bluuebunny/crossref_metadata_2025 huggingface dataset:
Weakening of springtime Arctic ozone depletion with climate change
Authors: Friedel Marina , Chiodo Gabriel , Peter Thomas
Published: February 2023

Arctic ozone is subject to large interannual variability, and severe ozone minima can occur through chemical ozone depletion and dynamical variability. Such Arctic ozone minima have been shown to bear a great societal relevance due to their impacts on health and climate. Following the success of the Montreal Protocol, ozone depleting substances (ODSs) in the stratosphere are declining, implying an expected weakening of chemical ozone destruction. However, continuing greenhouse gas (GHG) emissions cool the stratosphere, which might lead to an enhanced formation of polar stratospheric clouds (PSCs) and thus more efficient chemical depletion of ozone. Due to these opposing processes, there is currently no consensus on the fate of Arctic ozone minima in future climate. Here, we investigate the future evolution of Arctic ozone minima over the 21st century under different emission pathways in simulations conducted for the Chemistry-Climate Model Initiative (CCMI), CCMI-1 and CCMI-2022, and constrain these projections based on the models’ skill in reproducing present-day Arctic ozone variability. We find a large model discrepancy in the magnitude of ozone minima under present-day climate, caused by biases in the underlying model climatology. Models that simulate large ozone minima in present-day climate generally have a cold bias, and consequently large concentrations of active chlorine species (ClOx); these are the models that project the largest decline in the magnitude of ozone minima in the future. Conversely, models simulating weak Arctic ozone minima under present-day conditions generally have a warm bias and small ClOx concentrations; these are models with the smallest sensitivity of ozone minima to changes in ODS and GHG emissions. Consequently, inter-model spread in the magnitude of springtime Arctic ozone minima is projected to decline in the future. Through comparison with reanalysis, we identify the most realistic models. These models show a weakening in stratospheric ozone minima of about 1 DU/decade and with little sensitivity to the GHG emission scenario, which is deemed as the most likely projection. Taken together, these results indicate that Arctic ozone minima will likely become weaker in the future, largely due to the decline in ODS abundances, while stratospheric cooling due to GHGs is expected to play a secondary role.
The Miragoâne seismic clusters in southern Haiti triggered by the Mw 7.2 Nippes earthquake of August 14, 202
Authors: Paul Sylvert , Monfret Tony , Courboulex Françoise , Delouis Bertrand , Deschamps Anne , Douilly Roby , Ambrois David , Symithe Steeve Julien , St Fleur Sadrac , Calais Eric , Chèze Jérôme
Published: February 2023

On August 2021, 14th, a Mw 7.2 earthquake struck Haiti’s southern peninsula, eleven years after the devastating Mw 7 January 12, 2010 earthquake that occurred near Port au Prince. This large event, called the Nippes earthquake, has been recorded locally by the citizen network composed of low-cost raspberry shake stations. A precise analysis of the mainshock rupture from geodetic and seismic data revealed both left lateral strike slip and trust motion.Few days after the mainshock, a temporary network consisting of 12 broadband stations was deployed in the vicinity of the epicentral zone in order to better record the aftershock sequence. Data from August 20 to December 31, 2021, were used to determine a suitable 1D velocity model of the zone and relocate about 2500 aftershocks that highlight the activation of several structures.In this study, we focus our analysis on the region of Miragoâne situated between the ruptures of the 2021 and the 2010 earthquakes.  Before the Nippes earthquake, only a few events were detected there. Then, the Nippes earthquake triggered a burst of seismicity that lasted two months and stopped on November 2, 2021 and resumed in January 14 until March 10, 2022 with the occurrence on January 24th of two earthquakes in less than an hour of magnitude 5.3 and 5.1 respectively. We use the new 1D velocity model and the NonLinLoc using Source-Specific Station Term Corrections method (NLL-SSST) to relocate this seismic sequence. We find that the two larger earthquakes of magnitude slightly greater than 5 are closely located and confirm their reverse faulting mechanism using the waveform inversion method FMNEAR. The relocated seismicity is distributed from the surface to 20 km deep between the coast and the Enriquillo left-lateral strike-slip fault and along a plane which dips southward at ~50°, in agreement with the reverse faulting mechanism of the two larger magnitude > 5 earthquakes.
Solar potential mapping to address energy poverty in a data poor region: A case study in Plovdiv, Bulgaria
Authors: van Sark Wilfried , Koster Gabriela , Ricker Britta
Published: February 2023

Bulgaria suffers significantly from energy poverty. With the EU goal to reduce 55% of its emissions by 2030, careful considerations are needed in the decarbonization policies within the energy system to avoid redistributive consequences that affect vulnerable groups.
 
Decarbonizing the building sector through photovoltaic (PV) solar technology is a viable option and supported by EU directives. PV technology offers financial benefits for the public and reduces energy dependency from the grid. Mapping the solar potential of a building is needed to determine whether an investment in PV is viable. Solar potential mapping that incorporates socio-economic factors can inform policymakers on alleviating energy poverty.
 
