bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-cost airbox network and Gaussian plume modelling to assist air quality policy-making at the local scale: Shexian County, Hebei Province, China
Authors: Zhang Jun , Hensen Arjan , Seignette Paul , Yu Dan
Published: March 2021

High air pollution levels pose a threat to both human health and ecosystem vitality in Hebei Province, NE China. Although air quality changes are monitored hourly with high-end equipment at the provincial scale (197 stations for 187,693 km2) it is difficult for individual counties or cities to improve local air quality based on regional-scale information. The Sino-Dutch Technology Transfer & Training Project established a monitoring network of 43 low-cost air-boxes and 11 standard meteorological stations in Shexian county, Handan city (~ 1500 km2) to measure atmospheric concentrations of PM10, PM2.5, CO, SO2, NO2 and O3 at 1-min intervals from January 2020 onwards. Data from these stations were evaluated in real time using the TNO Gaussian plume model. The model provides point emission levels of PM10, PM2.5 and CO at 10-min intervals after calibration against measured concentrations. Based on a 2019 pollution source inventory, 21 major source areas were identified and used to derive an optimized source map for model input – including a large steel company, a coal-fueled power plant, different industrial complexes (cement, coking plant for ore smelting), as well as the densely populated city centre, rural residential areas, and a busy highway. The model performs source optimization using concentration data for all 43 stations and subsequently calculates the contributions of individual sources for each monitoring station to see to what extent the source map explained observed concentrations. Full network operation started in July 2020. Based on a one-month test period (August 2020), the steel company and coking plant were estimated to contribute ~25% of the total area’s PM-emissions. The central city area contributed ~10% and 17% of total PM- and CO-emissions, respectively, mostly due to construction activity and traffic. Repeating the exercise for the two provincial monitoring stations that also had high-end equipment in place in the downtown area gave inferred average urban contributions to measured concentrations as high as 60–62.5% for PM10 and PM2.5 versus 48% for CO. The steel factory contributed an estimated 9–11% for PM10 and PM2.5 at these locations and a cement factory 13% for CO. The combined results underline the importance of taking spatial variability of emission sources into explicit account in complex industrialized cities. Moreover, the combination of a low-cost airbox real-time monitoring network with emission apportionment modeling will allow local policy-makers to take proper actions towards reducing air pollution levels at the local scale.
Groundwater Flow Simulation in a Confined Aquifer Using Meshless Weak Strong Form
Authors: Das Sanjukta , t i Eldho
Published: March 2021

Understanding the complex groundwater flow behaviour is of utmost importance for a better and quicker management of groundwater. A thorough study of flow behaviour can be attained by modeling. Numerical simulation models have been proven to be an effective means of modeling of groundwater. The state-of-art meshfree simulation models, demonstrated in the various studies, have a clear advantage of allaying the meshing and remeshing complications. Meshless methods can be grouped into weak, strong and weak strong form methods. The strong form methods are truly meshfree, straightforward and efficacious, but they require a special treatment for the derivative boundaries. This imposes a limitation on the strong form methods in the application of groundwater studies, as the aquifers predominantly involve natural boundary conditions. The weak form methods, though effective in handling the derivative boundary conditions, require more computational time. The meshless weak strong (MWS) form combines the strengths of the strong and weak forms to obtain efficient and robust solutions with a lesser computational cost. This study aims at investigating the unexplored area of the applicability of the theoretically potent MWS method to the groundwater flow problems. In this context, the MWS model is developed by integrating the Meshless Local Petrov Galerkin (MLPG) method and the Radial Point Collocation Method (RPCM). The developed MWS model is applied to the flow studies in a hypothetical confined aquifer and is observed to result in fruitful solutions. Highlighting the advantages of the MWS method, satisfactory results could be obtained in atleast 30% lesser computational time compared to the weak form model. Thus, MWS method can be considered as an efficient tool to simulate large scale groundwater flow problems.
Subglacial Discharge of the Greenland Ice Sheet from Basal Melt
Authors: Karlsson Nanna Bjørnholt , Solgaard Anne M , Mankoff Kenneth D , Gillet-Chaulet Fabien , MacGregor Joseph A. , Benn Douglas I. , Hewitt Ian , Fausto Robert S.
Published: March 2021

The total mass balance of ice sheets is determined using estimates of ice volume change from satellite altimetry, measurements of gravity changes, or by differencing solid ice discharge and surface mass balance. The basal melt is only implicitly included in the first two and entirely neglected by the last method. Here, we show that the basal mass loss of the Greenland Ice Sheet is a non-negligible component of the total mass budget. We estimate that the basal melt is 21.4 +4.4/-4.0 Gt per year corresponding to 8% of the ice sheet’s total mass balance. The basal melt is composed of three separate terms; melt caused by frictional heat, geothermal heat and heat from surface meltwater, respectively, and the basal friction term is responsible for half of the basal melt.

