bluuebunny/crossref_metadata_2025 huggingface dataset:
Check dam uses for soil conservation and erosion control: a worldwide review
Authors: Lucas-Borja Manuel Esteban , Antonio-Zema Demetrio
Published: February 2023

AbstractThe construction of check dams is one of the most common watershed management tools in degraded catchments. For example, check dams have been used throughout the world for torrent control, water supply enhancement, agricultural land development, and watershed restoration among others. Historically, managers have spent important resources for both maintenance of existing and the construction of new check dams. This contribution presents a comprehensive review related to check dams objectives, functions, effectiveness and undesired effects worldwide. Authors aim to synthesize check dams use and efficacy across the wide range of locations and contexts in which the check dams have been installed. The role of complex interactions between ecological impacts, geomorphic processes and engineering activities is also highlighted. Overall, check dams construction is a widely used tool in degraded catchments, although their efficacy in achieving proposed objectives is often not thoroughly assessed. The authors have identified check dams characteristics and the process feedback loops that these tools initiate across a range of spatial scales and geographic locations.Keywords: Soil erosion, land use change; flooding; watershed management.
Volcano-seismic event classification using wavelet scattering transforms
Authors: Laumann Patrick , Srivastava Nishtha , Li Wei , Ruempker Georg
Published: February 2023

To learn more about the physical processes related to volcanic activity, more and more data from extensive networks of seismic stations is being collected and analyzed. Conventionally, this data is identified and classified manually – a labor-intensive and time-consuming process. Here, we propose a classification method based on the clustering of wavelet scattering transforms of the volcanic events, which are embedded into a lower dimensional space, using t-distributed stochastic neighbor embedding (t-SNE). Wavelet scattering is chosen because of its advantageous properties, such as the invariance of the representation, the high information content, and its stability. For clustering, the spectral clustering method is used. By embedding the data to a pre-trained t-SNE scaffolding a supervised classification method is also possible. For classification, a simple k-nearest neighbor-classifier is used. The method is tested on events from the Llaima volcano in Chile, under supervised and also unsupervised conditions. These lead to promising results with a classification accuracy of 97% in the unsupervised and 99% in the supervised case, respectively.
Mineral-fluid reactivity: The action is at the interface
Authors: Stipp Susan
Published: February 2023

For more than 30,000 years, humans have been able to characterise materials, so they could choose the best for making tools, jewellery, shelter and clothing. For more than 300 years, scientists and craftsmen have known enough about fluids to characterise them and use them, even if they never succeeded in precipitating gold from solutions of lead. However, it has only been the last 30 years that we have been able to characterise the composition and structure of the mineral-fluid interface with techniques that can "see" at the nanometre scale and to simulate interactions from first principals. Once one can understand the mechanisms that control the solid-fluid interface, one can control the material’s properties and its behaviour. This is the key to designer materials and solving challenges in nature.My journey into the nanometre scale world of interfaces began with demonstrating that the surface of a calcite crystal is not simply a termination of the bulk structure. Instead, it is a defect, where the atoms at the interface are restructured. In response to fracture in a vacuum or in contact with gas, water or organic compounds, the atoms of the mineral surface rearrange and the molecules in the fluid in contact organise themselves to delocalise charge differences between each other and with the surface. This plays a role in the behaviour of adsorbates. In turn, ion and organic compound adsorbates can modify surface properties, dramatically changing behaviour, even at tiny fractions of a monolayer. Understanding mineral-fluid-organic compound interactions gives us a powerful tool, the ability to predict behaviour and to control reactions.Work in my group shows that the character of simple organic compounds, i.e. their functional group(s), size and branching, determine their adsorption energy on calcite. Density functional theory simulations match very well with adsorption energy determined with X-ray photoelectron spectroscopy. If we can define such relationships for other mineral systems, it could lead to a whole new conceptual framework for describing and predicting mineral-water-organic compound reactivity.
Strategies for optimizing the scalable microbial synthesis of vivianite
Authors: Eshun Lordina , Coker Victoria , Shaw Sam , Lloyd Jonathan
Published: February 2023

