bluuebunny/crossref_metadata_2025 huggingface dataset:
Using CT scans to count varves in lake sediments. Application to Lake Sagtjernet, southeastern Norway
Authors: Ballo Eirik Gottschalk , Bajard Manon , Støren Eivind , Bakke Jostein
Published: March 2021

Annually laminated sediments, also called varves, are valuable natural archives to reconstruct past environments and climate. Until now, the most common and reliable procedure to count varves has been to produce overlapping thin sections of the entire sediment sequence and counting in the microscope — a process that can take months to complete. Replacing this laborious method has been a long ongoing process within the varve community, and a task that we now may be getting with advancements in analytical tools. This study assesses the use of CT scanning to produce varve chronologies, applying it to the ferruginous sediments of Lake Sagtjernet in southeastern Norway — the first non-glacial varved lake sediment sequence in Norway continuously covering the last 4300 years.

Microfacies analyses of the sediments show that the varves are formed by cyclical deposition of iron and manganese. Oxygen measurements through 2013-2014 show permanent anoxic bottom waters while the seasonal turnover only reaching a depth of c. 6 m (out of a total 12 m depth). Combined with measurements of iron from the water column (highly enriched in the bottom waters) we suggest to classify Lake Sagtjernet as a ferruginous meromictic lake.

Varve counting on CT scans resulted in a 4300-year chronology, which we compared to an independent radiocarbon chronology (based on 17 14C dates, radionuclide and 210Pb analyses). Our results show that all of the varve ages fall within the 95% confidence interval of the radiocarbon chronology. However, some sections of the sediments with lower concentrations of iron and manganese illustrate vague boundaries between laminae in the CT scans — increasing age uncertainties in the chronology. These age uncertainties can be reduced by using XRF scanning or thin sections in parallel with CT scans to evaluate the boundaries. Based on these results, we conclude that CT scanning is a fast and non-destructive method for producing varve chronologies.
Methane Stem Fluxes Under Elevated CO2
Authors: Barba Josep , Gauci Vincent
Published: March 2021

Tree stems can exchange CH4 with the atmosphere at rates that can strongly affect GHG budgets at regional scales. However, we do not know those fluxes’ sensitivity to different components of climate change, such as the increase in concentrations of atmospheric CO2. An increase in CO2 concentrations might result in a change of water use efficiency, reducing transpiration fluxes, which may enhance soil methanogenesis due to an associated increase in soil water content. Additionally, an increase of CO2 could also stimulate net primary production, increasing the supply of fresh carbohydrates to the rhizosphere, and thus stimulating CH4 production in soil anaerobic microsites which may themselves become larger or more numerous due to the additional oxygen demand placed by the fresh carbohydrate on the soil atmosphere. Given the positive relation between soil and stem CH4 exchange processes, any increase in soil CH4 production may result in higher stem emissions. However, that effect of soil production on stem fluxes might decrease with stem height, with lower fluxes or even CH4 uptake at higher stem heights. In this study, we present preliminary data on spatial and temporal variability of stem CH4 fluxes measured in mature oak trees growing under both control and elevated CO2 concentrations (~150 ppm above atmospheric concentrations) in a FACE experiment (free air CO2 enrichment; BIFoR-FACE). These data may be crucial for informing processed based models on how forests GHG fluxes might behave under predicted future climate conditions.
Petrologic constraints on subduction zone metamorphism from a coesite-bearing metapelite in the Northern Appalachian Orogen
Authors: Gonzalez Joseph P. , Baldwin Suzanne L. , Thomas Jay B. , Nachlas William O. , Fitzgerald Paul G. , Lanari Pierre
Published: March 2021

The Caledonian orogen formed following Paleozoic subduction of the Iapetus Ocean and preserves evidence of ultrahigh-pressure (UHP) metamorphism and exhumation of crustal rocks from mantle depths. The Appalachian orogen similarly formed in the Paleozoic following subduction of Iapetus Ocean crust, but evidence for (U)HP metamorphism in exhumed Appalachian rocks has been challenging to identify. We present results from a metapelite from high-pressure rocks of the Tillotson Peak Complex in the northern Appalachians, which formed during the middle-Ordovician Taconic orogeny. This sample contained mm-cm scale garnet porphyroblasts that host abundant mineral inclusions. Confocal Raman microspectroscopy of inclusions in the rims of a garnet porphyroblast identified relic coesite, preserved as a bi-mineralic inclusion composed of coesite in α-quartz. Raman depth profiling and 2-dimensional mapping indicate the relic coesite is ~10 μm3, suggesting that mineralogical evidence of UHP metamorphism in the Appalachians may be preserved only as μm-scale inclusions contained in polymetamorphosed rocks. We applied quantitative WDS X-ray maps acquired with electron microprobe, quartz-in-garnet elastic thermobarometry, and Zr-in-rutile trace element thermometry to further constrain the metamorphic history of the coesite-bearing metapelite. Garnet zoning patterns in conjunction with elastic and trace element thermobarometry applied to co-entrapped mineral inclusions suggest that garnet nucleated at 14-15.5 kbar and 420-520 °C, and continuously crystallized to 15-19.5 kbar and 470-560 °C during subduction zone metamorphism. Peak metamorphic conditions based on the stability field of coesite and on Zr-in-rutile thermometry from inclusions in the garnet rims suggest UHP metamorphism at >28 kbar and 530 °C. UHP metamorphism of pelitic sediments within the Taconic paleo-subduction zone invite comparisons with similar UHP rocks in the Caledonian orogeny. Future studies of UHP metamorphism in the Appalachian orogen will focus on constraining: 1) the spatial and temporal scales of UHP metamorphism, 2) the retrograde/exhumation P–T path of the coesite-bearing metapelite, and 3) the P–T history of other nearby metamorphic units, such as the Tillotson peak metabasites, to evaluate if these units shared a similar metamorphic history.
Modelling the vertical motions of the Alboran Sea since the Messinian salinity crisis: Topographic reconstruction and glacial-isostatic sea-level effects 
Authors: Heida Hanneke , Garcia-Castellanos Daniel , Jiménez-Munt Ivone , Estrada Ferran , Ercilla Gemma , Coulson Sophie , Mitrovica Jerry
Published: March 2021

