bluuebunny/crossref_metadata_2025 huggingface dataset:
Relation between Latitude-dependent Sunspot Data and Near-Earth Solar Wind Speed
Authors: Jiao qirong , liu wenlong , zhang dianjun , cao jinbin
Published: March 2024

Solar wind is important for the space environment between the Sun and the Earth and varies with the sunspot cycle, which is influenced by solar internal dynamics. We study the impact of latitude-dependent sunspot data on solar wind speed using the Granger causality test method and a machine-learning prediction approach. The results show that the low-latitude sunspot number has a larger effect on the solar wind speed. The time delay between the annual average solar wind speed and sunspot number decreases as the latitude range decreases. A machine-learning model is developed for the prediction of solar wind speed considering latitude and time effects. It is found that the model performs differently with latitude-dependent sunspot data. It is revealed that the timescale of the solar wind speed is more strongly influenced by low-latitude sunspots and that sunspot data have a greater impact on the 30 day average solar wind speed than on a daily basis. With the addition of sunspot data below 7.°2 latitude, the prediction of the daily and 30 day averages is improved by 0.23% and 12%, respectively. The best correlation coefficient is 0.787 for the daily solar wind prediction model. 
A novel full MHD forecasting model chain from Sun to Earth: COCONUT+ Icarus
Authors: Baratashvili Tinatin , Brchnelova Michaela , Guo Jin Han , Lani Andrea , Poedts Stefaan
Published: March 2024

Space weather events can affect Earth. In order to mitigate damage, space weather modelling tools have been implemented. In this study, the full MHD chain is presented, starting from the Sun, with a 3D MHD data-driven coronal model COCONUT up to 0.1 AU, where the code is coupled to Icarus, an ideal 3D MHD heliospheric modelling tool.COCONUT (Perri, Leitner et al. 2022, COolfluid COrona Unstructured) is a data-driven coronal model that was recently developed at the Centre for Mathematical Plasma Astrophysics, KU Leuven. It is a global 3-D MHD model based on the COOLFluiD code (Yalim et al. 2011, Lani et al. 2014). The advantage of the COCONUT model lies in its efficient, optimised implementation. It uses a time-implicit backward Euler scheme and unstructured computational grid, which avoids singularities near the poles and enables using high CFL numbers to rapidly converge to steady state for realistic simulations on modern HPC systems. In order to obtain realistic solar wind conditions at 0.1AU, the source terms have been implemented in the MHD equations, namely, the approximated coronal heating function, radiative losses and the thermal conduction. The output of the COCONUT coronal model is used as input boundary conditions for plasma variables in the heliospheric model Icarus.Icarus (Verbeke et al. 2022, Baratashvili et al. 2022) is a new heliospheric wind and CME evolution model that is implemented within the framework of MPI-AMRVAC (Xia et al., 2018) and introduces new capabilities for better and faster space weather forecasts. Advanced numerical techniques, such as solution adaptive mesh refinement (AMR) and radial grid stretching, are implemented. These techniques result in optimised computer memory usage and a significant execution speed-up, which is crucial for forecasting purposes.The modelled 3D data in the solar corona and heliosphere are presented for assessing the model capabilities. The density profiles near the Sun are compared to tomography data. The time-series profiles of different variables at Earth are compared to observational data. As a result, the COCONUT+Icarus model chain represents the full MHD model covering the domain from Sun to Earth, which allows more in depth studies and understanding of different physics phenomena, e.g. shock formation, erosion, and deformation, compared to empirical or semi-empirical models. 
Modelling Cystoseira s.l.-turf competition via a space-implicit model with border dynamics
Authors: Materassi Massimo
Published: March 2024

This paper presents a model of competition between the arborescent canopy-forming algae Cystoseira s.l., and the smaller size algae forming turf on rocky bottoms. The two algal assemblages are both grazed by sea urchins. The algae and invertebrates involved in the model play an important role in the health of coastal ecosystems and particularly in the conservation of biodiversity-rich habitats of temperate nearshore rocky reefs: the model presented is intended to help describing real ecological processes of canopy degradation and recovery. The model is a 3-species space implicit food web. Its distinctive feature is the inclusion of community border effects in interactions, as only the individuals laying along the canopy border of Cystoseira s.l. forests take part in recruitment and competition with algal turfs, and undergo grazing by sea urchins. Also endogenous recruitment of turf involves only border individuals. These border effects are taken into account in the same way of herd behavior in the mathematical ecology of animal species. Some important features of the model phase space are investigated, focussing on the capacity of the system to mimic the transitions among ecologically different states of the rocky bottom (canopy, turf, and barren).
Probabilistic hazard modelling of the natural gas emission of Mefite d’Ansanto, Southern Italy
Authors: Dioguardi Fabio , Chiodini Giovanni , Costa Antonio
Published: March 2024

