bluuebunny/crossref_metadata_2025 huggingface dataset:
Separation of signal components in global gravity models
Authors: Heller-Kaikov Betty , Pail Roland , Werner Martin
Published: February 2023

Vertical movements of the Earth’s surface represent mass displacements, which cause a temporal gravity signal that can be measured by dedicated satellite gravity missions such as the GRACE or GRACE-FO missions. Especially observations of vertical movements that are caused by mantle dynamic processes would enable to constrain numerical mantle convection models using geodetic data sets, thereby improving our understanding about the physical behavior of the Earth’s interior.Using satellite gravity data to observe the above-mentioned vertical movements poses two main challenges:First, the small amplitudes of the geoid trend signals induced by mantle dynamic signals require data accuracies and record lengths that will only be met by future satellite gravity missions. Indeed, it is known from previous simulation studies that temporal gravity signals produced by mantle convection will be detectible in future double-pair satellite gravity missions such as the planned Mass Change and Geoscience International Constellation (MAGIC).The second challenge to make use of gravity data sets for constraining geophysical mantle models is the extraction of the signal of interest from the total gravity signal. While temporal gravity data sets include the cumulative mass displacement signal, the problem of how to separate the superimposed signals produced by phenomena in the hydrosphere, cryosphere, atmosphere, oceans and solid Earth is still unsolved.In this contribution, using the gravity signals given by the updated ESA Earth System Model, we address the task of signal separation in temporal gravity data and present two approaches for it. To this end, the knowledge of the spatial and temporal characteristics of the individual signal components is exploited by applying principal component analysis as well as a machine learning approach.
Identification of a hidden fault associated with the Mw 5.6 (November 21, 2022) Cianjur Earthquake, West Java, Indonesia
Authors: Supendi Pepen , Winder Tom , Rawlinson Nicholas , Bacon Conor , Daryono Daryono , Simanjuntak Andrean , Palgunadi Kadek Hendrawan , Shiddiqi Hasbi Ash , Kurniawan Andri , Priyobudi Priyobudi , Widiyantoro Sri , Nugraha Andri Dian , Adi Suko Prayitno , Karnawati Dwikorita
Published: February 2023

A destructive earthquake (Mw 5.6) struck Cianjur, West Java, Indonesia, on 21 November 2022, resulting in at least 321 deaths, damage to 47,000 buildings, and economic losses of up to 7.7 trillion Indonesian Rupiahs (∼US $546 million). The causative fault that generated this earthquake was not previously recognised, therefore making further analysis crucial for assessing future seismic hazard in the region. In this study, we undertake automated event detection and location using QuakeMigrate from 10 days before to 23 days after the mainshock, prior to relocation using a double-difference method. We also determine the source mechanism for selected aftershocks from waveform inversion. Our result show that the mainshock was preceded by three clear foreshocks, and intriguingly the aftershocks appear to reveal the presence of a conjugate fault pair trending northwest-southeast with a length of ~8 km and southwest-northeast with a length of ~5 km.
PBL-Aerosol-Interactions and Impact on Turbulent Entrainment
Authors: Li Zhanqing , Su Tianning
Published: February 2023

Aerosol-boundary layer interactions play an important role in affecting atmospheric thermodynamics and air pollution. As a key factor in dictating the development of the boundary layer, the entrainment process in the context of aerosol-boundary layer interactions is still poorly understood. Using comprehensive field observations made at a superstation in Beijing, we gain insight into the response of the entrainment process to aerosols. We found that high aerosol loading can significantly suppress the entrainment rate, breaking the conventional linear relationship between sensible heat fluxes and entrainment fluxes. Related to aerosol vertical distributions, aerosol heating effects can alter vertical heat fluxes, leading to a strong interaction between aerosols and the entrainment process in the upper boundary layer. Such aerosol-entrainment coupling can inhibit boundary layer development and explains the great sensitivity of observed entrainment rates to aerosols than can traditional calculations. The notable impact of aerosols on the entrainment process raises holistic thinking about the dynamic framework of the boundary layer in a polluted atmosphere, which may have a significant bearing on the dispersion of air pollutants and the land-atmosphere coupling
Drought mortality and resilience of savannas and forests in tropical Asia
Authors: Scheiter Simon , Kumar Dushyant , Pfeiffer Mirjam , Langan Liam
Published: February 2023