Vivianite (Fe3(PO4)2·8H2O) has been reported to form as a secondary mineralization product during the microbial reduction of phosphate-containing Fe(III) minerals [1 – 3]. The phosphate-rich nature of vivianite makes it a suitable sink for phosphorus, which is a scarce and irreplaceable resource, and a major contributor to eutrophication in surface water bodies. There is, therefore, interest in synthesizing vivianite by Fe(III) reducing bacteria such as Geobacter sulfurreducens and Shewanella putrefaciens, to treat phosphate-rich waters, recovering the phosphate for re-use in agriculture. In this study, factors including the presence and absence of phosphate and electron shuttle, the buffer system, pH, microbial load, and the type of Fe(III)-reducing bacteria that influence the formation of vivianite under laboratory batch systems have been investigated. The rate of Fe(II) production, and its interaction with the residual Fe(III) and other oxyanions (e.g., PO43-, CO32-) was found to be the main driving factor for secondary mineral formation. Magnetite was formed in treatments with zero phosphates whereas vivianite and green rust were formed in treatments containing phosphate. The rate and extent of Fe(III) bioreduction were higher in Shewanella putrefaciens than in Geobacter sulfurreducens. Vivianite and green rust were both identified as the dominant endpoints in treatments with Geobacter sulfurreducens and Shewanella putrefaciens. [1] Fredrickson, Zachara, Kennedy, Dong, Onstott, Hinman, & Li (1998). Geochimica et Cosmochimica Acta 62, 3239-3257.[2] O’Loughlin, Boyanov, Gorski, Scherer, & Kemner (2021). Minerals 11, 149[3] Zachara, Kukkadapu, Fredrickson, Gorby, & Smith (2002). Geomicrobiology Journal 19, 179–207. 
Public health risk assessment of ambient PM2.5-bound toxic heavy metals
Authors: Habib Gazala , Sharma Ashish , Chahal Dinesh , Roy Sayantee , Sinha Baerbel , Chaudhary Pooja , Jahangir Arshid , Raman Ramya Sunder
Published: February 2023

Rapid industrialization and urbanization has caused significant increments in concentrations of particulate matter (PM) bound heavy metals which have adverse effects on human health due to their carcinogenicity. Their exposure may affect reproduction and overall development and may lead to cardio-, haemo-, and neurotoxicity in humans. Despite this, previous studies have not captured the regional differences in air pollution and warrant regional level health effect studies.

To this end, this study aims to assess the health risk assessment of particulate matter (PM2.5) bound heavy metals in the ambient air. Samples are collected from Bikaner for the period of January 2019 to December 2019 during alternate days. Approximate 25 samples of metals are collected from Bikaner city using PM2.5 sampler on an 8-h basis. Samples were analyzed gravimetrically for determining mass content and chemically for determining metal content using Energy Dispersive X-Ray Fluorescence (ED-XRF). PM2.5 exposure assessment is conducted using metal values and associated hazard quotient (HQ). Risk estimates were reported in terms of hazard quotient (defined as ratio of daily inhaled dose to daily acceptable inhaled dose) for exposures of non-carcinogenic metals or lifetime excess risk of cancer (ECR) for exposures of carcinogenic metals. These risks are compared for three contrasting sites including Bikaner, Mohali and Srinagar with Srinagar representative of Himalayan region while Bikaner is indicative of desert region. Dose-response parameters for all metals are adopted from the US EPA database. 