The emission of gas species dangerous for human health and life is a widespread source of hazard in various natural contexts. These mainly include volcanic areas but also non-volcanic geological contexts. A notable example of the latter occurrence is the Mefite d’Ansanto area in the Southern Apennines in Italy. Here, significant emissions of carbon dioxide (CO2) occur at rates that make this the largest non-volcanic CO2 gas emission in Italy and probably of the Earth. Given the morphology of the area, in certain meteorological conditions a cold gas stream forms in the valleys surrounding the emission zone, which proved to be potentially lethal for humans and animals in the past. In this study we present a gas hazard modelling study that considers the main specie, that is CO2, and the potential effect of the most dangerous, which is hydrogen sulphide (H2S). For these purposes we used VIGIL, a tool that manages the workflow of gas dispersion simulations specifically optimised for probabilistic hazard applications. We produced maps of CO2 and H2S concentration and persistence at various exceedance probabilities considering the gas emission rates and their possible range of variation defined in previous studies.
The Circum-global Transport of Massive African Dust and its Impacts on the Regional Circulation in Remote Atmosphere
Authors: Hongru Bi , Siyu Chen , Daizhou Zhang
Published: March 2024

Atmospheric dust from the North Africa, the largest and most persistently active dust source over the world, spreads widely in the Northern Hemisphere and plays essential roles in the Earth environment evolution. During June 7th-24th 2020, an extremely strong dust occurred with its westward spreading modulated by the North Atlantic Oscillation (NAO), and its eastward spreading regulated by European blocking, ultimately resulting in the circum-global transport of African dust. The Mediterranean low pressure linked to the European blocking dipole was the key to facilitating the eastward transport of dust. This record-breaking African dust episode caused a notable diurnal precipitation decrease of 0.98 mm day-1 over northeastern India and decrease of 1.55 mm day-1 over central North America, which was ascribed to the effect of dust-induced radiative heating on large-scale circulation. It triggered Rossby wave train and caused an anomalous high pressure over northeastern India, which weakened the India summer monsoon and consequently inhibited the occurrence of precipitation. Dust-induced radiative heating also supported the stability in the anomalous warm high over North America, further repressing import of moisture from Atlantic. Ambient moisture and atmospheric instability also presented consistent variation over North America and India characterized as strengthen descending motion and sharply reduced moist convection. This study reports, for the first time, the strong modulation of regional circulation by circum-globally transported African dust especially in Asia and North America. The new aspects on the unexpected consequences to moisture convection indicate broader roles that the dust may play in the global climate change.
The mechanism of multi-year La Niña events and their impact on spring precipitation over southern China
Authors: Feng Licheng , Li Guangliang , Zhang Ronghua
Published: March 2024

By diagnosing and analyzing the frequent occurrence of multi-year La Niña events in recent years, this study reveals the process and mechanism of the Southeast Pacific subsurface cold water triggering multi-year La Niña events. Revealing for the first time the propagation channels and physical processes of multi-year La Niña events triggered by subsurface cold water. In late spring and early summer, the anomalous eastward wind strengthens in the central equatorial Pacific, while abnormal wind stress divergence occurs in the eastern Pacific, which strengthens and spreads westward over time. The weak negative sea surface temperature anomaly in the eastern equatorial Pacific is accompanied by upwelling, providing a source of cold water for the surface. As the season progresses, the weakened equatorial undercurrent and the enhanced southern equatorial current cause cold water to spread westward and accumulate in the central Pacific, thereby extending upwards to expose the sea surface. The exposed cold water causes a cooling of the sea surface and triggers local sea atmosphere interactions, leading to abnormal development of sea atmosphere and ultimately forming a multi-year La Niña events. Composite analyses were performed in this study to reveal the differences in spring precipitation over southern China during multiyear La Niña events from 1901-2015. It was found that there is significantly below normal precipitation in the first boreal spring, but above normal in the second year. The differences in spring precipitation over southern China are correlative to the changes in anomalous atmospheric circulations over the northwest Pacific, which can in turn be attributed to different anomalous sea surface temperatures (SSTs) over the tropical Pacific. During multiyear La Niña events, anomalous SSTs were stronger in the first spring than those in the second spring. As a result, the intensity of abnormal cyclones (WNPC) in the western North Pacific Ocean (WNP) in the first year is stronger, which is more likely to reduce moisture transport, leading to prolonged precipitation deficits over southern China. In contrast, the tropical SST signal is too weak to induce appreciable changes in the WNPC and precipitation over South China in the second year. The difference in SST signals in two consecutive springs leads to different spatial patterns of precipitation in southern China by causing different WNPC.
RE:Growth—A Google Earth Engine toolkit analyzing secondary forest carbon dynamics in the Brazilian Amazon
Authors: Heinrich Viola , Sitch Stephen , Rosan Thais , Silva Junior Celso , Aragão Luiz
Published: March 2024