Importantly, the geothermal and friction heat are active year round. This implies that a quantifiable volume of freshwater is discharged into the Greenlandic fjords during the winter where the ice-fjord interactions often are assumed dormant. Here, we present basal melt volumes from different outlet glaciers that discharge into Greenlandic fjords. We compare the basal melt to the freshwater volumes generated by surface meltwater, and identify locations where basal melt volumes are comparable to surface meltwater during the winter.
Estimating extreme sea levels combining systematic observed skew surges and historic record sea levels
Authors: Saint Criq Laurie , Hamdi Yasser , Gaume Eric , Ouarda Taha B.M.J.
Published: March 2021

The estimation of the sea levels with a high return period is crucial for coastal planning and the assessment of coastal flooding risk. Coastal facilities are designed to very low probabilities of failure and hence the design values are affected by significant uncertainties. Some recent coastal floods due to exceptional surges suggest that the design performed with the current statistical approaches may sometimes be significantly underestimated. This presentation is a contribution to the use of historical observations to improve the estimation of extreme sea levels. Historic records consist in observed major sea level values. The corresponding skew surges may be estimated but the exhaustiveness of historical skew surges, which is an essential criterion for an unbiased statistical inference cannot be guaranteed. . Indeed, Extreme skew surges can easily remain unnoticed if they occur at low or moderate high tide and do not generate extreme sea levels. This study proposes to combine, in a single Bayesian inference procedure, series of measured skew surges for the recent period and extreme sea levels for the historic period. The method is tested on four sites (tide gauges) located on the French Atlantic and Channel coasts. The proposed method appears to provide unbiased quantile estimates and to be more reliable than previously proposed approaches to include historic records in coastal sea level or surge statistical analyses.
On the role of atmospheric feedbacks in sustaining the anomalous warmth of the MIS-11 interglacial
Authors: Crow Brian , Prange Matthias , Schulz Michael
Published: March 2021

Historical estimates of the melt rate and extent of the Greenland ice sheet (GrIS) are poorly constrained, due both to incomplete understanding of relevant ice dynamics and the magnitude of forcing acting upon the ice sheet (e.g., Alley et al. 2010). Previous assessments of the Marine Isotope Stage 11 (MIS-11) interglacial period have determined it was likely one of the warmest and longest interglacial periods of the past 800 kyr, leading to melt of at least half the present-day volume of the Greenland ice sheet (Robinson et al. 2017). An enhanced Atlantic meridional overturning circulation (AMOC) is commonly cited as sustaining the anomalous warmth across the North Atlantic and Greenland (e.g., Rachmayani et al. 2017), but little is known about potential atmospheric contributions. Paleorecords from this period are sparse, and detailed climate modelling studies of this period have been heretofore very limited. The climatic conditions over Greenland and the North Atlantic region, and how they may have contributed to the melt of the GrIS during MIS-11, are therefore not well understood. By utilizing climate simulations with the Community Earth System Model (CESM), our study indicates that changes in atmospheric eddy behavior, including eddy fluxes of heat and precipitation, made significant contributions to the negative mass balance conditions over the GrIS during the MIS-11 interglacial. Thus, accounting for the effects of atmospheric feedbacks in a warmer-than-present climate is a necessary component for future analyses attempting to better constrain the extent and rate of melt of the GrIS.
Aerosol-weather-climate interactions in highly polluted regions 
Authors: Gao Meng
Published: March 2021

With rapidly expanding economic and industrial developments and tremendous increases in energy consumption, China and India are facing serious aerosol pollution, posing great threat to human health. Aerosols also modulate the climate and ecosystems via aerosol-cloud-radiation interactions. Yet, the poor understanding of aerosol pollution in Asia and its interactions with climate impedes the design and implementation of effective pollution control measures. Combining atmospheric modeling and observations, we demonstrated that the aerosol interactions with radiation and clouds contributed in important ways to intensification of the aerosol enhancements in North China. We manifested also how assimilation of PM2.5 in winter haze periods can improve model predictions and that these improved predictions can reduce significantly the uncertainties in health impacts and estimates of aerosol radiative forcing. It was also demonstrated that the conditions of the ocean temperature in fall can be effectively used to predict the severity of Indian winter haze, which provides useful implications for pollution control at least a season in advance.
Megacrysts of “bubbled” kaersutite in the Neogene-Quaternary of Western Syria: evidence of crystallization in a boiled melt/fluid?
Authors: Sharkov Evgenii , Bogina Maria , Chistyakov Alexey
Published: March 2021

The territory of Syria is a classic area of intraplate Neogene-Quaternary plateau basaltic magmatism (Ponikarov et al., 1969; Sharkov, 2000; Lustrino, Sharkov, 2006; Trifonov et al., 2011, etc.). These basalts belong to the Afro-Arabian large igneous province (LIP) (Ernst, 2014), whose origin, according to geophysical data, is related to the ascent of a mantle thermochemical plume that originated at the liquid iron core-silicate mantle boundary of (Hansen et al., 2012).

