bluuebunny/crossref_metadata_2025 huggingface dataset:
A 9-YearThee-Dimensional Dust Climatology of the Eastern Mediterranean Basin via CALIPSO-Derived Product
Authors: Aslanoğlu S. Yeşer , Proestakis Emmanouil , Gkikas Antonis , Güllü Gülen , Amiridis Vassilis
Published: February 2023

The Eastern Mediterranean Basin is an intricate transition region between Eurasia and the Middle East along with Alpine-Himalayan orogenic belt. It is almost amidst the dusty belt and a unique hot spot of climate change in the grand picture. As it involves desert source areas, dust-carrying winds to remote downstream locations enable the entire basin to expose particulate matter throughout the year. As well as global oscillation systems, increasing surface temperatures promote uplifted and remotely transported dust particles. In order to clarify this phenomenon, the main aim is to determine the aerosol and, particularly, dust climatology of the Eastern Mediterranean Basin via CALIPSO onboard Lidar CALIOP. This prominent instrument enables us to better understand aerosols, clouds, and their interactions associated with climatic processes. Using the 9-year CALIPSO-derived aerosol-dust dataset, horizontal and vertical distributions, transport heights and case incidences were analyzed. Multi-year climatology results indicated that the dust extinction coefficient, dust mass in the total aerosol bulk, and uplifted heights increased as the location shifted from west to east. Moreover, for dust transport, spring months are more dominant in the western part, while summer and autumn are in the central and eastern parts. Mountain range systems in the Alpine-Himalayan Orogenic belt obstruct the lofted and buoyant particles from reaching higher latitudes in the north. Besides, dust particles prone to accumulate on the southern slopes of the high ridges pose air quality degradation of the distant cities from the dust source areas. In addition to remote cities having ~0.2 peak AOD values, source regions exceed 1.0 aerosol and 0.8 dust optical depth values. The whole basin's ambient air has an average of 40% dust mass in the total aerosol load. From the eastern shores of the Mediterranean Sea, desert areas and particulate matter are more prone to intrude into inner lands with a continental connection. So, south-eastern Anatolia in Turkey reflects the desert levels with approximately a dust load of 70%.
Experimental and Numerical Modeling of Critical submergence for Water Intakes
Authors: Das Bhagwan , Ahmad Zulfequar , Sharma Pramod Kumar
Published: February 2023

A series of experimental and numerical studies were performed to investigate Critical submergence for square water intakes in an open channel flow in this paper. Diversion of water from rivers has recently become a most important subject of study in hydraulic projects, such as water supply, irrigation, power plants, etc. The formation of an air-entraining vortex in the vicinity of an intake is considered to be a severe problem for water intake. The distance between the water surface level and the intake center level is called the submergence of a water intake. Suppose submergence is below a definite lowest level. In that case, air enters into the intake through an air-entraining vortex developing from the free surface, and that specific submergence is termed as critical submergence. Experiments were performed in a concrete flume of 9.47 m long, 0.5 m wide, and 0.6 m deep with an intake of size 0.04 m×0.04 m under uniform approach flow for different flow conditions. A three-dimensional Multiphase CFD Model was also developed for simulating critical submergence for the intakes. Reynolds-averaged Navier–Stokes (RANS) equation with Standard k-ω and SST k-ω turbulence models were used to simulate the fluid flow inside the test domain. These two models, together with the volume of fluid (VOF) two-phase (water-air) model, were found well capable to simulate the flow at critical submergence. Air entraining vortex at critical conditions was identified using phase volume fraction studies and surface streamlines. Multiphase CFD study helped to understand the flow structure and turbulence characteristics of the vortex flow at the vicinity of intakes. The interface between air-water phases has been simulated with better accuracy for identifying the multiphase interface interaction during the event of an air-entraining surface vortex formation. It should be noted that approach flow Froude number and intake flow Froude number play a vital role in observing critical submergence with both experimental and numerical considerations. A comparison of the numerical and experimental results with the selected turbulent model indicated that the multiphase numerical model is capable for simulating flow for air-entraining vortex formation at critical submergence with an 8 % error.
Wind-forced seasonal exchange between marginal seas and the open ocean
Authors: Spall Michael A.
Published: February 2023

The circulation within marginal seas subject to periodic winds, and their exchange with the open ocean, are explored using idealized numerical models and theory. This is motivated by the strong seasonal cycle in winds over the Nordic Seas and the exchange with the subpolar North Atlantic Ocean through the Denmark Strait and Faroe Bank Channel, although the analysis is general in nature and relevant to other marginal seas. Two distinct regimes are identified: an interior with closed 𝑓 /ℎ contours and a shallow shelf region that connects to the open ocean. The interior develops a strong oscillating along-topography circulation with weaker ageostrophic radial flows. The relative importance of the bottom Ekman layer and interior ageostrophic flows depends only on 𝜔ℎ/𝐶d , where 𝜔 is the forcing frequency, ℎ is the bottom depth, and 𝐶d is a linear bottom drag coefficient. The dynamics on the shelf are controlled by the frictional decay of coastal waves over an along-shelf scale 𝐿 = 𝑓0 𝐿s 𝐻s /𝐶d , where 𝑓0 is the Coriolis parameter, and 𝐿s and 𝐻s are the shelf width and depth. For 𝐿 much less than the perimeter of the basin, the surface Ekman transport is provided primarily by overturning within the marginal sea and there is little exchange with the open ocean. For 𝐿 on the order of the basin perimeter or larger, most of the Ekman transport is provided from outside the marginal sea. There is also an opposite exchange through the deep part of the strait, as required to conserve mass within the marginal sea. This demonstrates a direct connection between the dynamics of coastal waves on the shelf and the exchange of deep waters through the strait, some of which is derived from below sill depth.
Assessing the influence of dynamical factors on seasonal skill of severe winter windstorm predictions
Authors: Degenhardt Lisa , Leckebusch Gregor C , Scaife Adam A
Published: February 2023