Secondary forests, forest naturally regrowing on areas of previously deforested, now abandoned lands are crucial to help maintain and increase the carbon sink on land, helping to tackle the climate and ecological emergencies. There is a growing research field on improving our understanding of the carbon dynamics of secondary forests, often using novel remote sensing techniques to map the temporal and spatial patterns of change. However, the full datasets from the research are often not fully accessible to all users, either because the whole dataset is not published, or because it is presented in a specialist format. Given both the scientific and policy interest in forest-carbon dynamics, it is critical to ensure datasets are accessible to a wide range of audiences. Here we present “RE:Growth” – a user-friendly toolkit designed in Google Earth Engine, enabling users to view and download the aboveground carbon dynamics spatially and temporally in secondary forests in one of the largest tropical forest regions; the Brazilian Amazon. Designed to be easily updated as more temporal and spatial data are made available, ‘RE:Growth’ provides spatial and aggregated information on carbon flux dynamics in secondary forests through time based on Earth Observation. Uniquely, the user can draw their own region or select a jurisdictional boundary in the Brazilian Amazon to focus the analysis to their region of interest. Such information can be used within the measurement, reporting and verification framework, which is critical for results-based payments at all scales. For example, the toolkit can be used to provide spatial and quantitative data to inform the spatial prioritization of secondary forest conservation and expansion in line with Brazil’s Nationally Determined Contributions (NDC) to the Paris Agreement.
Is spring melting in the Arctic detectable by under-ice radiation?
Authors: Anhaus Philipp , Katlein Christian , Nicolaus Marcel , Planat Noémie , Schiller Martin
Published: March 2024

A trend towards earlier sea-ice melt is detected in many ice-covered regions in the Arctic. The timing of the melt onset has a strong impact on the sea-ice energy budget. Melt onset changes the radiative properties of the ice due to increasing snow wetness and meltwater. So far, satellite passive microwave data are used to detect the melt onset. We analyzed transmitted radiation spectra as collected underneath drifting sea-ice using a remotely operated vehicle during the ARTofMELT expedition in the Fram Strait in spring 2023. We colocated those spectra with measurements of snow depth, sea ice and surface topography, chlorophyll-a concentration in the water column, and with aerial images. This combined dataset enables us to track down possible subsurface pathways and accumulation pools of meltwater. Areas of low snow load and depressed surface topography are characterized by higher transmitted radiation compared to areas with a thick snow cover. Those areas overlapped with areas that showed the first signs of surface melt. Chlorophyll-a concentrations varied only slightly in magnitude and did not match with the heterogeneous pattern of snow depth and ice topography. Here we discuss how to disentangle the influences of chlorophyll a and the subsurface meltwater on the spectral shape of transmitted radiation. We propose that upon successful disentanglement, the spectra can be used as an indicator for subsurface melting. Our study suggests that sea-ice melting starts subsurface and that measurements of transmitted solar radiation spectra could be used to identify the melt onset prior to surface melting. This can provide an interesting complementary information on melt occurrence and on the location of the water in the snowpack in addition to satellite passive microwave data.
Broadband Ground Motions Simulations for M≥6.0 Earthquakes in the 2016/2017 Central Italy Seismic Sequence through a 1D Frequency-Wavenumber Approach: a Velocity Models Sensitivity Analysis 
Authors: Artale Harris Pietro , Pitarka Arben , Akinci Aybige
Published: March 2024

The Central Italy area close to the town of Amatrice was hit by a seismic sequence that started with a Mw 6.2 mainshock and lasted more than 1 year, with the highest event being the Mw 6.5 earthquake in Norcia. Reliable prediction of ground motion is difficult due to the limited data available particularly in the near-source; for this reason, we need realistic simulations of near-source broadband ground motion for seismic hazard assessment. Such simulations should be accurate and computationally efficient. In this work, we performed physics-based simulations to investigate ground motion variability for the Amatrice and Norcia earthquakes. Using the Frequency-Wavenumber (FK) technique we generated broadband ground motion time histories up to 10 Hz for both earthquakes. We exploited accurate source rupture models and various sets of Green’s functions generated with 1D velocity models obtained by slightly modifying the 1D velocity model of the Central Apennine Area proposed by Hermann et al. (2011). First, we employed the Graves and Pitarka (2016) technique to generate kinematic rupture models. Then, FK Green's functions are computed using the propagator matrix method proposed by Zhu and Rivera (2002). Using the RotD50 SA goodness of fit (GoF) between the recorded and simulated ground motion, we conducted 1D velocity model sensitivity analysis. Overall, the simulated time histories match well the recorded ground motion. We found that the 1D velocity model of the Central Apennine Area, modified for the inclusion of thin near-surface sedimentary layers, performed better than the other 1D velocity models considered in the GOF analysis. Our ground motion simulations suggest that the FK-based simulation approach can effectively reproduce the recorded ground motion in the frequency range of 0-10 Hz. Consequently, this approach holds promise for the seismic hazard assessment in Central Italy, enabling significant computer time savings compared to more complex methodologies that involve 3D wave propagation modeling.
Peatland carbon dynamics in a changing climate: A 13-year flux time series of a fen in Northern Finland 
Authors: Kübert Angelika , Aurela Mika , Hatakka Juha , Laurila Tuomas , Linkosalmi Maiju , Rainne Juuso , Tuovinen Juha-Pekka , Vekuri Henriikka , Lohila Annalea
Published: March 2024

