bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling interactions of water fluxes with species and structural diversity in temperate forests
Authors: Bohn Friedrich J. , Attinger Sabine , Kihm Charlotte , Hildebradt Anke
Published: February 2023

Ecosystem functions of temperate forests are expected to be severely impacted by future climate change - particularly hydro-meteorological extremes (heavy precipitation events, droughts, and heat waves) that will increase in frequency, duration, magnitude, and extent. Previous studies have shown that both structural and tree species diversity may act as buffers against the impacts of climate extremes.To better understand the influence of structural and tree species diversity, we use two models to analyze the influence of species and structural diversity on hydrologic dynamics during recent drought events. The well-equipped test sites are located in central Germany and represent typical forests in this area. One model is the individual forest gap model FORMIND. Using a newly developed technique, it allows us to analyze local heterogeneous patterns on a 2 meter scale of carbon and water cycling, flow, and water stress, and their relationship to structural and species diversity. The second model is mHM, a mesoscale hydrological model. We parameterize mHM for two catchments in central Germany (Nägelstedt and Upper Saale). We further analyze the relevance of local heterogeneity in structural and species diversity and the resulting local heterogeneity in water fluxes on the fluxes at the mesoscale.This two-model and interdisciplinary workflow allows us to consider various soil-plant-atmosphere interactions in drought disturbed ecohydrological systems
Meridional Heat Transport in the DeepMIP Eocene ensemble: non-CO2 and CO2 effects
Authors: Kelemen Fanni Dora , Steinig Sebastian , de Boer Agatha , Zhu Jiang , Chan Wing-Le , Niezgodzki Igor , Hutchinson David K. , Knorr Gregor , Abe-Ouchi Ayako , Ahrens Bodo
Published: February 2023

The total meridional heat transport (MHT) is relatively stable across different climates. Nevertheless, the strength of individual processes contributing to the total transport are not stable. Here we investigate the MHT and its main components especially in the atmosphere, in five coupled climate model simulations from the Deep-Time Model Intercomparison Project (DeepMIP). These simulations target the Early Eocene Climatic Optimum (EECO), a geological time period with high CO2 concentrations, analogous to the upper range of end-of-century CO2 projections. Preindustrial and early Eocene simulations at a range of CO2  levels (1x, 3x and 6x preindustrial values) are used to quantify the MHT changes in response to both CO2 and non-CO2 related forcings. We found that atmospheric poleward heat transport increases with CO2, while the effect of non-CO2 boundary conditions (e.g., paleogeography, land ice, vegetation) is causing more poleward atmospheric heat transport on the Northern and less on the Southern Hemisphere. The changes in paleogeography increase the heat transport via transient eddies at the mid-latitudes in the Eocene. The Hadley cells have an asymmetric response to both the CO2 and non-CO2 constraints. The poleward latent heat transport of monsoon systems increases with rising CO2 concentrations, but this effect is offset by the Eocene topography. Our results show that the changes in the monsoon systems’ latent heat transport is a robust feature of CO2 warming, which is in line with the currently observed precipitation increase of present day monsoon systems.
Quantifying methane super-emitters from oil and gas production in Romania with the AVIRIS-NG imaging spectrometer
Authors: Kuhlmann Gerrit , Brunner Dominik , Emmenegger Lukas , Schwietzke Stefan , Zavala-Araiza Daniel , Thorpe Andrew , Hueni Andreas , Röckmann Thomas
Published: February 2023

Reported methane (CH4) emissions from Romania's onshore oil and gas (O&G) production contribute 16% to onshore O&G emissions in Europe (55 out of 346 kt, IEA estimate). In October 2019, CH4 emissions from the O&G infrastructure were measured during the ROMEO campaign with a wide range of in situ measurement techniques in southern Romania. The measurements confirmed a log-normal distribution of emissions with a small number "super-emitters" contributing strongly to the overall emissions.However, overall emissions remain uncertain because some CH4 super-emitters are difficult to identify with ground-based campaigns due to the large number of potential sources and sometimes elevated emission plumes. In contrast, airborne imaging spectrometers are well suited for identifying super-emitters due to their good spatial coverage and sensitivity to vertical columns. To identify super-emitters, the airborne AVIRIS-NG imaging spectrometer was flown in July 2021 in southern Romania covering an area of about 3000 km2 that contains about 80% of known O&G infrastructure in the region.CH4 enhancements in the AVIRIS-NG lines were retrieved using a quantitative matched-filter method. In total, 38 emission plumes were identified that were assigned to 26 individual sources. Emissions were estimated using the integrated mass enhancement approach and ranged from 13 to 515 kg/h, which suggests annual emissions of about 30 kt assuming continuous emission rates. The sites were visited by ground crews, who confirmed that at least 17 of the sources were also active in December 2022.The observed 30 kt/a from only 26 sources already represent more than half of the reported emissions from the onshore O&G emissions in entire Romania. The campaign demonstrates the importance of airborne imaging spectrometers to identify and quantify CH4 super-emitters for monitoring CH4 emissions from O&G infrastructure.
The Nord Stream underwater explosions: location, classification and yield estimation
Authors: Lund Björn , Eggertsson Gunnar , Tryggvason Ari , Schmidt Peter , Roth Michael , Larsen Tine , Voss Peter , Dahl-Jensen Trine , Rinds Nicolai , Köhler Andreas , Goertz-Allmann Bettina , Alvizuri Celso , Schweitzer Johannes , Oye Volker , Weidle Christian , Dunham Eric M.
Published: February 2023

