bluuebunny/crossref_metadata_2025 huggingface dataset:
Using mutual information to investigate non-linear correlation between AE index, ULF Pc5 wave activity and electron precipitation
Authors: Hoilijoki Sanni , Kilpua Emilia , Osmane Adnane , Kalliokoski Milla , George Harriet , Savola Mikko , Asikainen Timo
Published: March 2022

The Earth’s radiation belts are occupied by energetic electrons trapped by the geomagnetic field. The anisotropic electron distribution injected from the magnetotail during substorms drives the very low frequency whistler mode chorus waves in the outer radiation belt. Chorus waves are able to accelerate the electrons as well as cause them to precipitate into the upper atmosphere. The electrons in the radiation belt are also affected by ultra-low frequency (ULF) waves in the Pc5 range, that can be driven internally or by the solar wind-magnetosphere interactions. Using mutual information from information theory, we investigate the nonlinear dependence between the substorm activity indicated by the AE index, global Pc5 ULF wave activity, and electron precipitation at three different energy ranges between L shells from 5 to 7. We find that both the Pearson correlation and mutual information are highest between the AE index and precipitation of 30-100 keV energy electrons between MLTs 6-12, where the electrons are usually precipitated by the chorus waves. The time lag of the maximum correlation between the AE index and electron precipitation increases from 0 to 3h from dawn to dusk, which is consistent with drift period of the electrons in the radiation belt. We compare results from geomagnetically more and less active years and the results indicate that Pearson correlation between AE index and ULF wave activity/electron precipitation is weaker during the more active year while the changes in the mutual information are negligible. This suggest that during quieter magnetospheric conditions the interactions are more linear than during geomagnetically active times.
A new instrument for in-situ HONO measurements by Iterative Cavity enhanced DOAS
Authors: Lampel Johannes , Pöhler Johannes , Horbanski Martin , Platt Ulrich
Published: March 2022

We present a new spectroscopic instrument to measure directly ambient in-situ HONO (nitrous acid) concentrations using the ICAD technique. HONO concentrations can be measured with an error of 400 ppt at 10s and 90 ppt at 1h time resolution. The advantage of the ICAD spectroscopic technique is that it does not require gas calibration and allows for simple long term operation with  high accuracy while not relying on the absolute stability of the light source intensity.

Atmospheric HONO concentrations are of interest since they significantly influence OH radical concentration and thus the tropospheric oxidation capacity. Also, HONO can give rise to the formation of highly mutagenic species in the human lung. HONO sources are still largely unknown in detail and discrepancies are observed between measured and modelled HONO concentrations. We present in-door and out-door in-situ observations of HONO and long-term stability tests.

The instrument provides simultaneous measurements of NO2 with a measurement error of 600 ppt at 10s time resolution and 140 ppt at 1h time resolution (based on modified Allan deviation). With an overall power consumption of typically 40W, its robustness to vibrations and a 19” Rack housing size of 13,5 x 49 x 61 cm³, it is also suitable for mobile applications as is the commercially available NO2/NOX version of the instrument.
Developing a methodology for the delineation of regions into landslide domains with a case study in East Sikkim, India
Authors: Heijenk Renée A. , Dashwood Claire , Taylor Faith E. , Wood Joanne L. , Arnhardt Christian , Malamud Bruce D.
Published: March 2022

Here we present a methodology for the mapping of landslide domains, using as a case study East Sikkim district (964 km2, population of 283,583 in 2011), a landslide-prone region in northeast India. Landslide domains are defined as regions with similar physical and environmental characteristics that specifically drive landslide dynamics. The methodology given here is more systematic than what has previously been used and draws on information on landslide factors inferred from landscape variables. Commonly used landslide factors are divided into three groups: preconditioning, preparatory, and triggering factors. Elevation data, geology, and landslide inventory information are used to provide information on the landslide factors in the study region. Data from the neighbouring and geologically similar regions of East Sikkim district are used to enhance landslide inventory information in the study region, effectively doubling the number of landslides in the inventory from 210 to 440 mapped landslides. We iterate over each of the landslide factor groups and for each iteration either map a new landslide domain boundary or enrich the information of the landslide domains. As a result, we map four landslide domains in East Sikkim district, India, with a size ranging from 81 km2 to 394 km2. The domains have been further enriched using information on rainfall and earthquakes. Each landslide domain describes the typology of landslides and the general geomorphology and land use. The landslide domains in East Sikkim district can be used for (i) describing landslide processes homogenously; (ii) illustrating landslide processes for training or stakeholder engagement; and (iii) as a starting point for the construction of landslide susceptibility maps and landslide early warning that actively draws from the landslide processes that can be found in the region.
Impact of climate change on bioclimatic zoning of chestnut trees in Portugal
Authors: Freitas Teresa Raquel , Santos João A. , Silva Ana P. , Fraga Hélder
Published: March 2022