Northern peatlands act as a global carbon sink. At the same time, they are a major source of methane. Rising temperatures due to global warming may severely change carbon dynamics. However, long-term studies to evaluate the impact of global warming on northern peatland ecosystems are rare. Here, we monitored carbon dioxide (CO2) and methane (CH4) dynamics at a subarctic/boreal fen in northern Finland throughout 13 years (2007-2019) using the eddy covariance technique accompanied by measurements of abiotic and biotic drivers. Mean yearly CH4 and CO2 exchange were +21.7 g CH4 and –0.14 kg CO2, respectively. The peatland was an average sink of carbon, with a mean annual uptake of –21.4 g C. It remained also a sink during the exceptionally warm summer of 2018 (–52.3 g C y-1). Soil temperatures strongly drove CH4 emissions whereby summer soil temperatures governed the annual budget (p < 0.001) and summer emissions determined the annual budget (45-57%, p < 0.001). Observed warming in late summer (+2.1 °C, 2007-2019) did not increase CH4 emissions as soil temperatures remained unchanged. Air and soil temperatures during the growing season and the number of snow-free days controlled annual net CO2 exchange (p=0.003). We found an increasing trend in respiration and primary production in the late growing season, keeping net CO2 exchange equally. Warmer temperatures in the late growing season increased respiration, however, primary production responded only positively to warmer temperatures in spring. Instead, warmer late summers and longer extended autumn growing seasons likely delayed autumn senescence and increased greenness, keeping primary production high. Our results suggest that with ongoing global warming and rising summer soil temperatures, methane emissions from boreal peatlands will further increase, feedbacking on the climate through its high global warming potential. The carbon sink potential will be determined by the number of snow-free days and growing season temperatures. Vegetation changes in the late growing season may offset higher respiration due to warming.  
Textural studies of Magnetite from the rocks of Beldih, Purulia, West Bengal 
Authors: Ghosh Reeya , Kumar Ozha Manoj
Published: March 2024

Kiruna-type Fe-oxide-apatite (IOA) mineralization is a potential source of phosphorous, iron rare earth elements (REEs), and other elements (Ag, Cr, Co, and U) of economic importance. In such deposits, textures associated with ore minerals provide important insights that can aid in characterizing the primary/secondary phases vis-à-vis the process of mineralization. Accordingly, apatite-magnetite veins (associated with calcite-bearing ultramafic rocks) from the Beldih area (South Purulia Shear Zone) of Eastern India were studied to appraise the formation of Fe-oxides and sulfide minerals hosted within these rocks. The present work integrates preliminary Petrological studies (both under microscope and Backscattered electron: BSE imaging) to comprehend the texture/s of Fe-Ti oxides and associated sulfides. The major/dominant phases in the samples comprise magnetite and ilmenite (among the Fe-Ti oxides) and pyrrhotite, pyrite, chalcopyrite, sphalerite, cobaltite, and gersdorffite (as sulfide phases). These rocks in the study area preserve varied textural assemblages/associations of magnetite: (a) Magnetite (Mag1) in the samples is coarse-grained with euhedral/polygonal grain boundaries, in which larger grains preserve two different sets of fine lamellae of ilmenite (in addition to individual grains) exhibiting both Trellis intergrowth and Widmanstatten texture; and (b) medium-sized, discrete grains of magnetite (Mag2) and ilmenite at the boundary of large pyrrhotite grains (associated with pyrite and chalcopyrite). Both these textural types include euhedral grains of apatite embedded on clusters of calcite, associated with minor REEs (allanite and monazite) and silicate phases (amphibole, biotite, muscovite, and titanite). Pyrite grains (exhibiting sharp boundary) in the rock are found both as inclusions and at the grain boundary of large (anhedral) pyrrhotite grains, indicating possible alteration of pyrite to form pyrrhotite. Inclusions of gersdorffite are also seen within a few pyrrhotite grains. Thus, from the afore-discussed textural assemblage of magnetite (Mag1), it stands to reason that high-fO2 environment prevailed during its formation and the possible difference of pressure in the solid solution between magnetite and ilmenite. The formation of Fe-oxides, calcite, apatite, and silicates is consistent with the primary crystallization of these minerals possibly from a silicate melt (by liquid immiscibility process) or from a high-T magmatic-hydrothermal fluid. Subsequently, the formation of secondary discrete magnetite (Mag2) and associated ilmenite grains (in addition to various sulfide phases), indicates possible ingress of a hydrothermal fluid into the system.
EST-LEAF – new tool to measure and determine leaf inclination angle distribution (LIAD) information with your phone
Authors: Borysenko Oleksandr , Pisek Jan
Published: March 2024

