bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term Variability in Black Carbon Emissions Constrained by Gap-filled Absorption Aerosol Optical Depth and Associated Premature Mortality in China
Authors: Zhao Wenxin , Zhao Yu
Published: March 2024

Black carbon (BC) plays an important role in air quality, public health, and climate, while its long-term variations in emissions and health effect were insufficiently understood for China. Here, we present the spatiotemporal evolution of BC emissions and the associated premature mortality in China during 2000-2020 based on an integrated framework combining satellite observations, a machine learning technique, a “top-down” inversion approach, and an exposure-response model. We found that the “bottom-up” approach likely underestimated BC emissions, particularly in less developed western and remote areas. Pollution controls were estimated to reduce the annual BC emissions by 26% during 2010-2020, reversing the 8% growth during 2000-2010. BC emissions in the main coal-producing provinces declined by 2010 but rebounded afterwards. By contrast, provinces with higher economic and urbanization levels experienced emission growth (0.05-0.10 Mg/km2/yr) by 2010 and declined greatly (0.07-0.23 Mg/km2/yr) during 2010-2020. The national annual BC-associated premature mortality ranged between 733,910 (95% confidence interval: 676,790-800,250) and 937,980 cases (864,510-1,023,400) for different years. The changing BC emissions contributed 78,590 cases (72,520-85,600) growth within 2000-2005 and 133,360 (123,150-145,180) reduction within 2010-2015. Strategies differentiated by region are needed for further reducing BC emissions and its health and climate impacts.
Necessary core-mantle boundary heat flux pattern ingredients for observed latitudes of geomagnetic surface intensity minima
Authors: Terra Nova dos Santos Filipe , Amit Hagay
Published: March 2024

Thermal core-mantle interactions affect the convection pattern in the outer core and thus the morphology of the generated geomagnetic field.Correlations between longitudes of lowermost mantle seismic anomalies and prominent geomagnetic flux patches (normal and reversed) provideevidence for mantle control on the geodynamo (Gubbins et al., 2007, Terra-Nova et al., 2016). Analyses of geomagnetic field models and numerical dynamos with heterogeneous outer boundary heat flux inferred from lower mantle seismic anomalies demonstrated that the SAA longitudinal preferred position is also mantle controlled (Terra-Nova et al., 2019). In contrast, the present latitude of SAA was seldom reproduced. For fundamental understanging of the type of CMB heat flux pattern that may lead to large latitudes of surface intensity minima, we explore dynamo models with different single harmonic CMB heat flux patterns. Our goal is to unravel the core-mantle interaction that induces recurrent large latitude surface intensity minima. Here we show preliminary results from these simulations.
Hysteretic response of N2O reductase activity to soil pH variations after application of lime to an acidic agricultural soil
Authors: Rousset Camille , Ouerghi Iheb , Bizouard Florian , Brefort Henri , Ubertosi Marjorie , Arkoun Mustapha , Hénault Catherine
Published: March 2024

Nitrous oxide (N2O) contributes to increasing the greenhouse effect and is also involved in stratospheric ozone depletion. In soil and water, N2O reductase catalyses the reduction of N2O into the inert form N2 and is then considered as a key environmental enzyme. N2O reductase activity is known to be affected by acidic conditions (Samad et al. 2016) and the application of liming materials to acidic soils is now proposed as a solution for mitigating soil N2O emissions (Barton et al. 2013).During a one-year laboratory experiment, we studied the functioning of N2O reductase after the application of calcium carbonates to an acidic soil with initially a very low capacity to reduce N2O. The functioning of N2O reductase was characterised through anaerobic incubations using the acetylene inhibition technique combined with a logistic model to determine the main enzyme functioning characteristics (latency, maximal rate).Both changes in soil pH and soil capacity to reduce N2O were rapidly observed after the application of lime materials. The activity of N2O reductase was observed to be efficient throughout the experiment even when the soil had returned to initial acidic conditions, revealing a hysteretic response of N2O reductase to pH variations. Nevertheless, some signs of lower N2O reductase activity over time were observed mainly after 200 days of applying lime materials. Altogether, these results suggest that, in this soil condition, the beneficial impact of the application of liming materials on N2O emissions could last longer than this on soil pH.Keywords: Climate change mitigation · N2O reductase · Soil · pH · Lime application · Logistic modelling References:Barton, L. et al. (2013) Is liming soil a strategy for mitigating nitrous oxide emissions from semi-arid soils? Soil Biology and Biochemistry 62, doi: 10.1016/j.soilbio.2013.02.014Samad, M. S. et al. (2016) High-resolution denitrification kinetics in pasture soils link N2O emissions to pH, and denitrification to C mineralization. Plos One 11, doi: 10.1371/journal.pone.0151713   Acknowledgements: The authors gratefully acknowledge funding for the NatAdGES project from the “Investissement d’Avenir” program, ISITE-BFC project (contract ANR-15-IDEX-0003), the European Regional Development Fund (FEDER), the public investment bank (BPI France) and the CMI-Roullier.
River Flow Dynamics across Europe: Insights from continental to regional scales
Authors: Rudlang Julia , Hrachowitz Markus , V. M. do Nasciamento Thiago , van der Ent Ruud , Fenicia Fabrizio
Published: March 2024