The Messinian Salinity Crisis (MSC) was caused and terminated by changes in the Atlantic-Mediterranean connectivity in the western end of the Alboran Basin, a complex tectonic area affected by the Iberia-Africa collision and the presence of a subducted lithospheric slab beneath the Betic-Rif orogen.

The isostatic, tectonic and erosional effects on surface topography work on different spatial and temporal scales, and their relative contributions to the changes in connectivity and subsequent evaporite deposition and sea-level drop are difficult to constrain.

We perform 2D-planform flexural isostatic modeling using the Messinian Erosion Surface imaged in the Alboran Basin to reconstruct the topography and vertical motions of this region since the end of the MSC. The results constrain the original depth of the Messinian erosional features to test their consistency against the various models proposed for Mediterranean sea-level changes during the MSC.
We apply Glacial Isostatic Adjustment theory to quantify the time response of these vertical motions to the large MSC-related mass shifts (salinification, evaporite deposition and a kilometer-scale sea-level drop),  and their gravitational effects on sea-level in the Mediterranean. In particular, models for the Strait of Gibraltar allowus to identify the potential role of these effects as feedback mechanisms influencing the rates and duration of changes in the Atlantic-Mediterranean connectivity at the straits.  We will explore the possible implications of these for the timing of the closure of the last Atlantic-Mediterranean seaway.
Reactive nitrogen in the global upper troposphere from NASA DC8 and MOZAIC aircraft campaigns
Authors: Wei Nana , Marais Eloise A. , Wennberg Paul O. , Allen Hannah M. , Crounse John D. , Blake Donald R. , Neuman Andy J. , Huey Greg L. , Veres Patrick R. , Thompson Chelsea R. , Bourgeois llann , Peischi Jeff , Sauvage Bastien
Published: March 2021

Reactive nitrogen in the upper troposphere (~8-12 km) impacts global climate, air quality and the oxidizing capacity of the whole troposphere. Here we use aircraft observations from instruments onboard the NASA DC8 aircraft for campaigns from 1997 (SONEX) to the recent ATom campaign (2016-2018) and the MOZAIC commercial aircraft campaign (2003-2005) to address uncertainties in the dynamics of reactive nitrogen (NOy = NOx + NOx reservoir compounds) in the global upper troposphere (UT). Our initial analysis of the DC8 aircraft observations is consistent with previous work in that PAN is the dominant NOy component (average: 43%; range: 40-60%), followed by NOx (on average, 21%), with smaller contributions (on average, 3.5-12.5%) from pernitric acid (HNO4), organonitrate (RONO2) and nitric acid (HNO3). We go on to compare multiyear mean NOy from MOZAIC to the combination of all NASA DC8 campaigns to determine whether we can build a near-global climatology of NOy and its components to compare to GEOS-Chem to assess our understanding of these very important atmospheric components.
Simulation of the Cooking Organic Aerosol Concentration Variability in an Urban Area
Authors: Siouti Evangelia , Skyllakou Ksakousti , Kioutsioukis Ioannis , Ciarelli Giancarlo , Pandis Spyros N.
Published: March 2021

Cooking operations can be an important fine PM source for urban areas. Cooking emissions are a source of pollution that has been often ignored and are not included or are seriously underestimated in urban emission inventories. However, several field studies in cities all over Europe suggest that cooking organic aerosol (COA) can be an important component of the total organic PM. In this study we propose and evaluate a methodology for the simulation of the COA concentration and its variability in space and time in an urban area. The city of Patras, the third biggest in Greece is used for this first application for a typical late summer period. The spatial distribution of COA emissions is based on the exact location of restaurants and grills, while the emissions on the meat consumption in Greece. We estimated COA emissions of 150 kg d-1 that corresponds to 0.6 g d-1 per person. The temporal distribution of COA was based on the known cooking times and the results of the past field studies in the area. Half of the daily COA is emitted during dinner time (21:00-0:00 LT), while approximately 25% during lunch time (13:00-16:00 LT). The COA is simulated using the Volatility Basis Set with a volatility distribution measured in the laboratory and is treated as semivolatile and reactive. The maximum average COA concentration during the simulation period is predicted to be 1.3 μg m-3 in a mainly pedestrian area with a high density of restaurants. Peak hourly COA concentrations in this area exceed 10 μg m-3 during several nights. The local production of secondary COA is predicted to be slow and it represents just a few percent of the total COA.

