bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochar vs magnesite amendments for metals immobilization: lab-scale and field experiments
Authors: Baragaño Diego , Arenas Lago Daniel , R. Gallego José Luis , Forján Castro Rubén
Published: March 2021

The process of industrial change has resulted in the creation of so-called ‘brownfields’ across Europe, particularly in urban areas, in the industrial sections of cities. The need to recover these brownfields can be linked to the new European Commission program "Zero Wastes", that is, to restore or recondition these areas by applying amendments made with by-products or green elements. In this sense, the capacities of magnesite and biochar, inorganic and organic soil amendments respectively, were tested to reduce metal availability and improve the properties of a soil severely contaminated by Cu, Cd, Pb and Zn. To this end, two implementation steps were performed.

First, 1 kg pots containing the polluted soil were amended with either magnesite or biochar and then determined metal availability and soil properties at days 15 and 75 in a greenhouse experiment. In addition, to evaluate the impact of the two treatments on plant growth, the experimental trials were carried out using Brassica juncea L. and compost addition. Both amendments, but particularly magnesite, markedly decreased metal availability. Soil properties were also improved, as revealed by increases in the cation exchangeable capacity. However, plant growth was inhibited by magnesite amendment. This effect was probably due to an increase in soil pH, cation exchange capacity and a high Mg concentration. In contrast, biochar increased biomass production whereas decreased the content of metals harvested. Then, a field scale experiment was performed in situ by means of treating 1 ton of the soil with the magnesite and also with the biochar. Brassica juncea L. was used for testing the impact on plants, and the experiment was monitored at 3, 30 and 60 days from the beginning of the experiment. Similar results to the greenhouse experiment were obtained.

In conclusion, the results indicate that magnesite amendment may be suitable for stabilizing contaminated soils (or even spoil heaps) where revegetation is not a priority. In contrast, although biochar has a lower, but still significant, capacity to immobilize metals, its use emerges as a promising tool for restoring soil properties and thus favoring plant growth.

Acknowledgment

This work was supported by the research projects NANOBIOWASH CTM2016-75894-P (AEI/FEDER, UE) and NANOCAREM MCI-20-PID2019-106939GB-I00 (AEI/FEDER, UE).

Diego Baragaño obtained a grant from the “Formación del Profesorado Universitario” program, financed by the “Ministerio de Educación, Cultura y Deporte de España”.

Arenas-Lago D. thanks to his postdoc contract ED481D 2019/007 (Xunta de Galicia and Universidade de Vigo).
Using a high-resolution regional climate model large ensemble to simulate the impact of extreme precipitation on flooding over small to medium-size catchments
Authors: Faghih Mina , Brissette François , Sabeti Parham , Tarek Mostafa
Published: March 2021

Recent studies show that the frequency and intensity of extreme precipitation will increase under a warmer climate. It is expected that extreme convective precipitation will scale at a larger than Clausius–Clapeyron rate and especially so for short-duration rainfall. This has implication on flooding risk, and especially so on small catchments (<500 km2) which have a quick response time and are therefore particularly vulnerable to short duration rainfall. The impact of the amplification of extreme precipitation as a function of catchment scale has not been widely studied because most of the climate change impact studies have been conducted at the daily time step or higher. This is because until recently the vast majority of climate model outputs have only been available at the daily time step.

This study has looked at the amplification of sub-daily, daily, and multiday extreme precipitation and flooding and its dependency on catchment scale. This work uses outputs from the Climex large-ensemble to study the amplification of extreme streamflow with return period from 2 to 300 years and durations from 1 to 24 hours over 133 North-American catchments. Using a large ensemble allows for the accurate empirical computation of extreme events with very large return periods.  Results indicate that future extreme streamflow relative increases are largest for smaller catchments, longer return period, and shorter rainfall durations. Small catchments are therefore more vulnerable to future extreme rainfall than their larger counterparts.
The roles of winds and waves in Arctic sea ice variability
Authors: Roach Lettie , Blanchard-Wrigglesworth Edward , Bitz Cecilia
Published: March 2021

It is broadly accepted that variability and trends in Arctic sea ice remain poorly simulated even in the most state-of-the-art coupled climate and climate prediction models. Here, we show that a modern coupled climate model (CESM1) is in fact able to reproduce the observed variability and decline in summer sea ice when winds are nudged towards values from reanalysis.  We argue that the nudged-winds framework provides a straightforward way of evaluating models by removing much of the contribution of internal variability, revealing model successes and biases. The results demonstrate the importance of atmospheric circulation in driving interannual variability in sea ice and near-surface air temperatures, particularly in the summer. Finally, we will discuss the potential role of ocean surface waves in driving variability in Arctic sea ice, based on observational analysis and new coupled modelling results.
Denoising of river surface photogrammetric DEMs using deep learning
Authors: Szostak Radosław , Wachniew Przemysław , Zimnoch Mirosław , Ćwiąkała Paweł , Puniach Edyta , Pietroń Marcin
Published: March 2021