River flow is affected by change in climate and land use. Today, we see many different magnitudes and directions of trends of change across European rivers with respect to streamflow, which affects water supply and hydrological extremes such as floods and droughts. Moreover, the drivers of change in streamflow and its temporal trends vary on multiple scales from local to regional to continental. In this study, we identify changes, trends and possible patterns of change in the hydrological response across the whole of Europe, as well as its underlying drivers. We do this by using multi-decadal streamflow data that was collected from more than 15000 European stream flow gauging stations in 39 European countries. This large-sample dataset, named EStreams and set to be published in 2024, provides valuable new perspectives on the hydrological response in Europe.In the analysis, similar catchments across Europe were clustered into groups, based on their hydrological response, as characterised by a wide range of hydrological signatures. This allowed to identify the different controls of hydrological response between the groups, such as climate, landscape and seasonal water balance.Furthermore, the high-resolution streamflow dataset used allowed for the opportunity to zoom in further and gave a meaningful look at the differences within the clustered groups. This ensured that it was possible to investigate the differences in hydrological responses that were primarily dictated by landscape characteristics, as within cluster catchments are assumed to have limited climate variability. Altogether, mapping out the different hydrological responses across Europe and the differences in hydrological response within nested sub-catchments gave a comprehensive identification and quantitative description of dominant landscape characteristics shaping the hydrological response within clusters of hydro-climatically distinct European regions.
Research on monitoring illegal air pollution using Scanning Lidar System
Authors: Kim Seong-min , Lee Dasom , Park Jeong-min , Lee Gahye , Kim Sangcheol , Jung Youndae , Yang Ilkwon , Kim Kwanchul
Published: March 2024

The Scanning Lidar System (SMART MK-II) analyzes light backscattered by particles in the air and calculates information about fine dust mass concentration with distance. fine dust concentration in real time and continuously was observed with a resolution of 30 m within a radius of 5 km using the Scanning Lidar System, and used to analyze air quality around industrial complexes. The observation location was the rooftop of the Tech University of Korea second campus building located in Siheung, Korea (37.32792, 126.6892). The optimal measurement site for the Scanning Lidar System was selected and the surrounding air pollution was observed horizontally by adjusting the height. This is a study to build advanced monitoring system that tracks illegal emission sources, focusing on areas(heat-map) with high concentrations of fine dust. Instead of randomly cracking down on illegally businesses and factories emissions source, the crackdown system was changed to focus on areas with high air quality concentration and high emissions by the advanced air monitoring system. The final goal of this study is to use the Scanning Lidar System visualization program to provide location notification services for areas with high fine dust concentration and suspicious air emission sources. It was used to crack down on illegal air emissions projects and inspect air pollution prevention facilities, and had the effect of reducing health damage caused by fine dust and improving air quality.Acknowledgement: This research was supported by a grant (2023-MOIS-20024324) of Ministry-Cooperation R&D Program of Disaster-Safety funded by Ministry of Interior and Safety (MOIS, Korea) and Metropolitan Environment Management Office in Gyeonggi-do Province, Korea.
Spatial variability of lacustrine groundwater discharge at basin scale
Authors: Sun Xiaoliang , Du Yao , Gan Yiqun
Published: March 2024

Lacustrine groundwater discharge (LGD) is a crucial component of water balance in lakes. However, research on the spatial variability of LGD on a large basin scale is scarce, and the factors controlling this variability are not well understood. In this study, we examined various lakes located throughout the CYRB using multiple tracers and field surveys to determine the occurrence of LGD. We employed a 222Rn mass balance model to determine LGD rates in various lakes within the central Yangtze River basin (CYRB). Additionally, we identified the factors controlling the spatial variability of the LGD rates using correlation analysis and a multiple linear regression model. Our findings revealed that while the 222Rn concentration in groundwater (6082.27 ± 3860.16 Bq/m3) was within the global average, the concentration in lake water (306.97 ± 239.45 Bq/m3) was relatively high, indicating a stronger LGD in the CYRB. The stable isotopes, 222Rn concentration, and the groundwater seepage and springs, collectively confirm the occurrence of LGD. The LGD rates in lakes within the CYRB area exhibited significant spatial variability, ranging from 13.76 to 83.96 mm/d, with larger LGD rates found at the interior of the basin than at the edges. Hydrological connectivity, location within basin, and lake water depth collectively control the LGD rate, with each contributing 53.95%, 22.90%, and 23.16%, respectively. This study not only enriches our understanding of LGD, serving as a reference for global research on LGD, but also provides theoretical guidance for local water resource management.
A forest floor evapotranspiration model incorporating forest structure for estimating under-canopy climate conditions in conifer plantations
Authors: Chiu Chenwei , Hashimoto Asahi , Inokoshi Shodai , Gomi Takashi , Onda Yuichi , Sun Xinchao
Published: March 2024

