bluuebunny/crossref_metadata_2025 huggingface dataset:
Eocene flower visitation of European Diptera and their potential pollinator role
Authors: Geier Christian , Bouchal Johannes Martin , Ulrich Silvia , Uhl Dieter , Wedmann Sonja , Wappler Torsten , Grimsson Fridgeir
Published: March 2024

Pollination by insects, including flies, is commonly a mutualistic interaction, in which both the plant and the insect benefit. Compared to other groups of pollinators or flower visitors relatively little is known about flower visitation by flies (Diptera) during most of the Cenozoic. Until now, the fossil record has provided only a few reliable fossils where flies are preserved with in situ or adhered pollen from flowers they visited before death and fossilization. Here, we report preliminary results from an ongoing study on flower-dipteran interactions during the middle Eocene of Central Europe. We screened 220 Diptera (19 with pollen) from the Middle Eocene of Messel and 20 Diptera (one with pollen) from the Middle Eocene of Eckfeld. The flies were screened for in situ pollen in their digestive system and adhering pollen present on various parts of their exoskeleton (head, thorax, abdomen, leg, etc.). From Messel, we studied, among other Arthropoda, 65 Brachycera (=flies; eleven with pollen) and 93 Nematocera (incl. gnats and midges; six with pollen). Out of the 20 pollen-bearing specimens, one had both gut content and adhering pollen, seven had only gut content pollen, and twelve had only adhering pollen. Each fly had between one and seven different pollen types. The number of pollen types found on the flies suggests both oligo- and polylectic feeding behaviour depending on the taxon. Only a few of the same pollen types (four pollen types) were found on different flies. In total we discovered 19 different pollen types on all the fossil fly specimens. The pollen represents, among others, Araliaceae, Cornaceae, Hamamelidaceae, Juglandaceae, Lythraceae (Decodon), Oleaceae, Rutaceae, Sapotaceae, and Vitaceae (Parthenocissus). Surprisingly, four flies carried Juglandaceae pollen on their exterior, but today, this family is mainly wind-pollinated. The amount of in situ pollen discovered was, in most cases, filling the whole digestive system of the flies, suggesting long and active feeding from anthers of flowers. About half the flies bearing adhered pollen had considerable amounts on their exterior, suggesting they could be potential pollinators of the plants they visited, especially Araliaceae, Hamamelidaceae, and Sapotaceae.
Transboundary Air Quality Challenges in South Asia: A Comprehensive Analysis of Climatological Circulation Patterns and Implications for Bangladesh and Beyond
Authors: Mahmood Diya , Khan Firoz , Ahmed Deen , Rahman Shahanaj , Motalib Abdul , Moniruzzaman Mohammad , Ali Shaikh Aftab , Huda Nurul , Xiang Jing
Published: March 2024

This article delves into the climatological circulation patterns in South Asia, specifically honing in on the Indo-Gangetic Plain (IGP) region, and examines their repercussions on air quality and public health in Bangladesh. The investigation scrutinizes the seasonal dynamics of air masses, aerosol plumes, wind components, boundary layer conditions, ground-level air particles, and gases. Employing reanalysis data from ERA5 and visualizing it with the Grid Analysis and Display System (GrADS) between 2015 and 2021, the study corroborates its findings using ground-level observation data from various sites in Bangladesh. Uncovering that Bangladesh faces deteriorating air quality in winter due to transboundary influences from the IGP and the far western regions, the study notes elevated aerosol and gas levels at the northern Rangpur site compared to Dhaka, signifying transboundary air pollution impact. Conversely, clean air from the Bay of Bengal sweeps over Bangladesh during the South Asian monsoon, benefiting the entire western IGP region. The research identifies local processes contributing to winter aerosol levels in Bangladesh, with transboundary pollution, notably from coal and post-monsoon crop burning in India, exacerbating air pollution. Utilizing statistical generalized additive modeling (GAM), the study discerns relationships between air pollutants and meteorological variables. It reveals the influence of CO and SO2 emissions on winter PM 2.5 levels, while wind speed and the planetary boundary layer (PBL) show a negative correlation with PM 2.5 concentrations during the monsoon and post-monsoon seasons. The findings underscore the significant impact of biomass burning and the PBL on Bangladesh's air quality. Considering Bangladesh and the Maldives as particularly susceptible to poor air quality consequences, the study emphasizes the urgency of targeted interventions and adaptive strategies in these regions. Notably, it pinpoints hotspots in the North Indian, Pakistani, and Afghan regions, introducing a geopolitical dimension to the study. This underscores the transboundary nature of the issue, stressing the need for cross-border collaboration in finding solutions. Additionally, the study connects seasonal circulation patterns and air pollution sources to implications for air quality and public health in Bangladesh, proposing mitigation strategies. It suggests leveraging the Malé Declaration (MALE) as a catalyst for collaborative efforts in mitigating transboundary air pollution across South Asia. In summary, the research not only contributes insights into Bangladesh's air quality but extends its implications regionally, laying the groundwork for a comprehensive and collaborative approach to address shared air quality and public health challenges in South Asia.
Molecular-level insight into the organic aerosol formation under the interactions between VOCs and inorganic sulfate and NOx
Authors: Wang Yujue , Guo Song , Wu Zhijun , Zhou Yang , Yu Jianzhen , Hu Min , Gao Huiwang
Published: March 2024