 
Skillful seasonal prediction of North American summer hot days
Authors: Jia Liwei , Delworth Tom , Kapnick Sarah , Yang Xiaosong , Johnson Nathaniel , Cooke William , Lu Feiyu , Harrison Matthew , Rosati Anthony , Zeng Fanrong , McHugn Colleen , Bushuk Michell , Zhang Yongfei , Witternberg Andrew , Zhang Liping , Murakami Hiroyuki , Tseng Kai-chi
Published: March 2021

This study shows that the frequency of North American summer hot days are skillfully predictable months in advance in the newly-developed GFDL (Geophysical Fluid Dynamics Laboratory) SPEAR (Seamless System for Prediction and EArth System Research) seasonal forecast system. We also demonstrate that climate change, the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO) and atmosphere-land feedback all contribute to the seasonal predictive skill of the frequency of North American summer hot days. Using a statistical optimization method (Average Predictability Time) we identify two large-scale components of the frequency of North American summer hot days that are predictable with significant correlation skill. One component shows an increase in the frequency of summer hot days everywhere over North America and is highly predictable at least 9 months in advance. This component is related to a secular warming trend. Another predictable component shows largest loadings over the central U.S., and is significantly predictable 6 months ahead. This second component is related to the PDO and the AMO, and is significantly correlated with the central U.S. soil water. These findings have potential implications for predictions of North American summer hot days on seasonal time scales.
Sunspot Classifications & Solar Flare Prediction: Does machine learning improve upon Poisson-based prediction models?
Authors: McCloskey Aoife , Bloomfield Shaun , Gallagher Peter
Published: March 2021

Historically, McIntosh classifications of sunspots have been utilised for the prediction of solar flares, with modern day operational flare forecast services still reliant upon these classifications for their predictions. Here, building upon previous Poisson-based flare forecasting models that make use of Mcintosh classifications, a set of various machine learning (ML) techniques are applied to construct a set of new models to predict flares within a 24-hr period.

These ML algorithms are trained and tested using data from a range of independent solar cycle periods, cross-validation techniques are applied and the relative performance of each algorithm is compared. In order to make a direct comparison to Poisson-based forecasts, skill scores are calculated and the performance of each model is presented, results showing that the ML models perform well across multiple metrics. The implications these results have when compared with the previous Poisson-based approach are discussed as well as the problem of solar cycle dependence. Additionally, an exploration of the importance of the individual features (i.e., McIntosh components) on the performance of each prediction model and their physical implications are presented.
Investigating fire NOx emissions with TROPOMI
Authors: Richter Andreas , Lange Kezia , Latsch Miriam , Burrows John P.
Published: March 2021

Most of the anthropogenic emissions of nitrogen oxides (NOx = NO2 + NO) are linked to burning of fossil fuels for energy production, transportation or industrial processes. However, biomass burning and in particular large wild fires in tropical and sub-tropical regions can also be large sources of nitrogen oxides at least locally. Depending on the size of the fires, particles and gases can be lifted into the free troposphere and even higher, increasing the atmospheric lifetime of NOx and enabling long range transport.

The TROPOMI instrument on board of Sentinel 5 precursor (S5p) is a nadir viewing UV/vis imaging spectrometer launched in October 2017 and operationally providing data since July 2018. One of the main products that can be retrieved from TROPOMI spectra is tropospheric and total column NO2. Compared to previous UV/vis satellite instruments such as GOME, SCIAMACHY, GOME2 and OMI, TROPOMI has a higher spatial resolution of 3.5 x 5.5 km2. This reduced foot print size enables detection and evaluation of more localised sources such as individual fires and their plumes, and better separation of different contributions to the overall NO2 loading.

In this presentation, IUP-Bremen TROPOMI NO2 retrievals are evaluated for biomass burning signatures during the years 2018 to 2020, three years with very different burning seasons. The amounts and spatial distributions of NO2 from fires are compared between the years and between different fire regions, and their impact on regions downwind of the sources is investigated.
Applicability of crop models in the context of parametric insurance – a Caribbean case study
Authors: Monteleone Beatrice , Cesarini Luigi , Figueiredo Rui , Martina Mario
Published: March 2021

Evaluating the impacts of weather events on the agricultural sector is of high importance. Weather has a huge influence on crop performance and agricultural system management, particularly in those countries where agriculture is mainly rainfed. Climate change is expected to further affect farmers’ incomes since the risk of extreme weather events with a relevant impact on crop yields is predicted to increase.

