bluuebunny/crossref_metadata_2025 huggingface dataset:
The DEnse mulTi-paramEtriC observations and 4D high resoluTion imaging (DETECT) experiment, a new paradigm for near-fault observations
Authors: Picozzi Matteo , Iaccarino Antonio Giovanni , Bindi Dino , Cotton Fabrice , Festa Gaetano , Strollo Angelo , Zollo Aldo , Stabile Tony Alfredo , Adinolfi Guido Maria , Martino Claudio , Amoroso Ortensia , De Matteis Raffaella , Convertito Vincenzo , Spallarossa Daniele ,   DETECT team
Published: March 2022

Near-fault observations can provide insights into the physical process interaction between fault slip activation, fluid presence/migration and seismicity production, processes acting at different timescales that generate large earthquakes.

The DETECT experiment aims at exploiting very dense seismic networks deployed across a segmented faults system to foster the development of scientific integrated methodologies for monitoring and imaging the faults behavior during the inter-seismic phase. Target of the monitoring is to: detect and track space-time trends of different source parameters that could be related to a preparation process leading to a larger earthquake; investigate the frictional and stress states of the fault segments to anticipate the characteristics of the future large earthquake (e.g., hypocenter but also future large seismic energy release locations); analyze the interactions between the different fault segments to model/anticipate potential cascade effects.

The DETECT experiment is carried out in the Irpinia area (southern Italy), one of the regions in Italy and Europe showing the highest seismic hazard. Since august 2021, a constellation of 20 seismic arrays, for a total of 200 seismic stations (20 broad-band sensors and 180 short-periods), has been installed over the fault segments responsible for the Ms 6.9, 1980 Irpinia earthquake, the strongest and most destructive seismic event of the last half-century in southern Italy.

DETECT results from a joint effort of local Universities, National and International Research Institutes. A novel and crucial aspect is that, differently from most studies concerning intra-plate earthquakes which are usually carried out after that large magnitude earthquakes have occurred, DETECT aims to put us in advantageous position and to unveil the preparatory process that generate large earthquakes and anticipate the role of the segmentation by studying at one time different fault segments, some of which are in rather late stage of their seismic cycle.

With this contribution, we aim to present the DETECT experiment, the preliminary results and foster additional cooperation including complementary expertise to further enrich the partnership.
A magnetosheath hydrodynamic plasma flow model around Mercury
Authors: Schmid Daniel , Narita Yasuhito , Plaschke Ferdinand , Volwerk Martin , Nakamura Rumi , Baumjohann Wolfgang
Published: March 2022

The magnetosheath is defined as the plasma region between the bow shock, where the super-magnetosonic solar wind plasma is decelerated and heated, and the outer boundary of the intrinsic planetary magnetic field, the so-called magnetopause. Recently we  presented an analytical magnetosheath plasma flow model around Mercury, which can be used to estimate the plasma flow magnitude and direction at any given point in the magnetosheath exclusively on the basis of the plasma parameters of the upstream solar wind. However, this model assumes a constant plasma density and velocity along the flowlines. Here we present a more sophisticated model were we take hydrodynamic effects into account, to also obtain the density and velocity change along the flowline. The model serves as a useful tool to trace the magnetosheath plasma along the streamline both in a forward sense (away from the shock) and a backward sense (toward the shock), offering the opportunity of studying the growth or damping rate of a particular wave mode or evolution of turbulence energy spectra along the streamline in view of upcoming arrival of BepiColombo at Mercury.
Modelling marine organic aerosol and its impact on clouds in the Arctic 
Authors: Leon Anisbel , Heinold Bernd , van Pinxteren Manuela
Published: March 2022

Marine organic aerosol is a major contributor to cloud condensation nuclei and ice nucleating particles over pristine open-ocean and coastal regions and thus has an important impact on radiation, precipitation, and atmospheric dynamics. In the Arctic, the summer-time loss of sea ice together with the rapid ice retreat are key factors for potentially increased marine aerosol emissions. In our planned studies with the aerosol-climate model ICON-HAM, we want to investigate the influence of primary marine organic aerosol on the Arctic climate and its rapid warming. Currently, the model development focuses on the implementation of a detailed, species-resolved ocean emission scheme. Here, we present the first results of an offline version following Burrows et al. (2014). The new emission scheme has been applied in ICON-HAM. This allows for including the marine organic aerosol’s life cycle and interactions with mixed–phase Arctic clouds, focusing on potential ice-active species.
Effect of root hairs and benzoxazinoids on maize microbiome and its enzymatic activity in the rhizosphere
Authors: Bilyera Nataliya , Waelchli Jan , Shi Lingling , Caggia Veronica , Zhang Xuechen , Shlaeppi Klaus , Dippold Michaela A. , Razavi Bahar S. , Spielvogel Sandra
Published: March 2022

Root morphology and the composition of root exudates shape the spatial organization and various processes in the rhizosphere. For instance, root hairs are essential for plant nutrition, while secondary plant metabolites (i.e. benzoxazinoids) ensure plant defence from herbivore and fungal infection. Nevertheless, it is still unknown to which extent root hairs and benzoxazinoids may change the microbiome and enzymatic activities, as well as formation of rhizosphere hot- and coldspots.