Field observations were conducted in various environments, from polluted urban to clean marine atmospheres, to understand the organic aerosol formation under the influence of inorganic sulfate and NOx. Molecular compositions of organic aerosols were analyzed using an ultrahigh-resolution mass spectrometer. The S-containing and N-containing organics are important fractions for SOA accumulation during pollution episodes or under high humidity conditions. To further investigate their formation pathways, organosulfates (OSs) and nitro-aromatics (NACs) were quantified using HPLC-MS.Particulate OSs were formed via acid-catalyzed aqueous-phase reactions in the presence of sulfate aerosols. When sulfate dominated the accumulation of secondary inorganic aerosols, OS formation would be obviously promoted as the increasing of acidic sulfate aerosols, aerosol liquid water and acidity. The formation of biogenic OSs and their notable roles in organic aerosols calls for elaboration in regions with substantial biogenic-anthropogenic interactions and over marine areas with high biological activity and high SST.Anthropogenic NOx influences the SOA formation via nighttime NO3-initiated oxidation of monoterpene, as well as involving in the oxidation of toluene and benzene. As the increasing of NOx concentration levels, the formation of nitrooxy-OSs or NACs shift from NOx-limited to NOx-excess regimes. Transported anthropogenic NOx from continental outflows would obviously enhance the nitrooxy-OSs formation in organic aerosols over marginal seas.
Enhancing 3D Feature-based Landslide Monitoring Efficiency by Integrating Contour Lines in Laser Scanner Point Clouds
Authors: Hosseini Kourosh , Hummelsberger Jakob , Czerwonka-Schröder Daniel , Holst Christoph
Published: March 2024

Landslides are a pervasive natural hazard with significant societal and environmental impacts. In addressing the critical need for accurate landslide detection and monitoring, our previous research introduced a feature-based monitoring method enhanced by histogram analyses, straddling a middle ground between point-based and point cloud-based methods. This paper expands upon that foundation, introducing an innovative contour line extraction technique from various epochs to precisely identify areas prone to deformation. This refined focus diverges from conventional methodologies that analyze entire point clouds. By applying on regions where contour lines do not match, indicating potential ground movement, we significantly elevate the efficiency and precision of our feature-based monitoring system. One of the principal challenges of feature-based monitoring is managing a substantial number of outliers. Our prior research tackled this issue effectively by integrating feature tracking with histogram analysis, thereby filtering these outliers from the final results. However, the process of extracting features from each patch and matching them with corresponding patches from different epochs was time-intensive. The incorporation of contour line extraction into our workflow, using high-resolution laser scanner data, allows for a more focused and efficient analysis. We can now identify and analyze areas of landscape alteration with greater accuracy. This approach limits the application of feature tracking and histogram analysis to these critical areas, thus streamlining the process and significantly reducing computational demands. This focused methodology not only accelerates data processing but also enhances the accuracy of landslide predictions. Our findings indicate a substantial improvement in the efficiency of landslide monitoring methods. This methodology represents a promising advancement in geospatial analysis, particularly for environmental monitoring and risk management in regions susceptible to landslides. This research contributes to the ongoing efforts to develop more effective, efficient, and accurate approaches to landslide monitoring, ultimately aiding in better informed and timely decision-making processes for hazard mitigation and risk management.
Analysis of the interactions between coastal morphodynamic processes and Beach Litter distribution. 
Authors: Rizzo Angela , Sozio Angelo , Anfuso Giorgio , La Salandra Marco , Sasso Corrado
Published: March 2024

Beach litter (BL) poses a constant threat to coastal areas and related ecosystems. Standard monitoring techniques used so far for the identification and classification of BL items consist of in situ visual surveys, which are time-consuming and only allow to cover limited coastal stretches. Recently, innovative and multi-disciplinary approaches have attempted to limit these logistic and practical issues. In this context, a growing number of studies are exploiting the use of aero-photogrammetric surveys, coupled with GIS software post-processing tools, for the monitoring of BL-related pollution. To this purpose, Unmanned Aerial Vehicles (UAVs) are often used to acquire images that can be used to evaluate the BL items' density and the relationships between coastal morphodynamic processes and BL distribution along the beach profile. In this study, carried out in the frame of the RETURN Extended Partnership and RiPARTI Project, the results obtained from a monitoring survey carried out along the Torre Guaceto beach (Apulia region, Italy) are shown. In particular, aero-photogrammetric flights were conducted to obtain RGB georeferenced orthomosaics on which manual image screening and morphodynamic analysis were performed to define the recent shoreline evolution and analyze the potential influence of coastal processes in the dispersion and accumulation of BL along the beach profile. The visual screening process was carried out in QGIS software and 382 BL items were identified and categorized. Artificial polymers/plastic (88%) turned out to be the most frequently represented object, followed by glass and textiles (3.4%). Coastal evolution trends were estimated using a specific GIS tool. Results highlighted a general retreat trend of the shoreline, with erosion rates ranging from 1.4 m/yr to 0.18 m/yr. The limit of the fixed vegetation has also been affected by recent retreat processes, up to 3 m. The zone between the embryo dune and the foredune limit, corresponding to the inner section of the investigated beach, gathered the highest density of BL items (1.24 items/m2). This zone is relatively far from marine or aeolic processes along the shoreline so, objects tend to lay for a longer period of time. These can constitute accretion cores for small embryo dunes that, in turn, will tend to increase the risk of burial for BL items. In conclusion, this study highlights that the exploitation of UAV systems facilitates the monitoring of wide coastal sectors and the analysis of beach morphodynamic trends, supporting the identification of hotspot areas for BL accumulation and the definition and planning of tailored clean-up activities.
Global surface ocean temperature anomalies in 2023 and their climate context
Authors: Menary Matthew , Hermanson Leon
Published: March 2024

