastic events that include a potential hazard footprint for wildfires and landslides on a local to European scale. This model allows users to evaluate potential hazard combinations and footprints in their regions, enabling better preparedness for potential multi-hazard events.
Robustness of new models of the Matuyama-Brunhes field reversal
Authors: Ahmed Ahmed Nasser Mahgoub , Korte Monika , Panovska Sanja
Published: March 2024

Paleomagnetic data enables the global reconstruction of the Earth's magnetic field, allowing the investigation of significant global events like polarity reversal. When compared to prior polarity reversals, the most recent one, the Matuyama-Brunhes (MB), is the best recorded reversal event in terms of the amount of available paleomagnetic data. Nevertheless, the majority of these data have poor age control, and they are not distributed equally over the world. Few global spherical harmonic (SH) models have been presented so far for the MB; the most recent is the GGFMB model. These models investigated the evolution of the dipole and non-dipole field components during the reversal process, as well as the morphology of the magnetic field at core-mantle boundary and at the Earth's surface. However, the accuracy of the models features is limited by the aforementioned issues associated with the MB data. In this study, a set of eight SH models were generated for the MB from sub-sets of data, which were classified according to their geographic distribution, timescale reliability, temporal resolution, and type. Comparing the model outputs will allow us to assess how robustly the MB's models can resolve characteristics of the reversal.
Climate adaptation to change in high-flows: Comparison of high-resolution climate model projections
Authors: Chandrasekar Aparna , Boeing Friedrich , Marx Andreas , Rakovec Oldrich , Mueller Sebastian , Sharifi Ehsan , Leal Rojas Jeisson Javier , Samaniego Luis , Thober Stephan
Published: March 2024

Climate change is altering the water cycle from the global to the local scale. The increase in temperatures and changing precipitation patterns intensify not only mean values, but also the frequency and severity of extreme weather events, leading to alterations in water availability and distribution.This study assesses the impact of climate change on flood patterns (maximum annual river discharge) in Germany. Climate models ranging from different spatial scales will be compared for the five largest German catchments outlets (including headwaters). The climate model ensembles from the EURO-CORDEX initiative, and the ICON climate model from the Destination Earth Initiative / NextGEMS project will be used along with the mHM (mhm-ufz.org) model. The river discharge values produced from the mHM model will be used to calculate the Q90 (90th percentile of daily discharge) and the Qmax (maximum annual discharge) parameters.Initial results from the EURO-CORDEX initiative predict a 5-15% reduction in Q90 and Qmax in the summer half year, and a 5-30% increase in Q90 and Qmax in the winter half year, in the alpine regions in Germany. In the Elbe and Oder catchments (north-eastern part of Germany) there in a greater increase in Q90 and Qmax in the summer half year than the winter half year. This increase becomes more prominent with increasing warming. However, there is a large spread in the ensemble predictions, with uncertainty reducing with increasing warming. These parameters and results will be compared with the results from the ICON climate model to understand the contribution of spatial and/or temporal resoltion towards flood prediction.
Representing land-ocean heterogeneity via convective adjustment timescale
Authors: Polesello Andrea , Goswami Bidyut Bikash , Muller Caroline
Published: March 2024

