bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of Contribution to PM2.5 from Ship Emissions over Korea
Authors: Seo Jihyun , Moon Nankyoung
Published: March 2020

In order to manage fine particulate matter, class 1 carcinogen, various policies are being prepared by the government. The government announced a set a policy measures to confront pollution issues in November 2019. Diesel cars classified as grade 5 will be banned and maximum 27 coal power plants would be plugged off from December to March when fine particulate matter usually worsen to curtail air pollution by more than 20 percent. Despite such efforts, however, it is difficult to improve the concentration of fine particulate matter. In particular, as fine particulate matter management policies are biased toward the management of coal power plants or diesel cars, port and ship emissions management are relatively insufficient.

In the case of major Korea’s port cities such as Busan and Incheon, the impacts of fine particulate matter from ship emissions are analyzed to be significant. In particular, the use of low-grade fuel such as bunker C oil, which has high sulfur content, generates a large amount of fine particulate matter and other air pollutants. As such, for fine particulate matter management in port areas, the impact of ships, cargo handling equipment and cargo trucks, which are major sources of emissions, needs to be quantitatively understood.

Under this background, the emission characteristics of ship emissions were identified by using national air pollutants emissions data in 2015, which improved the calculation method of ship emission sources and the contribution concentration of PM2.5 was analyzed using WRF and CMAQ/BFM. The modelling period is one year in 2016, and the resolution of 9km modeling was applied to Korea.

As one of the main results, the annual mean PM2.5 contribution concentration from domestic ship emission sources was analyzed to be 0.57μg/㎥, and the PM2.5 contribution concentration by local governments was calculated to be most affected by the 1.39μg/㎥ in Busan. The results of this study have not taken into account additional sources of emissions such as cargo handling equipment and cargo trucks using ports, and if this is taken into account, the actual contribution concentration of PM2.5 in port areas is expected to be higher.

The results of this research can be used as basic data when establishing policies for reducing fine particulate matter by major emission sources by local governments.
Reconciling the BDC response in climate models to the volcanic forcings with reanalyses
Authors: Diallo Mohamadou , Garny Hella , Eichinger Roland , Aquila Valentina , Ern Manfred , Ploeger Felix
Published: March 2020

The stratospheric Brewer--Dobson circulation (BDC) is an important element of climate system as it determines the concentration of radiatively active trace gases like water vapor, ozone and aerosol above the tropopause. Climate models predict that increasing greenhouse gas levels speed up the stratospheric circulation. BDC changes is substantially modulated by different modes of climate variability (QBO, ENSO, solar cycle), including the volcanic aerosols. However, such variability is often not reliably included or represented in current climate model simulations, challenging the evaluation of models’ behavior against observations and constituting a major uncertainty in current climate simulations. 

Here, we investigate the main differences between the reanalysis and the CCMI/CMIP6 climate models’ response to stratospheric volcanic forcings regarding the depth/strength of the stratospheric BDC, with a focus on potential changes in the deep and shallow circulation branches. We also discuss the key reasons of the discrepancies (incl. uncertainties associated with volcanological forcing datasets and missing direct aerosol heating in the reanalysis) in the BDC response between reanalysis-driven and climate model simulations in the lower, mid and upper stratosphere. Finally, we assess the dynamical mechanisms involved in the volcanically-induced BDC changes to understand the opposite regime between lower, middle and upper stratosphere after the Mt Pinatubo eruption.
Toward high precision XCO2 retrievals from TanSat observations
Authors: Boesch Hartmut , Yang Dongxu , Liu Yi , Somkuti Peter
Published: March 2020

TanSat is the 1st Chinese carbon dioxide measurement satellite, launched in 2016. Preliminary TanSat XCO2 retrievals have been introduced in previous studies based on the 1.6 m weak CO2 band. In this study, the University of Leicester Full Physics (UoL-FP) algorithm is implemented for TanSat nadir mode XCO2 retrievals. We develop a spectrum correction method to reduce the retrieval errors by an online fitting of an 8th order Fourier series. The model and a priori is developed by analyzing the solar calibration measurement. This correction provides a significant improvement to the O2 A band retrieval. Accordingly, we extend the previous TanSat single CO2 weak band retrieval to a combined O2 A and CO2 weak band retrieval. A Genetic Algorithm (GA) has been applied to determine the threshold values of post-screening filters. In total, 18.3% of the retrieved data is identified as high quality compared. The same quality control parameters have been used in the bias correction due to the stronger correlation with the XCO2 retrieval error. A footprint independent multiple linear regression is applied to determine the sounding XCO2 retrieval error and bias correction. Twenty sites of the Total Column Carbon Observing Network (TCCON) have been selected to validate our new approach of the TanSat XCO2 retrieval. We show that our new approach produces a significant improvement of the XCO2 retrieval accuracy and precision when compared with TCCON with an average bias and RMSE of -0.08 and 1.47 ppm respectively. The methods used in this study, such as continuum correction, can help to improve the XCO2 retrieval from TanSat and subsequently the Level-2 data production, and hence will be applied in the TanSat operational XCO2 processing.
Photogrammetricaly measured sheet and rill erosion on steep slopes
Authors: Laburda Tomas , Kavka Petr , Kubínová Romana , Neumann Martin , Marek Ondřej , Tejkl Adam
Published: March 2020