Soon after midnight on 26 September 2022 the Swedish National Seismic Network, using data from Sweden, Denmark and Germany, automatically detected a seismic event in the Baltic southeast of the Danish island of Bornholm. The event was followed 17 hours later by a second, more complex, event northeast of Bornholm. The automatic locations of the events were within 6-9 km of later reported gas leaks in the Nord Stream 1 and 2 pipelines. Using recently developed, machine learning based, classifiers both events were automatically classified as explosions. Subsequent analysis of the second event revealed that it was in fact two blasts, separated by about 7 seconds. As the events occurred in the transition zone between the Fennoscandian Shield and the younger terranes of Denmark and northern Germany, 3D tomographic P- and S-velocity models were developed to improve locations and assess uncertainties, bringing the locations closer to the pipelines. Spectral analysis of the blast data show clear reverberations consistent with underwater explosions and a blast depth of approximately 75 m. The conclusion that the events are underwater blasts are further supported by data on known underwater explosions and a few earthquakes in the area. The magnitude of the first event was estimated at ML 1.9 and the combined second and third event had ML 2.3. Estimating the equivalent yield in the explosions is, however, non-trivial. Comparison to ground truth underwater explosions suggests yields of one to a few hundred kilos of equivalent TNT. The contribution to the seismic energy from suddenly outflowing methane gas is under investigation and results will be included in the presentation.
Characterisation of large-scale urban fire emissions by inverse modelling
Authors: Launay Emilie , Hergault Virginie , Bocquet Marc , Dumont Le Brazidec Joffrey , Roustan Yelva
Published: February 2023

Large-scale fires such as warehouse fires that have occurred in recent years or dramatic accidents like the Paris Notre-Dame Cathedral fire in 2019 have stressed the need to develop means of assessing the toxicity risks to the population and the environment of smoke plumes. A key challenge is to quickly provide the authorities with information on the areas impacted by the plume and the pollutant concentration levels to which the population is likely to be or to have been exposed. The Laboratoire Central de la Préfecture de Police (LCPP) aims to deploy a number of devices for measuring pollutants and tracers of smoke combustion during a fire. Subsequently, the application of an atmospheric dispersion model within the framework of a data assimilation approach should provide a source characterisation and a finer estimate of the concentration levels at points of interest.To characterise the source, noticeably the released mass of pollutants and the emission height linked to a plume rise, an inverse problem method has been implemented. It is based on a Bayesian Markov Chain Monte Carlo (MCMC) technique meant to quantify the uncertainties associated with the emission estimation. Since the emission height strongly influences the atmospheric dispersion in the vicinity of the source, two approaches are used to estimate it. The first one consists in finding the emission time rate for each considered height and the second one consists in focussing on a single emission height and its associated emission time rate using a discrete distribution to describe the vertical profile. We use the Lagrangian Parallel Micro Swift Spray (PMSS) model developed by AriaTechnologies fed with meteorological fields provided by Météo-France to represent the atmospheric dispersion of smoke.Our inverse method is applied to a large warehouse fire that occurred in Aubervilliers near Paris in 2021 using real observations. Abnormal concentrations of particulate matter were recorded, with a peak at 160 µg.m-3, located in the centre of Paris about 6 km from the source. They were collected by the LCPP and AirParif, the local air quality agency, and are used to retrieve the emission with a quantification of uncertainties and a sensitivity analysis of model error. The resulting emission height of the source, mainly between 200 and 300 m, coincides with the terrain observation for an emission rate of less than 1000 kg/h throughout the duration of the fire. A sensitivity analysis to the initial approximation of the source (the prior) shows its importance. It suggests to improve our method by incorporating the statistical parameters of the observation error into the MCMC method.
Effects of future Arctic sea-ice loss and ocean warming on winter temperature extremes in the Northern Hemisphere
Authors: Lo Eunice , Mitchell Dann , Watson Peter A. G. , Screen James A.
Published: February 2023