It is known from previous studies that the winter windstorm season is significantly predictable on a seasonal timescale, especially over the British Isles and southern Scandinavia. Winter windstorms are one of the most damaging extreme events for the European continent. Hence, it is important to know that this skill exists as well as to understand how the forecast model reaches this performance to increase the usability of such forecasts.Here, we link these extreme events to the three most dominant large-scale weather patterns over Europe. A combination of the three leading patterns explains up to 80% of the variability in windstorm frequency and ~60% of storm intensity. A statistical multi-linear model based on these patterns shows similar areas of skill but with lower skill over Europe.This new investigation uses multiple dynamical atmospheric factors known to be related to windstorms, cyclones, their intensification and genesis. Among the factors examined are jet stream strength and location, Rossby wave source, Eady growth rate and potential vorticity. To understand the influence of these factors on windstorm forecast skill, we apply a three step conceptual approach: first to understand the link between windstorms in observations and hindcasts. Second, we analyse the forecast skill of the factors themselves. In the last step we diagnose significant changes in forecast skill of the dynamical factors between well and poorly predicted windstorm years.Factors like MSLP, tropical Atlantic rainfall, jet location, PV in 350K, or Eady Growth Rate all show significant results in individual steps but none of the dynamical factors show significant results in all 3 steps. This could mean that an improved representation of factors and their link to windstorms could improve windstorm seasonal forecast skill.
Aboveground growth responses of mature Picea sitchensis forest stand at different levels of soil warming
Authors: Sigurdsson Bjarni D. , Sigurðsson Páll , Lindau Antonia , Eggertsson Ólafur E.
Published: February 2023

Climate warming is occurring faster in high latitudes and that trend is predicted to continue. How vegetation responds to past warming or to manipulation experiments has proven to be quite site-specific. To better understand the underlying reasons for contrasting responses it is important to study both the direct and the indirect responses to warming that are often mediated through the underlying soil processes.The ForHot site in Iceland offers possibilities to look at the indirect warming effects that are mediated through soil processes. There, a natural soil warming experiment was created in May 2008 by a major earthquake that shifted geothermal bedrock channels to previously cold areas. In this study we use an experimental site with 50-year-old Sitka spruce (Picea sitchensis) and soil warming gradient ranging from 0 to +6 °C between 2008 to 2018. The main objective is to get deeper insights into how rising soil temperatures will affect aboveground growth dynamics in sub-Arctic forest ecosystems.For this paper we used tree-ring analysis of dominant trees from 1988 to 2018, measurements of their height increment from 2000 to 2018, as well as forest stand measurements on permanent inventory plots and litter trap data from 2013 to 2018 and foliar chemical analysis done in 2016.Here we present results on the radial- and height growth before and after the warming was initiated and the consequent changes in tree mortality, stand volume and aboveground primary productivity (ANPP) under different soil warming levels.
Structure and monazite geochronology along the Bavali Shear Zone, the western extension of the Moyar Shear Zone, southern India
Authors: Nanda Saumyaranjan , Rekha Sukumari
Published: February 2023

