bluuebunny/crossref_metadata_2025 huggingface dataset:
A Global-Scale Analysis of Hydrologic Extremes using Hidden Climate Indices
Authors: Renard Benjamin , Westra Seth , Kavetski Dmitri , Thyer Mark , Leonard Michael , McInerney David , Vidal Jean-Philippe
Published: March 2022

Hydrologic extremes (floods and intense precipitations) are among Earth’s most common natural hazards and cause considerable loss of life and economic damage. Describing their space-time variability in relation to climate is hence important for scientific and operational purposes. This presentation describes the use of an innovative probabilistic framework to jointly analyze global datasets of floods and extreme precipitations. This framework is based on the idea that the temporal variability of the data is induced by hidden climate indices that are unknown and therefore have to be estimated directly from the data. This is to be contrasted with the usual approach using predefined standard climate indices such as ENSO or NAO for this purpose. In statistical terms, a two-level hierarchical model is used. The first level jointly describes floods and intense precipitations, with hidden climate indices treated as latent variables. The second level describes the temporal variability of the hidden climate indices (including trend and persistence components), and the spatial variability of their effects.

This model is applied to station-based datasets describing seasonal maxima of streamflow and precipitation at the global scale, corresponding to more than 3,000 stations over a 100-year period (1916-2015). Several hidden climate indices governing the joint temporal variability of streamflow and precipitation data are identified. They affect floods and intense precipitations over large (continental) spatial scales and in a highly structured way. Overall these hidden climate indices do not present noticeable trend or persistence components, suggesting that they represent mostly interannual modes of variability. By contrast, when the same model is applied to precipitation data only, the estimated hidden climate indices are affected by stronger and mostly upward trends: this confirms that increasing intense precipitations do not identically translate into increasing floods, as highlighted by the latest IPCC report. Finally, we demonstrate that hidden climate indices can be predicted to some degree from atmospheric variables such as pressure, wind, temperature etc. This allows reconstructing the probability of occurrence of hydrologic extremes in the distant past using long reanalyses such as 20CR.
Forced modulations of Sahel rainfall at decadal timescales over the20th Century using CMIP6 models
Authors: Ndiaye Cassien Diabe , Mignot Juliette , Mohino Elsa
Published: March 2022

During the 20th Century, Sahel rainfall has experienced strong variability at decadal timescales, partly attributed to the internal variability of the climate system, mediated by changes in oceanic sea surface temperature (SST). However, a stronger emphasis has been more recently given to the role of external forcing. Thus, the attribution of past decadal modulations of Sahel rainfall is still under debate.

In this study, we propose a diagnostic of the contribution of external forcing to observed Sahel rainfall decadal modulations based on a correlation analysis. We apply it to six models of the sixth coupled model intercomparison project (CMIP6) in the whole 20th Century. Our results show that external forcings induce a weak amplitude of Sahel rainfall modulations in the models and these modulations are in general insignificantly correlated with the observed modulations. There are two notable exceptions: IPSL-CM6A-LR and INM-CM5-0 models.

With the IPSL-CM6-LR model, our results show that this correlation primarily arises from the role of anthropogenic aerosols. This effect is partly explained via the ocean mediated mechanism in particular the North Atlantic ocean and Mediterranean sea. In CanESM5 and CNRM-CM6-1 models, the Sahel rainfall decadal forced modulations are also dominantly due to anthropogenic aerosols, although not significantly correlated with the observations. In addition, the greenhouse gases (GHG) contribute significantly to the forced response of these models, which could explain partly the insignificant correlation of these CMIP6 models. 
Comparison of ground-based 11.072 GHz microwave observations of Arctic polar MLT ozone with SABER datasets
Authors: Newnham David , Clilverd Mark , Clark William , Kosch Michael , Verronen Pekka , Rogers Alan
Published: March 2022

Ground-based observations of the ozone (O3) emission line at 11.072 GHz have been made using the Ny Ålesund Ozone in the Mesosphere Instrument (NAOMI) at the UK Arctic Research Station (latitude 78°55’0” N, longitude 11°55’59” E).  Seasonally-averaged O3 vertical profiles in the mesosphere-lower thermosphere (MLT) region from 15 August 2017 to 15 March 2020 have been retrieved over the altitude range 62–98 km.  NAOMI measurements are compared with overlapping Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite observations.  The NAOMI and SABER data are binned into 3-month nominal ‘winter’ (15 December–15 March), ‘autumn’ (15 August–15 November), and ‘summer’ (15 April–15 July) periods.  The NAOMI observations show the same year-to-year and seasonal variabilities as the SABER 9.6 µm O3 data, and winter night-time and twilight volume mixing ratio (VMR) profiles agree to within the measurement uncertainties.  However, for autumn twilight conditions the SABER 9.6 µm O3 secondary maximum VMR is more than 50% higher than NAOMI.  Comparing the two SABER channels which measure O3 at different wavelengths and use different processing schemes, the 9.6 μm O3 autumn twilight VMR values for 2017–19 exceed the corresponding 1.27 μm data with the largest difference (58%) in the 65–95 km altitude range similar to the NAOMI observation.  Summer daytime SABER 9.6 μm mesospheric O3 VMR is also consistently higher than the 1.27 μm measurement, confirming previously reported differences between SABER 9.6 μm measurements and those made by other satellites.
Estimating groundwater storage changes for major river basins in France using a regional groundwater data set 
Authors: Hsu Kuei-Hua , Eicker Annette , Hasan Mehedi , Güntner Andreas , Longuevergne Laurent
Published: March 2022