Rapid Arctic warming and sea-ice loss have been observed in recent decades, and these trends are likely to continue in the future. Research has shown that Arctic changes affect weather and climate across the Northern Hemisphere. These changes, especially those in the extreme ends, can adversely impact communities and ecosystems. Recent development of the Polar Amplification Model Intercomparison Project (PAMIP) means that large ensembles of standardised climate experiments are now available for examining the effects of future Arctic changes on extreme weather in a coordinated way. Based on present-day and future (2°C global mean warming above pre-industrial levels) PAMIP model simulations, I will show the projected responses of winter hot and cold extremes (at the 20-year return period) to future Arctic sea-ice loss and ocean warming separately. I will focus on land areas in the Northern Hemispheric mid- and high latitudes where responses are expected to be largest. I will discuss the importance of considering the effect of sea-ice concentration loss together with that from ocean warming, which is not routinely done in the literature.
Soil uptake of VOCs exceeds production when ambient VOCs are readily available
Authors: Jiao Yi , Kramshøj Magnus , Davie-Martin Cleo L. , Albers Christian Nyrop , Rinnan Riikka
Published: February 2023

Volatile organic compounds (VOCs) is a group of highly reactive gaseous species in the atmosphere with significant environmental implications, such as influencing air quality and Earth’s radiation balance. Natural ecosystems constitutes a large part of VOCs inventory with vegetation as well-known sources and soils as potential unidirectional interface yet relatively less studied. Here, we collected soil samples from two representative temperate ecosystems: beech forest and heather heath, and incubated them under manipulated conditions, such as at different temperatures,  and/or exposed to different ambient VOC levels, using a dynamic flow-through system coupled with a PTR-ToF-MS, from which production and/or uptake rates of some selected VOCs were measured and calculated. Results showed that these soils were natural sources of a variety of VOCs, and their emission strength and profile were influenced by soil biogeochemical properties (e.g., soil organic matter, moisture) and temperature. These soils were switched to natural sinks of most VOCs when supplying VOC substrates to the headspace of the enclosed soils at parts per billions level, and the sink size positively responded to the amount of VOCs available in the ambient air. Further analysis indicated that the observed VOC uptake by soils were likely driven by microbial metabolism plus a minor contribution from physical adsorption to soil particles. Overall, our study suggests that soil uptake of VOCs may conceal the simultaneous production and turn it into VOC sinks when ambient VOCs become readily available, such as significant VOC sources existing near surface, thereby regulating the net performance of ecosystem exchange of these environmentally important trace gases.
Sensitivity of the Cosmic Ray Neutron Sensor (CRNS) to Seasonal Biomass Dynamics in Cherry and Olive Orchards
Authors: Al-Mashharawi Samir K. , El Hajj Marcel M. , Johansen Kasper , McCabe Matthew F. , Steele-Dunne Susan
Published: February 2023

Biomass estimation is important in many applications, such as carbon sequestration and precision agriculture. Developing a reliable method for biomass estimation from satellite, airborne and near-surface remote sensing sensors is an ongoing task due to the large uncertainty in current methods, which are often related to sensor limitations. Indeed, signals from optical sensors and synthetic aperture radar at high and medium frequencies suffer from saturation issues at high biomass levels. The Cosmic-Ray Neutron Sensor (CRNS) is a new non-invasive near-surface sensor used primarily to estimate soil water content (SWC), but it has also shown potential for retrieving other hydrological and environmental parameters such as biomass water equivalent and snow depth. The CRNS detects and counts the number of neutrons controlled by hydrogen atoms in the soil, air just above the ground, and vegetation. Biomass attenuates the intensity of cosmic ray neutrons, hence the ability to estimate biomass from a CRNS. Recent studies have used CRNS measurements to estimate biomass changes in crop areas and forest stands, while the use of CRNSs in orchards is limited. The objective of this study is to explore the potential of two CRNSs to estimate the biomass variation in irrigated cherry and olive tree orchards. The olive tree orchard is located in an arid region in northern Saudi Arabia (plantation density of 1667 trees/hectare) with an average tree height of 3 m and canopy diameter of 2 m. The cherry field is located in southern France (plantation density of 260 trees/hectare) with an average tree height of 3.5 m and canopy diameter of 5.5 m. Several soil moisture probes recording soil water content (SWC) at 15-min intervals at both sites were installed at different depths within the CRNS footprint. SWC measurements were used to assess the variations in the sensitivity of CRNS to soil moisture with increasing biomass. Tree parameters (height, canopy width, canopy length, leaf area index, and diameter at breast height) were measured in situ to estimate biomass using allometric equations. In addition, repetitive Light Detection and Ranging (LiDAR) scanning was performed over the cherry field to detect canopy volume changes over time. The results showed that the CRNS is sensitive to SWC variation, and this sensitivity is controlled by biomass evolution, indicating that CNRS measurements can also be used to estimate biomass. The sensitivity of CRNS neutron counts to SWC in the early season (before blooming) was twice as high as that during the mid- and late growing seasons (maximum leaf cover). The Cornish Pasdy model­, which models the measured neutron counts as a function of SWC and biomass contribution, was calibrated and then inverted to estimate the biomass in the cherry and olive tree orchards. 
Deep learning for automatic flood mapping from high resolution SAR images
Authors: Dupeyrat Arnaud , Almaksour abdullah , Vinholi Joao , friberg tapio
Published: February 2023