Bavali Shear Zone (BSZ), the western extension of the Moyar Shear Zone (MSZ), located between the Coorg Block in the north and Nilgiri Block in the south is a 100 km long, steep-dipping and WNW-striking dextral shear zone, which is a less studied part of the MSZ. The majority of the rocks in the BSZ are schistose, including hornblende-biotite±epidote schist, garnet-biotite-sillimanite±muscovite±chlorite schist and talc-tremolite-actinolite-chlorite schist. The gneissic varieties comprise of amphibolite gneiss, granulite gneiss, quartz-feldspar gneiss, hornblende-biotite gneiss, and garnet-biotite gneiss. Other rock types include high-grade metamorphic rocks such as pyroxene granulite and charnockite, banded magnetite quartzite, micaceous quartzite with/without sillimanite, metapyroxenite, amphibolite and mylonite. Several felsic intrusive like granite, diorite, syenite, quartz-feldspar leucosomes and mafic/ultramafic intrusive such as gabbro and anorthosite are found in some places.The dominant structural trend of the BSZ is WNW with strikes varying between 110⁰N and 130⁰N. The steep-dipping and variably oriented pre-shear zone fabrics are preserved in low-strain domains. The BSZ is steep dipping and characterized by steeply-plunging stretching lineation with a persistent dextral sense of shear. The shear zone shows N-down kinematics in vertical sections perpendicular to the shear zone fabrics. The β-axis of poles to the shear zone fabric and the orientations of the hinges of the folds related to shearing share low-angle obliquities with the stretching lineations. It indicates that the shear-related folds have a reclined to steeply-inclined geometry, and the fold hinges are broadly collinear with the stretching direction. The last deformation in the BSZ with down-dip stretching lineation clearly shows the features of the transpressional shear zone with a dextral sense of movement and top-to-the-north kinematics.U-Th-(total) Pb monazite chemical dating was performed on structurally constrained monazites from the BSZ. Monazites from one garnet-biotite-sillimanite-chlorite schist, one garnet-biotite gneiss and one mylonite close to the BSZ were dated. The monazite hosted in the garnet-biotite-sillimanite-chlorite schists provide prominent ages of 751±40 Ma, the garnet-biotite gneiss yielded a peak at 742±15 Ma and the single mylonite sample collected close to the BSZ yield a distinct age peak at 745±67 Ma. All the metamorphic monazites from the BSZ show a prominent mid-Neoproterozoic age, lacking in the adjoining Coorg Block, Nilgiri Block and Western Dharwar Craton. We, therefore, assign this mid-Neoproterozoic metamorphic chemical ages retrieved from monazites to the ductile deformation in the BSZ that reoriented all the pre-shearing fabrics and speculate that the BSZ collision orogeny preceded the eventual integration of the Greater India landmass with the Gondwanaland during the early-Palaeozoic.
Assessment of flooding impact on water supply systems: a comprehensive approach based on DSS
Authors: Bonaccorsi Bianca , Barbetta Silvia , Tsitsifli Stavroula , Boljat Ivana , Argiris Papakonstantinou , Lukač Reberski Jasmina , Massari Christian , Romano Emanuele
Published: February 2023

The assessment of flood impact on a Water Supply System (WSS) requires a comprehensive approach including several scales of analysis and models and should be managed in the Water Safety Plans (WSP), as recommended in the EU Water Directive 2020/2184. Flooding can affect the quality of groundwater and surface water resources and can cause supply service interruption due to damaged infrastructures. A complete approach to address flood impact on WSS is required but is not yet available, while only specific aspects were investigated in details.In this context, the MUHA project, funded by the European INTERREG V-B Adriatic-Ionian ADRION Programme 2014-2020, developed a comprehensive tool named WAter Safety Planning Procedures Decision Support System (WASPP–DSS). The tool is mainly addressed to small water utilities (WU) for supporting WSP development and is based on two main premises: 1) a correct approach for WSS risk analysis requires a multi-hazard perspective encompassing all the system components and different hazards; 2) other institutions in addition to WUs have to be involved in WSS risk analyses to harmonize monitoring and response procedures.The tool was tested on six pilot areas of the ADRION region considering four hazards: drought, flooding, accidental pollution and damage to infrastructure due to earthquakes. In this work, the tool is demonstrated for flooding impact analysis in three pilot areas: the Ridracoli reservoir in Italy and two municipalities, Larissa in Greece and Zadar in Croatia. The WASPP–DSS, tested by eight WUs, was found a potentially valid support for small WUs that must start drafting the WSP in a comprehensive way and can provide a common shared scheme.Improvements are desirable, as including a specific section to consider the issue of loss of water resources from reservoirs due to overflow.
Convolution Neural Network (CNN) Approach for Classification of Diseased and Healthy Paddy Crop using UAV-based Multispectral Imageries
Authors: Biswal Sudarsan , Chatterjee Chandranath , Mailapalli Damodhara Rao
Published: February 2023

The conventional way to detect plant defects is tedious and inefficient through human vision. It requires deep knowledge gained through years of experience, ground observations and understanding of the plant. Therefore, the intelligent methods in this research are expected to assist the farmers in identifying whether a region is disease-affected or healthy. The proposed study aims at the image processing technologies for disease identification using different band images acquired through Unmanned Aerial Vehicle (UAV) mounted with a multispectral camera in the paddy domain. The multispectral imageries were obtained at 30 m altitude to detect diseases in a paddy cultivar (MTU1010) affected by grain discolouration disease. The deep learning method of Convolution Neural Network (CNN) with VGG 16 architect was proposed to classify healthy and diseased images. In the image classification process, the following combinations such as (NIR, RED, NDVI) or (NIR, RED_EDGE, NDVI) or (NIR, RED, NDRE) or (NIR, RED_EDGE, NDRE) were used to identify whether an image is healthy or diseased depending upon their training accuracy, validation accuracy, precision, recall, F1 score and Kappa coefficient. The results showed that the combination of (NIR, red, NDVI) and (NIR, red, NDRE) gives the best classification for diseased and healthy identification. The proposed method is expected to reduce the risk of disease spread over the entire field, which may increase the paddy yield.Keywords: Disease classification, CNN, NDVI, Multispectral imageries, UAV
Making use of multi-sensor satellite imagery for oil spill observation and oil drift monitoring
Authors: La Tran Vu , Pelich Ramona-Maria , Chini Marco , Li Yu , Matgen Patrick
Published: February 2023