Soil erosion is a long-term problem that causes the degradation of the earth's surface depending on geomorphological and climatic conditions. Adverse combinations of these conditions can create situations where not only sheet erosion occurs, but also rill processes begin to occur due to the concentration of surface runoff. Erosion processes become undesirable and dangerous when they occur on construction sites. The presented project is basically focused on the effectiveness of protective geotextiles against soil erosion, but processes related to sheer and rill erosion were also investigated. The research was carried out on experimental plots of 4x1 meters, which were placed in the outdoor laboratory in Jirkov. These three plots were set at slopes from 22° to 34° and artificial rain was simulated on them using a rainfall simulator. A second experimental area of ​​the same size was available at the laboratory rainfall simulator at the CTU in Prague, where a modern facility was created for the purpose of soil erosion testing on steep slopes. This device can create slopes up to 40°.

The photogrammetric method „Structure from Motion“ was used for monitoring soil surface before and after each simulation. Orthophotos and digital elevation models were compared with each other to get digital elevation models of difference. Calculation of the ratio between sheet and rill erosion was done by manually creating rill polygons and by calculating the volume changes above the polygons of these rills and over the whole surface. According to preliminary results on these 4 m long slopes, the rill volume represented approximately 30 % compared to the overall volume change.

Shifts of stabilizing natural geotextiles by surface runoff and eroded material were also monitored using photogrammetric methods. Deformations and displacements were measured from differences in the detailed images before and after the simulation. Transversal veins and their shift along the slope were evaluated.

This research is funded by the TA CR  - TH02030428.
Exploring diversity of marine eukaryotes across 385 ka old gravity core using sedaDNA
Authors: Barrenechea Angeles Ines , Beaufort Luc , Ariztegui Daniel , Pawlowski Jan
Published: March 2020

In the last ten years, sedimentary ancient DNA (sedaDNA) becomes a new proxy for paleoceanographic analyses that provide information about large range of non-fossilized taxa. Usually, the sediment samples destinated for sedaDNA study are immediately frozen after collection or stored in special buffer to preserve the DNA. However, there are many cores that have been collected long time before the advent of paleogenomics and that are commonly refrigerated and stored at 4°C. Here, we test whether such cores can be used as a source of ancient DNA, by analysing the sedaDNA samples from 36 meters long marine gravity core that was stored during 14 years at 4 °C. The core MD05-2920 was retrieved during the MD148/PECTEN – Images XII cruise, in Bismarck Sea, off New Papua Guinea, and records the past 385 ka. We analysed samples from 20 layers spanning the interval from 1.6 ka to 384 ka, where isotopic measures of ∂18O showed significant paleoceanographic changes. We started by analysing a universal eukaryotic marker, the V9 (170 bp) region of the 18S rRNA. However, the obtained datasets were dominated by sequences belonging to species of fungi and amoebae that probably originated from post-collection storage. More data were obtained by using markers specific to selected marine taxa, such as foraminifera, radiolaria, and diatoms. The analysis of these data show clearly that the DNA is preserved in marine sediment down to 385 ka old layers. Our study also shows a possibility to exploit the sedaDNA from refrigerated material stored in cores repositories.
Salt diffusion in charged porous media
Authors: Cornelissen Pavan , Leijnse Anton , Joekar-Niasar Vahid , van der Zee Sjoerd
Published: March 2020

Some porous media such as clay have charged surfaces. The presence of these charged surfaces results in a complex system where water flow, salt transport, and the electric field are coupled. This system is important in many fields, such as geotechnical engineering, storage of radioactive waste in clay barriers, enhanced oil recovery, and irrigation with marginal water. The charged surfaces alter the transport properties of ions. For example, clay minerals are often negatively charged due to isomorphous substitution. Cations are therefore attracted to the mineral surface, while anions are repelled, creating a diffuse double layer around the clay particle. Cations are therefore transported preferably over anions through such charged pores. To conserve electroneutrality, a streaming potential develops to counteract diffusion by electromigration. This results in smaller effective diffusion coefficients compared to uncharged porous media. We developed a pore-network model to quantify the effect of the double layer processes on the effective diffusion coefficient. Pore-network models are a suitable tool to include the heterogeneity of pore sizes and surface charge densities seen in nature. In pore-network modeling, the geometry of the pore space is simplified, but the network properties are based on realistic statistics such as pore size distribution and connectivity. The larger scale behavior can be identified by averaging over a large number of pores. The results were strongly dependent on the salinity, as this controls the thickness of the double layers. At high salt concentrations, the diffuse double layer is thin and the differences between charged and uncharged porous media are negligible. However, at low salinity, the double layers are thick and the effective diffusion coefficient of salt was reduced by 25% in charged porous media compared to uncharged porous media, due to salt transport being slowed down to conserve electroneutrality. Hence, the presence of charged mineral surfaces can significantly alter transport rates under low salinity conditions.
Determination of Solar Energetic Particle anisotropies based on four-sector measurements - Study based on STEREO/SEPT in preperation of SolO/EPT
Authors: Bruedern Maximilian , Dresing Nina , Heber Bernd , Berger Lars , Kollhoff Alexander , Kühl Patrick
Published: March 2020

