bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of the persistent aromatic carbon content in biochar
Authors: Voßwinkel Silvio , Ulbricht Axel , Hagemann Nikolas , Schmidt Hans-Peter , Herdegen Volker , Braeuer Andreas Siegfried
Published: February 2023

Quantification of the time-dependent carbon sequestration by biochar remains a challenge. Recently, hydrogen pyrolysis was suggested to identify the content of stable polycyclic aromatic carbon (SPAC) or persistent aromatic carbon (PAC), which would not degrade to a relevant extent for centennial timescales due to their high degree of aromaticity and condensation (>7 rings). However, hydrogen pyrolysis is too expensive and laborious for broad application or even use in routine analysis.Here, we test a suite of analytical methods in order to identify alternatives to hydrogen pyrolysis for the quantification of SPAC/PAC in routine analysis of biochar or other pyrogenic carbons. We use 34 experimental biochars out of two precursors, wood and straw, produced at different highest treatment temperatures (HTT = 400-800 °C) and eight industrial biochars obtained from different feedstocks and different pyrolysis technology with HTT of 550-1200 °C. The methods include elemental analysis to obtain molar ratios of H/C and O/C, electrical conductivity of the solid as a proxy for the degree of condensation, thermogravimetric analysis coupled to differential scanning calorimetry (TG-DSC) to assess thermal stability (R50) and Raman spectroscopy. Raman spectra of the D- & G band provide information on the nanostructural development and should allow relative quantification of the semi-persistent and persistent carbon fractions. An incubation experiment (biochar + sand + compost microbial consortium) under laboratory conditions will provide direct data on biochar mineralization to quantify the semi-persistent fraction (SPC).Using a broad range of HTT and two different precursors as well as industrial biochars out of existing commercial pyrolysis reactors, we aim to cover a relevant parameter space to identify the possible range of SPAC/PAC and SPC content in industrial biochars. In an ideal case, this work will enable the use of low-cost technology such as Raman and/or electrical conductivity of the solid to quantify or estimate SPAC/PAC with a sufficient accuracy and precision.
Analysis of root distribution and its effect on soil respiration using Hydrus
Authors: Puthussseri Valiyaveettil Asha Nambiar , de Rooij Gerrit Huibert
Published: February 2023

It is not yet certain if temperate forests are net sources or sinks for atmospheric carbon, making it difficult to assess their potential role in mitigating climate change.  Root distribution and root growth in forests are important for soil respiration in forest soils, which in turn is one of the factors that determine carbon sequestration in and release from these soils. The aim of this study is to examine the effect of rooting depth and root distribution on soil respiration in different types of forest in north-eastern Germany through simulations with the Hydrus-1D model. The model combines a solver for Richards’ equation for soil water flow with routines that determine incorporation of carbon in the soil biomass as well as CO2 production by through respiration and decay. A  simple root distribution function with a single parameter will be used to model the root distribution. The presentation will report the first results of the study. 
Evaluating nudged coupled climate models against MOSAiC observations reveals weaknesses in the representation of clouds, boundary-layer turbulence and snow pack
Authors: Pithan Felix , Athanase Marylou , Dahlke Sandro , Sánchez-Benítez Antonio , Shupe Matthew , Sledd Anne , Streffing Jan , Svensson Gunilla , Jung Thomas
Published: February 2023

Comparing the output of general circulation models to observations is essential for assessing and improving the quality of models. While numerical weather prediction models are routinely assessed against a large array of observations, comparing climate models and observations usually requires long time series to build robust statistics.
Here, we show that by nudging the large-scale atmospheric circulation in coupled climate models, model output can be compared to local observations for individual days. We illustrate this for three climate models during a period in April 2020 when a warm air intrusion reached the MOSAiC expedition in the central Arctic. Radiosondes, cloud remote sensing and surface flux observations from the MOSAiC expedition serve as reference observations. The climate models AWI-CM1/ECHAM and AWI-CM3/IFS miss the diurnal cycle of surface temperature in spring, likely because both models assume the snow pack on ice to have a uniform temperature. CAM6, a model that uses three layers to represent snow temperature, represents the diurnal cycle more realistically. During a cold and dry period with pervasive thin mixed-phase clouds, AWI-CM1/ECHAM only produces partial cloud cover and overestimates downwelling shortwave radiation at the surface. AWI-CM3/IFS produces a closed cloud cover but misses cloud liquid water. All models overestimate downward turbulent heat fluxes under stable stratification, a long-standing issue in weather and climate models.
Our results show that nudging the large-scale circulation to the observed state allows a meaningful comparison of climate model output even to short-term observational campaigns. We suggest that nudging can simplify and accelerate the pathway from observations to climate model improvements and substantially extends the range of observations suitable for model evaluation.
The early to mid-Pliocene latitudinal migration of the Southern Ocean subtropical front (IODP Site U1475, Agulhas Plateau)
Authors: Tangunan Deborah , Hall Ian , Beaufort Luc , Berke Melissa , LeVay Leah , Mejia Luz Maria , Palike Heiko , Starr Aidan , Flores Jose Abel
Published: February 2023