Over the last ten years, satellite imagery has become one of the most effective means to observe offshore oil spills, especially over a large area, thanks to their high spatial resolution and wide swath coverage. In particular, the use of images acquired by multi-sensors, including Synthetic Aperture Radar (SAR), optical, and visible/near-infrared, allows not only to early and quickly detect oil spills but also to monitor oil drift in short-terms (several hours) and long-terms (one or two days). Such approach has not been assessed in-depth in previous studies probably due to the lack of satellite data. A case study was presented in [1] to observe the movement of oil slicks through the combination of data acquired by SAR satellites, SAR airborne system, optical instrument, and in-situ observations. However, it is very complicated to implement such method for the other cases of oil spills since it requires many different platforms and sensors that are not systematically available. Therefore, this paper focuses uniquely on the collocation of sequential images acquired by various satellite sensors (SAR and optical) for oil drift monitoring in short-terms (several hours) and long-terms (up to 24–36 hours).For instance, to observe oil spills caused by a wrecked ship offshore Corsica (France) in Oct. 2018, we combine the images acquired by Sentinel-1 SAR (Oct. 8, 2018, 05:27:57 UTC, 17:21:45 UTC; Oct. 9, 2018, 17:14:27 UTC), Sentinel-2 optical sensor (Oct. 9, 2018, 10:20:21 UTC), and Radarsat-2 SAR (Oct. 9, 2018, 04:04:15 UTC). The techniques of oil spill detection from SAR and optical images are different. They are based on an advanced image processing procedure that will be presented at the conference. Due to the time lags between these images, we can estimate the movement of the detected oil slicks in terms of distance, velocity, and direction for 6, 12, 24, 36 hours of observation. Finally, we compare the oil drift results with the hourly data of met-ocean variables (surface wind and current) to assess the impact of the latter on oil drift. Surface wind fields (0.25° × 0.25° grid) and current vectors (0.083° × 0.083° grid) are extracted from the ERA-5 [2] and CMEMS [3] reanalysis data, respectively.[1] C. Brekke, M. M. Espeseth, K.-F. Dagestad, J. Röhrs, L. R. Hole, and A. Reigber, “Integrated analysis of multisensor datasets and oil drift simulations—a free-floating oil experiment in the open ocean,” J. of Geophysical Research: Oceans, vol. 126, e2020JC016499, 2021, doi: 10.1029/2020JC016499.[2] H. Hersbach et al., “ERA5 hourly data on single levels from 1959 to present,” Copernicus Climate Change Service (C3S) Climate Data Store (CDS). (Accessed on <05-12-2022>), 10.24381/cds.adbb2d47, 2018.[3] Global Ocean 1/12° Physics Analysis and Forecast updated Daily (Accessed on <05-12-2022>), doi: 10.48670/moi-00016.
Neolithic Agronomists shaped Chernozem in South-Eastern Bavaria
Authors: Völkel, Prof. Dr. Jörg , Holmer Anna Sophia , Bösze Ildikó , Moosbauer, Prof. Dr. Günther
Published: February 2023

Up to today, the reason for the genesis of chernic horizons in Germany is a matter of discussion. Recent literature is strongly suggesting a purposeful anthropogenic soil management from neolithic times as an origin of these soils. Here we provide another example of neolithic activities meliorating the soil from a calcic Luvisol to a Chernozem with a dimension of several hectares. This is striking, since it is the first finding of a chernic horizon of this extensiveness in Bavaria, Germany.The Chernozem has been discovered close to the city of Straubing (48°53′N, 12°34′O, MAP 757 mm, MAT 8,6°C), which is situated in the highly arable Danubian Gäuboden and part of the so called Altsiedelland. It has been home to human settlers ever since the first settlers belonging to the Linearbandkeramik (LBK) culture immigrated, among other things like the optimal climatic conditions due to its very favorable soil characteristics (luvisols) developed on Loess. The neolithic Chernozem is located directly next to a graveyard with graves dating in early neolithic times and later as well as neolithic settlements 500 m away. Collected 14C and OSL-data strongly suggest that part of the Chernozem was covered by a roman colluvium probably eroded from the former graveyard hill by roman ploughing activities. Our obtained 14C data places the chernic horizon itself into the early LBK and onwards. Nowadays the chernic horizon is mostly overprinted by the ongoing soil genesis as an argic horizon. Small charcoal flakes (< 0.5 mm) make the chernic horizon appear greyish-black up to today, with carbon-contents of around 1%. The colour intensifies in the center of the Chernozem area closely by the settlements and graveyard and fades out to a distinct grey shadow in the argic horizon of the calcic luvisol above around 2 km away.These findings leave no room for doubt: The Chernozem has an anthropogenic origin and was created by the neolithic settlers, following a purpose in managing and meliorating the soil.
Ensemble sensitivity localization
Authors: Griewank Philipp Johannes , Necker Tobias , Weissmann Martin
Published: February 2023