Chestnut tree cultivation is largely spread worldwide, with approximately 596 × 103 ha devoted to fruit production, raising global production to approximately 2.5 million t, with an upward trend of 56 × 103 t per year. In the European Union, Portugal is the largest chestnut producer (38,870 ha). In  ecent years, the country has shown an increasing trend of 723 ha per year, and the production was 35,830 t in 2019, but largely concentrated in the northeast. In the present study, bioclimatic indices are applied to analyse the spatial distribution of chestnut trees in mainland Portugal, namely degree days (suitability interval: 1900–2400ºD), annual mean temperature (8–15ºC), monthly mean maximum temperature <32ºC, and annual precipitation (600–1600 mm). These indices are assessed for both historical (1989–2005, from IBERIA01) and future (from EURO-CORDEX) climates, within three sub periods: 2021–2041, 2041–2060, and 2061–2080, and under two anthropogenic radiative forcing pathways (RCP4.5 and RCP8.5). For the historical period, in terms of degree days, the suitability for chestnut tree cultivation (i.e., percentage of years fulfilling the predefined interval) is 10% in southern Portugal, whereas much higher values are found at high elevations in the north (50–90%). For the annual mean temperature, most of northern Portugal shows almost 100% suitability. Concerning the maximum temperature, the suitability reduces from the west (100–90%) to the east (40%). Regarding the annual precipitation, the suitability is heterogeneous throughout the territory, with areas under 50%. A compound index is also defined, revealing suitability from 100 to 75% over northern Portugal, while central and southern Portugal show values in the approximate range of 25–50%. For future climates, a progressive and significant reduction in suitability was found, particularly for RCP8.5 and in the long-term period. Therefore, climatic changes embody an important threat to chestnut tree cultivation in Portugal, potentially affecting the plant physiology and phenology, ultimately leading to a reduction of the cultivation areas and yield. Adaptation strategies are critical to mitigate climate change detrimental impacts. It is indeed essential to implement measures that promote chestnut orchards’ adaptive capacity, reducing vulnerability and risks of exposure to increasingly warm and dry climates, but also warranting the sustainability of the sector.

Acknowledgments: The work is financed by the CoaClimateRisk project (COA/CAC/0030/2019) financed by the Portuguese Foundation for Science and Technology (FCT).
The low-power, user-configurable, digital broadband seismometer, analogue iteration: Güralp Certis
Authors: Mohr Sally , Reis Will , Barbara Rui , Cilia Marcella , Watkiss Neil , Hill Phil
Published: March 2022

Seismic monitoring systems are continuously reducing in size and power consumption to facilitate larger scale and more remote experiments.

Güralp have been leading the way to develop a portable, user-friendly broadband seismometer that is robust, omnidirectional in its operation and maintains excellent low-noise performance. The Certimus, released in 2020, incorporates this omnidirectional sensor technology with the Minimus digitizer to provide a proven broadband station. Now, the analogue sensor component has been packaged into a robust and compact stainless-steel housing that is suitable for post-hole and surface deployments, known as the Certis.  

Certis enables users to deploy in dynamic environments, without the need for cement bases or precise levelling, as the sensor will automatically adjust to tilt up to +/- 90 degrees. Due to its small size, low weight and low power consumption, Certis significantly reduces the logistical requirements for broadband posthole deployments. In addition, the lack of levelling required allows for Certis to be easily deployed down hole without the need to manually adjust the sensor’s orientation.

Certis has a wide frequency range of 120s to 100Hz with a remote, user-selectable long period corner. The Certis design is compatible with any commercially available broadband digitizer, however increased functionality is available with the Minimus digitizer, including access to advanced state-of-health parameters.

Güralp has developed a range of accompanying accessories that expand on the functionality of Certis and Certimus. The Portable Power Module offers a compact power solution that can power offline stations for up to 6 weeks. Due to portability of both Certis and Certimus, custom-designed backpacks and smart cases allow for users to easily transport multiple systems into the field. After installation of a buried Certimus, users can easily access data from the microSD card without disturbing the sensor using a Surface Storage Module in line with the GNSS receiver.
3D Monte-Carlo Simulations of Ganymede's Water Atmosphere - Predictions for JUICE/PEP/NIM
Authors: Vorburger Audrey , Shahab Fatemi , Galli André , Liuzzo Lucas , Poppe Andrew , Wurz Peter
Published: March 2022

We present 3D Monte-Carlo simulation results for the surface-sputtered and sublimated H2O molecules in Ganymede's atmosphere. To calculate particle fluxes onto Ganymede's surface, we use test particle model results for electrons, thermal H+ and O+, energetic H+, O++, and S+++, with unprecedented energy resolution. In addition, besides a thermal model based on Galileo measurements, we use recently published surface water content maps and recently measured water sputter yields.

Our simulations show that for the sputtered atmosphere, it is mainly the impinging O+, O++, and S++ ions that deliver H2O to the atmosphere, while electrons and protons only play a minor role in comparison. With Ganymede's surface temperature ranging from 80 K to 150 K (the latter being an upper bound), most returning H2O molecules stick to the surface. As a consequence of this, the morphology of Ganymede's magnetosphere, and the resulting patterns in the precipitation maps, are well preserved in the exosphere up to altitudes of a few thousand kilometers.