Representing land-ocean heterogeneity via convectiveadjustment timescaleBidyut Goswami1 , Andrea Polesello1 , Caroline Muller1 .1Department of Earth Science, Institute of Science and Technology Austria, Klosterneuburg, AustriaJanuary 2024AbstractThe time needed by deep convection to bring the atmosphere back to equilibriumis called convective adjustment timescale or simply adjustment timescale, typicallydenoted by τ . In the Community Atmospheric Model version 6 (CAM6), convectionis parameterized through the Zhang-McFarlan scheme [1], where CAPE undergoesan exponential consumption, of which τ is the time constant. τ is a tunable pa-rameter in CAM6 and it has a default value of 1 hour, worldwide, on both oceanand land. Albeit, there is no justified reason why one adjustment timescale valueshould work over land and ocean both. Continental and oceanic convection is dif-ferent in terms of the vigor of updraft and hence can have different durations.[2, 3]So it is logical to investigate the prescription of two different convective adjustmenttimescales for land (τL ) and ocean (τL ). To understand the impact of representingland-ocean heterogeneity via τ , we investigated CAM climate simulations for twodifferent convective adjustment timescales for land and ocean in contrast to havingone value globally.Following a comparative analysis of 5-year-long climate simulations, we findτO =4hr and τL =1hr to yield the best results. In particular, we obtain a betterdescription of the Madden-Julian Oscillation (MJO). Although these τ values werechosen empirically and require further tuning, the conclusion of our finding remainsthe same, which is, to use two different τ values for land and ocean.References[1] G. Zhang and N. A. McFarlane, “Sensitivity of climate simulations to the parameterization ofcumulus convection in the canadian climate centre general circulation model,” Atmosphere-Ocean, vol. 33, no. 3, pp. 407–446, 1995.[2] C. Lucas, E. J. Zipser, and M. A. Lemone, “Vertical Velocity in Oceanic Convection offTropical Australia,” Journal of the Atmospheric Sciences, vol. 51, pp. 3183–3193, 11 1994.[3] R. Roca, T. Fiolleau, and D. Bouniol, “A Simple Model of the Life Cycle of MesoscaleConvective Systems Cloud Shield in the Tropics,” Journal of Climate, vol. 30, pp. 4283–4298, 6 2017.
High-Resolution Sea and Lake Level Reconstructions of the Late Cretaceous: Evidence for a 'Seesaw' Ocean-Land Water Circulation Model
Authors: Ji Kaixuan , Li Mingsong , Gong Fanhao , Zhang Haotian , Yuan Shuai , Zhang Dejun
Published: March 2024

The investigation into water circulation mechanisms within greenhouse environments, particularly their link to orbital forcing and consequent impacts on organism-environment coevolution, is garnering increased attention. A key uncertainty is the nature of variations in continental and oceanic water reservoirs on an ice-free Earth and the primary factors driving sea level changes. Traditional approaches like sequence stratigraphy and sedimentology have provided rough and limited insights, hindering a detailed and comprehensive understanding of water circulation in deep time. Therefore, high-resolution inversion of sea and lake level changes is vital for studying global hydrological cycle. Employing advanced sedimentary noise models (DYNOT and ρ1), based on astrochronology and time-series analysis, this research reconstructs detailed water-level variations in key regions: the continental Songliao Basin of Northeast China, the marine Basque-Cantabric Basin in Spain, and the marine Espírito Santo Basin in the western South Atlantic, covering the entire Maastrichtian Stage to the Cretaceous-Paleogene (K-Pg) boundary. These reconstructions, corroborated by sedimentary facies analysis and paleosol studies, reveal 1.2 Myr and 2.4 Myr periodic variations in sea and lake levels, exhibiting a 'seesaw' pattern of opposite trends. This indicates that sea level fluctuations might be influenced by changes in continental water reservoir content, providing new insights into the complex interplay between terrestrial and marine hydrological systems.
Monitoring of selected hydro-morphological elements on natural rivers in Slovakia depending on river scale
Authors: Boraros Tomas , Melova Katarina , Kostal Daniel
Published: March 2024

Sedimentary processes in aquatic environments are very important parts of monitoring and describing the hydrological regime. In our study, we are dealing partially with analyses of hydro-morphological processes in natural rivers. Natural river is described by almost complete absence of anthropogenic pressure, in this case, the results of our monitoring are used to evaluate the ecological status of the water bodies in accordance with Water framework directive. We identify changes in river channel from historical point of view (f.e. shortening), monitor bedforms (bars, islands, riffles etc.), sediment types (bedrock, boulders, sand, etc.), however, dealing with the quantification of the sediment regime is out of our scope. According to the river scale, we use partly different measurement techniques, and in case of different river types, some elements could be irrelevant for some of them. In this study, we explain the type specific elements for the selected river types.
Stress, energy, and the onset of failure around geometrically irregular faults: Example from the East Anatolian Fault
Authors: Sagy Amir , Morad Doron , Lyakhovsky Vladimir
Published: March 2024