Ensemble sensitivity is a tool to quantitatively determine which initial conditions influence a forecast quantity of choice. This information can then be used to understand the sources and dynamics of forecast uncertainty, quantify the impact of observations (e.g., E-FSOI), and determine where to best deploy observations to improve the forecast (e.g., observation targetting and network design). The ensemble sensitivity is calculated from the covariances of the initial ensemble to the forecast ensemble. Unfortunately, these covariances are prone to sampling errors due to the limited ensemble size. The most common approach in data assimilation to mitigate sampling errors is to apply distance-based damping, i.e., localization. This poster explores how to localize the sensitivity correctly and how it differs from analysis localization. Using simplified problems, we highlight the benefits and drawbacks of sensitivity localization and discuss its usefulness to numerical weather prediction applications.
The Role of Aged Organic Carbon in North Atlantic Fjord Sediments
Authors: Smeaton Craig , Haghipour Negar , Austin William , Eglington Timothy
Published: February 2023

Fjords are recognised as important hotspots for the burial and storage of organic carbon (OC) within their sediment, which potentially provides a long-term climate regulation service. Annually, it is estimated that 18 Mt of OC is buried within fjord sediments with between 55 – 62% of the OC originating from the terrestrial environment. The transfer of OC from the terrestrial environment to the fjord sediments is likely a significant pathway for aged OC to reach the coastal ocean. By estimating the quantity and mapping the spatial distribution of aged OC within the fjord sediments, we can develop a better understanding of the processes that govern the transfer of terrestrial OC from the catchment to the sediment of fjords, further constraining their role in long-term climate regulation.Here we bring together radiocarbon analysis with isotopic and biomarker measurements to investigate the age of the surficial sediments within 46 fjords across the North Atlantic. The fjords in this study range from Scottish systems with catchments dominant with OC rich peat to the glaciated systems of Svalbard and Greenland.  The results from this analysis highlight that a multiple natural and anthropogenic processes govern the quantity and distribution of aged OC across North Atlantic fjords ranging between glacial input of fossil OC to the erosion of aged terrestrial material facilitated by deforestation.  This study highlights the fundamental need to understand the processes that govern the transfer of OC across the land-ocean interface to allow the role these marine sedimentary systems play in long-term climate regulation to be constrained.    
A temporal graph to predict chemical transformations in complex dissolved organic matter
Authors: Lechtenfeld Oliver , Plamper Philipp , Herzsprung Peter , Groß Anika
Published: February 2023

Dissolved organic matter (DOM) is a complex mixture of thousands of natural molecules that undergo constant transformation in the environment, such as sunlight induced, photochemical reactions. Despite molecular level resolution obtained by ultra-high resolution mass spectrometry, the mechanistic understanding of DOM transformations is still hampered due to a multitude of simultaneous reactions. Temporal trends of mass peak intensities are currently the only way to follow photochemical induced molecular changes in DOM, but are often limited by low temporal resolution or the necessity to apply monotonic regression models. Here, we present a novel computational approach using a temporal graph (a temporal molecular network) to model the transformation of DOM molecules in a photolysis experiment by employing a predefined set of basic molecular transformation units (like oxidation, decarboxylation, etc.). The new algorithm focuses on the temporal changes of mass peak intensities of molecular formulas by simultaneously considering educt removal and product formation for molecules linked by a transformation unit (e.g. -CO2). The transformations and molecules are further weighted by the extent of intensity change and grouped by unsupervised machine learning algorithms to find clusters of similar reactivity. The temporal graph thus allows to simultaneously identify relevant molecules subject to similar reactions and to study their time course. The graph can be constructed for low and high temporal resolution data without presumptions on reaction kinetics and with different sets of transformation units according to the experimental design. Our approach overcomes previous data evaluation limitations for mechanistic studies of DOM transformation and leverages the potential of temporal graphs to study the reactivity of complex DOM by means of ultra-high resolution mass spectrometry.
Estimate of Critical Thresholds with Variance and Parabolic Approximations
Authors: Cotronei Alessandro , Rypdal Martin
Published: February 2023

It is wide scientific consensus that tipping points, in the form of rapid, large and irreversible changes in features of the climate system, are a possible scenario consequent to anthropogenic climate change. In literature there are several ways to detect the so-called Early-Warning-Signals, indicators (as increasing variance) that these changes are close to our current state and that the climate state is about to shift. We propose two novel indicators based on variance and parabolic approximations that expand the current theory to detect these EWSs. We show that the methods can produce estimations for the critical thresholds for particular systems. We finally show that our indicators predict close thresholds for the loss of ice of the Greenland ice sheet.
Variations of high time resolution heavy ion characteristics in the complex May 2005 ICME
Authors: Gu Chaoran , Heidrich-Meisner Verena , Wimmer-Schweingruber Robert F.
Published: February 2023