The latitudinal migration of the Southern Ocean hydrographic fronts has been suggested to influence oceanographic conditions within the Indian-Atlantic Ocean gateway by restricting the amount of warm, saline water from the Indo-Pacific, transported by Agulhas Current, feeding into the South Atlantic via the Agulhas leakage. The Agulhas Current is an integral part of the global thermohaline circulation system as it acts as potential modulator of the Atlantic Meridional Overturning Circulation, which drives changes in regional and global climate, over at least the last 1.4 million years. However, the dynamics of this frontal system and associated changes in surface ocean biogeochemistry have not been explored beyond this time period due to absence of long continuous records spanning the Pliocene. Using International Ocean Discovery Program Site U1475 located on the southwestern flank of the Agulhas Plateau (41°25.61′S; 25°15.64′E; 2669 m water depth), we present high-resolution palaeoclimate records spanning the early to mid-Pliocene (~2.8 to ~5 Ma), from assemblage composition and morphometry of coccoliths, combined with oxygen and carbon stable isotopes from the bulk coccolith fraction. Our new Pliocene reconstructions offer evidence of the changing position of the subtropical front in the Southern Indian Ocean, driving variations in surface ocean conditions (e.g., nutrients, temperature, stratification), and thus biological productivity. We also explore expressions of coccolith δ13C vital effects from size-separated coccolith fractions together with planktic foraminifer carbon and oxygen stable isotopes from co-registered samples, that have been linked to cell size, growth rate, and calcification degree, providing empirical correlation with aqueous and atmospheric CO2 concentrations.
A statistical approach on rapid estimations of climate change indices by monthly instead of daily data
Authors: Hasel Kristofer , Bügelmayer-Blaschek Marianne , Formayer Herbert
Published: February 2023

Climate change indices (CCI) defined by the expert team on climate change detection and indices (ETCCDI) profoundly contribute to understanding climate and its change. They are used to present climate change in an easy to understand and tangible way, thus facilitating climate communication. Many of the indices are peak over threshold indices needing daily and, if necessary, bias corrected data to be calculated from. We present a method to rapidly estimate specific CCI from monthly data instead of daily while also performing a simple bias correction as well as a localisation (downscaling). Therefore, we used the ERA5 Land data with a spatial resolution of 0.1° supplemented by a CMIP6 ssp5-8.5 climate projection to derive different regression functions which allow a rapid estimation by monthly data. Using a climate projection as a supplement in training the regression functions allows an application not only on historical periods but also on future periods such as those provided by climate projections. Nevertheless, the presented method can be adapted to any data set, allowing an even higher spatial resolution.
The role of propagating signals in the gyre-scale interannual to decadal sea level variability in the subpolar North Atlantic
Authors: Volkov Denis , Schmid Claudia , Chomiak Leah , Germineaud Cyril , Dong Shenfu , Goes Marlos
Published: February 2023

The gyre-scale, dynamic sea surface height (SSH) variability signifies the spatial redistribution of heat and freshwater in the ocean, influencing the ocean circulation, weather, climate, sea level, and ecosystems. It is known that the first empirical orthogonal function (EOF) mode of the interannual SSH variability in the North Atlantic exhibits a tripole gyre pattern, with the subtropical gyre varying out of phase with both the subpolar gyre and the tropics, influenced by the low-frequency North Atlantic Oscillation. We show that the first EOF mode explains the majority (60 %–90 %) of the interannual SSH variance in the Labrador and Irminger Sea, whereas the second EOF mode is more influential in the northeastern part of the subpolar North Atlantic (SPNA), explaining up to 60 %–80% of the regional interannual SSH variability. We find that the two leading modes do not represent physically independent phenomena. On the contrary, they evolve as a quadrature pair associated with a propagation of SSH anomalies from the eastern to the western SPNA. This is confirmed by the complex EOF analysis, which can detect propagating (as opposed to stationary) signals. The analysis shows that it takes about 2 years for sea level signals to propagate from the Iceland Basin to the Labrador Sea, and it takes 7–10 years for the entire cycle of the North Atlantic SSH tripole to complete. We demonstrate that the observed interannual-to-decadal variability of SSH, including the westward propagation of SSH anomalies, is the result of a complex interplay between the local wind and surface buoyancy forcing, and the advection of properties by mean ocean currents. The relative contribution of each forcing term to the variability is space and time dependent. We show that the most recent cooling and freshening observed in the SPNA since about 2010 were mostly driven by advection associated with the North Atlantic Current. The results of this study indicate that signal propagation is an important component of the North Atlantic SSH tripole, as it applies to the SPNA. 
An integrative spatial approach to reducing risk posed by heat and heavy rainfall for the growing polycentric region of Stuttgart
Authors: McMillan Joanna , Göttsche Franziska
Published: February 2023