To study the effect of root hairs and benzoxasinoids on the rhizosphere microbiome structure and its enzymatic activities we compared mutants with defective root hairs rth3 or with reduced benzoxazinoids bx1 with the corresponding wild-type (WT) maize.

Root hairs increased acid phosphatase activity by 80 % promoting mineralization of organic phosphorus sources to available forms in the hotspots. In the coldspots, broken root hairs in WT facilitated the intensive microbial hotspots with up to two times higher β-glucosidase and chitinase activities, compared to rth3.

The presence of benzoxazinoids in root exudates strongly supported plant defence against pathogenic fungi (i.e., genus Fusarium and Gibberella) while the total microbial biomass remained unaffected. In response to the presence of pathogenic fungi, bx1 exuded 70 % more chitinase for defence purpose to partly compensate for benzoxazinoids deficiency, which was however, less efficient against pathogens than the presence of benzoxazinoids.

Overall, we conclude that: i) root hairs facilitate better plant nutrition at the shortage of available nutrients (i.e., coldspots), while; ii) the presence of benzoxazinoids in exudates protect plant from pathogenic microorganisms. This two root traits are promising for plant breeding of genotypes suitable for sustainable agriculture and organic farming.
Storm-type specific scaling of sub-daily precipitation with temperature over the North Atlantic and Europe
Authors: Catto Jennifer , Sansom Phil , Stephenson David
Published: March 2022

Sub-daily precipitation extremes are expected to increase in intensity in a warming climate, at a rate higher than that expected from the Clausius Clapeyron scaling. Depending on the region, these precipitation extremes can be caused by different weather system types, such as extratropical or tropical cyclones, fronts, and thunderstorms. In this study we use a storm typology, based on the objective identification of cyclone, fronts and thunderstorms, to add insight to the scaling relationship between temperature and extreme precipitation.

We use 6-hourly information on the type of weather system present at each grid box over the North Atlantic and European region from ERA5 (1981-2000) during boreal winter (DJF). The mean hourly 2-m dew-point temperature over the 6 hours closest to the weather system type, and the maximum of the hourly precipitation over the same period are then used to estimate the scaling of the precipitation extremes with temperature for each storm type. Preliminary results using quantile regression we find significantly larger scaling for weather systems including thunderstorms (greater than CC scaling) than for those that do not. We also find that for the most common weather systems over Northern Europe (front only and cyclone and front together), the scaling of extreme precipitation with temperature is below CC scaling. The future impacts of the extreme precipitation events will depend on the future changes in the frequency of different weather system types as well as the temperature scaling.
Martian crustal magnetic fields and their control of ionospheric plasma densities and temperatures
Authors: Andrews David , Andersson Laila , Ergun Robert , Eriksson Anders , Pilinski Marcin , Stergiopoulou Katerina
Published: March 2022

Mars Express and MAVEN observations have demonstrated the influence of Mars’s spatially variable crustal magnetic fields upon the configuration of the plasma in the ionosphere. This influence furthermore leads to variations in ionospheric escape, conceivably in part through the modification of the plasma density and electron temperature in the upper ionosphere. However, quantifying this control remains challenging given the generally dynamic and spatially varied nature of the Mars solar wind interaction, and the therefore naturally varying densities and temperatures of the upper ionosphere in particular. In this study we examine MAVEN Langmuir Probe and Waves data, finding a very clear correspondence between the structure of the crustal fields and both the measured electron temperatures and densities, by first constructing a robust “average” profile from which departures can be quantified. Electron temperatures are shown to be systematically lower in regions of strong crustal fields over a wide altitude range, as has been previously reported. Here, we additionally use measurements made by MAVEN in the solar wind, to explore the dependence of this crustal field control on the coupling to the solar wind and IMF.  We also attempt to quantitatively determine the altitude range over which this coupling between plasma density and temperature and crustal fields is effective.
Vp/Vs Temporal Variation as Precursor Anomalies for the 2018 Palu Earthquake
Authors: Prayogo Angga Setiyo , Prasetyo Retno Agung , Perdana Yusuf Hadi , Martha Agustya Adi , Yuliatmoko Rahmat Setyo , Rohadi Supriyanto , Riama Nelly Florida , Triyono Rahmat
Published: March 2022

The Palu earthquake on September 28, 2018 with a magnitude of Mw 7.5 was one of the most destructive earthquakes in Indonesia. This earthquake also caused an underwater avalanche and caused a tsunami along the coast of the Palu bay. The source of the earthquake was the tectonic activity of the Palukoro fault. Until now, several research methods on earthquake precursors around the world have tried to find out whether there are long-term and short-term natural clues before the occurrence of a large and destructive earthquake. In this study, we examined the precursor anomaly of the earthquake in the Palukoro fault area using the least squares calculation method to obtain Vp/Vs by referring to the Wadati diagram. We used detailed earthquake catalog data from the nearest BMKG Station from the source, namely data on the arrival time of P and S waves from all earthquake events in the Palukoro Fault area from 2017 to 2017. 2020. The results show an anomaly pattern on the monthly Vp/Vs chart. The decrease in the value of Vp/Vs by an average of 6% occurred within a span of 9 months before the main Palu earthquake. Vp/Vs variations are an indication of the presence of tectonic stress and strain forces before an earthquake so that it can be used as an indication of earthquake precursors.
Low level observations of the atmospheric light phenomena in Hessdalen, Norway
Authors: Hauge Bjørn Gitle , Kjøniksen Anna-Lena
Published: March 2022

