bluuebunny/crossref_metadata_2025 huggingface dataset:
Using HydroTiles to represent different hydrological regimes in a global Earth System model
Authors: Stacke Tobias , de Vrese Philipp , Gayler Veronika , Brovkin Victor
Published: March 2024

Land surface regions that are of crucial importance for climate dynamics, such as Arctic permafrost landscapes, are often extremely heterogeneous. In these areas, hydrological processes and heat fluxes, which are influenced by topographic features on the scale of a few meters, can affect processes such as permafrost thaw over large regions. Despite the emergence of Earth system models that can operate at a resolution down to one kilometer, hydrological heterogeneity at smaller scales is often overlooked. In addition, high-resolution models are computationally intensive, making them unsuitable for the time scales required to study the climate impacts of processes such as permafrost thaw.
In this study, we present an extension to the tiling infrastructure of the ICON Earth system model that enables the representation of different hydrological regimes within individual grid cells. This innovative approach facilitates the representation of lateral water flow connections between different areas within grid cells and the simultaneous representation of different surface water and soil moisture states, such as dry and wet conditions, within a single grid cell. The impact of this improvement is twofold. First, it provides a more accurate representation of surface and soil hydrology. Second, it is expected to improve the representation of land-atmosphere coupling, allowing us to better capture feedbacks across landscapes affected by strong hydrologic contrasts.
By enabling the representation of hydrological features in subgrids through tiles, which we call HydroTiles, we hypothesize that the HydroTiles setup could replicate some features of high-resolution simulations even at lower resolutions. This approach offers the potential to make simulations more computationally cost-efficient. In our presentation, we would like to highlight the advantages and disadvantages of the HydroTile setup compared to high-resolution simulations.
Source-to-Sink signal propagation in a coupled catchment-deep-sea fan system: the Sithas example from the Corinth Rift (Pleistocene, Greece)
Authors: Deiss Nolwenn , Rohais Sébastien , Regard Vincent
Published: March 2024

Since the early 2000s, the development of the Source-to-Sink (S2S) approach improved the understanding of variations in the sedimentary signal and its controlling factors within coupled catchment-sedimentary system. However, S2S study remains difficult, as the data and time scales of the distinct compartments of the system may be incompatible, poorly resolved or even lacking. The combined quantification of sediment budget in both the catchment’ and sedimentary basin’s parts of the system is a way to address this problematic.The aim of this study is (i) to jointly measure erosion and sediment deposition across an entire S2S system, and subsequently (ii) discuss the influencing factors and the mode of signal propagation. The study focuses on the system of Sithas (Corinth rift, Greece), where numerous geomorphologic markers (e.g., marine terraces) provide constrains to quantify eroded volumes, and a large offshore dataset is available to establish well-constrained sedimentary budget.To achieve this, we updated an age model for the last 800 ka. We then restored the volumes of sediment eroded in the catchment and quantified the volumes of sediment deposited offshore to estimate fluxes of sediments from the source and the sink during the last 800 ka Quaternary climatic cycles. We also compared these results with a multi-regression empirical model estimating suspended sediment loads (BQART).Erosion (source) and sediment (sink) fluxes have shown a gradual increase since 800 ka: from 3km3/Ma for the source and from 1. to 75. km3/Ma in the deep-sea fan (sink). This overall increasing trend is superimposed by cyclic variations, in both erosion and deposition signals. Significant increases in fluxes are observed over periods of around 12 ka every 120 ka (at circa 10, 120, 230 and 340 ka), which are followed by a progressive decrease. They coincide respectively with high sea levels according to the global eustatic curve (odd Marine Isotopic Stages). Surprisingly, the peaks of fluxes in deposition (sink) are preserved prior to the peaks of fluxes in erosion (source) with a time lag of around 30 ka. The comparison with BQART fluxes also shows the significant influence of the catchment size and the climatic factors such as temperature and precipitations in modulating the signal propagation.These observations suggest that even for small, coupled catchment-deep sea fan system, the signal propagation is not straightforward, and thus deserves much more attention in future works.
Metereological Drought in the western Po river basin: trends and characteristics from 1958 to 2023
Authors: Mombrini Emanuele , Tamea Stefania , Viglione Alberto , Revelli Roberto
Published: March 2024