In the sub-solar region, it is the sublimated H2O that dominates the atmosphere by up to four orders of magnitude. The sublimated atmosphere quickly decreases with altitude, though, and sputtering becomes the dominant release process for H2O molecules reaching beyond a few hundred kilometers altitude. The sublimated H2O atmosphere is thus quite substantial but highly limited in spatial extent.

In addition to our most important modeling results concerning Ganymede's H2O atmosphere, we will also discuss their implications for spacecraft observability. Using the recently updated JUICE trajectories (CREMA 5), we will show which atmospheric populations (sublimated and/or sputtered H2O) will be encountered during the different Ganymede orbit phases (elliptical, high polar, and low polar). Finally, we will present expected measurement results for the Neutral and Ion Mass spectrometer (NIM), part of the Particle and Environment Package (PEP) onboard JUICE / ESA.
Occurrence and fate of pharmaceuticals in urban groundwater
Authors: Jurado Anna , Labad Francesc , Scheiber Laura , Criollo Rotman , Pérez Sandra , Ginebreda Antoni
Published: March 2022

Sustaining healthy living conditions in urban areas is a tremendous challenge in the European Union, and central to this mission is the supplying of freshwater resources. However, rapid urban growth and climate change will negatively impact water resources. Therefore, water shortage is encouraging research into potential alternative freshwater resources such as urban groundwater. Sometimes, urban groundwater is pumped to prevent damage to underground structures. This is the case of the underground parking lot of Sant Adrià del Besòs (Barcelona, NE Spain), where large amounts of urban groundwater are pumped to avoid seepage problems, which are directly poured to the sewage system.  This consideration ponders if this urban groundwater might be used as safe drinking-water because urban aquifers contain a vast array of pollutants such as pharmaceuticals.

This work investigated the occurrence and fate of more than 100 pharmaceuticals in the shallow aquifer of the Besòs Delta River, which main contamination source is a polluted river that receives discharges from wastewater treatment plants. To this end, river and groundwater samples were collected from February to May 2021 for the analysis of pharmaceuticals using a solid-phase extraction and high pressure liquid chromatography coupled to high resolution mass spectrometric methodology (HPLC-HRMS). Preliminary results showed that, in more than 70% of the samples, several pharmaceuticals such as anticonvulsants, antihypertensives, antibiotics, and antivirals were detected. More precisely, 38 substances were detected in all river samples and 15 were ubiquitous in groundwater samples.  The range of concentrations for all the compounds was between 2 ng/L and up to 880 ng/L. Moreover, the behavior of the compounds along the bank filtration until reach the pumping site, close to the parking lot, suggested that the natural attenuation of the pharmaceuticals likely to adsorption or oxidation-reduction processes occurred, as groundwater sampling points located close to the river presented the highest concentrations for the detected substances.  This observation allows inferring that the pumped urban groundwater could be used for different purposes including drinking water but further studies are required to quantify the coupled processes that control their fate in urban aquifers.
Validation of conventional and retracked Sentinel-3 observations along the Norwegian coast
Authors: Tomic Matea , Joodaki Gholamreza , Breili Kristian , Gerlach Christian , Ophaug Vegard
Published: March 2022

Satellite altimetry is one of the fundamental techniques for Earth observation, which provides precise measurements with frequent sampling and global coverage. However, its performance is degraded in coastal areas due to different factors, such as land contamination, erroneous tropospheric corrections or complex tidal patterns. In order to improve performance of satellite altimetry in the coastal zones, an increasing number of dedicated coastal altimetry products have been developed and validated in specific areas in later years. Those products are based on the improved analysis of backscattered signals in order to increase accuracy of altimetry observations in the coastal zones. One such product is the Adaptive Leading Edge Subwaveform (ALES) retracker, specifically aimed at the issue of land contamination. As of yet, it has not been validated along the whole, complex Norwegian coastline, with thousands of small islands, narrow fjords, and rough topography.  Thus, this study aims to validate the ALES retracker along the Norwegian coast, comparing conventional and ALES-retracked Sentinel-3 A/B observations with tide gauge observations. Altimetry-tide gauge comparison pairs are found by considering altimetry observations within optimum radii around each tide gauge, determined by minimizing the root mean square of differences (RMSD) for a range of candidate radii. It was found that the optimum radii for tide gauges located towards the open ocean are smaller than for those located inside fjords, because the observation accuracy degrades in the latter areas. Thus, it was necessary to increase radii, i.e. to include more points on the open-sea, for tide gauges inside fjords in order to minimize the RMSD. It was concluded that the ALES dataset generally gave better results (in terms of RMSD and correlation to the tide gauges) than conventional datasets, as well as giving a larger number of valid observations. The results are promising for future optimal combination of altimetry observations with other available sea-level observations in the coastal zone, e.g., from tide gauges, ships, unmanned surface vehicles (USVs) or airborne LiDAR. A prerequisite for such a combination is a reliable error description of each data type, to which the current study serves as a contribution. 
Snow surface water isotope variability driven by vapor-snow exchange
Authors: Wahl Sonja , Steen-Larsen Hans Christian , Hughes Abigail G. , Zuhr Alexandra , Faber Anne-Katrine , Jones Tyler R. , Dietrich Laura J. , Behrens Melanie , Reuder Joachim , Hörhold Maria
Published: March 2022