The projected increase of drought occurrence under future climates will affect terrestrial ecosystems, particularly by increasing drought-induced tree mortality. The capacity to simulate drought mortality in vegetation models is therefore essential to understand climate change impacts on ecosystem functions and services, as well as on functional diversity. Using the trait-based vegetation model aDGVM2, we assessed tree mortality under drought conditions in tropical Asia under future climate, and if vegetation is resilient to drought or if tipping point behavior occurs. We further assessed how drought impacts are related to pre-drought community composition and diversity. We conducted model simulations for multiple sites in tropical Asia, representing a biogeographic gradient ranging from savannas to tropical forests. Responses of vegetation attributes and mortality rates were simulated until 2099 under the RCP8.5 scenario. Repeated droughts of different length were modeled to test drought impacts and resilience. Finally, the diversity of pre-drought communities was constrained by removing different trait syndromes to test how community composition and diversity influence drought resistance and resilience. Model simulations showed substantial biomass dieback during drought which was attributed to increased mortality rates, primarily among tall and old trees. Drought response differed between current and elevated CO2 levels under RCP8.5, with higher biomass recovery under elevated CO2 due to fertilization effects. Pre-drought community composition influenced biomass dieback and mortality during drought, and the presence or absence of drought-adapted plants had the highest effect on drought impacts. Despite severe drought impacts, recovery of most vegetation attributes was possible after drought periods. We conclude that repeated droughts under future conditions will have vast impacts on vegetation attributes and mortality in tropical ecosystems. Conserving functional diversity in ecosystems buffers drought impacts. However, according to model results, vegetation is resilient, and irreversible transitions to alternative vegetation states do, for the investigated scenarios, not occur. Improved models representing lagged drought impacts, irreversible damage of individual plants, and the interactions between drought regimes, CO2 fertilization and trait diversity are required.
Wheat yields in Kazakhstan can successfully be forecasted using a statistical crop model
Authors: Romanovska Paula , Schauberger Bernhard , Gornott Christoph
Published: February 2023

The COVID-19 pandemic, recent extreme weather events around the globe and the invasion of Russian forces in Ukraine have led to a disrupted global food market. As the 12th largest global wheat exporter, Kazakhstan is fundamental for regional and global food security. Timely and reliable predictions of Kazakh wheat production could therefore improve food security planning and management in Central Asia and beyond.
In this session, we want to present a statistical weather-driven yield forecast model that is run with publicly available weather and yield data and requires low computational power, making it easily replicable. Decision makers in Kazakhstan have expressed high interest in using the forecast model as a replenishment to currently applied work-intensive forecasting methods. We stringently evaluated our model in a double out-of-sample validation and used it to forecast total national wheat production in a fully blind run for 2022.
Our results show that the model can successfully hindcast wheat yields at the oblast (regional) level up to two months before the harvest. The hindcast of wheat yields for 1993 to 2021 produces a median R2 of 0.69 for the full model run and R2 values of 0.60 and 0.37 for two levels of out-of-sample validations, respectively. Based on these yield estimates we provide a robust hindcast of the total wheat production for Kazakhstan with an R2 value of 0.86 (0.81 and 0.73 for two levels of out-of-sample validations). We forecast total wheat production in Kazakhstan for 2022 to be 12.4 million tonnes and thus 5 % above the production of the last year.
Regional impacts of CO and NOx mitigation in a methane emissions-driven model
Authors: Staniaszek Zosia , Griffiths Paul T , Folberth Gerd A , O'Connor Fiona M , Archibald Alexander T
Published: February 2023

Methane plays a central role in the atmosphere, affecting the atmospheric oxidising capacity through its reaction with OH, air quality through its role as an ozone precursor, and climate through its greenhouse gas properties.  Methane emissions-driven models provide an opportunity to study the Earth system within a global model that features the most accurate representation of the methane cycle. Here we use the methane emissions-driven configuration of the UK Earth System Model, UKESM1-CH4. Previously we explored a zero anthropogenic methane scenario, which focused on attributing the composition, air quality and climate impacts of future anthropogenic methane emissions. Here, we study the potential co-benefits of methane mitigation: reducing NOx and CO emissions. We use SSP1-2.6 emissions pathways for CO and NO in these scenarios. The complex interactions between methane, CO, OH and NOx are represented more completely in the emissions-driven model. We calculate the sensitivity of ozone and OH to the CO and NO emissions changes, and their dependence on the methane burden. We also show the impacts on other near-term climate forcers such as aerosols and ozone. Global reductions in CO and NO emissions have disproportionate effects in different regions. We present analysis of the regional differences in ozone and OH response, based on the HTAP regions. We demonstrate much greater effects in South and East Asia than in the Europe and North America.
CO2 and CH4 soil exchanges in managed woody species of Sierra Nevada mountains (Spain)
Authors: Agea Plaza Daniel , Aranda-Barranco Sergio , Sanchez-Cañete Enrique, P , García-Berro Ignacio , Valverde-Amor Angela L, , Zamora Regino , Alcaraz-Segura Domingo , Serrano-Ortiz Penelope
Published: February 2023