Coronal Mass Ejections~(CMEs) are extremely dynamical large scale events in which plasma-not only the coronal plasma-is ejected into the interplanetary space. Their interplanetary counterparts measured in-situ are Interplanetary Coronal Mass Ejections (ICMEs), which is also an important part of space weather.Even though the kinetic properties of the plasma might change because of dynamic effects occurring during the expansion of the CME, the heavy ion characteristics remain unchanged after it leaves the low corona. Charge states of heavy ions reflect important information about the coronal temperature profile due to the freeze-in effect, while elemental abundances indicate potential source regions of the plasma.With the help of the Pulse Height Analysis (PHA) data from the Solar Wind Ion Composition Spectromet (SWICS) on board the Advanced Composition Explorer (ACE), combined with a newly developed multi-population model, we are able to conduct a high time resolution (12 minutes) case study on a complex ejecta detected by ACE in May 2005. This case lasted more than 80 hours and caused a strong geomagnetic response, with a Dst index at -247.Multiple discontinuous periods with highly charged heavy ions are identified, elemental abundances also differ during those ”hot” periods. Heavy ion characteristics provide us an unique opportunity to see the boundaries of different parts of an ICME.
Urban Sustainability in Action - Multi-disciplinary Approach through Jointly Organised Research Schools (URSA MAJOR)
Authors: Turton Jenny , Ezau Igor , Pettersson Lasse , Kuklina Vera , Temeljotov-Salaj Alenka , Abbas Petersen Sobah
Published: February 2023

Smart cities, sustainable and resilient urban centres, are now being designed and implemented all over the world – including in the Arctic. They are a major part of the European Union's Green Deal transformation and the Sustainable Development Goal (SDG) 11 (sustainable cities and communities), but opinions of those living in such cities can be divided. Additionally, most Smart City frameworks have focused on technological advances and have excluded climate change and environmental aspects. The URSA MAJOR project targets education and science communication to future urban stakeholders, such as civil engineers, ecologists, urban architects, city managers and administrators. The holistic educational approach includes digitalising, collecting, storing and analysis of social and environmental information, visualising in different ways through digital technology, and education and training to use the data.Aspects of the project include eLearning opportunities, urban modelling, citizen science, use of open available data and climate change education. The educational aspects are focused on university students, but the local communities in four cities, as well as Arctic stakeholders are also part of the scope. This presentation will focus on the four main working packages of the project, the needs of an interdisciplinary project team and the results of the science communication efforts, which are now two years in.
Atmospheric ammonia in-situ long-term monitoring: review worldwide strategies and recommendations for implementation
Authors: Bourin Aude , Espina-Martin Pablo , Font Anna , Crunaire Sabine , Sauvage Stéphane
Published: February 2023

Ammonia (NH3) is the major alkaline gas in the atmosphere and the third most abundant N-containing species, after N2 and N2O. It plays an important role in N deposition processes, responsible of several damages on ecosystems, and it is also a precursor of fine particulate matter, known to cause numerous impacts on human health. Despite this, not many countries have implemented long-term monitoring of NH3 in their air quality programs due to the lack of consensus on limit values for ambient levels and a reference method of measuring this gas. In the climate change context, governments and health organizations are increasingly concerned about NH3 and its effects. As a proof, the revision of the EU air quality directives proposes the inclusion of NH3 as a mandatory pollutant for several urban and rural supersites for all member states.Currently, there are only 12 long term programs worldwide dedicated specifically to measure NH3 or including gas-phase measurements of NH3. The longest NH3 time series come from UK and Africa, where measurements start in mid-1990. The rest of locations have started after 2000 and they have lower temporal coverage, between 5 and 22 years. The objectives pursued by these networks are to follow long term spatio-temporal trends, assess the N deposition on sensitive ecosystems, validate emission and/or chemistry transport models and help to understand the effectiveness of air pollution control and mitigation policies. Most of these networks operate using a combination of low-cost samplers with a high spatial density with few collocated sites with high time resolution instrumentation to help calibrate passive samplers and to better monitor the fine temporal variability of NH3. This combined approach has proven to be successful for most of the proposed objectives.However, there are several differences that may difficult harmonizing the information at both the technical and scientific level. At the technical level these include type and number of passive samplers per site, calibration protocol, data control and quality analysis, exposure duration and type of high time resolution sampling method. On the scientific level, increased difficulty understanding the operative parameters and scientific results may come from language barriers (non-English reports), availability of the data (whether it is public or not), and gaps on the knowledge of NH3 levels on a spatial scale due to differences in the implementation of monitoring strategies within the same country.This work aims to review synthetically the world current long-term NH3 networks and provide some insight and recommendations for other countries and supranational programs aiming to establish long term monitoring networks of NH3, based on cost-effective, technical, and operational criteria.
Analysis of the organization in place to manage flood resilience in Tahiti urban area (French Polynesia), as a framework for risk observatory
Authors: Bourlier Bastien , Heinzlef Charlotte , Taillandier Franck , Curt Corinne , Serre Damien
Published: February 2023

