bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture porosity and equivalent horizontal permeability computed for shallow-water carbonates of the southern Apennines fold-and-thrust belt, Italy
Authors: Abdallah Ian Bala , Panza Elisa , Dastoli Stefania , Manniello Canio , Prosser Giacomo , Agosta Fabrizio
Published: March 2024

Fracture and fault networks are characterised by complex spatial and dimensional properties that might affect the flow and accumulation of subsurface fluids. In geological applications, DFN models are commonly employed to compute the multiscale properties of fractured rock volumes in terms of porosity and equivalent permeability. In the present contribution, we focus on an outcrop-to-reservoir investigation of Mesozoic shallow-water carbonates exposed along the axial zone of the southern Apennines fold-and-thrust belt, FTB, Italy. The carbonates were originally deposited in lagoon-to-proximal ramp settings of the Paleo Apenninic Platform during Lower Jurassic–Upper Cretaceous times and include well-layered and massive associations of bed packages several m-thick. By integrating the results of both field and digital structural analyses, we build multiple DFNs to assess the hydraulic behaviour of geocellular volumes representative of the different scales of observation, and stochastically populated with high-angle fractures, small, and medium faults. Fractures are either strata-bound, SB, or non-strata-bound, NSB, and results compartmentalized within single-bed packages. Small faults crosscut multiple bed-packages and show a few cm-to-m throws, whereas medium faults displace multiple bed-package associations and have throws > 1m. Both small and medium faults exhibit high peaks of fracture density, P20, and intensity, P21, in correspondence with the releasing jogs disrupting mechanical interfaces such as bed package boundaries and pre-existing low-angle thrust faults. As data input for DFN modeling, the aperture values of the stochastic fractures are set as proportional to either fracture length (most favourable flow conditions) or to the square root of fracture length (least favourable conditions). At the outcrop scale, 5m-side DFN models show the highest values of fracture porosity among those considered in this work. These results are therefore consistent with both SB and NSB fractures forming the main repository for fluid accumulation. At larger scales, the 50m-side and 500m-side DFN models including small and medium faults, are characterized by higher values of equivalent permeability, which range between 10-2 and 10-1 mD. Considering the computed Kxx and Kyy values for the single geocellular volumes, near-isotropic horizontal conditions are assessed across all scales of investigation. Accordingly, altogether, high-angle SB and NSB fractures, small and medium faults form a system of well-connected network through the shallow-water carbonates. Interpreting these data in light of published values for platform carbonates in Italy, we interpret this multiscale horizontal permeability isotropy due to the severe exhumation (~ 4 to 5km) the studied carbonates went through during the Quaternary downfaulting of the southern Apennines FTB.
Anthropocene Under Dark Skies: The Compounding Effects of Nuclear Winter and Overstepped Planetary Boundaries
Authors: Jehn Florian Ulrich
Published: March 2024

The analysis of global catastrophic events often occurs in isolation, simplifying their study. In reality, risks cascade and interact. Therefore, it is essential to consider the interconnected nature of global risks. This investigation explores the interplay between nuclear winter and planetary boundaries. It may seem reasonable to assume that respecting planetary boundaries, which define a safe operating space for the planet, is preferable before a nuclear war. However, that does not always seem to be the case. For instance, increased nitrogen emissions today could serve as a nutrient buffer during nuclear winter. Contrastingly, mitigating climate change, means an even larger temperature drop in nuclear winter in comparison with pre-industrial times. This exploratory study also highlights planetary boundaries that could enhance human survival if we adhere to their limits, both presently and after a nuclear war. The best example being biosphere integrity, as conserving it has no direct downsides and would make the Earth system more resilient to resist the shock of a nuclear winter.
Large-scale Dust-Bioaerosol field observations in East Asia
Authors: Huang Zhongwei , Dong Qing , Xue Fanli , Yu Xinrong , Gu Qianqing , Bi Jianrong , Shi Jinsen , Zhou Tian , Huang Jianping
Published: March 2024

The long-range transport of bioaerosols by dust events significantly impacts ecological and meteorological networks of the atmosphere, biosphere and anthroposphere. Bioaerosols not only cause significant public health risks, but also act as efficient ice nuclei for inducing cloud formation and precipitation in the hydrological cycle. To establish risk management for bioaerosol impacts on the Earth system, a large-scale investigation of bioaerosols must be performed under different environmental conditions. For this purpose, a Dust-Bioaerosol (DuBi) field campaign was conducted, to investigate the distribution of bioaerosols by collecting ~ 950 samples at 39 sites across East Asia from 2016 to 2021. Concentrations and community structures of bioaerosols were further analyzed using fluorescence microscopic observations and high-throughput DNA sequencing, and these factors were compared to environmental factors, such as PM10 and aridity. The results indicated that microbial concentrations at dryland sites were statistically higher than those at humid sites, while the microbe to total particle ratio was statistically lower in drylands than in humid regions. Microbial cells per microgram of PM10 decreased when PM10 increased. The proportion of airborne particles at each site did not vary substantially with season. The richness and diversity of airborne bacteria were significantly higher in drylands than in semiarid regions, while the community structures were stable among all sampling sites. The DuBi field campaign helps a better understanding of bioaerosol characteristics variations along dust transport pathway in East Asia and the changes of bioaerosols under the trend of climate warming, supporting the efforts to reduce public health risks.
Quantifying the anomalous thermal effects of contact aureoles of a large pluton in the Tarim Basin: Constraints from clumped isotope thermometry, in situ calcite U-Pb dating, and zircon U-Th/He thermochronology
Authors: Maimaiti Aizimaiti , Tian Jingqiang , Cong Fuyun , Wang Qi
Published: March 2024