In this paper, a solar potential mapping approach using ArcGIS Pro is developed that allows physical, technical, as well as socio-economic aspects, including social considerations. As a case study for Bulgaria, the city of Plovdiv was chosen.  Open datasets have been used. Energy affordability is used which can be determined on the basis of energy consumption and energy prices.
 
The results show that there is a high solar energy potential in Plovdiv, while the actual potential depends on which irradiance dataset is used. The potential is estimated to supply the entire city's electricity needs by 20-58%, which translates to providing electricity needs of about 90,000 to 135,000 inhabitants. The solar potential exceeds the building energy consumption needs of 200-300 kWh/m² in all the buildings in Plovdiv. The estimated potential savings after PV installation from utility bills is between €21-32 million annually. The socio-economic factors help place the potential values in perspective, thus visualizing the benefits of distributed PV systems. It strengthens the argument of developing policies including energy poverty indicators.
An analysis of city-wide changes of NO2 distribution in Munich, Germany
Authors: Wenig Mark , Ye Sheng , Zhang Hanlin , Chen Zeqing
Published: February 2023

The problem of elevated NO2 levels in cities has gained some attention in the public in recent years and has given rise to questions about the plausibility of banning diesel engines in cities, the meaning of exceedances of air quality limits and the effects of corona lock-downs on air quality to name a few. Urban air quality is typically monitored using a relatively small number of monitoring stations. Those in-situ measurements follow certain guidelines in terms of inlet height and location relative to streets, but the question remains how a limited number of point measurements can capture city-wide changes in the spatial distribution of NO2 concentrations. We utilize a combination of mobile and stationary measurements in Munich, Germany in order to estimate the fundamental drivers of urban air quality. We identified essential influencing factors like traffic volume, wind, boundary layer height, temperature, etc. and assessed for their impact on NO2 variability using a Generalized Additive Model (GAM) regression. Analyzing the impact factors separately allows us to allocate observed concentration peaks or drops, e.g. during lock down periods, to their key drivers.
A data-driven precipitation nowcasting framework using advanced deep learning model for video prediction and real-time learning approaches
Authors: Han Daehyeon , Choo Minki , Im Jungho
Published: February 2023

Quantitative precipitation nowcasting (QPN) is crucial for forecasting precipitation within the next several hours (generally up to 6) to prevent substantial socioeconomic damage. In general, ground radar data has been widely employed in QPN due to its high spatial-temporal resolution and more precise precipitation estimation than satellite. With the remarkable success of deep learning (DL), recent QPN studies have actively adopted DL using radar data. Although these studies yielded high skill scores in forecasting precipitation areas with a weak intensity (about 1 mm/h), they failed to effectively simulate the horizontal movement of precipitation areas and showed poor ability in forecasting precipitation with stronger intensities. In addition, despite the fact that the skill score is highly dependent on the characteristics of each precipitation event, there was a lack of evaluation over various precipitation cases. From the motivation that there can be room for improving QPN using the advanced DL model in video prediction, this study suggests the QPN model based on simple yet better video prediction (SimVP), which is a state-of-the-art DL model. We trained the SimVP model using radar data in South Korea from June to September (JJAS) for the period of 2019-2022, which includes the summer and early fall. In terms of the critical score index (CSI) with a lead time of 120 minutes (0.46, 0.23, and 0.09 for 1, 5, and 10 mm/h thresholds, respectively), the proposed model showed significant improvement over the existing DL models based on an evaluation from JJAS 2022. Considering different precipitation conditions, three case studies were conducted for heavy rainfall, typhoons, and fast-moving narrow convection events. The suggested model showed comparable or the highest CSI in 120 min with a 1 mm/h threshold in all cases, demonstrating robust performance (0.49, 0.69, and 0.29 for heavy rainfall, typhoon, and narrow convection, respectively). Qualitative evaluation of the proposed model also showed better results in terms of horizontal displacement movement and less underestimation than the other models. In addition, we further explored the possibility of real-time learning (RTL) with newly added radar data. By repeatedly optimizing DL model for currently facing precipitation events, RTL contributed to deep learning models predicting results more similar to actual radar patterns. It is expected that the proposed SimVP and RTL would serve as a new baseline for DL-based QPN due to their ease of implementation and enhanced performance. 
Benchmarking models with data: ecosystem carbon and nutrient budget along an elevation gradient in a subtropical forest ecosystem
Authors: Jiang Mingkai , Wang Zhikang , Wang Zhi
Published: February 2023