Unidentified Atmospheric light phenomena have been observed in the Hessdalen valley for decades. The valley is remote and sparsely populated, located in the sub-arctic region. This region is famous for its copper, zinc, and iron ore.  Mining has been going on since 1644 and the landscape is scattered with mine entrances and miles of tunnels deep down in the ground. Some places are heavy polluted by sulphur. Mountain areas with Gabbro and Granite rock leaks Radon gas to the air and water. Recent interests around the geological features of the valley have revealed interesting geological features. Here we present new low-level observations by spectral cameras, which suggest that the lights may emanate up from the ground.
Monitoring climate related risk and opportunities for wine sector: the MED-GOLD Pilot Service 
Authors: Dell'Aquila Alessandro , Graça António , Teixeira Marta , Fontes Natacha , Gonzalez-Reviriego Nube , Marcos-Matamoros Raul , Chou Chihchung , Terrado Marta , Giannakopoulos Christos , Varotsos Konstantinos , Caboni Federico , Locci Riccardo , Nanu Martina , Porru Sara , Argiolas Giulia , Bruno Soares Marta , Sanderson Michael
Published: March 2022

MED-GOLD is a four-year research and innovation project, whose main aim was to co-develop climate services for three staples of the Mediterranean food system, namely grapes, olives and durum wheat. This paper describes the methodology adopted for the co-development of the pilot climate service for the wine sector, focusing on the Douro Demarcated Region (DDR) in northern Portugal. 

In the first step, the MED-GOLD Champion Sogrape Vinhos identified  the key management decisions, the climatic information of interest and users’ needs for the wine sector in the DDR. From this information, the relevant bioclimatic indicators (and the key essential climate variables - ECVs) were identified and obtained. Afterwards, two compound risk indices, the Sanitary and Heat Risk indices, were also calculated as a combination of some of the aforementioned bioclimatic indicators. This methodological work was validated against the empirical climate characterization for the region of interest, of several ‘bad’ and ‘good’ years  chosen by users according to their recollections of grape and wine production outcomes, namely overall quality and yields. In addition, the overall strategy for selection of these years is presented. Then, the two components of the service based on seasonal predictions and longer-term climate projections are described. 

The final step was the development of the MED-GOLD Dashboard, an interactive tool that displays detailed historical climate data, seasonal predictions and climate projections. The dashboard is a map-based, user-focused visualization interface to aid easy access to and understanding of the data computed in an ICT platform. The dashboard was iteratively co-designed with the users to ensure their needs were met.
An integrated approach for engineering - geological modelling in view of seismic microzonation
Authors: Varone Chiara , Baris Anna , Caciolli Maria Chiara , Fabozzi Stefania , Fortunato Carolina , Gaudiosi Iolanda , Giallini Silvia , Mancini Marco , Martelli Luca , Modoni Giuseppe , Moscatelli Massimiliano , Paolella Luca , Simionato Maurizio , Sirianni Pietro , Spacagna Rose Line , Stigliano Francesco , Tentori Daniel , Razzano Roberto
Published: March 2022

Terre del Reno is a municipality in the Emilia-Romagna Region (Italy) that experienced relevant liquefaction events during the 2012 seismic crisis, which was characterised by two main shocks (ML 5.9 and 5.8).  Such events are mainly related to the complex geo-stratigraphic setting of the area. In this background, the present work is devoted to achieving two main objectives: i) define a new integrated methodology to assess liquefaction susceptibility in complex stratigraphic conditions through a multi-level approach; ii) perform a level 3 seismic microzonation study of Terre del Reno. To this purpose, more than one thousand geophysical and geotechnical measurements available from three different databases and some hundreds of new collected investigations were stored in a dedicated geodatabase. Data and metadata, that were spatially and statistically manipulated to guarantee their harmonization, standardization, and uniqueness, were explored to reconstruct a model for the Terre del Reno subsoil. Specifically, a geological model of the studied area (~ several hundreds of meters) was first reconstructed as well as the seismic bedrock geometry (the latter defines as the layer characterized by the stiffness requirement: Vs > 800 m/s). This model was obtained by integrating deep bore-hole data available from previous studies and geophysical and geotechnical investigations. Furthermore, a high-resolution geological reconstruction of the upper 30 m has also been performed through sedimentological and paleo morphological analysis to characterize the sedimentary units affected by liquefaction. This analysis may be used to compare both well-known and innovative geotechnical indicators for liquefaction susceptibility assessment. Thus, a set of acceleration time histories, that are spectrum-compatibles with the spectrum of reference input motion at outcropping bedrock of the site, were used as input in 1D and 2D site effect numerical modelling. The obtained results were synthetized and represented in a level 3 seismic microzonation study with the aim of providing operational indicators devoted to urban planning and for challenging problem related to liquefaction.
A Template To Obtain Information On Gravitational Mass Movements From The Spectrograms Of The Seismic Signals Generated
Authors: Suriñach Emma , Flores Márquez E. Leticia
Published: March 2022