Unmanned Aerial Vehicles (UAVs) can be an excellent tool for environmental measurements due to their ability to reach inaccessible places and fast data acquisition over large areas. In particular drones may have a potential application in hydrology, as they can be used to create photogrammetric digital elevation models (DEM) of the terrain allowing to obtain high resolution spatial distribution of water level in the river to be fed into hydrological models. Nevertheless, photogrammetric algorithms generate distortions on the DEM at the water bodies. This is due to light penetration below the water surface and the lack of static characteristic points on water surface that can be distinguished by the photogrammetric algorithm. The correction of these disturbances could be achieved by applying deep learning methods. For this purpose, it is necessary to build a training dataset containing DEMs before and after water surfaces denoising. A method has been developed to prepare such a dataset. It is divided into several stages. In the first step a photogrammetric surveys and geodetic water level measurements are performed. The second one includes generation of DEMs and orthomosaics using photogrammetric software. Finally in the last one the interpolation of the measured water levels is done to obtain a plane of the water surface and apply it to the DEMs to correct the distortion. The resulting dataset was used to train deep learning model based on convolutional neural networks. The proposed method has been validated on observation data representing part of Kocinka river catchment located in the central Poland.

This research has been partly supported by the Ministry of Science and Higher Education Project “Initiative for Excellence – Research University” and Ministry of Science and Higher Education subsidy, project no. 16.16.220.842-B02 / 16.16.150.545.
Spatial-temporal migration of the central-southern Apennine belt and foreland basin system (Italy) constrained by Sr-isotope stratigraphy
Authors: Sabbatino Monia , Tavani Stefano , Vitale Stefano , Corradetti Amerigo , Consorti Lorenzo , Parente Mariano
Published: March 2021

The Apennines form an active fold and thrust belt that develops as part of the W-Mediterranean subduction zone. The evolution of the collisional system is driven by the retreating subduction of the alpine Tethys, which has caused the migration of compressive fronts and the opening of the Liguro-Provençal and Tyrrhenian back-arc basins, along with the rotation and translation of the Sardinia-Corsica and Calabria blocks. The Apennines make the northern limb of the Apennines-Calabria-Sicily orocline, developed due to the differential SE-ward retreat of the subduction system. In such a context, the central-southern Apennine system develops a foreland basin floored by a subaerial forebulge unconformity followed by a trinity of diachronous lithostratigraphic units: (i) shallow-water carbonates, (ii) hemipelagic marls, and (iii) siliciclastic turbidites. Previous studies have used the following datasets for reconstructing the evolution of the orogenic-foreland basin system: paleomagnetic data;  the age of the siliciclastic syn-orogenic deposits filling the foredeep and wedge-top depozones; the age of the late-orogenic extensional basins. In this study, we highlight the importance of dating with high precision the onset of the Apennine orogenesis by means of Sr-isotope stratigraphy applied to the first carbonate sediments overlying the forebulge unconformity. In this regard, we have investigated a transect of the Apennine belt, extending from inner to outer sectors, in order to constrain the timing and style of migration of the belt and foreland basin. Our results show progressive rejuvenation of the forebulge unconformity toward the outer portions of the belt. More importantly, we highlight a time delay between the onset of syn-orogenic shallow-water carbonate deposition and the onset of siliciclastic turbidite deposition that ranges between 1 and 11 myr. In detail, the trends in the delay point at three main evolutive steps: 1) rapid evolution from forebulge to foredeep during the Burdigalian, 2) higher delays from the Serravallian until the latest Miocene, and 3) progressive decrease of the delay from the Zanclean. We associate the different velocity of migration with the differential slab retreat and spreading of the back-arc basins.
Modeling tippers on a sphere
Authors: Kuvshinov Alexey , Kruglyakov Mikhail
Published: March 2021

In the past three decades, a huge amount of long-period magnetic data (from weeks to years of measurements) has been collected around the world either inland or at sea bottom. It makes tempting to estimate from these data magnetotelluric (MT) vertical transfer functions - tippers – in as wide  period range as practicable and further probe with them the three-dimensional (3-D) distribution of electrical conductivity in the upper mantle on a global or semi-global/continental scale. Such problem setup requires modelling MT responses in spherical geometry. It is known that MT impedances in spherical coordinates can be modelled using different polarizations of a uniform external magnetic field. As for tippers, one cannot compute them on a sphere using this type of excitation, because the uniform external magnetic field of any polarization contains a non-zero vertical component. To overcome the problem, we elaborate a model of the source, which leads to valid MT tippers on a sphere or a part thereof. To compute tippers in spherical Earth models with 3-D conductivity distribution we use a novel accurate and computationally efficient solver called GEMMIE. The solver is based on nested integral equations, allowing researchers to calculate high-resolution MT tippers globally and regionally taking into account realistic oceans, sediments, and Earth’s conductivity.
Developing a Wildfire danger index based on the satellite-derived parameters 
Authors: Babu Suresh , Visser Vernon , Moncrieff Glenn , Slingsby Jasper , Altwegg Res
Published: March 2021