The basalt plateaus of Syria have a similar structure and are formed by numerous basaltic flows, as well as scoria and pyroclastic cones, often containing mantle xenoliths. Approximately 80% of them are represented by green spinel lherzolites and harzburgites, and subordinate amount (~20 %) of xenoliths belong to black series (hornblendite, hornblende clinopyroxenites, clinopyroxenites, phlogopitites, etc., as well as megacrysts of kaersutite, clinopyroxene, ilmenite, sanidine, etc.). Some of the kaersutite megacrysts have unusual “bubbled” structure, containing oval cavities up to 3-4 mm in diameter. We believe that these xenoliths are fragments of the upper cooled margin of the mantle plume above the adiabatic melting zone (Sharkov et al., 2017). Thus, they probe substance of mantle plume and bear important information about the processes within its interior.

As previously shown (Sharkov et al., 2017), the black series rocks were formed from a melt/fluid released fluid during the incongruent ("secondary") melting of the mantle plume head at the final stage of the magmatic system evolution. The crystallization of this fluid-supersaturated melt could be accompanied by its retrograde boiling, which led to the appearance of "bubbled" crystals.

 
Presence and significance of backstops in the overriding plate during the megathrust earthquake cycle
Authors: D'Acquisto Mario , Broerse Taco , Govers Rob
Published: March 2021

Seismological and geodetic observations indicate that similar physical processes are active at different subduction margins and provide information about the deformation at the different stages of the earthquake cycle. We analyze geodetic observations along sections of the South American subduction zone during the inter-seismic stage. Results show that overriding plates shorten from the trench to a “backstop”, where horizontal inter-seismic velocities become close to zero. In most, but not all regions, the backstop location from trench-perpendicular GPS velocities agrees with that from trench-parallel velocities. The distance of the backstop from the trench varies along the western South America margin. Backstop locations shows some correlation with gradients in the effective elastic thickness of the overriding plate. An apparently conflicting observation is that co-seismic and early post-seismic GPS-displacements during the 2010 Maule earthquake extended well beyond the backstop into eastern South America. Similarly conflicting observations were made in the overriding plate of the 2004 Sumatra earthquake and the 2011 Tohoku earthquake.

We use cyclic 3D numerical models with dynamically driven co-seismic and afterslip to test the hypothesis that lateral contrasts in the thickness and/or elasticity of the overriding plate explain the observations. The model setup allows us to explore the sensitivity of geodetically observable surface motion to the mechanical structure of the subduction system during all parts of the earthquake cycle. We conclude that the observations can be explained by a lateral contrast. Such contrast restricts inter-seismic horizontal velocities in the region between the trench and the backstop, controlling their gradient, while allowing deformation due to coseismic slip and afterslip to reach well into the far field. One particularly interesting finding from our models is that stress accumulation in the overriding plate is controlled by the distance to the backstop.
Discrete and continuous conceptual models of fault zones.
Authors: Manzocchi Tom
Published: March 2021

Faults can control the large-scale properties of rock volumes through their behaviour as flow conduits and/or barriers or by localising geomechanical effects. Hence, often the fidelity of a numerical model of faulted site relies on the accuracy with which the fault zone is represented.  There are two distinct factors that must be considered in a modelling study: first, does the model contain the most relevant characteristics of the fault that influence the behaviour of interest; and second, are these characteristics assigned realistic and representative values that capture both their natural variability and the uncertainty with which they can be determined for the specific case of interest. These two factors are contained in the conceptual fault model and choice of modelling proxy-properties, respectively.

In recent years, two classes of conceptual fault zone model have dominated the description of fault zones, broadly characterised by either a continuous or a discrete approach. Continuous fault zone properties (e.g. fault core and damage zone thickness, displacement partitioning statistics) often show high variability which many modelling studies attempt to capture by running multiple model containing property values sampled from the distribution. Discrete descriptions focus on the presence of individual fault zone elements (e.g. shale smears, relay zones), and models guided by a discrete conceptual model attempt to place representative frequencies of elements. A single discrete model might contain the same property distributions as an ensemble of continuous models yet, because it contains a representative frequency of different elements, its behaviour might lie beyond the extreme behaviour of the continuous ensemble. Hence, the manner in which a geologist’s conceptual model is represented in a modeller’s numerical model can be hugely important for the outcome of the study, and it is in the interest of both modellers and geologists to ensure that they have a correct understanding of the other’s part of the process.
Coupling large and small ring infiltration experiments for investigating preferential flow
Authors: Lassabatere Laurent , Di Prima Simone , Concialdi Paola , Abou Najm Majdi , Stewart Ryan D. , Bagarello Vincenzo , Iovino Massimo , Castellini Mirko , Fernández-Gálvez Jesús , Pollacco Joseph , Yilmaz Deniz , Angulo-Jaramillo Rafael
Published: March 2021