Since the start of the 21st century, greater focus has been put on drought and its wide range of environmental and socioeconomic effects, particularly in the context of climate change. This is especially true for the North-western region of Italy, comprising the Piedmont and Aosta valley, which have been affected in recent years by droughts that have had acute effects on water resources and water security in all sectors, including agriculture, energy and domestic use. The region also belongs to the Mediterranean hot-spot, characterized by faster than global average warming rates and higher vulnerability to their effects. Therefore, characterizing the observed changes and trends in drought conditions is of particular significance. To this end, 60 years of precipitation and temperature data from the North West Italy Optimum Interpolation data set are used to calculate the drought indices SPI (Standardized Precipitation Index) and SPEI (Standardized Precipitation Evapotranspiration Index) at a shorter (3-month) and at a longer (12-month) time scale. First, trend analysis on precipitation and temperature is performed, finding limited areas with significant precipitation decrease and, conversely, a general temperature increase over the region, with higher values found in the higher elevation areas. Changes in meteorological drought are then evaluated, both in terms of drought indices trends and in terms of changes in the characteristics of drought periods, on both a local and regional scale. A relation between the altitude of the area and the observed changes is highlighted, with significant differences between the plain and mountainous portion of the region. The differences are mainly related to the observed trends, with the low-altitude part of the region displaying a tendency towards dryer conditions not in common with the mountainous area. Significantly, no trend is found at a region-wide level but is instead found when considering homogeneous areas defined by terrain ruggedness. Furthermore, changes in the number of drought episodes and in their severity, duration and intensity are found to be correlated with terrain ruggedness at all time scales.
Are there lightning Fires in the Amazon Rainforest?
Authors: Zhang Cunhui , Janssen Thomas , Jones Matt , Veraverbeke Sander
Published: March 2024

Tropical rainforests have exceptionally high biodiversity and store large amounts of carbon in biomass. However, large and frequent fires across tropical rainforests in the last decades threaten the ecosystem integrity of these ecosystems. The general belief is that fires in the Amazon rainforest are all human-ignited and that lightning fires do not occur in rainforests due to the predominant wet conditions. However, recent research indicates the possibility of lightning fires in tropical rainforests. Here, we aim to investigate the occurrence of lightning-ignited fires in the Amazon rainforest, a topic that has been largely overlooked in the current understanding of fire dynamics in this biome. We collected and analyzed data on lightning strikes, fire occurrences, and weather patterns derived from satellite imagery and climate datasets. The objective is to detect, quantify, and characterize lightning fires in the Brazilian Amazon rainforests, thereby providing new insights into the natural fire regime of this crucial ecosystem.
Surges in global N2O fluxes from saltmarshes are driven by increasing porewater nitrate and ammonium concentrations
Authors: Collier-Woods Devon , Ullah Sami , Comer-Warner Sophie
Published: March 2024

Saltmarshes have the potential to sequester large amounts of carbon, however, the value of stored carbon may be partially offset by emissions of the potent greenhouse gas nitrous oxide (N2O). Increased nutrients [NO3- and NH4+] have been shown to increase N2O emissions from saltmarshes, however, a global-scale analysis of this relationship has not been performed. Here, we present a global meta-analysis to investigate the relationship between N2O fluxes and porewater nitrogen and determine the relative importance of porewater NO3- and NH4+ as key drivers of enhanced saltmarsh N2O fluxes. Both porewater NO3- and NH4+ were significantly, positively correlated with N2O fluxes (p < 0.01), explaining 25 and 18% of the variation in fluxes, respectively. We estimate a global saltmarsh N2O flux of 0.012 Tg N2O yr-1, which is six times higher than the current estimate (0.0021 Tg N2O yr-1), representing an offset of 19% of the estimated global saltmarsh carbon burial. Using predicted future increases in riverine DIN export, our meta-analysis suggests that 17-31% of the estimated global saltmarsh carbon burial could be offset by a surge in N2O emissions under chronic mineral N pollution. This meta-analysis indicates the importance of reducing nutrient inputs into saltmarshes to reduce N2O fluxes and maximise their negative radiative forcing.
The MARE (MARine Energy) project Assessment of energy production potential from marine waves and currents: a case study from Aegadian archipelago
Authors: D'Alessandro Antonino , Sulli Attilio , Agate Mauro , Caruso Cinzia , Capizzi Patrizia , Cocchi Luca , D'Anna Roberto , Di Benedetto Andrea , Figlioli Anna , Gasparo Morticelli Maurizio , Mandiello Alfonso , Martorana Raffaele , Pisciotta Antonino , Speciale Stefano , Scirè Scappuzzo Sergio , Scudero Salvatore , Vitale Giovanni
Published: March 2024

The MARE (MARine Energy project), funded in the framework of PRIN PNRR, arises from the premise that the energy production from marine sources, becoming an important piece in the mosaic of renewable energies, the available resource must be well assessed, in order to demonstrate the real productive possibilities and attract investors. The activity presents the potential tools identified for the definition of a methodology capable of determining the potential of energy producibility from sea waves and marine current along the territorial waters of the Aegadian Archipelago. To assess the potential for the marine energy it is opportune to employ the most suitable methodologies for the analysis of such particularly complex system. The MARE project aims to contribute to the necessary knowledge so that the energy production from marine waves and currents may become a real resource for small islands.The MARE project focused on two main lines:The collection, organization and analysis of available environmental data, with particular reference to those strictly related to the studied problem;
The identification, on the basis of geological, geophysical and geochemical investigation of the potential for energy production of the highlighted case of study.
And includes the following types of surveys in the Aegadian Archipelago and surroundings:-           bathymetric surveys-           seismic microtremor investigations-           current meter surveys-           investigations of temperature and salinity parametersFor the following purposes:Assessment of Energy Production Potential from marine waves motion;
Assessment of Energy Production Potential from marine currents.
Investigating the intercorrelations of ecosystem services related to water resources at the catchment scale
Authors: Yu Zi-Rong , Yuan Jia-Ling , Chiang Li-chi , Wang Yung-Chieh
Published: March 2024

