bluuebunny/crossref_metadata_2025 huggingface dataset:
Applicability of optimal stomatal conductance models during a simulated heat wave in grapevine
Authors: Asensio Dolores , Hammerle Albin , Niedrist Georg , Shtai Walaa , Kadison Amy , Schwarz Michaela , Raifer Barbara , Andreotti Carlo , Zanotelli Damiano , Haas Florian , Tagliavini Massimo , Wohlfahrt Georg
Published: March 2024

Optimization models of stomatal conductance (gs) provide a conceptual framework to understand stomatal responses to environmental changes in terms of tradeoffs between the benefits and costs of stomatal opening. Theoretically, stomata maximize the benefits (carbon gain, A) and minimize the costs (water loss through transpiration, E). However, during heat waves, there can be conflicts between the need to maintain a high E to control leaf temperature via evaporative cooling and avoid heat damage, and the decrease in gs in response to increased VPD and reduced soil water availability. Under these conditions, the balance between the gains and the associated costs remains unclear. We measured leaf gas exchange (A, E and gs) in potted grapevines, cv Sauvignon Blanc, before, during and after a simulated six-day heat wave (Tmax = 40 °C), in the morning (10 to 12) and the afternoon (15 to 17), using heated well-watered (HW), heated drought-stressed (HD), non-heated well-watered (CW) and non-heated dry (CD) vines. We also measured plant transpiration (Elys) and leaf temperature (Tleaf) continuously during the heat wave using lysimeters and infrared cameras. We test the hypothesis that under combined stress, in addition to the stomatal limitation to A, there is an additional non-stomatal cost for A caused by the heat damage in the photosystem. We explore whether this potential additional cost is captured by two gs optimization models that include soil-to-leaf hydraulic conductance (model 2) or not (model 1). We also hypothesize that gs in HW vines may not follow the optimal predictions because these models do not include stress-related risks such as heat damage due to higher-than-optimal Tleaf resulting from stomal closure and reduced E. There were no significant differences in gs in HD and CD vines, during the morning or the afternoon measurements. Consequently, there were no differences in measured E and A between HD and CD vines during the peak of the heat wave. This was probably due to the stronger effect of water stress (soil water potential from -400 to -800 kPa) than high VDP (5 kPa) on gs during the peak of the heat wave. Under well-watered conditions, measured gs, E and A in the morning were much higher in HW than in CW vines and the values decreased from the morning to the afternoon. Preliminary results suggest that optimal models including dynamic responses to soil water potential can correctly integrate plant responses to heat and drought stress. The incorporation of stress-related risks (such as heat damage to the photosystem) into these models will be discussed.
Long-term evaluation of turbulence parameterisations using Doppler lidar 
Authors: Harvey Natalie , Dacre Helen , Walden Chris , Hanley Kirsty , Lean Humphrey
Published: March 2024

Turbulence in the atmospheric boundary layer governs the exchange of heat, moisture, and other atmospheric constituents between the surface and the free troposphere. This exchange plays a pivotal role in initiating moist convection which influences the timing and location of convective rainfall. As operational weather forecasts increasingly move towards km and sub-km grid spacing, resolving larger boundary layer turbulent structures becomes possible, necessitating adjustments to turbulence parameterisation schemes. The UMBRELLA (UM Boundary-layer REpresentation with Land-Atmosphere Interactions) project aims to evaluate the performance of the UM (Met Office Unified Model) boundary layer turbulent parameterisation schemes for different grid spacings, ranging from 100m to 10km. Here, analysis of long-term Doppler lidar and sonic anemometer observations at Chilbolton, Hampshire is presented, with particular focus on long-term statistics on boundary layer vertical velocity, vertical velocity variance and skewness, along with sensible heat flux. These quantities are combined with the presence of cloud and aerosol height to classify the boundary-layer into different regimes and used to evaluate the UM turbulence parameterisations. The Doppler lidar statistics are compared to an 18-member ensemble UM run at 300m grid spacing for the 3-month WesCon field campaign which took place in the UK during summer 2023. While the primary focus of this project is on the UK and the UM, the developed methodology could be applied to other locations worldwide.
Impact of Hunga Tonga-Hunga Ha’apai water vapour on polar vortex dehydration and ozone depletion: Antarctic 2023 and Arctic 2024
Authors: Zhou Xin , Heddell Saffron , Dhomse Sandip , Feng Wuhu , Mann Graham , Pumphrey Hugh , Kerridge Brian , Latter Barry , Siddans Richard , Ventress Lucy , Querel Richard , Smale Penny , Asher Elizabeth , Hall Emrys , Bekki Slimane , Chipperfield Martyn
Published: March 2024