Appropriate strategies to deal with the economic impacts of agriculture need to be developed, to enable farmers to quickly recover after a disaster. In this context, weather-based index insurance (also known as parametric insurance) plays a key role since it allows farmers to receive financial aid soon after a disaster occurs.

This study evaluates the applicability of crop models run with gridded data in the framework of index-based insurance to assess their added value in providing estimations of crop yield in case of drought events.

At first, the cropland area is identified using satellite data on Normalized Difference Vegetation Index (NDVI) and Leaf Area Index (LAI) retrieved from various sources, such as Sentinel and Landsat. Crop Type maps are then produced to identify the location of the different crops grown in a region. Then, weather data coming from stations are exploited to run the AquaCrop crop model and estimate the crop yield for the areas near the weather stations.

Since in many countries weather stations are often missing or do not record continuously, the AquaCrop model is also run with gridded data coming from reanalysis, specifically ERA, which is a product released by the European Centre for Medium Range Weather Forecast and has the advantage to provide daily estimation of  multiple weather parameters on a 0.25° grid. In addition, ERA5 has a short latency time (in the order of days) and thus allows a near-real time monitoring of the crop growing season. The AquaCrop outputs obtained when the model is run with the station data are then compared to the ones obtained when the model is run with gridded data. The performance of the two model configurations (weather parameters coming from stations or from ERA5) in estimating yield reductions during drought events, previously identified using the Probabilistic Precipitation Vegetation Index (PPVI), are evaluated.

The framework was applied in the context of the Dominican Republic, a Caribbean country in which 52% of the national territory is devoted to agriculture. The Dominican agricultural industry has as main products cocoa, tobacco, sugarcane, coffee, cotton, rice, beans, potatoes, corn and bananas. Results shows that gridded data can be a valuable tool to provide near-real time estimates of the crop growing season and thus help in forecasting final crop yields in near-real time.
The ikaite to calcite transformation: A key to understanding the palaeoclimatic significance of glendonites?
Authors: Vickers Martin , Vickers Madeleine , Rickaby Rosalind , Wu Han , Bernasconi Stefano , Ullmann Clemens , Bohrmann Gerhard , Spielhagen Robert , Thibault Nicolas , Korte Christoph
Published: March 2021

Keywords: Ikaite; Glendonite; Palaeoclimate; Powder X-Ray Diffraction; Clumped isotope thermometry

Marine sedimentary ikaite is the parent mineral to glendonites, stellate pseudomorphs found throughout the geological record. Glendonites are a controversy in palaeoclimatic studies as there is an ongoing debate as to whether their presence in sedimentary successions may be used as cold-climate indicators. Glendonites are typically found associated with glacial sediments, and for a long time ikaite was believed to only nucleate and grow at temperatures < 7 °C. However, with the successful laboratory synthesis of ikaite at higher temperatures, the climatic significance of glendonites was brought into question. This study uses a combination of physical and inorganic chemistry techniques to demonstrate the variable stability of natural marine sedimentary ikaites over short (minutes to hours) and longer (weeks to months) timescales, both between ikaite samples, and in a given ikaite. We examine the nucleation of calcite from the destabilized ikaite, observing that this process is much more complex than previous studies suggest. We demonstrate that over much longer (e.g. months or more) timescales, natural marine sedimentary ikaites are not stable above 5 °C, and thus glendonite presence in sedimentary successions may be considered cold climate indicators.
GioGas: Edutainment and Gas Hazards
Authors: Cirillo Francesca , Avvisati Gala , Carapezza Maria Luisa , D'Addezio Giuliana , Marotta Enrica , Peluso Rosario , Scelzo Antonio , Sciarra Alessandra , Tarchini Luca
Published: March 2021

The Istituto Nazionale di Geofisica e Vulcanologia (INGV) has developed an interactive application, for educational purposes, in order to make schools aware of the dangers deriving from radon, and in general from harmful gases (gas hazards), near volcanic areas.

To raise children awareness on the dangers related to an invisible enemy, often odorless “gases”, is not a simple task. Since our target are children between 11 and 13 years of age, we decided to develop a videogame with the scope of enabling them to learn the most appropriate solutions for identifying/avoiding/managing hazards. The use of a videogame for spreading information on gas hazards makes learning fun and, at the same time, feasible in a historic moment where Covid-19 does not allow for lessons to be physically partaken in a classroom. Furthermore, this type of learning known as “edutainment” is more effective, captivating and meaningful, allowing students to acquire a more concrete and longer remembered knowledge.

The videogame, called GioGas, is a single player game running on both Android mobile phone and personal computers. GioGas has been developed using the Role Playing Game Maker MV graphic engine. The engine provides a map editor and several characters allowing for the creation of various biomes, also including the possibility to insert music. From the technical point of view the engine is based on javascript for the events creation and triggers management simplifying porting on mobile and desktop operating systems.