Ecosystems provide various direct and indirect benefits for human society, which are closely intertwined with human life, health, and economic well-being. However, pressures such as climate change, changes in land use/land cover, and human activities may pose threats or undermine the stability of ecosystems, consequently impacting the provision of ecosystem services. In recent years, climate change has altered precipitation patterns and increased the occurrence of extreme weather events, resulting in variations in watershed dynamics and affecting the stability of water resources. The impact on water resources has intensified, leading to changes in watershed ecosystem services and influencing the quality of human life and property security. This study is based on simulations using the Soil and Water Assessment Tool (SWAT) model in the Jhuoshuei River basin. Simulations cover historical periods (2002-2020) and near-future (2021-2040) and far-future (2081-2100) scenarios under RCP2.6 and RCP8.5 of CMIP5 models. Five indicators, which include freshwater provision index (FPI), green water scarcity (GWS), green water vulnerability (GWV), flood regulation index (FRI), and erosion regulation index (ERI), were selected for quantitative assessment and analysis of dry and wet season water provisioning and regulating services in the Jhuoshuei River basin. Spatial autocorrelation analysis was employed to identify high and low zones of ecosystem services, and Spearman correlation analysis was used to determine the trade-offs and synergies among the five ecosystem services indicators. The results indicate significant differences in the five indicators between dry and wet seasons. The FPI performs better in the wet season, while the other four indicators exhibit better performance in the dry season. Across historical and climate change scenarios, the relationships among the five indicators remain consistent. The FPI demonstrates a trade-off relationship with the other four ecosystem services, while the FRI, ERI, GWS, and GWV exhibit mutual synergies. This study shows the intercorrelations among the ecosystem services related to water resources, and the results serve as the references for water resources regulations and watershed management.Keywords: SWAT model, Provisioning services, Regulating services, Green water security, Jhuoshuei River basin
Advancing volcano surveillance through soil gas monitoring: insights from Stromboli Island, Italy.
Authors: Messina Mirko , Di Martino Roberto , Paonita Antonio
Published: March 2024

Soil gas monitoring proves to be a powerful tool for studying volcanoes and their subsurface dynamics. Various gas species are examined as indicators of volcanic activity, with a focus on understanding the processes governing gas emissions. Carbon dioxide (CO2) is of particular interest due to its significant release during both active volcanic periods and periods of dormancy. Hydrogen (H2) concentration is also analysed to gain insights into the oxygen fugacity of magmatic gases, a parameter that influences the redox state and the distribution of elements among solid, fused, and gas phases.To effectively monitor volcanic gases, automated geochemical stations are deployed to simultaneously measure multiple gas species. This study presents a comprehensive analysis of reducing capacity monitoring data collected at Stromboli during the 2021-2023 time window. This station records data on molecular hydrogen (H2) concentration, CO2 flux, CO2 concentration, soil water content, atmospheric pressure, temperature, and relative humidity.The dataset underwent normalization of variables and filtering processes of spurious data to facilitate Principal Component Analysis (PCA), allowing for the identification of linear dependencies among the variables. The results of the PCA reveal insights into the relationships of the monitored parameters, shedding light on potential factors influencing volcanic activity.These data reveal variations in reducing capacity and soil CO2 flux that correlate with changes in Stromboli's eruptive activity. The delay in CO2 variations following shifts in reducing capacity is attributed to the advective-diffusive transport of gases through the volcanic rock formations. This research contributes to a deeper understanding of the volcanic degassing of Stromboli and shows the efficacy of combining multiple regression analysis methods for filtering geochemical datasets. This research enhances our understanding of volcanic behaviour and aids in volcano monitoring efforts.
Why do acquisitive fine-roots exude more carbon: A cost-benefit model simulation
Authors: Sun Lijuan , Wu Tonghui , Yang Xinyao
Published: March 2024

Plants manipulate the activities of microbial decomposition in the rhizosphere, i.e. the so-called rhizosphere effects (REs). The more nutrient-acquisitive plants seem to allocate more carbon (C) to the rhizosphere to meet their nutrient demands. Alternatively, it is probably the fast-growing species are more C leaky. In this study, we induced plant regulation processes on C release and nutrient acquisition to the biogeochemical model of microbial decomposition. We simply increased two parameters, namely root exudation and plant competition capacity  against microbes for available nitrogen. Our model showed that C investment to the rhizosphere and plant nutrient-acquisition capacity with decomposers together determine the cost-benefit balance of rhizosphere effects. For each specific species with a specific nutrient-acquisition capacity, there is an optimal exudation invest for the plant’s best interests. Furthermore, co-existing species can have similar efficiency of C cost against N benefit by optimal pairs of exudation and competition capacity. Our model not only give mathematical explanation why acquisitive plants release more root exudation but also show promising tools to modeling rhizosphere effects at ecosystem levels.      
A Framework for Monitoring Above Ground Biomass of Hyper-Arid Rangelands in the Middle East
Authors: Johansen Kasper , Galvis Jorge Rodriguez , Cheng Hua , Almashharawi Samer , McCabe Matthew
Published: March 2024