Leaf angle distribution is a crucial structural trait in plants, influencing aspects such as radiation interception, biomass production, rainfall interception, and evapotranspiration. However, there is a limited number of reported measurements for leaf inclination angle distributions across various plant species in existing literature and databases such as TRY. Frequently, modellers rely on assumptions due to the scarcity of data on leaf angle distribution, making it a major source of uncertainty in ecological models.To try to alleviate this issue, we present EST-LEAF, a mobile application designed for the intuitive measurement of angles and instantly obtaining leaf angle distribution using a mobile phone. Leaf inclination angles are measured using the phone placement. The application promptly calculates essential distribution parameters, including mean, standard deviation, Campbell, beta distribution parameters, G-function, and deWit type. The measurements and results can be stored and exported for future analysis.We validated EST-LEAF's performance against alternative, more time-consuming methods commonly used in the field (a protractor, digital levelled photography). EST-LEAF can be an affordable and valuable tool suitable for verifying various ecological hypotheses and supporting canopy modelling approaches. It is important to note that the tool can contribute to ecophysiological and educational projects, given its affordability and user-friendly nature, making it accessible to institutions, researchers, and students worldwide. The EST-LEAF app is available for free under a Creative Commons license (CC BY-NC-SA 4). It can be downloaded from the Google Play Market onto devices with Android systems.
Enhanced cross-shelf exchange by the eddies associated with plume front
Authors: Zu Tingting , Liu Zhiqiang , Cai Zhongya , Qu Lixin
Published: March 2024

Broadened width of high chlorophyll concentration band with wavy structures, patches and filaments are often observed along the western coastal next to the Pearl River Estuary over the northern South China Sea shelf during the transition period from winter to summer monsoon. Whereas, there is no such wide band in other seasons. By using a high resolution numerical model, we reveal that the complex structure and wider band of high coastal chlorophyll concentration results from the smaller scale eddies (about 20-50km in diameter) associated with buoyant plume and thermal fronts, which are roughly along the 30m and 50m isobaths, respectively. Two trains of eddies are formed along the fronts by the baroclinic instability triggered by frequently alternating wind over the fronts during the monsoon transition period. The influences of these two trains of eddies are extended in the cross-shelf direction by their interactions, and they temporally enhance the cross-shelf flow and material exchange. They serve as an efficient pathway to link the inner shelf towards the slope.
Assessment of the optimal initial and boundary conditions for the LES-based model PALM
Authors: Radovic Jelena , Belda Michal , Resler Jaroslav , Eben Kryštof , Bureš Martin , Geletič Jan , Krč Pavel , Řezíček Hynek , Fuka Vladimír
Published: March 2024

Proper assessment of urban atmosphere and climate by physics-based Computational Fluid Dynamic (CFD) models has been a pressing topic in the urban modeling community. Due to the ever-increasing number of city dwellers, continuous urbanization, and consequent modification of the urban atmosphere, this topic is and will remain popular in the future. The most advanced microscale models widely used for urban boundary layer studies, typically based on the Large Eddy Simulation (LES) principle, are currently the ones whose higher accuracy and ability to capture physical processes in the urban atmosphere have been well-validated. However, to fully assess their reliability, the necessity of testing the influence of the initial and boundary conditions (IBC) on the model outputs is a crucial issue that needs to be addressed.Four different three-day episodes throughout the year 2019 have been modeled using the PALM model system for experiment purposes. Two of the episodes encompass extreme weather events (e.i., a heatwave and a bad air quality period), and the other two episodes are chosen to represent non-extreme and usual weather conditions. In this experiment, an ensemble of 16 different WRF model realizations differing in parameterization setup is created and it serves as a source of IBC for the PALM model simulations. Firstly, a method for optimal WRF ensemble member selection has been developed, based on which subgroup of the ensemble members has been selected for driving the microscale model. The microscale model 8 x 8 km simulation domain is located in the realistic urban area in the city of Prague,  its horizontal resolution is 10m. Altogether, 14 simulations have been performed with identical configurations except for the driving conditions. The PALM model outputs have been evaluated against radio-soundings, and compared to the WRF model driving conditions, both quantitatively and qualitatively. This study shows that PALM model outputs are largely influenced by the imposed driving conditions and that the majority of errors originate from the mesoscale model, and propagate into the microscale simulation. The sensitivity of the microscale model on different IBCs is significant, but the PALM model is capable of attenuating the errors coming from the WRF model. Finally, the experiment stresses the importance of high-quality driving data and shows the complexity of the process of acquiring such data.
Characteristics of ice nucleating particles in the marine atmosphere from the South China Sea to the eastern Indian Ocean
Authors: Hu Wei , Duan Peimin , Niu Mutong , Jin Rui , Wu Zhijun , Fu Pingqing
Published: March 2024

