bluuebunny/crossref_metadata_2025 huggingface dataset:
Intensifying circumpolar winds contributes to reducing winter Antarctic sea ice growth
Authors: Topal Daniel , Fichefet Thierry , Massonnet François , Barthélemy Antoine , Goosse Hugues , Dalaiden Quentin , Barriat Pierre-Yves
Published: March 2024

During the austral autumn/winter of 2023 Antarctic sea ice exhibited a pan-Antarctic wide delay in refreezing of roughly a month (peaked in July 2023, hereafter referred to as W23 event). As such it is unprecedented over the satellite era and may point to a start of a transitioning to a new state of Antarctic sea ice. However, the relatively short observational record obscures our understanding how natural variability in Antarctic sea ice can act together with anthropogenic climate change in creating favorable conditions for extreme Antarctic sea ice changes. Here we show that an anomalous atmospheric circulation pattern prior to W23 (May-to-July 2023) is part of a longer-term (1979-2022) trend in observed mid-to-upper tropospheric winds around the Antarctic continent towards a wavier manner that favors anomalous moisture transport to the Weddell Sea. We further show that this circulation pattern is associated with winter sea ice anomalies on both year-to-year and interdecadal timescales in preindustrial control simulations of CMIP6 climate models as well as in future projections of large ensemble simulations under greenhouse gas emission scenarios. By conducting standalone simulations with the global ocean-sea ice model NEMO4-SI3 (forced by the atmospheric reanalysis ERA5) at two horizontal resolutions (1º & 0.25º), we also study the influence of the recently observed acceleration of ocean warming around the Antarctic continent and the effect of model horizontal resolution on the simulation of sea ice extremes. Our results overall suggest that internal atmospheric-sea ice coupling could be an important contributor to future winter Antarctic sea ice changes, enhancing the forced Antarctic sea ice changes that are primarily driven by ocean warming.
Electrical Conductors Beneath Mt. Erciyes Imaged by Three-dimensional Modeling of Magnetotellurics Data
Authors: Yazıcı Ruken , Tank Sabri Bülent , Üner Serkan , Karaş Mustafa
Published: March 2024

Earlier studies propose that the volcanic activity embodying the polygenetic Mt. Erciyes in the Cappadocian Volcanic Province (CVP), Central Anatolia, Türkiye, transpired as an inevitable product of the post-collisional extension experienced along two entities, the Anatolide-Tauride Carbonate Block, and the Central Anatolian Crystalline Complex (CACC). With its sixty-four monogenetic vents, Mt. Erciyes is the highest and most voluminous (3300 km2) stratovolcano in Central Anatolia with its summit reaching as high as 3917m. Strain-partitioning played a key role in the formation of the fault systems and the Erciyes basin that favored the evolution of the volcano. During three survey campaigns conducted in 2013, 2014, and 2018, a total of thirty-eight wide-band magnetotellurics (MT) observations were systematically made unravel the electrical structure beneath the Erciyes stratovolcano complex and the adjacent Erciyes basin, as part of a research initiative funded by the NSF under the title Continental Dynamics / Central Anatolian Tectonics (CD/CAT). Defining the boundaries of the Erciyes volcanic complex, the basin exhibits prominent substantial, particularly three major faults, the Yeşilhisar, Develi and Gesi Faults, with the two of them framing the western and eastern edge and the last delineating runs in the middle of the basin. The Gesi Fault crosses from the central part of the basin and acts as the main branch of the wider Central Anatolian Fault (CAF) Zone. Based on geological evidence, the volcano developed in the Pliocene and Quaternary in two stages. These are the (i) Koç Dağ (>2.8 Ma) and the (ii) New Erciyes (
Investigating periods and regions with large mitigation potential using algorithmic climate change functions 
Authors: Dietmüller Simone , Matthes Sigrun , Frömming Christine , Peter Patrick , Dahlmann Katrin
Published: March 2024

Planning climate-optimized aircraft trajectories requires temporally and spatially resolved quantitative estimates of the climate effects of aviation emissions. Algorithmic climate change functions (aCCFs) are applied, which efficiently assesses the climate effects of CO2 and individual non-CO2 effects (i.e. nitrogen oxide (NOx) induced ozone, methane and PMO, water vapour, and contrail-cirrus) using meteorological input data at the time and location of the emission. A consistent set of initial prototype aCCFs (aCCF-V1.0) has recently been made available (Yin et al., 2023), and an updated formulation of this aCCFs calibrated towards the climate response model AirClim has been developed (aCCF-V1.0A, Matthes et al., 2023).Utilizing the recently published open source Python Library CLIMaCCF (Dietmüller et al., 2023), we calculate aCCFs for individual and merged non-CO2 climate effects for a variety of different summer and winter weather patterns over the North Atlantic flight corridor as well as over the European airspace. The calculations are based on meteorological data from the ERA5 reanalysis dataset. Through a detailed analysis of these aCCFs, we identify meteorological conditions with large non-CO2 climate effects and demonstrate the influence of these identified weather patterns on the mitigation potential.We use ensemble members to systematically characterize the uncertainties arising from the limited predictability of weather forecasts for the weather patterns identified above. This allows to access the robustness of the climate effect estimates (and their mitigation potential). Moreover, we investigate the sensitivity of using different physical climate metrics and efficacy parameters and thus provide further insight to uncertainties linked to climate science.We further investigate the dependence of aCCF patterns to differently resolved meteorological input data (temporal, spatial, and vertical variation). Based on this analysis, we provide recommendations regarding the level of complexity for such an advanced MET service. Additionally, sensitivity studies using meteorological data from different data products (i.e. archived historical forecast) are shown.Acknowledgement: The current study has been supported by the following projects: CICONIA, which has received funding from the European Union under grant agreement no. 101114613, CONCERTO, which has received funding from the European Union under grant agreement no. 101114785 and the BMWK LuFo project D-KULT 20M2111A.  
Deciphering seismic sequences with high-precision hypocenter locations, focal mechanisms, and waveform modelling
Authors: Lanza Federica , Diehl Tobias
Published: March 2024