Preferential flow is more the rule than the exception. Water infiltration is often led by preferential flow due to macropores, specific soil structures (e.g., aggregates, macropore networks), or lithological heterogeneity (occurrence of materials with contrasting hydraulic properties). Water infiltration in soils prone to preferential flow strongly depends on soil features below the soil surface, but also the initiation of water infiltration at the surface. When the macropore networks are not dense, with only a few macropores intercepting the soil surface, water infiltration experiments with ring size in the order of 10-15 cm diameter may overlook sampling macropore networks during some infiltration runs, minimizing the effect of macropore flow on the bulk water infiltration at the plot scale.

In this study, we investigated the effect of ring size on water infiltration into soils prone to preferential flow. We used two ring sizes: small (15 cm in diameter) and large (50 cm in diameter). By doing so, we hypothesized that the large rings, sampling a more representative soil volume, will maximize the probability to intercept and activate a macropore network. In contrast, the small rings may activate the macropore network only occasionally, with other infiltration runs mainly sampling the soil matrix. Thus, the small rings are expected to provide more variable results. On the other hand, the large rings are expected to provide more homogeneous results in line with the soil's bulk infiltration capability, including all pore networks at the plot scale.

Three different sites were sampled with varying types of preferential flow (macropore-induced versus lithological heterogeneity induced). The experimental plan included inserting large rings at several places in the experimental sites with a dozen small rings nearby to sample the same soil. All the rings were submitted to a similar positive constant water pressure head at the soil surface. The cumulative infiltrations were then monitored and treated with BEST algorithms to get the efficient hydraulic parameters. Note that the cumulative infiltration could not be compared directly since lateral water fluxes varied in extent and geometry between the different ring sizes. The impacts of the ring size on the magnitude of cumulative infiltration and related estimated hydraulic parameters were discussed. Our results demonstrated the impact of ring size but also the dependency of such effect on the site and the type of flow.

Our results contribute to understanding preferential flow in heterogeneous soils and the complexity of its measure using regular water infiltration devices and protocols.
Disentangling spatiotemporal characteristics of six different unregulated streamflow stations in India
Authors: Pant Tarun , Yeditha Pavan kumar , Agarwal Ankit , Rathinasamy Maheswaran
Published: March 2021

With the increasing stress on water resources for a developing country like India, it is very much pertinent to study how the water resources are varying with time and investigate the dominant streamflow patterns for carrying effective planning and management activities. In this study, we attempt to investigate the spatiotemporal characterization of streamflow of six unregulated catchments in India and also quantify the impact of precipitation changes and four climate indices, namely, Niño 3.4, IOD, PDO and NAO on streamflow. Initial analysis of streamflow and precipitation was carried out using Mann Kendall and step change detection methods. Temporal variability of streamflow and its association with precipitation and climate indices was unraveled using continuous wavelet transform and Wavelet coherence respectively. Cross-wavelet transform was also used to capture the coherent relationships and phase relationships between streamflow and climate indices. The results of the study reveal an in-phase relationship between precipitation and streamflow. The analysis also considers that streamflow is mostly affected by Niño 3.4 and PDO indices. Based on the results of this work, better understanding of interrelationship between the streamflow and precipitation was well captured using Wavelet coherence when compared to Cross wavelet. It was observed that almost all basins had showed the effect of changes in precipitation on streamflow. Based on these observations, it is clear that WTC can be used for understanding interrelationship between variable when compared to XWT and gives better insights regarding the interrelationship
Exploring the possible meridional temperature gradient of Early Eocene Climatic Optimum with an energy balance model
Authors: Kelemen Fanni Dora , Ahrens Bodo
Published: March 2021

Early Eocene Climatic Optimum (EECO, ~53-51 million years) is one of the past warm periods, associated with high CO2 concentrations (~900-2500 ppmv), which can serve as an analogue for our possible future, high C02 climate. One notable feature of this hothouse climate state is the weaker meridional temperature gradient relative to pre-industrial values. This have been confirmed by both proxies and models, but the extent of the temperature gradient still requires more research. Models are challenged to reproduce the stronger than present day polar amplification signal, and it is also shown that high latitude proxy data are often influenced by seasonal bias. Thus, there is an uncertainty regarding both the observed and modelled meridional gradient and the mentioned issues complicate also the comparison between modeled and proxy data.