The game characters are a INGV researcher, staying in a rented house during his vacation, and an elderly lady that asks for help to understand if her grandchild’s health issues are related to the recent digging of a well nearby the house. The characters move around in the virtual environment in different locations organized in several levels. Through the game, the student will learn the symptoms caused by gases, the instruments and the techniques to identify/measure them and the solutions to adopt to solve the problem. During the game, the researcher will hand out information and the student will choose which solution to apply: this will also stimulate student inclination to problem solving and overview capacities. Each solution will return a result in terms of risk mitigation and a score, from 1 to 3, based on the effectiveness of the identified solution.

In the future, to add more stimulating and engaging elements for the student, a multiplayer mode will be developed, giving the students the possibility to challenge themselves.
Rare Earth Elements distribution in grapevine varieties grown on different types of soils: examples from Mount Etna and from the Hyblean Plateau (Sicily, Italy)
Authors: Punturo Rosalda , Vaccaro Carmela , D'Antone Carmelisa
Published: March 2021

The present contribution reports the results from a geochemical and statistical study aimed to identify in the Rare Earth Elements (REEs) absorption a good fingerprinting marks for determining the territoriality and the provenance of Vitis vinifera L. into two different geological contexts in Sicily: the volcanic district of Mount Etna and the carbonate platform of the Hyblean Plateau (Sicily, southern Italy). Our aim was to: i) define if the REEs  distribution in plants may reflect the composition of the provenance soil under similar climate conditions; ii) highlight differences, if any, in REE absorption within the various parts of the plants; and  iii) propose, for selected cultivar of Vitis vinifera L., a REE fingerprint in the Etna Volcano and Hyblean carbonate soils as well as to recognize characteristic REEs pattern.

To this aim, REE content has been determined by ICP-MS investigation in the soils and in the selected grapevine varieties for all the following parts: leaves, seeds, juice, skin and berries. Geochemical data have also been approached by a multivariate statistical analysis of the Principal Component Analysis (PCA), together with the Linear Discriminant Analysis (LDA).

The work permitted to highlight various REE distribution within the various parts of the plant and assessed as each grape variety presents a characteristic geochemical pattern in the absorption of REEs in relationship with the geochemical features of the type of soil on which the grapes grew.
Comparative analysis of throughfall event response for 6 different forest stands
Authors: Blume Theresa , Schneider Lisa , Dreibrodt Janek , Güntner Andreas
Published: March 2021

Rainfall redistribution by forest canopies differs between tree species and can play an important role for tree water availability and groundwater recharge. A thorough understanding of these relationships will improve our ability to predict future impacts of climate and forest structural changes on the water balance of forest stands.

In the TERENO observatory in the Müritz National Park (north-eastern Germany), throughfall was continuously measured at 7 sites with different dominant tree species and ages: young and old beech, young and old pine, and the mixed stands oak/beech, pine/beech, and pine/oak/beech. To this end, 5 trough-based throughfall monitoring systems with a total collecting area of 6.6 m² per site were installed at each site. Furthermore, stemflow was measured with tipping buckets at 5-10 trees per site. This added up to a total at 40 trees (18 pines, 15 beeches, 7 oaks) providing a unique high-temporal resolution data set of stemflow response. This dataset covers almost 5 years, offering a good data base for detailed event analyses.

During the measurement period we identified 534 rainfall events. However, to maintain good comparability, we removed all events where more than one of the five trough systems per site failed, which left us with 346 rainfall events for throughfall and 184 rainfall events for stemflow. Due to the large number of events we were able to compare winter and summer events as well as the influence of different precipitation characteristics. Statistical models were used to investigate forest-stand specific relationships between throughfall and meteorological conditions. The comparison of these relationships between the forest stands offered additional insights into forest structural controls of throughfall. 
Calcification depth of deep-dwelling planktonic foraminifera from eastern North Atlantic: evidence from stable oxygen isotope ratios of shells from plankton tows 
Authors: Rebotim Andreia , Voelker Antje H. L. , Jonkers Lukas , Waniek Joanna J. , Schulz Michael , Kucera Michal
Published: March 2021