We present a method to obtain a parameter (b) that allows to analytically reproduce the shape of the increase in amplitude at high frequencies in time of the SON (Signal Onset) section of the spectrogram of seismic signals generated by gravitational mass movements (snow avalanches, lahars and debris flows) descending a slope and approaching a seismic sensor. This increasing shape is a consequence of the appearance of energy at high frequencies as the gravitational mass approaches the seismic sensor. The developed method to obtain the parameter (b) allows to analytically reproduce the increasing shape of the SON section. Since this shape is related to the speed of the avalanche and the characteristics of the terrain, the parameter allows us to "classify" the mass movement with only one sensor. This methodology includes a link between the propagation properties of seismic waves and the results of the application of an image processing using the Hough transform.

Depending on the type of event, differences are obtained in the order of magnitude of the values of b. The mean value of b for lahars is around 0.003 s-1, that for debris flows is an order of magnitude greater (0.017 s-1) and an order of magnitude less than that for avalanches (0.12 s-1). Furthermore, differences in b are observed within each type of event. This fact allows us to create a template with different values of parameter b to help in the classification within each type of mass movement by only superimpose graphically the corresponding spectrogram with the appropriate template when they are at the same scale.

Once the value of b has been determined, the characteristics of the mass movement should be set according to the judgment of experts. This must be done for each site and for each type of gravitational mass movement. The application to one lahar and one debris flow is presented as an example.
Regional groundwater funneling within the hyporheic zone
Authors: Mojarrad Brian Babak , Wörman Anders , Riml Joakim
Published: March 2022

Groundwater-surface water interaction controls the exchange of contaminants, solutes and energy between aquifers and surface water resources. In particular, groundwater contamination and solute transport time is prolonged due to the impact induced by hyporheic fluxes within the streambed sediment. The retention of contaminants and solutes in streambed sediment influence the ecology and biodiversity of hyporheic zone. In this research, a numerical groundwater model was developed and supported with hydrologic and hydrogeological observations of the Krycklan catchment, Sweden, to investigate the impacts of hyporheic flows on the regional groundwater flow direction and discharge areas at the groundwater-surface water interface along stream networks. The applied method involved a multiscale modelling framework where the regional groundwater and hyporheic flows were analyzed via numerical modelling and exact solutions, respectively; and then superimposed to obtain the subsurface flow field. The regional groundwater flow was analyzed in presence and absence of the hyporheic flow and significant changes in groundwater flow trajectories and size of discharge areas were found upon adding the hyporheic flow fields. In particular, the upward groundwater flow was strongly contracted near the streambed surface due to the impact of hyporheic flow, which led to groundwater funneling and an acceleration of groundwater discharge velocities into streams. Consequently, the size of groundwater coherent discharge areas were substantially reduced leading to significantly fragmentation of groundwater discharge zones due to the impact of hyporheic fluxes.
A gap filled procedure for the analysis of frost days in southern Italy
Authors: Guagliardi Ilaria , Caloiero Tommaso , Pappagallo Giuseppe , Barca Emanuele
Published: March 2022

The studies on the climate changes effects aim at prevent their often-harmful consequences for people and ecosystems. Therefore for this important impact, the quantity and the structure of data involved in those studies have to follow precise and well defined standards. Since long time, many countries are endowed with networks of climatic gauges to track the dynamics of climatic variables in space and time. Unfortunately, the efficiency maintenance of those networks requires a constant control of the tools that collect data to avoid measuring errors and missing data which negatively impacts on studies based on robust statistical methodologies. In order to overcome the problem of missing data, in recent times powerful statistical procedures were born. These approaches contain novel and effective methodologies that, under suitable boundary conditions, are capable to reconstruct with good reliability the set of missing data. Within this context, the aim of this study is to perform a reliable trend analysis of the minimum temperature by means of a gap-filled database of 8 temperature series collected in the Calabria region, in Southern Italy. Specifically, considering the past studies, which evidenced that winter conditions are changing more rapidly than any other season, in this study particular attention has been paid to the temporal changes of the frost days, i.e. the annual count of daily minimum temperature < 0 °C. In fact, decline in frost days could have lasting impacts on ecosystems, especially in mountainous and forested area such as the Calabria region, in which about 42% of the regional area is located over 500 m a.s.l.. Indeed, the number of frost days recorded during the winter is particularly important for the health of mountain forests (for example by killing parasites and harmful insects, or mitigating summer water stress) and for the conservation of the snowpack, which insulates the soil, providing subnivean shelter to animals and prevents freezing of roots and microorganisms. With this aim, in the present work, a statistic-probabilistic methodology has been presented and applied to select the most effective data reconstruction method among those known from current literature. After the missing data reconstruction, the Mann-Kendall non-parametric test has been applied evidencing a declining trend of frost day’s number for six out of eight series, thus confirming an overall rise of the minimum temperature in the study area
Land-Ocean Transitions in the Tropics: What Makes MCSs Persist?
Authors: Kruse Irene Livia , Haerter Jan O.
Published: March 2022