The potential risk due to hypothetical exposure of adults and children to four carcinogenic metals of PM2.5 are expected to be greater than 10-7 showing probability of cancer risks. Among metals, exposure to PM-associated Cd resulted in exposure to PM-associated Cd resulted in consistent cancerous risk in both seasons, whereas exposures to PM-associated Cr resulted in HQ>1 indicating chance of non-carcinogenic risk. This study provides meaningful information about the seasonal variation of PM2.5-linked metals and also explains these in terms of diverse geographical variability of selected sites. Finally, this study provides meaningful insights to design and influence public health policy interventions for PM2.5-borne heavy metal exposures of adults and children for selected sites in India.
Simulation of Future Vegetation Coverage Prediction under Different Development Scenarios in the Tibetan Plateau
Authors: Dong Xiaohua , Gong Chengqi
Published: February 2023

This research utilized GeoSOS-FLUS model to simulate and predict the distribution of vegetation coverage grade in the Tibetan Plateau in the year 2035 under two scenarios: natural development scenario based on historical evolution projection, and ecological protection scenario based on limited transformation policy. First of all, future precipitation and maximum temperature are selected as the main driving factors, supplemented by other factors including relative humidity, sunshine hours, population spatial distribution, slope, slope aspect, elevation, distance to railway and distance to highway, etc.. The vegetation coverage grade of the Tibetan Plateau in 2003 is taken as the base period, and that in 2019 is taken as the end period. Then, a GeoSOS-FLUS prediction model is constructed, based on the cost matrix and neighborhood factors and other related parameters obtained from the two scenarios. Finally, the future vegetation coverage grade distribution in 2035 is predicted by using Markov chain.The results indicated that: ( 1 ) From 1998 to 2019, the bare land of the Tibetan Plateau has the tendency of been transformed into low vegetation coverage, medium vegetation coverage or medium-high vegetation coverage, whereas the area of high vegetation coverage is decreasing.( 2 ) Under the natural development scenario, the areas of the bare land, medium-high and high vegetation coverage of the Tibetan Plateau in 2035 will be reduced by about 2 % compared with the actual vegetation coverage in 2019; the areas of low and medium vegetation coverage will be increased by 2.8 % and 10.3 % respectively. Under this scenario, the vegetation coverage evolution of the Tibetan Plateau bears a positive trend, although the trend will be weakened compared to the historical period.( 3 ) Under the ecological protection scenario, compared with the natural development scenario, the areas of bare land and high vegetation coverage will decrease, and the area of low, medium and medium-high vegetation coverage of the Tibetan Plateau in 2035 will increase. Compared with the results predicted under the natural development scenario, under the ecological protection scenario, the improvement of future vegetation coverage of the Tibetan Plateau is very obvious, and the improvement is mainly contributed by the increase of medium vegetation coverage.
The effect of flow velocity on eDNA and eRNA concentration
Authors: Dercksen Jelle A. , Stancanelli Laura Maria , Blom Astrid
Published: February 2023

Across the globe, freshwater ecosystems have experienced a decline in biodiversity resulting from increasing anthropogenic pressure. Over the past decennia the scientific community has developed new and efficient biomonitoring techniques to register these shifts in biodiversity. A promising technique is the capture and analysis of eDNA and eRNA (environmental DNA and RNA; i.e. eNA). eNA constitutes the genetic material released by a host species into the environment in different forms, such as mucous, skin tissue, scales and saliva. However, in lotic ecosystems, such as streams and rivers, detected eNA concentrations can currently not be translated into the spatial and temporal distribution of the associated species. This is due to the lack of knowledge about the processes (e.g. transport and degradation) that influence eNA presence between the moment of release by its host, and the capture of the eNA by the practitioner.The authors have conducted a set of laboratory experiments to shed light on these processes (i.e. transport and degradation). The objective was to test the influence of flow velocity on concentrations of both eDNA and eRNA. In an annular flume (depth = 19.7 cm; Ø = 3.7 m), which features counter-rotating bottom and top components, we performed eDNA and eRNA degradation experiments under four different flow rates, each with a duration of seven days. The source of eNA originated from water previously inhabited by wildtype zebrafish (Danio rerio). The tested angular velocities of the top lid (νt top lid) are 0.00, 0.35, 1.05 and 1.80 m/s with corresponding velocities of the bottom component in a constant ratio (νt top lid/νt bottom) as to reduce secondary circulations in the cross section of the flume. Flow velocity measurements were taken using an acoustic Doppler velocimeter (ADV) across the depth of the flume. During the experiment, abiotic measurements (of pH, temperature and conductivity) as well as water samples were taken. eDNA and eRNA concentrations (in copy numbers per volume) were gathered from these water samples by means of ddPCR, targeting a species-specific 73 base pair fragment in the Cytochrome c Oxidase subunit 1 gene. The abiotic measurements are consistent over the duration of the experiment (average conductivity of 520.1 µS, average temperature of 20.3 °C, average pH of 8.3). Concerning the eNA results, a decrease in both eDNA and eRNA concentrations can be noted over the span of the experiment regardless of the rotation speed. Additionally, eRNA concentrations generally decreased in concentration at a higher rate than eDNA concentrations. These experiments advance the understanding of eNA degradation in lotic ecosystems, and bring forth new directions of research to improve inference in eNA-based biomonitoring.
Nature-based solutions for flood protection in a systems perspective
Authors: Herman Peter
Published: February 2023