Stable oxygen isotopes (δ18O) of planktonic foraminifera are one of the most used tools to reconstruct environmental conditions of the water column. Since different species live and calcify at different depths in the water column, the δ18O of sedimentary foraminifera reflects to a large degree the vertical habitat and interspecies δ18O differences and can thus potentially provide information on the vertical structure of the water column. To fully unlock the potential of foraminifera as recorders of past surface water properties, it is necessary to understand how and under what conditions the environmental signal is incorporated into the calcite shells of individual species. Deep-dwelling species play a particularly important role in this context, since their calcification depth reaches below the surface mixed layer. Here we report δ18O measurements made on four deep-dwelling Globorotalia species collected with stratified plankton tows in the Eastern North Atlantic. Size and crust effects on the δ18O signal were evaluated showing that a larger size increases the δ18O of Globorotalia inflata and Globorotalia hirsuta, and a crust effect is reflected in a higher δ18O in Globorotalia truncatulinoides. The great majority of the δ18O values can be explained without invoking disequilibrium calcification. When interpreted in this way the data imply depth-integrated calcification with progressive addition of calcite with depth to about 300 m for G. inflata and to about 500 m for G. hirsuta. In Globorotalia scitula, despite a strong subsurface maximum in abundance, the vertical δ18O profile is flat and appears dominated by a surface layer signal. In G. truncatulinoides, the δ18O profile follows equilibrium for each depth, implying a constant habitat during growth at each depth layer. The δ18O values are more consistent with the predictions of the Shackleton (1974) paleotemperature equation, except in G. scitula, which shows values more consistent with the Kim and O’Neil (1997) prediction.  In all cases, we observe a difference between the level where most of the specimens were present and the depth where most of their shell appears to calcify.
From rice-microalgae As removal to electricity generation using a microbial fuel cell: a new conceptual approach for the agro-industrial sector
Authors: Ottoni Cristiane , Vidigal Patrícia , Abreu Maria Manuela , Esquível Glória , Sousa Isabel , Brito António
Published: March 2021

The presence of As in soil and water can be considered a global threat that can potentially contaminate the food chain. Thus, the remediation of these resources and the decrease of As concentration is a major research goal, especially in rice that tends to accumulate As in the grain. Arsenic uptake by plant species depends on As concentration in the available fraction of the soil and speciation. Several agronomic strategies have been tested to decrease As concentration in rice grain. These include water management, nutrient management and biological approaches among others. In this context, microalgae is known to be effective in the uptake and metabolize of potentially toxic elements like As, which is a cost-effective approach compared to other agronomic strategies. However, in the view of the the current global panorama of growing respect for environmental preservation and focus on energy generation from renewable resources (including domestic and industrial waste products), the use of Microbial Fuel Cells (MFC) has been gaining increased attention. The MFCs have enormous potential as they simultaneously promote the treatment of different types of waste and generate electricity. This is possible due to the conversion of the chemical energy available in the biodegradable substrates directly into electricity, through the catalytic action of electrogenic bacteria attached to the anodic electrode. We aim to develop and establish a protocol for biodegradation of As, captured by microalgae grown in paddy rice fields, in compounds less harmful to the environment and at the same time generating electricity in a continuous process. For this purpose, a selection will be made of cathodic-algae, different electrodes and membrane materials, as well as the operating conditions of MFC. The results monitored are chemical oxygen demand, nitrogen, phosphorus, pH, and production of electricity. At the end, we will be able to evaluate the possibility of decreasing rice As uptake by microalgae that will serve as a raw material for the production of electricity. This will contribute both to help achieve the new European Green Deal policy framework linked with the UN 17 Sustainable Development Goals for 2030, by promoting a resource-efficient and competitive agri-economy while guarantying the health and well-being of citizens from environment-related risks and impacts, covering the “farm to fork” food value chain.
Assessing recently improved precession-nutation models 
Authors: Ferrándiz José M. , Juárez Miguel A. , Belda Santiago , Baenas Tomás , Modiri Sadegh , Heinkelmann Robert , Escapa Alberto , Schuh Harald
Published: March 2021

In 2020 new estimations of nutation amplitudes or precession parameters have been published or presented at main meetings. The derivation of corrections to improve the current precession-nutation models was encouraged by Resolution 5 of the 2019 General Assembly of the International Association of Geodesy (IAG). Besides, the GGOS/IERS Unified Analysis Workshop held in October 2019 recommended that effort to be prioritized among the tasks of the current IAU/IAG Joint Working Group on Improving Theories and Models of the Earth’s rotation (JWG ITMER).

This presentation is intended to present comparisons of some of those new semi-empirical and semi-theorical precession-nutation models developed by different authors from either VLBI solutions of individual analysis centers or combinations of them. The models recently introduced by the authors that were reported at the AGU 2020 Fall Meeting are included in this assessment.
Experiments on wind-driven heat exchange processes over melting snow
Authors: Haugeneder Michael , Jonas Tobias , Reynolds Dylan , Lehning Michael , Mott Rebecca
Published: March 2021

Snowmelt runoff predictions in alpine catchments are challenging because of the high spatial variability of the snow cover driven by various snow accumulation and ablation processes. In spring, the coexistence of bare and snow-covered ground engages a number of processes such as the enhanced lateral advection of heat over partial snow cover, the development of internal boundary layers, and atmospheric decoupling effects due to increasing stability at the snow cover. The interdependency of atmospheric conditions, topographic settings and snow coverage remains a challenge to accurately account for these processes in snow melt models.
In this experimental study, we used an Infrared Camera (VarioCam) pointing at thin synthetic projection screens with negligible heat capacity. Using the surface temperature of the screen as a proxy for the air temperature, we obtained a two-dimensional instantaneous measurement. Screens were installed across the transition between snow-free and snow-covered areas. With IR-measurements taken at 10Hz, we capture the dynamics of turbulent temperature fluctuations over the patchy snow cover at high spatial and temporal resolution. From this data we were able to obtain high-frequency, two-dimensional windfield estimations adjacent to the surface.