In line with Saudi Vision 2030 and the ambitions of the Saudi Green Initiative to plant 10 billion trees and protect 30% of Saudi Arabia’s land and sea areas, large parts of Saudi Arabia are being transitioned into nature reserves and undergoing regreening activities, while also fencing off large areas for vegetation restoration and protection. To effectively manage the regreening and restoration initiatives, it is imperative to frequently monitor biomass changes over time and quantify the accumulation of biomass to determine if the restoration and tree-planting initiatives have the intended outcomes. However, landscape responses to regreening and vegetation restoration are poorly understood in hyper-arid rangelands. Environmental processes within different habitat zones might differ, which further complicates biomass monitoring. Here, we present a framework that is currently being applied across multiple hyper-arid rangelands in Saudi Arabia to estimate biomass within newly established nature reserves. The initial work focused on developing a scaling approach between ground, unmanned aerial vehicle (UAV), and satellite image data, including PlanetScope and Sentinel-2 imagery. Field sites were identified using Google Earth imagery and a number of criteria, including a 5-year Sentinel-2 NDVI time-series to identify greening events, terrain characteristics based on DEM data, and differences in vegetation functional types (annual and perennial grass/herbs/forbs, shrubs and trees), soil types, and habitats. Field-based measurements at selected sites focused on determining biomass of different vegetation functional types, using a double-sampling approach, including a limited number of destructive samples, and a large number of biomass estimates based on the structural and dimensional characteristics of the destructive samples. UAV-based light detection and ranging (LiDAR) and multispectral data were obtained for each site to estimate biomass from the field-based samples using different machine and deep learning approaches (random forest, support vector machines, vision transformer, UNet with attention encoder). It was found that LiDAR data provided useful information on vegetation height and volume, which improved the biomass estimates, whereas the multispectral data enabled discrimination between photosynthetic and non-photosynthetic vegetation components. Based on the UAV-derived estimates of biomass, a scaling approach was applied to estimate biomass from both PlanetScope and Sentinel-2 data, with results demonstrating that the higher spatial resolution of the PlanetScope data improved the accuracy due to the very sparse vegetation in most parts of the hyper-arid rangelands of this study. While hyper-arid rangelands are generally underrepresented in research studies worldwide, this research provide a viable framework for assessing vegetation dynamics of biomass both seasonally and annually.
The frequency of summer light rain projections in typical terrain over eastern China constrained by surface wind speed
Authors: Dong Xuechen , Gong Daoyi , Shi Cuicui
Published: March 2024

The variation of near surface wind speed is a key dynamic parameter in the orographic effect of precipitation over eastern China. In this study, we used the latest high-resolution outputs from six GCMs in CMIP6-HighResMIP to evaluate the performance of high-resolution models in simulating the orographic precipitation characteristics of typical mountainous areas in summer over eastern China. Combined with observational results, the orographic precipitation under warming scenarios was projected and constrained. The results indicated that during the contemporary climate reference period (1979-2009), although the relationship between model-simulated near surface wind speed and the orographic light rain frequency was consistently stable, the sensitivity of the orographic light rain frequency to surface wind variability was generally underestimated, with a deviation approximately 24.1% lower than the observational values. Comparison of model-simulated wind speed with observational records showed that the negative bias of the sensitivity value was mainly contributed by the overestimated wind speed in models. Based on observed near-surface wind speed to constrain and correct the orographic light rain frequency, the constrained estimates revealed a 36.1% reduction in orographic light rain frequency under a 1.5°C warming scenario, which is 8.6 times greater than the original predictions (4.2%). The MRI-AGCM3-2-S model, with a longer dataset, demonstrated a relatively stable reduction in orographic light rain frequency under different warming scenarios (1.5°C, 2°C, 3°C, and 4°C) after wind speed constraints, all of which are exceeding the original predictions.
Argentina Breaks Heat Records in the 2022/23 Warm Season: Influence of Synoptic Circulation, Local Feedbacks, and Climate Change
Authors: Collazo Soledad , Suli Solange , Zaninelli Pablo , García-Herrera Ricardo , Barriopedro David , Garrido-Pérez José M.
Published: March 2024