In our work we aim to investigate the EECO period with a simple energy balance box model and apply the maximum entropy production principle to explore the possible scenarios of meridional temperature gradients. We find that the maximum entropy production principle could be beneficial in the paleoclimate context since it has the utility to give an accurate prediction for non-equilibrium systems with the minimal amount of information. We also assess the heat transport signaled by proxy data and by state-of-the-art model outputs in accordance to our theoretical constrains based on the idealized test case.
How is the atmospheric residence time of evapotranspired water altered with a dried-up lake or a forest restoration scenario and what is the impact on precipiation?
Authors: Wei Jianhui , Arnault Joël , Zhang Zhenyu , Laux Patrick , Fersch Benjamin , Wagner Sven , Dong Ningpeng , Yang Qianya , Yang Chuanguo , Yu Zhongbo , Kunstmann Harald
Published: March 2021

Land surface characteristics and processes may have complex interactions with the physical and dynamical processes of the atmosphere. However, adequate methods for systemically understanding individual processes of the nonlinearly coupled land-atmosphere continuum are still rare. Therefore, in this study, the age-weighted evaporation tagging approach of Wei et al. (2016) and the three-dimensional online atmospheric water budget analysis of Arnault et al. (2016) were implemented into the Weather Research and Forecast (WRF) model. In addition to the total and tagged atmospheric water states of matter, the latter approach was further extended for age-weighted tagged atmospheric water states of matter, thereby providing a prognostic equation of the residence time of state variables in the atmospheric water cycle. This extension allows to systematically quantify the fate of evaporated and transpired water in terms of magnitude, location, composition, and residence time. The extended WRF model was tested for a land use and land cover change study for the Poyang Lake basin, the largest freshwater lake in China. Two hypothetical scenarios, i.e., a dried-up lake and a forest restoration scenario, were simulated and then compared to a real-case control simulation using the original land-use data. The results of the basin-scale precipitation recycling in the context of evapotranspiration partitioning and the modified atmospheric water cycle due to both scenarios will be presented and discussed. We conclude that our newly developed modelling framework and the proposed analysis strategy have the potential to be applied for better understanding and quantifying the nonlinearly intertwined processes between the land and the atmosphere.

References:

Arnault, J., Knoche, R., Wei, J., & Kunstmann, H. (2016). Evaporation tagging and atmospheric water budget analysis with WRF: A regional precipitation recycling study for West Africa. Water Resources Research, 52(3), 1544–1567. https://doi.org/10.1002/2015WR017704

Wei, J., Knoche, R., & Kunstmann, H. (2016). Atmospheric residence times from transpiration and evaporation to precipitation: An age-weighted regional evaporation tagging approach. Journal of Geophysical Research: Atmospheres, 121(12), 6841–6862. https://doi.org/10.1002/2015JD024650
Testing different remote sensing compositing periods for SOC content extraction in areas across Germany
Authors: Zepp Simone , Bachmann Martin , Möller Markus , van Wesemael Bas , Steininger Michael , Wiesmeier Martin , Heiden Uta
Published: March 2021

High spatial and temporal soil information is crucial to analyze soil developments and for monitoring long term changes to avoid soil degradation. A sufficient soil organic carbon (SOC) content is one of the key soil properties to achieve sustainable high productivity of soils, soil health and increased agroecosystem resiliency. For the usage of remote sensing approaches, naturally exposed soils in Germany occur rarely. Mainly agricultural regions can provide areas of exposed soils for short periods of time during a year. The Soil Composite Mapping Processor (SCMaP) is a fully automated approach to make use of per-pixel based bare-soil compositing to overcome the issue of limited soil exposure based on multispectral Landsat (TM 4, ETM 5, ETM+ 7 and OLI 8) imagery for individually determined time periods between 1984 and 2019.

Due to the high spatial and temporal resolution the SCMaP soil reflectance composites contain a considerable potential to derive detailed soil parameters as the SOC contents of exposed soils to add information to existing soil maps on field scale for areawide applications. Besides the soil reflectance composites several field soil samples provided by different federal authorities build the data base for the SOC modeling. Machine learning (ML) algorithms incl. Partial Least Squares and Random Forest regression with various inputs and set-ups are used and applied for several test areas in Germany. Furthermore, the capabilities of different compositing lengths (5-, 10- and 30-years) to derive spatial SOC contents are tested. The results and the validation of the different ML approaches and compositing lengths will be shown, providing insight into the benefits of this approach.
Updating the soil hydraulic parameters in a 3D subsurface model
Authors: Brandhorst Natascha , Neuweiler Insa
Published: March 2021

Soil moisture is an important variable for land surface processes. To make good model predictions of soil moisture, the flow processes in the subsurface need to be captured well. Flow in the subsurface strongly depends on the soil hydraulic parameters. Information about model parameters is often not available, at least not for the entire domain of interest. The resulting parameter uncertainty needs to be accounted for in the applied model. Data assimilation can account for parameter and model errors as well as for all other possible sources of uncertainty if observations are available that can be used to condition the model states. Thus, the parameter uncertainty might be reduced and model predictions improved. However, including the parameters increases the size of the state vector and thus the computational burden. Especially for large models, this can be a problem. Furthermore, the updates can produce unphysical parameter combinations which in unsaturated zone models often lead to numerical problems.