For the Stuttgart region, as a polycentric, highly dense area with strong economic growth, adapting to the effects of climate change is a key prerequisite for maintaining the quality of life and living in the region’s 179 towns and communities, as well as the security and competitiveness of the region as a whole. The region is already characterized by serious summer heat stress and air quality problems. Heavy rain events, such as the one most recently in July 2021, have repeatedly hit important infrastructure facilities. Adapting to such events and their impact is a priority for the region, as is creating more housing for the growing population and space for the growing economy. In order to avoid conflicts between these and other goals, an integrative strategic spatial planning approach at the city-regional level is required. This not requires up-to-date information on the probability and spatial distribution of heat stress and heavy rain events and spatially differentiated information on the vulnerability of society and the physical urban and regional structures. In order to reduce damage from extreme precipitation events and reduce the health effects of heat stress, regional and local planners need to know where the greatest need for adaptation lies while considering future processes of social change and changes in land use. Reliable methods for surveying and spatially representing vulnerabilities and adaptation needs and for integrating this with information about climate hazards and physical structures are lacking. In this talk, we illustrate this problem using the example of the Stuttgart region. We present an approach to record and evaluate the current and future vulnerability in the Stuttgart region using socio-economic and settlement-structural parameters.
Modeling the age of subsurface runoff at the catchment scale – what makes it younger or older?
Authors: Heidbüchel Ingo , Yang Jie , Fleckenstein Jan H.
Published: February 2023

Whether subsurface flow is relatively young or old when it passes by the catchment outlet is a strong indicator of weathering processes, nutrient availability, pollution susceptibility and the hydrologic response of a catchment. It depends not only on individual catchment, climate, event and vegetation properties, it is also the result of a multitude of interactions between different processes and catchment states within the hydrologic system.In order to begin to disentangle the cause-effect chains (or better even: webs), we employed the physically-based, spatially explicit 3D model HydroGeoSphere in a virtual catchment running 100 scenarios with different combinations of catchment, climate and vegetation properties. One result showed, e.g., that streamflow in forested areas appeared to become older on average compared to a non-vegetated site. Upon closer inspection, this was not necessarily only caused by subsurface runoff becoming slower/older due to lower hydraulic conductivities of drier soils when there was active root water uptake. Another component of this increase in stream water age was the different partitioning of precipitation into subsurface runoff and groundwater flow. Relatively more water was transported in the slower groundwater domain and less within the soil at the bedrock-soil interface.This is to show that, in order to make meaningful predictions about the age of hydrologic fluxes, it may not be the best approach to single out specific catchment and climate properties. Instead, it can be extremely helpful to look at the individual properties and the processes they control, their potential interactions and interdependencies, in a bottom-up approach within the framework of a hydrologic model.
Unmanned Aerial Vehicles for the Joint Aeolus Tropical Atlantic Campaign
Authors: Marenco Franco , Kezoudi Maria , Papetta Alkistis , Keleshis Christos , Ryder Claire , Ratcliffe Natalie , Kandler Konrad , Girdwood Joe , Stopford Chris , Wienhold Frank , Gao Ru-Shan , Marinou Eleni , Amiridis Vassilis , Baars Holger , Mocnik Grisa , Sciare Jean
Published: February 2023

During June 2022, the Cyprus Institute (CyI) took part in the ASKOS experiment in Mindelo, Cape Verde, with several of Unmanned Aerial Vehicles (UAVs), fitted with a number of in-situ aerosol instruments able to profile the Saharan Air Layer between the surface and an altitude of 5,300 m. In addition to ASKOS objectives, transnational access project Diurnal vAriation of the vertically resolved siZe distribution in the Saharan Air Layer  (DAZSAL) was also carried out at the same time. The campaign aimed at validating the Aeolus L2A product in the presence of dust and marine aerosols, estimating the influence on Aeolus products of non-spherical particles, evaluating the impact of particle orientation, and study the diurnal cycle of the dust size-distribution at high altitude. In this presentation we will present and discuss the scientific objectives, the context, the Unmanned Aerial Systems (UASs) that we developed in-house, and the instruments used, together with their limitations, calibration methods, uncertainties, challenges and difficulties encountered. We will also discuss the logistical and planning challenges that such a campaign entails.Operations took place from the Cesaria Evora International Airport. The instruments deployed on-board the UAVs permitted to evaluate the height-resolved particle size-distribution between 0.1 and 40 µm and detect cases of particle orientation, to complement the observations with ground-based remote sensing set out by NOA and TROPOS. Moreover, 24 high-altitude dust samples were collected on impactors, for further analysis by Scanning Electron Microscopy. In total, 25 scientific flights were performed on 12 flying days (almost half of which at night). Five flights were conducted during Aeolus overpasses. Weather has been a determining factor for both the ground-based remote sensing operations and the UAS operation, and airport traffic has been another constraint that needed to be accounted for, in the UAS operation.
Spatiotemporal Characteristics of Tropical Cyclone Induced Remote Moisture Transport affecting East Asia using Digraphs
Authors: Xiao Shiqi , Zhang Aoqi , Chen Yilun , Li Weibiao
Published: February 2023