The ability to simulate vegetation dynamics and their feedback with nutrient cycling to affect ecosystem productivity underpins our prediction of the land carbon sink under climate change. Predictive models are now capable of simulating complex ecosystem processes, including the recent advancement in simulating vegetation dynamics and ecosystem phosphorus cycling, but there is a general lack of empirical evidence to form a systematic evaluation of the model predictions, especially how functional diversity affect ecosystem nutrient cycling and its consequence for productivity. Here, we developed a dataset based on 9 permanent plots (20 x 20 m) along an elevation gradient (300 – 1200m a.s.l.) in a subtropical forested mountain in eastern China. We measured vegetation growth, estimated forest structure and species composition, and compiled ecosystem-scale carbon (C), nitrogen (N) and phosphorus (P) budgets based on concentration, pool and flux data collected from dominant canopy trees, understorey herbaceous plants, and soil organic and inorganic components in these forested plots. Our aims are three-fold: 1) to understand how C, N and P are distributed along the plant-microbe-soil continuum; 2) to disentangle how different growth and nutrient use strategies of plant and soil microbes affect ecosystem productivity and regulate the rate nutrient cycling; and 3) to benchmark predictive models in simulating ecosystem vegetation dynamics and their interaction with C, N, and P cycle processes. Our research will contribute towards better understanding of the functional diversity and productivity relationship, and will contribute towards an improved predictive capacity to simulate vegetation dynamics and the land carbon sink under climate change.
Heat transfer in the Southern Baltic Sea
Authors: Rak Daniel , Dzierzbicka-Głowacka Lidia , Walczowski Waldemar , Bulczak Anna
Published: February 2023

The balance of energy supplied to the sea surface in the Baltic Sea proper is positive, which means that this region absorbs more energy than it releases to the atmosphere. Further transport of this energy in the form of heat is transported deep into the water column. It has been shown that differences between individual basins of the Baltic Proper appear along with the depth. The temperature signal, resulting from seasonal changes in the amount of solar energy supplied to the sea surface and the conditions of energy exchange between the sea and the atmosphere, propagates the fastest into the water column in the Gdańsk Deep, where it takes 37 days to a depth of 50 meters. In the Bornholm Basin, the speed of this signal is 71 days.
Maximum injection-induced earthquake magnitude in discrete fracture networks
Authors: Afshari Moein Mohammad Javad
Published: February 2023

Injection-induced earthquakes have been a major hurdle for developing Enhanced Geothermal System EGS technology. Hydraulic stimulation is often accompanied by injection-induced earthquakes that are manifestations of strain energy release over pre-existing discontinuities such as fractures and faults. Fluid injection perturbs the in-situ stress/strength and leads to seismic slip. Seismic risk and hazard assessment of injection into fractured rocks requires reliable estimates of the maximum magnitude. However, currently used maximum magnitudemodels do not properly address the site-specific geological conditions including the pre-existing fracture network.  More investigations are required to investigate the geological factors controlling the occurrence of induced earthquakes in fracture systems.In this contribution, we present the numerical models of dynamic and time-dependent simulation of induced seismicity based on discrete fracture network DFN approach. Here, the fluid-injection was simulated using a finite element model and the resulting deformation is translated into occurrence of seismic events. The transition between seismic and aseismic was captured by a static-dynamic friction model. The change of friction may cause frictional weakening on the neighboring elements, which is very similar to rupture nucleation and propagation. The total cumulative slip was modeled to capture the seismic deformation over fracture. The cumulative displacement of the neighboring segments was applied to compute the seismic moment and magnitude. The preliminary investigations indicated that the spatiotemporal evolution of induced seismicity is controlled by the connectivity of the system. In critically stressed conditions, the maximum induced earthquake magnitude is also largely influenced by the power-law exponent of fracture length distribution. The findings of this numerical study highlight the importance of precise fracture network characterization before injection experiments.
Wave-effect considering two-step wind speed retrieving algorithm for new GNSS-R satellite, TRITON
Authors: Zhang Lin , Chien Hwa , Yeh Wen-Hao
Published: February 2023