The January 2022 eruption of Hunga Tonga-Hunga Ha’apai (HTHH) injected a huge amount (~150 Tg) of water vapour (H2O) into the stratosphere, along with small amount of sulfur dioxide (SO2). Following slow transport in the meridional Brewer-Dobson circulation, the additional H2O is now distributed throughout the stratosphere. Here we use an off-line 3-D chemical transport model (CTM) to study the residence time of this excess H2O and its impact on polar ozone depletion. The model results are compared to satellite data from the Microwave Limb Sounder (MLS), the Ozone Monitoring Instrument (OMI), and Infrared Atmospheric Sounding Interferometer (IASI), and to balloon-borne measurements from Scott Base (77.8oS).Simulations with the TOMCAT/SLIMCAT CTM successfully reproduce the spread of the injected H2O through late 2023 (at time of writing) as observed by MLS. Dehydration in the 2023 Antarctic polar vortex caused the first substantial (~20 Tg) removal of HTHH H2O from the stratosphere. The CTM indicates that this process will dominate removal of HTHH H2O for the coming years, giving an overall e-folding timescale of 4 years; around 25 Tg of the injected H2O is predicted to still remain in the stratosphere by 2030.We have diagnosed the additional H2O chemical impacts on stratospheric ozone throughout the simulation, with a focus on the 2023 Antarctic ozone hole. Following relatively low Antarctic column ozone in midwinter 2023 due to transport effects, additional springtime depletion due to H2O-related chemistry was small and maximised at the vortex edge (10 DU in column). Effective dehydration in the core of the vortex limited the impact of the additional H2O.We will also discuss the HTHH-H2O impacts on ozone depletion in the forthcoming 2024 springtime Arctic vortex. This will be the first Arctic winter with likely substantial HTHH enhancement of lower stratospheric H2O. As dehydration is rare in the Arctic, there is the possibility of differing impacts compared to the Antarctic through the persistence of the enhanced H2O at the pole.
Understanding the effects of spacecraft trajectories through solar coronal mass ejection flux ropes using 3DCOREweb
Authors: Rüdisser Hannah Theresa , Weiss Andreas J. , Möstl Christian , Amerstorfer Ute V. , Davies Emma E. , Weiler Eva
Published: March 2024

A special observational signature in ICMEs that has puzzled researchers for a long time are so-called ”back regions” or ”magnetic-cloud-like (MCL)” parts of ICMEs which follow after the main flux rope rotation has passed the observer. These regions, occurring after the main flux rope rotation, display a peculiar behaviour where the magnetic field remains elevated with minimal rotation. Two proposed explanations involve magnetic reconnection during CME propagation or a purely geometric effect as the observer traverses the flux rope . We investigate in detail whether MCLs can be explained by an effect of the trajectory of an observer through a 3D expanding magnetic flux rope, without invoking magnetic reconnection as an explanation for those signatures. To this end, we employ the 3D coronal rope ejection (3DCORE) model, which has proven its ability to fit in situ magnetic fields of CME flux ropes. The model assumes an empirically motivated torus-like flux rope structure that expands self-similarly within the heliosphere, is influenced by a simplified interaction with the solar wind environment, and carries along an embedded analytical magnetic field. Developed for fitting, generating synthetic signatures, comparing models to observations, and analysing results, 3DCOREweb accelerates the determination of physical parameters, fostering research on the global magnetic structure of CMEs. Additionally, the interface aids in advancing our understanding of magnetic flux rope signatures arising from diverse 3D trajectories through CMEs.
Advantages of DTW windowing function in automated correlation of stratigraphic time series
Authors: Samant Rohit , Giorgino Toni , Jarochowska Emilia , De Vleeschouwer David
Published: March 2024

The Dynamical Time Warping (DTW) technique has been originally developed for speech recognition in the late 1960s and early 1970s and has more recently been applied in geoscientific studies. One of the key objectives of dtw is to stretch or compress two complementary series locally in order for one series to resemble the other as much as possible. In our project, we aim to correlate industrial and scientific downhole wireline logs from offshore Australia, with the ultimate goal to obtain a regional paleoclimate reconstruction at high spatial resolution (“All around Australia”). Here, we propose a novel way to constrain the alignment of two sedimentary sequences based on a-priori stratigraphic information. Therewith, we provide a means to make dtw calculations less computationally expensive, while still evaluating all possible stratigraphic correlations, even for long time-series.The “All around Australia” project focuses on the automated correlation of thousands of scientific and industrial time-series. Hence, it is important to speed up the calculations and reduce the computational costs. The global constraint on dtw, also known as the window function, speeds up the calculations by limiting the 2-dimensional space of possible alignments between two time-series. As a case study, IODP Site U1463 (Northwest Shelf of Australia) serves as the reference to which two industrial sites (Finucane-1 and Angel-2) are correlated. Biostratigraphic datums of Site U1463 have few meters of depth uncertainty. Their corresponding depths at the industrial sites are manually determined, albeit with a depth uncertainty that is one order of magnitude higher (so-called “slack”).  These manually determined correlation points are then utilized to create custom-made windows, reflecting a priori knowledge of the large-scale stratigraphy of the studied basin. In this case, the comparison of the computational time and the goodness-of-fit for ‘no-window’ and ‘windowed’ dtw calculations reveals that the quality of the correlation improves and computational time is reduced by 15-20%. Hence, the novel window function is primarily useful for stratigraphers to guide the dtw algorithm in creating warping paths that are stratigraphically more plausible. 
Optimizing irrigation practices for sustainable olive production in semi-arid areas: A comparative analysis of the efficiency of Subsurface and Surface drip irrigation systems 
Authors: Ourrai Sara , Aithssaine Bouchra , Amazirh Abdelhakim , Er-raki Salah , Bouchaou Lhoussaine , Jacob Frederic , Kharrou Mohamed Hakim , Chehbouni Abdelghani
Published: March 2024