Wildfires are occurring throughout the world, causing immense damage to forest resources, flora, and fauna. The Fire Danger indices are used as a tool for the decision-makers to issue warnings to the public, based on the level of fire danger classes for implementing mitigation measures to control wildfires. In this study, a Wildfire danger index (WDI) is developed from static and dynamic factors, which are derived from satellite datasets. The Static fire danger Index (SFDI) is generated using MODIS Land cover type (MCD12Q1), Shuttle Radar Topography Mission (SRTM) DEM, and Open Street Map datasets. The Random Forest algorithm is used to generate SFDI from the parameters LULC map, slope map, aspect map, and elevation maps based on the historical MODIS active thermal anomaly product (MCD14). Dynamic Fire Danger Index (DFDI) is developed from the MODIS Terra datasets such as Land Surface Temperature (MOD11A2) and surface reflectance (MOD09A1) datasets.  The DFDI is developed from four parameters viz. Land surface temperature, Visible Atmospherically Resistant Index (VARI) and Normalized Multiband Drought Index (NMDI), and Normalized Difference Infrared Index – B6 (NDIIB6). Finally, the wildfire danger index is calculated by integrating SFDI and DFDI and found that the accuracy is more than 80% during the 2018-19 fire season. Therefore, the WDI can be useful for disseminating daily fire danger maps on near real-time basis using the MODIS TERRA Near Real-Time datasets so that the fire officials to take necessary actions to control the spread of wildfires.

 

 

 
The response of a fractured crystalline reservoir to natural pressure buildup: Experiment results from the Bedretto Lab
Authors: Shakas Alexis , Gholizadeh Nima , Hertrich Marian , Wenning Quinn , Maurer Hansruedi , Brixel Bernard , Zappone Alba , Rinaldi Antonio , Obermann Anne , Ma Xiaodong , Kaestli Philipp , Linwood Paul , Hochreutener Rebecca , Wiemer Stefan , Giardini Domenico
Published: March 2021

The Bedretto Underground Laboratory for Geosciences and GeoEnergies, located in the Swiss Alps and situated under more than 1 km of granitic overburden, offers a unique field site to study processes in fractured rock. Currently, a total of six boreholes are available, four of them being permanently instrumented with monitoring equipment, and two dedicated as stimulation boreholes. One of the monitoring boreholes contains permanent packed-off intervals which record pressure changes and flow rate. The remaining three are instrumented with a variety of sensors, including fiber-optic micro-strain sensors, temperature monitoring, permanent geophones and accelerometers. All monitoring boreholes are either sealed with packers or cemented, and only the stimulation boreholes allow for outflow. During a period of several weeks, we were able to seal the two stimulation boreholes and allow the reservoir to approach ambient pressure conditions (more than 3 MPa at the wellhead) while we monitored the response of the reservoir. The pressure buildup shows not only in the pressure data, but also as stress changes in the reservoir. During a depressurization phase, we quickly opened one borehole and subsequently performed time-lapse single-hole Ground Penetrating Radar (GPR) measurements. At a second depressurization phase, we continued the GPR measurements while opening the second borehole in a controlled manner. The changes in strain, pressure and GPR reflectivity illuminate the response of the reservoir when moving from ambient to atmospheric pressure at the wellhead, and reveal processes such as wellbore storage, pore-pressure variations and ultimately permeability changes in the reservoir.
Quantitative evaluation of soil functions: application to the data of the German Agricultural Soil Inventory
Authors: Wollschläger Ute , Don Axel , Poeplau Christopher , Weller Ulrich , Wiesmeier Martin , Vogel Hans-Jörg
Published: March 2021

The quantitative evaluation of the impact of agricultural management and climate change on soil functions is prerequisite for developing sustainable soil management. Soil functions are integral properties emerging from complex process interactions. They cannot be measured directly so that we need to rely on evaluation schemes based on indicators.

Vogel et al. (2019) developed a scheme to quantitatively evaluate soil functions which distinguishes between a soil’s potential and its actual state. They defined a soil’s potential to provide a soil function to be the maximum a soil can offer based on its inherent properties and site conditions while assuming that all soil properties that can be affected by soil management are in some optimum state within the limits of good agricultural practice. In contrast, a soil’s state is evaluated based on its manageable soil attributes. It can be applied to describe the room for improvement.

In this presentation, we apply the evaluation scheme by Vogel et al. (2019) at the scale of Germany using the data from the German Agricultural Soil Inventory (Jacobs et al., 2018; Poeplau et al., 2020). We use the data from more than 2200 soil profiles from arable sites and calculate indicators for potentials and actual states for the production function, the carbon storage function and the water storage function. For all functions, results show characteristic patterns which can be related to climatic and soil conditions but also provide evidence about the influence of agricultural management on soil functions. The results of this study may be used to analyze synergies and trade-offs between the various soil functions and to develop options for more sustainable soil management.

 

References:

Jacobs, A., Flessa, H., Don, A., Heidkamp, A., Prietz, R., Dechow, R., et al. (2018). Landwirtschaftlich genutzte Böden in Deutschland - Ergebnisse der Bodenzustandserhebung. doi:10.3220/REP1542818391000.