Global navigation satellite system reflectometry (GNSS-R) is designed to get the quasi-specular reflection of the GNSS signal over the Earth's surface. The reflected signal of GNSS-R recorded on a Delay-Doppler Map (DDM) may then be used to retrieve wind speed, ocean surface roughness, and latent heat flux over the open ocean and to retrieve soil moisture over the land. The L-band signal from GNSS is transmitted via forward (quasi-specular) scattering geometry, obeying the geometric optics (GO) limit of the Kirchhoff approximation (KA). One of the factors on DDM is bistatic radar cross section (BRCS) which represents sea surface roughness. The ocean surface slope and roughness spectrum sensed by GNSS-R response to the energy transferred to the ocean makes it possible for the wind speed to retrieve from the GNSS-R DDM. L-band (~1.5 GHz) microwave is less sensitive to the rain than higher frequency band signals such as Ku- band and C- band. There is a potential to use the L-band signal to retrieve wind speed over not only the fully-developed sea but over limited-fetch sea under more extreme weather systems, such as under tropical cyclones.In this study, we will present a wave-considering retrieving wind speed algorithm for the new GNSS-R satellite, TRITON. TRITON (Wind-Hunter Satellite) is designed and manufactured by Taiwan Space Agency (TASA) and will be launched in the first season of 2023.The wind speed retrieving algorithm contains self-built Level 1b (L1b) and Level 2 (L2) algorithms. The L1b algorithm starts from Level 1a output, power signal DDM in watts. We will introduce the procedure to calibrate the DDM to normalized bistatic radar cross section (NBRCS) in meters and compute the DDM observables (DDMA and LES) for the next level. The performance assessment of the self-developed Level 1 algorithm. Good agreements have been found compared to the CYGNSS results. The correlation coefficient among ~0.5 million DDMA_cygnss and DDMA_Triton points regression is 0.95. The root-mean-squared error is 4.99, with data ranging from 0 to 200, and the scattering index is 0.19.In the L2 algorithm, wind speed will be retrieved in two steps. In the first step, NBRCS will be used to compute the mean square slope (mss) with the help of the Fresnel reflection coefficient. In the second step, the relationship between wave age, mss, and wind speed developed based on the state-of-art microwave remote sensing study will be applied to retrieve wind speed. Uncertainty of the two-step algorithm will be assessed and compared with the results from the existing one-step geophysical model function algorithm to check the improvement. Results under the fully-developed sea and young-sea limited-fetch condition will be presented.Keywords: TRITON, wind speed retrieval, calibration, two-step algorithm, wave age, ocean surface roughness
If you get the stress data, you've always asked for
Authors: Reiter Karsten , Heidbach Oliver , Ziegler Moritz , Giger Silvio , Garrard Rodney , Desroches Jean
Published: February 2023

The upper Earth crust is increasingly used by mankind, to extract, transport, store or dispose materials, energy, or waste. Regardless of the objective, long term safety and stability is essential and thus, the contemporary stress state of the upper crust is one of the key variables. To estimate a continuous description of the 3‑D stress tensor, geomechanical numerical models are used. The most important parameters to set up such models are the knowledge of the underground structures, the distribution of rock properties as well as the stress data, on which the models are calibrated. In the model, the vertical stress results from the gravitational volume forces due to the density distribution and the horizontal stresses from the Poisson effect as well as appropriate lateral displacement boundary conditions. The latter are determined by finding a best-fit with respect to given stress magnitude data of the maximum and minimum horizontal stress SHmax and Shmin, respectively.A unique dataset of stress magnitude data has been recently acquired within the exploration phase for deep geological repository of radioactive waste in Switzerland. Nine cored boreholes in three potential siting areas have been drilled and besides a wide range of logging runs, and laboratory tests of rock properties, more than 120 Mini-Hydraulic Fracturing (MHF) and Sleeve Re-Opening (SR) tests were successfully performed in different stratigraphic units to estimate the magnitudes of Shmin and SHmaxHere, we present a 3‑D geomechanical-numerical model that shows both, the best-fit to the measured stress magnitudes as well as the range of stress magnitude variability in the volume of the different stratigraphic units. This variability results from MHF/SR measurements uncertainties and from the variation of rock properties within the lithologies. Furthermore, one has to assess how representative each MHF/SR measurement is for a larger rock volume. To represent the stress variability within the lithologies, many model simulations that cover the distribution of possible rock parameters were performed. The distribution is given by the cumulative density function (CDF) for the Youngs modulus and the Poisson number for each stratigraphic unit. Based on the range of model simulations we visualize the variation of the stress components along virtual well paths in analogy to the statistical variation. Such plots allow to quantify and visualize the potential variation of the present-day stress state within the stratigraphic column because of the petro-physical variability within the stratigraphic units. Furthermore, using the CDF, we can assign to each model simulation a probability that allows us also to estimate a probability distribution of the stress variability in the different units.
Easterlies/Westerlies convergence in the tropical Pacific triggering El Niño initiation?
Authors: Carniel Sandro , Eusebi Borzelli Gianluca
Published: February 2023

Climate change and climate variability play a relevant role on the occurrence of conflicts in several parts of the world, including the tropics, where events of flooding and droughts are dictated by El Niño Southern Oscillation (ENSO). In order to better analyze possible relations between conflicts hot-spots and ENSO impacts on society and security, a better understanding of the dynamics of the latter is needed. ENSO is the result of an ocean-atmosphere feedback, which produces an irregular oscillation between a warm (El Niño) and a cold (La Niña) phase, peaking in boreal winter and recurring every 2-5 years. During La Niña phase, intensified trade winds accumulate warm water in to the west of the Pacific, leading to droughts in the northern US and catastrophic floods in regions such as northern Australia. During El Niño warm phase, westerly winds advect warm waters eastward towards the coasts of America, generating dry conditions in northern US and Canada, and wetter periods in the US Gulf Coast areas. Most of the studies on ENSO focused on the coupling between changes in the depth of the main thermocline, heat content in the surface layer of the water column and oceanic feedback on the zonal wind pattern. According to these works, the subsurface memory of the ocean (i.e. the heat stored in the surface layer), depends on the depth of the thermocline and the zonal shape of the isothermal surfaces is sustained by the dynamical balance between the zonal pressure gradient and the trade winds. This process systematically transfers heat westward and “charges” the western Pacific, which is then “discharged” through the action of eastward propagating internal Kelvin Waves (KW). While westerly wind events are known to play an important role in the generation of KW associated with El Niño, much less is known on the role of easterly winds. Here we show that the encountering between Westerlies and Easterlies determines the convergence, providing the initial forcing exciting internal, downwelling Rossby and Kelvin waves. Only KW formed east of 175oE  reach the eastern Pacific boundary and determine an El Niño events, that become the more intense the more the waves are formed eastward, indicating a “zonal position” triggering of El Niño. It is shown here that the zonal shifts of the Easterlies/Westerlies convergence region displaces zonally in phase with region of the deep atmospheric convection and with the Southern Oscillation Index, indicating that changes in the large scale pressure system, the zonal position of westerly wind events, the easterly wind variability, the position of the deep atmospheric convection and El Niño are all intimately related features of the whole tropical Pacific climate system.Funding from the STO Office of Chief Scientist 907EUR30 is gratefully acknowledged.
Decadal predictability of European temperature extremes.
Authors: Tsartsali Eirini , Athanasiadis Panos , Tibaldi Stefano , Gualdi Silvio
Published: February 2023