There are real needs to innovate in risk management approaches to address issues of vulnerable territories such as French overseas territories identified as particularly exposed to natural hazards. This communication focusses on the Tahiti urban environment in French Polynesia, a dense urban area, subject to coastal and river flooding hazards. French Polynesia is a semi-autonomous territory with a specific institutional context. The distribution of competences, the main development perspectives, or the management plans are specific to this territory. In addition, significant gaps and weaknesses in risk management have been identified in a governmental report in 2018 (isolation, lack of management plans). Our objective is to define the conditions for a resilient territorial organization for flood risk management, to highlight structure, issues and weaknesses.The method is based on a qualitative analysis of the current organization for the management of flood in Tahiti. For this purpose, we interviewed fifteen local actors in charge of flood risk management on the urban area (semi-directive interviews of about 45min). These actors belong to the different territorial levels (municipality, country and state). The aim was to collect information about their intervention capacity, the spatial inequalities of these interventions, but also the processes of communication and exchange between actors as well as questions inherent to competences share and local governance autonomy.The results highlight more precisely the gaps in risk management, better identify the specificities of the actions articulations, and finally to suggest ways of fostering the resilience of organizations. More precisely, they highlight the concentration of resources for crisis management phases, while other activities, such as prevention and urban planning, remain largely undeveloped. This research also emphasizes the adaptation capacities of the territory by solidarity processes and the existence of a significant risk culture. Furthermore, this study makes it possible to establish a framework, identify strengths and weaknesses as well as the role and methods of each stakeholder. Taking into consideration the bicephalous dimension of local governance (between French Polynesia and the French state) is a major issue implying the improvement of coordination and consultation processes.This approach provides a comprehensive view of the territory's organization to flood management and allows us to frame the operational conditions for the implementation of a resilience observatory helping long-term thinking and collaboration and, consequently, improving the effectiveness of the processes in place. This observatory will facilitate sharing and co-construction of data, cooperation, and also communication with decision makers.
Early greenup impact on seasonal streamflow and soil moisture dynamics in humid, temperate forests
Authors: Hwang Taehee , Band Lawrence , Oishi Christopher , Kang Hojeong
Published: February 2023

Ongoing warming due to climate change has generally led to lengthened growing seasons and subsequent changes in evapotranspiration (ET) and streamflow seasonality. This has been well studied in seasonally dry, snowmelt dominated watersheds, but not in humid, temperate forested watersheds without significant seasonal snowmelt. In this study, we investigate how seasonal streamflow patterns have responded to variability in vegetation phenology in the southern Appalachians over the last four decades. We characterize seasonal shifts in low-frequency streamflow peaks using 50th percentiles of cumulative daily precipitation, streamflow, and soil moisture measurements, and investigate interactions with remotely sensed, long-term greenup anomalies in the deciduous-dominated forested watersheds. After removing a dominant precipitation control, one-day earlier greenup is associated with about one-day early spring flow peak at the low-elevation deciduous catchment. This indicates that the strong dependency of seasonal flow regimes on precipitation is mediated by warming-induced extended growing season, especially by early greenup. In contrast, we find less significant correlations of the greenup anomalies on flow percentiles of an adjacent evergreen and a high-elevation deciduous catchment. At a plot scale, similar correlations of cumulative soil moisture days were found only at an upslope topographic position, where precipitation also showed tighter coupling with soil moisture patterns than downslope. This indicates that early greenup in deciduous forests leading to early ET increase, in turn results in early soil moisture dry-down patterned by hillslope positions, and earlier seasonal streamflow peaks and subsequent declines. Our study suggests that spring flow peaks are likely to shift earlier by warming-induced early greenup even in snow-free regions, which has great implications for future freshwater availability in the southeastern US.
Deforestation alters dissolved organic carbon and sulfate dynamics in a mountainous head water catchment—A wavelet analysis
Authors: Wang Qiqi , Qu Yuquan , Robinson Kerri-Leigh , Bogena Heye , Graf Alexander , Vereecken Harry , Tietema Albert , Bol Roland
Published: February 2023

Deforestation has a wide range of effects on hydrological and geochemical processes. Dissolved organic carbon (DOC) dynamics, a sensitive environmental change indicator, is expected to be affected by deforestation, with changes in atmospheric sulfur (S) deposition compounding this. However, how precisely anthropogenic disturbance (deforestation) under a declining atmospheric S input scenario affects the underlying spatiotemporal dynamics and relationships of river DOC and sulfate with hydro-climatological variables e.g., stream water temperature, runoff, pH, total dissolved iron (Fetot), and calcium (Ca2+) remains unclear. We, therefore, examined this issue within the TERENO Wüstebach catchment (Eifel, Germany), where partial deforestation had taken place in 2013. Wavelet transform coherence (WTC) analysis was applied based on a 10-year time series (2010–2020) from three sampling stations, whose (sub) catchment areas have different proportions of deforested area (W10: 31%, W14: 25%, W17: 3%). We found that water temperature and DOC, sulfate, and Fetot concentrations showed distinct seasonal patterns, with DOC averaging concentrations ranging from 2.23 (W17) to 4.56 (W10) mg L-1 and sulfate concentration ranging from 8.04 (W10) to 10.58 (W17) mg L-1. After clear-cut, DOC significantly increased by 59, 58% in the mainstream (W10, W14), but only 26% in the reference stream. WTC results indicated that DOC was negatively correlated with runoff and sulfate, but positively correlated with temperature, Ca2+, and Fetot. The negative correlation between DOC with runoff and sulfate was apparent over the whole examined 10-year period in W17 but did end in W10 and W14 after the deforestation. Sulfate was highly correlated with stream water temperature, runoff, and Fetot in W10 and W14 and with a longer lag time than W17. Additionally, pH was stronger correlated (higher R2) with sulfate and DOC in W17 than in W10 and W14. In conclusion, WTC analysis indicates that within this low mountainous forest catchment deforestation levels over 25% (W10 and W14) affected the coupling of S and C cycling substantially more strongly than “natural” environmental changes as observed in W17.
The opportunity cost of land use restrictions and their impact on the energy transition - a case study for Germany´s onshore wind power
Authors: Tafarte Philip , Geiger Charlotte , Lehmann Paul
Published: February 2023