Poeplau, C., Don, A., Flessa, H., Heidkamp, A., Jacobs, A., and Prietz, R. (2020). Erste Bodenzustandserhebung Landwirtschaft -- Kerndatensatz. doi:10.3220/DATA20200203151139.

Vogel, H.-J., Eberhardt, E., Franko, U., Lang, B., Ließ, M., Weller, U., et al. (2019). Quantitative Evaluation of Soil Functions: Potential and State. Front. Environ. Sci. 7, 164. doi:10.3389/fenvs.2019.00164.
Decline of the Arctic 'ice factories' delayed by negative feedbacks
Authors: Cornish Sam , Johnson Helen , Richards Alice , Kostov Yavor , Dörr Jakob
Published: March 2021

Over the past few decades, Arctic sea ice volume has been decreasing faster in summer than winter; winter sea ice growth has been increasing, helping to restore the ice pack, despite the fact that Arctic warming is most intense in the winter. This raises the questions: why? And for how long can we expect winter ice growth to keep increasing? We pose these questions with a regional focus on the Kara and Laptev seas. These seas are often termed the ice factories of the Arctic because of their outsized contributions to the Arctic sea ice budget, a consequence of their divergent settings. Using the CESM climate model ensemble, we separate out the influence of different levers on ice factory productivity (the ice growth rate), and show that 20th Century and RCP8.5 changes can be skilfully reconstructed by a linear model incorporating 2 m temperature, snow thickness, September sea ice area, total (gross) divergence and ice export. Ocean temperatures, meanwhile, help to explain the timing of the onset of freezing. Increasing air temperatures naturally decrease the growth rate, while positive contributions to growth rate are made by a decreasing September sea ice area, increasing divergence and increasing export. These positive influences are all associated with a thinning, more mobile ice pack: they are negative feedbacks on sea ice loss. In CESM, once the September sea ice area in the Kara-Laptev seas approaches zero, the year-on-year productivity of the ice factories starts to decline. We place these results in the context of observations and discuss the prospects for the productivity of the Arctic Ocean’s ice factories.
Integrating multibeam echosounder water-column data into benthic habitat mapping
Authors: Porskamp Peter , Schimel Alexandre , Young Mary , Rattray Alex , Ladroit Yoann , Ierodiaconou Daniel
Published: March 2021

Kelp forests worldwide are under ever increasing pressure from anthropogenic impacts including kelp harvesting, pollution, and higher sea surface temperatures due to climate change. Marine spatial planning requires accurate mapping of these habitat types to inform effective policy. Key data needed for benthic habitat maps to inform policy are acquired by multibeam echosounders, which collect high resolution bathymetry and backscatter of the seafloor. An additional and previously little used product of high resolution MBES are mid-water backscatter data, termed water-column data, that have been used to identify and map kelp species that extended above the seafloor. We show that incorporating water-column data as a variable for modeling benthic marine habitat distributions can significantly improve the accuracy of benthic habitat maps, specifically where habitat categories include large species of macroalgae on shallow (2-34m) subtidal reefs. The study site has full coverage multibeam bathymetry, backscatter and water-column data, alongside comprehensive observation surveys of benthic habitats using towed video. All towed video observations were classified using a hierarchal marine biotope classification scheme. Water-column data were processed into a mosaic-like product representing the acoustic energy in a layer 0-1m above the seabed. This processing included filtering of the sidelobe artefact. The volumetric water-column mosaic along with bathymetric and backscatter derivatives combined with towed video observations were used as input variables in a supervised random forest classification algorithm to create habitat maps for the study site. Variable importance was assessed for all variables and water-column performed well as it was retained in all models. Including water-column data increased overall map accuracy up to 1.18% and improved producer class accuracies that contained macroalgae up to 2.95%. With increasing pressure on temperate macroalgal communities due to a synergy of pressures arising from warming oceans, our work provides a timely advance for mapping and monitoring changes.
State of the Art in Cup Anemometry
Authors: S. Pirooz Amir A. , Flay Richard G.J. , Turner Richard , Azorin-Molina Cesar
Published: March 2021

Despite the great development of more accurate and sophisticated wind-measurement instruments, cup anemometers remain today the most widely used and popular anemometer in measuring wind speeds at meteorological stations and wind farms. In addition, almost all the available long-term wind speed time series across the world have been recorded by cup anemometers. Studying the response of cup anemometers and errors associated with their measurements, and also how the cup anemometer measurements are comparable with modern sensors, is of great importance, and can affect meteorological and climatological studies of long-term wind speed trends, and also wind energy estimations. 

Although cup anemometers are known for being robust and reliable, long-term field measurements of wind speeds by these wind sensors can be associated with errors and uncertainties affecting the quality of recorded data and subsequent analyses. When analysing wind speed data, it is essential to understand these errors and compensate for them and distinguish them from the real climate signals.