The summer of 2022/23 in Argentina marked an unprecedented period with 10 heat wave events (HWs), primarily affecting the central region. This study characterises the four most extensive HWs of that season through synoptic, thermodynamic, and attribution analyses.Regarding the synoptic conditions, we find that mid-level anticyclonic anomalies were essential for the occurrence of these HWs. Although they exhibited different characteristics, the high-pressure system was quasi-stationary in three of them, while it was transient in the other one. This atmospheric pattern interacted with the South Atlantic Convergence Zone and the South American Low-Level Jet, and played a fundamental role in the amplification of the HWs, providing a warming of ~+2°C (compared to what would be obtained by a random circulation).The terms of the thermodynamic equation reveal that diabatic processes were the main drivers of daily temperature changes in the analysed HW events. Horizontal advection also made an important (albeit secondary) contribution, particularly during a tropical air mass intrusion over central and northern Argentina.Local feedbacks were also important for understanding the events. North-central Argentina is a region of strong land-atmosphere coupling, and all HWs were preceded by soil moisture deficits impinged by three consecutive La Niña years. Using the flow-analogue technique, we quantify that the contribution of dry soils to warming was ~1°C (with respect to that of wet soils), suggesting that soil moisture deficits caused an increase in sensible heat fluxes and amplification of warming.Finally, we find that recent climate change has also exacerbated HW intensities by +0.5 to +1.2°C. Atmospheric circulation patterns similar to those observed during the events cause warmer conditions in the present than in the past, mostly due to temperature trends rather than changes in the intensity of weather systems.Our analysis reveals that the exceptionally high temperatures were a result of various factors, including the rare occurrence of a three-year La Niña-induced drought. Recent studies suggest that consecutive La Niña events may become more common due to climate change. Northeastern Argentina would be particularly affected by this shift due to its large response to ENSO and land-atmosphere interaction. Additionally, ongoing temperature trends are expected to accelerate, contributing to the intensification of HWs. Consequently, it is expected that similar extreme summers become more frequent in the 21st century.
Ecological trade-offs between leaf structure and plant nutrient demand to predict nutrient resorption in a terrestrial biosphere model
Authors: Sophia Gabriela , Caldararu Silvia , Stocker Benjamin , Zaehle Sönke
Published: March 2024

Nutrient resorption from senescing leaves is a critical process of plant nutrient cycling that can significantly affect plant nutrient status and growth, making it essential for land surface models in order to predict long-term primary productivity. Most models assume leaf resorption to be a fixed value of 50% for N and P partially because we lack the knowledge of what drives this process, being unknown its implications when simulating nutrient cycling. Based on our own analysis of global patterns of nutrient resorption from trait data, we developed a dynamic scheme of nutrient resorption for nitrogen and phosphorus driven by leaf structure, longevity and environmental factors, to be implemented in the QUINCY model. We present the concept behind this novel scheme through ecophysiological traits trade-offs, as well as first implications for ecosystem functioning. We show that we can better predict plant and soil nutrient dynamics at steady state and crucially, under altered climate and CO2 conditions. Plant internal nutrient cycling has cascading implications for ecosystem nutrient pools and fluxes, being an essential process in ecosystem models, that allows us to improve our predictions of the future and furthers our understanding of nutrient cycling processes.
Anthropogenic aerosol forcing has significantly weakened regional summertime storminess in the Northern Hemisphere in the satellite era
Authors: Shaw Tiffany , Kang Joonsuk , Sun Lantao
Published: March 2024

Reanalysis data show the summertime circulation in the Northern Hemisphere midlatitudes has weakened significantly in the satellite era. Recent work shows the circulation weakening is not significantly affected by Arctic Amplification and Arctic Sea ice loss, but did not examine the role of other anthropogenic forcings such as aerosols. Here we use Detection and Attribution Model Intercomparison Project (DAMIP) simulations, which capture the weakening trend in reanalysis data, to quantify the impact of anthropogenic forcing due to aerosols and greenhouse gases. The DAMIP simulations show aerosol forcing dominates the weakening of the circulation across the Eurasia-Pacific sector, including the Pacific jet and storm track. Aerosol and greenhouse gases contribute equally to weakening the Atlantic jet and storm track. We use an energetic framework to understand the impact of aerosols on the storm track. In particular we show aerosol forcing leads to an increasing surface shortwave radiation trend over Western Europe and a decreasing surface shortwave trend over South and East Asia. These shortwave trends induce a weakening trend of the equator-to-pole energy gradient that leads to a weaker downstream storm track. Overall, our results show aerosol forcing is a dominant factor in regional circulation trends during Northern Hemisphere summertime in the satellite era. They have important implications for interpreting summertime heatwave trends in the Northern Hemisphere midlatitudes during summertime.
Unveiling Geological Patterns: Bayesian Exploration of Zircon-Derived Time Series Data
Authors: Qian Hang , Tian Meng , Zhang Nan
Published: March 2024

For its immunity to post-formation geological modifications, zircon is widely utilized as chronological time capsule and provides critical time series data potential to unravel key events in Earth’s geological history, such as supercontinent cycles. Fourier analysis, which assumes stationary periodicity, has been applied to zircon-derived time series data to find the cyclicity of supercontinents, and wavelet analysis, which assumes non-stationary periodicity, corroborates the results of Fourier Analysis in addition to detecting finer-scale signals. Nonetheless, both methods still prognostically assume periodicity in the zircon-derived time-domain data. To stay away from the periodicity assumption and extract more objective information from zircon data, we opt for a Bayesian approach and treat zircon preservation as a composite stochastic process where the number of preserved zircon grains per magmatic event obeys logarithmic series distribution and the number of magmatic events during a geological time interval obeys Poisson distribution. An analytical solution was found to allow us to efficiently invert for the number and distribution(s) of changepoints hidden in the globally compiled zircon data, as well as for the zircon preservation potential (encoded as a model parameter) between two neighboring changepoints. If the distributions of changepoints temporally overlap with those of known supercontinents, then our results serve as an independent, mathematically robust test of the cyclicity of supercontinents. Moreover, our statistical approach inherently provides a sensitivity parameter the tuning of which allows to probe changepoints at various temporal resolution. The constructed Bayesian framework is thus of significant potential to detect other types of trend swings in Earth’s history, such as shift of geodynamic regimes, moving beyond cyclicity detection which limits the application of conventional Fourier/Wavelet analysis.
Peatland IPCC emission factors in the light of new EC carbon flux time series
Authors: Behrens Nicolas , Knorr Klaus-Holger , Gharun Mana
Published: March 2024