Mesoscale convective systems (MCSs), long-lived convective clusters spanning more than 100 km horizontally, are known to be the dominant source of rainfall in the tropics, and the longest-lived MCSs are shown to be largely responsible for tropical extreme precipitation [Roca and Fiolleau, 2020]. Globally, the most extreme storms tend to be located over land, and the most intense storms over oceans tend to be adjacent to land, where motion is favored from land to ocean, e.g. tropical West Africa and the adjacent Eastern Atlantic Ocean [Zipser et al., 2006]. These systems are organized and maintained by the atmospheric characteristics needed for deep convection (moisture, instability, and lift), and the presence of vertical wind shear [Schumacher and Rasmussen, 2020]. Dry soils seem to have a large influence on strengthening organized convection [Klein and Taylor, 2020]. However, the mechanisms behind the intensification or dissipation of MCSs advected from land to sea are not well established yet.
To address this shortcoming, we investigate the evolution of MCSs emerging from satellite data over tropical Africa and the Eastern Atlantic Ocean. We use a database of tracked MCSs from infrared satellite data, TOOCAN [Fioellau and Roca, 2013]. Using these data we built a lagrangian tracker by which groups of MCSs - occurring in spatial proximity of each other with a 15 deg x 15 deg patch - are followed. We study the evolution of the cloud field within the patch, initiated at the time and latitude of maximum convective activity in the season. We superimpose a collocated satellite precipitation dataset, IMERG, to gain insight into the precipitation field related to the tracked MCSs, and study the environmental properties (temperature, wind profiles) using ERA5 reanalysis datasets. Over land, we find (i) that the MCS cover exhibits a clear diurnal cycle with peaks in the late afternoon and (ii) the lagrangian patch moves with a near constant velocity. Over ocean, we find a (i) decrease of the MCS cover which does not correspond to a decrease in precipitation and that (ii) at times the MCS evolution becomes stationary, corresponding to near-zero wind profiles. By generalizing these results to five years of tracked MCSs, we aim to gain insight into what environmental conditions are necessary for the development of strongly organized MCS fields over the coastal regions and the ocean, which, if persistent in time, could eventually evolve into tropical cyclones.
When do regional tropical climate signals become detectable in CMIP5/6 simulations?
Authors: Suresh Gopika , Suresh Iyyappan , Lengaigne Matthieu , Vialard Jérôme , Izumo Takeshi , Kwatra Sadhvi
Published: March 2022

Estimating when anthropogenically-forced signals emerge from ambient natural climate variability is crucial for climate-change detection. Here we propose a new method for estimating the emergence time of climate signals based on a significance test on the nonlinear trend rather than the commonly-used method based on a signal-to-noise ratio. This method is less sensitive to the choice of a confidence level (0.1, 0.05 or 0.01) than the previous method to commonly-used signal to noise ratios (0.5, 1 or 2). For signals that tend to emerge in the late 21st century, our method tends to yield earlier detection dates, by taking the large number of degrees of freedom into account. Here, we apply this method to relative SST (RSST, SST minus its tropical mean) changes, which tend to emerge much later than SST change signals. RSST is an indicator of changes in the atmosphere vertical stability and thus of changes in tropical cyclones intensity and precipitation. By 2100, CMIP5/6 projections indicate greater than tropical average warming (positive RSST signal) in the central and eastern equatorial Pacific, equatorial Atlantic, and Arabian Sea, and reduced warming (negative RSST signal) in the three southern hemisphere subtropical gyres. In general agreement with observations, relative warming in the Arabian Sea and relative cooling in the South-Eastern Pacific are already detectable in a majority of models (median emergence time < 2020), making these regions suitable for testing a model's ability to predict a regional SST trend. In contrast, RSST signals in other regions do not become detectable until after 2050. Tropical precipitation projections indicate more (less) rainfall in regions of positive (negative) RSST change that typically emerge one or two decades later than RSST signals. This lack of currently-detectable regional rainfall trends in CMIP models makes it difficult to evaluate their ability to predict tropical regional rainfall trends. In general, signals tend to emerge later in CMIP6 than in CMIP5 due to both weaker signals and larger climate noise. The only exception is Sahel, where CMIP6 models already display a detectable rainfall increase, that is not yet detectable in CMIP5.
An Evaluation of Algebraic Turbulence Length Scale Formulations using Budget-Based Diagnostics
Authors: Reilly Stephanie , Bastak Duran Ivan , Theethai-Jacob Anurose , Schmidli Juerg
Published: March 2022