Abstract : Irrigated olive trees constitute the main arboricultural component of orchards in semi-arid regions, and the optimization of irrigation practices is crucial to sustain the production, increase agricultural water productivity and reallocate water savings to other higher-value uses. Numerous technical strategies have been implemented in the last two decades, to promote water conservation in irrigated agriculture, namely the adoption of subsurface drip irrigation system. This study delves into a comprehensive comparative analysis between subsurface (SDI) and surface (DI) drip irrigation systems over an olive orchard, with an emphasis on the evolution of evaporative fraction (EF) and the ratio of transpiration (T) to evapotranspiration (ET), soil moisture distribution patterns, as well as water use efficiency and water productivity. The experiment was carried out over two irrigated olive plots located in the Tensift basin (Morocco), from May to October 2022. Each plot is subjected to a specific irrigation pattern, and equipped with an Eddy-Covariance system to quantify the energy balance components, along with Time-Domain-Reflectometry (TDR) sensors installed at various depths, to monitor the soil water content. Besides, the partitioning of ET into T and evaporation (E) over the two irrigation systems was performed using the Conditional Eddy-Covariance (CEC) scheme and validated using sap flow measurements collected over SDI plot during April 2023. The ET of the DI system was higher than that of the SDI one, with diurnal ET values ranging between 0.58-3.02 (mm/day) and 0.48-2.74 (mm/day) for DI and SDI systems, respectively. Our findings suggest that although a smaller irrigation water amount was applied in SDI (194 mm) compared to DI (320 mm), crop yield revealed no significant differences. This thorough assessment intends to add substantial knowledge to the lasting debate about sustainable irrigation practices over olive orchards and assist policymakers in making informed decisions to enhance water use efficiency while sustaining overall agricultural production.Keywords: subsurface and surface drip irrigation; evapotranspiration; water productivity; water use efficiency; olive trees; semi-arid areas.
Transition from Unstable Slip to Rate-Dependent Creep Controlled by High Fluid Pressure
Authors: Zhang Lei , He Changrong , Barbot Sylvain
Published: March 2024

To investigate the frictional behavior of basalt under hydrothermal conditions, we apply sliding experiments using basalt gouge under the temperature of 100-600ºC, effective normal stress of 150MPa, and fluid pressure of 30MPa and 100MPa, respectively. Experiment results under 30MPa pore pressure show that basalt exhibits velocity-strengthening behavior at 100-200ºC and changes to velocity-weakening behavior at 400-600ºC; meanwhile, at 400ºC, velocity dependence of basalt evolves with slip from initial velocity weakening to velocity-strengthening. Results under 100MPa fluid pressure show a similar transition of velocity dependence at 300ºC; however, at higher temperatures of 400-600ºC, velocity strengthening behavior occurs, accompanied by strong slip weakening behavior at the slowest loading rate (0.04μm/s). During the velocity step, the experiment exhibits a rate-dependent creep without transient evolution with slip. Microstructure observation reveals significant differences between samples sheared under 30MPa and 100MPa fluid pressure. At higher fluid pressure and temperatures of 400-600ºC, the porosity of the basalt gouge layer is significantly reduced, and deformation is characterized by pervasive shear with no apparent localization. Such results suggest that the healing process/plastic deformation is activated at higher fluid pressure, leading to slip stability transition and slip-weakening of frictional strength.
Image of the crust and upper mantle tectonic structure and associated mineral systems of the central Norwegian Caledonides from 3D inverse geoelectrical models
Authors: Kovacikova Svetlana , Hill Graham , Gradmann Sofie , Klanica Radek , Karcioglu Gokhan , Vozár Jan , Kamm Jochen , Mishra Pankaj , Smirnov Maxim , Rydman Oskar
Published: March 2024

The current effort to move to more renewable energy sources and away from a petroleum based energy economy, ‘Net Zero’, places a renewed need for improving identification and characterization of mineral deposits in order to provide the materials required. Recent work, has demonstrated the benefit of larger aperture investigations of mineral systems for both determining the processes responsible for their emplacement as well as identifying indicative geophysical signatures associated with metal endowment. The central Norwegian Caledonides historically represent a zone of large mineral endowment, though; the large-scale structural history and process that formed the mineralization remain enigmatic. Formation and concentration of metals into economic mineral deposits requires a combination of processes operating at different scales. With the near surface mineral deposit being a small component of the larger mineral system which encompasses deep fluid sources and metals, an energy source for driving circulation pathways for the migration of enriched fluids, a depositional mechanism responsible for the formation of the deposit and a fluid outflow. The Norwegian mineral deposits lie within the allochthonous nappes, detached from the original Precambrian Svecokarelian and Sveconorwegian basement and having undergone tens to hundreds of km of lateral transport. Regional scale geophysical modelling of petrophysical properties has the ability to characterize and identify the structure and process occurring throughout the entire mineral system  and determine indicative structures at mid-lower crustal depths indicative of economically viable near surface regions of metal endowment (i.e. the near surface mineral deposit). To determine the processes associated with formation of the Norwegian Caledonides and its associated mineral deposits a dense network of ~300 broadband magnetotelluric soundings covering the period range 10-3-103s have been collected over two field campaigns in 2022 and 2023 in the Trondelag area of central Norway. Phase tensor analysis indicates that the data set is 3D at all scales – we have modelled the MT data using a 3D approach (GoFEM) capable of incorporating the rugged topography of the survey area. Preliminary modeling results reveal lithospheric-scale structural controls associated with known near surface mineral deposits and processes related to the lateral transport from the underlying lower crustal source regions. As such, regional geophysical surveys offer both an economic and environmentally friendly approach to large-scale exploration efforts through identification of regional scale structural controls that are indicative of metal endowment.
Imaging the Crust and Upper Mantle in the Southern Central Mediterranean with Joint Ambient Noise and Earthquake Surface Wave Tomography
Authors: Eckel Felix , El-Sharkawy Amr , Barberi Graziella , Scarfì Luciano , Langer Horst , Lebedev Sergei , Meier Thomas
Published: March 2024