Preliminary results show the formation of a stable internal boundary layer (SIBL), which was temporally highly variable. Our data suggest that the SIBL height is very shallow and strongly sensitive to the mean near-surface wind speed. Only strong gusts were capable of penetrating through this SIBL leading to an enhanced energy input to the snow surface.

With these type of results from our experiments and further measurements this spring we aim to better understand small scale energy transfer processes over patch snow cover and it’s dependency on the atmospheric conditions, enabling to improve parameterizations of these processes in coarser-resolution snow melt models.
Organic pollutants from Indonesian peatland fires: regional influences and its impact on lower the stratospheric composition
Authors: Rosanka Simon , Franco Bruno , Clarisse Lieven , Coheur Pierre-François , Wahner Andreas , Taraborrelli Domenico
Published: March 2021

In 2015, the particularly strong dry season in Indonesia, caused by an exceptional strong El Niño, led to severe peatland fires. Due to the high carbon content of peatland, these fires are characterised by high volatile organic compound (VOC) biomass burning emissions. The resulting primary and secondary pollutants are efficiently transported to the upper troposphere/lower stratosphere (UTLS) by the developing Asian monsoon anticyclone (ASMA) and the general upward transport in the intertropical convergence zone (ITCZ). In this study, we assess the importance of these VOC emissions for the composition of the lower troposphere and the UTLS by performing multiple chemistry simulations using the global atmospheric model ECHAM/MESSy (EMAC). In a first step, we find that EMAC properly captures the exceptional strength of the Indonesian fires based on the comparison of modelled columns of the biomass burning marker hydrogen cyanide (HCN) to spaceborne measurements from the Infrared Atmospheric Sounding Interferometer (IASI). In the lower troposphere, the increase in VOC levels is higher in Indonesia compared to other biomass burning regions. This directly impacts the oxidation capacity and leads to a high reduction in hydroxyl radicals (OH) and nitrogen oxides (NOx). In general, an increase in ozone (O3) is predicted close to the peatland fires. However, particular high concentrations of phenols lead to an O3 depletion in eastern Indonesia. By employing the detailed in-cloud OVOC oxidation scheme Jülich Aqueous-phase Mechanism of Organic Chemistry (JAMOC), we find that the predicted changes are dampened and that by ignoring these processes, global models tend to overestimate the impact of such extreme pollution events. The upward transport in the ASMA and the ITCZ leads to elevated VOC concentrations in the UTLS region. This also results in a depletion of lower stratospheric O3. We find that this is caused by a high destruction of O3 by phenoxy radicals and by the increased formation of NOx reservoir species, which dampen the chemical production of O3.
Climatology of very high ionospheric electron temperature occurrences as observed by Swarm constellation
Authors: Coco Igino , Consolini Giuseppe , De Michelis Paola , Giannattasio Fabio , Pezzopane Michael , Pignalberi Alessio , Tozzi Roberta
Published: March 2021

After more than seven years in orbit, the ESA Swarm satellites have provided an already large statistics of measurements of several important physical parameters of the ionosphere. In particular, electron density and temperature are measured by pairs of Langmuir Probes, and the quality of such data is now considered good enough for many studies, either science cases or climatological characterisations. Concerning specifically the electron temperature, a rather elusive parameter which is quite difficult to correctly characterize “in situ”, and for which the past literature is not so abundant with respect to other ionospheric physical quantities, the overall distributions observed by Swarm are qualitatively consistent with expectations from theory and past observations. However, a non-negligible amount of high and very high electron temperature values is regularly observed, whose distributions and properties are not trivial. In this study we aim at characterizing such features statistically as a function of latitude, local time, and season.
Flood impacts on Agriculture: The case study of Nonantola 2020 Flood event. 
Authors: Giusti Riccardo , Monteleone Beatrice , Borzì Iolanda , Martina Mario
Published: March 2021

Globally, about a third of all losses related to natural hazards are due to flooding. Many studies focused their attention on the estimation of flood damages to buildings and infrastructures. However, floods cause significant losses to the agricultural sector too and negatively affect rural economies due to their impacts on agricultural productivity.

Several tools to quantify flooding economic impacts on the agricultural sector have been proposed, such as the AGRIDE-c conceptual model, and the Joint Research Centre (JRC) depth-damage functions. However, the tools have rarely been validated against data collected from surveys.

The aim of this study is the comparison between the flood economic impacts on agriculture computes using both AGRIDE-c and the JRC tool and the ones retrieved from surveys.

A questionnaire for estimating flood economic impacts on agriculture was prepared and submitted to farmers shortly after the flooding event. The selected case study area was the town of Nonantola (near the city of Modena, Northern Italy), where a flooding event occurred on 6th December 2020. The flood was caused by the collapse of about 80m levee portion along the right bank of Panaro River resulting in an inundated area around 2000 hectares. The flood involved the Nonantola town where residential buildings and an active industrial area are located, although the dominant land use is agricultural land. The main local crops are represented by forage, wheat, vineyards, fruits (pears and plums) and sugar beet.