The most frequently used turbulence parameterizations in numerical weather prediction (NWP) and general circulation (GC) models are turbulence schemes with a prognostic turbulence kinetic energy (TKE). These turbulence schemes are strongly dependent on an ad-hoc quantity, the turbulence length scale. The turbulence length scale is used to parameterize the molecular dissipation of TKE and is also required for calculating the turbulence exchange coefficients. Traditionally, the turbulence length scale formulations do not take into account the transfer of TKE across scales, as they are designed for scales above the energy production range of the turbulence spectra. However, with computational power growing, it has become increasingly possible to simulate at scales within the energy production range, that is within the gray zone of turbulence. At resolutions within the gray zone, the cross-scale transfer of TKE needs to be taken into account in order to accurately represent the turbulence. For this purpose, a turbulence length scale diagnostic was developed that can be used for resolutions in the gray zone. This is achieved by calculating the turbulence length scale from the so-called effective dissipation rate, a combination of the cross-scale TKE transfer and the dissipation rate. The effective dissipation rate is estimated from the budget of the TKE using large-eddy simulation (LES) data. A similar approach can be used to calculate turbulence length scale from the budgets of scalar variances. This study makes use of three different turbulence length scale diagnostics based on: the TKE, the variance of the total specific water content, and the variance of the liquid water potential temperature. Four algebraic turbulence length scale formulations are evaluated using the turbulence length scale diagnostics as a reference. The evaluation of the algebraic turbulence length scale formulations is conducted for several idealized LES cases, simulated using the MicroHH model. These LES cases represent a variety of different atmospheric boundary layer conditions.
Seasonal prediction of North American wintertime cold extremes in GFDL SPEAR forecast system
Authors: Jia Liwei , Delworth Thomas , Yang Xiaosong , Cooke William , Johnson Nathaniel , Wittenberg Andrew
Published: March 2022

Skillful prediction of wintertime cold extremes on seasonal time scales is beneficial for multiple sectors. This study demonstrates that North American cold extremes, measured by the frequency of cold days in winter, are predictable several months in advance in Geophysical Fluid Dynamics Laboratory’s SPEAR seasonal (Seamless system for Prediction and EArth system Research) forecast system. Two predictable components of cold extremes over North American land areas are found to be skillfully predicted on seasonal scales. One is a trend component, which shows a continent-wide decrease in the frequency of cold extremes and is attributable to external radiative forcing. This trend component is predictable at least 9 months ahead. The other predictable component displays a dipole structure over North America, with negative signs in the northwest and positive signs in the southeast. This dipole component is predictable with significant correlation skill for 2 months and is a response to the central Pacific El Nino as revealed from SPEAR AMIP-like simulations. 
Interrelation between the Indian and East Asian Summer Monsoon: A complex network-based approach
Authors: Gupta Shraddha , Su Zhen , Boers Niklas , Kurths Jürgen , Marwan Norbert , Pappenberger Florian
Published: March 2022

The Indian Summer Monsoon (ISM) and the East Asian Summer monsoon (EASM) are two integral components of the Asian Summer Monsoon system, largely influencing the agro-based economy of the densely populated southern and eastern parts of Asia. In our study, we use a complex network based approach to investigate the spatial coherence of extreme precipitation in the Asian Summer Monsoon region and gain a deep insight into the complex nature of the interaction between the ISM and the EASM. We identify two dominant modes of ISM-EASM interaction – (a) a southern mode connecting onset of the ISM over the Arabian Sea and southern India in June to the onset of Meiyu over south-eastern China, i.e., lower and middle reaches of the Yangtze river valley, and (b) a northern mode relating the occurrence and intensity of rainfall over the northern and central parts of India to that in northern China during July. Through determination of specific times of high synchronization of extreme precipitation, we distinctly identify the particular large-scale atmospheric circulation and moisture transport patterns associated with each mode. Thereafter, we investigate the role of the different components of the tropical intraseasonal oscillations, such as the Madden-Julian Oscillation and the boreal summer intraseasonal oscillation, in the intraseasonal variability of the relationship between the ISM and the EASM.

This work is funded by the CAFE project which has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 813844.
Investigation on the impact of environmental parameters on ship-based observations of trade wind shallow cumuli and precipitation.
Authors: Acquistapace Claudia , Lange Diego , Risse Nils , Späth Florian
Published: March 2022

During the EUREC4A campaign, a synergy of ship-based remote sensing instruments deployed onboard the research vessel (RV) Maria S. Merian collected high-resolution observations of clouds, precipitation, and atmospheric boundary layer (ABL). Various data papers describe in detail the datasets collected. This work uses data from the W-band cloud radar, the Micro Rain Radar (MRR-PRO), the Atmospheric Raman Temperature and Humidity Sounder (ARTHUS), the wind lidar, and the radiosoundings. 

We statistically characterize clouds and precipitation properties by looking at specific observables collected during the campaign. We derive the W-band radar moments statistics (CFADs), the rain rate, and virga radar reflectivity profiles. We also display the relation between the W-band radar reflectivity and the radar skewness, revealing insights into the precipitation onset.