Magmatic activities in sedimentary basins provides abnormal heat sources and exert significant impact on the regional temperature field. In previous studies, the anomalous thermal effects of magmatic activities of multiple scales were studied. Small-scale intrusions (cm-m) can conduct high-temperature thermal baking of surrounding strata within tens to hundreds of meters. Basin-scale heat flow anomalies caused by mantle plume upwelling have also received increasing attention. In contrast, the thermal effects of large igneous plutons (several km to tens of km) have received little attention. A few studies have shown that the large intrusive bodies can affect the temperature field within a range of tens of kilometers. The Permian large igneous province is widely distributed in the Tarim Basin, forming several large plutons. The Manalik pluton is a large intrusive body in the northwestern Tarim, with a long diameter of up to 40 km. We have measured the clumped isotope of different calcite fabrics from the Ordovician carbonate intervals surrounding the contact aureoles of Manalik pluton. In-situ U-Pb dating will be applied to these fabrics to provide starting anchors for thermal history modeling using solid-state reordering models of carbonate clumped isotope. In addition, Silurian sandstones from the same area were collected for zircon (U-Th)/He age measurement and subsequent thermochronological thermal history inversion. Compared with conventional thermal indicators applied in deeply buried strata (e.g., vitrinite reflectance), the integration of the two thermochronological tools (Δ47/U-Pb and zircon U-TH/He) holds the advantage in more accurately quantifying the abnormal thermal effects of kilometer-scale intrusive bodies. The experimental results show that zircon (U-Th)/He and clumped isotope jointly constrain temperatures exceeding 200°C in Well Shengli 1 and Well Yingmai 35, which are closest to the Manalik pluton; the thermal anomalies identified in Well Yudong 2 are as high as 220°C; Well Yingmai 2 Well and Yingmai 34, which are far away from the igneous intrusion, were not affected by the thermal contact aureoles of Manalik pluton during the Permian period, and the current burial temperature is the highest paleogeothermal temperature experienced in historical periods. Based on the zircon (U-Th)/He and U-Pb/Δ47 simulation results, we reveal that the Manalik pluton has a significant thermal baking effect on the area within 20km, and the maximum temperature in the area close to the igneous pluton can exceed 220°C. The results of this study provide typical cases and inspiration for identifying and quantifying the thermal effects of contact aureoles in other basins where large igneous pluton are developed.
Lagrangian characterization of heat waves: The perspective matters
Authors: Mayer Amelie , Wirth Volkmar
Published: March 2024

Atmospheric heat waves pose a threat to natural ecosystems and society, which is projected to become more severe due to anthropogenic global warming. However, the mechanisms that determine the formation of heat waves are not yet sufficiently understood. In particular, there is still quite some debate about the relative contribution of three key processes: horizontal temperature transport, adiabatic heating due to subsidence, and diabatic heating. Here, we quantify these processes from a Lagrangian persepctive using a method that provides essential Lagrangian information about the atmospheric flow on an Eulerian grid. The method is based on the advection of passive tracer fields and includes a relaxation term. For each grid point at any time, the method allows us to decompose a temperature anomaly into the effect of horizontal transport across climatological temperature gradients, the combined effect of vertical transport across climatological temperature gradients and adiabatic heating, and the parcel-based diabatic heating. The tracer method thus provides a field-based view on the three processes under discussion. We analyse several recent heat wave episodes and quantify the contributions from horizontal transport, vertical transport, and diabatic heating. We then continue to analyse whether and to what extent these absolute fields are anomalous with respect to their corresponding climatologies. It turns out that the anomaly-based perspective leads to significant differences regarding the relative importance of the various processes compared to the perspective in terms of absolute fields. Our work complements previous studies based on trajectories, which generally considered significantly fewer air masses and did not take into account a climatological background. The results further our knowledge on important mechanisms and drivers of heat waves, which in turn may help to improve their forecasts.
The joint effects of the boreal summer intraseasonal oscillation and Qinghai-Tibetan Plateau monsoon on the precipitation over Southwestern China 
Authors: Yang Linyun , Chen Haoming , Wang Shuyu
Published: March 2024