The German Research Unit GlobalCDA has the goal to improve the predictive skills of hydrological models by combining remote sensing information using a calibration/data assimilation (C/DA) approach. In order to validate model results and to assess the success of the C/DA efforts, independent data sets are crucially needed, such as in-situ groundwater observations to assess the ability of the model to describe groundwater storage changes. The main challenge arising from such comparisons is to capture basin-scale groundwater storage from a set of in-situ GW observations settled in highly heterogeneous lithologies with irregular & non-homogeneous sampling. Furthermore, the conversion from groundwater (GW) level measurements to storage variations requires information on specific yield, ideally given site-specific for each monitoring well. However, this information is largely not available and difficult to estimate in areas with highly heterogeneous geology.

In our study we use a data set of groundwater level observations at about 3000 groundwater monitoring wells in France. Based on a high-resolution hydro-geological information system provided by the French geological survey (BRGM) and water authorities (BDLISA), we assign the borehole data to individual hydro-geological units. For the upscaling to river basin averages, we (i) aggregate the measurements that originate from the same unit and (ii) account for the areal fractions of the hydro-geological units within the river basin. For the interpretation of GW level variations to GW storage changes, we tested several approaches to estimate specific yield values for the individual hydro-geological units. Wherever possible, we use the specific yield values explicitly provided in the BDLISA data base, mostly estimated from pumping test analysis. When not available, we assign literature-based specific yield values based on the detailed lithological information provided for each unit. This method is compared to global porosity information provided by low resolution geological data from GHYLMPS (Gleeson et al., 2014)

Besides presenting the methodological approach, this presentation shows the resulting groundwater storage time series, averaged for individual river basins in France and for individual 0.5° grid cells. Additionally, comparisons to simulated groundwater storage variations of the WaterGAP Global Hydrology Model (WGHM) will be presented. We discuss the sensitivity of basin averaged GW storage time series to different choices of specific yield for individual boreholes.
The Samos earthquake event (Mw = 7, 30 October 2020, Greece) as case study for applying machine learning on texts and photos scraped from social networks for developing seismic intensity maps.
Authors: Arapostathis Stathis G
Published: March 2022

Main purpose of current research article is to present latest findings on automatic methods of manipulating social network data for developing seismic intensity maps. As case study the author selected the 2020 Samos earthquake event (Mw= 7, 30 October 2020, Greece). That earthquake event had significant consequences to the urban environment along with 2 deaths and 19 injuries. Initially an automatic approach, presented recently in the international literature was applied producing thus seismic intensity maps from tweets. Furthermore, some initial findings regarding the use of machine learning in various parts of the automatic methodology were presented along with potential of using photos posted in social networks. The data used were several thousands tweets and instagram posts.The results, provide vital findings in enriching data sources, data types, and effective rapid processing.
Storage, pools, and chemical composition of soil organic matter surplus due to tillage intensity drop
Authors: Jakab Gergely , Masoudi Malihe , Madarász Balázs , Filep Tibor , Zacháry Dóra , Karlik Máté , Dekemati Igor , Szalai Zoltán
Published: March 2022

Intensive tillage operations, especially moldboard plowing, are widely described as one of the leading causes of soil organic matter (SOM) decrease in cultivated topsoils. Experiments proved that afforestation or even dropped tillage intensity might increase the SOM content of the soil within decades. However, little is known about the forms and sequestration mechanisms of the recently produced organic matter under conservation agriculture practices. Thus, the present study aimed to test the following hypotheses on a Chernozem crop field shifted to conservation tillage: (i) SOM increase appears in the uppermost soil layer without any effect in the subsoil layer; (ii) SOM increase affects each (both labile and stabile) SOM pools of the soil; (iii) the increase modifies the SOM composition of the fractions. The investigations were carried out in a long-term field experiment established in 2002 at Józsefmajor, Hungary. The present study compares the SOM amount and composition of the 0-10 cm and 30-40 cm horizons under plowing, deep cultivation, and no-tillage. Decreasing cultivation intensity resulted in a general soil organic carbon (SOC) concentration increase in both the mineral phase associated OM (stable pool), and the aggregate occluded OM fractions (labile pool). This indicates a relevant saturation deficit in both fractions of the topsoil even though the particulate organic matter fraction did not change. The increase is probably due to the above-ground plant residue input surplus as the SOC content in the 30-40cm layer did not change. The SOM surplus stabilized in the soil did not affect SOM composition differences between depth and fractions resulted in a cultivation-independent chemical SOM composition. The only difference was aromaticity, which showed increasing stratification due to tillage intensity mitigation. These results suggest the highlighted role of dissolved organic matter movement in the profile as the possible driving force of differentiation of aromaticity with depth. The results also underline the role of local circumstances in organic matter composition changes, proving the process's complexity and the difficulties of holistic model construction. The present research was supported by the Hungarian National Research and Innovation Office (NKFIH) K-123953, which is kindly acknowledged.
Characterization of space-time structures in 3D simulations of plasma turbulence with Fast Iterative Filtering.
Authors: Papini Emanuele , Cicone Antonio , Piersanti Mirko , Franci Luca , Verdini Andrea , Montagud-Camps Victor , Hellinger Petr , Landi Simone
Published: March 2022