Marine aerosols can act as ice nucleating particles (INPs) and thus influence cloud microphysical properties, water cycle, and global climate. The low concentrations and high variability of INPs in the marine atmosphere lead to difficulties in their measurement and characterization and lack of observational data. In particular, there is a large gap on atmospheric INPs over tropical oceans, especially the Indian Ocean, which may cause large uncertainties in the simulation of atmospheric INPs, resulting in radiation flux errors and thus affecting the climate sensitivity in models. In order to characterize atmospheric INPs over tropical oceans, airborne total suspended particles (TSP) and rainwater samples were collected during a cruise from the South China Sea to the eastern Indian Ocean during April to June 2021. Using the ice nucleation detection device (TJU-INA) combined with multiple treatments, the levels of total INPs and INP compositions including organic, nanoscale (
Combining TROPOMI with high-resolution satellites to detect, attribute, and monitor large methane emission events.
Authors: de Jong Tobias A. , Maasakkers Joannes D. , Sharma Shubham , Schuit Berend , Dogniaux Matthieu , Tol Paul , Irakulis-Loitxate Itziar , Randles Cynthia A. , Aben Ilse
Published: March 2024

Anthropogenic methane emissions play an important role in exacerbating climate change, and thus there is a need for accurate and timely monitoring and mitigation of these emissions. With daily global coverage, TROPOMI, onboard Sentinel-5P, maps methane concentrations at 5.5 x 7 km2 resolution and can detect methane super-emitters (>~8 t hr-1) globally [1,2]. Here, we show how we detect, attribute, and quantify methane emissions from super-emitters using TROPOMI in combination with information from high-resolution satellite instruments to support the UNEP IMEO Methane Alert Response System (MARS). To determine optimal targets for high-resolution hyperspectral observations (e.g. PRISMA, EnMAP), we combine longer term TROPOMI data over persistent emitters. When emissions are transient, we combine TROPOMI with data from non-targeted high-resolution band imagers (also known as multispectral sensors) such as Sentinel-2 and Sentinel-3 to trace emissions to facility-level emission sources, in particular oil and gas infrastructure [3]. We illustrate how the combination of satellites with different overpass times and different spatial resolutions gives a comprehensive picture of these emissions. To evaluate the detections, we compare methane enhancements retrieved from band imagers with values from TROPOMI. Even when overpass times do not match, we achieve this by using transient emissions that result in methane plumes with a constant total mass, once detached from the source. Finally, we show how combining information from multiple satellites enables critical evaluation of the winds taken from global reanalysis products that underlie almost all high-resolution emission quantifications based on mass-balance methods. References[1]        Maasakkers JD, Varon DJ, Elfarsdóttir A, McKeever J, Jervis D, Mahapatra G, et al. Using satellites to uncover large methane emissions from landfills. Sci Adv 2022;8:eabn9683. https://doi.org/10.1126/sciadv.abn9683.[2]       Irakulis-Loitxate I, Guanter L, Maasakkers JD, Zavala-Araiza D, Aben I. Satellites Detect Abatable Super-Emissions in One of the World’s Largest Methane Hotspot Regions. Environ Sci Technol 2022;56:2143–52. https://doi.org/10.1021/acs.est.1c04873.[3]       Pandey, Sudhanshu, et al. "Daily detection and quantification of methane leaks using Sentinel-3: a tiered satellite observation approach with Sentinel-2 and Sentinel-5p." Remote Sensing of Environment 296 (2023): 113716. https://doi.org/10.1016/j.rse.2023.1137
Deep-Time.org: One-Stop Online Research Platform for Geoscientists
Authors: Du Zhenhong
Published: March 2024

Big Data and AI have transformed Earth sciences, enabling data-driven discovery. While digital infrastructures have simplified access for most, deep-time geoscience faces challenges with scattered heterogeneous data and traditional theoretical methods. To overcome this, we propose the Deep-time Platform—a one-stop online research platform for geoscientists. Utilizing cloud computing and advanced tech, it offers open access to deep-time geoscientific data, knowledge, models, and computing power. The Deep-time Engine ensures seamless coordination. The Platform is aimed at enabling and empowering global geoscientists’ collaborative innovation and discoveries. The Deep-time Platform is a significant advancement in geoscientific exploration, fostering global collaboration and promoting a data-driven research paradigm within the framework of open science.
A new publically available dataset of global seasonal prediction of fire danger
Authors: Di Giuseppe Francesca
Published: March 2024

The European Centre for Medium range weather forecast (ECMWF) on behalf of the Copernicus Emergency Management Service (CEMS) has recently widened the fire danger data offering in the Climate Data Store (CDS) to include a set of fire danger forecasts with lead times up to 7 months. The dataset incorporates fire danger indices for three different models developed in Canada, United States and Australia. The indices are calculated using ECMWF Seasonal Forecasting System 5 (SEAS5) and verified against the relevant reanalysis of fire danger based on the ECMWF Re-Analysis (ERA5). The data set is made openly available for the period 1981 to 2023 and will be updated regularly providing a resource to assess the  predictability of fire weather at the seasonal time scale. The data set complements the availability of seasonal forecast provided by the Copernicus Emergency Management Service in real time. A preliminary analysis shows that globally anomalous conditions for fire weather can be predicted with confidence 1 month ahead. In some regions the prediction can extend to 2 months ahead. In most situations beyond this horizon, forecasts do not show more skill than climatology. However an extended predictability window, up to 6-7 months ahead is possible when anomalous fire weather is the results of large scale phenomena such as the El Ni\~no Southern Oscillation and the Indian Ocean Dipole, often conducive of extensive fire burning in regions such as Indonesia and Australia.
An observation-based analysis of hydroxyl radicals in Guangdong, China
Authors: Wei Liyan
Published: March 2024