Attention of tropical cyclone (TC) induced remote moisture transport has increased over the past several decades. There is significant progress of objective identification to resolve spatiotemporal merging and spitting of the moisture transport patterns using digraphs to represent clusters inside the patterns. This identification method also reflects discontinuous and uneven moisture transport. However, finding the mainstreams of these patterns still remains a challenge, which is necessary to retrieve statistical and geometric features of these patterns. To solve this issue, we assign the weight that is positive and decreases with increasing cross-border moisture transport between two clusters corresponding to two nodes to their edges to process the strongest connected component and dijkstra shortest path algorithms to find the main stream of moisture transport pathways. The frequency of TC remote transport is the highest in July over North China and Korean Peninsula and in September over South China and northern Vietnam. The statistical and geometric features of TC remote moisture transport are analyzed in the key periods and regions above. Moreover, discontinuity of moisture transport over the key periods and regions is quantified by the temporal variability of weights over the lifecycles of moisture transport patterns. Unevenness of moisture transport is quantified by the spatial variability of length of the mainstream. Vertical cross section of physical decomposition of moisture transport along the mainstream is further analyzed in this study.
The role of REddyProc's friction velocity filter in determining the carbon budget of croplands
Authors: Ingwersen Joachim , Poyda Arne , Kremer Pascal , Streck Thilo
Published: February 2023

In Poyda et al. (2019), we determined the carbon balance of six cropland sites in Southwest Germany on the basis of half-hourly net ecosystem exchange (NEE) fluxes measured with the eddy covariance (EC) method over a period of eight years from 2010 to 2017. We came up with the finding, that the sites lost on average about one ton of carbon per hectare and year. This huge loss was surprising, because the sites have been used as croplands already over several decades, and one would expect that the sites should be close to steady-state. In April 2022, we performed a soil organic carbon inventory at one of the six sites, and compared it with carbon data collected in April 2009. The soil inventory data do not give any evidence for a carbon loss in the order of one ton of carbon per hectare and year. Based on the data collected in April 2009, the carbon stock size of the plowing horizon at that time was 39.1 t C ha-1 yr-1. The carbon stock size determined in April 2022 was in the same range and amounted 39.9 t C ha-1 yr-1 with a standard error of 1.9 t C ha-1 yr-1, what means that these data indicate that the carbon budget of the cropland is indeed in or close to steady-state. In Poyda et al. (2019), the NEE flux data were gap-filled with the widely used software tool REddyProc. In REddyProc, the user has the option to apply or not to apply the friction velocity  (u*) filter before gap-filling. In Poyda et al. (2019), the u* filter was applied before gap-filling. We reprocessed the data for the year 2016, the only year with no winter time gaps, because a methanol fuel cell supplied the station with additional power, without applying the u* filter. Without applying the u* filter the cumulated annual NEE was ‑2080 kg C ha-1. Applying the u* filter increased the NEE by 836 kg C ha-1 to -1244 kg C ha-1. We did the same comparison for NEE fluxes measured at the same site over the years 2019, 2020 and 2021, and we got a similar result. The application of the u* filter increased the mean NEE by +730 kg C ha-1. The cumulated NEE was -2832 kg C ha-1 without u* filter and -2102 kg C ha-1 with u* filter. This positive bias is in the range of the EC based derived carbon loss and is able to explain a major part of the suspected positive bias. We recommend all REddyProc users to check their NEE data for this phenomena simply by processing the data once with and once without enabling the u* filter and comparing both results.
Glaciations of the East Siberian Sea
Authors: Amantov Aleksey , Amantova Marina , Cathles Lawrence , Fjeldskaar Willy
Published: February 2023

The existence and nature of Quaternary glaciations of the eastern part of the Arctic basin is very far from being solved, and many think glaciations there may been absent or very local, even at the Last Glacial Maximum.  It is unlikely under the conditions of permafrost and low precipitation during MIS 2, that the glaciers would have produced significant topographic relief.  However, significant ice loads will produce a significant isostatic response.  In the area of the Novosibirsk Islands, Holocene changes in sea level and transitions from continental to marine sedimentation indicate differences in emergence over the course of the transgression  that suggest the melting of significant grounded ice masses (e.g. Anisimov et al., 2009). Shorelines deviate from those expected from the hydroisostatic component. The best-fit isostatic model suggests significant LGM ice accumulation close to the ocean in the area of the Henrietta and Jeannette islands of the De Long archipelago in the East Siberian Sea. The uplift deviations in the Zhokhov island district are best matched for an effective elastic lithosphere thickness Te ~40 km. The ice accumulations close to the shelf-ocean margin in the last glaciation seem to also have occurred in earlier glaciations of the region.
Anisimov, M.A., Ivanova, V.V., Pushina, Z.V., Pitulko, V.V. 2009. Lagoon deposits of Zhokhov Island: age, conditions of formation and significance for paleogeographic reconstructions of the Novosibirsk Islands region // Izvestiya RAS, Geographical Series. No. 5. pp. 107-119.
Changes in regional and simultaneous soybean losses in the Americas due to projected global warming
Authors: Moreno Dumont Goulart Henrique , van der Wiel Karin , Folberth Christian , Boere Esther , van den Hurk Bart
Published: February 2023