We present results from a multiscale spatiotemporal analysis of 3D Hall-MHD and hybrid kinetic numerical simulations of decaying plasma turbulence. By combining Fourier analysis and Fast Iterative Filtering, we compute the 3D k-ω power spectrum of the magnetic and velocity fluctuations at the time when turbulence has fully developed. We find that the magnetic fluctuations around and just below the ion characteristic scales mainly consist of strongly anisotropic perturbations, with temporal frequencies smaller than the ion-cyclotron frequency and with wave vectors almost perpendicular to the ambient magnetic field. Further analysis reveals that such perturbations cannot be described in terms of wave-like fluctuations, but rather consist of localized structures that are organized in a filamentary network of current sheets, which continuously form and disrupt as a consequence of magnetic reconnection, spontaneously induced by the interaction of turbulent structures. We discuss similarities and differences with respect to previous findings from 2D simulations, and we put our results in the context of spacecraft observations in the solar wind.
Transient small displacement since the end of 2020 at Noto peninsula, Japan, revealed by Sentinel-1 InSAR time series analysis
Authors: Kinoshita Yohei
Published: March 2022

At the end of 2020, anomalous transient surface deformation was observed by an operational GNSS network at the Noto peninsula, Japan. Although the Noto peninsula locates far from the plate boundary, seismic observations recorded that seismic swarms were accompanied with this transient deformation. Nishimura et al. (2021, presentation at the 2021 Geodetic Society of Japan) estimated that this deformation and swarms may be associated with the intrusion of water from the subducting oceanic plate. Here I performed Sentinel-1 InSAR time series analysis to obtain more detailed view of this transient displacement and to investigate the mechanism of this phenomenon.
In the analysis, at first I created interferograms from Sentinel-1 IW SLCs using ISCE2 software. Then these interferograms were used for the LiCSBAS time series analysis. Orbital and topographic fringes were modeled and removed based on precise orbit information and SRTM 1-arcsecond DEM. No atmospheric corrections were applied. I used both ascending and descending paths so that I could calculate 2.5 dimensional analysis to derive quasi-horizontal and quasi-vertical displacements.
The result of Sentinel-1 time series showed that the transient displacement seems to start since the end of 2020, which is consistent with the result from the GNSS observation. The estimated largest surface velocities became 13 mm/year in ascending and 15 mm/year in descending. The 2.5 dimensional analysis suggested that the uplift was concentrated at the eastern front of the peninsula, which is also consistent with the GNSS observation. The derived displacement fields suggested that there is an inflation source but this need to be further investigation by, for example, using elastic spherical and/or rectangular fault models.
By the presentation, I will perform the InSAR atmospheric correction and source modelling and show these results.
Parametrization of In Situ Cloud Particle Size Distributions Including Small Particles
Authors: Bartolome Garcia Irene , Sourdeval Odran , Krämer Martina , Spang Reinhold
Published: March 2022

The cloud particle size distribution (PSD) is a key parameter for the retrieval of microphysical and optical properties from remote sensing instruments, which in turn are necessary for determining the radiative effect of clouds. Current representations of PSDs for ice clouds rely on parameterizations that were largely based on in situ measurements where the distribution of small ice crystals (sizes smaller than 100 μm) were at best very uncertain. This makes current parameterisation inadequate to simulate remote sensing observations sensitive to small ice, such as from lidar or thermal infrared instruments.

In our study we fit the cloud particle size distributions (PSDs) of JULIA (JÜLich In situ Aircraft data set)*, **. This data set consists of 11 campaigns covering the tropics, mid-latitudes and the Arctic. For the fitting, we implement the method presented in the works of Field et al. (2005, 2007) and Delanoë et al. (2005, 2014) (referred as D05 and D14). The method consists on computing several moments of the measured in situ PSDs, use them to normalize the in situ PSDs and then fit the normalized PSDs to a certain function. Following D05 and D14, we use the normalization coefficients Dm (volume-weighted diameter) and N0* (intercept parameter) and a modified gamma function F(α, β, X). To find the right pair of α and β, first each in situ PSD is normalized using a random combination. Second, the observed ice water content (IWC) and number concentration (N) and the IWC and N obtained from the normalized PSDs are used to compute a cost function (J). The best α, β pair is the one that delivers the minimum value of J.  The main advantage of this work is that it provides a fitting including small particles, since the used data set covers sizes from 3 – 1000 μm

From this method, we provide an improved representation of PSDs that will be useable in retrievals schemes to estimate with greater accuracy ice cloud properties sensitive to the concentration of small ice crystals, such as N.