With the launch of Solar Orbiter (SolO) Solar Energetic Particles (SEPs) can be observed at a radial distance of 0.284 to 0.9 AU and an inclination out of the ecliptic up to 34 degree. The properties of SEP observations carry information about their source at the Sun as well as their transport through the interplanetary medium. Their energy is mostly determined close to the Sun. As SEPs propagate outward along the Interplanetary Magnetic Field (IMF) the pitch-angle with respect to the local field is systematically focused due to the radially decreasing IMF. However, stochastic changes are induced by scattering at fluctuations of the IMF. Often the first order anisotropy of SEPs is calculated to disentangle imprints of source and transport. Strong anisotropies indicate periods of weak pitch-angle scattering. Although many modeling and observational studies are based on the anisotropy, its uncertainty is often neglected which could result in inaccurate conclusions. Therefore, we propose a new method based on a bootstrap approach where we consider (1) directional instrument responses, (2) the variation of the magnetic field, and (3) the stochastic nature of detection. Here, we present our procedure and final results for different SEP events using measured data of the IMF and particle fluxes by the Solar Electron and Proton Telescope (SEPT) on board of each STEREO spacecraft. The SEPT provides four viewing directions with a view cone of 0.66 sr each on a three axis stabilized spacecraft. In contrast the Electron and Proton Telescope (EPT) on board SolO also consists of four viewing directions but each telescope has a much smaller view cone of 0.21 sr. Due to the very similar instrument setup we can apply our method both to the SEPT and EPT.
A systematic analysis of the performance of the IPSL-CM5A-LR model for decadal temperature predictions over Europe
Authors: Sgubin Giovanni , Swingedouw Didier , Mignot Juliette , Borchert Leonard , Noël Thomas , Loukos Harilaos
Published: March 2020

Reliable climate predictions over a time-horizon of 1-10 year are crucial for stakeholders and policymakers, as it is the time span for relevant decisions of public and private for infrastructures and other business planning. This promoted, about a decade ago, the development of a new family of climate model: the Decadal Climate Predictions (DCP). Similarly to climate projections, the DCP consists in forced simulations of climate, but initialised from a specific observed climatic state, which potentially represents an added value. Being a relatively new branch of climate modelling the effective application of DCP to impact analysis supporting operational adaptation measures is still conditional on their evaluation.

Here we contribute to this evaluation by exploring the performance of the IPSL-CM5A-LR DCP system in predicting the air temperature over Europe.  Our assessment of the potentiality of the DCP system follows two main steps: (1) the comparison between the simulated large-scale air temperature from hindcasts and the observations from mid-1900 to present day, i.e. NOAA-20CR dataset, which defines a prediction skill, calculated through both the Anomaly Correlation Coefficient (ACC) and the Root Mean Square Error (RMSE); (2) the detection of the “windows of opportunity”, i.e. specific conditions under which the DCP performs better. The exploration of the windows of opportunity stems from a systematic detection that evaluates the DCP skills for each combination of periods, lead times and seasons. Our analysis involves both raw simulations and de-biased simulations, i.e. outputs data that have been adjusted through the quantile-quantile method.

Our results evidence a significant added value over most of Europe with respect to non-initialised historical simulations.  Significant skill scores have been generally found over the Mediterranean sector of Europe and UK, while the performance over the rest of Europe results rather conditional on the season and on the period considered. The best predicted months appear to be those between spring and autumn, while low skills have been found for winter months. Also, the predictions appear to be more performant after the ’80, when a rapid warming signal characterised the temperature over Europe: this shift is well reproduced in the initialised simulations. Finally, skill anomalies between raw and debiased outputs are generally minimal. Nevertheless, debiased data show an overall higher RMSE skill, while ACC skill appears to be slightly higher in winter and slightly lower in summer. These findings may be useful for the exploitation of the IPSL DCP for near-term timescale impact analysis over Europe. Also, our systematic approach for the exploration of the windows of opportunity may be at the base of similar investigations applied to other DCP systems.
Stochastic optimization using MATLAB code for the determination of in situ horizontal stress magnitudes from wellbore logging data
Authors: Song Insun , Chang Chandong
Published: March 2020