The questionnaire is divided into four main sections: The first section is related to the generic information on the farm, the second section to the data on the inundation and damage to crops, the third section to the information on past flood events and risk mitigation strategies eventually adopted during past and present events, the fourth section data to the insurance coverage.

Two existing crop damage models (AGRIDE-c and the JRC) were calibrated using three types of data: crop yields, crop selling prices and crop cost of production. Crop yields were obtained from the Italian National Statistical Institute (ISTAT), crop selling prices and costs of production were instead available from official sources such as ISMEA and Coldiretti (Italian association of farmers).

Finally, the proposed approach will allow the comparison between the damages experienced by farmers evaluated from questionnaires and the damages estimated by the two models in order to evaluate how the models simulate data directly collected from the field surveys.
How (not) to quantify hydrological changes using lacustrine carbonates? 
Authors: Kwiecien Ola , McCormack Jeremy
Published: March 2021

Lakes are sensitive to climate change and their sedimentary components play a pivotal role as environmental recorders. In the past, lacustrine carbonates have been utilized in a number of studies attempting at a quantitative reconstruction of rainfall and/or precipitation-evaporation changes based on the biogenic or bulk carbonate δ18O signature. While these studies are built on sound theoretical grounds of mass balance and kinetic isotopic fractionation, the challenge often overlooked is the mineralogically mixed nature of carbonates comprising the bulk.

We report a case study from Lake Van, the world’s largest alkaline lake. Our time series comprising ca. 140 ka documents not only changing proportions of surface water calcite and aragonite, but also diagenetic bottom-water dolomite and, for the first time in Lake Van, early diagenetic bottom-water aragonite. Importantly, in the Lake Van profile primary and early diagenetic carbonates (in particular aragonite) are concurrent rather than mutually exclusive. A comprehensive comparison of the δ18O and δ13C compositions of singled out water column, biogenic (ostracod valves) and diagenetic carbonates shows, that each of the fractions forms a distinctive cluster characteristic for the depth and timing of their formation. Also, the differences between δ18O values of concurrent deep-water carbonate phases exceed what is expected from mineral-specific fractionation. Our data suggest that, an uncritical and unchecked application of the isotopic composition of the bulk carbonate fraction in quantitative climate reconstructions can severely compromise the results. We also advocate that, among different carbonate fractions in Lake Van, monospecific biogenic samples most faithfully reflect the oxygen isotopic composition of the lake water contemporaneous to their deposition, while the carbon composition of biogenic samples is additionally influenced by the organism microhabitat.
Optimal design of an hydrogeophysical monitoring system of compacting volcanic aquifers (Tenerife Island)
Authors: Gonzalez Pablo J. , Charco Maria , Eff-Darwich Antonio , Lamur Anthony , Marrero Rayco , De Angelis Silvio
Published: March 2021

Groundwater in volcanic islands is usually the main source of freshwater, and it is essential for sustainable development. In Tenerife Island, groundwater extraction occurs by drilling horizontal water tunnels, called water galleries, as well as numerous coastal wells. Since around 1900, but especially since the 1960s, hundreds of water tunnels have been drilled for agriculture and freshwater supply. This has resulted in a sustained extraction of groundwater larger than the natural recharge, leading to a general water table decline, locally up to 200 m of down drop. Since 2000, satellite radar interferometry (InSAR) applied to measure surface deformation has located several subsidence bowls (e.g., Fernandez et al., 2009). The localized surface deformation patterns have been correlated with water table changes and hence aquifer compaction. However, no further investigations have been carried out to confirm which characteristics (chemical composition, texture, porous network, alterations, etc.) of the volcanic materials can control compaction process, and to which extent porous volcanic units, the most abundant material in Tenerife, can compact to explain the observed surface deformation. This lack of knowledge might affect the effectiveness of water management policies.

To investigate the compaction processes affecting the volcanic aquifer, we propose to set up a passive hydrogeophysical monitoring network composed of geodetic and seismological instruments. However, considering logistic constrains it is desirable to have as low as possible number of observation sites, whist maximizing the detection and characterization of the aquifer dynamics. Here, we explore different network configurations to maximize the spatial and temporal characterization of the compaction processes using machine learning methods (low-rank matrix techniques). We pose the network design as an optimization process with the aim to parsimoniously have as fewer as possible ground station sites, and have a low error on reconstructing spatiotemporal land subsidence observations. Land subsidence rates were estimated using Sentinel-1 radar interferometric observations from October 2014 to December 2020. This method allows for an optimal network configuration, with respect to the dual penalty function, which facilitate the decision making. Nevertheless, this type of network design should be regarded as proposals because some station site conditions are a priori unknown. Although, one could modify the penalty function to optimize the network considering additional types of information, e.g., geological materials, groundwater table time series, etc.

Fernandez, J., et al. (2009), Gravity-driven deformation of Tenerife measured by InSAR time series analysis, Geophys. Res. Lett., 36, L04306, doi:10.1029/2008GL036920.