A comprehensive review on various aspects of anemometry, particularly cup anemometers, is presented in this paper. This review includes the different designs and theory developed from the invention of this wind-speed measuring system to very recent works, the response characteristics of anemometers, anemometer calibration procedures, field and wind-tunnel experiments on anemometers, etc. In addition, the different sources of errors and uncertainties are introduced and methods, including statistical, mathematical and experimental approaches, proposed to quantify and remedy the effects of these errors are presented. Lastly, several comparative studies that investigated the response characteristics of different types of cup anemometers and other anemometers are reviewed.
A Model for Coronal Inflows and In/Out Pairs
Authors: Lynch Benjamin
Published: March 2021

We present a three-dimensional (3D) numerical magnetohydrodynamics (MHD) model of the white-light coronagraph observational phenomena known as coronal inflows and in/out pairs. Coronal inflows in the LASCO/C2 field of view (approximately 2–6 Rs) were thought to arise from the dynamic and intermittent release of solar wind plasma associated with the helmet streamer belt as the counterpart to outward-propagating streamer blobs, formed by magnetic reconnection. The MHD simulation results show relatively narrow lanes of density depletion form high in the corona and propagate inward with sinuous motion that has been characterized as "tadpole-like" in coronagraph imagery. The height–time evolution and velocity profiles of the simulation inflows and in/out pairs are compared to their corresponding observations and a detailed analysis of the underlying magnetic field structure associated with the synthetic white-light and mass density evolution is presented. Understanding the physical origin of this structured component of the slow solar wind’s intrinsic variability could make a significant contribution to solar wind modeling and the interpretation of remote and in situ observations from Parker Solar Probe and Solar Orbiter.
Interannual Variability in Global Ocean Mass Derived from 18+ Years of GRACE and GRACE-FO Satellite Gravimetry
Authors: Gutknecht Benjamin D. , Groh Andreas , Horwath Martin
Published: March 2021

The combined 18+ years long time series of observations of the Earth's gravity field from the satellite missions GRACE and GRACE-FO provides us with an unprecedented opportunity to analyse mass change and re-distribution in the Earth system. Furthermore, as the mission continues, we may also gain more insight into those types of variability in the water mass system that act over time scales of several years and possibly even decades.

For our analysis presented here, we updated the previous Ocean Mass Change (OMC) product by the ESA CCI Sea Level Budget Closure project, including (1) corrections for Glacial Isostatic Adjustment, (2) restorement of GAD background fields, (3) subtraction of atmospheric mean fields, and (4) replacement of dedicated low-degree coefficients for centre-of-mass, oblateness (TN14) and C30 (TN14) in the spherical harmonic gravity field solutions. We applied least-squares minimisation of the residual of a multi-parameter functional fit to the OMC series, including i.a. linear trend, semi-/annual signals, and an optional quadratic fit. We analysed the complete residual series based on the four monthly GRACE and GRACE-FO RL06 solutions from CSR/GFZ/JPL and ITSG-Grace2018 after removal of linear trend and seasonal cycles.

The remaining signal shows clear evidence of interannual oscillations and correlates (>0.5) with the Multivariate ENSO index (MEI). By spectral analysis and by an independent simulated-annealing approach, we locate several primary modes of the residual between 130 and 29 months. The phase of the lowest of these partial frequencies approximates that of solar flux data representing the solar cycle and the shortest major mode resembles the frequency of the Quasi Biennial Oscillation. However, minor phase-shifts and a direct physical link in this regard are not yet fully understood. When we include the extra modes in our OMC minimisation approach, it can be shown that recent acceleration in global ocean mass may indeed be smaller than previously anticipated by quadratic fitting while neglecting longer wavelengths.

Furthermore, the extrapolation of the fit including three prominent interannual modes between 29 and 130 months is able to predict recent La Niña related negative ocean mass anomalies. Our findings might support and integrate in similar analyses of the global sea level and other ECVs elsewhere. However, we must emphasise that an analysis of near-decadal oscillations from a sub-20 year lasting data set is yet to become more stable with increasing observation length from GRACE-FO.
Semi-automated quantification of Ice Rafted Debris in sediment archives with Computed Tomography.
Authors: Cederstrøm Jan Magne , Rutledal Sunniva , Støren Eivind W. N. , van der Bilt Willem G. M.
Published: March 2021

Ice rafted debris (IRD) in marine sedimentary sequences provide critical information about the evolution of ice sheets. These include enigmatic phases of ice sheet instability like Heinrich events, Dansgaard-Oeschger cycles or Bond events. Higher sampling resolution and greater spatial coverage in IRD records can help gain a better understanding of paleoaclimate, and help predict the future behavior of ice sheets. However, creating high-resolution IRD-records from marine sediment cores is a manual time- and labor-intensive laboratory procedure. By allowing for rapid and non-destructive quantification of micrometer (µm) scale particles, Computed Tomography (CT) holds the potential to increase both resolution and the pace of analysis. We demonstrate the potential of this approach with results from both experimental results and application on conventionally analyzed records. By using basic image processing tools on CT-imagery of phantom-boxes (replicating marine sediment cores with IRD) we counted sand-particles (>150 µm) of different mineralogies ranging from 25-2000 particles/g. The CT-results proved to match the manual counts with a r2 of up to 0.99 and a P-value of 0.00. Further, when applying the method on segments of natural marine sediment cores with published IRD-records, we were able to reconstruct the same trends as continuous counts with a 5 times higher spatial resolution. In addition, this non-destructive method gave further information on the impact of bioturbation, grainsize distribution and the sedimentary structure of IRD-deposits. In conclusion, this work can help the field to gain an even better understanding of the behavior of ice sheets by optimizing the efficiency and spatial resolution of IRD-records, while at the same time gaining a better understanding on the processes affecting the IRD-deposits.
Digital pedogenon mapping as basis for assessing changes in soil condition
Authors: Roman Dobarco Mercedes , McBratney Alex , Minasny Budiman , Malone Brendan
Published: March 2021