This study investigates the influence of the boreal summer intraseasonal oscillation (BSISO) on 10-30-day summer rainfall anomalies in Southwestern China (SWC) under the effects of Qinghai-Tibetan Plateau monsoon (QTPM) based on ERA5 reanalysis data and CN05.1 precipitation in 1981-2018. The results show that the 10-30-day rainfall anomalies in SWC have significant and joint feedback to variation of the second component of BSISO (BSISO2) and QTPM at lagging strong (weak) BSISO events by 0-12 days. Their lagged causal linkage and corresponding physical processes have been revealed by causal effect networks and composite analyses, which are most significant at 4-day and 12-day lag. Simultaneously, BSISO2 can induce wetter 10-30-day rainfall over southern SWC by motivating water vapor transport from the Bay of Bengal towards Yunnan province. More importantly, BSISO2 can modulate a northwest-propagating wave train from the western north Pacific towards SWC at the upper troposphere by vertical wave energy transport, which blocks the wave train propagating from the Lake Balkhash to east China–Japan most significantly at a 4-day lag and leads to drier eastern SWC. The process can be influenced by QTPM significantly which leads to the response of 10-30-day rainfall over SWC with lags of 0-12 days. Specifically, same-phase QTPM can trigger more active wave train propagation from high-latitude while opposite-phase QTPM enhances the low-latitude wave energy transport. The interference then facilitates baroclinic structure over eastern SWC at lagging 12 days with positive precipitation anomalies for same-phase events and negative precipitation for opposite-phase events.
Climate model Selection by Independence, Performance, and Spread (ClimSIPS)
Authors: Merrifield Anna , Brunner Lukas , Lorenz Ruth , Humphrey Vincent , Knutti Reto
Published: March 2024

As the number of models in Coupled Model Intercomparison Project (CMIP) archives increase from generation to generation, there is a pressing need for guidance on how to interpret and best use the abundance of newly available climate information. Users of the latest CMIP6 seeking to draw conclusions about model agreement must contend with an "ensemble of opportunity" containing similar models that appear under different names. Those who used the previous CMIP5 as a basis for downstream applications must filter through hundreds of new CMIP6 simulations to find several best suited to their region, season, and climate horizon of interest. Here, we present methods to address both issues, model dependence and model subselection, to help users previously anchored in CMIP5 to navigate CMIP6 and multi-model ensembles in general. We refine a definition of model dependence based on climate output to designate discrete model families within CMIP5/6. We show that the increased presence of model families in CMIP6 bolsters the upper mode of the ensemble's bimodal effective Equilibrium Climate Sensitivity (ECS) distribution. Accounting for the mismatch in representation between model families and individual model runs shifts the CMIP6 ECS median and 75th percentile down by 0.43˚C, achieving better alignment with CMIP5's ECS distribution. Subsequently, we present a new cost-function minimization-based approach to model subselection, Climate model Selection by Independence, Performance, and Spread (ClimSIPS). We demonstrate ClimSIPS by selecting sets of 2, 3, and 5 CMIP models for European applications, incorporating the new dependence definition along with a performance metric based on agreement with observed mean climate fields and the ensemble spread of projected midcentury change in mean surface air temperature and precipitation. Because different combinations of models are selected by the cost function for different independence, performance, and spread priority balances, we present all selected subsets in ternary contour "subselection triangles". ClimSIPS represents a novel framework to select models in an informed, efficient, and transparent manner and addresses the growing need for guidance and simple tools so those seeking climate services can navigate the increasingly complex CMIP landscape.
Potential of VLBI observations to satellites to estimate orbital elements 
Authors: Wolf Helene , Böhm Johannes , Hugentobler Urs
Published: March 2024

Orbital elements define the shape, size, and orientation of a satellite’s orbit, as well as the position of the orbiting satellite along the ellipse at a specific time. Currently, precise orbit determination relies solely on satellite observations. However, future plans involve equipping Genesis and Galileo satellites with Very Long Baseline Interferometry (VLBI) transmitters. This would enable to observe satellites with VLBI radio telescopes and allow to determine orbital elements from VLBI observations to satellites.This study investigates the potential of VLBI observations to satellites to contribute to the determination of orbital elements. In a first step, schedules, including satellite and quasar observations, are created using VieSched++.  The Vienna VLBI and Satellite Software (VieVS) is used to simulate and analyze these schedules.  To introduce the orbital elements in the Least Squares Adjustment, the partial derivatives of the position vector with respect to the orbital elements are needed. There are different approaches available for computing these partials, including numerical, analytical, or using partials obtained from the ORBGEN module in the Bernese GNSS software.  Next, the partials of the position vector are utilized to determine the partial derivative of the time delay tau with respect to the orbital elements.This enables the estimation of orbital elements from simulated VLBI observations to satellites. The estimated parameters' quality is evaluated based on the mean formal errors and repeatabilities. Furthermore, the correlations between all orbital elements are examined.
A method proposal for spatially-resolved Age of Air from satellitedata
Authors: Voet Florian , Ploeger Felix , Laube Johannes , Preusse Peter , Konopka Paul , Grooß Jens-Uwe , Ungermann Jörn , Sinnhuber Björn-Martin , Höpfner Michael , Funke Bernd , Hegglin Michaela I.
Published: March 2024