 With the gradual warming of the global climate, natural catastrophes have caused billions of dollars in damage to ecosystems, economies and properties. Along with the damage, the loss of life is a very serious possibility. With the unprecedented growth of the human population, large-scale development activities and changes to the natural environment, the frequency, and intensity of extreme natural events and consequent impacts are expected to increase in the future.  To be able to mitigate and to reduce the potential damage of the natural catastrophe, continuous monitoring is required. The collection of data using earth observation (EO) systems has been valuable for tracking the effects of natural hazards, especially with their near real-time capabilities for tracking extreme natural events. Remote sensing systems from different platforms also serve as an important decision support tool for devising response strategies, coordinating rescue operations, and making damage and loss estimations. Synthetic aperture radar (SAR) imagery provides highly valuable information about our planet that no other technology is capable of. SAR sensors emit their own energy to illuminate objects or areas on Earth and record what’s reflected back from the surface to the sensor. This allows data acquisition day and night since no sunlight is needed. SAR also uses longer wavelengths than optical systems, which gives it the unsurpassed advantage of being able to penetrate clouds, rain, fog and smoke. All of this makes SAR imagery unprecedentedly valuable in sudden events and crisis situations requiring a rapid response. In this talk we will be focusing on flood monitoring using our ICEYE SAR images, taking into account multi-satellites, multi-angles and multi-resolutions that are inherent from our constellation and capabilities. We will present the different steps necessary that have allowed us to improve the consistency of our generated flood maps.
Electron distribution functions measured by the SWA/EAS sensor during the first perihelia of the Solar Orbiter mission
Authors: Berthomier Matthieu , Lenc Andrew , Nicolaou Georgios , Owen Christopher , Lewis Gethyn , Wicks Robert , Fortunato Vito , Horbury Timothy
Published: February 2023

We present an updated procedure developed to calibrate flight data from the Electron Analyser System (EAS) of the Solar Wind Analyzer (SWA) instrument onboard Solar Orbiter. By imposing specific physical conditions on the data set, like isotropy of the core electron population, and by comparing electron fluxes measured by the two EAS heads, we are able to derive consistent correction factors of the raw data set. The procedure is shown to improve the quality of the merging of the two heads dataset. We evaluate the impact of these corrections on ground moment calculation and on specific features of the electron pitch-angle distributions during the first perihelia of the mission. Anisotropy of the component of the pitch-angle electron distribution in different energy ranges is analysed. Detailed properties of specific features of the distribution including strahl and anti-strahl electrons are examined with this updated procedure.
Stress testing the impacts of climate change on water quality permitting across England
Authors: Hankin Barry , Heaney Tony , Eccleston Paul , Simmons Paul , Garratt Alex , Wang Changgui
Published: February 2023

This presentation reports on the results of simulating 17 regulatory SIMCAT water quality models for England based on using the CEH Future Flows dataset. The de-biased uplifts were generated across 140 flow gauges comparing 2060-2080 with 2000-2020 for 11 ensembles, and kriged across the country to capture the gradients and apply river reach-specific uplifts in headwater and along-reach flows (for mean and 95 percentile exceedance flows). The resulting uplifts were applied using a recently developed UKWIR workbook and the statistical water quality models were simulated for a range of sanitary and chemical determinands (BOD, ammonia, dissolved oxygen, total and soluble phosphorus, nitrate, PFOS, cadmium and cypermethrin) to assess the potential change to Sewage Treatment Work permits.Failure of target EQS and 10% deterioration of quality are analysed, computing the necessary adjustment to water quality permits to meet the water quality standards in the future. Ensemble uplifts representative of upper, lower and mid flows were used (focussing on the low flows) and their predicted annual average reduction. The sensitivity of the results to travel time, seasonality and temperature are investigated, and outputs are compared with recent process-based modelling using the EA HYPE model of England.
Enhancing the seasonal forecasts from large-scale hydro-climate services to better meet the local conditions
Authors: Du Yiheng , Clemenzi Ilaria , Pechlivanidis Ilias
Published: February 2023