Observed variability in summer surface snow isotopic composition (δ18O, δD) cannot solely be explained by precipitation events. This variability however, influences the overall summer isotope signal that is archived in ice cores. It is therefore important to explain the origin of such post-depositional modifications of the snow isotope signal to ensure an optimal interpretation of ice core isotope records. The continuous exchange of humidity between the atmospheric vapor reservoir and the snow surface through sublimation and deposition could be a key process. Yet, in the past, the surface humidity flux has been disregarded as influential for the formation of the isotope signal in snow based on the assumption of the absence of isotopic fractionation during sublimation. Here we show evidence of isotopic fractionation during snow sublimation through a combination of laboratory experiments, in-situ observations from the Greenland Ice Sheet, and snow surface modeling. We document substantial isotopic enrichment in the uppermost centimeters of snow induced by sublimation and find that the in-situ observed summer season temporal evolution of the snow surface isotopic composition (in between precipitation events) can be attributed to surface humidity fluxes. We further discuss the nature and the underlying physical process of fractionation during sublimation. Our results lead to an improved process understanding and necessitate the implementation of fractionation during the sublimation process in isotope-enabled climate models.
Future effects of glacier retreat on downstream runoff and hydropower generation in the Alps
Authors: Wallner Mario , Abermann Jakob , Bachner Gabriel , Frei Elisabeth , Schöner Wolfgang , Steininger Karl
Published: March 2022

Due to climate change, glaciers are retreating worldwide. Among different consequences, the decline of meltwater in rivers will lead to a reduction in runoff. The aim of this work is to quantify the changes in runoff and the impact on selected hydropower plants in different drainage basins in the Alps until 2100.

Outputs from the Global Glacier Evolution Model (GloGEM), which uses 14 General Circulation Models to compute the future evolution of the glaciers worldwide, were used to determine past and future runoff from glaciers individual hydropower plants’ catchments. Measured runoff data at selected locations along rivers was used to compute the share of glacier runoff in total discharge. The computed river runoff was subsequently applied to determine the reduced electricity production of the hydropower plants.

The results reveal a decrease in summer runoff at all investigated power plants by 2100. However, large differences occur among the different catchments. In particular, geographical characteristics, such as glacier size and altitude, determine the intensity and timing of the decline. Areas located further away from glaciers, particularly in the North of the Eastern Alps, show the strongest reduction in glacier runoff (up to 86% compared to 1986-2015). In contrast, mountainous catchments and the South of the Alps are mostly affected by a decrease in river discharge (up to 33% compared to 1986-2015). Due to the dry summer climate, the summer runoff in these areas is reliant on the glacier discharge. This is also evident in the impact on hydropower production. For the run-of-river plants along the Rhone, one has to expect a decrease in summer production of up to 20%, which corresponds to an annual loss of € 5.3 Million. The losses are even higher for storage power plants located in catchments with a big glacier cover. For these, annual losses of up to € 35.0 Million were determined for the period 2071-2100.
Distributing your GPU array computation in Python
Authors: Tomlinson Jacob
Published: March 2022

There are many powerful libraries in the Python ecosystem for accelerating the computation of large arrays with GPUs. We have CuPy for GPU array computation, Dask for distributed computation, cuML for machine learning, Pytorch for deep learning and more. We will dig into how these libraries can be used together to accelerate geoscience workflows and how we are working with projects like Xarray to integrate these libraries with domain-specific tooling. Sgkit is already providing this for the field of genetics and we are excited to be working with community groups like Pangeo to bring this kind of tooling to the geosciences.
Global intensification of flash droughts in the past and future
Authors: Yuan Xing , Wang Yumiao
Published: March 2022

Flash droughts have raised a wide concern in recent years. Besides many regional analyses, global distributions of flash droughts have been discussed in a few studies. With certain differences due to different drought indices or datasets, a few hotspots consistently show increasing flash droughts among studies. However, to date, there is no global picture on whether flash droughts have been intensified, or whether the intensification will continue into the future. Here we propose a method to quantify the intensification of global flash droughts, and investigate the historical trends (trends in the past 60 years) by using global reanalysis data and CMIP6 climate models with or without human-induced climate change. The human fingerprint can be identified for the global trends, which suggests the important role of anthropogenic intensification of global flash droughts in the past. Moreover, future projection of flash drought is also carried out over IPCC SREX regions by using CMIP6 future scenarios. The results show that intensification of flash droughts is projected to continue across most regions, with larger increase under higher emission scenarios. This raises an urgent need to adapt to the intensifying flash droughts in the future.
Faulting induced by underground magma migration: new insights from detailed field analysis (Campi Flegrei, Italy)
Authors: Diamanti Renato , Camanni Giovanni , Natale Jacopo , Vitale Stefano
Published: March 2022