The stratospheric overturning meridional circulation is an important element in the global climate system and observationally-based estimates of its strength and changes are important for model validation and process understanding. But such observational constraints are prone to significant uncertainties related to the low circulation velocities and uncertainties in available trace gas measurements. Here, we propose a method to calculate mean age of air, as a measure for the stratospheric circulation, from mixing ratios of multiple measurable trace gas species, like trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), chlorodifluoromethane (HCFC-22), methane (CH4), nitrous oxide (N2O) and sulfur hexafluoride (SF6 ). The method is based on the correlations of these trace gases with mean age. The involved methodological error includes uncertainties due to atmospheric variability and non-compactness of the correlation, and additional instrument uncertainties as would be inherent for e.g. satellite instruments. The age calculation method is evaluated, globally and seasonally, in a model environment and compared against the true model mean age. We show that the tracer-age correlations are, in general, sufficiently compact in the age range between about 1 and 4 to 5 years, depending on the given species. Combination of the six chosen species reduces the resulting uncertainty of the derived mean age to below 0.3 years throughout most regions in the lower stratosphere. Even smaller scale, seasonal features in the global age distribution can be reliably diagnosed from the multi tracer-based mean age. Hence, the proposed mean age calculation method shows promise to reduce the error in mean age estimates from satellite trace gas observations.
Coastal lake records of past tsunamis in South-Central Chile
Authors: Moernaut Jasper , Boes Evelien , Moreno Allende Valentina , Kempf Philipp , Van Daele Maarten , Wils Katleen , Molenaar Ariana , Melnick Daniel , Pino Mario , Urrutia Roberto , De Batist Marc
Published: March 2024

Overlying the subducting Nazca Plate, Chile’s coastline is notoriously prone to megathrust earthquakes and associated tsunamis, as illustrated by the 2010 Maule (Mw 8.8) and 1960 Valdivia (Mw 9.5) events. Despite numerous geophysical and paleoseismic studies, many questions remain about the timing, location and rupture extent of great tsunamigenic earthquakes. To study past tsunami inundation, coastal lakes may form complementary sedimentary archives to classical coastal plain studies as they have more accommodation space and a better preservation potential for tsunami deposits. Moreover, tsunami inundation may lead to prolonged changes in the lake system that are reflected in its sedimentary record. Here we present an overview of published and ongoing research on four coastal lake systems in Chile, i.e. Lake Gemelas West, Lake Huelde, Lake Cucao and Lake Huillinco. Due to their different basin and barrier morphologies, distance to the ocean and temporally-changing ocean connectivity, we expect significant differences in how tsunami inundation is recorded in their sediments. We used the 1960 tsunami deposit in these systems as a reference for which we constrain its sedimentological characteristics and spatial distribution within the lakes. Geochemistry of the pre- and post-1960 sediments is compared based on XRF scans, carbon isotopes and microfacies analysis. This comparison shows that lakes close to the Pacific (i.e. Lake Cucao, Huelde and Gemelas West) contain typical tsunami sands sometimes with mud-rip up clasts, whereas the inland Lake Huillinco exhibits a drastic change in inorganic geochemistry (e.g. a sudden increase in S) that persists until present. We propose that a large amount of salt water propagated in Lake Huillinco, leading to a permanent stratified water body, anoxic bottom water conditions and the preservation of varves. Similar long-lived impacts are also inferred for prehistoric tsunami events in Lake Huelde, where post-tsunami sediments often show varves during a few decades, whereas pre-tsunami sediments are typically homogenous. This study shows that besides tsunami sands, tsunami inundation can also produce long-lived changes in coastal lake systems that are recorded in their sedimentary archive and can be used to infer past tsunami occurrence.
Global estimation of storm surge seasonality and the effect of interannual variability.
Authors: Apolola Ayoola , Ward Philip , Antolínez José , Muis Sanne
Published: March 2024

Extreme storm surges exhibit significant seasonal and interannual variability influenced by large-scale climate modes. The goal of our work is to investigate the seasonality of storm surge extremes and the influence of interannual climate variability at the global scale, which to date is not fully understood due to lack of observations with long-records.  To achieve this goal, we use storm surge levels derived from the Global Tides and Surge Model (GTSM) forced with the extended ERA5 climate reanalysis data spanning 1950-2022. Our methodology consists of two main steps. First, we classify the dataset into four seasons (Winter-DJF, Spring-MAM, Summer-JJA, Autumn-SON) and compute the number of events per season. Next, we conduct extreme value analysis on selected thresholds and explore their connections with climate modes. Preliminary findings indicate that extreme surge events are more frequent and pronounced at higher latitudes during SON, with notable peaks in DJF. This is particularly significant in the North Sea and funnel-shaped coastlines such as Rio de la Plata, Arafura Sea, and Hudson Bay. In contrast, regions like the South China Sea, the Bay of Bengal, the Yellow Sea, and southern Australia experience more frequent surge extremes from JJA to SON with variations in peak season.Equatorial regions, especially around Africa, have negligible surge extremes except for occasional tropical cyclones from late DJF, with peaks in MAM in Mozambique and Madagascar. Similarly, there are occasional tropical cyclone events in parts of the Caribbean with peaks in JJA.The study findings have broader implications for understanding the global distribution and spatio-temporal variation of extreme surge events, which could help to provide guidance on the impacts of climate change in the future. Overall, the preliminary findings underpin the need to further explore what the drivers of storm surge variability are. 
An ancient river disappears in a Mediterranean karst land: the old history of Cana River (Apulia, Southern Italy) 
Authors: Cofano Vito , D'Ettorre Umberto Samuele , Liso Isabella Serena , Capolongo Domenico , Parise Mario
Published: March 2024