A key challenge in continental and global hydro-climate services deals with the incomplete (or even lack of) incorporation of local knowledge and data from the users. Here, we demonstrate the regional skill of seasonal forecasts from large-scale hydro-climate services, while we present a framework that accounts for local data and with the use of machine-learning enhances the seasonal forecasts by better capturing the local information. Five European case studies subject to different hydro-climate conditions and user needs are selected. We test our framework using the E-HYPE hydrological model forced by bias-adjusted ECMWF SEAS5 seasonal meteorological forecasts. We firstly assess the skill of seasonal hydrological forecasts using pseudo-reality and “real” local observations as reference. The skill assessment is driven by the local needs and hence it is conducted for different target hydro-climatic variables and conditions (i.e. floods and droughts). This first evaluation sets the benchmark for quantifying the added value from a machine-learning enhanced hydro-climate service. We next introduce a post-processing workflow to take advantage of the available local observations and potentially improve the forecasting skill. Here, quantile mapping and machine-learning post-processors are tested in the case study areas to further tune the output from the European hydro-climate service towards the local observations. Results from these hybrid seasonal forecasts show potentials to meet the local conditions and consequently address the user expectations from the service. The current work is highlighting the way forward for machine-learning enhanced services that allow tailoring large-scale hydro-climate services using local knowledge and data.
Increased complexity of seismic ground motion prior and during the 2014 Holuhraun eruption, Iceland
Authors: Sudibyo Maria R.P. , Eibl Eva P.S. , Hainzl Sebastian , Ohrnberger Matthias
Published: February 2023

The complexity of time series can be quantitatively measured using Permutation Entropy (PE). PE has recently been introduced as a potential tool in eruption forecasting by applying it to the seismic time series. Examples of successful applications are the eruptions at Strokkur Geyser, Iceland, the 1996 eruption of Gjálp, Iceland, and the eruptions of Shinmoedake volcano, Japan, in 2011, 2017, and 2018. While PE is able to show temporal changes prior to an eruption, these features are not always prominent. To improve this method, we calculate PE not only for the amplitudes of the seismic signals but also for the seismic instantaneous phases, called Phase Permutation Entropy (PPE). To understand the difference between PE and PPE, we performed synthetic tests by creating several synthetic waveforms using different numbers of sin wave superposition. We used more wave superposition with different frequencies to create complex waves containing broader frequency spectrum, while less superposition is used to create simpler waves containing narrower frequency spectrum. PE and PPE values are both low for simple waves and high for complex waves, but their absolute values differ, which might contain valuable information. The gap, dP = PE-PPE, is found to be smaller for complex waves compared to the more simple waves.  We then calculated PE and PPE for seismic data recorded from January 2014 to December 2015, which covered the eruption period of Holuhraun in Iceland. During the time of quiescence, both PE and PPE exhibit a long period variation which seems to be seasonal. Calculating dP weakens the long period noise and generates a more stable baseline.  We observe that the temporal variation of dP started to decrease below the baseline after 24 May 2014, indicating that the ground motion got more complex. An abrupt drop of dP to its lowest level was observed on 16 August 2014, when the dyke started to propagate from Bardarbunga to Holuhraun. While dP increases after the onset of eruption on 29 and 31August 2014, there is no prominent feature between the dyke propagation and the onset of the eruptions.  During the eruption period, dP stays lower than the background dP, indicating a higher ground motion complexity compared to the quiescence time. After January 2015, the gradual increase of dP back to the baseline level is clearly observed, showing the method’s potential to foresee the end of the eruption.
Conceptualizing the long-term interactions between climate services and adaptation to hydrometeorological extremes
Authors: Biella Riccardo , Khatami Sina , Brandimarte Luigia , Mazzoleni Maurizio , Di Baldassarre Giuliano
Published: February 2023

Climate services are expected to deliver better climate adaptation by providing decision-makers with timely, salient, credible, legitimate, and accessible climate information. Nonetheless, climate services’ impact on long-term adaptation remains poorly understood due to their ambiguous protocols, quality standards, and inadequate monitoring and evaluation processes.The aim of this study is to present the underpinnings of a framework representing the causal mechanisms and feedback interactions between adaptation to hydrometeorological extremes, i.e. floods and droughts, and climate services among the partner living labs of the I-CISK project (https://icisk.eu). To this end, a qualitative investigation based on interviews and surveys of the living labs’ stakeholders is performed. Following, the findings from the qualitative analysis are iteratively discussed with the stakeholders and presented as a causal loop diagram, highlighting feedback loops in the coupled human-climate system. Finally, the emerging dynamics are described using system archetypes.This research offers a systemic tool for evaluating the long-term dynamics of adaptation to hydrometeorological extremes while building the bases for further research in the living labs. Moreover, it shows the efficacy of system dynamics tools for informing adaptive policy-making.
Simulation of equilibrium scour hole development around riprap sloping structure using the numerical model
Authors: Harasti Antonija , Gilja Gordon
Published: February 2023