To avoid tree mortality, biodiversity losses and maintain the ecosystem services under climate change context, the management of forests is essential. A common practice in Mediterranean mountains is clearing and thinning, leaving the main branches lopped off and the wood left in situ. These activities generate bare soil and vegetation pruning patches in the ecosystem creating different microhabitat conditions and, therefore, affecting carbon dioxide (CO2) and methane (CH4) soil exchanges. This study is focused on oak and holm oak groves and pine reforestation, dominant woody species in Sierra Nevada mountains (Spain) that have problems of adaptation to climate change fostered by a long history of human management. On this subject, we are monitoring both with biophysical field measurements and satellite products on the experimental managed forests. Concretely, we are measuring for one year CO2 and CH4 soil fluxes of the different patches. For this purpose, a portable gas analyzer system (Smart chamber + Li7810, Li-Cor) is used biweekly over 24 collars (2 treatments [vegetation pruning vs immediate bare soil] x 3 replicas x 4 collars [sub-replicas]) on each one of the 4 experimental forests (Quercus pyrenaica, Quercus ilex, Pinus halepensis and Pinus sylvestris). At the same time, soil water content, soil temperature and litter are measured in each campaign.  On the other hand, Landsat products (NDVI, LST and LSWI) were evaluated before and after the establishment of the treatments for temporal follow-up. Additionally, since January 2023 we are starting to characterize microclimatic conditions (velocity and direction wind, air temperature, soil water content and precipitation) and continuous CO2 concentration in soils (GMP252, Vaisala).The preliminary results show that oaks with vegetation respires more (soil CO2 emissions) than oak grove bare soil. Although both patches are methane sinks, the CH4 flux is enhanced with vegetation presence. A relationship with soil temperature and moisture was found. We hypothesize that these variations could be due to autotrophic respiration, and more prolonged activity of microorganisms in the soil enhanced by litter input. Regards pines sites, no significant differences in fluxes of the different microclimate’s patches were found (no relationship with soil variables was detected) which seems to indicate that the management leaving vegetation pruning does not affect soil fluxes.This work was supported by the projects B-RNM-60-UGR20 (OLEAGEIs) and LifeWatch-2019-10-UGR-01, co-funded by the MICINN through the FEDER funds.
A systematic review of the use of theories in social vulnerability, resilience, and adaptation research
Authors: Madruga de Brito Mariana , Kuhlicke Christian , Bartkowski Bartosz , Botzen Wouter , Doğulu Canay , Han Sungju , Hudson Paul , Karanci Ayse Nuray , Klassert Christian , Otto Danny , Scolobig Anna , Moreno Soares Thais , Rufat Samuel
Published: February 2023

There is an increasing rise in the number of publications addressing social vulnerability, resilience, and adaptation (SVRA) aspects of natural hazards and climate change. Despite the abundance of research in this field, a systematic understanding of how these studies are theoretically grounded is lacking.In this study, we conducted a systematic review of 4432 articles that address SVRA across a range of disciplinary fields (e.g. psychology, sociology, geography, mathematics) and natural hazards (e.g. floods, droughts, landslides, storm surges, wildfires, tsunamis, earthquakes, and volcano eruptions). We investigate the extent to which these studies explicate the frameworks, theoretical constructs or theories they rely on.Our findings indicate that about 90% of the studies under consideration do not explicitly refer to a theoretical underpinning. Overall, theories focusing on individuals' SVRA were more frequent than those focusing on systems, society, groups, and networks. Furthermore, the uptake of theories varied according to the hazard investigated and field of knowledge, being more frequent in wildfire and flood studies and articles published in social science journals.We argue that the abundance of empirical material in SVRA research that lacks explicit theoretical grounding is objectionable. As a result, SVRA research seems to spin in circles: researchers repeatedly conduct similar analyses in different geographical settings with inconsistent or incommensurable findings. Thus, we recommend making theoretical considerations salient to foster more transparent, comparable, and robust empirical research on SVRA.
A methodological framework to map and assess lake ecosystem services: a multi-temporal analysis study in Lithuania
Authors: Inácio Miguel , Pereira Paulo
Published: February 2023