Apulia is one of the most interesting karst lands in the Mediterranean area, hosting a variety of distinctive surficial and underground landforms. Among these, polje, a wide and flat depression of tectono-karstic origin, represents one of the most typical epigean landforms in karst. The “Canale di Pirro” polje, located in the central part of Apulia (SE Italy), is the largest in the region (Pisano et al., 2020), bounded on both sides by tectonically-controlled ridges, with an overall length of some 12km and a remarkable underground system of caves, among which there is the deepest of Apulia, where the water table is reached at -264 m from the ground (Parise & Benedetto, 2018). As a karst land, within the polje the water rapidly infiltrates into the ground, making difficult its accumulation at the surface, with the exception of the period of heavy rainfall, when wide sectors of Canale di Pirro become temporary lakes which require several hours to days to be absorbed underground. In ancient documents and maps, with particular regard to historical cartography, the Canale di Pirro polje was drawn as being crossed by a long river, nowadays missing, called Cana (from this river, it seems that the same toponym of the polje took its name). The first written testimonies concern in particular a parchment dating back from the twelfth century; the more recent document we found, still showing the presence of the river, instead, is an ancient map of the nineteenth century. Considering the time span in which Cana River is still represented in historical writings and maps, it is possible to identify its existence between 1195 and 1840, and to hypothesize a presumed coincidance with the Little Ice Age, a climate interval characterized by a long cooling period, especially in the northern hemisphere. In this work, we present a series of historical documents about the existence of the Cana River, collected through literature research, in order to evaluate all the possible causes that led to the river disappearance over the centuries.ReferencesParise M. & Benedetto L. (2018). Surface landforms and speleological investigation for a better understanding of karst hydrogeological processes: a history of research in southeastern Italy. In: Parise M., Gabrovsek F., Kaufmann G. & Ravbar N. (Eds.), Advances in Karst Research: Theory, Fieldwork and Applications. Geological Society, London, Special Publications, 466, p. 137-153, https://doi.org/10.1144/SP466.25.Pisano, L., Zumpano, V., Liso, I. S., & Parise, M. (2020). Geomorphological and structural characterization of the ‘Canale di Pirro’ polje, Apulia (Southern Italy). Journal of Maps, 16(2), 479-487, https://doi.org/10.1080/17445647.2020.1778550.
ROPEWALK (Rescuing Old data with People's Efforts: Weather and climate Archives from LogbooK records) - a digitization project for three centuries of weather observations on board of Danish ships  
Authors: Stendel Martin , Kronegh Adam Jon , Skov Esben Haubro
Published: March 2024

The project ROPEWALK, funded by the AP Møller Mærsk Fund, is a joint initiative of the Danish National Archive and the Danish Meteorological Institute over the period 2023-2026. The aim of the project is to digitize and transcribe all weather observations in ship journals and logbooks stored in the Danish National Archive.A huge amount of data (more than 750 shelf metres) is stored in the archive, beginning as early as the 1680s. With the exception of the Napoleonic wars and the Danish state bankruptcy in 1814, the data is complete. In the archive, logbooks from Danish ships over large parts of Northern Hemisphere are found. Of particular interest are observations from two regions, the Øresund and Greenland:In connection with the Sound duties which every ship passing the sound or belts had to pay between 1426 and 1857, weather observations were made on board of war ships placed at strategic locations near Copenhagen, Helsingør and Nyborg. These ships had to ensure that no one passed without paying the duties. Weather observations on board of these ships were tabulated starting as early as the first half of the 18th century,  and in several cases, observations were conducted every time the ship bell was struck, resulting in as many as 48 observations in the course of one day. For the oldest logbooks, which are in free text rather than in tabular form and go back to the Little Ice Age, we could locate transcriptions which are much easier to read than the original data.The other group of logbooks which are of particular interest are from voyages to the colonies, in particular to (western) Greenland. The Greenlandic Trade Company had a monopoly for commerce with Greenland for nearly 200 years, and foreign ships would not be allowed to call a port. These "Greenland Voyages" were conducted several times per year.In many cases, detailed sea ice observations, both from the Øresund region and the Greenland voyages, have been conducted.The scanning of the original logbooks and journals by the National Archive in highest possible resolution is now almost complete. We have therefore initiated the transcription of the scanned documents by means of machine learning. We will present first results of this analysis.All transcribed data will be made publicly available and can be used for future research or as input for reanalysis projects. 
Efficient spin-up of Earth System Models using sequence acceleration
Authors: Khatiwala Samar , Burke Eleanor
Published: March 2024

The ocean and land carbon cycles plays a critical role in the climate system and are key components of the Earth System Models (ESMs) used to project future changes in the environment. However, their slow adjustment time also hinders effective use of ESMs because of the enormous computational resources required to integrate them to a pre-industrial quasi-equilibrium, a prerequisite for performing any simulations with these models and, in particular, identifying the human impact on climate. Here, a novel solution to this ``spin-up'' problem, regarded as one of the grand challenges in climate science, is shown to accelerate the equilibration of state-of-the-art marine biogeochemical models typical of those embedded in ESMs by over an order of magnitude. Based on a ``sequence acceleration'' method originally developed in the context of electronic structure problems, the new technique can be applied in a ``black box'' fashion to any existing model. Even under the challenging protocols used to spin-up ESMs for the IPCC Coupled Model Intercomparison Project, which can take up to two years on even some of the most powerful supercomputers, the new algorithm can reduce simulation times by a factor of 5, with preliminary results suggesting that complex land surface models can be similarly accelerated. The ability to efficiently spin-up ESMs would enable for the first time a quantification of major parametric uncertainties in these models, lead to more accurate estimates of metrics such as climate sensitivity, and allow increased model resolution beyond what is currently feasible.
Joint inversion of airborne gravity and magnetic data for the crustal structure in central Dronning Maud Land
Authors: Ginga Mikhail , Ebbing Jörg , Ruppel Antonia Stefanie , Läufer Andreas , Eagles Graeme
Published: March 2024