We report a MATLAB code for the stochastic optimization of in situ horizontal stress magnitudes from wellbore wall image and sonic logging data in a vertical borehole. In undeformed sedimentary formations, one of the principal stresses is commonly assumed to be vertical, and its magnitude (σv) is simply related to the gravitational overburden. The two horizontal far-field principal stresses (σH and σh) are then theoretically constrained by the relationship between the breakout width (or angular span) and rock compressive strength at a given depth. However, the deterministic relationship yields indeterminate solutions for the two unknown stresses. Instead of using the deterministic relationship between their average values in an interval of borehole, we introduce probabilistic distributions of rock strength and breakout width in the interval. This method optimizes the complete set of in situ principal stresses (σH, σh, and σv) by minimizing the objective function. For the rock failure model, we use a true triaxial failure criterion referred to as the modified Wiebols and Cook criterion that incorporates all three principal stresses. This criterion is expressed in the form of an implicit function with two equation parameters; the uniaxial compressive strength UCS and the internal friction coefficient μ. The Weibull distribution model of UCS in a borehole section (~30 m interval) is obtained from the wellbore sonic logging data using the relation between UCS and P-wave velocity. The value of μ is assumed to be constant at 0.6 based on a previous experimental study. The breakout model is established based on the probabilistic distribution of rock strength at the margins of the breakout for a uniform set of far-field stresses. The inverse problem is solved with a MATLAB algorithm for the optimization by choosing the best-fit set of far-field stresses in a stress polygon. This process also enables one to evaluate the statistical reliability in terms of sensitivity and uncertainty. The stochastic optimization process is demonstrated using borehole images and sonic logging data obtained from the Integrated Ocean Drilling Program (IODP) Hole C0002A, a vertical hole near the seaward margin of the Kumano basin offshore from the Kii Peninsula, southwest Japan.
Palinspastic restorations using interfolding remagnetizations. The case of the Cretaceous widespread remagnetization of the Central High Atlas (Morocco)
Authors: Calvín Pablo , Villalaín Juan J. , Casas-Sainz Antonio M. , Román-Berdiel Teresa , Santolaria Pablo , Mochales Tania , Falcón Irene , Moussaid Bennacer , Oliva-Urcia Belén , Torres-López Sara , Izquierdo Esther , Bógalo María F. , Gil-Imaz Andrés , Ruíz Vicente C. , Sánchez-Moreno Elisa M. , Marcén Marcos , Herrejón Ángela , Jimenez-Sanz Ángela , El Ouardi Hmidou , Pocoví Andrés
Published: March 2020

The Jurassic carbonates of the Central High Atlas (CHA) are affected by a widespread and homogeneous chemical remagnetization. This is an interfolding remagnetization (dated in ca. 100 Ma by comparison with the GAPWP of the African plate) that separates two deformational events; the first one is related to the basinal period in the Atlas (Triassic and Jurassic times) that is responsible of the thick Jurassic sequence that crops out in the CHA. The second one is associated with the tectonic inversion during the Cenozoic caused by the African and European plates convergence, which resulted in the uplift of the cordillera.

Using the Small Circle tools, it is possible (i) to obtain the remagnetization direction and then (ii) use it as reference to obtain the paleodips of each site (i.e. the paleodips at the remagnetization time). This methodology applied to interfolding remagnetizations allows restoring the present-day geometry to the one at ca. 100 Ma and therefore separating the structure associated to the extensional and compressional periods.

This work is framed on an ambitious research project (CGL2016-77560-C2-P, Spanish Ministry of Science and Innovation) in which 700 AMS/paleomagnetic sites and additional 1000 bedding data are integrated to unravel the Mesozoic and subsequent Cenozoic evolution of the CHA. Based on the aforementioned datasets, field work, geophysical (gravimetric and magnetic surveys) constraints and the construction and restoration (at the remagnetization time) of cross-sections, the ultimate goal of the project is to reconstructed and restored the 3-D geometry of the CHA fold-and-thrust belt.  

Here in particular, we present the paleomagnetic data supporting the calculated paleodips. We also analyze how the deformation associated with each of the two deformational events is distributed along the study area. The comparison of dip-domains maps showing the present day attitude and also the pre-inversional one allows analyzing how extensional deformation is more or less associated with particular structures and to understand the importance of the different processes that acted during this period (i.e. deformation associated with extensional faults, salt walls, igneous intrusions, etc.).
SENSECO: Optical synergies for spatiotemporal sensing of scalable ecophysiological traits. (COST Action CA17134)
Authors: Pacheco-Labrador Javier , Aasen Helge , Bialek Agnieszka , Celesti Marco , Cendrero-Mateo Maria Pilar , Hueni Andreas , Kooistra Lammert , Kycko Marlena , Machwitz Miriam , Mihai Laura , Rascher Uwe , Roujean Jean-Louis , Tomelleri Enrico , van der Tol Christiaan , Van Wittenberghe Shari , MacArthur Alasdair , Verrelst Jochem , Schlerf Martin
Published: March 2020

Vegetation in terrestrial ecosystems controls a significant part of the gas and energy exchanges at the atmosphere-biosphere-pedosphere interface. Continuous spatial information about vegetation status (biophysical properties) and photosynthetic rates are needed to understand and model the responses of terrestrial ecosystems to environmental changes induced by human activity. This information is therefore critical to climate change monitoring, adaptation and mitigation. 