* see presentation of Krämer, M., Spelten, N., Afchine A. and Spang R.: Occurrence patterns of cloud particles sizes in cirrus and mixed-phase clouds; EGU 2022.

** see presentation of Spang, R., Spelten, N. and Krämer, M.: A database of microphysical and optical properties of thin to thick cirrus clouds derived from bimodal particle size distributions; EGU 2022.
Investigating the spatiotemporal relationship between thermal anomalies and surface deformation; The Arkalochori Earthquake sequence of September 2021, Crete, Greece.
Authors: Peleli Sofia , Kouli Maria , Vallianatos Filippos
Published: March 2022

Among the different parameters, the fluctuations of Earth's thermally emitted radiation, as measured by sensors on board of satellite systems operating in the Thermal Infra-Red (TIR) spectral range and Earth's surface deformation as recorded by satellite radar interferometry, have been proposed since long time as potential earthquake precursors. Nevertheless, the spatiotemporal relationship between the two different phenomena has been ignored till now.

On September 27, 2021, a strong earthquake of magnitude M5.8 occurred in Crete, near the village of Arkalochori at 06:17:21 UTC, as the result of shallow normal faulting. The epicenter of the seismic event was located at latitude 35.15 N and longitude 25.27 E, while the focal depth was 10 km. Since the beginning of June, almost 4 months earlier, more than 400 foreshocks ranging in magnitude from M0.5 to M4.8 were recorded in the broader area while the strongest aftershock (M 5.3) occurred on September 28th at 04:48:09 UTC.

10 years of MODIS Land Surface Temperature and Emissivity Daily L3 Global 1km satellite records were incorporated to the RETIRA index computation in order to detect and map probable pre-seismic and co-seismic thermal anomalies in the area of tectonic activation. At the same time, SAR images of the Sentinel-1 Copernicus satellite in both geometries of acquisition were used to create the differential interferograms and the displacement maps according to the Interferometric Synthetic Aperture Radar (InSAR) technique. Then, the two kinds of datasets (i.e thermal anomaly maps and crustal deformation maps) were introduced into a Geographic Information System environment along with geological formations, active faults, and earthquakes’ epicenters. By overlapping all the aforementioned data, their spatiotemporal relation is explored.
In-situ measurements of sediment temperature under shallow water bodies in Arctic environments
Authors: Miesner Frederieke , Cable William , Boike Julia , Overduin Pier Paul
Published: March 2022

The thermal regime under lakes, ponds, and shallow near shore zones in permafrost zones in the Arctic is predominantly determined by the temperature of the overlying water body throughout the year.   Where the temperatures of the water are warmer than the air, unfrozen zones within the permafrost, called taliks, can form below the water bodies.

However, the presence of bottom-fast ice can decrease the mean annual bed temperature in shallow water bodies and significantly slow down the thawing or even refreeze the lake or sea bed in winter. Small changes in water level have the potential to drastically alter the sub-bed thermal regime between permafrost-thawing and permafrost-forming. The temperature regime of lake sediments is a determining factor in the microbial activity that makes their taliks hot spots of methane gas emission. Measurements of the sediment temperature below shallow water bodies are scarce, and single temperature-chains in boreholes are not sufficient to map spatial variability.

We present a new device to measure in-situ temperature-depth profiles in saturated soils or sediments, adapting the functionality of classic Bullard-type heat flow probes to the special requirements of the Arctic. The measurement setup consists of 30 equally spaced (5cm) digital temperature sensors housed in a 1.5 m stainless steel lance. The lance is portable and can be pushed into the sediment by hand either from a wading position, a small boat or through a hole in the ice during the winter. Measurements are taken continuously and 15 minutes in the sediment are sufficient to acquire in-situ temperatures within the accuracy of the sensors (0.01K after calibration at 0°C). The spacing of the sensors yield a detailed temperature-depth-profile of the near-surface sediments, where small-scale changes in the bottom water changes dominate the temperature field of the sediment. The short time needed for a single measurement allows for fine-meshed surveys of the sediment in areas of interest, such as the transition zone from bottom-fast to free water.

 

Test campaigns in the Canadian Arctic and on Svalbard have proven  the device to be robust in a range of environments. We present data acquired during winter and summer, covering non-permafrost, thermokarst lake and offshore measurements.
Geodynamic Drivers of the East African Rift System
Authors: Glerum Anne , Brune Sascha , Ben Mansour Walid
Published: March 2022

The East African Rift System (EARS) is the largest active continental rift on Earth. Inherited lithospheric strength variations have played a large role in forming the system’s current geometry. The partly overlapping eastern and western EARS branches encompass the large Victoria continental microplate that rotates counter-clockwise with respect to Nubia, in striking contrast to its neighboring plates.

Both the forces driving rifting in the EARS as a whole and the rotation of Victoria in particular are debated. Whereas some studies largely ascribe the rifting to horizontal mantle tractions deriving from plume-induced flow patterns (e.g., Ghosh et al., 2013), or to more equal contributions of mantle tractions and gravitational potential energy (e.g., Kendall and Lithgow-Bertelloni, 2016), recent work by Rajaonarison et al. (2021) points to a dominant role for lithospheric buoyancy forces in the opening of the rift system. Similarly, other numerical modeling (Glerum et al., 2020) has shown that Victoria’s rotation can be induced through drag of the major plates along the edges of the microplate transmitted along stronger lithospheric zones, with weaker regions facilitating the rotation, without the need for plume-lithosphere interactions (e.g., Koptev et al., 2015; Calais et al., 2006).