Geometrical irregularities of faults drive stress heterogeneities that strongly affect the seismic rupture. Here we analyze the effect of fault topography and remote stresses during the interseismic phase on the static stress pattern around faults and on the onset of failure. The analytical solution is derived using perturbation theory for a defined interface topography. We apply our solution for the static stress field near the East Anatolian Fault and we show that a large stress barrier is developed around the segment that ruptured during the Mw 7.8 Kahramanmaraş Earthquake. Considering stress field conditions that are associated with left-lateral strike slip on the fault, we show how the barrier location is affected by the fault geometry, while the amplitude of stress variations are sensitive to the background stress values and their directions. The solution predicts that the value of the accumulated elastic energy in the host rock around the fault is maximal in the barrier region suggesting that in this area the elastic energy available for potential slip is the largest. We therefore suggest that the length of the ruptured segment and magnitude of the strong Kahramanmaraş Earthquake were greatly influenced by the stress heterogeneity generated by the fault geometry during the long interseismic period. This example of the East Anatolian Fault shows that the geometry of the fault is crucial for the location and the extent of earthquakes along it. We further suggest that the presented analytical approach provides a simple yet powerful new tool for assessing seismic hazards before earthquakes occur.
From drought to Storm Daniel: an overall assessment on the fragility of the Mediterranean region
Authors: Qiu Junliang , Zhao Wei , Brocca Luca , Tarolli Paolo
Published: March 2024

In 2022, Europe experienced an unprecedented drought. 2023 marked the warmest year globally on meteorological records, leading to droughts and wildfires in Greece during the summer. In July 2023, certain areas of the Mediterranean experienced sea surface temperatures 5.5°C higher than the annual average, contributing to severe summer heatwaves and wildfires in the Greek region. These conditions also provided ample thermal energy for the formation of Storm Daniel. From September 4th to 6th, Storm Daniel struck Greece, resulting in significant rainfall and flooding. Coordinated satellite monitoring revealed that the flooded area in central Greece reached 875.28 km². On September 10th, Storm Daniel hit Libya, leading to dam collapses and claiming the lives of over 11,000 people. Concurrently, the flood area in the northern deserts of Libya exceeded 1,000 km². From a global perspective, Europe has witnessed an increased frequency of extreme droughts and floods in recent years, while North Africa grapples with geopolitical instability. Climate change-induced natural disasters are further heightening the vulnerability of the Mediterranean region. Consequently, this study underscores the importance of (1) enhancing hydrological monitoring in arid and semi-arid regions of the Mediterranean, (2) developing a Mediterranean scale early warning system, and (3) stressing the imperative for the European Union and North African countries to collaboratively establish climate change adaptation strategies, aiming to avert humanitarian disasters triggered by climate crises.
Exudate dynamics and rhizosphere priming in wetland ecosystems
Authors: Krüger Namid , Mueller Peter
Published: March 2024

The release of organic substances from roots (exudates) to the soil system can induce changes in the mineralization rate of soil organic carbon (SOC) via so-called priming effects. Compared to other terrestrial ecosystems, mechanistic knowledge about priming effects in anoxic wetland soils is scarce, and few studies have investigated the composition and magnitude of root exudation in wetland plants. Given the disproportionate role of wetlands in the global soil carbon budget, this represents a critical knowledge gap in our understanding of terrestrial soil-climate feedbacks.Here we present data from (1) a meta-analysis to summarize all quantitative and qualitative observations on wetland root exudation; and (2) exudate-surrogate incubation experiments testing for exudate effects on wetland SOC decomposition under anoxic conditions.The meta-analysis shows that few comparable data on wetland exudation rates exist because extraction methods differ strongly, and only few species have been evaluated frequently. The data demonstrate that wetland plants not only release sugars, amino acids and organic acids into the rhizosphere, but also secondary compounds with a high allelochemical (e.g. gallic acid) or decomposition-hampering potential (e.g. phenolics). Their combined effect on the stability of soil carbon stocks is currently unpredictable on the ecosystem level. Our incubation experiments show that labile C inputs into an anoxic soil have a great potential to suppress SOC decomposition via negative priming. This finding contrasts to positive priming effects commonly found in oxic terrestrial soils and yields important implications for the stability of wetland SOC stocks in response to climate induced vegetation shifts.
Influence of the Kerguelen hotspot on eastern Indian lithosphere by trans-dimensional Bayesian inversion of Rayleigh wave dispersion data
Authors: Mullick Nirjhar , Kumar Vivek , Saha Gokul , Rai Shyam S. , Bodin Thomas
Published: March 2024