Earth Observation (EO) allows the collection spatially continuous Earths surface reflectance at ecologically relevant scales. Recent advances in EO are bringing the chance to retrieve from space a subtle emission from vegetation originated at the core of the photosynthetic machinery of the plants: the chlorophyll sun-induced fluorescence (F). The upcoming Fluorescence Explorer (FLEX) mission from the European Space Agency (ESA) will be the first EO mission dedicated to the exploitation of this signal for the study of vegetation photosynthetic activity. FLEX will fly in tandem with Sentinel-3 (S3). This multi-sensor approach brings new opportunities to test the potential of synergistic use of multi-source data to capture scalable ecophysiological traits. The information provided by FLEX-S3 tandem together with observations from other Copernicus missions will boost the development of novel data analytical techniques, still to be realized. The development of these techniques will requires the combination of EO data with drone-based proximal sensing and tower-based eddy covariance (EC) observations. Together with modeling, this approach will allow solving critical and still open spatiotemporal scaling questions. Recent advances allow nowadays the synergistic use, processing and interpretation of data provided by multiple optical sensors featuring different spatial, spectral and temporal resolutions. The implementation of these techniques requires of the collaboration of the remote sensing, EC, and modeling communities; this need has motivated the development of a network within recently approved COST Action SENSECO. 

SENSECO aims to ensure the multi-scale compatibility of EO measurements and protocols dedicated to the study of ecophysiological properties. This is needed to enable the synergistic use of multi-sensor data, as well as to ensure the transfer and exchange of knowledge on scaling approaches within the European communities. SENSECO achieves his objectives via dedicated expert workshops, training schools and short term scientific missions.
Evaluating the resource recovery potential of fly ash deposits using electrical and electromagnetic methods
Authors: Caterina David , Isunza Manrique Itzel , Michel Hadrien , Bobe Christin , Lucas Hugo , Nguyen Frédéric , Van De Vijver Ellen
Published: March 2020

Burning coal, or municipal solid waste, in thermal power plants and in metallurgical industries is responsible for the production of large amounts of combustion residues, which depending on their particle size and density, are usually referred to as fly or bottom ash. Nowadays, they represent one of the main types of industrial waste generated. Although their composition is strongly dependent on the material burned, they typically contain ferro-aluminosilicate minerals with potentially toxic trace elements and inorganic compounds that can cause environmental problems when stored in non-sanitary landfills. At the same time, they also represent an economically interesting secondary resource as they can be valorised by replacing aggregates/additives in cement or ceramics production. Surprisingly, despite the environmental and economic considerations for these materials, their geophysical properties remain largely unknown. A better understanding of their geophysical identity could enable using geophysical methods to, for example, improve the estimation of the volume and quality of recoverable resources from ash deposition sites. In this contribution, we show the results of geophysical investigations carried out in three of these sites located in Belgium. The main geophysical techniques involved are electrical resistivity tomography, time-domain induced polarization and frequency-domain electromagnetic induction. The deposits studied generally exhibit high electrical conductivity presumably due to the high hygroscopy of fly ash, the high chlorides content and the presence of ferro-aluminosilicate minerals, each of which enhancing electrical conduction mechanisms, although the effect of the first two is conditioned by the level of water saturation present. The presence of magnetite, or other ferri- or ferromagnetic materials, may explain the high magnetic susceptibility observed. Yet, while representing a relatively homogeneous type of waste, strong variations in geophysical properties were observed between and within different sites. This suggests a great influence of the ash production process, but also of the site-specific conditions. These first results argue for further field and laboratory experiments to validate the exploratory geophysical survey results and to identify the decisive influencing factors explaining the observed electrical and magnetic response. Improved insight in the geophysical signature of fly ash deposits will allow for more accurate interpretations of geophysical measurements, in its turn providing a more sound basis for guiding conventional sampling design and thereby contributing to a more reliable assessment of the value of these industrial waste landfills in terms of the secondary resources they can deliver.
Spatial and temporal patterns in seasonal forecast skill based on river flow persistence in Irish catchments
Authors: Quinn Daire , Murphy Conor , Wilby Robert L. , Matthews Tom , Broderick Ciaran , Golian Saeed , Donegan Seán , Harrigan Shaun
Published: March 2020

In this study we assess the seasonal hydrological forecast skill of river flow persistence across a sample of 46 catchments representative of Ireland’s diverse range of hydrogeological conditions. This statistical approach is straightforward to implement as it uses a river’s most recently observed flow anomaly (calculated over a predictor period of a given duration) as its forecasted flow anomaly (for a given horizon). In our hindcast experiment, persistence skill is evaluated against a streamflow climatology benchmark and by assessing the correlations between predicted and observed anomalies. Using the most skilful predictor period of 1-week, we find that the majority of persistence forecasts outperform the benchmark between April and September at the 1-month forecast horizon. However, this narrows to solely the summer months when using 2- and 3-month horizons.  Skill declines with increasing durations of the predictor and/ or forecast horizon period as a catchment is given more time to “forget” initial anomalous streamflow conditions and/or to be impacted by “new” anomalies. High rainfall events, for example, tend to disrupt the persistence of flows and greater forecast skill is thus found in the relatively drier months.