The importance of freshwater ecosystems is pivotal for human well-being. Lakes, recognized as essential water reservoirs, these ecosystems support the provision of a wide array of ecosystem services (ES) across reams (terrestrial and aquatic). However, anthropogenic activities increase environmental degradation. Consequently, its contribution as ES provider may decrease over time. Thus, it is essential to analyze lake ES assessment over time. Mapping and assessment methodologies for lake ES assessment are scarce. Moreover, indicator data is limited in space and time. Therefore, most ES mapping and assessment research is conducted on a case study basis, focusing on qualitative approaches. Comprehensive quantitative national lake ES mapping and assessments are largely missing but necessary. In this study, we develop quantitative methodological frameworks to map and assess lake ES nationally. The methodologies were applied to Lithuania, which comprises more than 1000 lakes. Since all lakes were unavailable, we utilized information from the HydroLAKES database. The methods use freely available data from national and international databases and remote sensing imagery. In total, 5 ES, defined based on the Common International Classification of Ecosystem Services (CICES), were analyzed: (1) fibers and other material for non-nutritional purposes; (2) water for non-drinking purposes; (3) maintenance of nursery conditions; (4) maintenance of chemical conditions; and (5) recreation. Since lake ES are influenced by their surrounding terrestrial dynamics (e.g., nutrient flows, noise), we included a 5 km buffer around each lake. Land-use dynamics were assessed using Corine Land Cover for 1990, 2000, 2006, 2012, and 2018. The testing of methodology results allowed us to identify general patterns of lake ES supply in Lithuania. The ES fibers and other materials for non-nutritional purposes show a higher supply in the eastern part of Lithuania, which generally increased from 1990 to 2018. The ES water for non-drinking purposes shows only slight changes in its supply over time. The maintenance of nursery and chemical conditions ES show a decline in the supply over time, especially in the northeastern part of the country. The ES recreation also shows nearly no changes in its supply over time.This study was conducted under the framework of the “Lithuanian lake ecosystem services: impacts of climate and land-use change” (LACLAN) Project. This project receives funding from the European Social Fund under the No 09.3.3-LMT-K-712 “Development of Competences of Scientists, other Researchers, and Students through Practical Research Activities” measure. 
Sensitivity of micro-scale atmospheric processes in a city quarter of Berlin, Germany on elevated meso-scale temperature forcing
Authors: Scherer Dieter , Scherber Katharina , Fehrenbach Ute , Meier Fred , Otto Marco , Schmidt Benjamin , Steikert Ralf , Holtmann Achim
Published: February 2023

During heat waves, urban dwellers are exposed to elevated temperatures, especially during night-time when urban heat island (UHI) effects are most intense. Climate change is expected to further increase heat-stress hazards. There are only few studies that have investigated how UHI effects interfere with heat waves. Here, we present results from a sensitivity study in which we analyse non-linear effects of elevated meso-scale temperature forcing on micro-scale atmospheric processes. The study employs the large eddy simulation model PALM-4U. The ‘Tempelhofer Feld’ in Berlin, Germany, the largest park within the city, was used as study area. Starting point was a 24 h (plus 6 h spin-up) control simulation followed by a scenario simulation in which all temperature variables, not only air temperature, were increased by 1 K. The control simulation was configured to represent a real weather situation in an idealized form. Grid spacing was set to 10 m horizontally and 2 m vertically to resolve buildings and trees. A residential area to the east of the airport was simulated with a higher horizontal grid resolution of 2 m to investigate micro-scale atmospheric processes in more detail. The results show that the micro-scale response of near-surface air temperature to elevated meso-scale temperature forcing is not constant throughout the day with lower values during day-time and higher values during night-time, particularly in the early evening. In both simulations, the night-time inversion over the park continues into the settlement above the roof level. The study shows that there are weak non-linear effects leading to an amplification of the UHI during night-time. However, as linear effects dominate, adaptation measures with regard to heat stress may be planned on the basis of current weather and climate conditions, additionally documented by observational data, and subsequently evaluated by urban climate monitoring.
Adoption of rainwater harvesting systems for agricultural irrigation to improve water management
Authors: Velasco Muñoz Juan F. , López Felices Belén , Balacco Gabriella , Aznar Sánchez José A.
Published: February 2023

In many production areas, water is the main limiting factor for agricultural development. The consequences of global climate change, population growth, changes in land use and overexploitation due to economic growth have caused water resources to be subject to severe degradation. As the main consumer of water resources, water use in this sector is of great importance. However, the wide variety of stakeholders and the need for food supply make the management of agricultural systems very complex. In this context, it is necessary to incorporate water management practices and technologies that contribute to the sustainability of agricultural activity. To ensure the success of these practices, their choice and adoption must take into account the interests of different stakeholders. Therefore, the first objective of this work is to identify the sustainable water management practices that are best suited to the context of the study area, as well as the main barriers and facilitators to their incorporation. For this purpose, several qualitative research tools are used in consecutive phases (literature review, in-depth interviews, Delphi method and workshop). The results show that the most suitable practice for mainstreaming is rainwater harvesting (RWH). Facilitators for the adoption of this practice include the existence of farmer networks and access to the necessary technology, while installation costs and certain characteristics of the study area and farms act as main barriers. The second objective of this work was to identify the factors affecting farmers' decision to adopt RWH systems to use harvested water for agricultural irrigation. For this purpose, farmers in the study area were surveyed and a binary logistic regression model was carried out. The variables found to be significant in explaining farmers' behaviour were age, educational level, farm size, pond capacity and volume, income and level of environmental awareness.
Uncovering the Processes that Control Induced Earthquake Sequences
Authors: Cochran Elizabeth , Kroll Kayla , Page Morgan , Ross Zachary , Rubinstein Justin
Published: February 2023