This study focuses on forest floor evapotranspiration (Ef), a critical part of the water cycle involving the atmosphere, vegetation, and soil. It specifically involves transpiration from understory vegetation and evaporation from soil surface. We acknowledge that forest structure, such as stand density and tree height, influences Ef by altering under-canopy meteorological conditions (e.g., temperature, solar radiation, and wind speed). Despite its importance, few models incorporate changes in forest structure. We address this gap by developing a model based on the Penman equation, incorporating under-canopy meteorological conditions affected by forest structure. We introduce a relative yield index (Ry), calculated as the current timber volume to the maximum timber volume ratio for specific tree heights and stand densities, with a theoretical maximum value of less than one. We tested our model in two Japanese cypress plantations with different structures (FM Karasawa and Kaisawa). Three and five micro-lysimeters were used to measure EF in a 12×13m plot in FM Karasawa and a 10×10m plot in Kaisawa, respectively. Measurements showed Ef variations from 0.0 to 2.1 mm/day in FM Karasawa and 0.1 to 2.5 mm/day in Kaisawa. The model estimated Ef in the range of 0.1 to 2.0 mm/day in FM Karasawa and 0.0 to 2.9 mm/day in Kaisawa. These results confirm the model's ability to estimate daily Ef, considering the impact of varying forest structures on micrometeorological conditions. Our findings highlight the model's potential for predicting Ef responses to different forest management strategies, offering valuable insights for sustainable ecosystem management.
Nyiragongo eruption 2021 and its environmental impact: volcanic ash fallout and high levels of trace metals in drinking water
Authors: Calabrese Sergio , Habakaramo Macumu Patrick , Bellomo Sergio , Bobrowski Nicole , Boudoire Guillaume , Brugnone Filippo , Giuffrida Giavanni Bruno , Brusca Lorenzo , D'Alessandro Walter , Gouhier Mathieu , Lentini Simone , Li Vigni Lorenza , Randazzo Luciana , Tedesco Dario
Published: March 2024

Nyiragongo (D.R. Congo) is an active volcano known for its impressive persistent lava lake within its crater, and it is recognized as one of the most dangerous volcanoes in the world because more than two million people live on its slopes. Suddenly, on 22 May 2021, Nyiragongo produced three different lateral lava flows from the southern lower flanks, and significant amounts of volcanic gas and ash were emitted from the summit crater following the collapse of the crater floor. For a few weeks, the ash fallout impacted the main city of Goma and the numerous villages located in the vicinity of the volcano. 22 samples of volcanic ashes and 135 samples of drinking water (springs, rivers, rainwater, roof runoff) were collected before, during and after the eruption. From the leaching of the ashes and their direct observation through a field emission scanning electron microscope (FE-SEM), large quantities of soluble salts (e.g. sulphates, chlorides) on their surface were identified. The results showed that most of the drinking waters collected in the downwind villages (like Rusayo, Kingi, Sake) were heavily contaminated by volcanic emissions. In fact, fluoride, chloride, sulphur, and many potentially toxic elements (PTEs), including Al, As, Cd, Cr, Cu, Fe, Mn, Mo, Pb, Sb, Se, Te, Tl, and V, exceeded the suggested World Health Organization (WHO) drinking water limits during the eruptive period, exposing the population living in villages downwind of the preferential direction of the volcanic plume, to high health risks.
River Regulation Reshaped Human-water Interaction in the Lower Yellow River Floodplain
Authors: Jiao Chentai , Wu Xutong , Song Shuang , Wang Shuai , Xiang Bei , Fu Bojie
Published: March 2024

Floodplains have been crucial agricultural and populated areas throughout history and in present. Rivers typically shape the human activities within floodplains through water supply and flood risk, forming unique human-water interaction patterns. Here, we focus on the Lower Yellow River Floodplain, where continuous levees divide homogenous cultivated plain with different flood risk, creating a quasi-natural experiment, while the river's hydrology has undergone dramatic transformation since the 1990s. We utilize Landsat-based data including open-surface water bodies, cropland and NDVI to analyze the mechanism of river-agriculture interaction and whether this mechanism has changed. The results reveal that agriculture activities were less developed inside the floodplain than outside, and were even worse in regions closest to the river. This was attributed to frequent channel diversions, heightened flood threat, and actual inundation within the floodplain. However, the Lower Yellow River experienced a silt-load reduction, trenching, and channel stabilization after the late 1990s, while submerged cropland area in the floodplain also decreased. The declining flood threat has encouraged cultivation and agriculture investment in the floodplain, consequently reducing the productivity difference across the levees. This study illustrates a prototypical human-water interaction pattern in floodplains, underscoring the significance of effective river management for sustainable development in these regions, and provides a reference on understanding regional human-environment relationship in other floodplain areas.
Temporal enrichment of the seismic record of the 2018 eruption at Sierra Negra using deep neural networks
Authors: Butcher Sophie , Bell Andrew , Hernandez Stephen , La Femina Peter , Grannell James , Ruiz Mario
Published: March 2024