Around 3 billion people rely on the ocean for their livelihoods, with around 10% of the world’s population directly relying on fishing. As human-driven climate change causes the world to warm, the ocean and the ecosystems within are increasingly susceptible to heatwave events that can have severe consequences. Such marine heatwaves (MHWs) can last from several days to a year and result in the destruction of ocean habitats and the diminution or relocation of fish species, with knock-on effects for coastal communities. The frequency of MHWs has doubled since 1982 and they are likely to continue to increase in frequency, intensity, and duration. However, the link between MHWs and modes of climate variability remains uncertain. Here, we investigate to what extent maps of temperature anomalies in 2023 can be attributed to large-scale climate modes with centres of action in the Atlantic, North Pacific, and tropical Pacific. Specifically, we regress global sea surface temperatures on to indices of Atlantic Multidecadal Variability (AMV), the 2nd EOF of North Pacific variability (commonly linked to MHWs), and El Nino/Southern Oscillation (ENSO, which strongly correlates with the 1st EOF of North Pacific variability). We find that around 30% of the variance in global, annual sea surface temperature anomalies can be explained by a linear combination of these indices. Since 2012, the combination of these indices has been unprecedented, associated with anomalous warming (on top of the global trend) throughout the northern hemisphere. As such, climate variability (which may include a forced component) is currently providing an unusually high baseline for further MHW events. Further work will aim to use decadal prediction models to investigate the predicted evolution of these indices over the coming years.
South Pacific hydroclimate response to multi-decadal modes of variability in the IGCM4 climate model
Authors: Skinner Daniel , Joshi Manoj , Matthews Adrian , Osborn Timothy
Published: March 2024

The South Pacific Convergence Zone (SPCZ) dominates the climate dynamics of the tropical South Pacific, significantly influencing global climate dynamics. The magnitude, slope, and spatial extent of the SPCZ's precipitation pattern, are responsive to changes in both trade winds and the Southern Hemisphere subtropical jet. These changes are, in turn, driven by modes such as the MJO and ENSO. Whilst the drivers of SPCZ variability on subseasonal to interannual timescales are well-documented, understanding of its variability over multi-decadal to millennial timescales remains limited.Quantitative reconstructions of South Pacific hydroclimate reveal rapid, and as yet unexplained, changes in the SPCZ over recent millennia that do not align with large-scale climate forcing. This study proposes that large-scale multi-decadal modes of variability may play a crucial role in driving SPCZ variability.Using an Intermediate General Circulation Model (IGCM4), we investigate the SPCZ's response to sea surface temperature (SST) forcing corresponding to the Atlantic Multi-decadal Variability (AMV) and Interdecadal Pacific Oscillation (IPO). Applying monthly varying SST anomalies at a range of magnitudes and in different combinations, we assess the linearity of the SPCZ response to these multi-decadal modes. Additionally, we explore the pathways associated with each response by applying SST anomalies both globally and within the respective basin.This research aims to enhance our understanding of the interaction between the SPCZ and multi-decadal modes of variability, providing insights into past changes in the proxy record and contributing to the development of future SPCZ projections.
Picoseismic response of hectometer-scale fracture systems to stimulation under the Swiss Alps, in the Bedretto Underground Laboratory
Authors: Obermann Anne , Rosskopf Martina , Durand Virginie , Plenkers Katrin , Bröker Kai , Gholizadeh Doonechaly Nima
Published: March 2024

We performed a series of hydraulic stimulations at 1.1 km depth in the Bedretto underground laboratory in the Swiss Alps. The goal was to achieve an unprecedented detailed and profound understanding of hydromechanical and seismic processes during hydraulic reservoir development with a dense multi-sensor monitoring network. With our seismic network that includes various sensor types with different sensitivities, we succeeded in characterizing induced seismicity down to the pico-seismicity level (Mw
Application of micro-CT to resolve textural properties and assess primary sedimentary structures of deep-marine sandstones
Authors: Degenhart Gerald , Cornard Pauline , Tropper Peter , Moernaut Jasper , Strasser Michael
Published: March 2024