Surface wave tomography has proven to be a very powerful tool for discerning complex crustal and upper mantle structures since it bypasses the necessity for local seismic sources and crustal corrections. This study presents a refined 3D model encompassing the crust and uppermost mantle in Southern Italy and the broader southern Central Mediterranean region, achieved through the joint inversion of ambient noise and earthquake data.Our dataset comprises 11,900 phase velocity dispersion curves, spanning 2 to 100 seconds, derived from ambient noise cross-correlations. Additionally, we incorporate 81,000 phase velocity curves covering 8 to 250 seconds, obtained through inter-station cross-correlations and averaging over single earthquake measurements. A thorough quality control process ensures the reliability of both datasets, which are seamlessly integrated using a correction factor derived from inter-station paths with overlapping measurements.Azimuthally anisotropic Rayleigh wave phase velocity maps are computed using a regularized least-square approach. These maps, showcasing directional variations in wave velocities, serve as the foundation for our 3D model. The inversion process employs a stochastic particle swarm optimization algorithm, enhancing the robustness and accuracy of the final model.The resulting 3D velocity model brings to light significant subsurface features, notably the subducted Calabrian and Hellenic slabs, alongside the identification of a delaminated high-velocity anomaly beneath Sicily. Additionally, the model captures details such as the transition from the Ionian Lithosphere to the Calabrian Slab, deformation of the Adriatic Lithosphere, and the dynamic flow of the asthenosphere beneath the Tyrrhenian Sea.
On the potential use of highly oxygenated organic molecules (HOM) as indicators for ozone formation sensitivity
Authors: Zhang Jiangyi , Zhao Jian , Luo Yuanyuan , Mickwitz Valter , Worsnop Douglas , Ehn Mikael
Published: March 2024

Ozone (O3), an important and ubiquitous trace gas, protects lives from harm of solar ultraviolet (UV) radiation in the stratosphere but is toxic to living organisms in the troposphere. Additionally, tropospheric O3 is a key oxidant, and source of other oxidants (e.g., OH and NO3 radicals) for various volatile organic compounds (VOC). Recently, highly oxygenated organic molecules (HOM) were identified as a new compound group formed from oxidation of many VOC, making up a significant source of secondary organic aerosol (SOA). The pathways forming HOM from VOC involve autoxidation of peroxy radicals (RO2), formed ubiquitously in many VOC oxidation reactions. The main sink for RO2 is bimolecular reactions with other radicals, HO2, NO or other RO2, and this largely determines the structure of the end products. Organic nitrates form solely from RO2 + NO reactions while accretion products (“dimers”) solely from RO2 + RO2 reactions. The RO2 + NO reaction also converts NO into NO2, making it a net source for O3 through NO2 photolysis.There is a highly nonlinear relationship between O3, NOx, and VOC. Understanding the O3 formation sensitivity to changes in VOC and NOx is crucial for making optimal mitigation policies to control O3 concentrations. However, determining the specific O3 formation regimes (either VOC- or NOx-limited) remains challenging in diverse environmental conditions. In this work we assessed whether HOM measurements can function as a real-time indicator for the O3 formation sensitivity based on the hypothesis that HOM compositions can describe the relative importance of NO as a terminator for RO2. Given the fast formation and short lifetimes of the low-volatile HOM (timescale of minutes), they describe the instantaneous chemical regime of the atmosphere. In this work, we conducted a series of monoterpene oxidation experiments in our chamber while varying the concentrations of NOx and VOC under different NO2 photolysis rates. We also measured the relative concentrations of HOM of different types (dimers, nitrate-containing monomers, and non-nitrate monomers) and used ratios between these to estimate the O3 formation sensitivity. We find that for this simple system, the O3 sensitivity could be described very well based on the HOM measurements. Future work will focus on determining to what extent this approach can be applied in more complex atmospheric environments. 
AMOC Stability amid Tipping Ice Sheets from Conceptual to Intermediate Complexity Models
Authors: Sinet Sacha , von der Heydt Anna S. , Ashwin Peter , Dijkstra Henk A.
Published: March 2024