To better understand seismotectonic processes and the associated seismic hazards within a region, it is imperative to explore the causality between earthquakes, active tectonics, and individual fault structures. Hypocenter locations represent a well-established method to identify active faults, their spatial geometry and temporal evolution. First motion focal mechanisms provide insights into source processes and fault kinematics, aiding in the reconstruction of seismic strain and seismogenic stress regimes. Waveform modelling is key to refine earth structure models and constrain source process parameters.Here, we present the challenging case of the seismic sequence of Saint-Ursanne of March and April 2000 in Switzerland, where we applied advanced seismological analyses to reduce uncertainties in hypocenter locations and focal mechanisms, commonly encountered in shallow seismicity. The sequence, consisting of five earthquakes of which the largest one reached a local magnitude (ML) of 3.2, occurred in the vicinity of two critical sites, the Mont Terri rock laboratory and Haute-Sorne, which has been approved as a site for the development of a deep geothermal project. Our results, combined with geological data, suggest that the sequence is likely related to a backthrust fault located within the sedimentary cover and shed new light on the hosting lithology and source kinematics of the sequence. These new findings provide new insights into the present-day seismotectonic processes of the Jura fold-and-thrust belt (FTB) of northern Switzerland and suggest that the Jura FTB is still undergoing seismically active contraction at rates likely
End-to-end Learning in Hybrid Modeling Systems: How to Deal with Backpropagation Through Numerical Solvers
Authors: Ouala Said , Chapron Bertrand , Collard Fabrice , Gaultier Lucile , Fablet Ronan
Published: March 2024

Artificial intelligence and deep learning are currently reshaping numerical simulation frameworks by introducing new modeling capabilities. These frameworks are extensively investigated in the context of model correction and parameterization where they demonstrate great potential and often outperform traditional physical models. Most of these efforts in defining hybrid dynamical systems follow offline learning strategies in which the neural parameterization (called here sub-model) is trained to output an ideal correction. Yet, these hybrid models can face hard limitations when defining what should be a relevant sub-model response that would translate into a good forecasting performance. End-to-end learning schemes, also referred to as online learning, could address such a shortcoming by allowing the deep learning sub-models to train on historical data. However, defining end-to-end training schemes for the calibration of neural sub-models in hybrid systems requires working with an optimization problem that involves the solver of the physical equations. Online learning methodologies thus require the numerical model to be differentiable, which is not the case for most modeling systems. To overcome this difficulty and bypass the differentiability challenge of physical models, we present an efficient and practical online learning approach for hybrid systems. The method, called EGA for Euler Gradient Approximation, assumes an additive neural correction to the physical model, and an explicit Euler approximation of the gradients. We demonstrate that the EGA converges to the exact gradients in the limit of infinitely small time steps. Numerical experiments are performed on various case studies, including prototypical ocean-atmosphere dynamics. Results show significant improvements over offline learning, highlighting the potential of end-to-end online learning for hybrid modeling.
Provenance of the North Eastern Carpathian thrust sheet deposits based on geochronology
Authors: Lazar Constantin , Roban Relu Dumitru , Ducea Mihai
Published: March 2024

In the northernmost part of the Romanian Carpathians, the Maramureș region exposes several tectonic units comprising remnants of the Mesozoic Ceahlău - Severin Ocean. The “Black Flysch” unit contains a mafic complex extended in the Middle – Late Jurassic interval. These are covered by Upper Jurassic–Lower Cretaceous sediments, which include deep-water carbonates and siliciclastic deposits in the “Black Flysch” Nappe and mainly turbidites in the Ceahlău unit, which belong to the Outer Dacide nappe system.The U-Pb age distribution spectra of detrital zircons obtained from the samples collected from the “Black Flysch” and Ceahlău tectonic units exhibit similarities within the range of 180–3,000 Ma. Significant peaks have been noticed at around ~460, 580–620, ~320, 180–200, and 950–1,100 Ma. Within the ‘Black Flysch’ Nappe prevail Ordovician ages (~460 Ma) associated with the Bucovinian Nappe basement. Conversely, in the Ceahlău Nappe, the Late Neoproterozoic peak (~600 Ma) holds greater significance, corresponding to the sediments of the Eastern European Platform and the paragneiss of the Bucovinian Nappe. The East European Craton contributes insignificantly as source area, given the minimal percentage of inherited ages surpassing 1 Ga.
Changes in climate extremes over the European Forest Types (1991-2050)
Authors: Cheval Sorin , Gianetti Francesca , Collalti Alessio , Dumitrescu Alexandru , Neumann Mathias , Tudose Nicu Constantin
Published: March 2024