Over the past decade, there has been growing interest in the sedimentological community to use micro X-ray computed tomography to analyse microfacies in sediments and bedforms. However, little attention has been paid to the application of micro-computed tomography in lithified deposits, even though this can allow their texture to be characterised in three dimensions, providing key information about sedimentary and bedform micro structures. A novel application of micro-computed tomography in lithified sediment-gravity flow deposits is presented with the objective of characterising their internal 3D sedimentary structures. This technique is applied to three deep-marine sandstones showing different compositional properties: Cretaceous Gosau Group (Austria), Eocene Hecho Group (Spain) and the Oligocene Annot Formation (France). From micro-computed tomography data, the size of particles and their distribution throughout the sample is reconstructed in 3D, permitting a better visualisation of sedimentary textures. Particle distributions computed from micro-computed tomography are similar to those computed from thin section image analysis, corroborating the reliability of the micro-computed tomography to evaluate grain-size trends. Micro-computed tomography is complemented with micro-X-ray fluorescence and thin section petrographic analyses. In cases where mineral composition or grain size are homogeneous or matrix and grains have similar mineral composition, sedimentary structures do not appear visible from micro-X-ray fluorescence or thin section analyses. By separating particles based on their computed tomography density, it is possible to isolate the coarsest fraction, highlighting the sedimentary structures. This study demonstrates (i) the potential of micro-computed tomography in analyses of sedimentary structures from outcrop data and (ii) the importance of the mineralogical composition and degree of grain sorting in assessing the origin of structureless deposits and bedforms. Considering the importance of visualising sedimentary structures when interpreting depositional processes, micro-computed tomography is a new and reliable tool to assess the physical properties of sandstones and to analyse their internal 3D sedimentary structures.
Dynamics of alpine treeline in the High Tatra Mts., Slovakia
Authors: Varsova Svetlana , Lukasova Veronika , Onderka Milan , Bilcik Dusan
Published: March 2024

Global warming affects the climatic conditions in the mountain environments. The climate of the alpine treeline ecotone (ATE) in the High Tatra Mts. is represented by unique conventional long-term climatological series from Skalnaté Pleso Observatory (49°11'21.9” N; 20°14'02.7” E). When considering the two last normal periods (1961-1990 and 1991-2020), the average air temperature in ATE increased by  1.1 °C. In this work, we analysed the altitudinal shift of the boundary 6°C isotherm, which represents the minimum temperature requirements for the growth and reproduction of tree vegetation. To determine the altitude of the cold treeline limit, i.e. upper limit of ATE, we used climate data from Skalnaté Pleso Observatory (1,778 m a.s.l.) and the near top meteorological station Lomnicky štít (2,634 m a.s.l.).  We found that over the analysed period 1951-2020, the limiting isotherm moved upwards from the level of 1,950 m a.s.l. to 2,200 m a.s.l.. Preliminary field monitoring and mapping indicated the colonisation of the dominant subalpine vascular species Pinus mugo Tura (mountain pine) into alpine summits. We identified young individuals or small groups of mountain pine at altitudes between 2,000-2,200 m a.s.l., which is consistent with the assumption of vertical extension of low tree vegetation due to positive changes in ambient thermal conditions. The warming of the alpine tree line ecotone may lead to a gradual reduction and eventual disappearance of montane species due to their strict ecological specialisation. The replacement of the populations of cold-adapted alpine species by those profiting from the warmer climate may cause a decline in the ecosystem's biodiversity. Therefore, further research will be focused on verification of the climate-related shift of the boundary line for the growth of mountain pine at the ATE zone in the highest mountain range of the central-eastern region of Europe.
Towards Carbon Dioxide imaging using Fabry-Pérot interferometer correlation spectroscopy
Authors: Sindram Moritz , Kuhn Jonas , Kleinschek Ralph , Fuchs Christopher , Knapp Marvin , Löw Benedikt , Nies Alexander , Schmitt Tobias , Butz André
Published: March 2024

Carbon dioxide (CO2) emissions are the major driver of anthropogenic climate change. While strong point sources contribute significantly to overall emissions, their source strength is not always well quantified by bottom-up estimates or in situ measurements. Passive remote sensing of CO2 emissions could provide a simple tool to substantially refine source strength estimates. However, current approaches from ground-based to space-borne platforms only suit exceptionally strong emitters.We propose a ground-based CO2 imaging technique based on Fabry-Perot interferometer (FPI) correlation spectroscopy. The free spectral range (FSR) of an FPI is matched to the spectral separation of individual rovibrational absorption lines of the CO2 1.57 µm absorption band. This allows to compare the radiance of sky-scattered sunlight between “online” and “offline” wavelengths, i.e., the FPI transmission spectrum correlating and anti-correlating with the CO2 absorption lines, respectively. The advantage of a high FPI light throughput enables imaging measurements of the CO2 column density with a resolving power of 18,000.Instrument simulations based on available optics suggest an integration time of approximately 10 seconds to record a CO2 plume image with 300 by 300 pixels of a medium-sized power plant (7 Mt CO2/yr). This is about two orders of magnitude faster compared to grating-based imaging spectrometers. For recording the emission plume of a passively degassing volcano at the same spatial resolution integration times are on the order of ten minutes. Additionally, we present ongoing work on developing a prototype instrument to validate the feasibility of this CO2 imaging technique.
Impact of new Earth’s time-variable gravity field models on orbits of altimetry satellites
Authors: Rudenko Sergei , Dettmering Denise , Bloßfeld Mathis , Zeitlhöfler Julian
Published: March 2024