Soybeans are globally used as the main source of protein for livestock. However, most soybean production is concentrated in regions in The United States of America, Brazil and Argentina, rendering the supply chain vulnerable to regional disruptions. In 2012, simultaneous soybean losses in these three countries led to shortages in global supplies and to record prices. The losses were linked to anomalous weather conditions in all three countries. In this experiment, we investigate how climate change may affect future events with similar or larger impacts than the one from 2012 for each country individually and simultaneously. For that, we develop a hybrid model, coupling a process-based crop model with a machine learning model, to improve the simulation of soybean production. We assess the frequency and magnitude of events with similar or larger impacts than 2012 under different future climatic forcing conditions. We also evaluate the events with respect to present day and future conditions to disentangle the impacts of (changing) climate variability from the long-term mean trends. Results indicate that long-term trends of mean climate increase the occurrence and magnitude of 2012 analogue crop yield losses. Conversely, 2012 analogue crop yield losses that are caused by changes in climate variability show an increase in frequency in each country individually, but not simultaneously across the Americas.
ELF-transients detected in the broadband recordings at the Hylaty station in Poland
Authors: Bozoki Tamas , Młynarczyk Janusz , Bor Jozsef , Kubisz Jerzy , Bozso Istvan , Horvath Andras , Kuslits Lukacs , Timko Mate
Published: February 2023

Lightning acts as a natural antenna radiating electromagnetic (EM) waves in a wide frequency range. In the extremely low frequency (ELF) band (3 Hz - 3 kHz), lightning-induced EM waves suffer very weak attenuation while they propagate in the waveguide formed by the Earth’s surface and the lowest part of the ionosphere. These EM waves can travel around the Earth several times before losing most of their energy. This allows ELF-transients generated by powerful lightning discharges from around the globe to be detected at any observation site. We developed an algorithm that identifies ELF-transients in the broadband recordings at Hylaty, Poland (sampling frequency: 3004.81 Hz, antenna bandwidth: 0.02 Hz to 1.1 kHz) and finds their most probable source lightning discharge in the lightning database of the Word Wide Lightning Location Network (WWLLN) based on the technique described by Bór et al. (2022).Between July 2020 and April 2021 about 270,000 ELF-transients were found in the records from Hylaty. The most probable source of 160,000 transients  was identified in the WWLLN database. Using this data set, we show that the propagation speed of broadband ELF-transients differ significantly when the propagation path is on the dayside or on the nightside of the Earth. It is also demonstrated that for lightning discharges close to Hylaty (d<2Mm), the timing and location accuracy of WWLLN has a large impact on the identification of the lightning source and on the inferred propagation speed. A convolutional neural network, trained with ELF-transients of known source location, was used to determine the distance to the lightning source in cases where the source lightning discharge could not be found in the WWLLN database. The average accuracy of the distance provided by the neural network is 700 km. No significant difference can be seen between the distribution of distances obtained by matching the source lightning stroke in the WWLLN database and that obtained using the neural network-based approach. Reference:Bór, J., Szabóné André, K., Bozóki, T., Mlynarczyk, J., Steinbach, P., Novák, A., and Lemperger, I. (2022): Estimating the Attenuation of ELF-Band Radio Waves in the Earth’s Crust by Q-Bursts. IEEE Transactions on Antennas and Propagation, 70, 8. https://doi.org/10.1109/TAP.2022.3161504
Greenhouse gas (CO2, N2O, CH4) fluxes from intensively managed grassland during a N2O mitigation experiment
Authors: Feigenwinter Iris , Hörtnagl Lukas Johannes , Buchmann Nina
Published: February 2023

Agriculture is the main contributor to anthropogenic emissions of nitrous oxide (N2O) and methane (CH4). Greenhouse gas (GHG) mitigation options in agricultural ecosystems are therefore urgently needed. In contrast to carbon dioxide (CO2), continuous measurements of N2O and CH4 fluxes are still scarce. In this study, we investigated management and environmental drivers of N2O and CH4 fluxes, which were measured using eddy covariance in a predominantly mown temperate grassland. A N2O mitigation experiment took place at the site where two parcels surrounding the eddy station were managed differently: at the experimental parcel, organic fertilizer was replaced by an increased legume (clover) proportion while the other parcel was still fertilized with slurry. Random forest gap-filling models were able to capture intermittent emission peaks well, with a better performance for half-hourly N2O than for CH4 fluxes. The unfertilized clover parcel showed reduced N2O emissions (4.4 and 2.7 kg N2O-N ha-1 yr-1) compared to the fertilized parcel (6.9 and 5.9 kg N2O-N ha-1yr-1) over two years, which confirmed the results from the first years of the experiment. The net ecosystem CO2 exchange (NEE) showed high interannual variability, which had a substantial influence on the grassland GHG budget. Overall, reducing fertilization and increasing the legume proportion were effective N2O reduction measures. N2O and CH4 fluxes play an important role in the GHG budget of agricultural ecosystems as they can partly offset the ecosystem CO2 uptake.
Ocean surface wave measurements from a phase array high-frequency radar system in the coastal area of Northwest of Mexico Pacific waters
Authors: Guevara Aguirre Juan Carlos , Durazo Reginaldo , García-Nava Héctor , Esquivel-Trava Bernardo , Gomez Roberto , Ocampo-Torres Francisco J.
Published: February 2023