The degree of persistence skill is also strongly conditional on the “memory” inherent to each catchment (i.e. their storage capacity), as indicated by physical catchment descriptors such as the Base Flow Index (correlation ρ with skill = 0.86). Persistence skill is greatest in lowland regions characterised by permeable lithologies, well drained soils and lower annual average rainfall totals. Physical descriptors can thus be used to anticipate the likely performance of river flow persistence as a forecasting tool in rivers outside the catchment sample. Through multiple linear regression analysis, we identified the combination of predictors that produced the best-performing model (adjusted R2= 0.89) and used it to predict the persistence forecast skill level expected in 215 catchments across the country at different horizons and seasons. Highlighting exactly when and where persistence provides higher predictive skill than the reference climatology forecast, we show the value of statistical flow persistence methods as a tougher-to-beat benchmark in the development of more sophisticated seasonal river flow forecasting methods at the catchment-scale. This research also underscores the scope for development of dynamical hydrological forecasting approaches in the wetter, poorly drained catchments underlain by impermeable lithologies, found mainly in the north-western and south-western regions of Ireland.
Environmental managing of bottom ashes from municipal thermovalorization waste for civil applications, as a function of particle size, based on steam washing
Authors: Caviglia Caterina , Destefanis Enrico , Bernasconi Davide , Pastero Linda , Confalonieri Giorgia , Corazzari Ingrid , Turci Francesco , Bonadiman Costanza , Tassinari Renzo , Pavese Alessandro
Published: March 2020

Nowadays, the production of constructional materials requires raw materials obtained through extractive activities that often imply different environmental impacts. In a perspective of a growing sensitivity towards a responsible use of natural resources the attention to materials coming from waste is focused. The waste from the municipal thermovalorization plants can be suitable for this applications, and after moderate and sustainable treatments, can find a role of raw material-second in the construction of works, reducing the need to find additional natural resources and related problems for disposal or storage. The present study aims to explore the possibility of promoting inertization (i.e. reducing the BA’s release in water of environmentally dangerous chemical species below the legal thresholds) of as large a fraction of BA as possible, using ashes from one of the municipal waste incineration plants of Northern Italy, and exploiting byproducts of the incineration cycle, i.e. the spared steam from turbines, which produce electricity, and carbon dioxide from combustion fumes. The treatments discussed are as a function of the particle size (s).  BA are partitioned into three main classes, determined by previous studies s ≥ 4.75, 4.75 > s ≥ 1, s < 1 mm; %. The BA fraction with 4.75 > s ≥ 1 mm was further divided into two portions to optimize the steam washing process: 4.75 > s ≥ 2 mm and  2 > s ≥ 1 mm. BA with s > 4.75 mm are treated with steam washing only. In fact, although they do not contain high concentrations of heavy metals, they largely surpass the Italian legislation thresholds related to the occurrence of chlorides and sulfates. Steam is generally available from modern incineration plants in a considerable amount, and it is more effective than water in removing a variety of impurities/low-crystallinity fragments from the surface of coarse grains. Inertization of BA with 4.75 > s ≥ 1 is investigated by means of both steam washing and accelerated carbonation, to optimize the combination of these methods and expand as much as possible the s-range that requires steam washing only.  As to the BA fraction with s < 1 mm, whose heavy metals content is likely larger than elsewhere, steam washing is of difficult application and therefore we resort to accelerated carbonation.
Investigating the consequences of the desiccation of lakes in the Middle East and Central Asia for regional dust activity
Authors: Banks Jamie , Heinold Bernd , Schepanski Kerstin
Published: March 2020

Over the past several decades, new sources of dust aerosol have appeared in the Middle East and Central Asia due to the desiccation of lakes in the region. It is known that recently dry lakebeds can be efficient dust sources, due to the availability of readily erodible alluvial sediments. Such lake source regions include: Lake Urmia in western Iran; the Sistan Basin in the border area between Afghanistan, Iran, and Pakistan; and most notably, the Aral Sea on the border between Uzbekistan and Kazakhstan. A particularly large area (over 50,000 km2) of the former lakebed of the Aral Sea has become exposed to aeolian wind erosion, leaving Central Asia susceptible to dust storms originating from the young ‘Aral Kum’ (Aral Desert).