Earthquake sequences induced by fluid disposal into the subsurface show strong variability in their magnitude distributions and clustering behavior. We attempt to untangle the processes that control the occurrence and evolution of disposal-induced earthquake sequences by integrating detailed seismicity observations, pore pressure modeling, and 3D physics-based earthquake simulations. Observations of earthquake sequences in Oklahoma and Kansas include some sequences that have near-Poissonian distribution of interevent times and robust foreshock sequences, while other sequences display more typical mainshock-aftershock clustering behavior. Pore-pressure modeling shows that these behaviors correlate with the amplitude of the pore-pressure changes. Close to disposal wells where pore pressure changes are high, seismicity is controlled by both diffusion and earthquake stress interactions. Farther from the wells where pore pressure changes are lower, seismicity appears driven primarily by stress interactions. We further explore the stress and fault conditions that may allow for these diverse behaviors using an earthquake simulator, RSQSim. We find that the maximum magnitude of the triggered events depends strongly on the pre-existing stress on the fault. The roughness, distribution, and background stress state of pre-existing primary and secondary faults also likely influence the sequence behavior and is an area of ongoing work.  
The Box Corer Imaging System: A low-cost solution for in-situ seafloor imaging and sampling.
Authors: Betzler Christian , Eisermann Jan Oliver , Reolid Jesus
Published: February 2023

Sediment sampling of the seafloor, especially with a box corer, is an important aspect of marine geology and sedimentology. The sediment surface recovered by this tool, however, is of limited extend (10s of cm only) and might be disturbed thru the sampling process. The Box corer Imaging System (BOXIS) is an addon for the box corer allowing for high resolution video recording of the sampling process. It attaches to the box corer main frame and adds lights, batteries and a camera. The system can be adapted to a variety of sampling devices. Its main objective is to capture video of the sample area before and after the sampling of which images can be extracted. The recording is extracted after the sampling process, when the tool is on deck. The system is equipped with LED lights featuring a total of 7000 lumens and built-in redundancy. The separate light units are connected via cable to their corresponding battery unit featuring a custom timer and magnetic activation switch. The special camera housing features a popular action camera recording at 5.3K resolution (19.6 Mpx). The camera field of view features a wide, undistorted, unobstructed view looking down. As a benefit of the camera position, depending on visibility it is possible to gather images from up to 10 m above the seafloor conveying a broader context down to close-ups 25 cm from the seafloor. The BOXIS system is rated to a maximum operation depth of 1750 m. The BOXIS footage can be examined instantly over a wireless connection on a mobile device once the box corer is back on deck to evaluate sampling quality and support discussion and decision making on the proceeding of further sampling operations. Large batteries ensured multiple deployments in a row without service. Even in cases where the box corer does not trigger, the BOXIS provides data not only of the seafloor but also on operational problems such as sediment penetration. It is a system with a minimum of cabling, which therefore is not endangered to interact with the hoisting equipment used for lowering and lifting of the normally analog gear.The BOXIS system has been successfully deployed for the first time on FS SONNE cruise SO292 in spring 2022 to the Queensland plateau, Australia. In total we could record a total of 27 deployments without a single failure. We will present the BOXIS system based on examples from these successful deployments.
Is WaPOR precipitation data reliable over Iran?
Authors: Moghaddas Mohsen , Tajrishy Massoud
Published: February 2023

As a result of satellite observations, ground observations, and data assimilation, global precipitation datasets have been developed for regions like Iran, where ground observations are limited. This study presents a comprehensive evaluation of WaPOR precipitation dataset over Iran at daily time scale. We considered a period of three years from 2019 to the end of 2021 and 394 synoptic rain gauges are used for the assessment. Daily WaPOR precipitation data at 250m scale downloaded and compared pixel-to-point with in-situ data. In addition, the WaPOR data and stations data were compared based on time classification (seasonal), location in the main catchment basins of Iran, and elevation above sea level. Calculating MSE, R score, RMSE and MSLE between real data(stations) and predict data(Wapor) shows some important result: 1. From the time point of view, WaPOR has best performance in summer (MSE = 4.94 and MSLE = 0.16) 2. Location, the best performance is related to stations of the catchment areas of the eastern part of Iran (Qaraqom basin with MSE = 11.9 and eastern border basin with MSE = 6.26) and the worst performance is related to the catchment area of the Caspian Sea (Mazandaran Sea basin with MSE = 64.06). 3. For analyzing the effect of elevation on precipitation, we divided the stations into 5 groups with an interval of approximately 600 meters (according to the lowest and highest elevation, which is -25 meters and 2965 meters). The best performance is related to stations with an altitude between 572 and 1170 meters (MSE = 21.61) and the worst is related to stations with an altitude between 1768 and 2366 meters (MSE = 43.79). 4. Moreover, on average for each station, in the three years of study (1096 days), we have 166 days (with standard deviation 119 days) that station has recorded precipitation but WaPOR dataset didn’t represent any record, so it’s not appropriate for daily hydrological models. 5. The difference between the three-year precipitation total at the station and the WaPOR precipitation total is 449.6 mm on average (with standard deviation 724.5).
Residence time of crystals in a thermally convecting magma reservoir
Authors: Patočka Vojtěch , Tosi Nicola , Calzavarini Enrico
Published: February 2023