With unprecedented data-driven, regional spherical geodynamic numerical models spanning the EARS and the upper 660 km of mantle, we aim to identify the individual contributions of lithosphere and mantle drivers of deformation in the EARS and of Victoria’s rotation. Observational data informs the model setup in terms of crustal and lithospheric thickness, sublithospheric mantle density structure and plate motions. Comparison to separate observations of the high-resolution model evolution of strain localization, melting conditions, horizontal stress directions, topography and horizontal plate motions allows us to identify the geodynamic drivers at play and quantify the contributions of large-scale upper mantle flow to the local deformation of the East African crust.

 

Calais et al. (2006). GSL Special Publications, 259(1), 9–22.

Ghosh et al. (2013). J. Geophys. Res. 118, 346–368.

Glerum et al. (2020). Nature Communications 11 (1), 2881.

Koptev et al. (2015). Nat. Geosci. 8, 388–392.

Rajaonarison et al. (2021). Geophys. Res. Letters, 48(6), 1–10.
Improving SAR Altimeter Processing over Inland Water - the ESA HYDROCOASTAL Project
Authors: Benveniste Jérôme , Cotton David ,   HYDROCOASTAL Project Team
Published: March 2022

Introduction

HYDROCOASTAL is a two-year project funded by ESA, with the objective to maximise exploitation of SAR and SARin altimeter measurements in the coastal zone and inland waters, by evaluating and implementing new approaches to process SAR and SARin data from CryoSat-2, and SAR altimeter data from Sentinel-3A and Sentinel-3B. Optical data from Sentinel-2 MSI and Sentinel-3 OLCI instruments will also be used in generating River Discharge products.

New SAR and SARin processing algorithms for the coastal zone and inland waters will be developed and implemented and evaluated through an initial Test Data Set for selected regions. From the results of this evaluation a processing scheme will be implemented to generate global coastal zone and river discharge data sets.

A series of case studies will assess these products in terms of their scientific impacts.

All the produced data sets will be available on request to external researchers, and full descriptions of the processing algorithms will be provided.

Objectives

The scientific objectives of HYDROCOASTAL are to enhance our understanding of interactions between the inland water and coastal zone, between the coastal zone and the open ocean, and the small scale processes that govern these interactions. Also, the project aims to improve our capability to characterize the variation at different time scales of inland water storage, exchanges with the ocean and the impact on regional sea-level changes.

The technical objectives are to develop and evaluate new SAR and SARin altimetry processing techniques in support of the scientific objectives, including stack processing, and filtering, and retracking. Also, an improved Wet Troposphere Correction will be developed and evaluated.

Presentation

The presentation will describe the different SAR altimeter processing algorithms that are being evaluated in the first phase of the project, and present results from the evaluation of the initial test data set. It will focus particularly on the performance of the new algorithms over inland water.
Regional variability in the thermal structure of Tibetan Lithosphere
Authors: Xia Bing , Artemieva Irina , Thybo Hans , Klemperer Simon
Published: March 2022

We present a thermal model- of lithospheric thickness and surface heat flow in Tibet and adjacent regions (74-110o E, 26-42o N) based on topography and seismic Moho. We interpret strong heterogeneity in lithospheric thermal structure to be caused by longitudinal variations in the northern extent of the subducting Indian plate, southward subduction of the Asian plate beneath central Tibet, and possible preservation of fragmented Tethyan paleo-slabs. Cratonic-type cold and thick lithosphere (200-240 km) with a predicted surface heat flow of 40-50 mW/m2 typifies the Tarim Craton, the northwest Yangtze Craton, and most of the Lhasa Block that is likely refrigerated by underthrusting Indian lithosphere. We identify a ‘North Tibet anomaly’ (at 84-92o E, 33-38o N) with thin (<80 km) lithosphere and high surface heat flow (>80-100 mW/m2) in a region with anomalous seismic Sn and Pn propagation. We interpret this anomaly as the result of removal of lithospheric mantle and asthenospheric upwelling at the junction of the Indian and Asian slabs with opposite subduction polarities. Other parts of Tibet typically have intermediate lithosphere thickness of 120-160 km and a surface heat flow of 45-60 mW/m2, with patchy anomalies in eastern Tibet.
Mineralogy of particles deposited on biomass and in soils from various smelter-polluted sites
Authors: Tuhý Marek , Ettler Vojtěch , Majzlan Juraj , Kiefer Stefan
Published: March 2022

For this investigation, biomass and soil samples from several smelter areas in sub-Saharan Africa were used. Grass samples and topsoils were collected in the Tsumeb area in northern Namibia (Cu-smelter, former mine), Selebi-Phikwe in Botswana (Ni-Cu mine and smelter), Luanshya in the Zambian Copperbelt (Cu mine and smelter), and Kabwe in central Zambia (Pb-Zn mine and smelter). Metal(loid)s concentration in soils and grass were generally in the order of hundreds to thousands mg/kg.