The application of nature-based solutions for flood protection in low-lying coastal areas has recently received much attention. The solution is attractive because it may lower the costs for coastal defense, increase the effectiveness and resilience of defense measures, curb negative trends in biodiversity of globally important animal populations and contribute to carbon capture and storage.Nature-based flood defense measures are based on relatively well-established biogeomorphological principles of self-organisation in coastal landscapes. Vegetated foreshores in particular contribute to wave damping, accumulation and stabilization of sediments maintaining a shallow bathymetry, capacity to adjust bed level to sea level rise and, in some conditions, provision of accommodation space for storm surges. Uncertainties in the contribution of ecosystems to flood safety arise from incomplete modeling capacity for sediment dynamics, inclusion of sub-grid phenomena, complex spatial structure, limited understanding of edge dynamics and sparse knowledge of ecosystem behavior under extreme loading. For application at regional scale, the most difficult problem is that nature-based solutions are needed most where natural processes are weakest, e.g. due to extreme encroachment of the coast.In the broader context of use of nature-based solutions as measure to adapt to increased relative sea level rise, a crucial question is how these solutions will behave at longer term. Geological evidence shows that increased rates of sea level rise forces coastal wetlands to become narrower and to move faster inland. An important factor determining this behavior is the sediment mass balance, inhibiting the vertical rise of an ever-larger surface of marshes with increasing sea level. A second factor is the stability of the seaward edge under conditions of increased wave attack in deeper coastal profiles. These phenomena are observed in contemporary systems with high rates of subsidence.Future-proof nature-based solutions for flood defense will have to resolve the issues related to the regional sediment mass balance and long-term stability of the coastal ecosystems. Whether the strategy is to hold the line of the coast or to withdraw, future coastlines will need sufficient sediment sources, sufficient sediment transport capacity and sufficient ecosystem resilience to provide extended services combining flood defense and biodiversity conservation. Major scientific challenges in the design and use of nature-based solutions are identified at this system scale.
Contrasting weathering dynamics within continents during the past glacial cycles
Authors: Yang Yibo , Galy Albert , Fang Xiaomin
Published: February 2023