Hydroxyl radical (OH) is recognized to be one of the most reactive oxidants in the troposphere and plays a critical role in driving the photochemistry of the troposphere. The reactions with OH initiate the oxidation of most trace gases in the troposphere, e.g. NOx and volatile organic compounds (VOCs), which leads to the formation of secondary oxidation products such as ozone (O3) and particular matter (e.g. PM2.5), thus changing the atmospheric composition and affecting the climate. In this study, an observation-based model (OBM) for evaluating the OH concentrations in Guangdong province, China has been developed. We employed the OBM to derive the OH radicals in seven representative districts/cities in Guangdong province from 2015 to 2020. The average OH concentrations in the seven cities gradually increased from an average of (3.3±0.8)×106 cm–3 at 08:00 to (6.7±0.7)×106 cm–3 at 13:00 local time. The OH concentrations derived by the OBM were found in reasonable agreement with previous observations as well as modeling studies in Guangdong. In addition, the average OH concentrations derived by the OBM method in the seven cities in Guangdong Province were about five times higher than those in clean background regions such as the Amazonas, Brazil, and pre-industrial Guangdong province. This is a highly significant point in terms of the impacts of the changing OH on the atmospheric capacity and chemical composition, which can have detrimental effects on human health, ecosystem and the climate.
Compounding preconditions leading to wildfires differ across European climate regions
Authors: Miller Julia , Macakova Michaela , Touma Danielle , Brunner Manuela
Published: March 2024

Recent wildfire seasons broke records in terms of severity and damage in different regions of the world, e.g. in California in 2021 and in Southern Europe in 2022. The  probability of such severe and large wildfires is enhanced by compounding meteorological conditions of hot, dry and windy weather, which lead to dry fuels supporting the spread of fires. Drivers of low-frequency but high-impact fire events operate on different spatio-temporal scales and are difficult to identify with classical regression methods. Here, we use causal inference methods to describe the relationships between different variables driving fires and quantify their effect on the occurrence of fire events. We examine hydro-meteorological and land-surface drivers of wildfires in different European climate regions by leveraging ESAs’ FireCCI burnt area product together with CERRA reanalysis data from 2002 to 2022. Our results show region-specific patterns of the different variables prior to the wildfire events, which allow us to identify different wildfire pre-condition types. Highlighting the spatial variability of different wildfire drivers in various climate regions of Europe provides valuable insights for the development of targeted fire prevention measures and management. 
On the physical meaning of geodetic networks’ over-constraints solutions
Authors: Ampatzidis Dimitrios , Balidakis Kyriakos , Tsimerikas Alexandros
Published: March 2024

It is widely known that the geodetic networks (both terrestrial and space) suffer from the so-called rank deficiency. This is the algebraic expression of the weakness of the observations to sense all the necessary information for the reference system definition (in terms of origin scale and orientation). For example, the SLR technique is sensitive to the origin and scale, while the orientation can be only externally defined. On the other hand, the traditional quasar-based VLBI does not sense either origin and orientation but only scale.In general, the rank deficiency is remedied by the use of the so-called constraints. The constraints can be divided into two major categories: a. The minimum constraints, where they just treat the rank deficiency problem (as the word minimum dictates) and do not interfere with the shape of the network, and b. the over-constraints, which do not only solve the rank deficiency but alter the shape of the geodetic network.While the minimum constraint solutions are widely discussed in the geodetic literature, regarding their nature, the over-constraints' physical meaning is not so clear (if not vague). The present study aims to provide a physical meaning of the over-constraints solution, under the prism of its stochastic interpretation.
Design, operation, and insights from Zürich city's mid- and low-cost CO2 sensor network
Authors: Grange Stuart K. , Rubli Pascal , Fischer Andrea , Hueglin Christoph , Ponomarev Nikolai , Brunner Dominik , Emmenegger Lukas
Published: March 2024