High frequency radars (HFR) are systems that allow us to monitor some oceanographic variables through the backscatter signal from the ocean surface.  Typically, they provide us with a relatively high space-time resolution of surface currents and the wave field, very important local information to be used for maritime operation applications, such as search and rescue, safety at sea and transportation, and marine energy resources assessment.  Although the main product from HFR is ocean surface currents, they can in addition, provide useful information to derive important characteristics of the wave field, such as significant wave height (Hs) and even the directional spectrum. We, nevertheless, focus our attention in this work in the wave field, and specifically Hs values. A HFR (WERA system) is in operation in Todos Santos Bay, Ensenada, Mexico, since March 2021. Maps of significant wave height are estimated every hour over an area of approximately 250 km2 with spatial resolution of 800 m. These measurements have been compared with wave data derived from three moored instruments (ADCP), the results yielded correlations greater than 0.7 and RMSE values less than 40 cm. In the last two decades this technology has been implemented throughout the world, although there is very limited detail on calibration and validation of the instrument with local ocean wave conditions, especially with respect to the presence of swell. In this study, an empirical calibration is performed using an algorithm provided by the manufacturer in which a correction parameter  is obtained according to the operating frequency of the radar, in particular a WERA system. This study takes into consideration some particular characteristics of the area of interest and the performance of the correction parameter is determined as a function of the wave height and direction of travel relative to the radial direction from the WERA site.
Forest conversion cuts off biogeochemical connections of the subsoil to the top
Authors: Kilian Salas Simone , Andrino Alberto , Díaz García Elisa , Boy Diana , Horn Marcus A. , Boy Jens , Guggenberger Georg , Jungkunst Hermann F.
Published: February 2023

Losses in above- and belowground biodiversity are linked to changes in land use practices and immediately affect processes in the upper soil horizons. Theoretically, these superficial changes are reversible unless a tipping point on an ecosystem level was crossed. This safety net of functional redundancy facilitates the return of vital soil functions and processes to the initial state. Little is known about how deep these changes have reached into the subsoil over time, because early warning indicators of a tipping point being about to be crossed are still sparse. This is especially important for the tropics, as soils are typically intensively weathered and nutrient depleted, therefore, plants relying largely on nutrients from below. Net nitrous oxide (N2O) emission rates from the soil surface have proved to be valid proxies for detecting the crossing of tipping points in soil biogeochemistry. Here, we advanced this approach by looking deeply into the soil and reveal that potential greenhouse gas (GHG) production and consumption are useful proxies to estimate how deep the loss of aboveground biodiversity has already impacted soil microbial processes. We performed incubation experiments on forest and pasture soils stemming from shallow as well as 1 m deep profiles from the Peruvian Amazon Basin to determine the production and consumption potential of the GHGs at different water holding capacities. We expected pasture soils to have lost direct carbon(C)-related connections to deeper soil horizons. In forests, roots with different and greater depths also connect deeper soil layers. Therefore, in greater depth, carbon dioxide (CO2) production declined faster under pastures than under forests because C limitations are reached sooner. In the surface, grasses are well known for their input of C and increased CO2 production. Since old pastures are limited in nitrogen (N), almost no N2O should be produced, possibly increasing the potential to take up N2O. However, denitrification is a heterotrophic process also dependent on available C, therefore, the potentials of N2O production and consumption in deeper forest soils were larger with increasing water holding capacity. These findings could indicate that losses in aboveground biodiversity due to forest conversion can have profound impacts on soil microbial processes, extending also to deeper soil layers while altering the connection of the subsoil to the top.
GPR and Ultrasonic investigations to study the degradation of the Auriga statue (Mozia island, Sicily)
Authors: Capizzi Patrizia , Martorana Raffaele , Carollo Alessandra , Canzonieri Alessandro
Published: February 2023

The archaeological museum of the Giuseppe Whitaker Foundation (Mozia island, Sicily), exhibits the Greek statue of the Auriga, which has been the subject of geophysical investigations to evaluate the degradation of the marble. In particular, a 3D ultrasonic tomography (UST) and some georadar investigations were performed. For the UST 114 measurement points were used, selected on the surface of the statue. The results of the US tomography show an average velocity of the marble equal to about 4700 m/s, which indicates a good mechanical resistance of the marble. There are widespread areas with lower velocity (around 3000 m/s), which however fall within the range of variability of the material. A comparison was made with ultrasound data acquired in January 2012, during a previous diagnostic campaign. Georadar profiles were performed to highlight any internal discontinuity surfaces, which can be interpreted with the presence of fractures and/or lesions. In all the georadar profiles acquired, the internal signal of the material shows a general homogeneity, which allows to exclude the presence of fracturing surfaces and/or internal lesions.
Glacier Surges Past and Present: Theory, Current Distribution and the Landform Record
Authors: Benn Douglas
Published: February 2023