Accurate predictions of climate variations at the decadal timescale are of great interest for decision-making, planning and adaptation strategies for different socio-economic sectors. Notably, decadal predictions have rapidly evolved during the last 15 years and are now produced operationally worldwide. The majority of the studies assessing the skill of decadal prediction systems focus on time-mean anomalies of standard meteorological variables, such as annual mean near-surface air temperature and precipitation. However, the predictability of extreme events frequency may differ substantially from the predictability of multi-year annual or seasonal means. Predicting the frequency of extreme events at different timescales is of major importance, since they are associated with severe impacts on various natural and human systems. In the current study we evaluate the capability of state-of-the-art decadal prediction systems to predict the frequency of temperature extremes in Europe. More specifically, we assess the skill of a multi-model ensemble from the Decadal Climate Prediction Project (DCPP, 163 ensemble members from 12 models in total) to forecast the number of days belonging to heatwaves episodes during summer (June–August). We find statistically significant predictive skill over Europe, except for the United Kingdom and a large part of the Scandinavian Peninsula, most of which is associated with the long-term warming trend. We are progressing with the evaluation of other statistical aspects of extreme events, including warm and cold episodes during winter, and we are also investigating whether there is predictive skill beyond that stemming from the external forcing.  
A universal decay function based meteorologically-driven and calibration-free runoff generation module
Authors: Istalkar Prashant , Biswal Basudev
Published: February 2023

An accurate estimate of streamflow has been a challenging task due to the complex and interconnected hydrological processes. A simple, robust and calibration-free runoff generation module is desirable in several water resource management applications. But spatial heterogeneity of, but not limited to, topography, soil and land cover makes it challenging to develop desirable runoff generation module. To address this, several runoff generations theories that apply laws of physics at the grid-scale were proposed and tested.  However, these theories have not shown a significant difference in performance on considering catchment as spatially distributed and a single unit(lumped). A typical runoff generation module follows saturation excess or infiltration excess mechanism for runoff generation. The root zone storage capacity (Smax), which controls the dynamics of water storage and partitioning of available water into different fluxes, is an important free-parameter in the saturation excess mechanism. The value of Smax needs to be estimated using observed streamflow time series. However, recent studies demonstrate that the Smax is controlled by local climate and land cover. So, in the current study, we hypothesized that runoff generation is solely governed by climate input and the amount can be estimated without explicit consideration of Smax. We tested the hypothesis using Dynamic Budyko (DB) framework, which simulates the runoff at a daily time scale using ‘instantaneous dryness index (Φ)’. We proposed a universal decay function to predict Φ using rainfall and potential evapotranspiration. The performance of proposed runoff generation module is compared with HBV and GR4J runoff generation modules for 416 MOPEX study basins. The proposed calibration free runoff generation module shows very similar performance to that of calibrated HBV and GR4J with median NSE as 0.68,0.7 and 0.68, respectively. The proposed framework can be coupled with any routing module to estimate the streamflow at basin outlet. The introduction of proposed framework address several long-term challenges in rainfall-runoff modeling. Our results suggest that more efforts should be considered in developing rainfall-runoff modeling frameworks that exploit information available in meteorological input to address streamflow dynamics.
Non-Additivity of the Midlatitude Circulation Response to Regional Arctic Temperature Anomalies: The Role of the Stratosphere
Authors: De Bithi , Wu Yutian , Polvani Lorenzo , Elsaesser Gregory
Published: February 2023