The dynamic behaviour of crystals in convecting fluids determines how magma bodies solidify. In particular, it is often important to estimate how long crystals stay in suspension in the host liquid before being deposited at its bottom (or top, for light crystals and bubbles of volatiles). We perform a systematic 3D numerical study of particle-laden Rayleigh-Benard convection, and derive a robust model for the particle residence time. For Rayleigh numbers higher than 107, inertial particles' trajectories exhibit a monotonic transition from fluid tracer-like to free-fall dynamics, the control parameter being the ratio between particle Stokes velocity and the mean amplitude of the fluid velocity. The average settling rate is proportional to the particle Stokes velocity in both the end-member regimes, but the distribution of residence times differs markedly from one to the other. For lower Rayleigh numbers (<107), an interaction between large-scale circulation and particle motion emerges, increasing the settling rates on average. Nevertheless, the mean residence time does not exceed the terminal time, i.e. the settling time from a quiescent fluid, by a factor larger than four. An exception are simulations with only a slightly super-critical Rayleigh number (~104), for which stationary convection develops and some particles become trapped indefinitely. 2D simulations of the same problem overestimate the flow-particle interaction - and hence the residence time - for both high and low Rayleigh numbers, which stresses the importance of using 3D geometries for simulating particle-laden flows. We outline how our model can be used to explain the depth changes of crystal size distribution in sedimentary layers of magmatic intrusions that are thought to have formed via settling of a crystal cargo, and discuss how the micro-structural observations of solidified intrusions can be used to infer the past convective velocity of magma.
Optical properties of birch pollen using a synergy of three lidar instruments
Authors: Filioglou Maria , Leskinen Ari , Vakkari Ville , Tuononen Minttu , Shang Xiaoxia , Komppula Mika
Published: February 2023

Pollen has important implications for health, but also for the climate as it can act as cloud condensation nuclei or ice nuclei in cloud processing. Active remote sensing instruments equipped with polarization capability can extend the detection of pollen from the surface up to several kilometres in the atmosphere maintaining continuous and high time resolution operation. In this study, we use a synergy of three lidars, namely, a multi-wavelength PollyXT lidar, a Vaisala CL61 ceilometer and a Halo Photonics StreamLine Doppler lidar, to investigate the optical properties of birch pollen particles. All three lidars are equipped with polarization channels enabling the investigation of the wavelength dependence at 355, 532, 910 and 1565 nm. Together with pollen observations from a Hirst-type spore sampler and aerosol in situ observations, we were able to characterize the linear particle depolarization ratio (PDR) and backscatter-related Angstrom exponents of the pollen particles. Both optical properties have been extensively used in aerosol classification algorithms and they are therefore highly desired in the lidar community. We found that birch pollen exhibits a spectral dependence in the PDR, and its classification is feasible when, preferably, two or more polarization wavelengths are available.
Deflection/Rotation of Earth-directed CMEs
Authors: Karuppiah Suresh , Dumbovic Mateja , Martinic Karmen , Temmer Manuela , Veronig Astrid , Chikunova Galina , Podladchikova Tatiana , Dissauer Karin , Heinemann Stephan , Vrsnak Bojan
Published: February 2023

Coronal mass ejections (CMEs) are the major eruptive phenomena that cause various space weather effects. CMEs can be deflected by coronal holes (CH) away or towards the Sun-Earth line depending on their relative location, and also the high speed streams from CH can influence CME propagation. Coronal dimmings which are away or toward the CH may also cause CME deflection. The main aim of our study is to analyse the deflection/rotation of CMEs by tracking them in COR1 and COR2 field of view of STEREO onboard SECCHI with the help of 3D reconstruction Graduated cylindrical shell (GCS) model. We analyse 60 Earth-directed CMEs and their associated low coronal signatures observed in SDO/AIA. In addition, with the help of CATCH tool we study the nearby coronal hole parameters. Furthermore, we analyze the associated coronal dimmings by considering the movement of secondary dimmings towards or away the nearby CH. Out of 60 events, 31 events show deflection/rotation, as we track them from 1.76R☉ to 20.8R☉. A small fraction of (11%) events show deflection in longitude, and a significant fraction of events show deflection in latitude (38%) and rotation (40%). We discuss these results with respect to the vicinity and direction of coronal holes.
Tephra compositional data: are we doing it right?
Authors: Larsson Simon , Bolton Matthew
Published: February 2023