Faulting triggered by magma migration at depth is a not-rare phenomenon in volcanic areas, where they can be found at very different scales. By analogue and numerical models, it has been shown that these types of faults can display a complex structure that often comprises an array of fault segments with both normal and reverse senses of movement. In this work, we analyzed in detail, and for the first time using field data, a fault array associated with the collapse induced by underground magma migration. The fault array crops out in cross-section within a recent volcanic succession in the Campi Flegrei caldera (southern Italy). Analyses focused on defining the spatial and temporal relationships between the normal and reverse fault segments of the fault array to provide insights into the process of collapse development. Based on geometric and displacement data, we propose that normal and reverse faults likely acted simultaneously to accommodate the collapse after a rapid phase of fault propagation.
Investigating the impact of topography on the stable boundary layer structure over complex terrain using Large eddy simulations
Authors: Muppa Shravan Kumar , Lapo Karl , Sungur Leyla , Babel Wolfgang , Thomas Christoph
Published: March 2022

Abstract: Large eddy simulations (LES) are performed to better understand the airflow, structure, and mixing processes in the stable boundary layer (SBL) in the bottom of a mid-range mountain valley, Fitchelgebirge, in Southern Germany. The simulated structure and evolution of the SBL over the complex terrain agreed well in comparison with the remote sensing measurements. The simulations were tested using different vertical grid spacings of 10 m, 5 m and 2 m and a stretched version starting at 1 m assuming flat terrain. The topography of the experimental site is complex with mountain ranges of around 700 m on the north and up to 1km on the south. There is a gap on the western side of the site where channel flows are possible. Additional simulations were conducted with topography from a digital elevation model containing elevational differences up to 400 m. Results showed an increased depth of the cold-air pool by up 30 m and lower near-surface temperatures with differences exceeding 5 K in the valley bottom when comparing topography against flat-terrain simulations. The structure of the cold-air drainage followed terrain contours indicating local slope flows being responsible for the enhanced cooling when topography was included, while flat-terrain runs showed no evidence of a coherent cold-air layer. Finer grid resolutions showed much improvement in the resolved cold-pool vertical and horizontal structure. LES output was also compared with in-situ and remote sensing observations in terms of hourly mean profiles of wind speed, direction, and potential temperature, and turbulence kinetic energy. The results highlight the importance of including the topography in SBL modeling for e.g. frost damage forecast, air-pollution studies, fog analyses, and computing greenhouse gas budgets since both the SBL turbulence and time-averaged flow are governed by the thermal structure which is forced by topography even in relatively gentle mountainous terrain in mid-latitude regions.
The effects of tides on vertical motion in the Mediterranean Sea
Authors: McDonagh Bethany , Clementi Emanuela , Pinardi Nadia , Goglio Anna Chiara , Cessi Paola
Published: March 2022

Tidal forcing in numerical models is necessary to correctly forecast the ocean, since tides are a significant source of energy and driver of mixing in the global ocean. In the Mediterranean Sea, the amplitude of tides is lower than in many other regions of the global ocean, with the exception of the Alboran Sea, North Adriatic, and Gulf of Gabes, but the effects of tides are not limited to parts of the basin with high tidal amplitude. Analysis of the relationship between tidal forcing and measures of vertical motion including mixed layer depth, vertical velocity, and vertical diffusivity have not previously been carried out throughout the Mediterranean Sea.

This work investigates the effects of tides on vertical motion in the Mediterranean Sea, using the hydrodynamic model corresponding to the Copernicus Monitoring Environment Marine Service (CMEMS) system, a baroclinic forecasting model for the Mediterranean Sea, integrated over 5 years. Several regions were selected for separate study, based on their tidal amplitude and the local importance of vertical dynamics, such as deep water formation. The inclusion of tides increased the mean mixed layer depth in winter in the Mediterranean Sea, as well as in most of the selected regions. The magnitude of vertical velocity was also increased by tides on a basin level, but did not increase consistently throughout the selected regions. Vertical diffusivity, Brunt-Väisälä frequency, and Richardson number results were also explored.

The relationship between tidal amplitude and vertical velocity was additionally studied from a theoretical perspective. This work developed a prognostic equation for vertical velocity which was then compared to model results.