A forest type (FT) generally describes a category of forest defined by its composition, and/or site-specific factors, and used in a system suitable to the situation at country level. The FTs are recognised to be a flexible approach to support the collection of data and organise forest indicators in a given area at different spatial scales, from country up to continental level.The ongoing climate change is associated with increased intensity, duration and spatial extent of climate extremes, which may exacerbate the impacts on many ecological systems and socio-economic sectors, including  forest ecosystems and forest management.This study explores the observed variability (1991-2020) and estimated changes (2021-2050) in the climate extremes that may occur over the European Forest Types (EFT), to provide a continental-scale perspective of the potential impact on forest ecosystems and provide decision support for forest management. Both temperature and precipitation CLIMPACT extremes indices relevant for forestry described and proposed by the Expert Team on Sector-Specific Climate Indices were computed using CERRA sub-daily regional reanalysis data for Europe. We use model outputs of climate change projections based on two Representative Concentration Pathways (i.e., RCP4.5, and RCP8.5). The climate information was analysed in combination with the 100 m resolution gridded EFT dataset produced within the Horizon Europe project OptFor-EU, ensuring consistency with similar studies at the European level. The results are detailed for case study areas situated in eight European countries (Norway, Lithuania, United Kingdom, Germany, Austria, Romania, Spain, and Italy).While all EFTs are subject to increasing temperatures extremes and precipitation intensities, we found clear regional differences. The continental coverage and the level of details provided by these results support both the development of EU adaptation and mitigation strategies and plans, as well as the local forest management practices within the climate change context.AcknowledgementsThis research received funds from the project “OPTimising FORest management decisions for a low-carbon, climate resilient future in Europe (OptFor-EU)” funded by the European Union Horizon Europe programme, under Grant agreement n°101060554.
Shutdown of Atlantic Meridional Overturning Circulation Induced by Precession
Authors: Liu Yonggang , Liu Haobo
Published: March 2024

The weakening or shutdown of Atlantic Meridional Overturning Circulation (AMOC) likely played a significant role in the glacial inception during the past million years. Previous modeling studies have shown that orbital forcing could have been triggered multiple AMOC weakening or shutdown, but it is still unclear which orbital parameter is the most essential trigger. In this study, we performed multiple long simulations with a fully coupled atmosphere-ocean general circulation model, CESM1.2.2, to investigate the influence precession on AMOC. It is found that precession is able to trigger a shutdown of AMOC. However, this happens only when the eccentricity is high and the atmospheric CO2 concentration is relatively low. The growth and expansion of Arctic sea ice is responsible for the shutdown. Therefore, the results may advance our understanding of the mechanisms driving the glacial-interglacial cycles of the Quaternary Period, and may be related to the mid-Pleistocene transition.
An integrated approach for water-quality investigation of Piediluco lake (Italy)
Authors: Di Francesco Silvia , Venturi Sara , Casadei Stefano
Published: March 2024

The study aims at investigating strategies to reduce the effect of the nutrients pollution in Piediluco lake, improving the water quality and limiting the eutrophication processes. In particular, managements options operating in the body of the reservoir are considered, i.e. the variation and/or repositioning of the main water inflow.Piediluco is the second largest lake of Umbria region (Central Italy) and is characterized by an extended and complex shape with several branches (approximately 1,7 km2 with an average and maximum depth, respectively, of 10 m and 20 m). Currently, the hydraulic regime of the lake  is regulated by the downstream hydroelectric plants of Galleto and Monte Sant’Angelo: during the power generation, water from Piediluco lake is conveyed through Velino river into the hydroelectric plant; when the electric production is paused, the entire flow rate of Velino river is conveyed to the lake. Actually, the largest water supply is provided to the lake by the Medio-Nera channel, an artificial canal built in 1932 that has expanded the Piediluco basin area from 75 km2 to 2100 km2. The main idea is to move the position of the inlet in order to promote the movement and recirculation of water throughout the lake surface.Several field measurements, carried out from the first years of 1980s, have highlighted that the health of the lake has been constantly deteriorating: the increase of nutrients loading has negatively affected the ecosystem, progressively compromising the use of the lake and its resources, and, consequently, the local economy. A high eutrophication level of the lake, with algal bloom and, in extreme meteorological conditions, a significant water anoxia, in particular in the arms of the lake far from the inlet of Medio-Nera channel, have been observed.The work is based on an integrated approach: at first stage, remote sensing available data, coupled with the Google Earth Engine (GEE) platform, are used to analyse, in the last decade, the spatial distribution, the seasonal variations and the inter-annual variations of water quality parameters. Secondly, a two-dimensional model is developed, in order to simulate the sediment and pollutant transport connected with the hydrodynamic condition of the lake with different management scenarios. The model is calibrated and validated on the base of in situ monitoring data.
Remotely sensed assessment of Urmia Lake drying up; Climate change or anthropogenic effects?!
Authors: Dalvi Marjan , Rousta Iman , Olafsson Haraldur
Published: March 2024