The surfaces of all the grass biomass samples contained a variety of geogenic (quartz, carbonates, clay minerals, feldspars) and anthropogenic (usually metal-bearing) particles directly attached to the biomass tissues. These smelter-derived particles are predominantly slag fragments enriched in various contaminants, droplets of metals/sulfides, and, in the case of the biomass from Kabwe, newly formed aggregates of submicrometric anglesite (PbSO4) crystals. Heavy mineral fractions were obtained from all biomass samples to better understand the solid-phase speciation of contaminants. In Tsumeb, the key metal-hosting minerals/phases on biomass were Cu-Fe sulfides, arsenolite (As2O3) and metal-bearing slag glass. In Selebi Phikwe pyrrhotite (Fe1-xS), pyrite (FeS2), pentlandite [(Fe,Ni)9S8] and chalcopyrite (CuFeS2) were predominant. Samples from Kabwe were composed of galena (PbS), pyrite (FeS2), sphalerite (ZnS), chalcopyrite (CuFeS2) and anglesite (PbSO4) and in Luanshya, the particulates were mainly formed by phases from the Cu-Fe-S ternary system. The mineralogy of particulates collected in the grass samples was similar to that in the corresponding topsoil samples. The knowledge of solid-phase speciation is of key importance for determining the fate of contamination in such environments.

This study was supported by the Czech Science Foundation (GAČR project no. 1-23794J) and a grant from the Endowment Fund of the Faculty of Science, Charles University, attributed to M. Tuhý. The Charles University team was partially supported by the institutional funding from the Center for Geosphere Dynamics (UNCE/SCI/006).
Investigating the influence of mesoscale dynamics and chemistry on urban air pollution 
Authors: du Preez David Jean , Knote Christoph
Published: March 2022

Urban air quality is the result of local emissions which are superimposed on variable regional and continental atmospheric conditions which are represented in mesoscale models. The complex urban microscale consists of interactions between wind and radiation patterns (street canyon wind systems, building shading and reflections), non-linear chemistry in the presence of strong local emitters, various reactive species and particles (biogenic VOC emissions, regional dust transport) as well the associated mesoscale meteorological dynamics.  

The components of both the mesoscale and microscale need to be accurately represented in any model system to understand their interactions and resulting air pollution effects. Here we investigate the interplay between the urban microscale and mesoscale phenomena using a dynamic coupling of the PALM and WRF-Chem models. We highlight the importance of the regional atmospheric conditions for air pollution events such as heatwaves and the associated ozone peaks, Saharan dust events and inversion situations which have detrimental effects on human health. 
Impact of the solar wind dynamic pressure on field-aligned currents in the magnetotail: Cluster observation 
Authors: Shi Jiankui , Cheng Zhengwei , Torkar Klaus , Dunlop Malcolm
Published: March 2022

The interaction of the solar wind with the Earth’s magnetosphere can result in various disturbance phenomena inside the magnetosphere, such as the density, occurrence, and distribution of the field-aligned currents (FACs) in the magnetosphere-ionosphere system. The FACs take an important role in the magnetosphere - ionosphere coupling and have been investigated for many decades. However, it’s response to the solar wind and IMF still needs to be further studied. In this study, we statistically investigate the influence of the solar wind dynamic pressure (SW Pdyn) on the FACs in the magnetotail based on 1492 FAC cases occurring from July to October in 2001 and 2004, which covers 117 Cluster spacecraft crossings of plasma sheet boundary layer (PSBL). The FAC density in the magnetotail is derived from the magnetic field data with the four-point measurement of Cluster and the SW Pdyn is derived from ACE data. It was confirmed that the magnetotail FAC density depended on the solar wind dynamic pressure during both magnetic storm and non-storm time, and the FAC density was much stronger with intense SW Pdyn during storm time. The statistical results show that the FAC occurrence increases monotonically with SW Pdyn in the three levels (weak: SW Pdyn<2 nPa; medium: 2 nPadyn<5 nPa; strong: SW Pdyn>5 nPa). The FAC density increases with increasing SW Pdyn, while its footprint (invariant latitude, ILAT) in the polar region decreases with increasing SW Pdyn. Also, the FAC in the magnetotail response to SW Pdyn has a north-south hemispheric asymmetry. The correlation of FAC density with SW Pdyn is better in the Northern Hemisphere, while the correlation of the footprint position with SW Pdyn is better in the Southern Hemisphere. Furthermore, the influences of the solar wind core angle and clock angle on the FAC density, occurrence, and distribution are also shown in this presentation. The concerned mechanisms for our results are analyzed and discussed.
Early Pleistocene route to Sangiran opened to Javanese Homo erectus
Authors: Husson Laurent , Lebatard Anne-Elisabeth , Zerathe Swann , Braucher Régis , Noerwidi Sofwan , Aribowo Sonny , Carcaillet Julien , Natawidjaja Danny Hilman , Bourlès Didier L. , Team Aster
Published: March 2022