The Atlantic Meridional Overturning Circulation (AMOC) and polar ice sheets are considered susceptible to critical transitions under climate change. Identified as core tipping elements, their collapse would have global and drastic consequences. Furthermore, the AMOC and polar ice sheets form a complex interacting system, where the collapse of one component can heavily impact the stability of others. In the worst case, this could result in a large-scale domino effect, otherwise known as a cascading tipping event.In this presentation, our focus is on assessing the stability of the AMOC in the presence of tipping Greenland ice sheet (GIS) and West Antarctica ice sheet (WAIS). While most existing studies agree on the destabilizing impact of a GIS collapse on the AMOC, the consequences of a WAIS collapse remain uncertain. A previous conceptual study suggested that a WAIS tipping event might actually prevent an AMOC collapse against both climate warming and increased GIS meltwater fluxes. Using a better conceptual model of the AMOC, we demonstrate that both the melting rate and natural variability associated with surface meltwater fluxes are decisive factors for this phenomenon to occur. Finally, we present preliminary findings in which the relevance of this stabilizing effect is investigated in the model of intermediate complexity CLIMBER-X.
Future AMOC recovery modulated by atmospheric water vapor shortwave absorption
Authors: Lee Doseok , Kim Hanjun , Kang Sarah
Published: March 2024

The amount of shortwave radiation absorbed by atmospheric water vapor is highly model dependent. This study examines how differences in the atmospheric water vapor shortwave radiation absorption affect the CO2-induced climate response pattern. We control the atmospheric water vapor shortwave radiation absorption in Community Earth System Model 1.2.2 (CESM1-CAM4-POP2) by altering the water vapor shortwave absorptivity parameter k by 60% to 120% of the default value. The pre-industrial control simulations with different k values are integrated for 150 years and additional 150 years are integrated after abruptly quadrupling CO2 concentrations. Regardless of the k value, the Atlantic meridional overturning circulation (AMOC) weakens in response to the quadrupling of CO2. However, the simulation with a higher k value exhibits a faster AMOC recovery approximately 30 years after the quadrupled CO2, with the lowest k simulation exhibiting a persistent AMOC weakening with no sign of recovery for the entire 300-year integration period. The faster AMOC restoration with a larger k value is attributed to the climatologically colder and saltier subpolar North Atlantic sea surface condition arising from the larger Arctic sea ice fraction due to colder temperature associated with stronger atmospheric shortwave absorption. The colder and more saline subpolar North Atlantic sea surface facilitates a more rapid destratification of surface density, establishing a favorable condition for the AMOC restoration. The faster restoration of the AMOC with the higher k value leads to a larger inter-hemispheric energy asymmetry followed by a more northward ITCZ shift as well as a stronger equilibrium climate sensitivity. This study demonstrates the complex interaction among different elements within the Earth system, encompassing radiation, sea ice, AMOC, and large-scale atmospheric circulation, suggesting a way to reduce uncertainties in future climate projections by improving the parameterization of shortwave radiation absorption by atmospheric water vapor.
Microbial response to climate-induced nutrient alterations in high Arctic freshwaters
Authors: Valiente Nicolas , Fontaine Laurent , Popp Andrea L. , Sundal Anja , Wei Jing , Dörsch Peter , Trier Kjær Sigrid , Hessen Dag O. , Eiler Alexander
Published: March 2024

In the Arctic, climate change leads to increased nutrient levels and organic carbon in freshwaters, caused by factors like permafrost thaw and growing populations of geese. Such alterations significantly impact freshwater ecosystems, potentially influencing community composition and diversity across various levels, including general microbial metabolism. We tested the hypothesis that a transition from autotrophy to heterotrophy occurs across a chronosequence of lakes in the high Arctic as a result of glacier retreat, influenced by distinct nutrient supplies and varying ecological succession statuses. To do so, we studied 5 lakes in the vicinity of Ny-Ålesund (Svalbard) following a chronosequence. The older lakes, closer to the fjord, were strongly impacted by birds, notably geese. For each lake, we tested the response to nutrients by adding an artificial nutrient solution with N and P, and the response to light or dark conditions. We incubated unfiltered water samples (80 mL) at 4 ºC in 120 mL flasks with atmospheric air as headspace. After 24h, samples for gases (O2, CO2, CH4 and N2O), nutrients (organic C, P and N) and eDNA (16S metabarcoding) were collected. Ar-corrected gas saturation of each GHG was used as a proxy of net metabolic changes. Regardless of the treatment applied, our results showed an increase in N2O saturation coupled with a decrease in O2 saturation after 24h in bird-impacted lakes, likely related to heterotrophic microbial activity. In such lakes, dark conditions promoted P accumulation, while N accumulated equally in light and dark incubations. In younger lakes (i.e., not impacted by birds), increased O2 saturation after 24h of incubation suggested that phototrophic metabolism was dominant. For nutrients, no significant pattern was observed for both light and dark incubations in younger lakes. Bacterial community composition differed between locations after 24h of incubation with a greater uniformity of species in younger lakes. This research advances our understanding of how nutrient enrichment affects biodiversity in the Arctic and metabolism in freshwater ecosystems.
Linking the gap between seismic and geodetic observations during the 2020-2022 lava fountains at Etna volcano
Authors: Currenti Gilda , Carleo Luigi , Bonaccorso Alessandro
Published: March 2024