Topography and physical conditions at the base of the Antarctic ice sheet are critical inputs for studies of its present and future ice discharge, and of subglacial geology and hydrology. Airborne gravity and magnetic data, especially when interpreted jointly can help us to link the geology from outcrops towards the coastal areas to unknown subglacial regions further inland. Here we use airborne geophysical data obtained during the joint AWI-BGR campaign WEGAS/GEA between 2015 and 2017 in central Dronning Maud Land (DML) as input for a novel joint inversion scheme. With regard to Gondwana reconstruction, this region is critical because it hosts the ice-covered Forster Magnetic Anomaly, a prominent lineament crossing central DML for some 100s of kilometers south of the main mountain chain. This lineament, originally interpreted as the main pan-African suture of East and West Gondwana, likely represents the eastern margin of Kalahari and its boundary to the Tonian Oceanic Arc Super Terrane (TOAST). In the inversion using the software jif3D, sources of the gravity and magnetic field are combined through a coupling method which decreases the variation of information (VI), so data misfit and model dissimilarity are minimized simultaneously. The model results can be classified in geologically meaningful provinces by applying cluster analysis based on machine learning. Our joint inversion approach improves previous interpretations and sheds light on the crustal architecture of the study area, contributing to further studies on the interaction between the ice sheet and the underlying solid earth.
Comparison of Different Color Space Model's Performance for Estimation of Nitrate and Phosphate in Soil and Water Using A Smartphone-Integrated Imaging Device
Authors: Veerabhadrappa Lavanya , Dey Subhdip , Chakraborty Somsubhra
Published: March 2024

This study introduces a novel smartphone-assisted imaging device for efficient control of agricultural inputs and environmental pollution monitoring by quantifying phosphate (PO43-) and nitrate (NO3–) concentrations in soil and water samples. Utilizing the smartphone's digital camera, the cost-effective and portable device employs standard colorimetric procedures with chromotropic acid and ascorbic acid for NO3– and PO43- detection, respectively. The integrated back camera connects to a handheld system housing ocular sources and optical components, enabling on-the-go measurements. Leveraging the Value (V) component of the HSV color space model, the device estimates NO3– and PO43- concentrations, producing results comparable to laboratory spectrophotometers. Additionally, this study explored RGB, CMYK, and CIELAB color space models, validating the device's effectiveness with 30 soil and 15 water samples. In summary, this user-friendly device offers a reliable, cost-effective solution for measuring NO3– and PO43- levels in soil and water, presenting results comparable to traditional spectrophotometers without the need for laboratory apparatus.Index Terms— soil, water, nitrate, phosphate, smartphone, imaging device, HSV, RGB, CMYK, CIELAB
Amplified upward trend of the joint occurrences of heat and ozone extremes in China over 2013–202
Authors: Xiao Xiang , Xu Yangyang , Zhang Xiaorui , Wang Fan , Lu Xiao , Cai Zongwei , Brasseur Guy , Gao Meng
Published: March 2024

Climate change and air pollution are two intimately interlinked global concerns. The frequency, intensity and duration of heatwaves are projected to increase globally under future climate change. A growing body of evidence indicates that health risks associated with the joint exposure to heatwaves and air pollution can be greater than that due to individual factors. However, the co-occurrences of heat and air pollution extremes in China remain less explored in the observational records. Here we investigate the spatial pattern and temporal trend of frequency, intensity, and duration of co-occurrences of heat and air pollution extremes using China’s nationwide observations of hourly PM2.5 and O3, and the ERA5 reanalysis dataset over 2013–2020. We identify a significant increase in the frequency of co-occurrence of wet-bulb temperature (Tw) and O3 exceedances (beyond a certain predefined threshold), mainly in the Beijing-Tianjin-Hebei (BTH) region (up by 4.7 days decade-1) and the Yangtze River Delta (YRD). In addition, we find that the increasing rate (compared to the average levels during the study period) of joint exceedance is larger than the rate of Tw and O3 itself. For example, Tw and O3 co-extremes increased by 7.0% in BTH, higher than the percentage increase of each at 0.9% and 5.5%, respectively. We identify same amplification for YRD. This ongoing upward trend in the joint occurrence of heat and O3 extremes should be recognized as an emerging environmental issue in China, given the potentially larger compounding impact to public health.
Petrographic and Geochemical Analysis of Upper Cretaceous Phosphorites in Şemikan, Turkey and Gusmari, Albania: Insights into Depositional Environments and Palaeoceanographic Conditions
Authors: Fociro Ana , Öztürk Hüseyin , Sinojmeri Agim , Cansu Zeynep , Moisiu Lavdie , Çelik Yakup , Nazaj Shaqir , Prifti Irakli
Published: March 2024