Peatlands are the world’s largest storage of soil organic carbon. While natural peatlands act as sinks of atmospheric carbon, drainage and disturbance (e.g., due to land use and climate change) turn peatlands into net carbon sources. Greenhouse gas (GHG) emissions from drained peatlands are therefore part of national GHG-emission reports, guided by the IPCC wetlands supplement. Herein, default emission factors (EF) are defined both for drained and rewetted peatlands, the former split into tropical and boreal/temperate wetlands, the latter further sub-categorized into nutrient poor and rich peatlands. These default emission factors are to date largely based on a limited number of static chamber-based studies, many measured over relatively short periods of time (1-3 years). As carbon flux measurements on peatlands have gained more attention, recent publications have added several new datasets to the EF calculations, significantly reducing the EF and narrowing confidence intervals. However, the final values are still almost entirely derived from chamber-based measurements with inherent limitations and uncertainties.
The Eddy-Covariance (EC) method is an alternative, established method to quantify carbon fluxes from ecosystems, spatially and temporally integrated (typically every 30 min throughout the year, representing a “flux-footprint” covering a whole ecosystem). As EC-based measurements are increasingly applied and such data are now available from several disturbed peatlands over several years, it is plausible to revise the default EFs. In this study we compile global EC time series for CO2 fluxes from disturbed peatlands of different land use categories with a focus on drained and rewetted peatlands affected by no or by  minor extensive management practices.  We investigate the diurnal, seasonal and annual variability of the fluxes. The net carbon emissions are compared to the EFs currently in use. With available ancillary data such as climate, water table depths, nutrients, ecosystem type and (succession-) state of the ecosystem we asses controlling factors for carbon fluxes. This investigation yields important context to evaluate the uncertainty and reliability of default emission factors for disturbed peatlands. Additionally, we apply a process-based model (CoupModel) to an own study-site to generate a higher-tier emission factor, including seasonality and climate variations.
Numerical simulations of sediment yield and terrain changes by water erosion using a processed-based model
Authors: Wang Jia-Tsung , Chang Kao-Hua , Wang Yung-Chieh
Published: March 2024

This research presents numerical simulations of small-scale rainfall simulator experiments using a process-based physical model. The model utilizes fundamental physical equations and analyzes the phenomena of surface runoff and water erosion. The adopted physical model is primarily composed of the shallow-water wave equation, Green-Ampt infiltration formula, and Hairsine-Rose equation. In the model, processes including water infiltration, splash erosion caused by rainfall, sediment entrainment carried by surface runoff, and sediment deposition are considered, aiming to simulate surface runoff, cumulative sediment yield, and eroded-terrain changes caused by water erosion. To assess the effectiveness of the numerical simulation results, the Nash-Sutcliffe efficiency coefficient (NSE) is used as the evaluation criterion. The laboratory rainfall simulator experiments using the same rainfall intensity (加入強雨強度) of three different slopes (10°、20° and 30°) were used as the studied cases Results of the simulations show that NSE values for runoff simulation reached 0.927 during the parameter calibration phase and exceeded 0.883 and 0.913 in the validation phases, respectively. The NSE for cumulative sediment yield simulation achieved 0.849 during parameter calibration and reached 0.997 and 0.983 in the validation phases. For cross-sectional microtopography simulation, the NSE attained 0.378 in the parameter calibration phase and achieveds 0.359 and 0.737 in the validation phases. In the case of longitudinal microtopography simulation, the NSE reached 0.937 during parameter calibration and attained 0.838 and 0.439 in the validation phase. This study presents the feasibility of the processed-based model in simulating surface runoff, sediment yield and eroded-terrain by water erosion.(Key Words: Surface runoff, Soil erosion, Shallow-water equation, Green-Ampt infiltration formula, Hairsine-Rose equation)
Sensitivity of millennial-scale climate oscillations to boundary conditions in HadCM3 glacial simulations
Authors: Snoll Brooke , Ivanovic Ruza , Gregoire Lauren , Rome Yvan , Sherriff-Tadano Sam
Published: March 2024