As a part of the ICOS Cities project, a dense CO2 sensor network was deployed across Zürich city in July 2022 that will remain operational until July 2024. The network comprises 250 NDIR (nondispersive infrared) CO2 sensors from three manufacturers (Senseair, Vaisala, and Licor) at 87 monitoring sites. The sensors can be classified into low- and mid-cost groups (~€500 and ~€7000 respectively). Most mid-cost sensors were installed with rooftop inlets, while most low-cost sensors were deployed near ground level, i.e. near sources of biogenic activities, human respiration, and fossil fuel burning. All data are transferred using LoRaWan and Picarro CRDS (cavity ring-down spectroscopy) gas analysers with traceable reference gases are used for calibration and the assessment of the sensors’ performance before field deployment.The mid-cost CO2 sensors run on mains power, are placed inside maintenance rooms or measurement cabins, and make use of two calibration gases that are tested daily. After accounting for air pressure, humidity and the reference gas tests, the mid-cost CO2 sensors achieve an accuracy of 1.5 ppm of root mean square error (RMSE) and a mean bias that is within ± 1 ppm when considering hourly means in field conditions. The low-cost sensors are battery-powered and require an initial calibration period to address potential deficiencies with their factory calibration. During field deployment, an algorithm for drift correction is applied that considers meteorological conditions and data provided by the mid-cost sensors in the network. The low-cost sensors achieve a mean RMSE of 15 ppm under field conditions when compared to pseudo-reference time series provided by mid-cost sensors, and on average, they show no systematic bias.The sensor measurement performance is adequate to resolve site-specific differences and interesting source-sink processes – especially those related to traffic and the biosphere. Mean CO2 dry air mole fractions ranged between 432 and 460 ppm across the network with some sites displaying large CO2 diurnal ranges (up to 70 ppm) due to confinement of biogenic emissions in the very early hours of the morning. The network’s background CO2 is highly variable, indicating that Zürich’s ambient CO2 levels are strongly influenced by regional scale processes as well as emissions and sinks within the city’s boundary. In a first attempt to quantify CO2 emissions, the rooftop sensors are combined with inventory data and simulations of biogenic activity using ICON-ART at a spatial resolution of 600 m. In contrast, the low-cost sensors will be employed in combination with highly-resolved urban emission data and GRAMM/GRAL, a building-resolved transport model. In collaboration with the city government, we expect this to become a long-term, actionable contribution to address urban emissions and the city's net-zero commitment.
Water-energy-food nexus in Xinjiang Uygur Autonomous Region: Combined Impact of Climate change and Policies, and potential adaptation pathways 
Authors: Huang Yi
Published: March 2024

Food, energy and water are essential resources for human survival and development, and they are three elements of the 17 UN Sustainable Development Goals (SDGs). Expansion of human activity and climate warming are exacerbating severe risks of water, energy, and food shortages. How to manage the limited resources in an efficient and synergistic manner is essential to achieving sustainable development. Since there are few studies on the Water-energy-food (WEF) nexus for semi-arid regions in northwest China, we took Xinjiang Uygur Autonomous Region (XUAR) as an example to assess the impacts of climate and policies on the water, energy and food sectors in the context of global warming and identify ways to adapt. Firstly, we developed a non-linear system dynamic model to illustrate the interactions between food, energy and water, then 5 scenarios were set up by mainly change food self-sufficiency rate, clean energy use rate and energy intensity, to figure out the impact of different decisions and strategies on WEF nexus from 2020 to 2060, and provide solutions that are conducive to achieve carbon neutrality goal. Finally, we conducted a multi-objective optimization algorithm to attempt to mitigate the conflict between limited resources, socio-economics and a low-carbon environment. The results showed that: (1) The supply and demand for food and energy resources in XUAR showed an increasing trend between 2000 and 2020, while water resources decrease with greater decline on demand side. (2) For every 10% increase in food self-sufficiency, irrigation water, energy demand and carbon emissions will increase by 3.22%, 0.04% and 0.08%, respectively. And every 10% increase in clean electricity usage will cut down water demand and carbon emissions by 8.21% and 8.84%, respectively. (4) Under future water resources conditions, the feasible scenarios can reduce carbon emissions by 79% and enable a 13% reduction in agricultural water consumption comparing to the baseline scenario. Besides, the water stress will switch from very high to very low, which is a qualitative leap in achieving the Sustainable Development Goals (SDGs), especially SDG6 (Clean water and sanitation). To conclude, by reducing the area of cereals, improving irrigation efficiency and increasing the use of clean energy, we can achieve the goal of carbon peak and carbon neutrality, as well as sustainable development.
Increasing cross-border dust weather from Mongolia to China during 1987-2022
Authors: Shi Cuiui , Ma Yihao , Mao Rui
Published: March 2024

Mongolia and northern China have the largest dust weather frequency in Northeast Asia. Dust transport from Mongolia to China is an important cause of dust weather in northern China. In the two dust weather events in April 2023, Mongolia's cross-border transmission accounts for 42% and 62% of dust concentration in northern China respectively. However, there are few studies on the frequency change of cross-border dust weather from Mongolia to China in the past few decades. Based on the observational data, here we analyzed the variation of cross-border dust weather in China and Mongolia during 1987-2022. The result showed that the annual average of cross-border dust weather in China and Mongolia was about 7 times, mostly concentrated in spring. Cross-border dust weather accounts for 75% of the total dust weather in northern China. In addition, cross-border dust weather from Mongolia to China showed an increasing trend in the past 36 years, and the increase was more significant after 2000. The increase in cross-border dust weather from Mongolia to China was influenced by a combination of human activities and the natural environment. Reductions in vegetation cover and soil moisture in Mongolia over the past decades have provided favorable conditions for the dust emission, while changes in the polar front jet have provided the impetus for dust transport. This research contributes to a more comprehensive understanding of the dynamics of dust weather events in Northeast Asia, providing references for future mitigation strategies and environmental management.