Urmia Lake is the largest hypersaline lake in Western Asia and it is currently facing severe desiccation. Immediate action is necessary to prevent irreversible damage to the environment and economy. The lake covers the majority of the Urmia Lake watershed. This study aimed to analyze the changes in Land Surface Temperature (LST) during the day and night in the area using MODIS 1 km, 8 days, version 061 (MOD11A2) images. The study also looked at water level variations using TOPEX/POSEIDON and Jason 1, 2, and 3, and precipitation variations using CHIRPS images from the period of 2001-2023. The results indicate that the water level of Urmia Lake has significantly declined by about 10 meters in the last few decades. Approximately 95 percent of the lake has dried up. The continuous declining trend of the water level started in 2001 and has led to an increase in LST day, about 0.03 ℃/year, and a decrease in LST night, about 0.07 ℃/year. Precipitation variations did not show any significant trend during the study period. Due to the high salt content caused by the lake drying up, the area is becoming a center for salty dust that can negatively affect the surrounding habitats. The trend of precipitation variations suggests that climate is not the primary factor responsible for the lake's desiccation.
Climate change has increased fire PM2.5 and its associated health burden
Authors: Park Chaeyeon , Takahashi Kiyoshi , Fujimori Shinichiro , Jansakoo Thanapat , Burton Chantelle , Huang Huilin , Kou-Giesbrecht Sian , Reyer Christopher , Mengel Matthias , Burke Eleanor
Published: March 2024

Climate change has influenced fire activities, altering the fire risk associated with air pollution and human health. However, the specific contribution of climate change to fire risks on air pollution and health burden has not yet been discovered. In this study, three fire-vegetation models were employed to simulate fire aerosol emissions under two simulations over the past six decades: an observation climate scenario and a counterfactual scenario where the long-term climate change trend is removed. Combining fire aerosol emissions with a chemical transport model and an avoidable mortality risk model, we calculated global fire PM2.5 and its associated mortality. By comparing the results under the two simulations, we demonstrated the climate change has increased the fire PM2.5 and its mortality. The findings indicated an increase in fire mortality over the six decades: 46,401 in the 1960s and 98,748 in the 2010s, with 3-8% attributed to climate change. Clear relationships were observed between the contribution of climate change to fire mortality and relative humidity or air temperature in some regions. This suggests that fire risks in these regions are sensitive to climate change and necessitate the development of adaptation strategies to mitigate risks in the future.  
The role of hemispheric flow patterns and land-atmosphere interactions in South Asian Heatwaves
Authors: ullah waheed , Wang Guojie , Fiifi Tawia Hagan Daniel , Ullah Safi , Samuel Bhatti Asher , Karim Aisha , Nooni Isaac Kwesi
Published: March 2024

In South Asia (SA) heatwaves during spring season have become a reoccurring phenomenon in the recent decade with severe socioeconomic losses reported and unprecedented ecosystem losses. More than 24% of the global population and 3.85% of global GDP (as of 2021) is exposed to severe heatwaves during pre-monsoon season. In this study, we explored the physical process and mechanism triggering these events and those amplifying these heatwaves. We used the ERA5 reanalysis data from the ECMWF and a suit of statistical and process-based techniques to understand the physical mechanism of the heatwaves in SA. We discovered that the heatwaves occur during April and May and end in early June. The heatwaves are comprised of two stages including the early stage where thermal stress exists followed by absolute heat driven by high temperature and energy accumulation. The zonally transmitted meridionally oscillating quasi-resonant Rossby waves transport energy and momentum into SA triggering the heatwave and control the early stage of the heatwaves. Afterwards when the soil moisture is depleted due to higher evaporative demands the strong land-atmosphere coupling exerts positive feedback and amplifies the second stage of the heatwaves.         
Paleogeographic reconstruction and sedimentary evolution of tidal-dominated estuarine depositional systems: Insights from ancient deposit records of the Oriente Basin M1 Sandstone
Authors: Zhu Sicheng , Sun Panke , Xu Huaimin
Published: March 2024