We investigate how the statistical distributions obtained for each of the observables mentioned above vary as a function of some environmental parameters like the columnar humidity, the turbulence, quantified in terms of eddy dissipation rate, and the vertical air motion.

The analysis aims to identify conditions and parameters that alter the cloud properties and precipitation characteristics to foster scientific knowledge of such processes and improve future model evaluations.

 
natural vs anthropogenic sources and the influence of the terrestrial imput at the sea offshore the Sarno River (Naples Bay, Italy)
Authors: buonocunto francesco paolo , mali matilda , milia alfonsa , di leo antonella , ferraro luciana , giandomenico santina , giordano laura
Published: March 2022

Southeast Naples Bay represents a wide continental shelf environment with terrestrial sediment supply mainly from the Sarno River. The Sarno river basin, including about 500 km2 of the alluvial plain, is located in Campania Region (SW Italy) between the volcanic complex of Somma-Vesuvio (on the NW), the Sarno Mts. (on the NE), the Lattari Mts. (on the S), the Tyrrhenian sea (on the W) and the Picentini Mts. (on the E). Currently, the Sarno river, partially used for irrigation, is affected by an extreme environmental pollution as a result of the outflow of industrial waste. Consequently, the area of the Naples Bay is influenced by sediment loads derived from the Sarno River (Albanese et al., 2013; De Pippo et al., 2006).

Seventy-one samples collected by van Veen grab) along a transect (long about 9 km) perpendicular to the coast has been used to evaluate: 1) the relative influences of parent lithology and anthropogenic effects offshore the Sarno river in the Southeast part of Naples Bay; and 2) the extension of the influence of the river in the submarine area. Different environmental indicators were selected for the contamination assessment such as total nitrogen (TN) and phosphorus (TP), total organic carbon (TOC), grain size of particles, metals, priority polycyclic aromatic hydrocarbons (16 USEPA, PAHs), total petroleum hydrocarbon (TPHs), volatile organic compounds (VOCs), polychlorinated biphenyls (PCBs), pesticides (OCPs) and organotin compounds (OTs).

Two different statistical techniques, Principal Component Analysis and factorial Analysis of Variance (ANOVA), allowed us to recognize areas with different pollution features. The results of this study compared to the published onshore data permitted us to evaluate natural versus anthropogenic sources and to delimit the influence area of the Sarno River supply into the Naples Bay.

References:

Albanese, S., Iavazzo, P., Adamo, P., Lima, A., De Vivo, B. (2013) Assessment of the environmental conditions of the Sarno River Basin (South Italy): a stream sediment approach. Environ. Geochem. Health 35, 283–297.

De Pippo, T., Donadio, C., Guida, M., & Petrosino, C. (2006) The case of Sarno river (Southern Italy). Effects of geomorphology on the environmental impacts. Environmental Science and Pollution Research, 13(3), 184–191.
Finite-Volume Flux Reconstruction and Semi-Analytical Particle Tracking for Finite-Element-Type Models of Variably Saturated Flow in Porous Media
Authors: Selzer Philipp , Allgeier Jonas , Therrien René , Cirpka Olaf A.
Published: March 2022

Particle tracking is the most direct and a computationally efficient method to determine travel times and trajectories in subsurface flow modeling. Accurate and consistent particle tracking requires element-wise mass conservation and conforming velocity fields, which ensure continuity of the normal-flow component on element boundaries. These conditions are not met by standard finite-element-type methods. Despite this shortcoming, finite-element-type methods are often used in subsurface flow modeling because they continuously approximate the potential-head field and can easily handle unstructured grids and full material tensors. Acknowledging these advantages and the wide-spread use of finite-element-type models in subsurface flow simulations, we present a novel postprocessing technique that reconstructs a cell-centered finite-volume approximation from a finite-element-type primal solution of the variably-saturated subsurface flow equation to obtain conforming, mass-conservative fluxes. Using the resulting velocity fields, we derive a semi-analytical, parallelized particle tracking scheme applicable to triangular prisms, which leads to consistent and mass-conservative trajectories and associated travel times. Compared to other postprocessing schemes, our flux reconstruction is stable, robust, and fast as it only solves a linear elliptic problem on the order of the number of elements, whereas the original flow problem was transient and non-linear. The methods are implemented as postprocessing codes and linked to the finite-element-type code HydroGeoSphere, but could also be linked to any other software yielding a solution of variably saturated flow in porous media on triangular prisms. The postprocessing codes can handle catchment-scale models including heterogeneous materials, geometries, and boundary conditions, and facilitate to track a million particles through a catchment in just a few minutes on a Standard-PC in Matlab. The approach is described by Selzer et al. (2021).
The Bláfjall tuya in North Iceland, morphological characteristics and effect of ice flow and icesheet slope on edifice form  
Authors: Sigurbergsdóttir Anna Margrét , Gudmundsson Magnús Tumi
Published: March 2022

Tuyas are basaltic to intermediate glaciovolcanic edifices, formed in a body of meltwater within an ice sheet, in an ocean or a lake. The most common tuya stratigraphy consist of a lowermost layer or a mound of pillow lava, overlain by hyaloclastite tuffs and capped by a layer of subaerially-formed, horizontally bedded, lava flows. The parts of the lava flows more distant from the vent are built on flow-foot breccias, with the transition from subaerially-formed lava flows and breccias being a distinct stratigraphic boundary: the passage zone. The elevation of the passage zone marks the water level in the englacial lake into which the evolving tuya was built. At many locations the elevation of the passage zone appears to vary considerably from one location on a tuya to another. Some tuyas are elongated. One idea is that the elongation is predominantly in the direction of ice flow at the time of eruption.