The Tethyan Phosphogenic Province is one of the widest of its kind, representing an outstanding period of phosphate deposition principally in the Upper Cretaceous-Eocene period. The main aim of this study is to compare the Turkish phosphorites occurring along the southern side of the Neo Tethyan Ocean due to suitable seawater temperature and upwelling oceanic currents with Albanian phosphorites were deposited in higher latitudes and colder climates, in the same ocean. The Şemikan (Türkiye) phosphorites consist mainly of cream-coloured (CCP) and locally reddish phosphorites (RP) occurring as lenses or concordant blankets within high-grade cream phosphorites. Based on microscopic examination, cream-coloured phosphorites consist of phosphatic pellets, intraclasts, bioclasts (fossilized shark teeth, ostracods etc.) and nonphosphatic components, with texture changing from wackestone to packstone, testifying shallow marine depositional environment. Whereas, Gusmari (Albania) phosphorites consist of laminated phosphorites (LP), of mudstone/wackestone texture, with planktonic foraminifera Globotruncanidae, where the phosphate is sedimentary, and alternating laminae of phosphate and pelagic carbonate. Besides this, under SEM-EDS, 5µm crystals of the major ore of uranium, UO2, were evidenced for the first time in LP. The mineralogical analyses showed that the CCP consisted of carbonate-rich fluorapatite, minor calcite and quartz. The RP consisted predominantly of carbonate-rich fluorapatite, hydroxyapatite, montmorillonite, and minor quartz. The LP consisted predominantly of calcite, carbonate-rich fluorapatite, hydroxyapatite, and traces of quartz. The mean P2O5 content of the CCP is 29%, RP and LP 14%, which is lower than that of other well-known global phosphorite deposits. The CaO content of the CCP, RP and LP ore is also higher than that of other global deposits because of a calcite matrix between phosphorite pellets. Based on preliminary results of trace elements CCP, RP and LP show a general trace element scarcity compared to the trace element averages of the world’s average phosphorites. The main reason for this deficiency is the rapid sedimentation or high burial rate in the sedimentary basin, which prevents the replacement of carbonate-rich fluorapatite by trace elements.
Impacts of the uplift of the Pamirs and northern Tibetan Plateau on the aridification of the Taklimakan and Thar deserts since the Miocene
Authors: Sun Hui , Liu Xiaodong
Published: March 2024

The impacts of topographic uplift in different areas of the Tibetan Plateau (TP) on the arid climate and dust cycle in the sandy areas on the north and south sides of the plateau are studied using a regional climate model (RCM) by comparing numerical experiments on the uplift of the Pamirs and the northern TP. Simulation results based on tectonic geological records can be used to explain the differences in drought evolution in different areas around the TP. The results show that: (1) The mechanical blocking effect caused by the uplift of the Pamirs has mainly intensified the aridification and desertification of the Taklimakan Desert since the Pliocene, and its uplift has blocked the water vapor channel in the west side of Tarim Basin, causing a 50% reduction in the annual precipitation (mainly winter precipitation) and a 10-30% increase in the atmospheric dust loading in the Taklimakan Deserts. (2) The uplift of the northern Tibetan Plateau mainly intensifies the aridification of the Thar Desert. The uplift of the northern TP controls the position and intensity of the subtropical high center at 700 hPa in the Thar Desert, causing a 50% reduction in summer and annual precipitation and increase in the atmospheric dust loading in the Thar Desert. (3) The aridification of the Gobi Desert and Loess Plateau since the Miocene is also related to the uplift of the northern TP. The uplifting suppresses the East Asian summer monsoon (EASM), causing a 30-50% reduction in summer precipitation in the Gobi Desert and Loess Plateau. Drought further causes a 10-20% increase in the dust loading in the above areas. (4) In view of the limited geological evidence of remarkable tectonic uplift in the northern TP and the Pamirs since the Miocene and Pliocene respectively and based on the current numerical simulation results, it is speculated that the formation of the Thar Desert should be earlier than the Taklimakan Desert.
Near-Automated Estimate of City Nitrogen Oxides Emissions Applied to South and Southeast Asia
Authors: Marais Eloise , Lu Gongda , Vohra Karn , Horner Rebekah , Zhang Dandan , Martin Randall , Guttikunda Sarath
Published: March 2024