The chronology of the arrival of Homo erectus on the island of Java is a cornerstone of paleoanthropology. Understanding the dispersal routes of Homo erectus, but also of other hominin lineages in Asia and across Southeast Asia, depends on this timing. Their dispersal across Sundaland, in particular, is challenged by an extremely transient climatic and geological environment during Early Pleistocene. Furthermore, ages of first appearance of Javanese H. erectus remain controversial. New age constraints based on cosmogenic nuclides 10Be and 26Al produced in situ indicate that H. erectus reached Java and dwelled at Sangiran at least ~1.4 Ma ago and more probably around 1.8 Ma. During this period, Java was just emerging from the sea while the adjacent Sundaland was a vast and continuous expanse of climatically and environmentally hospitable land connecting Java to mainland Asia, which facilitated the prior dispersal of hominins and terrestrial faunas to the edge of Java. This ancient age makes H. erectus the contemporary of the earliest members of the genus Homo in Africa and Asia, and rejuvenates the question of dispersal and evolutionary pathways across Eurasia and Sundaland.
Aerosol-Cloud-Turbulence Interaction in Multilayer Clouds Modeled on a Closed Trajectory between MOSAiC and MOSAiC-ACA
Authors: Chylik Jan , Kirbus Benjamin , Schnierstein Niklas , Wendisch Manfred , Neggers Roel
Published: March 2022

The transformation of cloudy air masses plays a key role in the ongoing Arctic Amplification. The complex system of the interactions between aerosols, cloud layers and turbulence is not yet fully understood, mostly due to broad range of scales involved and the lack of reliable in-situ measurements. 
We try to fill this gap by using a high resolution numerical simulation constrained with observations as a virtual laboratory. The focus of this study is the transformation of boundary layer mixed-phase clouds in the presence of higher cloud decks advected above them. The recent MOSAiC field campaign provided us with unique observations of developing cloudy air mass on a closed trajectory. The same air mass was sampled twice in September 2020, first by the research vessel Polarstern during the MOSAiC drift, and later by airborne instruments during the MOSAiC-ACA, its sister-campaign northwest of Svalbard.  We configured a high-resolution Lagrangian large-eddy simulation based on ERA5 reanalysis data and constrained it by in-situ measurements of the surface boundary condition, vertical thermodynamic structure and aerosol concentrations. The results of the simulations are then validated against independent cloud measurements. Our virtual laboratory also provides us opportunities to investigate the sensitivity of the transformation of the boundary layer clouds to the composition of the advected mid-tropospheric cloud decks. The importance of the seeder-feeder mechanism and radiative fluxes will be discussed, as well as further implications for the Arctic Amplification and future studies.
Tectonic control on the reef evolution in the Red Sea syn-rift basin
Authors: Pensa Tihana , Afifi Abdulkader , Delaunay Antoine , Baby Guillaume
Published: March 2022

Fossil carbonate reefs are common along rifts and rifted passive margins. They provide valuable paleoecological and paleogeographical information. Moreover, porous reef buildups are targeted as potential oil and gas reservoirs and sites for gas storage.

The Red Sea and Gulf of Suez contain several generations of reef deposits: (1) syn-rift Early and Middle Miocene reefs that formed along the eroded footwalls of normal faults, and (2) post-rift Pliocene-Holocene coastal reefs that split apart, subsided, and aggraded to form carbonate platforms by salt-driven raft tectonics. The Late Miocene lacks reefs due to evaporitic conditions. This study focuses on the uplifted Early-Middle Miocene reef deposits, which outcrop sporadically along the Arabian and African margins of the Red Sea, particularly the northern half, over a distance of ~1000 km. They are exhumed along the coastal plain at elevations of 50-150 meters. We studied several reefs on the Arabian side and carried out age determination implementing a revised planktonic foraminifera zonation and paleoenvironmental interpretation. We also used satellite images to identify and map similar exhumed reefs on the African side.

The Miocene reefs are located along the eroded footwalls of normal fault scarps that form the first or second marginal half grabens, usually sitting unconformably over the basement. The flat reef and back-reef lagoonal facies are often removed by erosion, but the dipping thick fore-reef talus breccias are preserved. The breccias are an unsorted mix of coral reef and back reef debris and also contain basement clasts. The linear fore-reef talus deposits follow along the fault scarps, revealing paleo-valleys incised into the hanging wall. Placing the reef on the basin-scale helps us distinguish the tectonic influence, accompanied by climate and eustatic sea-level variation, on shallow marine carbonates during rifting.