The oft-quoted statistic that 1% of the world’s glaciers are surge-type may suggest that surging is a rare, anomalous phenomenon. Among some populations of glaciers, however, surge-type glaciers are in the majority. For example, for glaciers over 16 km in length in Svalbard and Iceland over half have recorded surges. Surge-type glaciers are widespread in a broad arc stretching from Alaska to Novaya Zemlya (the Arctic Ring) and in many parts of High Mountain Asia. This distribution is defined by ranges of temperature and precipitation within which many glaciers cannot achieve stable steady states, as predicted by Enthalpy Balance Theory. Climatic controls on surging behaviour imply that the distribution of surge-type glaciers will shift in response to changes in temperature and/or precipitation. For example, the Arctic Ring may have been located south of its current position during some colder periods of the Quaternary. This was likely the case for Younger Dryas glaciers in Scotland. Reconstructions of palaeotemperature and palaeoprecipitation indicate that the Highlands and Islands of Scotland fell within the optimal climatic envelope for surging during the Younger Dryas. Examination of the landform record supports the conjecture that surge-type glaciers were widespread, including many outlet glaciers of the West Highland Icefield and smaller icecaps on the islands. Recognition of palaeosurges is important, because glacier reconstructions are commonly used as climatic proxies based on the assumption that glacier geometries represent stable steady states. Landsystem models are useful in this regard, provided they are applied flexibly with due consideration for local conditions and preservation biases. Systematic use of landsystem models and other tools may reveal other former clusters of surge-type glaciers in mid-latitude mountain regions.
Modelling the propagation of flux ropes in the coronal model COCONUT
Authors: linan luis , Regnault Florian , Perri Barbara , Brchnelova Michaela , Kuzma Blazej , Lani Andrea , Poedts Stefaan
Published: February 2023

Some space weather forecasting tools, such as the EUropean Heliosphere FORecasting Information Asset (EUHFORIA), consist of two parts. The first is a semi-empirical coronal model used to create the background solar wind, and the second is a heliospheric model in which coronal mass ejections (CMEs) are injected through the inner boundary located at 0.1 AU. In these models, the inserted CME does not interact with the solar wind before the inner boundary. To take this interaction into account and provide a more realistic description of CMEs at 0.1 AU. We studied the propagation of flux ropes from the solar surface to 0.1 AU in a full magnetohydrodynamic coronal model called COCONUT (COolfluid COroNal UnsTructured). The CMEs were modeled using the modified Titov-Démoulin model (TDm) of flux rope. We tracked the evolution of twenty four different twisted flux ropes within realistic corona configurations reconstructed by COCONUT from the GONG magnetic maps of both minimum and maximum solar activity. All CMEs are identical except for their net initial current. Our results reflect dynamic expected by the standard flare model, such as presence of post-flare loops and the pinching of the CME's legs. However, the shape of the CME varies greatly depending on whether the solar wind corresponds to a minimum or a maximum activity, highlighting the crucial role of the solar wind in determining the geometry of CMEs. Once the flux ropes reach 0.1 AU, their thermodynamic and magnetic properties are extracted. We found that, for the two solar wind configurations, the synthetic profiles obtained are consistent with those that satellites could measured. Moreover, simple relationships are emphasised between the net initial current of flux ropes and the shape of the different synthetic profiles.  Finally, using this CME description, the boundary conditions imposed on EUHFORIA (or other heliospheric models) should be more accurate than those provided by an independent CME model and therefore lead to more realistic forecasts.​ 
Statistical and hydrological evaluation of precipitation estimates and simulations from the remote sensing technologies and WRF modeling over the Peruvian Andes region
Authors: Chen Mengye , Huang Yongjie , Li Zhi , Mamani Larico Albert Johan , Xue Ming , Hong Yang , Hu Xiao-Ming , Mayol Novoa Hector , Martin Elinor , McPherson Renee , Vitaliano Perez Andres , Yanqui Morales Isaac
Published: February 2023

Peruvian Andes region has been proven in multiple studies to be one of a few regions have poor performance of many global precipitation estimations, due to its complex terrain and extreme interruption of atmospheric movement by the Andes mountain. This study provides an evaluation over two Peruvian local precipitation products PISCO and RAIN4PE, along with a regional dynamic downscaled WRF model simulation, and GPM-IMERG. The precipitation products were evaluated against local rain gauge data and used as the forcing data for CREST-VEC model to test the uncertainties of the precipitation products in a extremely dry region in Peru. This study readdress the accuracy issue of precipitation products in the Peruvian Andes region, and highlights the importance of using WRF modeling simulation to ‘fill-the-blank’ of heterogenous rain gauge distribution, when remote-sensing technologies fail to perform in this area.
Progress on PTB’s transportable Al+ ion clock
Authors: Nauk Constantin , Kraus Benjamin , Hinrichs Jost , Callegari Simone , Hannig Stephan , Schmidt Piet
Published: February 2023