By studying tuyas through aerial photography, satellite imagery and ground observations, the edifices variations in the elevation of the passage zone can be studied. This provides information on the eruption processes and environmental conditions at the time of formation.  We have analyzed the variation of passage zone elevation with distance along strike of a selected set of tuyas in Iceland. These include Bláfjall, located in Northern Iceland. It was formed within a Pleistocene ice sheet a continuous, prolonged eruption, or in a series of eruptions, closely spaced in time. The lava cap reaches a maximum thickness of approximately 100 m but is only a few meters to a few tens of meters thick on average, showing clear signs of influence from the ice sheet. Apparently, both the thickness of the ice sheet and the direction of ice flow direction exerted major control on the height and elongation of the Bláfjall tuya. The eruption took place well to the north of the ice divide at the time, and the flow of ice was predominantly from south to north, with the elongated structure of the tuya oriented parallel to the flow of the ancient glacier. The thickness of the lava cap is greatest in the north part and generally decreases towards south. This is despite the fact that the elevation of the mountain increases southwards. This indicates that the northern part is mostly formed by an advancing lava delta, propagating in the direction of ice flow and that the level of the water body present at the end of the advancing lava delta become progressively lower towards north. This suggests a sloping ice sheet at the time of formation, or possibly a receding ice sheet, leading to gradual thinning with time as the eruption progressed.   
Using artificial moulins to characterise englacial R-channels
Authors: Pohle Annegret , Werder Mauro A. , Gräff Dominik , Farinotti Daniel
Published: March 2022

The englacial and subglacial drainage system exerts key controls on glacier dynamics.  However, due to its inaccessibility, it is still only poorly understood and more detailed observations are important, particularly to validate and tune physical models describing its dynamics.

By creating artificial glacier moulins - boreholes connected to the subglacial drainage system and supplied with water from surface streams - we present a novel method to monitor the evolution of englacial hydrological systems with high temporal resolution.  Here, we use artificial moulins as representations for vertical, pressurised, englacial R-channels.  From tracer and pressure measurements we derive time series of the hydraulic gradient, discharge, flow speed and channel cross-sectional area.  Using these, we compute the Darcy-Weisbach friction factor, obtaining values which increase from 0.1 to 13 within five days of channel evolution (corresponding to a Manning friction factor of 0.03 to 0.3 s m-1/3).

Furthermore, we simulate the growth of the channel cross-sectional area using different temperature gradients.  The comparison to our measurements largely supports the common assumption that the temperature follows the pressure melting point.  The deviations from this behaviour are analysed using various heat transfer parameterisations to assess their applicability.

Finally, we discuss how artificial moulins could be combined with glacier-wide tracer experiments to constrain parameters of subglacial drainage more precisely. The presented approach allows to accurately quantify the englacial transit time of the tracer and thus, in turn, to quantify the subglacial transit time; something which has not been achieved to date.
Aerosol-induced Dynamical perturbation of the stratosphere: The 2017 Pacific Northwest Pyrocumulonimbus Event
Authors: Doglioni Giorgio , Aquila Valentina , Das Sampa , Colarco Peter R. , Taha Ghassan , Lattanzi Gianluca , Zardi Dino
Published: March 2022

The Pacific Northwest pyrocumulonimbus Event (PNE) took place in British Columbia during the nighttime hours between the 12th and 13th of August 2017. Several pyroconvective clouds erupted in this occasion, and released in the upper troposphere/lower stratosphere unprecedented amounts of carbonaceous aerosols (300 ktn). The stratospheric aerosol plume persisted in the stratosphere for several months, while gradually rising up to 22 km and dispersing around the entire northern hemisphere. In this study, we use the Goddard Earth Observing System Atmospheric General Circulation Model (GEOS AGCM) to study the pertubations that the aerosol plume from the PNE event induced on the stratospheric meteorology. Our simulations include the radiative interactions of aerosols, so that their impacts on temperatures and winds are explicitly simulated . In this work, we show how the presence of the carbonaceous aerosols from the PNE event triggers the formation and maintenance of a synoptic scale stratospheric anticyclone. We follow this disturbance considering the potential vorticity anomaly and the brown carbon aerosol loading and we describe its dynamical structure and evolution in time. 
The analysis presented here shows that the simulated anticyclone undergoes daily expansion-compression cycles governed by the radiative heating, which are directly related to the vertical motion of the plume, and that the aerosol radiative heating is essential in maintaining the anticyclone itself.