Tephrochronology is often used for dating of natural archives and for correlation between study sites. Volcanic ashes (tephra) extracted from cores used for climate reconstructions function as common time-marker horizons and become anchor points in comparisons of age models from different studies. Given these uses, tephrochronology is well placed to help overcome the chronological challenges that hinder sufficiently precise dating of palaeoclimate records.Tephras are identified based on their geographic and stratigraphic contexts, glass shard morphology, and geochemical composition. The geochemistry is most commonly analysed by electron probe microanalyser and presented as weight percentages of oxides of the nine or ten most abundant elements, often normalised to a 100 % total for ease of comparison. A simple exploration of such results and comparison to published data of previous tephra findings is usually enough for confident identification. However, compositional data of tephra findings from new studies continuously add to the complexity of tephrochronological investigations by increasing the amount of data available for comparison, including the addition of new potential candidates for identification. The increased likelihood of multiple candidates—sometimes with overlapping geochemistries—means that statistical data analyses are increasingly necessary.Tephrochronologists have used principal component analysis and discriminant function analysis in situations needing statistical approaches, but these methods’ validity often requires certain assumptions not to be violated. A rarely considered example of such an issue is that compositional data suffers from the constant-sum constraint and must be converted by log-ratio transformations for some statistical analyses to function properly. As there is presently no consensus on a tephra compositional data curation procedure including log-ratio transformations, we have explored several variations and compared the results to see if a formal recommendation for such a procedure is relevant for the tephra community.
The changes of Tea Bag Index parameters depending on the radionuclide contamination level of soils in northern Ukraine
Authors: Illienko Volodymyr , Volkohon Ivan , Klepko Alla , Lazarev Mykola
Published: February 2023

Huge soil areas in the northern Ukraine were contaminated with artificial radioactive isotopes after the accident at the Chornobyl nuclear power plant in 1986. Meanwhile, the levels of radionuclide pollution in these areas vary widely, which creates unique opportunities to conduct studies on the impact of the ionizing radiation (IR) on the soil health including functioning of soil microorganisms in field conditions.We aimed to study the cellulose-destroying activity of the soil microflora at elevated radionuclides contamination. Two experimental sites were chosen – 1) near the exclusion zone (site 1), but outside its borders, and 2) in the exclusion zone (site 2). Both sites were characterized by a significant gradient of radionuclide contamination and the absorbed dose rate (ADR) of IR was formed due to activity of two isotopes 137Cs and 90Sr. We selected three points with ADR of 0.2, 1.0  and 1.6 μGy/hour in the upper soil layer at the site 1 and three points with ADR 3.7, 22.2 and 61.6 μGy/hour in the upper soil at the site 2. The physico-chemical soil properties and climate condition did not differ between all points of one site.The rate of OM decomposition by soil microorganisms at all experimental points was determined by using the standardized Tea Bag Index (TBI) method (Keuskamp et al., 2013). We used two types of tea bags TM Lipton©: green tea and rooibos as a standardized plant material to determine decomposition rate (k) and stabilization factor (S), percentage of decomposed fast disintegrated litter compounds - green tea (g) and more recalcitrant litter compounds – rooibos (r), respectively.Two burials of plant material (=tea bags), each time for 90 days, were made: 1) from April to June 2021; and 2) from July to September 2021.At the site 1, S and g values did not differ among points with different ADR levels. At the same time, k and r values statistically reliably increased with an increase of IR ADR.At the site 2, S and g values significantly changed as the IR ADR increased. S values decreased, and g values, on the contrary, increased. k and r values increased statistically significantly with IR ADR increase as at site 1.These results indicate the stimulating effect of relatively small IR doses (site 1) on the functioning of cellulose-destroying microorganisms, which capable to use more recalcitrant litter compounds (i.e., rooibos). At the same time, high IR doses (site 2) accelerate decomposition processes of both litter compounds. We conclude, that small doses of ionizing radiation will not affect soil quality in terms of the functioning of cellulose-destroying microorganisms. In general, our results could help to better understand how IR affects the processes of soil organic matter (OM) transformation. We acknowledge the National Research Foundation of Ukraine for the financial support of this research (Project number 2020.01/0489).
Modelling of a wildfire in Portugal using a fully coupled atmosphere-fire spread modelling system
Authors: Vaz Ricardo , Silva Rui , Cardoso Pereira Susana , Carvalho Ana , Carvalho David , Rocha Alfredo
Published: February 2023

This work investigates the physical interactions and feedback between wildfires and the atmosphere using the coupled atmosphere-fire spread modelling system, WRF-SFIRE. The Figueira da Foz forest fire, occurred in Portugal in October 2017, which ocurred in association with hurricane Ophelia, was simulated under two different scenarios of fuel moisture settings, one static and one dynamic. Results show an underestimation of burnt area in the dynamic case, while static fuel moisture has shown a very high agreement. Pyrocumulus formed during late afternoon with a very dry base and more humid top, creating conditions favourable for the occurrence of downbursts, with very high Convective Available Potential Energy values. Lifted Condensation Level increased above the fire front as moisture was transported upwards, increasing surface temperature. Official reports show an overestimation of fuel moisture near the surface, leading to high CAPE values, compared to near zero values reported by vertical soundings. Relative Humidity values were higher by 30% when compared to weather station observations, and temperatures approximately 4ºC lower. Further model testing is needed to provide more accurate surface temperature and moisture simulations, to allow a more accurate fire progression representation and energy exchange, and improve the modelling of potential convective events. 
Interstellar Neutral Atom Measurements with IBEX and IMAP
Authors: Sokol Justyna M.
Published: February 2023