The response of soils to different human forcings may vary among soil classes (in magnitude and direction of change) depending on their resistance and resilience. We propose a modelling framework for mapping soil-class specific references (i.e., genosoils) and their variants (i.e., phenosoils) that can be used for assessing changes in soil condition due to land use change and management practices. The methodology consists of a first step that creates groups characterized by homogeneous soil-forming factors for a given reference time, under the hypothesis that these groups represent soil classes resulting from multimillennial natural pedogenesis and historic anthropedogenesis (i.e., soil formation processes modified by human activities) (i.e., pedogenons). In this study we applied the methodology to New South Wales (Australia) at the time of the European settlement, because from 1788 onwards the intensification of land use may have accelerated the rate of change of soil properties. A thousand pedogenon classes were generated applying k-means clustering to a set of quantitative state variables that represent the soil-forming factors at the time of the European settlement. Hierarchical clustering was applied to the centroids of the pedogenon classes for assessing their similarities and organization. In a second step, information on native vegetation extent, status (cleared or intact), and current land use was combined for creating a categorical map distinguishing areas with different expected degree of human-induced soil change. The combination of both maps resulted in 5448 subclasses, ranging from remnant genosoils (located in protected areas of intact native vegetation), genosoils II, cleared, grazing and cropping phenosoils. For each pedogenon there was at least a 90-m grid cell classified as a remnant genosoil. The median of the proportion of the pedogenon of origin preserved as a remnant genosoil was 5.3%. Phenosoils grazing and cropping occupied larger areas, with mean values of 73 km2 and 153 km2 respectively. Finally, we tested differences in topsoil pH, as proxy for soil condition, by genosoil and phenosoil classes using legacy soil data accessed with the Soil Data Federator from the Terrestrial Ecosystem Research Network. A gls model indicated that the effects of pedogenon, genosoil/phenosoil and their interaction were statistically significant (p < 0.001). Paired mean comparisons suggested that mean pH did not differ between remnant genosoils and genosoil II, but the mean pH of both genosoil classes differed from phenosoils. Estimated pH means did not differ between phenosoil classes, although it followed the trend remnant genosoil < genosoil II < phenosoil cleared < phenosoil grazing < phenosoil cropping. The proposed methodology has several potential applications, including soil security and soil change assessment, and designing soil monitoring surveys.
Local and non-local climatic impacts of land use across scales
Authors: Chen Liang
Published: March 2021

It has been widely recognized that land use/land cover changes have great potential to influence climate at different scales. However, their local and non-local impacts have not been well understood. First, previous studies are limited by the assumption that the local impacts of land use do not modify the atmospheric background states. Second, land-use impacts may vary if simulations are conducted at a different spatial scale. In this study, we investigate the local and non-local impacts of historical land use using the Community Earth System Model version 2, and explore the possible influence of model resolutions on the local and non-local impacts. The local and non-local impacts of land use are separated using atmospheric nudging, in which the horizontal winds in the upper atmosphere are forced to follow the ERA-Interim reanalysis, whereas the nudging strength is zero at the surface. The multi-resolution experiments suggest that the local impacts of land use are consistent at different spatial scales, but the non-local impacts are influenced by the model resolution. We will also discuss the local and non-local impacts of land use on climate extremes across scales. This study presents a new way to distinguish the local and non-local impacts and highlights the uncertainty in simulated land-use impact in climate studies. 
The relationship between the El Niño Southern Oscillation and Australian monsoon rainfall on decadal time-scales
Authors: Heidemann Hanna , Ribbe Joachim , Henley Benjamin J. , Cowan Tim , Pudmenzky Christa , Stone Roger , Cobon David H.
Published: March 2021