Gravitational forces are the major forces acting on near-Earth orbiting (e.g., altimetry) satellites. Recently published Earth’s gravity field models used within the satellite precise orbit determination (POD) comprise observations of GRACE (Gravity Recovery And Climate Experiment) and GRACE-FO (GRACE-Follow-On), gravity field satellite missions between 2002 until 2017 and since 2018, respectively. In this presentation, we perform a review of selected Earth’s time-variable gravity field models developed in the past ten years (2014-2023). We analyze also the POD results obtained for selected altimetry satellites, namely, TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3 at the time interval from 1992 to 2023 using various Earth’s gravity field models. A special focus is put on the CNES/GRGS mean gravity field models of releases 2 to 5, including the latest CNES_GRGS.RL05MF_COMBINED_GRACE_SLR_DORIS model. The impact of these models is assessed for different orbit parameters as well as the root-mean-square and mean values of Satellite Laser Ranging observation residuals and orbit differences. Furthermore, the impact of these models on altimetry (single- and multi-satellite) sea surface height crossover differences is investigated. From these crossover differences, radial errors and geographically-correlated mean errors are derived and analyzed. The results are used to conclude on the accuracy of current Earth’s time-variable gravity field models when used for the POD of altimetry satellites.
Nature based Solutions and combined techniques in the immediate vicinity of infrastructure and residential areas -  Case studies of steep bank stabilizations in the Garonne water catchment area in France realized between 1999 and 2022
Authors: Peklo Klaus
Published: March 2024

Our motivation is to explain how severe bank slides, such as those following natural disasters, can be sustainably reintegrated into the river ecosystem in a modern, contemporary manner through the application of NbS and combined techniques. Our purpose is to explain the needs of an integrated engineering approach to find out the causes of streambank slides before works start. We point out the workflow of NbS reconstruction process by determining an efficient analysing stage, a construction stage and a monitoring stage. We show three realized examples of steep bank reintegration situated in high flow regime. Our conclusions show that reintegration into the river landscape of violent bank slides near residential areas and infrastructure with NbS techniques is feasible. The prerequisites, however, are a sufficient root cause analysis by an integrated engineering approach, and good training and experience of the hired construction companies during construction stage. In addition, clients need to throw out some of their old ideas of exclusively mineral and similar attachment techniques. This presentation serves as a demonstration of the potential of sustainable NbS steep bank revegetation for infrastructure protection, based on geotechnical analysis using examples realized in France between 1999 and 2022.
Intraseasonal Oscillation of Land Surface Moisture and  its role in the maintenance of land CTCZ during the active  phases of the Indian Summer Monsoon
Authors: Gautam Pratibha , Chattopadhyay Rajib , Martin Gill , Joseph Susmitha , Sahai Atul kumar
Published: March 2024

This study focuses on the soil moisture characteristics and its role in supporting the continental tropical convergence zone (CTCZ) during the active phase of the monsoon. Like rainfall, land surface parameters (soil moisture and evaporation) also show intraseasonal oscillation. Furthermore, the sub-seasonal and seasonal features of soil moisture are different from each other. During the summer monsoon season, the maximum soil moisture is found over western coastal regions, central parts of India, and the northeastern Indian subcontinent. However, during active phases of the monsoon (i.e., on sub-seasonal timescales), the maximum positive soil moisture anomaly was found in northern India. Land surface characteristics (soil moisture) also play a pre-conditioning role during active phases of the monsoon over the monsoon core zone of India. When it is further divided into two boxes, the north monsoon core zone and the south monsoon core zone, it is found that the preconditioning depends on that region's soil type and climate classification. Also, we calculate the moist static energy (MSE) budget during the monsoon phases to show how soil moisture feedback affects the boundary layer MSE and rainfall. A similar analysis is applied to the model run, but it cannot show the realistic preconditioning role of soil moisture and its feedback on the rainfall as in observations. We conclude that to get proper feedback between soil moisture and precipitation during the active phase of the monsoon in the model, the pre-conditioning of soil moisture should be realistic.
Variations in sensible heat flux of High-Asia and their relationship with China's summer precipitation
Authors: Yao Nan , Ma Yaoming , Li Xueying , Peng Jian
Published: March 2024