Optical atomic clocks achieve fractional systematic and statistical frequency uncertainties on the order of 10−18. This enables novel applications, such as height measurements in relativistic geodesy with ∼ 1 cm resolution for earth monitoring. Towards this goal, we set up a transportable clock based on the 1S0 → 3P0 transition in 27Al+. A co-trapped 40Ca+ ion allows state detection and cooling via quantum logic spectroscopy and sympathetic cooling.We unveil the design and the current status of the transportable apparatus and review the recent development of the laser systems. In particular, we present the clock laser setup emitting at 267.4 nm based on single-pass frequency-quadrupling which allows phase stabilization of the complete path. Furthermore, we show the performance of the fundamental frequency to reach a fractional frequency uncertainty of ~ 10−16 at 1 s.
Ghub: A new community-driven data-model resource for ice-sheet scientists
Authors: Goliber Sophie , Briner Jason , Nowicki Sophie , Csatho Beata , Jones-Ivey Renette , Lipscomb William , Patra Abani , Poinar Kristin , Quinn Justin , Schenk Anton , Thayer-Calder Katherine
Published: February 2023

The urgency in reducing uncertainties of near-term sea level rise relies on improved modeling of ice sheet response to climate change. Predicting future ice sheet change requires a tremendous effort across a range of disciplines in ice sheet science, including expertise in observational data, paleoglaciology, numerical ice sheet modeling, and the widespread use of emerging methodologies for learning from the data. However, significant knowledge and disciplinary barriers make collaboration between data and model groups the exception rather than the norm. We seek to improve the efficiency in collaboration among traditionally disparate approaches to this problem. We present Ghub, a community-building scientific and educational cyberinfrastructure framework that includes models and data processing tools, online simulation, and collaboration support, available for use at theghub.org. Ghub enables collaboration between ice sheet scientific communities and acts as a host for the open-source tools that are becoming more common in the field of ice sheet science. We provide an overview of the Ghub framework, with examples of tools, tutorials, and educational content that are ready to use, and visions for extending these and other upcoming developments. These tools target a wide range of audiences, ranging from ice sheet modeling community efforts such as the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6) to more specialized process-orientated investigations. We also outline the process for scientists to host their data and tools on the platform.
New insights into Jovian radio emissions
Authors: Louis Corentin , Kurth William , Bolton Scott , Boudouma Adam , Collet Brieuc , Elliott Sadie , Hospodarsky George , Imai Masafumi , Jackman Caitriona , Lamy Laurent , Louarn Philippe , Martos Yasmina , Sulaiman Ali , Zarka Philippe
Published: February 2023

Jupiter is the planet with the most intense and extensive radio radiation in our solar system. The radio spectrum is composed of no less than half a dozen components, from low-frequency emissions, such as quasi-periodic bursts (QP) or trapped continuum radiation (from a few kHz to tens of kHz), to high-frequency emissions produced over the poles, ranging from a few MHz to 40 MHz. Since July 2016, Juno has been orbiting Jupiter, performing a polar orbit every 53 days during its prime mission, sampling all latitudes, longitudes and local times. These polar orbits allow Juno to pass directly into the auroral zones, where electrons are accelerated and produce the auroral radio emissions, but also through the plasma disk, where other types of radio emissions are produced. 

In this presentation, I will focus on the main results obtained by Juno during its main mission concerning radio emissions, and show how radio emissions can be used to infer in situ conditions.
Naturally Occurring Asbestos in the asbestos-free European Union approach. Is asbestos exposure prevention being understood correctly?
Authors: Hyskaj Ambra , Schimek Éva , Weiszburg Tamás , Harman-Tóth Erzsebet
Published: February 2023

The recent European Green deal is bringing up issues on occupational health mostly related to the hazardous material exposure. Due to the implementation of the Renovation Wave Strategy, increased asbestos exposure is expected. Following this, the European Commission has come with acts proposed to better protect people from asbestos exposure, focusing on occupational exposure.We have analyzed the European Parliament activity related to asbestos from 1995 to 2022 focusing on the questions, proposals and debates brought by the Members of the European Parliament and the European Commission. There were 425 questions raised by the MEPs to the European Commission. While most of the question subjects were related to built-in asbestos and asbestos containing material waste management, only 4 questions were brought up for the natural environmental exposure from asbestos. Naturally Occurring Asbestos (NOA) is currently a case out of any legislative scope in the European Union.Even though NOA is now being recognized in the impact assessment accompanying the proposal to amend the Asbestos Work Directive (Directive 2009/148/EC), it is once more left in national level focus and responsibility to pay attention to. All kinds of asbestos, being already considered carcinogen agents of group 1, have the possibility to be a source of natural hazardous material exposure to the general population, not only to the workers (during construction, renovation, demolition, waste management activities). European Union is reflecting the ambition to be an international leader in fighting asbestos exposure while is under evaluating the natural source of asbestos minerals risk to general population health. Identifying and registering the presence of asbestos in buildings is simply not enough to protect human health or aiming to accomplish Europe’s Beating Cancer Plan. A database with NOA presence in Europe is needed, together with proper guidelines to manage the natural occurrence in order to support appropriate land use, urban planning, risk management (natural disasters such as erosion), and mining activities in the geologic setting where asbestos fibers are possible to be encountered.