The 2018 eruption at Sierra Negra volcano, Galapagos Islands, was accompanied by 8.5 metres of caldera subsidence and intense seismicity, resulting from deflation of a shallow sill-like magma reservoir at ~2 km depth. High-precision hypocentre locations from manually picked phase arrivals show that earthquake sources are tightly constrained within a complex, multi-stranded trapdoor fault system (TDF) above the sill. However, the incompleteness of this high-precision catalogue leaves outstanding questions about the spatio-temporal evolution of seismicity through the eruption, and how it relates to deformation and magma efflux.Here we present the results of an automated workflow to streamline the production of a ‘temporally-enriched’ seismic catalogue for 2018 eruption at Sierra Negra. We initially utilise PhaseNet, a deep-neural-network-based automatic phase picker, to identify events missing from the initial manually picked catalogue, expanding the detections from 1,618 to 9,871 events. Our catalogue identifies more events in the immediate aftermath of the Mw5.4 earthquake that initiated the eruption, and new small magnitude events (< ML2.0) in the period more than 72 hours after the eruption onset. We then use a template matching approach to further supplement these detections. Specifically, these events fill gaps in the catalogue where tremor amplitudes make manual event detection more difficult. Hypocentre locations for newly detected events are also constrained to the TDF zone, however there is more variety in depth estimates. This has implications for how we consider the TDF with depth, and allows us to consider other potential sources of seismicity in the system.Our workflow offers an efficient method of producing ‘temporally-enriched’ catalogues at Sierra Negra, and can be readily adapted for the sparse seismic network that remains during the current inter-eruptive phase. However, our experience at Sierra Negra suggests that applying automated earthquake detection and location methods can be challenging in volcanic settings, and requires careful parameterization and quality control.
Spatial characteristics of washovers formed in the coastal zone of the semi-enclosed tideless sea basin, Gulf of Gdańsk, Baltic Sea
Authors: Moskalewicz Damian , Bahr Felix
Published: March 2024

Storm surges lead to coastal erosion but may also leave geomorphological effects that contribute to a positive sediment budget and become a permanent or temporal part of the coastal landscape. We have investigated two study sites in the coastal zone of the Gulf of Gdańsk to examine depositional storm-induced landforms. We have measured and analysed the spatial characteristics of 244 washovers formed between 1979 and 2022. Spatial parameters like length, width, area, and perimeter of individual washovers were derived from orthophoto maps and aerial images with spatial resolution of ~0.2–1m. For the years when DEM was available for two consecutive years, the deposit volume was calculated by subtracting the DEM of the preceding year from the examined DEM. Collected data fills the gap in the knowledge of spatial characteristics of the smallest washovers, commonly forming during the relatively less powerful storms occurring in the Gulf of Gdańsk in comparison to coasts directly exposed to hurricanes or typhoons. Based on our results and data available in the literature, new scaling formulas were delivered for area-to-length, area-to-volume, and length-to-volume washover relationships. The current study indicates that spatial parameters of washover follow most of the relationships described in previous studies. However, it also suggests a more diverse view of different coastal settings impact on the formation of storm-induced landforms. The collected dataset also shows ambiguous data distribution for the smallest mapped features, indicating the influence of acquisition methodology on the data homogeneity and measuring error.
Demonstration of a deep-learning-based system for rainfall induced shallow landslides forecasting in Italy
Authors: Melillo Massimo , Guzzetti Fausto , Calvello Michele , Pecoraro Gaetano , Mondini Alessandro C.
Published: March 2024

A common and largely unresolved problem of national-scale landslide early warning systems is their independent evaluation. In this work, we evaluated the performance of a recently proposed deep-learning-based system for short-term forecasting of rainfall-induced shallow landslides in Italy. For our evaluation, we used hourly rainfall measurements from the same rain gauge network used to construct the forecasting system, and different and independent information on the timing and location of 163 rainfall-induced landslides that occurred in Italy in a period non considered in the construction of the forecasting system, obtained from the FraneItalia catalogue (https://zenodo.org/records/7923683). The independent evaluation confirmed the good predictive performance of the forecasting system and revealed no geographical or temporal bias in the forecasts. The analysis also revealed that the forecasting system was more effective at predicting multiple landslides in the same general area than single landslides. This was a good result, as multiple landslides are potentially more dangerous than single failures. Analysis of the few misclassified landslide cases showed that approximately one-third of the landslides were rockfalls, and for approximately another third there was uncertainty about when or where the landslides occurred. We conclude that, despite the inevitable misclassifications inherent in any probabilistically based national-scale landslide forecasting system, the deep-learning-based system analysed is well suited for short-term operational forecasting of rainfall-induced shallow landslides in Italy.
The soil microbiome drives priming effects in forests at a continental scale
Authors: Zhou Xuhui , Huang Changjiang , He Yanghui
Published: March 2024