The High-Asia (HA), which includes the Tibetan Plateau (TP), Iranian Plateau (IP) and Mongolian Plateau (MP), is experiencing a warming rate that is twice the global average. The increasing temperature is causing significant changes in thermal conditions across the HA and surrounding regions, which may further affect China's summer precipitation. This study used datasets from the ERA5-Land reanalysis and the high-resolution China Meteorological Forcing Data to investigate variations in SH over three plateaus of HA, and to explore the relationship between these variations and changes in China's summer precipitation. The results indicate that variations in summer SH of the HA are the largest, making them the primary contributor to the annual mean values. The summer SH over TP exhibited a decreasing trend from 1979 to 2021 (-0.47 W m-2 decadal-1, p
The U.S. Greenhouse Gas Center: Extending Accessible and Integrated GHG Information from U.S. Government and Non-Public Sources to meet user needs
Authors: Combley Shanna , Kavvada Argyro , Ott Lesley , Bowman Kevin , Maskey Manil , Green Robert , Irving William , Weitz Melissa , Grubisic Vanda , Stein Ariel , Whetstone James , Eldering Annmarie , McDuffie Erin , Kashdan Alix
Published: March 2024

The newly established United States Greenhouse Gas Center (U.S. GHG Center) is a multi-agency partnership between the National Aeronautics and Space Administration (NASA), the Environmental Protection Agency (EPA), the National Oceanic and Atmospheric Administration (NOAA) and the National Institute of Standards and Technology (NIST) that aims to accelerate the production and delivery of actionable, trusted greenhouse gas (GHG) information from the federal government and non-public sector to a variety of users through a coordinated data system, reflecting transparency and open source science principles in both data and methods. The US GHG Center acts as an enabler of collaboration with networks of interagency, international, intergovernmental and private sector partners to increase confidence in setting, assessing, and meeting climate change mitigation goals, with a preliminary focus on carbon dioxide and methane. The US GHG Center is also a critical element in the implementation of the “National Strategy to Advance an Integrated US Greenhouse Gas Measurement, Monitoring, and Information System”.  Initial focus areas include 1) Gridded anthropogenic greenhouse gas emissions, 2) Natural sources and sinks, and 3) New Observations for tracking large emission events. The US GHG Center web portal includes a prototype data catalogue, exploratory data analysis capabilities, a collaborative science environment for data analysis and exploration, as well as an interactive visual interface for storytelling. Examples of products currently available on the GHG Center portal include methane and carbon dioxide concentration anomalies and emissions from airborne and space-based instruments, including from NASA’s Earth Surface Mineral Dust Source Investigation (EMIT) imaging spectrometer in orbit on the International Space Station, EPA’s gridded U.S. anthropogenic methane greenhouse gas inventory data, gridding methodologies and visualizations, NOAA’s Observation Package (ObsPack) data products that bring together atmospheric greenhouse gas observations from a variety of sampling platforms, as well as multi-model land flux and ecosystem exchange estimates. 
Interplay of photosynthesis and biophysical potential to model tree growth
Authors: Cabon Antoine , Ameztegui Aitor , Anderegg William R L , Martínez-Vilalta Jordi , De Cáceres Miquel
Published: March 2024

Tree growth is a key uncertainty in projections of forest productivity and the global carbon cycle. While global vegetation models commonly represent tree growth as a carbon assimilation (source)-driven process, accumulating evidence points toward widespread non-photosynthetic (sink) limitations. Notably, growth biophysical potential, defined as the upper-limit to tree growth imposed by temperature and turgor constraints on cell division, has been suggested to be a potent driver of observed decoupling between tree growth and photosynthesis. Understanding the interplay between biophysical potential and photosynthesis and how to accommodate it parsimoniously in models remains a challenge.Here, we use a soil-plant-atmosphere continuum model together with a regional network of forest structure and annual, radial tree growth observations extending over three decades to simulate tree photosynthesis and biophysical potential along an aridity gradient and across five tree species in NE Spain. We then apply a linear modelling framework to quantify the relative importance of photosynthesis, biophysical potential and their interactions to predict annual tree growth along the aridity gradient.Overall similar relative importance of photosynthesis and biophysical potential was underlain by strong variations with climate, photosynthesis being more relevant at wet sites and biophysical potential at dry sites. Observed spatial and temporal trends further suggested that tree growth is primarily limited by biophysical potential under dry conditions and that disregarding it could lead to underestimating tree growth decline with increased aridity under climate change.Our results support the idea that biophysical potential is an important component of sink limitations to tree radial growth. Its representation in vegetation models could accommodate spatially and temporally dynamic source-sink limitations on tree growth.
Estimating leaf area organization (LAO) using Sentinel-2 and airborne LiDAR to assess silvicultural thinning effects on canopy structure in dryland forests 
Authors: Paz-Kagan Tarin , (Vladislav) Dubinin Moshe , Yakir Dan , Osem Yagil
Published: March 2024