Cities in South and Southeast Asia are developing rapidly, but lack routine, up-to-date, publicly available inventories of air pollutant precursor emissions such as nitrogen oxides (NOx). This data deficiency can be addressed by deriving city NOx emissions from satellite observations of nitrogen dioxide (NO2) tropospheric column densities. In this approach, the city plume is aligned along a consistent direction using wind rotation and a best-fit Gaussian applied to estimate NOx emissions. Issues that impact success of this approach is subjective selection of the sampling area around the city centre and the Gaussian fit often fails or yields physically implausible parameters. Here, we automate this top-down approach by defining many (54) sampling areas that we test with TROPOspheric Monitoring Instrument (TROPOMI) NO2 observations over 19 cities in South and Southeast Asia. Our approach is efficient, adaptable to a wide range of city sizes, eliminates the need for subjective sampling area selection, and increases success of deriving annual emissions from 40-60% with a single sampling area to 100% (all 19 cities) with 54 sampling areas. Annual emissions range from 16±5 mol s-1 for Yangon (Myanmar) to 118±39 mol s-1 for Dhaka (Bangladesh). A widely used global emissions inventory exhibits large (2-fold) discrepancies for 5 of the 19 cities. The increase in success achieved with our updated approach also enables derivation of monthly emissions, although all 12 months are only obtained for one city (Karachi in Pakistan). Seasonality in the monthly emissions matches seasonality in tropospheric column abundances of NO2 and is greater than can be reasoned with seasonality in anthropogenic activity in cities. This suggests that past annual emissions calculated using observations for a portion of the year or select days may be biased. Further refinement of this approach is needed to fully exploit the large sampling density of high-resolution low-Earth orbiting instruments such as TROPOMI and hourly measurements from geostationary instruments such as Geostationary Environmental Monitoring Spectrometer (GEMS), Tropospheric Emissions: Monitoring of Pollution (TEMPO), and Sentinel-4.
Environmental Signatures Preserved In Extremely Shallow-Water Benthic Foraminifera From Oman, Arabian Sea 
Authors: Langer Martin R. , Trubin Iaroslav S. , Kamoun Mohamed
Published: March 2024

Nearshore coastal areas are subject to harsh conditions, being shaped by continuous wave action and exposed to turbulence, erosion, and dynamic processes of sediment reworking. Situated at the interface between land and water, the environmental signatures preserved in microfossil assemblages from coastal environments are often prone to taphonomic alterations, which potentially bias the fossil record and compromise accurate reconstructions. The preservation and composition of microfossil assemblages, however, is of highest importance for paleoenvironmental and paleoclimatic reconstructions.We have analyzed benthic foraminiferal assemblages from a suite of extremely shallow-water habitats along the Dhofar coastline (Oman) to assess their value for paleoenvironmental reconstructions and inferences. Foraminiferal assemblages from these extremely shallow and turbulent water habitats face hostile conditions to their existence and preservation, where the formation of dead assemblages is the result of postmortem processes, among which out-of-habitat transport and the destruction and disintegration of tests are most significant. We examined habitat-specific samples from extreme shallow-water areas to: (1) illustrate and document the species richness and preservation status of foraminiferal assemblages, (2) assess whether the foraminiferal biotas preserve sufficient environmental information to be useful for paleoenvironmental inferences, and (3) provide novel insight into the diversity and composition of benthic foraminifera along the varied habitats of the southern Oman coast. Our analyses show that extremely shallow foraminiferal assemblages from the southern coast of Oman retain the environmental signatures of their habitats despite intense environmental processes, making them useful for paleoenvironmental studies. Features of these signatures are recorded in the structural composition, species richness, dominance, and diversity indices of foraminiferal communities, in addition to numerical abundances of shell preservation groups.
Influence of Arctic sea ice concentration on extreme Ural blocking predictability in subseasonal timescales
Authors: Dai Guokun , Mu Mu , Ma Xueying , Gao Yangjiayi
Published: March 2024

Utilizing the Community Atmospheric Model version 4, the influence of Arctic sea ice concentration (SIC) on the predictability of the Ural Blocking (UB) in subseasonal timescale is investigated. Taking the zonal flows as the reference states, the optimal Arctic SIC perturbations that trigger zonal flows into UB events on subseasonal timescale are obtained with the conditional nonlinear optimal perturbation (CNOP) approach. The numerical results show that the Arctic SIC decline in the Greenland, Barents and Okhotsk Seas can trigger zonal flows into UB events on a timescale of four pentads (20 days). Further diagnosis shows that the SIC decline in these regions locally warms the low troposphere via diabatic processes in the first pentad. Then, dynamic processes, such as temperature advection, modulate the temperature in the middle troposphere and weaken the meridional temperature gradient between the Arctic and mid-latitudes upstream of the Ural sector. The weakened meridional temperature gradient further decelerates the background zonal flow near the Ural sector and triggers UB formation in four pentads. After that, the optimal Arctic SIC perturbations that have great influences on subseasonal UB predictions are also obtained with CNOP approach. It is found that SIC increase in the Greenland Sea, Barents Sea, and Okhotsk Sea would weaken the UB intensity while SIC decline in these regions would strengthen it. Further diagnoses show that the physical mechanisms are similar to those triggering UB formation. Moreover, utilizing the observing system simulation experiments, it is shown that targeted observations in the Barents Sea, Greenland Sea, and Okhotsk Sea can remarkably improve the prediction skills of UB in the fourth pentad. Numerical results show that targeted observations have a positive effect on 75% of 160 experiment members, reduce 35% forecast errors of the fourth pentad mean blocking index, and perform even better when the original forecast errors are greater. Further diagnosis shows that the improvement is related to the well-described westerly winds in the Ural region and its adjacent regions, corresponding to the more skillful predictions of blocking circulations. The above results supply a theoretical base for the design of Arctic SIC observations and more skillful subseasonal predictions for mid-latitude extreme weather.