Neutral atoms from the interstellar medium around the Sun enter the heliosphere unimpeded by the electromagnetic fields. They bring information about the properties of our interstellar neighborhood, processes at the boundary between the solar and interstellar media, and the direction of the Sun’s motion in the Galaxy. The interstellar neutral atoms of hydrogen, deuterium, helium, neon, and oxygen reach close distances to the Sun where they are probed either by direct detection or remote sensing methods. Here we focus on a direct measurement technique for interstellar neutral atoms of energies from 10 eV to 1 keV on an example of the instruments onboard the Interstellar Boundary Explorer (IBEX) and the follow-up mission the Interstellar Mapping and Acceleration Probe (IMAP, to be launched in 2025). IBEX continuously collects interstellar neutral atom data from the beginning of its operation in 2008 providing a survey over the Solar Cycle 24 despite its observation season being limited during the year. IMAP tracks the beam of interstellar neutrals in the sky throughout the year, which significantly expands scientific opportunities for probing interstellar neutrals from close distances to the Sun. We present the greatest accomplishments of interstellar neutral atom research enabled by IBEX and discuss the science goals in this area for IMAP.The results are presented in collaboration with scientists and researchers at Southwest Research Institute, the University of Bern, the University of New Hampshire, and Princeton University.
Slower drawdown rates in lakes promote the growth and reproduction of lakeshore vegetation
Authors: Dahanayake Amali , Webb Angus , Greet Joe , Brookes Justin
Published: February 2023

Soil erosion on lakeshores due to the fluctuating water levels, waves, and other factors, remain a world-wide problem. Lakeshore vegetation can be helpful in preventing erosion. We investigated the effects of drawdown rate and depth on the growth and reproduction of a keystone lakeshore plant. We hypothesised that plants with access to water for longer would grow better and have higher reproductive output.We subjected 108 Spiny Sedge (Cyperus gymnocaulos) plants to six treatments comprising three drawdown rates (static, slow, fast) and two water depths (shallow and deep). We measured plant stem heights and numbers of flowers and bulbils weekly, and the initial and final biomass of the above ground and below ground components.Plants in treatments without access to water for long periods had the lowest growth and reproductive output. However, if the final water level was deep but drawdown was done slowly, plants were able to maintain similar growth and reproduction rates to plants with continuous access to water.Fluctuating water levels in lakes cause lakeshore plants at lower elevations to be inundated for longer and plants at higher elevations to be deprived of water for longer. Plants located at mid-elevations will thrive if their roots have access to water and their above ground parts are not fully submerged.Our findings are useful to water managers and ecologists concerned about preserving lakeshores from erosion by promoting vegetation. Both the rate and depth of drawdown should be considered in managing lake water levels. Where water levels fluctuate over large depths slower rates of drawdown will enable most plants to have access to water for longer, promoting their growth and reproduction, hence, reducing the lakeshore erosion.  Keywords: lakes, vegetation, drawdown, erosion, sustainability
Investigation of Shallow Subsurface Stress State on the Accretionary Prism off Southwest Taiwan Using Ocean Bottom Seismometers
Authors: Cheng Win-Bin , Hsu Shu-Kun , Lin Jing-Yi
Published: February 2023

A multicomponent ocean-bottom seismometer (OBS) data set collected by National Central University, Taiwan in the accreationary prism off southwestern Taiwan in 2013, 2014 and 2015, respectively. GI-gun shots located at 1 mile and 1.5 miles radius from the OBS, with spacing approximately 40 m along the sailing line that were analyzed as common receiver azimuthal gathers. The OBS recorded data at a sampling rate of 250 Hz and from a shot pattern that gave good azimuthal coverage around the OBS. Methods to obtain information about fractured sediments had developed from these data since anisotropy, an effect of parallel fracture trains, generates birefringence of P-S converted waves. The multicomponent seismic method allows recording the complete wave field, including P-S converted waves. Based on P and P-S converted waves recorded between the direct and multiple arrivals, this experiment targeted the top few hundred meters of sediment in the study area. After preliminary processing, including a static correction, the data were optimally rotated to radial (R) and transverse (T) components. The principal technique used to detect the anisotropy was azimuthal stacking of the radial and transverse horizontal geophone components. The R component shows azimuthal variation of travel-time indicating variation of velocity with azimuth; the corresponding T component shows azimuthal variation of amplitude and phase. From the radial component azimuthal gather and mode-converted wave amplitude variation for the first few layers and determined corresponding anisotropy parameter and Vp/Vs values. Significant result found that implies a presence of natural fracturing direction. We attribute the observed azimuthal anisotropy to the microcrack distribution and grain boundary orientation due to stress since fracture at this depth is not likely to occur.