The leaf area organization (LAO) approach uses a set of metrics describing the spatiotemporal organization of the forest leaf surface interface. It is useful for reflecting the complexity of canopy structure in assessing forest functions, such as evapotranspiration and primary productivity. We developed the estimation of LAO parameters, including LAIEcosystem (the one-sided leaf area of the entire forest vegetation, per unit ground area), its separation into forest strata (LAIOverstory, LAIUnderstory), vertical arrangement (LAI profile), and forest growth status with respect to site potential (growing space occupancy: GSO=LAIEcosystem/LAImax) using the Sentinel-2 satellite and an airborne LiDAR system (LiDAR-ALS). The LAO parameters were examined during 2017–2022 in two dryland conifer forests along a climatic aridity gradient from arid (Yatir Forest) to semi-arid (Kedoshim Forest) and across silvicultural thinning treatments (clear-cut, 100, 200, 300 trees ha-1 and non-thinned control in 70×70 m plots). We found significant correlations across the thinning treatments between ground-based optical measurements and both the estimations of LAIEcosystem based on Sentinel-2 data of 11 vegetation indices and one texture parameter (R2=0.73–0.87), and the estimations of LAIOverstory, LAIUnderstory, and LAIEcosystem, based on the LiDAR-ALS (R2=0.82–0.90). Using the LiDAR-ALS estimations, we found that 10 years after thinning, LAIEcosystem decreased with thinning intensity in both sites but was higher in the wetter Kedoshim site (0.45–1.27 m2 m-2 vs. 0.04–0.31 m2 m-2 in the arid Yatir forest). However, the overall decrease in LAIEcosystem reflected the combined effects of a reduction of LAIOverstory, in both sites and an increase in LAIUnderstory in the wetter site but not in the dry site (increasing by 0.08–0.86 m2 m-2). Using Sentinel-2 to assess the inter-annual dynamics of forest structure in the 8–13 years since thinning indicated that in the wetter Kedoshim site, LAIEcosystem significantly correlated with rainfall (R2=0.75–0.85), in all thinning treatments, with an overall increasing trend in the more intense thinning treatments only. The GSO showed a positive temporal trend in the clear-cut (3–15%) and the more intense thinning treatments in both forest sites (45–51% in the wetter site and 30–34% in the arid site). Our research uses a novel approach to demonstrate complex, ecosystem-scale, long-term structural responses to thinning in dryland forests. Such effects of thinning treatment should be considered for forest management for facing climate change in these forests.
Automatic pockmark detection in the Norwegian Channel 
Authors: Ottesen Dag , Diesing Markus
Published: March 2024

Pockmarks are widely distributed in areas with fine-grained layered sediments. We utilised a large multibeam bathymetric dataset covering an area of c. 15,000 km2 of the Norwegian Channel (NC), the western slope and adjacent shelf outside western Norway. Pockmarks were extracted from the bathymetry data with two approaches: by identifying local minima in the bathymetry and by mapping landform types based on geomorphons. While the former approach yielded a point dataset indicating local minimum depths, the latter approach allowed to outline potential pockmarks as polygons based on the landform types of pits and valleys. To increase the reliability of the classification, only pockmark polygons that contained at least one local minimum were subsequently retained. This mainly removed artefacts at the edges of the classified area. Likewise, only those local minima that fell inside a pockmark polygon were retained. Finally, a limited number (
Monitoring 4D landslide displacement using very high resolution Pléiades satellite remote sensing.Case study of the La Valette landslide, French Alps
Authors: Fu Sheng , de Jong Steven M. , Nijland Wiebe , Gravey Mathieu , Kraaijenbrink Philip , de Haas Tjalling
Published: March 2024

Slow-moving landslides may pose a substantial threat to communities and infrastructure, with annual creeping distances ranging from a few mm to 100 m. To protect local communities from the landslide motion, landslide displacement monitoring is necessary. However, traditional field investigations are time- and labor-consuming, which may limit the understanding of the landslide evolution and thereby mitigation. Here we propose a 4D landslide displacement framework using optical very high resolution (0.5m) Pléiades satellite constellation imagery. We use our method to monitor the annual movement of the ‘La Valette’ landslide, southern French Alps, between 2012 and 2022. During this period, the landslide moved most actively during the years 2012 and 2013, with average 3D displacement rates of 1.22 and 0.89 cm / day, respectively. Furthermore, we found a decelerating trend in movement rate from 2012 to 2022, which we attribute to warmer weather, decreasing precipitation rates, drier air conditions, and the implementation of a drainage installation. Our study demonstrates the great potential of very-high resolution satellite imagery for near-real time monitoring of 4D landslide displacement, which may benefit research and may contribute to the mitigation of damage and fatalities of slow-moving landslides.
Changes in the world of geological mapping
Authors: Pubellier Manuel , Sautter Benjamin , Song Yang , Wang Chengshan
Published: March 2024