In this work we update the dust transport model COSMO-MUSCAT in order to simulate dust emissions from these relatively new dust sources. Making use of the Global Surface Water dataset (produced by the Copernicus Programme) in order to define the surface water coverage, we make estimates of dust emissions under three scenarios: 1) the ‘Past’, representative of water coverage in the 1980s; 2) the ‘Present’, representative of water coverage in the 2010s; and 3) the ‘Dry’ scenario, a worst-case future scenario in which currently drying lake regions are assumed to dry out completely under the pressure of climate change and water overuse. These scenarios are applied to the ‘Dustbelt’ modelling domain, covering North Africa, the Middle East and the Arabian Peninsula, and Central Asia as far east as western China.
Relative humidity fields in the Annecy Alpine valley observed by Ro-Vibrational Raman lidar in the framework of L-WAIVE
Authors: Baron Alexandre , Chazette Patrick , Totems Julien
Published: March 2020

In June 2019, the Lacustrine-Water vApor Isotope inVentory Experiment (L-WAIVE) has been performed in the southern part of the Annecy lake (45°47' N, 6°12' E). The field campaign motivation is to bring a better comprehension on the evaporation processes above Alpine lakes influencing, along with orography, the complex atmospheric structuration. In particular, this two-week field campaign has involved the meteorological Raman lidar WALI (Weather and Aerosol LIdar). An ultra-light aircraft carrying a meteorological probe and a particle sizer performed several vertical profiles above the ground-based Raman lidar with a vertical resolution between 50 and 100 m for flights operated from the ground level (~0.5 km above the mean sea level (AMSL)) and ~4 km AMSL.

This setup is an opportunity to experimentally assess the instrumental errors on both the temperature and the water vapour mixing ratio profiles derived from the ground-based lidar. The methodology used to calculate the error budget will be presented. It will take into account the different types of statistical noises associated with the lidar measurement. In particular, the importance of the spectral filtration in the accuracy of the results will be discussed. The uncertainties associated with the lidar calibration procedure will be quantified. Following this detailed study, the first results of relative humidity will be presented, taking into account the associated error bars.
High-resolution gridded extreme precipitation indices for the wider Greek Region
Authors: Nastos Panagiotis T. , Ntagkounakis George E. , Vassilakis Emmanuel
Published: March 2020

The goal of this study is to create a high-resolution grid of precipitation indices for the wider Greek region using real data from meteorological stations for the 1980-2010 period. Under the risk of increased extreme events caused by climate change, it is important to be able to have a high-resolution gridded extreme precipitation indices in order to overcome the lack of density of observations in both time and space. The development of such a grid can be used to validate model outputs and inform decision makers to better mitigate the damage from extreme precipitation.

The first step of the analysis is to calculate the extreme precipitation indices based on daily observations derived from more than 100 meteorological stations covering a wide range of altitudes and spatial climate patterns existing in Greece. Thereafter, the extreme indices will be multilinearly downscaled to a 12-meter resolution grid. The geophysical parameters used in the downscaling procedure consists of altitude, latitude, longitude, slope, aspect, solar irradiance and Euclidian distance from the water bodies. The altitude information came from the highly accurate 12-meter resolution TanDEM-X Elevation Model, which is a product generated from the TerraSAR-X satellite mission data. The resulting high-resolution patterns will give insight of the spatial and temporal variability of extreme precipitation, over the complex terrain of the wider Greek region.
Multi-model decadal predictions of probabilities for seasonal mean temperature and precipitation extremes
Authors: Kruschke Tim , Befort Daniel , Nikulin Grigory , Koenigk Torben
Published: March 2020

There is great interest from a wide range of stakeholders in near-term climate prediction ranging from seasonal to decadal timescales. While seasonal forecasting is done operationally since more than 20 years now, decadal climate prediction still has to be considered mainly a research subject. The vast majority of existing decadal prediction studies focusses on skill of temporally (typically multi-annual) averaged parameters. This is in line with the general understanding of climate prediction skill to be expectable only for low-frequency climate variability on larger spatial scales. However, while such predictions of multi-annual means might be skilful, they contain little information on shorter timescale extremes.

We present a different approach, that is the temporal pooling of seasonal means to form probabilistic forecasts. Thus, rather than for example analyzing the anomaly of the summer temperature averaged over a decade, we examine the probabilities of extreme seasonal summer temperatures within this decade (exceedance of some quantile of the climatological summer temperature probability distribution). This approach complements the common multi-annual means and hence extends the usability of decadal predictions.

For this study we use decadal climate predictions produced by the CMIP5 multi-model ensemble as well as available CMIP6-DCPP contributions. We analyze these large ensembles’ skill regarding forecasting the probability of extremely warm and extremely dry seasons. A season is considered to be “extreme” if the seasonal mean temperature (precipitation) is above (below) the 5th (1st) sextile of the climatological probability distribution.

We will show that the forecast skill in this respect is comparable to that obtained for the common approach, based on multi-annual year averages. This means the existence of significant skill for many regions globally when considering the probability of extremely warm temperatures. Skill regarding predicting extremely dry seasons (i.e. low precipitation) is rather limited, though.