The priming effect (PE), the changes in the mineralization of native soil organic carbon (SOC) in response to fresh C inputs, is a crucial biogeochemical process that affects soil C dynamics. However, how soil microorganisms regulate priming effects (positive or negative PE) at a continental scale is still unclear, potentially hampering us to better understand forest C-climate change feedback. To address this knowledge gap, we explored the controlling factors of the variation in soil PE from tropical to cold temperate forests using high-throughput sequencing and 13C-glucose tracers. Our results showed that sites with the positive PE (64.3%) were more than those with the negative ones in China’s forest. The soil microbiome (i.e., abundance of bacterial and fungal taxa) explained the largest portion of variation in priming effects (31%) compared to climate, plant traits, mineral protection, and substrate quantity properties. Specifically, abundance of bacterial taxa had a negative correlation with PE, while fungal taxa showed a positive one. Basidiomycota is the most important microbial phylum in regulating positive and negative PE, accounting for 26% of fungal taxa for positive PE and 10% for negative PE. Our results provide robust evidence that keystone taxa play a pivotal role in regulating apparent priming effects, with important implications for accurately predicting C cycling under global change.
Introduction to Earth Observation Images and Preprocessing Operational Issues of KARI's Geostationary Satellites
Authors: Park Eun-Bin , Lee Sang-Cherl
Published: March 2024

The geostationary satellites operated by the Korea Aerospace Research Institute (KARI), known as the Cheonlian satellite series, include three satellites dedicated to Earth observation missions. Cheonlian 1 (Communication Ocean and Meteorological Satellite; COMS), with a decade-long operation, utilized two onboard instruments (MI, GOCI) for Earth observation missions, accumulating approximately 600,000 images over 10 years. The Earth observation images from Cheonlian 1 can be obtained free of charge through Korean data utilization organizations (National Meteorological Satellite Center, Korea Ocean Satellite Center). The KARI ground station holds complete data related to satellite control and operation, including the Earth observation images from Cheonlian 1. After completing its Earth observation mission, Cheonlian 1 is currently operating only its communication payload. The plan is to continue operations until the launch of Cheonlian 3 in 2027, which will take over communication payload duties. Cheonlian 2A (Geo-KOMPSAT-2A; GK-2A), launched in December 2018, succeeded Cheonlian 1 in meteorological payload Earth observation tasks. Equipped with the Advanced Meteorological Imager (AMI), developed by HARRIS, Cheonlian 2A observes the globe with 16 optical bands, focusing on the Korean Peninsula. Real-time distribution of global observation images in UHRIT, HRIT, and LRIT formats is available. Cheonlian 2B (Geo-KOMPSAT-2B; GK-2B), operated since February 2020, simultaneously operates GOCI-Ⅱ and GEMS instruments for Earth observation missions. These two instruments observe only during daytime unlike meteorological payload. GOCI-Ⅱ performs Earth observation missions with a more diverse set of optical bands compared to GOCI on Cheonlian 1. Utilizing hyperspectral sensors, GEMS observes the Earth in five different areas, enabling more accurate observation of atmospheric characteristics such as aerosols. This paper provides a detailed overview of the observation areas, data types, and validation materials of Earth observation images from KARI's geostationary satellites. Additionally, it will be introduced operational issues related to Earth observation image preprocessing system of currently operational Cheonlian 2A/2B satellites. Operational issues of image preprocessing systems include various events such as failure of image reception due to environmental factors such as Sun and radio interference. Image processing failures, such as software errors, are also part of these problems. We also discuss payload anomalies that occurred during the post-launch stabilization phase. KARI is committed to continuous research and development for the stable operation of geostationary satellites, thereby ensuring the best performance for Earth observation missions.
Ion acceleration due to highly sheared tangential discontinuities at quasi-perpendicular shocks
Authors: Steinvall Konrad , Gingell Imogen
Published: March 2024

Collisionless shocks are efficient particle accelerators. While ion acceleration by shocks has been intensively studied using spacecraft data and numerical models, the main focus has been on the case of a steady upstream. In the steady upstream case, it has been shown that quasi-parallel shocks are much more efficient ion accelerators than quasi-perpendicular shocks. However, the solar wind is in general highly dynamic, containing current sheets which correspond to a magnetic shear. In this study we use a local 2.5D hybrid particle-in-cell (particle ions, fluid electrons) model to study how the ion acceleration of quasi-perpendicular shocks is affected when the upstream contains highly sheared tangential discontinuities. We show that, even in the absence of foreshock transients, the current sheets can cause a significant increase in the flux of high-energy ions. The acceleration can be explained by the following simple model. When the upstream TD is close to the shock, the shock-reflected ions can cross it during the upstream part of their gyro–motion. After crossing the TD, the large magnetic shear, corresponding to a sign change of the magnetic field direction, results in a meandering ion trajectory. This motion takes the ion further upstream, where it is further energized by the upstream convection electric field. The net effect of this process is a local ion acceleration efficiency of a few %, as quantified as the fraction of energy (in the downstream and in the downstream frame) that is carried by ions with energies larger than 10 times the upstream bulk kinetic energy. This is comparable to the efficiency of quasi-parallel shocks in the case of a steady upstream. Such discontinuities can therefore be an important source of energetic ions at quasi-perpendicular shocks, even if no foreshock transient is formed.
Quantifying the influence of cloud controlling factors with causal inference
Authors: Bock Lisa , McDonalds Adrian , Lauer Axel , Runge Jakob
Published: March 2024