Previous studies have documented the impact of the Arctic sea ice loss and associated warming on the midlatitude weather and climate, especially the influence of sea ice retreat over the Barents-Kara Sea on the North Atlantic and Europe regions. However, less attention has been given to other geographical locations over the Arctic, and to the linear additivity of the circulation response to regional Arctic sea ice loss and temperature anomalies. Using a simplified dry dynamical core model, we demonstrate that responses to regional Arctic temperature anomalies over the Barents-Kara Sea, Baffin Bay-Davis Strait-Labrador Sea, and East Siberia-Chukchi Sea, separately, cause similar equatorward shift of the tropospheric jet, but different stratospheric polar vortex responses. Furthermore, responses to regional Arctic temperature anomalies are not linearly additive, and the residual resembles a positive Northern Annular Mode-like structure. Additional targeted experiments highlight the stratospheric influence in the non-additivity of the midlatitude tropospheric response.
The Central Afar region as an analogue for the development of oceanic plateaus?
Authors: Rime Valentin , Foubert Anneleen , Ruch Joël , Kidane Tesfaye
Published: February 2023

Oceanic plateaus are traditionally considered as oceanic crust thickened by magmatic processes. In the last decades, however, continental material significantly older than the surrounding oceanic crust has been recovered from drillings on oceanic plateaus (e.g. Rio Grande Rise, Mauritius and Mascarene Plateau, Elan Bank), leading to numerous questions about the origin of these structures.The Central Afar region is part of the Afro-Arabian Rift System. It witnessed the eruption of the Ethiopian Flood Basalts approx. 30 My ago followed by rifting. Mapping, plate kinematic modelling and geophysical data show that, despite important extension, the area features relatively thick crust. This crust is characterized by important magmatic underplating, intrusions, and volcanic material with isolated continental fragments. Therefore, it might represent an analogue for the development of oceanic plateaus. Numerous rift jumps and magma-compensated thinning linked to the presence of the Afar hotspot can explain the structure of the Central Afar. Unlike Central Afar, the Danakil Depression in northern Afar shows more classical structures and will probably develop into a magma-rich margin. The Afar depression thus constitute a unique example of the early development of different types of passive margins and oceanic plateaus.
Witnessing a Forbush Decrease with a Microscintillator Ionisation Detector over the Atlantic Ocean
Authors: Tabbett Justin , Aplin Karen , Barbosa Susana
Published: February 2023

A novel ionisation detector, previously deployed on meteorological radiosonde flights, has demonstrated responsivity to X-rays and gamma radiation, and additionally, is thought to be sensitive to ionising radiation from cosmic rays. The PiN detector, composed of a 1x1x0.8 cm3 CsI(Tl) microscintillator coupled to a PiN photodiode, was deployed on the NRP Sagres sailing vessel on a cruise in the Atlantic between Portugal and the Azores in 2021. The instrument can determine both the count rate and energy of incoming ionising radiation particles.The instrument was operational during the voyage in November 2021 when a coronal mass ejection event induced a sudden decrease in the observed cosmic ray intensity, known as a Forbush decrease. We present data recorded by the ionisation detector during this period, to characterise the instrument’s ability to detect cosmic ray events, and we compare the performance with neutron monitoring stations Oulu in Finland, and Dourbes in Belgium. As the PiN detector provides spectral and count rate data, it is possible to group events by their energy, and investigate the count rates of specific energy regimes. This approach is useful as many sources – including high and low energy ionising radiation from cosmic rays – contribute to the background energy spectrum. As a result, more meaningful comparisons and relationships can be established with the neutron monitoring stations.
Evaluation of the slopes stability in the lava field of the 2021 Tajogaite eruption (La Palma, Canary Islands) in order to recover the territory for the development of new infrastructures
Authors: Rodríguez-Losada Jose Antonio , Hernández-Gutiérrez Luis E. , Miranda-Hardisson Ana , González de Vallejo Luis I. , Cervigón-Tomico Germán , de los Ríos Díaz Héctor , de Villepreux Ernaud , Álvarez-Hernández Aarón , Afonso-Falcón David
Published: February 2023

The Tajogaite volcanic eruption took place at the west side of La Palma (Canary Archipelago) from september 19 to december 13 of 2021. Around 200 million cubic meters of lava emitted by the volcano ended up burying an area of 12.2 km2, destroying around 1,700 buildings and causing the displacement of roughly 7,000 people. In order to promote the recovery of the affected territory, the regional authorities commissioned to the Volcanological Institute of the Canary Islands (INVOLCAN), a report consisting on a Evaluation of the slopes stability in the new lava field and nearby areas which is summarized in this work. The results were applied to a three selected areas called reconstruction sectors with the following names: 1) La Laguna, 2) La Asomada and 3) Las Norias-La Majada. These sectors were divided into 250 x 250 m grids on which a susceptibility estimation was carried out.The field reconnaissance and aerial photography, allowed the identification of a series of surfaces and slopes within those sectors whose stability was valued based on the Slope Susceptibility Index in Volcanic Terrains (ISTV). The stability was scaled into four main categories according to the ISTV value: very high (ISTV ≥80); high (ISTV 60-79); moderate (ISTV 35-59) and low (ISTV <35).In La Laguna sector, of four study points, two of them were classified as moderate, one as low and another one as high. In La Asomada sector, only one study point could have been evaluated as high and finally, in Las Norias-La Majada sector, of twelve study points, eight of them were classified as moderate, two as low, one as high and another one as very high, being the moderate ISTV the most dominant in this sector.
International education and research during the pandemic: 31st European Dendroecological Fieldweek 2021 in Val Mustair, Switzerland
Authors: Kaczka Ryszard , Treydte Kerstin , Martínez-Sancho Elisabet , Dorado-Liñán Isabel , Verstege Anne , Piermattei Alma , Crivellaro Alan ,   Participants of the 31st European Dendroecological Fieldweek
Published: February 2023