Tidal-dominated estuaries are a type of depositional system that is highly dynamic under the influence of tides. The interaction intensity between fluvial, tidal, and wave currents varies vertically along the coastline, resulting in a unique pattern of longitudinal gradient changes of facies associations and sediment distribution. Compared to river and delta sediments, research on ancient estuarine sediments is relatively limited. In this study, we analyzed observable data from the Late Cretaceous M1 Sandstone formation in the central northern region of the Oriente Basin, conducted in-depth research on its sedimentary characteristics, and proposed a tidal-dominated estuarine sedimentary model of this region. The rich core data provides reliable support for identifying sedimentary sequences of tidal environments, identifying a total of 14 lithofacies and 6 main types of facies associations, including tidal sand bars, tidal channels, and four types of tidal flats. These 6 types of facies associations correspond to the sediment accumulation characteristics in different sedimentary zones of the estuary, reflecting the differences in hydrodynamic conditions during the sedimentation process, such as strength, combination, and directionality. Furthermore, under the constraint of a dense well network, a detailed study of the stratigraphic pattern and deposit thickness was conducted to establish a matching relationship between sediment distribution characteristics and hydrodynamic characteristics in the entire region, providing sedimentary evidence for identifying tidal-dominated estuaries. Additionally, based on the combination relationships of tidal sequences, it was determined that there is a set of short-term sea level rise-fall cycles during episodic marine transgressions. The facies change of estuaries is sensitive to the response of sea level fluctuations. The results indicate that tidal sand bars are generally developed at the bottom of the tidal sequence. As the sea level decreases, the outer area is gradually covered by the tidal flat, of which the periodicity of the interior is clearer than that of tidal sand bars. Our research indicates a transition process from estuaries to deltas in the tidal system of M1 Sandstone formation under the influence of sea level fluctuations. The results provide evidence for a better understanding of the evolution of estuarine sediments in ancient strata.
Global model simulations on the impacts of aviation-induced aerosol on clouds and climate
Authors: Righi Mattia , Hendricks Johannes , Beer Christof , Brinkop Sabine
Published: March 2024

The current understanding of the impact of aviation-induced aerosol on the microphysical properties of clouds and the resulting climate effects is still regarded as highly uncertain. In this study, a global aerosol-climate model is applied to quantify (i) the impact of aviation-induced soot on cirrus clouds, and (ii) the impact of aviation-induced particles on low-level liquid-phase clouds. For the soot-cirrus effect, a radiative forcing in the range of −35 to 13 mW m−2 is simulated, depending on the assumed ice nucleating properties of aviation soot, but with a low statistical significance in several cases. A comparison with previous studies shows a general lack of consensus, which could not be reconciled even within the broad range of assumptions on the ice nucleating properties of aviation soot examined with the model. The effect of aviation-induced particles on low-level clouds results in a radiative forcing of –64 mW m-2 for present-day conditions in the CMIP6 emission inventory, and of –126 to –83 mW m-2 in 2050 under different scenarios. This mostly confirms the estimates of previous studies, although these are very sensitive to the assumed size distribution of emitted particles and to the fuel sulfur content of the aviation fleet. The main uncertainties behind these cloud effects are explored in the context of the existing literature and suggestions for refined estimates are discussed.
Magnetic Field Structures in the Near-terminator Induced Magnetospheres of Venus and Mars
Authors: Xiao Sudong
Published: March 2024

Venus and Mars, our two neighboring planets, have no global intrinsic magnetic fields, and the induced magnetospheres are formed in their solar wind interactions through mass loading of magnetic flux tubes carried by the solar wind and draping around the highly conducting ionosphere. Although they have similar global magnetic environments in their induced magnetosphere controlled by the interplanetary magnetic field and the solar wind motional electric field, their differences in planetary size, solar wind conditions, crustal magnetic fields, etc. also have measurable impacts. We comparatively study the magnetic field structures in the Venusian and Martian induced magnetospheres near the terminator via observations. The nature of their current systems and the features of magnetic structures such as flux ropes are examined in the near-terminator space and the effects of solar activity, interplanetary magnetic field, and crustal fields are explored. The results reveal the solar wind interaction with unmagnetized planets near the terminator, and a simulation provides a three‐dimensional view.
Exploration of IOCG deposits in Queensland, Australia using geophysical models of Ernest Henry copper mine
Authors: Sakhaeyan Faraz , Abtahi Forooshani Sayyed Mohammad , Sadeghisorkhani Hamzeh
Published: March 2024