As a key component of the hydrological cycle and the Earth’s radiation budget, clouds play an important role in both weather and climate. Our incomplete understanding of clouds and their role in cloud-climate feedbacks leads to large uncertainties in climate simulations. Using causal discovery as an unsupervised machine learning method we aim to systematically analyse and quantify causal interdependencies and dynamical links between cloud properties and their controlling factors. This approach goes beyond correlation-based measures by systematically excluding common drivers and indirect links. By estimating the causal effect of each of the cloud controlling factors for different cloud regimes we expect to be able to better understand the dominant processes which determine the micro- and macro-physical properties of clouds.Specifically, causal inference is used to investigate the links between cloud properties such as cloud cover, cloud water path, cloud top height and cloud radiative effects and so-called cloud controlling factors, i.e., quantities that impact cloud formation and temporal evolution of the cloud (e.g., sea surface temperature, water vapour path and lower tropospheric stability). For this, causal networks are calculated from time series of these variables from satellite and reanalysis datasets averaged over different geographical regions and cloud regimes in order to quantify the strength of the individual links in the resulting causal graph by applying causal effect estimation.
GIRAFE v1: A global precipitation climate data record from satellite data including uncertainty estimates
Authors: Konrad Hannes , Niedorf Anja , Finkensieper Stephan , Roca Rémy , Schröder Marc , Cloché Sophie , Panegrossi Giulia , Sanò Paolo , Kidd Christopher , Jucá Oliveira Rômulo Augusto , Fennig Karsten , Sikorski Thomas , Hollmann Rainer
Published: March 2024

We present a new precipitation climate data record (CDR) GIRAFE (Global Interpolated Rainfall Estimation), which has recently been released by EUMETSATs Satellite Application Facility on Climate Monitoring (CM SAF). For now, it covers a time period of 21 years (2002 – 2022) with global coverage and 1° x 1° spatial resolution. GIRAFE is a completely satellite-based dataset obtained by merging infrared (IR) data from geostationary satellites and passive microwave radiometers (PMW) onboard polar-orbiting satellites. Additional to daily sum and monthly mean precipitation rate, a sampling uncertainty on daily scale within the range of geostationary satellites (55°S-55°N) is provided. The implementation of a continuous extension of GIRAFE via a so-called Interim CDR service started and associated data will become available.For retrieving instantaneous rain rates from PMW observations, three different retrievals for microwave imagers (HOAPS) and sounders (PNPR-CLIM and PRPS) were used. Quantile mapping is applied to the instantaneous rain rates of the 19 different PMW sensors to achieve stability in GIRAFE over time. The IR observations undergo a dedicated quality control procedure. The uncertainty estimation is based on decorrelation ranges from variograms in spatial and temporal dimensions. The merging of PMW and IR data as well as the technique for uncertainty estimation in GIRAFE is based on the Tropical Amount of Precipitation with an Estimate of ERrors (TAPEER) approach.Here, we present details on the GIRAFE algorithm and uncertainty estimation as well as results of the CM SAF quality assessment activity comprised of comparisons against other established global, regional and local precipitation products.
Evaluation of the Performance of Green Roof Substrates with Recycled Materials: A Three-Year Comparative Study
Authors: Rybova Barbora , Petreje Marek , Heckova Petra , Snehota Michal
Published: March 2024

The aim of this study was to test newly developed green roof substrates with a significant content of recycled materials under real conditions and to compare them with a commercially available substrate.A two-layer extensive green roof of 7×5 m2 was constructed in 2020 and divided into four sections, two of which had top layers based on new substrates. These two substrates contained the same amount of crushed brick from demolition waste (37.5% by volume) but differed in the amount of pyrolyzed sewage sludge biochar (9.5% by volume in one and none in the other). The commercial substrate was mostly based on expanded shale, lava, and pumice. Hydrophilic mineral wool was used as the bottom layer of the green roof system to improve the water retention layer. Vegetation was established with sedum carpets.Undisturbed substrate samples were taken in 2021, 2022 and 2023 to monitor changes in hydrophysical properties (retention curves, saturated hydraulic conductivity, grain size). At the same time, vegetation development over time was monitored visually, and substrate temperature and humidity were continuously measured by autonomous sensors.Plants in the biochar and demolition debris plots rooted faster into the substrate and achieved higher cover. While plants in plots with commercial substrate or without biochar turned red in response to stress during periods of lower rainfall or more extreme temperatures, plants in the biochar-containing plot remained lush green longer. In the following year, a greater number of emergent plants (primarily grasses) that spread from the surrounding area were observed on the biochar-amended substrate. This was thought to be due to the increased availability of nutrients from biochar.Surface temperature amplitudes were higher than substrate and mineral wool temperatures, locally influenced by the plant biomass surrounding the sensors. Temperatures of the substrate and hydrophilic mineral wool were more stable. Differences in substrate temperatures were observed particularly between substrates containing recycled materials and the commercially available substrate.
Constructing a New Catalogue of Greenland's Iceberg Calving Events through Seismic Data Analysis and Machine Learning
Authors: Wetter Selina , Hibert Clément , Mangeney Anne , Stutzmann Eléonore
Published: March 2024