Mantle plumes play major role in modifying the continental lithosphere producing rifts and massive amounts of basaltic volcanism as the anomalously hot mantle undergoes decompressive melting. If conditions are favourable the rift may widen and a new ocean is formed. During the break up of Eastern Gondwana at ~ 130 Ma, the Kerguelen mantle plume influenced the separation of India from Antarctic and Australian plates and generation of the Eastern Indian Ocean. Eastern India-Bangladesh region (83-94ºE, 21-26ºN) carries imprints of the plume activity in the form of the Rajmahal and Sylhet traps and their subsurface expression in Bengal basin and extensive lamproytes. Existing geophysical studies of the region are mainly crustal scale and do not explicitly refer to the Kerguelen plume activity providing geophysical evidence for the same. We present here lithospheric shear velocity structure of the region up to a depth of ~ 175 km by trans-dimensional Baysian inversion of Rayleigh group velocity dispersion data (7-100s at 1º X 1º resolution). Using the same, we investigate the influence of the Kerguelen plume on the lithosphere of the Eastern India-Bangladesh region that comprises the Eastern India craton, the Bengal basin, the Bhrahmaputra basin, Bangladesh and the Shillong- Mikir plateau.
Resilience and adaptation of First Nations communities in Canada to disappearing winter road infrastructure in a changing climate
Authors: Salles Annette , Mullan Donal , Spagnolo Matteo , Catney Gemma
Published: March 2024

In Canada’s North, winter roads serve as vital lifelines for remote First Nations communities, connecting them to essential resources and services. Constructed over seasonally frozen lakes, rivers, and land, these temporary roads are the only means to transport food, fuel and building materials in large volumes. Winter temperature increases of > 3° C in several provinces have already led to shorter operating seasons and less lake ice thickness, compromising safety, supply, and well-being.Limited meteorological data, a lack of economic or political relevance and the provincial jurisdiction over winter roads have so far discouraged broader research. The few localised studies leave a large knowledge gap with respect to the historical correlation of climate data with winter road seasons and the ability to predict their future. In addition, scientific studies rarely include the existing traditional environmental knowledge without which the adaptive capacity and resilience potential of Indigenous communities cannot be fully understood and realised.Using GIS tools to create a map of all Canadian winter road systems, ERA5 data to analyse location-specific temperature trends, and observations of lake ice thickness to validate a one-dimensional lake model as proxy for freezing trends all aim to explore the natural science base. Surveys and extended interviews in a Manitoba First Nations community complement the study in a decolonising approach, following the concept of Two-Eyed Seeing.Comprehensive mapping shows that most winter road tracks have recently been rerouted to avoid lake surfaces despite the difficult terrestrial underground. Temperature trends are highest in January and vary from +0.4° C in Ontario to +1° C per decade in the Northwest Territories, while modelled ice thickness has decreased between 9% and 14% from 1950 until 2022. Shorter winter road seasons have resulted in food insecurity, educational deprivation, and a housing crisis in many remote First Nations communities, worsened by the intergenerational trauma of residential schools and legislative hurdles to self-determination as defined by the UN Declaration on the Rights of Indigenous Peoples.For Indigenous communities in Canada, cryosphere services are not limited to winter road infrastructure, they include traditional food harvesting, cultural connectivity and identity. Without a profound connection to the land, change observations remain inconsequential, adaptive measures and resilience unobtainable.