The  Ernest Henry copper mine is one of the main Australian copper resources and a typical Iron Oxide Copper Gold (IOCG) deposit case. These deposits have specific geophysical signatures, e.g., considerable magnetic susceptibility and low resistivity due to magnetite mineralization. This research studies the geophysical models estimated via the inversion of magnetic and magnetotelluric in the Ernest Henry mine area. We also conducted these inversions in two other areas close to the Ernest  Henry mine, named A and B, which show magnetic anomalies similar to the Ernest Henry mine. Then, we compared the estimated models in these areas with those in  Ernest Henry's area. Three-dimensional inversion of magnetic data using the Li and Oldenburg algorithm revealed masses with magnetic susceptibilities higher than 0.019, 0.048, and 0.011 in SI units in the Ernest Henry, A and B areas, respectively. All the masses were extending from the surface to depths of one to three kilometres. Next, impedance analyses of magnetotelluric data indicated a two-dimensional behaviour of the Earth up to a frequency of 1 Hz in all the areas. Also,  we conducted two-dimensional inversions of these data along a profile for each area. A comparison of the estimated resistivities demonstrated a relatively conductive mass with a resistivity of less than 30 ohmm at depths of 5 km and beyond in all three areas. These models also demonstrated a decrease in the resistivity along the fault lines within the ranges, corresponding to the location of masses with relatively significant magnetic susceptibility identified during the magnetic data inversions. Geochemical analysis of copper grade variations in exploratory boreholes drilled in areas A and B indicated an increase in copper concentration exceeding 400 ppm in both areas. The structure of the estimated geophysical models in areas A and B and those estimated in the Ernest Henry area is similar. Besides, geochemical analysis of copper grade in exploratory boreholes drilled in areas A and B indicated an increase in copper concentration exceeding 400 ppm in both areas. Therefore, we deduce the possibility of IOCG copper mineralization deposits similar to the Ernst Henry mine in areas A and B. Meanwhile, since the concentrations of probable mineralizations have occurred along a fault zone in all the models, we suspect that the mineralization likely originated from hydrothermal solutions. These solutions spread from fault lines adjacent to highly resistive intrusive masses to the surface, causing the mineralization of magnetite and copper ores.
To develop a statistical model for the analysis of heat wave intensity duration frequency curve for major climatic zones of India
Authors: Kumar Priyankar , Chakraborty Arun
Published: March 2024

A Heat-wave-Intensity-Duration-Frequency (HWIDF) curve is employed to establish the relationship between the intensity, duration, and frequency of heat wave incidents. This approach offers a more comprehensive understanding of heat waves by considering their intensity, duration, and frequency. The HWIDF curves for India's six climate zones, namely, The Arid zone, Semiarid zone, Montane, Humid subtropical zone, Tropical wet, and Tropical wet & dry zone, are considered for the study. These curves are used to evaluate the probability of encountering heat waves with varying levels of intensity and duration. They also help measure changes in heat wave intensities for different return periods in relation to the evolving climate. Subsequently, the MRI-ESM2-0 models were employed to assess the disparities in HWIDF (Heat Wave Intensity-Duration-Frequency) by comparing scenarios with and without human emissions. This analysis aimed to determine the specific impact of human activities on heat waves. The analysis shows that heat waves in arid zones, lasting from one to ten days, with maximum and average intensities of 44.32℃ and 36.56 ℃ or less, occur with a frequency of once every two years (probability=0.5). These heat waves have higher intensities compared to other zones. On the other hand, montane zones experience lower intensities compared to other zones. Our findings indicate that heat wave intensity poses a greater danger under historical conditions when compared to natural conditions, particularly over a span of five and ten consecutive days. The likelihood of experiencing severe heat waves in the Humid Subtropical and Montane zones is more or less compared to other zones. Hence, our study indicates that the rising probability of severe heat waves, in terms of their severity and duration, could be attributed to anthropogenic warming.
Vegetation Phenological Metrics and Accumulated Antecedent Precipitation (AAP) in dryland pastures.
Authors: Brieva Carlos , Rodriguez Jose , Saco Patricia
Published: March 2024

Vegetation dynamics in dryland systems is highly dependent on soil moisture availability. Arid and semi-arid ecosystems are under the pressure of climate change and are facing overgrazing and logging, leading to increased degradation and desertification. The drylands of Mendoza, Argentina, are fragile ecosystems devoted to cattle breeding on native bushes and rangelands. Livestock farming relies on the productivity of natural resources, closely related to the monthly, annual, and seasonal rainfall, which is a critical driver of vegetation productivity and dynamics. However, the limited availability of precipitation data from gauging stations prevents a detailed analysis of the relationship between rainfall and vegetation. Therefore, satellite-estimated rainfall becomes a valuable information source to overcome this constraint.This study aims to analyze the relationship between the antecedent accumulated precipitation (AAP) and the vegetation dynamics in terms of phenological metrics (Length of Growing Season – LGS; Peak of Growing Season – PGS; Amplitude of Growing Season – AGS) for four vegetation types in Southeast Mendoza, Argentina (Bush steppe with low land cover; Open Bush; Forest of Prosopis Flexuosa; and Psammophilous Grassland).Vegetation parameters were derived using the software TIMESAT from Savitzky-Golay smoothing NDVI series of MODIS-Terra (MOD13Q1 V6.1) over 20 years (June 2000 to May 2020) and then correlated to AAP estimated by satellite using GPM (Global Precipitation Measurement) considering three time periods: Spring (accumulated precipitation of September to December), Spring plus Summer (September to February) and the duration of the Growing Season of each vegetation type.All vegetation types showed a similar response and behavior regarding the AAP and vegetation dynamics metrics. The LGSs are similar, from 187 days for Psammophilous grassland to 198 days for Forest of Prosopis. However, there are differences at the start of the season. The PGSs (peak of NDVI) and the AGS show higher correlations to the spring and summer precipitation, while the LGS correlates to spring and accumulated precipitation during the growing season.This information can help manage cattle grazing, avoid overgrazing, and manage production sustainably. Tracking vegetation responses to rainfall in space and time is of utmost importance for managing the limited resources,
Decoupled responses of above- and belowground productivity stability to drought and clipping in an alpine meadow
Authors: Ma Fangfang
Published: March 2024