The Greenland ice sheet, a critical component of the global climate system, has played a substantial role in rising sea level, marked by a fourfold increase in mass loss due to iceberg calving between 1992-2000 and 2000-2011. Through the quantification of the spatio-temporal changes in Greenland’s ice mass loss resulting from iceberg calving, we gain a deeper understanding of the impacts of climate change.The mass loss related to calving icebergs can be estimated by combining mechanical simulation of iceberg calving and inversion of seismic data. Seismic signals are generated by the time-varying force produced during iceberg calving on marine-terminating glacier termini. These events, known as glacial earthquakes, are recorded by the Greenland Ice Sheet Monitoring Network at tens of kilometres from the source.However, differentiating these signals from tectonic events, anthropogenic noise, and other natural noise is challenging due to their complex frequency content (1-100s), multi-phase waveforms and low amplitude. To overcome this difficulty, we use a detection algorithm based on the Short-Time Average over Long-Time Average (STA/LTA) method and combine it with machine learning (Random Forests). By training the machine learning algorithm on seismic event catalogues containing more than 400 earthquakes and glacial earthquakes each, our approach is apt for identifying glacial earthquakes. Applying this methodology to continuous data offers the possibility to uncover smaller and previously undetected events. As a result, we present a comprehensive catalogue spanning several years and discuss its relevance and reliability. The generated catalogue allows us to develop new methods to better understand the spatio-temporal evolution of the ice-calving activity in the region. Among these, we will initially focus on locating and inverting the force of the largest events, providing a basis for testing new machine learning approaches for the characterisation of the source. This includes extracting properties like the iceberg volume and shape from both large and smaller events, ultimately advancing our understanding of Greenland's ice mass loss dynamics.
Seismic evidence of upper mantle melt caused by a subducted slab in the Indian-Eurasian continental subduction zone
Authors: Li Guohui
Published: March 2024

A low-velocity layer atop the mantle transition zone has been extensively observed worldwide, which may play an important role in mantle dynamics and Earth habitability. In subduction zones, this layer is widely explained as partial melting triggered by slab subduction on a regional or global scale. However, direct observational evidence is still absent, and the response of the layer to slab subduction is not well known. Here, we image the seismic velocity around the mantle transition zone by matching synthetic and observed triplicated seismic P and sP waveforms in the Indian–Eurasian continental subduction zone. Our observations reveal a laterally varied low-velocity layer atop the mantle transition zone beneath the Hindu Kush, where a subducted slab extends to the mantle transition zone. It is characterized by thickness of 56-94 km and P-wave velocity drop of -2.8~-4.7%. The geometric morphology of the low-velocity layer indicates that it is a partially molten layer induced by the subducted slab on a regional scale. Interestingly, our observations also support that the layer has a low viscosity. The decreased viscosity possibly facilitates slab motion in the deep domain; however, the buoyant continental crust in the shallow domain likely resists downwards movement of the slab. This differential movement is more likely to cause slab stretching, tearing and break-off in the middle region, which may contribute to explaining rare recurring large intermediate-depth earthquakes in an intracontinental setting.
Multiple extractions of the Cretaceous silicic magma plumbing system beneath the Baiyunzhang-Lianhuashan Basins, eastern Guangdong, SE China
Authors: Xia Yan , He Jianqiang , Xu Xisheng
Published: March 2024