Our improved understanding of the effects of tidal forcing on vertical motion in the Mediterranean Sea highlights the necessity of including tides in high resolution ocean models, and allows for the separation of their effects from the impact on vertical mixing due to other modelling choices such as the chosen parametrization of vertical diffusivity. 
BES-based biosensors for methane emissions assessment in freshwater ecosystems
Authors: Fernandez-Gatell Marta , Sanchez-Vila Xavier , Puigagut Jaume
Published: March 2022

Climate change is one of the most important and probable aspects influencing the stability of human societies. Anaerobic carbon oxidation by methane producing bacteria (MPB) in natural and human-made freshwater ecosystems influence the global greenhouse gas (GHG) emissions and its dynamics.  Moreover, these ecosystems are highly sensitive to climate change. However, GHG emissions assessment methodologies are complex and cannot be applied continuously. Thus, better tools to characterize methane emissions and its dynamics in these ecosystems are of capital importance to deal with climate change. Bioelectrochemical systems (BES) are devices that transform the chemical energy of organic and inorganic substrates into electric current thanks to the metabolic activity of the electroactive bacteria (EAB’s). EAB and MPB oxidate the same carbon source (acetate) and, therefore, current produced by EAB can be used as a proxy for methane formation. BES-based biosensors are an interesting type of biosensors since they do not need a transducer, can be manufactured using cost-effective materials and can be applied for real-time and remote location monitoring. The work presented aim to assess the potential use of the electric signal produced by a low-cost, membrane-less BES-based biosensor as an indicator of methane emissions. To this purpose, 3.8L PVC vessels representing a core of a shallow flooded ecosystem were constructed and a BES cell was placed in the centre for the biosensing assessment. Methane emissions were assessed through the close chamber method and analysed by gas chromatography coupled to a flame ionisation detector while the bio-electric signal was continuously recorded. Results show that the methane and the electric production follow a similar pattern, but are displaced in time, being the electric production faster than the methane one. Results indicate that the electric current of a BES-based biosensor has the potential to be used as an indirect measure of methane emissions.
Role of 3D propagation in shaping Solar Energetic Particle observables
Authors: Dalla Silvia
Published: March 2022

The propagation of Solar Energetic Particles (SEPs) has been described traditionally by means of a spatially 1D focussed transport approach. However in recent years a number of physical mechanisms that give rise to motion across the mean magnetic field have been studied. These include perpendicular transport associated with turbulence, guiding centre drifts and drift along the heliospheric current sheet. In this presentation such mechanisms will be reviewed and emphasis will be placed on how assumptions and scenarios based on a 1D approach need to be modified when looking at SEP propagation from a 3D perspective. Observables such as time intensity profiles and anisotropies obtained from 3D models will be discussed and compared with observations.
Land use change and meteorology effect on atmospheric ammonia as seen by IASI
Authors: Abeed Rimal , Viatte Camille , Clerbaux Cathy , Clarisse Lieven , Van Damme Martin , Coheur Pierre-François , Safieddine Sarah
Published: March 2022

Agriculture contributes to air pollution and is affected by atmospheric composition, meteorology and climate change. One of the important gases emitted from agricultural activities is ammonia (NH3), which makes up a large portion of the anthropogenic reactive nitrogen in the environment. Agricultural ammonia emissions contribute to the formation of inorganic fine particulate matter (PM2.5), causing multiple negative effects on human health and the overall air quality. Many studies proved the capability of the Infrared Atmospheric Sounding Interferometer (IASI) instrument aboard the Metop satellites in measuring ammonia from space. The series of 3 instruments provides a continuous view of the global atmosphere since 2006, allowing us to study NH3 and many other pollutants relevant to air quality.

In this presentation, we explore the interaction between atmospheric ammonia on the one hand, and land and meteorological conditions on the other hand. To start, IASI NH3 total columns and ERA5 land surface temperatures are used to estimate the NH3 emission potential from the soil in agricultural fields. In addition to temperature, the emission potential is affected by the soil physical properties, fertilizer application practices and the concentrations of NH3 near the surface. The results are used to validate the emission potential of NH3 as derived from chemistry transport model (CTM) simulations.

Then, we look at the spatio-temporal variability of ammonia, focusing on different source regions around the globe. The NH3 land-atmosphere exchanges depend on land cover and land use management, and on meteorology. We study this relationship in two test regions and periods: an agricultural region in Syria that was subject to land use change during the conflict, and over agricultural regions around safe megacities.

In Syria we show that the detected changes in NH3 concentrations is driven by land use/cover rather than meteorology.

Over megacities, in particular, Paris, Toronto and Mexico, the result is quite different. We show that the NH3 variability is mainly driven by meteorology, and interestingly, we can detect the fertilizers application period by looking at the NH3 – temperature relationship.
Towards operational climate prediction: ENSO-related variability as simulated in a set of state-of-the-art seasonal prediction systems
Authors: Suarez-Moreno Roberto , Svendsen Lea , Bethke Ingo , King Martin P. , Chiu Ping-Gin , Bilge Tarkan A.
Published: March 2022