Extreme drought and land-use intensification pose significant threats to ecosystem stability. However, existing studies that assess ecosystem stability primarily focus on above-ground net primary productivity (ANPP) stability and overlook the importance of below-ground net primary productivity (BNPP) stability. Here, by manipulating five levels of precipitation treatment (1/12 P, 1/4P, 1/2P, 3/4P, and P) and clipping (unclipped vs. clipped) over 7 years (2016-2022) in an alpine meadow, we examined the response patterns and drivers of ANPP stability and BNPP stability to drought and clipping. The results showed that extreme drought decreased ANPP stability but moderate drought increased BNPP stability, which challenges the traditional view that extreme drought could destabilize ecosystem stability based solely on results from aboveground processes. Besides, clipping had no impacts on ANPP stability but reduced BNPP stability, and clipping differentially regulated the stability of above- and below-ground productivity in response to extreme drought in our study.  Furthermore, ANPP stability was primarily driven by species asynchrony rather than species richness, whereas dominant species stability contributed strongly to the variations in BNPP stability of this alpine meadow confronted with drought and clipping. This study provides compelling experimental evidence for the decoupling in responses of ANPP stability and BNPP stability to extreme drought and clipping. Our findings indicate that aboveground responses should not be a sole predictor of the whole ecosystem-scale consequences of extreme drought and clipping on ecological stability, and lay stress on the necessity of evaluating ecosystem stability from a whole ecosystem perspective.
Gas migration beneath Laacher See: acoustic imaging of shallow CO₂ in the sediment and water column
Authors: Albers Stijn , Vandorpe Thomas , Caudron Corentin , Schmidt Bernd , Ritter Joachim , Reicherter Klaus , De Batist Marc
Published: March 2024

The East Eifel Volcanic Field in the west of Germany has received increased scientific attention in recent years due to new findings on ongoing deep magma-related seismicity and regional uplift. Related CO2-degassing phenomena in the region have also been investigated, more specifically in and around the Laacher See volcanic lake, formed by a series of eruptions ca. 13 ka BP. Present-day degassing activity in the Laacher See caldera is most notably evidenced by several gas seeps (i.e. mofettes) in the lake and its surrounding shore, emitting CO2 of magmatic origin. During two surveys in 2019 and 2021, several geophysical techniques were used to image and monitor this CO2 seepage, both in the water column and in the sedimentary infill of the lake. A multibeam echosounder was used to locate gas flares in the water column, visible by their high backscatter intensity, as well as the bathymetric expression of gas escape features on the lake floor. Additionally, high-resolution seismic reflection profiles were acquired with different acoustic sources at different frequencies. These profiles were used to identify accumulated gas in the subsurface, evidenced by enhanced reflections and acoustic blanking.Our results show that accumulated gas is present at different depths in the lake subsurface, from ca. 2 m to more than 25 m below the lake floor, making it possible to map out areas with high concentrations of free gas at different levels. Locations of subsurface gas accumulations often coincide with areas that have a high concentration of gas flares in the water column. Furthermore, depressions resulting from gas escape (i.e. pockmarks) can be identified on the lake floor bathymetry, linking the upward migration of CO2 gas in the subsurface to the seepage in the water column. Our data confirm that gas is actively migrating through the sedimentary infill and water column of Laacher See and illustrate the need for monitoring these gas migration processes, which can ultimately contribute to a better volcanic hazard assessment in the Eifel region.
Modelling inundated area in wetlands combining satellite and hydrological data: A comparison of classical methods and machine learning algorithms
Authors: Collados-Lara Antonio-Juan , Aguilera Héctor , Pulido-Velazquez David , Pardo-Igúzquiza Eulogio , Baena-Ruiz Leticia , Gómez-Gómez Juan de Dios , Mejías Miguel , Grima Juan
Published: March 2024

Wetlands, which are systems with significant environmental value, can be very sensitive to global change. The inundated area of wetlands, reflecting water quantity, stands as a key variable in the decision-making process for evaluating sustainable management strategies in these ecosystems.Satellite optical sensors are effective for regional and global surface water monitoring. However, depending on the satellite, they may not offer a comprehensive long-term time series of inundated areas to study the effects of global change. This limitation arises from factors such as presence of clouds, sensor failure, low revisit time or spatial resolution, or recent launch. We propose leveraging hydro-climatological data to enhance and complement satellite-observed inundated area dynamics. In this approach, we evaluate the effectiveness of classical methods such as ARIMA and multiple regression models, along with advanced techniques like artificial autoregressive neural networks and other machine learning algorithms. The goal is to integrate covariate information and simulate extensive and continuous inundated area time series. This methodology is valuable not only for filling gaps in observational data but also for projecting the impacts of climate change on inundated area in wetlands.The suggested methodology was implemented in the Lagunas de Ruidera wetland area in south-eastern Spain. This region exhibits a significant natural interplay between groundwater and surface water, highlighting a conflict between groundwater-dependent ecosystems and groundwater extraction for irrigation. From January to June, the average observed inundated area is approximately 4.3 km². In summer, there is a reduction of about 13% in the surface water area, which is subsequently recovered during the autumn.Acknowledgments: This research has been partially supported by the project SIGLO-PRO (PID2021-128021OB-I00) funded by the Spanish Ministry of Science, Innovation and Universities and the project C17.i7.CSIC – CLI 2021-00-000 funded byEuropean Union NextGenerationEU/PRTR.
Aviation-induced aerosol particles within the UTLS: Properties and processing observed from the IAGOS-CARIBIC Flying Laboratory
Authors: Mahnke Christoph , Gomes Rita , Bundke Ulrich , Berg Marcel , Ziereis Helmut , Sharma Monica , Righi Mattia , Hendricks Johannes , Zahn Andreas , Petzold Andreas
Published: March 2024