In this work, we test the effect of updating the soil hydraulic parameters along with soil moisture in a 3D subsurface hillslope model. We use the ensemble Kalman filter for data assimilation and synthetic observations of soil moisture. In a similar study using a 1D unsaturated flow model, parameter updates were found to be the best way to handle parameter uncertainty. Updating parameters resulted in improved predictions of soil moisture, although not necessarily in more realistic model parameters. The parameter updates should rather be considered a method of treating parameter uncertainty than a method for parameter identification. In the 1D settings, updating all uncertain parameters led to the best results. Whether this still holds and is feasible for a more complex 3D model is the question addressed in this presentation.
Documenting isobaric cooling in the lower crust using cordierite breakdown textures (Mont Mary nappe, Western Alps)
Authors: Ballèvre Michel , Poujol Marc , Rousseau Selim , Manzotti Paola
Published: March 2021

Intracrystalline diffusion is an efficient mechanism in high-grade rocks. Therefore, growth zoning in garnet is erased and the evidence for prograde path is lost. However, information recorded by the textures may store significant clues for deciphering part of the P-T path. An example is provided here from the migmatitic paragneisses from the Mont Mary nappe (Western Alps).

The latter is made of a pre-Alpine basement consisting of an upper and a lower unit. The upper unit is made of paragneisses, marbles and amphibolites similar to those of the Valpelline Unit and of the Ivrea Zone. The lower unit displays granitic orthogneisses, paraschists (with muscovite, biotite, garnet with local occurrences of staurolite, kyanite and andalusite) (Dal Piaz et al. 2015). In this unit, we discovered a hectometre-sized volume with no Alpine overprint, preserving migmatitic paragneisses, the topic of this study.

The paragneisses display quartzo-feldspathic leucocratic layers interpreted as crystallized melts. The leucosomes are separated by biotite- and sillimanite-rich layers, with conspicuous garnet porphyroblasts. In addition, fresh cordierite crystals are found in these layers. Sillimanite included in garnet rims has the same orientation than the one in the matrix. There, the foliation is defined by the shape fabric of biotite and sillimanite, wrapping both garnet and cordierite crystals.

Such textures may be used to propose a P-T path. A sequence of prograde reactions, including dehydration-melting of muscovite, then biotite, result in the production of a large amount of sillimanite. Garnet growth was continuing during incongruent melting. However, intracrystalline diffusion has erased the prograde chemical zoning, as well as the distribution and shape of mineral inclusions. The late replacement of garnet and cordierite by biotite and sillimanite indicates near-isobaric cooling, also recorded by chemical zoning along garnet rims.

Chemical data on coexisting minerals will be used to provide quantitative constraints on the P-T path. In addition, preliminary geochronological data suggest that detrital zircons grains were significantly reset during the HT metamorphism, which could have taken place c. 270 Ma ago. To conclude, the studied paragneisses offer another example of Permian near-isobaric cooling in the middle crust of the Adriatic plate.

Dal Piaz G.V., Bistacchi A., Gianotti F., Monopoli B., Passeri L., Schiavo A. & collaboratori (2015) – Note illustrative della carta Geologica d’Italia alla scala 1:50.000. Foglio 070, Monte Cervino. ISPRA, Servizio Geologico d’Italia, 070, 1-431.
Classification of moisture damage in layered building floors with GPR and neutron probe
Authors: Klewe Tim , Strangfeld Christoph , Ritzer Tobias , Kruschwitz Sabine
Published: March 2021

In 2019, 3.1 billion Euro of damage was caused by piped water, accounting for the largest share (53%) of building insurance claims in Germany. In the event of damage, the accurate determination and localization of water ingress is essential to plan for and perform efficient renovations. Neutron probes are already applied successfully on building floors to localize the source of damage and other affected areas. However, additional information about the depth of moisture penetration can only be obtained by the destructive extraction of drilling cores, which is a time- and cost-intensive procedure. With its high sensitivity to water and fast measurement procedure, Ground Penetrating Radar (GPR) can serve as a suitable extension to the neutron probe, enabling more precise characterization of common forms of moisture damage.

In this research project, we study the influence of common types of moisture damage in differing floor constructions using GPR and a neutron probe. A measurement setup with interchangeable layers is used to vary the screed material (cement or anhydrite) and insulation material (Styrofoam, Styrodur, glass wool, perlite), as well as the respective layer thickness. Every configuration is measured for the following main cases: 1) dry state; 2) with a damaged insulation layer and 3) a damaged screed layer.

The evaluation is focused on the extraction of distinctive signal features for GPR, which can be used to classify the underlying case of damage. Furthermore, possible combinations of these features are investigated using multivariate data analysis and machine learning in order to evaluate the influence of different floor constructions.