The European Dendroecological Fieldweek (EDF) provides an intensive learning experience in tree-ring research for anyone approaching or working in dendrochronology. Here we present an overview of scientific activities of the 31st EDF, held in Val Müstair, Switzerland, in summer 2021. Despite the COVID-19 pandemic, the EDF gathered 20 participants and 10 instructors (7 dendrochronologists and 3 local experts) from 10 European countries and provided valuable outcomes for the local stakeholders such as Biosfera, the forest service and the private-public of Val Müstair.During the eight days of the EDF, six groups developed different tree-ring projects, carefully designed with respect to the loal environmental setting. The dendroarchaeology group dated two buildings, an abandonned stable and a house in Val Müstair, providing private owners with accurate construction dates. The dendroclimatology group explored the potential of a relict Scots pine forest growing at ~2000 m asl for climate reconstruction, and created a chronology from 1648 to 2020 CE. The wood anatomy group found that the larger vessel sizes and and higher radial growth rates of two alpine shrub species at moist compared to dry sites, while tree ages were similar at both sites. The Blue Intensity group identified a robust climate signal in the BI chronology of high-elevation Norway spruce trees, which was significantly stronger than in the tree-ring width chronology. One dendroecology group found that growth of local larch trees recorded outbreaks of the grey larch budmoth between 1880 and 1980, a stop of outbreaks after and its return in 2018. A second dendroecology group investigated larch trees along an abandoned irrigation channel and could not detect a significant effect of the irrigation stop on growth.The EDFs continuously provide an essential service to the dendrochronological community, and this even during challenging times. The 31st EDF was again an educational, scientific and multi-cultural experience in a unique environmental setting. It resulted in highly interesting and valuable scientific outreach and opened up new avenues for future tree-ring research in Val Mustair. 
Causal Drivers Behind Enhanced Rainfall Activity OverNorthern Indian
Authors: Aviles Podgurski Luisa E. , Di Capua Giorgia , Donner Reik V.
Published: February 2023

The Western (WHF) and Eastern Himalayan foothills (EHF) are two densely populated regions that experience extreme precipitation events during the Indian summer monsoon (ISM) season lasting typically from June to September [1, 2]. Therefore, a better understanding of the processes controlling ISM intraseasonal variability is of great relevance.In our present work we identify and quantify causal relationships at short lead-times (three to nine days) between characteristic remote and local climate patterns and the precipitation over the WHF and EHF. More specifically we apply the so-called response-guided causal precursor detection (RGCPD) scheme that builds on the Peter and Clark momentary conditional dependence (PCMCI) algorithm [3]. The employed method is based on concepts of information theory and statistical mechanics, and allows to identify strongly interdependent climate patterns associated with the ISM and to distinguish between spurious and truly causal links. Finally, causal effect networks (CENs) visually summarise the identified causal links between different variables, indicating the directionality, time lag and magnitude of the causal effect.Our analysis reveals that WHF rainfall variability is influenced by mid-latitude teleconnections such as the circumglobal teleconnection index and seems to be driven by similar precursors and time scales as the precipitation over central India [4]. In contrast, CENs indicate that the EHF rainfall is characterised by faster dynamics compared to the WHF and whilst it is also driven by mid-latitude teleconnections, a different set of atmospheric processes appears to play a major role in its variability. Specifically, a unique and strong causal connection to the tropical western Pacific is revealed, manifesting itself in the geopotential height at 500 hPa and the mean sea-level pressure. A thorough analysis of this signal indicates a Gill-type response to a heat sink over the equatorial Pacific, that may be associated with the Madden-Julian oscillation (MJO) and suggests a link between suppressed MJO phases and enhanced rainfall activity over the EHF region. Thus, our analysis hints to a connection between break spells of the ISM, where large parts of the Indian landmass experience reduced precipitation activity, and enhanced rainfall activity over the EHF region.References[1] Vellore, R., et al., On the anomalous precipitation enhancement over the Himalayan foothills during monsoon breaks, Clim. Dynam. 43, 2009-2031 (2014).[2] Vellore, R., et al., Monsoon - extratropical circulation interactions in Himalayan extreme rainfall, Clim. Dynam. 46, 3517-3564 (2016).[3] Runge, J., Causal network reconstruction from time series: From theoretical assumptions to practical estimation, Chaos 28, 075310 (2018).[4] Di Capua, G., et al., Tropical and mid-latitude teleconnections interacting with the Indian summer monsoon rainfall: a theory-guided causal effect network approach, Earth Syst. Dyn., 11, 17-34 (2020).
The effect of intrusive activity on the Krafla geothermal system, NE-Iceland: The Krafla fires 1975-84
Authors: Fehrentz Patricia , Guðmundsson Magnús Tumi , Reynolds Hannah Iona , Mortensen Anette Kærgaard
Published: February 2023