This paper investigates effect of scour adjacent to the bridge piers with installed riprap as the scour countermeasure. A riprap sloping structure is a conical placement of launchable stones around the bridge pier commonly used as erosion protection. Riprap sloping structure affects the flow in similar manner to groynes, shifting the scour hole downstream of the toe of the structure. Assuming that the installation of the riprap erosion protection deflects the scour hole development downstream of the bridge, experimental model is developed to represent natural environment under different flow scenarios. The 3D model requires calibration of numerical parameters to accurately simulate the prototype conditions – e.g. cell mesh size, turbulence model, and roughness associated with natural riverbed and the riprap sloping structure. Calibration of the Flow-3D numerical model was performed against the flow measurements conducted during field campaign. Flow measurements were collected using Acoustic Doppler current profiler on 20 transects along the river section adjacent to the bridge. Two independent surveys were conducted: for 30 % flow duration and 60 % flow duration (mean flow conditions). After obtaining the results, cross-sectional velocities were analyzed in 3 characteristic transects (upstream, downstream and at the bridge opening). Finally, good agreement was achieved between the model and measured flow field across all transects, enabling numerical setup to be reliable for simulating rare flood events, and associated scour development. Acknowledgments:This work has been supported in part by Croatian Science Foundation under the project R3PEAT (UIP-2019-04-4046).
Assessing the Surface-Layer Stability over China Using Long-Term Wind-TowerNetwork Observations
Authors: Li Jian
Published: February 2023

Surface-layer stability is important in many processes, such as the surface energy budget, atmospheric pollution, and boundary-layer parametrization. Most previous studies on stability, however, conducted either theoretical or observational investigations at specific sites, thus leaving a gap with regard to the large-scale pattern. Here, wind speed and temperature observations at multiple heights from the wind-tower network of China are used to estimate the stability during the 2009–2016 period. A series of data-quality-control procedures are conducted and data from 170 wind towers with more than 2 years’ worth of valid observations are selected. The degree of stability is classified by the Obukhov length, which is derived from the wind speed and temperature at 10 m and 70 m above ground level, combined with information regarding the roughness length. Overall, the occurrence frequency of surface-layer instability exhibits significant temporal and spatial variability, being particularly larger in spring and summer than in autumn and winter. The maximum frequency of summertime instability occurs in the time period 1000–1200 local solar time, approximately 2 h earlier than in autumn. Geographically, the peak instability frequency occurs much earlier in the day in north-west China than in other regions, likely owing to the arid and semi-arid land cover. Also noteworthy is the steady increase in instability frequency observed during the period analyzed here, likely resulting from the reduction in the vertical gradient of wind speed. Our findings call for explicit consideration of stability variability in the wind-energy industry and in fundamental boundary-layer investigations in China.
Correlation of volcanic activity and S-wave attenuation anomalies in the Reykjanes Peninsula, Iceland
Authors: Malek Jiri , Fojtikova Lucia ,   NASPMON WP7
Published: February 2023

Increased attenuation of seismic S-waves propagating beneath a volcano is one of the most important seismic indicators of magma or partially melted rocks. We studied the attenuation in the Reykjanes peninsula, Southwest Iceland and its local anomalies in relation to the Fagradalsfjall eruption in March 2021.  The Reykjanes Peninsula (situated on the rift between Eurasian and North American tectonic plates) is characterized by intensive volcanism that forms its unique geological structure and generates seismic swarm activity. Since 2013, it has been monitored by the REYKJANET network. Seismic activity intensified from December 2019 and lasted until the eruption of Fagradalsfjall volcano in March 2021. Seismicity during this period was distributed along the whole peninsula, not only in the vicinity of the eruption site. These data give us a unique opportunity to study the attenuation of seismic S-waves waves and their frequency dependence and to identify anomalies of attenuation.The formula for mean attenuation is derived by estimating maximum seismic amplitudes as a function of earthquake magnitude accounting for hypocentral distance and station constants that reflect local conditions beneath the stations. It was derived for the vertical and horizontal components of S waves using the ground displacement, velocity and acceleration. Significant frequency dependence of attenuation was found with the attenuation coefficient proportional to the logarithm of the frequency. This explains different attenuation of the maximum amplitudes for stronger and weaker earthquakes, which have different prevailing frequencies. It was also found that the attenuation is not homogeneous in the entire area covered by REYKJANET (approximately 35 km x 15 km). The attenuation showed significant changes in time. Strong S-wave attenuation was detected for rays passing through the Krýsuvík volcanic system during the year 2020. This may indicate the presence of partially melted rocks at shallow depth. The attenuation beneath the eruption site at Fagradalsfjall was not anomalous during the year 2020; the anomalous values were only detected at the time of eruption. This study was supported by the NASPMON project.
Tropomi on Sentinel 5 Precursor: 5 Years Data Record of the Atmospheric Composition for Air Quality, Climate and Ozone Layer Monitoring
Authors: Veefkind J. Pepijn , Team the TROPOMI
Published: February 2023