To validate the developed methods, practical measurements on real damage cases in Germany are carried out and compared to reference data obtained from drilling cores.
The impact analysis of traffic and meteorological factors on air pollution risk in Taiwan, Taipei City
Authors: Lin Yu-Ting , Lin Yuan-Chien
Published: March 2021

Air pollution has always been one of the serious issues around the world, not only related to the large-scale climate environment, but also related to local-scale vehicles-caused air pollutants in the city. Generally, diesel-burning vehicles emit NOX, SO2, CO; gasoline burning vehicles emit CO, CO2, NOX respectively. The common air pollutants CO and NOX are widely regarded as the primary traffic-caused air pollutants. Therefore in this study, we take vehicle detector data including car speed, car volume, lane occupy as well as meteorological data and the air pollutants concentration in consider. Firstly, we use the Stepwise Regression Model(SRM) to select the significant factors for the target air pollutants and predict them with multivariate linear regression. Secondly, we also combine Long Short-Terms Memory (LSTM) Model to simulate the highly nonlinear and unstationary complex chemical interaction between air pollutants. In this study we got high model accuracy performance in primary pollutants prediction (CO,NOX) by including the vehicle detector data with both Multivariate linear regression Model and LSTM model which conclude that the vehicle detector data can significantly improve the quality of model prediction. This process select the statistically significant factors of the pollutants, and also establishes a neural network model including traffic, meteorological factors and air quality which contribute to the air pollutants risk management of government agency.

Keywords: traffic pollutants, air quality, stepwise regression, LSTM model
High performance modular, compact and ruggedized processing system for airborne and balloon remote sensing instruments
Authors: Neubert Tom , Schardt Georg , Rongen Heinz , Zimmermann Egon , Gulde Thomas , Kretschmer Erik , Maucher Guido , Preusse Peter , Riese Martin , Ungermann Jörn , van Waasen Stefan
Published: March 2021

Observations from aircraft and balloons with remote sensing instruments are an important method to investigate processes within the Earth environment. These applications require powerful computing systems that must be developed or adapted for the measurement task and requirements. In particular, imaging spectrometers generate high data rates by almost 10,000 pixels at about 4,000 frames per second. Accordingly, high performance is needed to provide operational control and data processing with high data bandwidth and the capability to store this data also during long duration flights.

A modular processing system architecture based on modified industrial grade board components has been developed to meet these high requirements for processing power and storage capacity. The major advantages of this approach are flexibility, (re)programmability, modularity and module re-use in order to attain lower development time and costs. However, it is a challenge to design this processing system to be suitable for the harsh environments of aircraft or balloon applications in terms of temperature range, humidity and vibration.

With an efficient approach ruggedized characteristics are achieved using a conduction cooled design in combination with components based on VPX standard and customized backplane transition modules in order to reduce operational risk with necessary measures of mitigation techniques. This approach results in a processing system that combines hardware and software redundancies to assure system availability and reliability for long duration flights.

In this presentation the compact flight proven system design is presented that has been used in recent years for high spectral resolution limb-observations by the GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) spectrometer aboard the HALO and Geophysica high-altitude aircrafts. Various system configurations and performance results will be shown, which have been achieved in the current design and will be applied in future balloon campaigns.
Using emissions derived from atmospheric observations to inform the reported UK inventory
Authors: Manning Alistair , Redington Alison , O'Doherty Simon , Young Dickon , Say Dan , Arnold Tim , Rennick Chris , Wisher Adam , Spain Gerry , Frumau Arnoud , Forster Grant , Stanley Kieran , Vollmer Martin , Reimann Stefan , Arduini Jgor , Maione Michela , Schuck Tanja , Engel Andreas
Published: March 2021

Verification of the nationally reported greenhouse gas (GHG) inventories using inverse modelling and atmospheric observations is considered to be best practice by the United Nations Framework Convention on Climate Change (UNFCCC). It allows for an independent assessment of the nationally reported GHG emissions using a comprehensively different approach to the inventory methods. Significant differences in the emissions estimated using the two approaches are a means of identifying areas worthy of further investigation.

 

An inversion methodology called Inversion Technique for Emission Modelling (InTEM) has been developed that uses a non-negative least squares minimisation technique to determine the emission magnitude and distribution that most accurately reproduces the observations. By estimating the underlying baseline time series, atmospheric concentrations where the short-term impact of regional pollution has been removed, and by modelling where the air has passed over on route to the observation stations on a regional scale, estimates of UK emissions are made. In this study we use an extensive network of observations with six stations across the UK and six more in neighbouring countries. InTEM uses information from a Lagrangian dispersion model NAME (Numerical Atmospheric dispersion Modelling Environment), driven by three-dimensional, modelled meteorology, to understand how the air mixes during transport from the emission sources to observation points. The InTEM inversion results are submitted annually by the UK as part of their National Inventory Report to the UNFCCC. They are used within the UK inventory team to highlight areas for investigation and have led to significant improvements to the submitted UK inventory. The latest UK comparisons will be shown along with examples of how the inversion results have informed the inventory.
Sources of ice block falls at the Martian north polar scarps: detection from multi-temporal HiRISE image sets
Authors: Su Shu , Fanara Lida , Zhang Xin , Gwinner Klaus , Hauber Ernst , Oberst Jürgen
Published: March 2021