The extensive magmatism along the southeastern coast of China during Late Cretaceous time formed a volcanic-intrusive complexes belt, on which many volcanic basins and calderas are located. A growing amount of research has been carried out to reveal the formation processes of the Cretaceous volcanic-intrusive complexes in SE China, especially the volcanic-plutonic complexes in Zhejiang and Fujian Provinces. However, volcanic-plutonic complexes in Guangdong Province have not received enough attention in the past relative to volcanic-plutonic complexes in Zhejiang and Fujian Provinces. Furthermore, it is difficult to identify the genetic connections and formation processes of different type of volcanic rock with its co-genetic intrusive rocks in volcanic basins or calderas with complex igneous rock types, but it also provides new insights into the volcanic plumbing system processes and magma reservoir differentiation. Therefore, we conducted detailed research on the volcanic-plutonic complexes in the Lianhuashan Basin and Baiyunzhang Basin in the Lianhuashan Fault Zone. The Lianhuashan volcanic-plutonic complex is comprised of ignimbrite, granite porphyry and rhyolite porphyry, while the Baiyunzhang volcanic-plutonic complex is comprised of ignimbrite, trachyte, rhyolite and quartz monzonite porphyry. The LA-ICP‒MS zircon U‒Pb dating results indicate that the crystallization of volcanic and intrusive rocks was contemporaneous within the error (143~138 Ma), and they had similar ranges of zircon Hf-O isotopes (εHf(t)= -2.8 to 8.9; δ18O=5.53 to 7.87 ‰) and whole-rock Nd isotopes (εNd(t)=-3.4 to -5.7). In addition, samples with high SiO2 contents (SiO2 ≥ 70 wt.%) exhibit high Rb/Sr ratios and depletions in Ba, Sr, P, Ti and Eu, while the samples with low SiO2 contents exhibit low Rb/Sr ratios and weak depletions in Ba, Sr, P, and Ti with insignificant negative Eu anomalies. Therefore, we suggest that the parent magmas of the Baiyunzhang-Lianhuashan Basins originated from the same deep-level magma reservoir, which underwent pulsatile magma extraction and formed two shallow-level magma reservoirs. The two shallow magma reservoirs each underwent different degrees of crystallization differentiation and crystal-melt separation, eventually forming ignimbrite, trachyte, rhyolite, granite porphyry and rhyolite porphyry through pulsed extraction. The remaining crystal mush consolidated in situ to form quartz monzonite porphyry intrusive rocks.
Towards an online ramped oxidation approach for thermal dissection and serial radiocarbon measurement of complex organic matter
Authors: Bolandini Marco A. , De Maria Daniele , Haghipour Negar , Wacker Lukas , Hemingway Jordon D. , Eglinton Timothy I. , Bröder Lisa
Published: March 2024

Radiocarbon (14C) measurements provide a powerful tool to deconvolute sources and dynamics of organic matter in the environment. However, interpretation of conventional bulk-level 14C data is challenging due to the myriad components comprising organic matter in soils and sediments. Thermally ramped oxidation provides one approach for overcoming this limitation, and involves subjecting a sample to gradually increasing temperatures, serially oxidizing the OC to CO2. Collected over prescribed temperature ranges ('thermal fractions'), this CO2 is then analyzed for 14C content using accelerator mass spectrometry (AMS). While effective, current ramped oxidation methods are mostly 'offline', involving manual collection and subsequent AMS analysis of evolved CO2, hindering sample throughput and reproducibility.Here, we introduce a compact, online ramped oxidation (ORO) setup in which CO2 from discrete thermal fractions is directly collected and measured for 14C by AMS equipped with a gas ion source. The setup comprises two modules: (i) an ORO unit with two sequential furnaces - the first, ramped from room temperature to 900 °C, holds the sample; the second, maintained at 900 °C, includes a catalyst ensuring complete oxidation to CO2; and (ii) a dual-trap interface (DTI) collection unit with two parallel molecular sieve traps alternately collecting and releasing CO2 from a given fraction for direct injection into the AMS.Preliminary results indicate reproducible data, evident in both thermograms and F14C results. Analysis of natural reference samples reveals that measured 14C values and their associated uncertainties align with those reported in the literature using conventional “off-line” ramped oxidation methods, affirming the utility of the new ORO-DTI-AMS setup.Our goal is to apply this new method for comprehensive investigation of a range of natural samples, with a particular focus on the improved understanding of the fate of OC held in permafrost soils in the context of on-going climate and carbon cycle change in high latitude ecosystems.
Experimental constraints on tidal dissipation in silicate cores of icy satellites
Authors: Seltzer Cassandra , O. Ghaffari Hoagy , Peč Matěj
Published: March 2024

The habitability of icy moons in the outer Solar System is linked to their ability to maintain warm subsurface oceans through time. While most heat generation in response to tidal forcing is thought to occur in icy crusts and water oceans, the actual response of silicic material to deformation under relevant planetary conditions has not previously been studied comprehensively in a laboratory setting. Similar meteoritic material is often studied at room pressure instead of at the 10s to 100s of MPas of pressure present at depth in moons, and subjected to dynamic forces to simulate impacts rather than observed under quasistatic loading and deformation. In the absence of laboratory constraints on peak strength and deformation behavior, large errors remain for estimates of heat contribution from the mantles, as well as in models of seismic and elastic properties of icy moon interiors.We experimentally deformed samples of the Kilabo meteorite, an LL6 chondrite, under axial strain rates of 10-5 s-1 and confining pressures up to 100 MPa. We recorded the strength of the material, calculated energy dissipation through acoustic emission events, and measured how ultrasonic wavespeeds evolved as a function of confining pressure. Dissipative microcracking events occurred at all pressures, even at low stresses during isotropic pressurization and nominally “elastic” deformation. These events were most common at low confining pressures. The mechanical behavior of the meteoritic material also evolved as a function of confining pressure: peak strength occurred at 50 MPa laboratory confining pressure, and material continuously stiffened as pressure increased. These pressure-dependent properties indicate that larger icy planetary bodies may have stiffer, less deformable silicate layers than those found in small icy satellites. Rocky interior deformation could therefore contribute to the bulk heat budget required to maintain subsurface oceans in Ariel and Miranda, along with many other smaller icy moons in the outer Solar System.  