Tropomi (Tropospheric Monitoring Instrument) is the payload on board of the European Copernicus Sentinel 5 Precursor satellite, dedicated to atmospheric composition monitoring. Tropomi is an imaging spectrometer developed by The Netherlands in cooperation with ESA, measuring in the UV, visible, near infrared and shortwave infrared, with a spectral resolution in the range of 0.25 to 0.5 nm. The spatial sampling of Tropomi is approximately 3.5 x 5.5 km2 for most of the bands and 3.5 x 7.0 km2 in the shortwave infrared. The high spatial resolution in combination with the daily global coverage, are key features for the uptake of the Tropomi data for air quality and climate research, as well as for operational applications. The nominal lifetime of the Tropomi mission is 7 years, however there are currently no technical limitations to extent the lifetime many years longer.Tropomi was launched in 2017 and the operational data recors starts in April 2018. All operational data products have recently been reprocessed to provide a 5-year consistent data record. The operational data products include short lived pollutants (NO2, SO2, CO, tropospheric O3 and HCHO), O3 total column and profiles, greenhouse gases (CH4 and tropospheric O3), and cloud and aerosol parameters. Furthermore, there are several research products for additional trace gases (CHOCHO, HONO and OClO), aerosol optical thickness, surface parameters (reflectance and vegetation fluorescence) and ocean color.Tropomi already observed many important events, for example the monitoring of the reduced emissions due to global COVID-19 lockdowns, the discovery of several methane leaks of the oil and gas industry and landfills, the monitoring of the ash cloud of the Hunga Tonga volcanic eruption and the observation of large wildfire plumes from Australia, North and South America, Africa and Siberia.In this contribution we present the current status, achievements and outlook of the Tropomi mission.
Submarine fans in the Kribi-Campo sub-basin, offshore Cameroon: Geomorphology and stratigraphic evolution during the Late Cretaceous
Authors: Secke Bekonga Gouott Boris , Eruteya Ovie Emmanuel , Niyazi Yakufu , Yem Mbida , Yene Atangana Joseph Quentin , Maloh Adolphe Lorcin , Makoube Etame Samuel , Samankassou Elias
Published: February 2023

Submarine fans are deposits of coarse sediments of continental origin in the deep sea, and are generally characterized by a complex depositional architecture, due to the multiple triggering mechanisms of deep-water sediment gravity flows. Consequently, this poses great challenges to deep water petroleum exploration and development. We analyzed the geomorphologic evolution and architecture of Campanian, deeply buried, submarine fans in the Kribi-Campo sub-basin, offshore Cameroon. Using a 3D seismic reflection data set and logs from two wells, we mapped seven horizons, including the fan base, fan top and five internal horizons. In cross-section, the fan is characterized by a high amplitude seismic facies exhibiting an aggradational pattern with parallel and continuous reflectors. The stacked fan-shaped morphology is up to 340 ms TWT thick, extends over an area of 600 km2 and oriented NE-SW, near the Kribi High. The analysis of lobes and channels on each horizon provided a timelapse that captures the major geomorphologic transformations of the submarine fan from its initiation, growth, and abandonment.  The submarine fan is composed of depositional lobes whose beds consist of sand, silt and mud. The detailed structure of these lobes has a finger-like morphology and is generally oriented at high angles to the channel that delivered the sediment to the lobes. The finger-like features are interpreted as thick massive sands, formed as a result of sediment-gravity flows which branched off the main flow eroding into pelagic clay substrate. Two types of channel morphology were identified (straight and sinuous). Our results show that channel and sand-body architecture evolve in a predictive manner, primarily controlled by fan aggradation. The elongated shape and morphology of the submarine fan may arise from the interaction of the fault-related folds and Kribi High, with sandstone deposition within the intervening topographic lows, sourced from the east. The 3D seismic geomorphological analysis of the submarine fan, as presented in this study, is essential to better understand their geometries, facies distribution, stacking patterns and depositional architecture to improve reservoir predictions.
Land-atmosphere coupling in km-scale climate modeling: effects of resolution vs. land-surface model sophistication
Authors: Sangelantoni Lorenzo , Sobolowski Stefan , Ferretti Rossella , Redaelli Gianluca , Ricchi Antonio , Scoccimarro Enrico
Published: February 2023

Recent studies exhibit a considerable reduction of summer season precipitation frequency in the new generation of convection-permitting (CP) climate simulations. This seems to over-correct non-CP wet biases with a knock-on effect on summer temperatures via soil moisture-atmosphere feedbacks. However, it is difficult to elucidate which part of the warmth/dryness in CP simulations can be ascribed to land-atmosphere coupling and/or "atmosphere-only" processes. Another layer of uncertainty belongs to the still crude representation of land surface/sub-surface processes that become especially relevant when approaching such high resolution.In this study we explore the modulation of land-atmosphere coupling when moving from a non-CP to a CP-scale climate modeling, considering increasingly sophisticated land surface model configurations. We perform a two-step dynamical downscaling at ~15 km (convection-parameterized) and ~ 3km (convection-permitting) resolutions with the WRF-4.2.1 regional climate model driven by ECMWF-ERA5 reanalysis. The greater alpine region and the extended summer season (May to September) of 2003 are the spatial and temporal domains of interest. A mini multi-physics ensemble is generated with four Noah-MP land-surface model configurations to examine if, and how, including crucial land processes (e.g., vertical soil water transport) modifies hot-temperature forcing mechanisms in the two resolutions. Moreover, each ensemble member is run according to three different initial soil moisture levels, defining reference, anomalously dry- and wet-initialization experiments.Preliminary results show an improved representation of precipitation statistics (seasonal cumulative, frequency, and 99th percentile) from CP simulations, particularly over complex orography. Generally, maximum temperature reproduction benefits from the CP scale. However, localized warm biases persist over flat terrains regardless of the land surface model configuration. Finally, the two resolutions show a substantially different decay of the initial soil moisture state. At CP scale all three runs converge to similar soil moisture at the end of the integration. Conversely, non-CP runs preserve large soil moisture differences until the end of the summer season, signaling longer soil moisture memory and different soil moisture-precipitation feedback.These factors might significantly affect the reproduction and predictability of environmental and societal relevant hydroclimatic extremes on a wide-ranging temporal scale, from seasonal climate predictions to long-term climate projections.
Tracking and reporting peta-scale data exploitation within the Earth System Grid Federation through the ESGF Data Statistics service
Authors: Nuzzo Alessandra , Antonio Fabrizio , Mirto Maria , Nassisi Paola , Fiore Sandro , Aloisio Giovanni
Published: February 2023