The influence of aviation on atmospheric aerosol, its processing, and its implications for climate are still areas associated with significant uncertainties. We carried out an in-depth examination of the characteristics of atmospheric aerosols linked to aviation by analysing aircraft emissions observed during missions of the IAGOS-CARIBIC Flying Laboratory.Equipped with a wide variety of aerosol and trace gas instrumentation, the IAGOS-CARIBIC Flying Laboratory conducted 42 operational flights on a Lufthansa Airbus A340-600 passenger aircraft from July 2018 to March 2020. These flights included routes from Munich, Germany, to various destinations in North America, South Africa, and East Asia. We developed and implemented a method to automatically identify aircraft exhaust plumes based on the 1 Hz resolved NOy and aerosol data sets. Between 2018 and 2020, this method identified over 1100 distinct aircraft plumes, offering a robust statistical foundation and global perspectives on aviation's influence on aerosol and trace gas characteristics. For each plume, the measured parameters were further divided into their respective background and plume excess values.The analysis of the plume excess properties, such as the non-volatile aerosol fraction, shows similar characteristics independent of the emission altitude. Notably, the emitted aerosol predominantly existed as an external mixture in contrast to the mostly internally mixed background aerosol, even at a mean plume age of 1 to 3 hours. For the large accumulation mode particles (diameter > 250 nm) no enhancement above the background variability could be detected in the aircraft plume. Furthermore, we discuss the particle emission indices (EI's) derived from our aircraft plume analysis in comparison to the particle EI's used in global models and those reported from aircraft engine certification measurements.
Compound Coastal Flooding Drivers in the Pacific Northwest: Understanding Precipitation-Surge-Wave Interactions and Projected Changes
Authors: Fereshtehpour Mohammad , Najafi Mohammad Reza , Casas-Prat Mercè
Published: March 2024

Coastal regions face escalating threats under climate change, necessitating a comprehensive understanding of compound flooding dynamics. This study aims to investigate the interplay between precipitation, wind waves, and meteorologically-driven storm surge, assessing their joint behavior leading to compound coastal flood risks in the Pacific Northwest. We examined two approaches to capture all possible drivers leading to compound events, which may not necessarily result from the extreme conditions of individual marginal variables. First, we used a conditional approach and assessed the block maxima (BM) of each variable in conjunction with the corresponding values of the other variables. Second, a peak-over-threshold (POT) investigation was conducted to generate datasets where all variables exceed their 95th percentiles. To calculate the joint return period of coastal flooding drivers, we used the most appropriate marginal distributions commonly used in coastal engineering, including the Generalized Pareto Distribution (GPD) for the POT-based approach and the Generalized Extreme Value (GEV) distribution for the BM. Subsequently, we computed the joint probability distribution by fitting the best-suited copula to the datasets to capture the interdependencies between the drivers. Moreover, as meteorological drivers may change under global warming, we extended our analysis to consider future projections of surge, waves, and precipitation. This enabled us to examine changes in the aforementioned dependencies and return periods. Sub-daily time series of surge and wave heights were obtained from the Canadian Coastal Climate Risk Information System (CCCRIS) (https://cccris.ca/), which provides high-resolution (~250 m along coastlines) simulations driven by ERA5 reanalysis and future projections until 2100 under the RCP8.5 emission scenario driven by four different combinations of global and regional models, namely, CanESM2.CanRCM4, CanESM2.CRCM5-QUAM, MPI-ESM-MR.CRCM5-QUAM, and GFDL-ESM2M.WRF. For each grid point, the corresponding precipitation data is obtained from the nearest grid point of the respective climate models. We assessed the degree to which each driver contributed to the overall change in the joint return period of concurring extremes in coastal flooding. We also conducted an analysis to quantify the respective contributions of each driver’s projection and their dependence structure to the uncertainty in changes of return periods. This study leveraged high-resolution data that encapsulated the regional dynamic responses, which is pivotal for precisely evaluating climatic hazards and developing efficient adaptation schemes, thereby ensuring a more informed decision-making process for coastal management and engineering applications.