These results generally agree with studies applying the common multi-annual averaging approach for assessing skill of temperature and precipitation climate predictions but extend the existing knowledge by covering probabilities of seasonal mean extremes. Hence, this approach states an important contribution towards the extended utility of decadal climate predictions. An additional benefit of the framework proposed here is the larger sample size when pooling instead of averaging. This allows to consider extreme events of higher magnitude before reaching the limitations of statistical uncertainty hampering the derivation of robust results.
Holocene Paleoenvironments in the Western Mediterranean Sea: palynological evidences on the Algerian coast and climatic reconstructions
Authors: Coussin Vincent , Penaud Aurelie , Combourieu-Nebout Nathalie , Peyron Odile , Miras Yannick , Sicre Marie-Alexandrine , Babonneau Nathalie , Cattaneo Antonio
Published: March 2020

Past and present oceanographic and climatic conditions along the Algerian coast involve complex mechanisms. Atlantic Ocean surface waters enter the Mediterranean Sea by the Gibraltar strait and become the Algerian current flowing along the North African coast forming a succession of eddies. Deep-water upwelling plumes is another recurrent feature of the ocean circulation along the Algerian margin. Past vegetation changes and the role of paleohydrological changes have been poorly described in this region. This work combines palynological (pollen and dinoflagellate cysts) and biomarker data to assess changing environmental and climatic conditions over the past 14 ka BP (late glacial and Holocene) acquired from the marine core MD04-2801 (Algerian coast, 2067 m water depth, Prisma cruise).

A total of 79 samples have been analyzed over the last 14 000 years BP. Palynological and organic biomarker proxy data were used to investigate the links between past sea surface temperature (SSTs) and hydrological changes on the observed regional environmental changes documented at centennial timescale resolution. Our data indicate (i) recurrent upwelling cells during relatively dry climatic conditions of the Younger Dryas (12.7 to 11.7 ka BP), the Early Holocene (11.7 to 8.2 ka BP) and from 6 ka BP onwards, (ii) an increase of fluvial discharges between 8.2 and 6 ka BP during the African Humid Period, and the concomitant colonization of coastlands by the Mediterranean forest. The comparison between our results and other western Mediterranean palynological records underlines the singularity of our results along the Algerian margin in terms of dinocyst assemblages and notably the over-representation of heterotrophic taxa. Palynological data shows direct links between continental dryness and marine hydrological conditions. Finally, we applied the Modern Analogue Technique to our pollen assemblages along the core in order to reconstruct seasonal and annual precipitations and temperatures and compare our local climatic patterns to regional climate signals at basin scale for the Holocene period.
Are detailed urban canopy parameters necessary for modelling the urban climate in Africa?
Authors: Brousse Oscar , Van de Walle Jonas , Arnalsteen Lien , Demuzere Matthias , Thiery Wim , Wouters Hendrik , van Lipzig Nicole P.M.
Published: March 2020

Local Climate Zones (LCZ) have now been widely accepted and used by the urban climate community (Ching et al., 2018). However, their use over Sub-Saharan Africa has still been limited because of data scarcity in the region. Brousse et al. (2019, 2020) demonstrated the added value of applying spatially variant urban canyon parameters derived from LCZ in the urban climate model TERRA_URB – embedded in the COSMO-CLM model. Despite its promising results, thermal and morphological parameters extracted out of the ranges proposed by Stewart and Oke (2012) are mostly derived from Western cities. Hence, uncertainties related to the use of unascertained urban forms and functions of African cities for urban climate modelling have not yet been evaluated.

To quantify the sensitivity of the model to more representative urban canopy parameters of African cities, this study sets up a methodology for: (i) obtaining from in situ measurements archetypal parameters of LCZ classes for Kampala (Uganda); and (ii) simulating the potential effect of the newly defined urban structure on the local climate.

In situ data were obtained during field work held in the summer months of 2018. A representative sample of 1300 measurement points was selected throughout the city of Kampala, for which both quantitative (road width, distance between houses, heights of buildings) and qualitatively estimated (vegetation fraction, road-wall-roof material) variables were collected.  These variables enabled the development of an updated LCZ map of the city of Kampala.

To evaluate the model’s sensitivity to the new spatially explicit urban morphological and thermal parameters, this new information was fed into the TERRA_URB scheme at a horizontal resolution of 1 km for a 3-months period (December 2017 – February 2018). The run was nested within a 12 km simulation forced by ERA-Interim reanalysis data. Results show tangible effects of the updated parameters on the 2-meter air temperature, land surface temperature and surface energy balance components. Still, no major improvements in model skill compared to the default LCZ framework proposed by Brousse et al. (2020) were found. [1] [WT2] This study is among the first studies to test the sensitivity of an urban climate model to more realistic urban parameters in Africa and aims at triggering more research to be done in the area with a variety of urban climate models.