The Earth System Grid Federation (ESGF) is an international collaboration powering most global climate change research and managing the first-ever decentralized repository for handling climate science data, with multiple petabytes of data at dozens of federated sites worldwide. It is recognized as the leading infrastructure for the management and access of large distributed data volumes for climate change research and supports the Coupled Model Intercomparison Project (CMIP) and the Coordinated Regional Climate Downscaling Experiment (CORDEX), whose protocols enable the periodic assessments carried out by the IPCC, the Intergovernmental Panel on Climate Change. As trusted international repository, ESGF hosts and replicates data from a broader range of domains and communities in the Earth sciences leading thus to a strong support to standards for connecting data and application of FAIR data principles to ensure free and open access and interoperability with other similar systems in the Earth Sciences. ESGF includes a specific software component, funded by the H2020 projects IS-ENES2 and IS-ENES3, named ESGF Data Statistics, which takes care of collecting, analyzing, visualizing the data usage metrics and data archive information across the federation. It provides a distributed and scalable software infrastructure responsible for capturing a set of metrics both at single site and federation level. It collects and stores a high volume of heterogeneous metrics, covering coarse and fine grain measures such as downloads and clients statistics, aggregated cross and project-specific download statistics thus offering a more user  oriented perspective of the scientific experiments. This allows providing a strong feedback on how much, how frequently and how intensively the whole federation is exploited by the end-users, as well as the most downloaded data, which somehow captures the level of interest from the community on some specific data. It also gives feedback on the less accessed data, which from one side can help designing larger-scale experiments in the future and on the other hand can help getting some insights on the long tail of research. On top of this, a view of the total amount of data published and available through ESGF offers users the possibility to monitor the status of the data archive of the entire federation. This contribution presents an overview of the Data Statistics capabilities as well as the main results in terms of data analysis and visualization.
Novel selection pressure on plant vascular network as a model of network-mediated hierarchical interactions in the Earth System
Authors: Bouda Martin , Prats Kyra , Huggett Brett , Wason Jay , Wilson Jonathan , Brodersen Craig
Published: February 2023

Hierarchical interactions across scales can drive macroevolutionary change and interactions between biological and physical domains of the Earth system. A recently discovered example is how the evolution of complexity in vascular organisation of plants allowed them to constrain the spread of drought-induced embolism, which played a key role in their ability to colonise dry land and to increase their stature from mere centimetres to tens of metres. This not only reveals a previously unknown process that contributed to the macroevolution of plants and their role in the Earth System, the adaptation of plant vascular organisation can serve as a microcosm model for similarly structured cross-scale interactions.

The earliest vascular plants had developed a central cylinder of water-conducting xylem by the Late Silurian period (∼420mya). This simple form diversified into more complex morphologies as both the size and complexity of the plant body increased during and beyond the Devonian terrestrial radiation. Living plants show a variety of complex vascular forms and both extant plant variety and the fossil record shows a well-known relationship between stem size and vascular complexity. We recently demonstrated a novel selective pressure through drought that favours increased vascular complexity with size through the scaling properties of the conduit network. The topology of the network constrains or facilitates the spread of drought-induced embolism, whose systemic spread is lethal to vascular plants. In essence, network topology integrates the cell-scale properties to plant-scale vulnerability, mediating non-linear cross-scale interactions in vascular plant hydrodynamics.

Topological properties of the conduit network have played a previously underappreciated role in the macroevolution of vascular plants, including in the success of major new taxa as well as in the emergence of novel growth forms over deep time. Moreover, the mathematical properties of these networks and their effects on scaling the biophysical drivers of this selection can be described in a general way that may translate to descriptions of other nonlinear mechanistic cross-scale interactions in the Earth system mediated by network interactions, regardless of physical mechanism and scale.