Lava fountains at Etna volcano are spectacular explosive eruptions consisting of powerful jets of gas and solid particles that cause a huge impact both to air traffic and urban areas due to ash dispersal and fall-out.The evolution of a lava fountain at Etna is usually a gradual process that progresses from a weak strombolian activity, passes to a typical lava jet and ends with the formation of a sustained eruptive column. Typically, lava fountain events last from tens of minutes to few hours. The interaction of the magma with the surrounding rock during such eruptive episodes induces tremor (0.5 - 5 Hz) and ultra-small deformation (10-9 to 10-7) of the superficial crust and generates geophysical signals at a wide ranges of amplitudes and time scales. Seismometers can capture only the higher frequency content of such signals by measuring volcanic tremor. Due to the small amount of related deformation, the traditional geodetic methods, such as GPS and InSAR, are not able to reveal significant variations because of the low precision (GPS resolution > 1 cm) or very low sampling frequency (InSAR temporal resolution limited by satellite passages). This limit is overcome by using Sacks-Evertson strainmeter that measures the volumetric deformation of the surrounding rock with the highest achievable resolution (10-10 to 10-11) and in a very wide frequency range (10-7 to > 20 Hz). Thanks to its characteristics, the strainmeter is perfectly suitable to explore the full spectrum and the very small amplitudes of the strain signal exerted by the lava fountain episodes at Etna, covering the frequency gap between the seismic and the common geodetic techniques.In this work, we analyzed the co-eruptive strain changes recorded by the borehole strainmeter network concurrently with more than 60 lava fountain events that occurred at Etna volcano between 2020-2022. We investigated all the lava fountain events, highlighting the main characteristics of the eruptive phases and their transition that characterize such eruptions, both in the high and in the low frequency band. These characteristics furnish fundamental constraints to improve the characterization of eruptive processes that lead to lava fountain events.
High-resolution data products for precipitation monitoring from the WegenerNet 3D Open-Air Laboratory for Climate Change Research
Authors: Kvas Andreas , Fuchsberger Jürgen , Kirchengast Gottfried , Galovic Robert , Scheidl Daniel , Bichler Christoph , Foelsche Ulrich
Published: March 2024

The WegenerNet 3D Open-Air Laboratory for Climate Change Research, located in southeastern Austria in an area of about 22 km x 16 km around the city of Feldbach (46.93°N, 15.90°E), provides a unique setup for studying extreme hydrometeorological events such as heavy precipitation, hailstorms, and drought periods. Its 3D upper air instrumentation consists of a polarimetric X-band Doppler weather radar, a microwave radiometer for vertical profiling of temperature, humidity, and cloud liquid water, an infrared cloud structure radiometer, and a water-vapor-mapping GNSS station network. This enables comprehensive upper-air monitoring of precipitation events with high spatial- and temporal resolution in near real-time. These 3D sensors complement the high-density WegenerNet hydrometeorological ground station network, which covers the area by 156 stations measuring precipitation, temperature, humidity, and (at selected locations) wind and soil parameters. This highly synergistic measurement setup enables robust internal cross-evaluation, calibration and quality control for obtaining reliable observations and derived WegenerNet data products. The 3D instrumentation is operational since mid-2021, providing a consistent and growing data record of nearly three years so far.We present the first release of upper air data cube products derived from the WegenerNet 3D Open-Air Laboratory, aimed at studying (heavy) precipitation events. This includes radar-derived precipitation and hydrometeor classification with 500 m spatial resolution and 2.5 min time resolution at multiple altitude levels, cloud coverage and base height maps with 10 min resolution, vertical profiles of temperature and humidity, atmospheric stability indices with 10 min resolution, and GNSS- and radiometer-derived tropospheric path delays as well as precipitable water vapor with 2.5 min to 10 min resolution. In addition to these Level 2 data products, quality-controlled Level 1 observational data, such as radar reflectivities and differential phase measurements, GNSS tropospheric delays and gradients, and infrared and microwave brightness temperatures are also made available to the scientific community. These data products, and accompanying metadata, are available in the form of user-friendly 3D data cubes accessible through the WegenerNet Data Portal.
Exploring dML Correction and Correlation with Site Parameters for Improved ML estimation in Taiwan
Authors: Kuo Chun-Hsiang , Chen Hsin-Yu , Yen Horng-Yuan
Published: March 2024