Young igneous geothermal systems derive their energy from magma in their roots.  Some of them have been utilized for electricity production and other uses of geothermal energy.  Iceland has several young igneous geothermal systems and has been pioneering the harnessing of geothermal energy derived from such systems.  Iceland is ideally located for the occurrence of young igneous systems, being underlain by a mantle plume and sitting on the Mid-Atlantic Ridge. Although the overall structure and temperature distribution of young igneous systems are well known in some areas, the nature of how they are recharged by magma has been poorly constrained.  The Krafla high-temperature geothermal area in North-East of Iceland is one of the best-known such systems.  Between 1975-1984 the so-called "Krafla Fires" took place, associated with the widening of the Krafla fissure swarm by several meters, during episodes of volcanic activity consisting of 20 extrusive and intrusive events.  The effects of this intrusive and extrusive activity on the geothermal system are a subject of ongoing research. The intrusions, injected into the geothermal system, are estimated to have had a volume of 0.12-0.19 km3 and added 4-8 x 1017 J of heat to the system through the solidification and cooling of these intrusions. This heat is released and transferred within and out of the system as cooling and solidification occur.  After each rifting event, some of which were accompanied with fissure eruptions on the surface, this additional heat input was visible on the surface of the geothermal system as intensive steaming.  This was especially prominent in fissures and fractures along the main axis of rifting.  The intrusive activity may have increased the temperature in parts of the system by several tens of degrees. 
European windstorm risk at the regional scale under recent and future climate conditions
Authors: Alifdini Inovasita , Moemken Julia , Pinto Joaquim G.
Published: February 2023

European windstorms are among the natural hazards with the highest economic losses. We investigate the impact of European windstorms under recent and future climate conditions at high spatial resolution. With this aim, we use hourly surface wind data at 30 km resolution from ERA5 reanalysis for 1959-2021, and 3-hourly surface wind data at 12.5 km resolution from 60 different global-to-regional climate model (GCM-RCM) chains from EURO-CORDEX (EUR-11). The windstorm activity is compared in 30-year periods from the historical events (1976-2005) to the future events (under RCP8.5 scenario) at global warming levels (GWL) of +2°C and +3°C.  We apply different indices (meteorological index and loss index) to quantify the severity of windstorms and to estimate the corresponding impacts. For the historical period, storm Wiebke in 1990 (storm names as used by the German Weather Service DWD) caused the highest loss for Central Europe, followed by storm Lothar in 1999. The United Kingdom and Germany are countries in Central Europe that have the highest loss index (more vulnerable to the European windstorms). The results from the EURO-CORDEX ensemble show only small changes in windstorm activity between the historical period and the different GWLs, but display decadal variability.
The origin of early Archean barite deposits on the Kaapvaal and Pilbara cratons
Authors: Roerdink Desiree , Mason Paul , van Zuilen Mark , Wilmeth Dylan
Published: February 2023

Sulfate minerals are rare in the geological record prior to the oxygenation of the Earth’s atmosphere circa 2.4 billion years ago (Ga). An exception to this are a few isolated occurrences of early Archean (3.6-3.2 Ga) barite (BaSO4), hosted in volcano-sedimentary rocks in South Africa, India and Western Australia. The origin of these barite deposits is controversial, despite having been studied over decades. Here, we combine field observations and geochemical data from a multi-year investigation into barite occurrences on the Kaapvaal and Pilbara cratons to derive a holistic model for the formation of early Archean barite. Studied deposits include the 3.52 Ga Londozi deposit in Eswatini and the 3.49 Ga North Pole deposit in Western Australia that are hosted in volcanic rocks, and the 3.26-3.23 Ga Barite Valley deposit in South Africa and possibly time-equivalent but little-known Cooke Bluff deposit in Western Australia that are found in sedimentary successions. Our field observations indicate that barite is closely associated with chert on both the Kaapvaal and the Pilbara cratons, although the scale of barite mineralization is much larger in the Pilbara and cross-cutting barite veins are only observed at North Pole and Cooke Bluff. These findings suggest that the fluids from which the chert precipitated are the same as the fluids from which the barite formed, and geochemical data support an origin for these barium-rich fluids that is related to low-temperature hydrothermal circulation of seawater. Barite precipitation could have been triggered by silica removal from these fluids. The ubiquity of chert in the early rock record suggests that these settings may have been common in the early Archean and that barite formation was therefore limited by sulfate abundance, and could only occur in settings where hydrothermal circulation and local sulfate enrichment occurred together.