In the last decade, high demands from stakeholders and policymakers have driven unprecedented research efforts directed to improve climate predictability. Nevertheless, attempts to get operational climate predictions on seasonal time scales have been far from skillful for a long time. Based on sources of predictability from the ocean, atmosphere and land processes, current state-of-the-art prediction systems are approaching operational predictability. This work examines and compares the ability of different prediction systems to simulate the variability of sea surface temperatures (SSTs) associated with El Niño-Southern Oscillation (ENSO) and the ENSO-forced response of hydroclimate variability in the North Atlantic-Europe (NAE) region. Seasonal hindcasts derived from two generations of the Norwegian Earth System Model (NorESM1-ME and NorESM2-MM) are used in addition to C3S data to generate time series of year-to-year variability that are validated against observational data. Our results reveal both the advantages and the limitations of these prediction systems to simulate ENSO-related variability, identifying model biases that prevent skillful predictability. Further efforts must be aimed at mitigating these biases in order to achieve fully operational predictions of paramount importance for the benefit of society.
Prediction of saltwater intrusion’ dynamics in coastal aquifer using modeling techniques: a case study in Northeastern Tunisia
Authors: Aouiti Soumaya , Hamzaoui–Azaza Fadoua , Zammouri Mounira
Published: March 2022

The groundwater, which present 30.1% of the global freshwater, is at risk of being contaminated by saltwater intrusion. The saltwater intrusion is the induced flow of seawater into freshwater aquifers. Saltwater intrusion can occur due to natural processes as well as over-abstraction of groundwater from coastal aquifers. Numerical modelling is a useful tool in helping hydrologists to understand and predict how saltwater intrusion occurs in coastal aquifers. These numerical models are based on the governing equations of groundwater flow and contaminant transport.

 In this paper, the extension of saltwater intrusion into the coastal aquifers, of the Bouficha region, has been investigated by modelling using SEAWAT in MODFLOW. The abstraction from the Bouficha groundwater had increased more than fourfold between 1993 and 2021. Numerical groundwater modelling is a powerful tool for evaluation, development and management of groundwater resources of this basin. A numerical groundwater model for Bouficha groundwater was developed using MODFLOW software (pm8) to simulate regional groundwater changes in the Bouficha groundwater under steady and transient state. The flow model was calibrated based on 29-years historical period.

For controlling the quality of Bouficha groundwater, and as the Bouficha groundwater is a costal aquifer, a transport model related to salinity was developed using SEAWAT package, in MODFLOW, based on historical salinity data of 28-years. The transport model was successfully calibrated in the steady and transient state.

The transport model was applied to examine how far the seawater transition zone will moved based on five future scenarios (pumping and climate change). The five flow scenarios were used to predict the salinity distribution in the Bouficha groundwater, using SEAWAT package, by extended the transport model until 2050.

The scenarios results indicate the total deterioration of the Bouficha groundwater’s quality. The predicted salinity shows that the Bouficha groundwater will be in critical status.

The sources of the Bouficha groundwater quality degradation are multiple: the seawater intrusion from the sea and from the Sebkha and a chloride input from agricultural activities (as transport boundary conditions).
Identifying Seismic Anisotropy Patterns and Improving Tomographic Images in the Alps and Apennines Subduction Environments with Splitting Intensity 
Authors: Confal Judith M. , Pondrelli Silvia , Baccheschi Paola , Faccenda Manuele , Salimbeni Simone , AlpArray Working Group the
Published: March 2022

Active and past subduction systems influence the interpretation and understanding of current tectonics and velocity structures of the upper mantle of the Alps and Apennines. Computational advances over the years made it possible to identify remnant and active slabs up to great depths. SKS splitting measurements revealed mostly clockwise rotation in the Alpine region and mostly splitting parameters parallel to the Apennines (with new measurements in Central Italy). More than 700 stations were used in this study to calculate splitting intensities and with those similar but more stable fast polarization directions were recovered compared to SKS measurements. Splitting intensity measurements support a possible mantle material flowing through a tear in the Central Apennines. In the Po Plain region as well as east of the Apennine mountains anisotropy seems to be weaker. Moreover the complexity of layered anisotropy, upper mantle flow through possible slab detachments, and subduction related anisotropy with a dipping axis of symmetry are difficult to recover. Due to directional dependency of splitting intensity measurements, they can be used in tomographic inversions to get depth dependent horizontal anisotropy. So far we are able to recover the most prominent splitting patterns and see some changes with depth, especially for anisotropic strength. In this study we intend to use our results to improve tomographic images of the upper mantle by mapping and comparing existing and new anisotropy measurements (e.g., SKS, Pn anisotropy, azimuthal anisotropy from surface waves tomography, and splitting intensities).
Modeling the variability of Martian O+ ion escape due to Solar Wind forcing
Authors: Modolo Ronan , Leblanc Francois , Chaufray Jean-Yves , Romanelli Norberto , Dubinin Eduard , Génot Vincent , Baskevitch Claire , Brain David , Curry Shannon , Lillis Robert
Published: March 2022