Geological information is crucial for the civil society via public authorities, and is produced by scientists from academia and national geological surveys. This information is useful for better use of resources (water, energy, and mineral), adaptation to the climate change, and of course natural hazards. In the meantime, the Earth has become smaller, information technology has improved considerably, and allows to cross-analyze data. If communication is made easier for research and dissemination of the geological knowledge, formats have become the key for scientific exchanges.The Commission for the Geological Map of the World (CGMW) was created for this exact purpose in the early 20th century in an attempt to bring scientists together, but it took a century to acknowledge that we are more than ever accountable for the preservation of the Earth, and forced to understand the importance of the linkage between geology and global change. As early as 1964, the UNESCO bi-annual program encouraged specialists to develop and use a uniform terminology and classification for the different Earth sciences. CGMW is a rank A UNESCO organization and is affiliated to IUGS and IUGG. The spearheading product of CGMW had been the Geological Map of the World at 1:35M scale for decades, and the opportunity of elaborating a large Geological Map of the World at scale 1:5M – (World5M), was proposed in 2018, as an IUGS Big Science Program DDE (Deep time Digital Earth).This program, co-funded by the Chinese Academy of Geological Sciences (CAGS), aimed at harmonizing global digital Earth data and securing compatible and interoperable databases, and was rapidly considered as essential for international maps, which can be accessible by a data platform aligned with the vision and mission of the IUGS Big Science Program. This project, (1) integrates at a scale 1:5M the geological maps of continents and oceans which have been produced under supervision of the CGMW, (2) established the legend system and adequate architecture for the map database, and (3) constructed a new seamless and digital geological map of the world at the scale 1:5M. In reality, the geology presented in each small scale continental geological map, differs drastically in terms of stratigraphic cuts and trans-boundary connections of structural continuities. In addition, the databases were constructed originally in different ways with contrasting semantics and data standards, thus requiring a robust collaborative work in Geology and Geomatics. Among the outcomes of the project, is the possibility to integrate selected geological features over a large coverage with a similar resolution. This has been already used in new mapping syntheses, making them more informative.
Meteorological and Soil Moisture Measurements in Mount Kenya Region at Various Scales
Authors: Musyimi Peter K. , Székely Balázs , Kamiri Hellen W. , Ouna Tom , Weidinger Tamás
Published: March 2024

The optimal solution for solving many uncertainties associated with weather and climate data is accurate field measurement. This enhances various climate services that can be offered to different sectoral case studies and solve societal weather-related challenges by ensuring the obstacles are overcome amicably, for instance, climate adaptation barriers in the face of climate variability. The main goal of our study was to make long-term meteorological measurements in Mount Kenya region rainforest biome at an elevation of 1998 m above sea level (Karatina University weather station) and 3055 m above sea level (Mount Kenya field station) used at various scales from 2022. We are using Temperature-Moisture-Sensor (TMS) burial (1 m) and TMS Long (45 cm) soil sensors as well as temperature/relative humidity data loggers. These devices provide us with crucial data and reshape field measurement campaigns in data-scarce regions of Kenya. The soil moisture sensors also measure soil temperature, surface, and air temperature. The soil moisture data and temperature at various scales is acquired at an interval of 10 minutes while the data logger records data at an interval of 30 minutes.  Another key goal was to acquire soil moisture data at tropical rainforest biome which is scarce as well as relative humidity and temperature. The objectives of the study are to analyze reference evapotranspiration and estimation of real evapotranspiration in humid Mount Kenya climatic region, Nyeri County; compare climate parameters in two different elevations; to understand microclimatic changes associated with varying elevations and ensure data quality control in analysis by checking uncertainties and sensitivities associated with ERA5 reanalysis, synoptic (GFS/ECMWF) and station datasets. Therefore, to narrow the gap between missing data, uncertainties, and quality control of data, meteorological field measurements cannot be misconstrued.Keywords: data loggers, field measurement, soil moisture, quality control, Kenya,
Utilising Terrestrial Laser Scanning (TLS) for urban tree structure characterization and its impact on modelled human thermal comfort
Authors: Daelman Todi , Verbeeck Hans , Vancoillie Frieke , Demuzere Matthias
Published: March 2024

Urban green infrastructure plays a pivotal role in climate regulation by offering various ecosystem services. One crucial metric in understanding human thermal exposure is the mean radiant temperature (Tmrt), which encompasses the spatial and temporal variations of radiation exposure. In the context of urban microclimate models such as SOLWEIG, the accurate characterization of urban trees is essential, whether incorporating existing trees or assessing the cooling effects of new greenery. Currently, urban tree structures are usually generalised in urban climate models due to the lack of detailed measurements and scientific knowledge about urban tree growth and functioning.

Various vegetation types exhibit distinct effects on the attenuation of direct shortwave radiation through shading. Variations in tree shading are influenced by the configuration, optical and structural properties of planted tree species. Leaf Area Index (LAI), tree height, and trunk height significantly determine shade patterns and solar attenuation. We use state-of-the-art Terrestrial Laser Scanning (TLS) techniques to parameterize these structural properties for the precise implementation of existing trees within urban microclimate models. This enhanced structural understanding of urban trees will facilitate the creation of more realistic tree models, allowing for a comprehensive assessment of their impact on human thermal comfort. 
SOLWEIG operates as a 2.5-dimensional model, where x and y coordinates and associated attributes (e.g. height, emissivity or reflectivity) are utilised for the calculation of Tmrt. Greenery such as trees and bushes are represented in separate Digital Elevation Models (DEMs). TLS allows for the highest degree of parameterisation of urban trees within the given raster environment. By conducting a sensitivity analysis on the modelled Tmrt, we explore the impact of tree and trunk height, canopy area and volume, and radiation transmissivity of vegetation.
The result of our sensitivity analysis provides valuable guidance on the TLS data collection of tree parameters essential for evaluating current cooling effects. Which in turn leads to the identification of tree species with significant cooling potential, and determining the size at which a tree substantially contributes to human thermal comfort. 