The North Polar Layered Deposits (NPLD), which consist of dusty water ice layers, have recorded the climatic variations of Mars. We use High Resolution Imaging Science Experiment (HiRISE) data (ground pixel size of up to ~0.25m/pixel) to study the morphology and current erosional processes at the NPLD scarps. Fanara et al. (1,2) have performed automated detection of the fallen ice blocks at the foot of scarps. Our aim is to search for their possible source areas.

We apply change detection techniques to multi-temporal images. The images are ortho-rectified using HiRISE Digital Terrain Model (DTM) and then co-registered to ensure subpixel alignment accuracy. Due to the low-sun conditions in Martian polar areas, the surface morphology can be revealed from cast shadows. In addition, HiRISE operates on a nearly sun-synchronous orbit, which means the images are taken at the same local time of day, providing good conditions for automatically detecting changes in shadow patterns of the ice-fragments.

The areas with changed shadows illustrate the spatial distribution of mass wasting activities. Our results show that most of the detached ice-fragments originate from the lower parts of the scarp, which are heavily affected by fracturing. Based on the detected changes, we will further investigate the characteristics of mass wasting and estimate the volume of the detached ice-fragments. The temporal and spatial distribution of detached ice fragments at different NPLD scarps can provide insights into the ice behavior and thus support modelling studies of viscous flow velocities (3), thermoelastic stresses (4) and climate variations of Mars. Ultimately, we intend to explore the evolution of the NPLD scarps by correlating long-term mass wasting characteristics with seasonal and morphological parameters.

 

References

[1] Fanara et al.,2020. Planetary and Space Science. 180, p.104733.

[2] Fanara et al.,2020. Icarus. 342, p.113434.

[3] Sori et al., 2016. Geophysical Research Letters, 43(2), pp.541-549.

[4] Byrne et al., 2017. EPSC, Vol. 11.
The effect of Forbush decreases on the polar-night HOx concentration
Authors: Mironova Irina
Published: March 2021

It is well-known that energetic particle precipitations during solar proton events increase ionization rates in the middle atmosphere enhancing the production of hydrogen oxide radicals (HOx) involved in the catalytic ozone destruction cycle. There are many studies where the contribution of energetic particles to the formation of hydrogen oxide radicals and ozone loss has been widely investigated. However, until now, there was no solid evidence that the reduction in galactic cosmic ray fluxes during a magnetic storm, known as Forbush-effect, directly and noticeably affects the polar-night stratospheric chemistry.
Here, the impact of the Forbush decrease on the behaviour of hydrogen oxide radicals was explored using the chemistry-climate model SOCOL.
We found that hydrogen oxide radical lost about half of its concentration over the polar boreal night stratosphere owing to a reduction in ionization rates caused by Forbush decreases after solar proton events occurred on 17 and 20 of January 2005. A robust response in ozone was not found. There is not any statistically significant response in (NOx) on Forbush decrease events as well as over summertime in the southern polar region.
The results of this study can be used to increase the veracity of ozone loss estimation if stronger Forbush events can have a place.

Reference: Mironova I, Karagodin-Doyennel A and Rozanov E (2021) , The effect of Forbush decreases on the polar-night HOx concentration affecting stratospheric ozone. Front. Earth Sci. 8:618583. doi: 10.3389/feart.2020.618583

https://www.frontiersin.org/articles/10.3389/feart.2020.618583/full

The study was supported by the Russian Science Foundation grant (RSF project No. 20-67-46016).
Multichannel FMCW lidar for imaging velocimetry and range finding
Authors: Gazizov Iskander , Zenevich Sergei , Benderov Oleg , Rodin Alexander
Published: March 2021

We present a concept of near-infrared FMCW lidar for real-time low-resolution imaging velocimetry and range finding of moving objects. One of the problems this instrument to challenge is the detection of unmanned aerial vehicles in an urban environment. The use of a lidar-based system is either in the detection of the object itself or of the wingtip vortices generated by rotating blades. A significant drawback of typical wind lidar is the long measurement time associated with the need to scan the area of ​​interest, therefore we propose an 8x2 matrix of receivers to reduce the total scan time. The main feature of the instrument is the use of commercially available components, including DFB lasers and single-mode fiber for the optical circuit, which can significantly reduce the cost of the device, as well as development time. Data processing and laser control are handled by the FPGA. The characteristics of the multichannel lidar are estimated based on ongoing testing of the single-channel prototype.

Acknowledgements

This work has been supported by the Russian Foundation for Basic Research grants #19-29-06104