Mapping all published, newly discovered, and inferred outcrops along the African and Arabian coast of the Red Sea allow us to develop a new tectono-sedimentary model for reef evolution in the syn-rift setting. The proposed model explains the absence of the reef outcrops in the southern areas of the Arabian Red Sea and predicts subsurface zones where reef growth possibly took place. Nature of the contact between reef carbonates and the underlying Precambrian basement in conjunction with the consistently preserved fore-reef zone disclose the uplift history and erosion events prior and post reef growth. In addition, following the reef distribution, we developed a syn-rift paleogeographic model of the Red Sea.
Erosion and chemical weathering of siliceous rocks at the supply and kinetic limits
Authors: Bufe Aaron , Rugenstein Jeremy , Hovius Niels
Published: March 2022

The uplift and erosion of active mountain ranges and the consequent weathering of minerals modulates the global carbon cycle and impacts Earth’s climate on geologic timescales. However, the link between erosion and weathering is complex because weathering rates can be limited by the supply of minerals to the weathering zone, by the supply of acidic fluids, or by the kinetics of mineral weathering. Existing approaches that model the carbon cycle over geologic timescales assume that with increasing erosion rates, weathering transitions from a supply limit where weathering rates scale linearly with erosion to an ‘acid’ or a kinetic limit where weathering is insensitive to erosion. Alternative models fit a single power-law to the relationship between erosion and weathering across multiple orders of magnitude. The validity of these two approaches remains difficult to assess at the landscape scale because existing data do not cover all limits or because co-variation between runoff and erosion obscures the driver of changes in weathering rates. Here, we compile five datasets of solute concentrations in streams that span well-defined erosion rate gradients in relatively uniform lithologies and with limited or well-constrained variations in runoff. Across 2-3 orders of magnitude of erosion rates, and for both metasedimentary and granitic lithologies, we find that silicate weathering rates are insensitive to erosion rates. In turn, weathering of sulfide and carbonate minerals increase with erosion rates, consistent with a limitation by mineral supply. However, contrary to existing models of supply-limited weathering, we observe a non-linear increase of sulfide and carbonate weathering rates with erosion. These new findings suggests that supply-limited and kinetically limited zones of weathering co-exist within a single landscape across multiple orders of magnitude of erosion rate. The distribution of these zones is most likely controlled by erosion processes. As a consequence, existing weathering models that assume a linear relationship between erosion and weathering at the supply limit may overestimate the sensitivity of weathering rates to erosion and underestimate the impact of climate on these reactions, with implications for the effect of mountain building on the carbon cycle and on Earth’s climate.
Human-environmental interaction possibilities at the Neanderthals’ northern edge: focus on last interglacial and early last glacial
Authors: Nielsen Emil Schou , Nielsen Trine Kellberg , Kristiansen Søren Munch
Published: March 2022

Neanderthals are believed to have been adapted to cold climate conditions, nevertheless Neanderthal findings in the north and northeast European region are scares, non-existing or at least speculative. In between periods of arctic and subarctic conditions, warm periods like the Eemian interglacial would have offered mild living conditions in present-day southern Scandinavia and have evidently allowed migration of prey species to the region. We therefore suggest that the apparent absence of Neanderthals in the geological record here is partly steered by poor conditions of conservation, lack of in situ archives and lack of focused investigation, rather than a limit of the Neanderthal habitat per se. In this paper we seek to identify potential hotspots for Neanderthal activity in the geological record. We do this by mapping the paleolandscape from all available data sources and by 3D paleolandscape modelling, to identify potential Neanderthal living sites such as lake beaches, seashores and floodplains, where there would be easy access to water, prey and open habitat. Among the possible candidate sites, we will investigate by means of coring, whether the shores from Eemian lakes offer good conditions for preservation of potential find layers, as they might have a low degree of disturbance and in rare cases can offer in situ burial and conservation of interglacial fossils, archaeological material and sedimentary climate archives.
Advancing seismic processing of the Skaftá jökulhlaup in 2015, Iceland
Authors: Dietrich Thoralf , Eibl Eva P.S. , Binder Daniel , Lindner Fabian , Heimann Sebastian
Published: March 2022

Glacier lake outburst floods (GLOFs) are a recurring hazard in Alpine environments and can occur in orogenies with steep topography and short subglacial flood paths. In Iceland, the topography can be more flat and longer distances can be travelled below the ice. There, the locally named jökulhlaups can propagate tens of kilometers before emerging to the surface. It is difficult to monitor remote places, especially water movement below extensive icecaps. Permanent monitoring stations on ice are difficult to maintain. Off the ice, the networks are too sparse. By contrast, temporarily installed seismic arrays provide a tool to locate the flood front and issue early warnings of the subsequent flood of areas below the glacier. This is possible, as the flood-associated seismic signals migrate significantly during the event.

Seismic array analysis is in general a suitable method to locate weak, distant seismic events and observe floods. However, locations of long-lasting, emergent signals such as tremor are difficult to analyze. Due to the lack of clear onsets, travel time estimates are usually not possible. The location depends on other methods and the azimuthal station coverage. From 30 September to 3 October 2015, a flood drained from the eastern Skaftá cauldron in Iceland, reaching a peak discharge of 3000 m3/s in the Skaftá river. The seismic data were analysed using classical fk-analysis (Eibl et al. 2020). Here we advance the seismic processing including Pyrocko-based modules cake and parstack, and matched-field processing that allows to mute for example dominant noise sources. This helps to address the following questions: Can we detect signals of the flood along the uppermost part of the flood path? Can we detect the seismic signal during the subglacial flood propagation on an array which is dominated by river noise? Can we enhance the characteristics when correlating in the time domain? Our goal is to refine the location of the seismic tremor to enhance our understanding on the tremor generation and flood propagation, but also to test whether the analysis is stable enough to apply it to other floods of similar systems e.g. Grimsvötn.