Wind power onshore is one of the key technologies in the process of transitioning to a climate-neutral energy system. Yet, negative externalities of wind power for people and nature can occur. These externalities are usually regulated with spatial planning instruments that exclude certain areas from wind power development, like forest bans or increased setback distances to settlements, which were introduced across many regions in recent years. However, this regulatory practice can cause trade-offs between the regulated externalities. We use a multi-criteria GIS-based model of the potential areas for wind power onshore in Germany to identify and quantify these trade-offs for forest bans and setback distances to settlements.  Our results show that relevant trade-offs exist between a forest ban and the proximity of the remaining potential areas to settlements as well as between setback distances and the share of forest in the remaining potential area. Further, we find that individual and simultaneous implementations of the described regulations reduce the potential area of and production potential from wind power to an extent that future expansion targets for onshore wind power in Germany are no longer achievable.
Early Triassic hothouse conditions limited marine productivity
Authors: Grasby Stephen
Published: February 2023

The Early Triassic represents a period of prolonged recovery following the most severe extinction of the Phanerozoic. Records show this to be a period of extremely high global temperatures, likely driven by Siberian Traps eruption induced global warming. How this hothouse impacted marine ecosystems and prolonged the recovery process remains uncertain. Across northwestern Pangea, Early Triassic marine sediments are characterized by low organic matter content, despite recurrent anoxia which would create conditions more suitable for preservation, and being located on the western continental margins were the majority of primary productivity in the Panthalassa Ocean would occur. Geochemical proxies suggest the paucity of organic matter reflects a productivity collapse rather than changes in preservation. Nitrogen isotopes show a progressive negative shift starting at the Permian/Triassic extinction and continuing through to the Smithian, indicating progressively growing nutrient limitation. High ocean temperatures likely deepened the thermocline, limiting nutrient recycling and upwelling into the photic zone driving nutrient stress. Finally ocean cooling in the Anisian is marked by widespread deposition of organic rich black shales and return of N isotopes to values consistent with active nutrient upwelling. A hyperthermal driven nutrient-limited Early Triassic ocean was likely a key inhibiter of marine recovery.
Early onshore basaltic alteration and its natural hydrogen potential in the Asal–Ghoubbet rift, Republic of Djibouti.
Authors: Pasquet Gabriel , Duttine Mathieu , Moretti Isabelle
Published: February 2023

The East African Rift (EAR) is a large opening system that allows the observation of all stages of rift evolution from continental opening in the south to oceanization in the north (Ethiopia-Djibouti). Also, the Asal–Ghoubbet active rift, in the Republic of Djibouti, is composed of a magmatic crust and tends to evolve into an oceanic crust. It’s a site of interest for geothermal energy and natural hydrogen. Previous studies have indicated that dihydrogen (H2) emanates from this rift. However, the well-known serpentinization reaction is not the mechanism generating H2 at this site. Rather, the H2 is generated as follows: (1) by alteration of basaltic lava at depth via reaction with seawater flowing from Ghoubbet Bay towards Lake Asal; (2) by simple degassing of the volcanic chamber located a few kilometers below the Fiale Caldera in the rift axis; or (3) as a result of pyritization processes via the oxidation of H2S.Drill cuttings from the Fiale 1 (F1) and Gale le Goma 1 (Glc1) geothermal wells (located on the inner and outer rift margins, respectively) were analyzed to determine where H2 is generated. Total rock analyses indicated distinct zones at depths of 464 m and 280 m for F1 and Glc1, respectively, representing the boundary between the Asal and Stratoïd Basalts. 57Fe Mössbauer analyses show a decrease in the percentage of Fe3+ at depth, indicating that Fe2+-rich material, particularly in the Stratoïd Basalts, may be a source of H2.Based on well data from the rift center and the outer rift margin, it is evident that H2 is present at the surface in the rift axis and that this area offers good remnant potential because of the presence of Fe-rich chlorite. Conversely, few H2 emissions were measured at the surface on the outer rift margins, although well data showed some H2 (~0.25%) at depth. The presence of a cap rock in the rift axis has not yet been proven; however, the high loss on ignition and the mineralogy in well Glc1 may indicate that the rocks are sufficiently altered to offer potential as a seal. If so, the rift margins would offer greater exploration potential than the rift center.