Romé et al. (2022) present a new set of long-run Last Glacial Maximum experiments with millennial-scale climate oscillations between cold and warm modes. These oscillations are triggered by different snapshots of ice-sheet meltwater derived from the early stages of the last deglaciation. The overall characteristics of the oscillating events share similarities with δ18O records of the last glacial period. We test the robustness of these oscillations under different climate conditions, i.e., changes in atmospheric carbon dioxide concentration and orbital configuration. These experiments were run with intentions to better understand the range of conditions the oscillations can be sustained within the model and provide additional insight into the triggering mechanisms that control abrupt climate changes. The results of our sensitivity analysis show that small changes in carbon dioxide concentrations can impact the periodicity and existence of oscillations. A decrease in carbon dioxide concentration decreases periodicity, and an increase in carbon dioxide concentration increases periodicity, leading to an end of the oscillations. Our results also show that for changes in orbital configuration, an increase in Northern Hemisphere summer insolation decreases periodicity and potentially also amplitude. The results show that small changes in climate conditions can impact the shape and existence of oscillations and how this could relate to the changing periodicity and amplitude of observed Dansgaard-Oeschger events as well as transitions from glacial to interglacial states.
Marine Heat Waves long-term trend assessment in the Northeast Atlantic region. 
Authors: Castrillo-Acuña Lluís , Martínez-Martínez Silvia , de Pascual-Collar Álvaro
Published: March 2024

Marine heat waves (MHWs) may be understood as prolonged periods of anomalously high sea surface temperatures (SST). These events are associated to impacts on marine ecosystems such as coral bleaching, mass mortality of marine invertebrates due to heat stress, rapid species’ migrations, fishery closures or quota changes, among others.The Iberia-Biscay-Ireland (IBI) region, covering from the Canary basin to the Celtic Sea, demonstrated for the year 2022 peak anomaly values of 15 MHWs events, 128 days of mean durations, and 261 total days of MHW according to a reference period from 1982 to 2022 (Castrillo-Acuña et al. 2024). The result of almost 300 days of MHW in some areas for the 2022 suggest that the current methodology may not be complete, as MHW are expected to be an extreme phenomenon. Global assessments such us Oliver et al. (2018) and Schlegel et al. (2019) had demonstrated the correlation between long term mean SST trends and some MHWs properties, but may this influence be strong enough to invalidate the results?In this study we present a sensitive experiment of the affection of long term mean trends of SST and MHW detection by using different detrending methods. Also considering different refence periods.  It is performed in the IBI domain which covers upwellings, straits, bays, continental shelfs, open waters, etc. The study aims to investigate how the presence of medium to long-term trends may condition the MHW properties in different key oceanographic areas. In this way, we can differentiate regions where the variability of MHW is not conditioned by SST trends from those where it is and its magnitude.        Castrillo-Acuña, L., Alonso-Valle, A., de Pascual-Collar, A.: Characterization of Marine Heat Waves in the IBI Region in 2022. Manuscript submitted to the 8th edition of the Copernicus Ocean State Report (OSR8), Copernicus Publications, State Planet, 2024. Oliver, E. C. J., Donat, M. G., Burrows, M. T., Moore, P. J., Smale, D. A., Alexander, L. V., Benthuysen, A., Feng, M., Sen Gupta, A., Hobday, A. J., Holbrook, N. J., Perkins-Kirkpatrick, S. E., Scannell, H. A., Straub, S. C., and Wernberg, T.: Longer and more frequent marine heatwaves over the past century. Nature Communications, 9(1), Article 1. https://doi.org/10.1038/s41467-018-03732-9, 2018. Schlegel, R. W., Oliver, E. C. J., Hobday, A. J., & Smit, A. J. : Detecting Marine Heatwaves With Sub Optimal Data. Frontiers in Marine Science, 6.    https://www.frontiersin.org/articles/10.3389/fmars.2019.00737, 2019.
Shock-tube experiments and high-speed Schlieren shadow photography for low viscosity analogue materials
Authors: La Spina Giuseppe , Taddeucci Jacopo , Spina Laura , Pennacchia Francesco , Scarlato Piergiorgio
Published: March 2024

Volcanic eruptions show a wide range of eruptive stiles, from low intensity effusive eruption to energetic and powerful explosive eruptions. Different styles of activity can be also seen during the same volcanic eruption, particularly when low viscosity magmas, such as basalts, are involved. Yet, the conditions by which fragmentation of basaltic magmas is achieved (and thus the generation of explosive eruption) are not fully understood. This poses a real challenge to policymakers tasked with mitigating the risks associated with eruptions of basaltic volcanoes.In order to better understand the fragmentation of low viscosity magma, we employed a brand new apparatus combining a shock-tube apparatus together with a high-speed Schlieren shadow photography and acoustic sensors.We present preliminary results obtained with this new apparatus performing experiments either with water or different analogue materials. We performed experiments varying also parameters, such as the length and the diameter of the conduit, the fractal dimension of the tube and the pressure gradient.
A Statistical Study of the Properties of and Geomagnetic Responses to Large, Rapid Southward Turnings of the Interplanetary Magnetic Field
Authors: Lazzeri Chiara , Forsyth Colin , Samsonov Andrei , Branduardi-Raymont Graziella , Bogdanova Yulia
Published: March 2024