Local magnitude (ML) is still commonly used for regional seismic networks because of it can be estimated fast and easily. To represent ML of an earthquake event, an average value obtained from a couple of stations are utilized. However, calculation of ML is influenced by diverse geological characteristics at each seismic station, leading to variations in computed values, and thus a station correction term Si had been suggested. This study analyzes a station adjustment term, i.e., dML, which indicates the difference between the earthquake event magnitude and the magnitudes obtained from individual stations. For small or medium magnitude earthquakes, which may only be recorded by stations located close to the epicenter. In such cases, all stations may be situated on either hard rock or soft soil, potentially causing bias of ML estimation without considering station adjustment. In addition, we also assess dML between surface and downhole stations for a recently installed surface-downhole network in Taiwan. Those downhole stations have better ability for recording weak seismic signals and are expected to enhance the precision of earthquake localization and monitoring capabilities, especially for regional small earthquakes. By applying dML adjustment, those high-quality downhole stations are able to be incorporated in ML estimation. Since various site parameters, like VS30 (time average S-wave velocity of the top 30-meter layers), Z1.0 (sedimentary depth), and fd (peak frequency), have been derived in Taiwan, we try to determine if it is possible to estimate the correlation between dML and the site parameters of each station. By implementing dML correction, we anticipate contributing to greater consistency in earthquake catalogs, enhancing the accuracy of seismicity rates for seismic hazard analysis.
First observations of whistler waves in Mercury’s magnetosphere by BepiColombo/Mio spacecraft
Authors: Sahraoui Fouad , Ozaki Mitsunori , Yagitani Satoshi , Kasaba Yasumasa , Kasahara Yoshiya , Matsuda Shoya , Omura Yoshiharu , Hikishima Mitsuru , Mirioni Laurent , Chanteur Gérard , Kurita Satoshi , Nakazawa Satoru , Murakami Go
Published: March 2024

Whistler-mode chorus waves are natural electromagnetic emissions known to play a key role in electron acceleration and loss mechanisms via wave–particle interactions in planetary magnetospheres. Chorus waves have not yet been detected in Mercury’s magnetosphere due to the limited capabilities of the instruments onboard the spacecraft that already visited the planet. Here, we present the first detection of chorus waves in the localized dawn sector during the first and second Mercury flybys by the BepiColombo/Mio spacecraft. Mio’s search coil magnetometers measured chorus waves with tens of picotesla intensities in the dawn sector, while no clear wave activity was observed in the night sector. The simulation results suggest that this dawn-dusk asymmetry could be explained by the impact of background magnetic field inhomogeneities on the nonlinear wave generation process. Potential direct comparisons with electron data will be discussed. This observational evidence is crucial for understanding the dynamics of energetic electron in the localized dawn sector of Mercury’s magnetosphere.
 Understanding UTLS Dynamics in the Tropics during Deep Convection: Insights from 205 MHz ST Radar 
Authors: School Parambath Sujithlal , Karathazhiyath Satheesan , Kottayil Ajil
Published: March 2024

Deep convection plays a crucial role in transporting atmospheric components, including mass, momentum flux, heat, and moisture, across various layers of the atmosphere. This transport gains particular significance in the Upper Troposphere and Lower Stratosphere (UTLS) region, an area that remains relatively unexplored but holds considerable importance in the context of the changing climate scenario. In response to the identified scientific gap, a dedicated initiative was launched to investigate the impact of thunderstorms in the UTLS over Kochi,India. This region is Situated in the tropical coastal zone and recognized as the gateway to the Indian monsoon, It exhibits distinctive features, including frequent deep convective activities. Utilizing the capabilities of the 205 MHz ST Radar at Cochin University of Science and Technology (CUSAT), renowned for its high spatio-temporal resolution, this campaign sought a comprehensive understanding of the impact of thunderstorms on the less-explored UTLS region. An experiment, conducted at ACARR from November 3 to November 10, 2022, involved a 24-hour observation period using the ST radar along with other instruments, including microwave radiometer, Disdrometer, AWS observation, ceilometer, and MRR, enabling multiplatform observation of dynamic and thermodynamic states during post-monsoon thunderstorms. These events exhibited characteristics of deep convection, showcasing unique signatures in the upper troposphere and lower stratosphere. The radar captured robust updrafts, reaching maximum speeds of 4-5 m/s and extending from the mid-troposphere to the lower stratosphere. Hodographs constructed during convective activities unveiled strongly'veered' winds extending into the upper troposphere. This observation highlighted the complexity of convective processes in this tropical region. A pivotal aspect of the study centered on calculating vertical and horizontal momentum flux during thunderstorm events in the UTLS region. This analysis provided valuable insights into the intricate momentum exchange between different atmospheric layers, offering a deeper understanding of the convective systems' dynamics in the UTLS region. We have observed 5-6 times enhancement in the vertical momentum flux during convective activity in the UTLS and 4-5 times in the mid-troposphere. We also estimated turbulence in the UTLS region during this period using the spectral width method. We also tried to understand the existence of any periodic wind behavior in the tropopause region using a periodogram. Detailed statistics are presented in this paper.
Leveraging the Power of Graph Neural Networks in Environmental Time Series Anomaly Detection 
Authors: Lasota Elżbieta , Polz Julius , Houben Timo , Schmidt Lennart , Schäfer David , Bumberger Jan , Chwala Christian
Published: March 2024