This research analyses the observed relationship between eastern and central Pacific El Niño Southern Oscillation (ENSO) events and Australian monsoon rainfall (AUMR) on a decadal timescale during the December to March monsoon months. To assess the decadal influence of the different flavours of ENSO on the AUMR, we focus on the phases of the Interdecadal Pacific Oscillation (IPO) over the period 1920 to 2020.  The AUMR is characterized by substantial decadal variability, which appears to be linked to the positive and negative phases of the IPO. During the past two historical negative IPO phases, significant correlations have been observed between central Pacific sea surface temperature (SST) anomalies and AUMR over both the northeast and northwest of Australia. This central Pacific SST-AUMR relationship has strengthened from the first negative IPO phase (mid-1940s to the mid-1970s) to the second (late 1990s to mid-2010s), while the eastern Pacific SST-AUMR influence has weakened. Composite rainfall anomalies over Australia reveal a different response of AUMR to central Pacific El Niño/La Niña and eastern Pacific La Niña events during positive IPO and negative IPO phases. This research clearly shows that ENSO's influence on AUMR is modulated by Pacific decadal variability, however this teleconnection, in itself, can change between similar decadal Pacific states.  Going forward, as decadal prediction systems improve and become more mainstream, the IPO phase could be used as a potential source for decadal predictability of the tendency of AUMR.  
Thunderstorms in Corsica Island measured during the EXAEDRE aircraft campaign
Authors: Lee Keunok , Defer Eric , Combarnous Pauline , Pinty Jean-Pierre , Buguet Magalie , Caumont Olivier , Delanoë Julien , Jaffeux Louis , Pedeboy Stéphane , Prieur Serge , Richard Evelyne , Schwarzenboeck Alfons
Published: March 2021

The aim of this study is to enhance our understanding about the microphysical structure of convective cloud systems and its relationships to the ambient electrical field, and to assess the capability of a model to capture the cloud electrical properties. This study relies on the EXAEDRE (EXploiting new Atmospheric Electricity Data for Research and the Environment) aircraft campaign that took place from 13 September to 8 October 2018 in Corsica Island. Eight electrified convective systems were successfully sampled during the campaign by the French Falcon 20 aircraft (e.g. RASTA Doppler cloud radar, microphysics probes, electric field mills) and ground-based platforms (Lightning Mapping Array network, Météorage operational lightning locating system and Météo-France weather radars). In this study, a multi-cell thunderstorm which developed over the complex topography of Corsica Island on 17 September 2018 was selected to investigate and to understand the physical processes linking lightning occurrence, electrification efficiency, cloud microphysics and dynamics. The detailed analysis results using the unprecedented airborne and ground-based dataset and their comparison to the numerical simulation results with a horizontal grid spacing of 1 km comprising the explicit electrical scheme CELLS (Cloud Electrification and Lightning Scheme) implemented in the cloud resolving model Meso-NH has been conducted. The key results will be presented at the conference.
Observations Inform Improvements in Model Silicon Cycling in a Semi-enclosed Coastal Sea
Authors: Olson Elise , Nemcek Nina , Allen Susan
Published: March 2021

We have developed a coupled physical-biological model representing plankton and nutrient dynamics of the Strait of Georgia, a fjord-like semi-enclosed coastal sea on the west coast of Canada. The nutrient-phytoplankton-zooplankton-detritus (NPZD)-type biological model is based on nitrogen uptake and remineralization with a coupled silicon cycle and includes both diatom and non-siliceous phytoplankton functional groups. The Strait of Georgia exhibits an estuarine circulation driven by input from the Fraser River as well as many smaller rivers and streams. It has high levels of dissolved silica (can be >50 μM even at the surface). Silicon-replete conditions shape key characteristics of the local ecosystem, which include heavily silicified glass sponge reefs as well as frequent diatom and occasional silicoflagellate blooms. We therefore consider the ability of the model to match observed silicon levels an indicator of the fidelity of its representation of local biogeochemistry. Silicon in the model may be in the form of dissolved silica, living diatoms, or particulate biogenic silica, and model diatom growth may be limited by nitrogen, light, or dissolved silica availability. We will discuss the challenges involved in accurately representing important drivers of the regional silicon cycle. These include accurately capturing the division of primary productivity between diatoms and non-siliceous phytoplankton functional groups, as well as uncertainties in the magnitude of terrestrial inputs and sediment fluxes. We will show how evaluating the model functional groups by comparison with phytoplankton community composition determined by high performance liquid chromatography (HPLC) has informed our interpretation of model results and provided direction for efforts at improving model performance. We will discuss the impact of targeted adjustments to model parameters on the model silicon cycle in light of comparisons to observations.
Nonlinear long-period tidal forcing with application to ENSO, QBO, and Chandler wobble
Authors: Pukite Paul
Published: March 2021

Apart from its known impact to variations in the Earth’s length-of-day (LOD) variations, the role of long-period tidal forcing cycles in geophysical behaviours has remained elusive. To explore this further, tidal forcing is considered as a causative mechanisms to the following cyclic processes: El Niño Southern Oscillation (ENSO), Quasi-Biennial Oscillation (QBO), and the Chandler wobble. Annualized impulse reponse formulations and nonlinear solutions to Navier-Stokes-based Laplace's Tidal Equations  are required to make the connection to the observed patterns as the underlying periods are not strictly commensurate in relation to harmonics of the tidal cycles.  If equatorial climate phenomena such as QBO and ENSO can be explained as deterministic processes then the behavior that may be predictable. This paper suggests that QBO, ENSO, and the Chandler wobble may share a common origin of lunar and solar tidal forcing, but with differences arising due to global symmetry considerations. Through analytical approximations of nonlinear fluid dynamics and detailed time-series analysis, matching quantitative models of these behaviors can be shown.
Insights into seismic activity of Central Adriatic offshore (Italy) evidenced by the 2013-2014, Conero seismic sequence
Authors: Adinolfi Guido Maria , Battimelli Elvira , Amoroso Ortensia , Capuano Paolo
Published: March 2021