The interplanetary magnetic field (IMF) north-south component, Bz, plays a crucial role in the interaction between the solar wind and the Earth's magnetosphere. We analyse 98 intervals in which Bz changed from > 3 nT to < -3 nT in 5 min and for which these rapid southward turnings (STs) were surrounded by consistently northward or southward IMF.This analysis is performed separately for events in proximity of interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs). We find that IMF magnitude, solar wind dynamic pressure and proton density (but also flow speed and plasma pressure in ICME-associated events) are enhanced above their median values. We analyse the maximum responses of the SML, SMU, SYM-H and PC magnetospheric indices and their timescales, but also the occurrence of geomagnetic phenomena. We find that magnetic storms followed 46.94% of events, with the strongest storms (with median SYM-H -120 nT) following ICME turnings. STs were followed by either substorms (60.20%) or enhanced convection (37.76%). While SML has similar average minima (~ -460 nT) and timescales (~ 56 min) for substorm and convection events, SMU has noticeable differences. PCN is found to have peaks (3.8 mV/m) around 30 minutes after the turning, and larger ones (4.9 mV/m) later. Stronger solar wind driving and magnetospheric responses are observed in ICME turnings. Examining the correlation between the geomagnetic and solar wind parameters around STs, reveals a more direct link between solar wind driving and geomagnetic response for STs than at other times.
Application of climate risk assessment framework for selected Italian airports: a focus on extreme temperature and extreme precipitation events
Authors: De Vivo Carmela , Barbato Giuliana , Ellena Marta , Capozzi Vincenzo , Budillon Giorgio , Mercogliano Paola
Published: March 2024

Due to increased extreme weather events as a consequence of climate change, climate risk analysis has become an essential issue for all critical infrastructures, including airports. The aim of this study is to apply a climate risk assessment framework to evaluate the impacts of extreme temperatures and extreme precipitation events on several Italian airports: Malpensa, Linate, Bergamo, Ciampino, Fiumicino, Napoli, Catania, Palermo, and Cagliari. According to the risk definition recommended in the Sixth Assessment Report of IPCC (2022), specific hazard, exposure and vulnerability indicators were identified. The hazard indicators were calculated using the UERRA regional reanalysis for the observed period (1981-2010). The climate variations were evaluated by an ensemble mean of high-resolution climate projections from the EURO-CORDEX initiative for the short (2021-2050), medium (2041-2070), and long-term future period (2071-2100), under RCP 2.6, RCP 4.5, and RCP 8.5 scenarios. Exposure and vulnerability data were collected from multiple sources, such as official airports documents or websites. The final risk index obtained from the combination of these three factors allowed us to identify which of the selected airports are probable to face the major impacts due to extreme temperature and precipitation events.In addition, starting from this study, a further innovative methodology is currently being evaluated to be adopted for climate change risk assessment by an individual airport. Main steps of this procedures involve the identification of hazard indicators, exposure and vulnerability factors. The success of the analysis performed is closely linked to the ability to actively involve the airport managers/operators through the participation to the workshops as well as the compilation of specific questionnaires in order to establish a participatory process with the aim to provide a comprehensive and detailed analysis.All the methods and analysis (planned and ongoing) have the main goal of supporting the risk assessment airports and providing key information to enable the definition, selection and implementation of appropriate adaptation strategies in relation to characteristics of the airports and then to improve their resilience to climate change.
Seasonal Diversity of Indo-Pacific Warm Pool Volume Expansion: The Role of Climatological Subsurface Temperature Patterns
Authors: Gan Qiuying , Leung Jeremy Cheuk-Hin , Dong Wenjie , Wang Lei , Li Weijing , Qian Weihong , Zhang Banglin
Published: March 2024

The Indo-Pacific warm pool (IPWP) expansion under global warming has huge impacts on global climate. While recent studies have revealed the seasonal diversity of IPWP surface expansion and its impacts under greenhouse warming, understanding the changes in seasonality of the IPWP volume is of greater importance, especially given the crucial role of subsurface ocean temperature in climate systems. This poster presents the seasonal diversity of Indo-Pacific warm pool volume expansion.In this study, we find a significant difference of IPWP volume expansion rate across seasons from 1950–2020, although the oceanic warming is rather seasonally uniform. The expansions of IPWP volume during boreal autumn and winter are faster compared to boreal spring and summer. This consequently weakens the seasonality of IPWP volume, particularly in the upper-layer, with a significant decreasing trend of -0.54×107 km3/decade. Further analyses suggest that this seasonal diversity in IPWP volume expansion is primarily caused by the seasonality of capacity for IPWP volume change, which is determined by the seasonal climatological subsurface temperature pattern over the Indo-Pacific Ocean. Furthermore, these variations may exert varied impacts on the troposphere and East Africa precipitation in rainy seasons. Namely that the larger expansion of IPWP in short rains is more closely related to the enhanced ascending motion and increased precipitation over East Africa, comparing with the long rains. This study emphasizes the crucial impacts of climatic subsurface Indo-Pacific Ocean temperature properties on the change of IPWP volume seasonality, which may have crucial effects on the precipitation in East Africa rainy seasons, and may hold important clues about how greenhouse warming affect oceanic seasonal cycle.