During the last decade, MAVEN space mission have emphasized a widespread spatial distribution of escaping O+ ions (Brain et al., 2015; Dong et al., 2015; Curry et al., 2015). Statistical studies have demonstrated that such structure is constant and present an asymmetry with respect to the solar wind convective electric field direction. In the Mars Solar Ecliptic coordinate system, continuous large O+ ion fluxes have been observed from the Martian wake to the Northward hemisphere. Global hybrid models have been developed since more than fiffteen years (Modolo et al., 2005, 2016; Brecht and Ledvina, 2006; Kallio et al., 2006) predicting and reproducing successfully the main characteristics of these escaping ion signatures. To further characterize this heavy-ion escape and its variability due to the solar wind forcing, global hybrid simulations have been performed with different set of upstream solar wind parameters. The impact of the solar wind drivers on the dynamics of O+ ion fluxes are reported and compared to the statistical ion fluxes maps derived from MAVEN/STATIC observations (Dong et al., 2015).

Brain, D. A., McFadden, J. P., Halekas, J. S., Connerney, J. E. P., Bougher, S. W., Curry, S., et al. (2015). The spatial distribution of planetary ion fluxes near Mars observed by MAVEN. Geophys. Res. Lett. 42, 9142–9148. doi:10.1002/2015GL065293

Dong, Y., Fang, X., Brain, D. A., McFadden, J. P., Halekas, J. S., Connerney, J. E., et al. (2015). Strong plume fluxes at Mars observed by MAVEN: An important planetary ion escape channel. Geophys. Res. Lett. 42, 8942–8950. doi:10.1002/2015GL065346

Curry, S. M., Luhmann, J. G., Ma, Y. J., Dong, C. F., Brain, D., Leblanc, F., et al. (2015). Response of Mars O+ pickup ions to the 8 March 2015 ICME: Inferences from MAVEN data-based models. Geophys. Res. Lett. 42, 9095–9102. doi:10.1002/2015GL065304

Modolo, R., Chanteur, G. M., Dubinin, E., and Matthews, A. P. (2005). Influence of the solar EUV flux on the Martian plasma environment. Annales Geophysicae 23, 433–444. doi:10.5194/angeo-23-433-2005

 

Brecht, S. H. and Ledvina, S. A. (2006). The Solar Wind Interaction With the Martian Ionosphere/Atmosphere 126, 15–38. doi:10.1007/s11214-006-9084-z

Kallio, E., Fedorov, A., Budnik, E., Sa¨les, T., Janhunen, P., Schmidt, W., et al. (2006). Ion escape at Mars: Comparison of a 3-D hybrid simulation with Mars Express IMA/ASPERA-3 measurements 182, 350–359. doi:10.1016/j.icarus.2005.09.018

 
The challenges of predicting drought-induced forest mortality using plant hydraulic models
Authors: Venturas Martin D. , Anderegg William R. L. , Trugman Anna T. , López Rosana , Gil Luis
Published: March 2022

Modeling forest drought-induced mortality is critical for predicting the impacts of climate change on ecosystems, natural resources, and global carbon- and water-cycles. The incorporation of mechanistic representations of how water moves through plants (i.e., plant hydraulics) in vegetation, land surface, and Earth system models has enabled estimating the degree of vascular damage that plants experience due to drought stress, with the possibility of mechanistically relating vascular stress to plant mortality. We used forest inventory data and a plant hydraulics model for predicting forest mortality across Western United States. We found that incorporating plant hydraulic model outputs of vascular damage and photosynthetic assimilation in generalized linear models and random forest models improved forest mortality predictions. Nevertheless, the variance explained by these models was relatively low. We use this study to highlight which are the challenges for predicting forest drought-induced mortality at landscape scales. We also propose future research lines that will help close existing knowledge gaps and improve mortality predictions.
Role of mean and variability change for changes in European seasonal extreme precipitation events
Authors: Wood Raul R.
Published: March 2022

The frequency of precipitation extremes is set to change in response to a warming climate. Thereby, the change in precipitation extreme event occurrence is influenced by both a shift in the mean and a change in variability. How large the individual contributions from either of them (mean or variability) to the change in precipitation extremes are, is largely unknown. This is however relevant for a better understanding of how and why climate extremes change. The mechanisms behind a change in either the mean or the variability can thereby be very different.

For this study, two sets of forcing experiments from the regional CRCM5 initial-condition large ensemble are used. A set of 50 members with historical and RCP8.5 forcing as well as a 35-member (700 year) ensemble of pre-industrial natural forcing. The concept of the probability risk ratio is used to partition the change in extreme event occurrence into contributions from a change in mean climate or a change in variability.

The results show that the contributions from a change in variability are in parts equally important to changes in the mean, and can even exceed them. The level of contributions shows high spatial variation which underlines the importance of regional processes for changes in extremes. Further, the results reveal a smaller influence of the level of warming and level of extremeness on the individual contributions then the seasonality or temporal aggregation (3h, 24h, 72h). These results highlight the need for a better understanding of changes in climate variability to better understand the mechanisms behind changes in climate extremes.