The Adriatic region has always attracted the interests of researchers involved in the study of the tectonic processes that controlled the evolution of the Alpine-Mediterranean area. It has been considered as an undeformed area, an aseismic, rigid block located between two active orogenic belts, the Apennines and External Dinarides thrust belts. Nevertheless, new scientific evidences reveal a complex structural framework in which active faults are capable to produce seismic activity not only along the borders of Adriatic Sea, but also in the offshore areas. In fact, the outer thrusts of Apennines and Dinarides orogenic belts propagated from the coasts to the offshore areas originating active, NW-SE trending anticlines and thrust faults that affects the Plio-Quaternary sequences.

Defining the seismotectonics of Adriatic domain and studying the active tectonics of the area with its seismogenic potential represent a challenge because the sea prevents direct observation of main geological and structural lineaments and the deployment of standard seismic networks for a more accurate analysis of seismicity. Despite the existence of new evidences, derived from seismic profiles and borehole data, by hydrocarbon exploration, correct seismic hazard estimates of Adriatic Sea require original and accurate data on the seismic activity that can allow to depict the number, size and geometry of seismogenic sources.

In this work, we focused our attention on the seismic sequence, consisting of about 230 events,  which occurred along the Central Adriatic coast, in the Conero offshore, during the 2013-2104, with a ML 4.9 mainshock located at 20 km far away from city of Ancona, the main city of Marche region. After a careful and innovative selection of the data recorded from the Italian National Seismic Network, operated by the Istituto Nazionale di Geofisica e Vulcanologia, the earthquakes were relocated according to a probabilistic approach. By the inversion of the polarity of the P-wave first arrivals, the focal mechanisms were estimated and finally the local magnitudes were re-calculated. Moreover, in order verify if there has been a migration of seismicity with the activation of different faults during the seismic sequence, the analysis of spatio-temporal evolution of the seismic sequence was performed. Preliminary results show that the seismic sequence was originated mainly at small depths (< 10 km) along NW-SE trending thrust fault structures as evidenced by fault plane solutions, consistent with NE-SW horizontal, maximum compression of the outer front of Apennines thrust belt, still active in the Central Adriatic offshore.
Exploring the atmospheric sulfur trends and the potential contribution of sulfate-reducing microorganism activities to the atmospheric sulfur budget at Saturna Island, B.C
Authors: mostafaei mona , Norman Ann-Lise , Mohamed Fwziah
Published: March 2021

Anthropogenic and biogenic activities, along with the fluxes of sea salt, volcanic, wildfire and oceanic sulfate-reducing microorganisms (SRM), contribute significantly to the atmospheric sulfur budget.(1,2)

There is still uncertainty and debate between studies about the magnitude of the importance of oceanic hydrogen sulfide (H2S) produced by SRM, as well as its ability to diffuse to the upper water column and its contribution to the atmospheric sulfur budget. While some studies believe that the majority of H2S is re-oxidized and is less likely to reach the atmosphere (3,4), there is evidence of the existence of H2S in the upper water columns and even in the atmosphere (2,5). H2S produced by SRM, emitted to the atmosphere, along with the anthropogenic sulfur dioxide (SO2) and dimethyl sulfide (DMS), undergo atmospheric oxidation processes. Sulfate (SO42-), as one of the main oxidized products, may nucleate with water vapor, ammonia and organic oxides (6,7), and subsequently grow to bigger particle sizes. These particles affect the climate directly and indirectly and change the radiation balance of the Earth-atmosphere system. (8,9,10)

This study assessed the seasonal trends of major atmospheric sulfur species including SO2, sulfate, and biogenic and anthropogenic sulfate of gas, aerosol and precipitation samples, collected by Canadian Air and Precipitation Monitoring Network (CAPMoN), Environment of Canada, at Saturna Island, B.C, between 1998-2010. We then explored the oceanic phytoplankton activities and DMS production, based on sulfur isotope composition and found the importance of DMS contribution to the summertime atmospheric sulfur budget. A handful of samples (~10-30%) displayed negative sulfur isotope compositions, outside the range of anthropogenic and biogenic isotope values. Potential factors that could produce such negative sulfur isotope composition values include isotopic fractionation, fluxes from mineral dust events, volcanic eruptions, wildfires and microbial sulfate reduction (MSR). Our study found that MSR was the only feasible explanation for these very negative sulfur isotope compositions in non-sea salt sulfate samples. H2S in our study was a 4th potential contributor to the atmospheric sulfur budget, along with the 3 major sources of anthropogenic, biogenic DMS, and sea-salt sulfate, in this long-term atmospheric sulfur study.

 