Efficient quality control (QC) of time series data from environmental sensors is crucial for ensuring data accuracy and reliability. In this work, we turn to machine learning, specifically Graph Neural Networks (GNN), to elevate QC efficiency for large datasets originating from sparsely distributed sensors. Our proposed model, specifically tailored for anomaly detection as a vital aspect of QC, combines graph convolution (GC) and Long Short-Term Memory (LSTM) layers to capture both spatial dependencies and temporal patterns in the time series data. The focus on anomaly detection enables the identification of deviations or irregularities in the signal, providing insights into important events, faults, or disturbances within the data.We conducted experiments using two distinct types of labeled data: three months of data in 2019 from 20 Commercial Microwave Links (CML) distributed around Germany and a 2.5-year period (June 2014 to December 2016) of soil moisture data from the TERENO SoilNet network in Hohes Holz, Germany. These datasets, encompassing an impressive 2.5 million samples, pose challenges in QC due to diverse dynamics, signal anomalies, and variations in temporal resolution and spatial densities of observations. The classification results demonstrated satisfactory performance, with Matthews Correlation Coefficients of over 0.6 and 0.8 for the CML and SoilNet datasets, respectively. To evaluate the added value of processing the spatial information provided by neighboring sensors, we also compared the results of our final GNN with a baseline model that uses the same LSTM layers but disregards the GC layer, which integrates the neighboring information. The GNN model exhibited improved performance, as evidenced by 5-fold cross-validation mean Area Under the Receiver Operating Characteristic Curve (AUC) values of 0.934 and 0.971 for the CML and SoilNet data, respectively. In contrast, the baseline model yielded mean AUC values of 0.877 and 0.950, highlighting the effectiveness of incorporating the information from neighboring sensors via the GC layers to enhance anomaly detection for environmental sensor time series data.
Transparent framework to assess the revision of climate pledgesafter the first Global Stocktake
Authors: Tanaka Katsumasa , Tibrewal Kushal , Ciais Philippe , Boucher Olivier
Published: March 2024

To assess the impact of potential future climate pledges after the first Global Stocktake, we propose a simple, transparent framework for developing emission and temperature scenarios by country. We show that current pledges with unconditional targets lead to global warming of 1.96 (1.39-2.6)°C by 2100. Further warming could be limited through i) commitment to mid-century net-zero targets for all countries and earlier net-zero targets for developed countries, ii) enhancement of the Global Methane Pledge, and iii) ambitious implementation of the Glasgow Leaders’ Declaration on Forests and Land Use. Our analysis further shows that overshooting 1.5°C is unavoidable, even with supplementary climate engineering strategies, suggesting the need for strategies to limit further overshoot and ultimately reduce the warming towards 1.5°C.ReferenceTibrewal, K., K. Tanaka, P. Ciais, O. Boucher (2023) Transparent framework to assess the revision of climate pledges after the first Global Stocktake.     arXiv:2312.16326 http://arxiv.org/abs/2312.1632
Seasonal scale records of hydroclimate and temperature derived from clumped isotopes of land snail shells from the Chinese Loess Plateau 
Authors: Guo Jingjing , Zong Xiulan , Yang Wenru , Dong Jibao , de Winter Niels , Yan Hong , Song Yougui , Sun Youbin , Peterse Francien , Ziegler Martin
Published: March 2024

Quantitative reconstructions of past precipitation and temperature variations at the seasonal scale are essential for understanding East Asian Monsoon (EAM) dynamics. However, archives capable of capturing seasonal climate signals on land are limited. Here, we present high-resolution stable oxygen isotope (δ18Oshell) and carbonate clumped isotope (Δ47) data from modern and fossil land snail shells collected from the eastern (Lingbao, LB) and western (Yuanbao, YB) edge of the Chinese Loess Plateau (CLP).The δ18Oshell of modern snails similarly reflect the seasonal variation in precipitation oxygen isotopic signals at both locations. The Δ47-derived temperatures for the same snails indicate that the seasonal temperature difference (summer vs. winter) is larger at YB than LB, aligning with modern observations from the western edge of the CLP, where a higher elevation results in a larger seasonality. The averaged whole shell Δ47-derived temperatures (T47) from modern Cathaica pulveritrix shells at LB and their related Cathaica richthofeni snails at YB resemble growing season temperatures. Interestingly, the T47 of shells of three smaller snail species, Pupilla muscorum, Kaliella lamprocystis, and Vallonia sp. are substantially (up to 10 ºC) lower than those of C. richthofeni from the same site. The temperature difference between snail species and among specimens suggests that optimal living conditions and micro-environments likely play a key role in the temperature signal recorded in the snail shells.Fossil snails from LB show a larger variability in δ18Oshell  during the Last Glacial Maximum (LGM, 19–18 ka), with wet season values approximately 3‰ more depleted than modern shells. In contrast, the seasonal temperature difference in fossil snails is smaller than in their modern counterparts, and growing season temperatures are ~10 °C lower than the present at LB. Fossil shells from YB also have a more negative δ18Oshell during the last deglaciation (14‒13 ka) than their modern counterparts. Similar to LB snails, the whole shell T47 of fossil snail shells at YB indicates that growing season temperatures were ~10 °C lower than recorded by their modern counterparts, and the temperature variability on a seasonal scale is smaller than in modern snails. The relatively large variability, negative δ18Oshell values and low T47 values in fossil shells suggests weaker evaporation or longer water vapor transportation under glacial conditions. While snail shells can capture high-resolution climate signals, variations in living conditions and micro-environments among snail species and specimens should be considered in future Δ47-based temperature studies and their applications.