Chemical weathering of the continental rocks exerts a dominant force on atmospheric CO2 levels and global climate. How continental weathering works during the Quaternary cooling on glacial-interglacial scales is still poorly understood. Here we reconstructed continental weathering history over the past 800 kyr in a High-Mountain Asia catchment impacted by glaciers. The 87Sr/86Sr ratio of lake water, a proxy of catchment weathering, was lower during interglacials while it was higher during glacials and cold stages of interglacials. This higher level in 87Sr/86Sr ratio is assumed to be caused by a glacier-forced release of radiogenic strontium from reactive minerals.Conversely, 87Sr/86Sr ratio of weathering solution in the Chinese Loess Plateau, a non-glaciated region, displayed lower values during glacials (loess formation) and higher values during interglacials (paleosol formation), which is modulated by temperature dominance of mineral weathering rate. Such contrasting weathering dynamics in glaciated and non-glaciated regions suggest that 87Sr/86Sr ratios of river water delivered into the ocean would be greatly buffered by the contrasting Sr release regimes within continents. This process may limit seawater 87Sr/86Sr variation within a narrow range on glacial-interglacial time scales and provide a novel indicator for tracing the onset of glacial development during the deep past.
Spatial variability and temporal changes of drought generation processes over Europe and the Alps
Authors: Van Loon Anne , Brunner Manuela , Götte Jonas
Published: February 2023

Hydrological extreme events are generated by different sequences of hydro-meteorological drivers, the importance of which may vary within the sample of drought events and in space and time. Here, we investigate how the importance of different hydro-meteorological driver sequences varies by event magnitude, in space, and in time using large samples of catchments in Europe and the Alps. To do so, we develop an automated classification scheme for streamflow drought events, which assigns events to one of eight drought event types - each characterized by a set of single or compounding drivers. Our results show that (1) moderate droughts are mainly driven by rainfall deficits while severe events are mainly driven by snowmelt deficits; (2) rainfall deficit droughts and cold snow season droughts are the dominant drought event type in Western Europe and in Eastern and Northern Europe, respectively; (3) temporal changes in both drought intensity, deficit, and duration and generation processes are stronger in high- than in low-elevation catchments; and (4) in high-elevation catchments, snowmelt-deficit-induced droughts become more frequent, leading to increases in drought deficits. We conclude that climate impact assessments on droughts can profit from assessing changes in drought generation processes to improve the understanding of how drought magnitudes are changing in a warming world.
The SWOT (Surface Water and Ocean Topography) Mission and Its Status
Authors: Fu Lee-Lueng , Pavelsky Tamlin , Morrow Rosemary , Cretaux Jean-Francois , Farrar Tom
Published: February 2023

SWOT is a pathfinder mission using new technology to address transformative questions on energy and water of the Earth System in a warming climate.  The excess heat energy entering the Earth system as a result of the greenhouse effect is largely stored in water, and changes in the water cycle and water resources have profound effects on life on Earth.             SWOT is a next generation radar altimeter that uses synthetic aperture radar interferometry to measure the elevation of water surface over both continents and oceans in two dimensions with a radar footprint 1000 times smaller than that of a conventional altimeter. SWOT will cover the world between 78N and 78S every 21 days, leaving only small gaps comprising <5% of Earth’s surface.  More than 90% of the heat from global warming since the industrial revolution has been absorbed and stored in the ocean.  A major part of this process takes place in the ocean on scales too small to be observed from space in the past.  SWOT will improve the two-dimensional spatial resolution of sea surface height from present 200 km to 20 km to address the processes of heat uptake from the atmosphere. In a warming climate earth’s water cycle is accelerating, making it difficult to track and manage water resources as well as predicting floods and droughts.  The areal extent of surface water on land can be observed by conventional spaceborne sensors, but the volume of surface water in lakes and rivers will be surveyed by SWOT from space for the first time.  The numbers of rivers and lakes to be surveyed by SWOT are orders of magnitude more than the present observations. The high-resolution data of SWOT near the coasts will allow us to study sea level variations in unprecedented detail. Storm surge and other impacts like salt water intrusion and river diversion will be exacerbated by the continuing sea level rise.  SWOT data will help improve models to monitor and forecast these impacts. After nearly 20 years’ development, SWOT was launched on December 16, 2022 as a joint mission of NASA and the French Space Agency, CNES, with contributions from the Canadian Space Agency and the UK Space Agency. The satellite system was fully deployed within a week of launch and is in a 3-month phase of engineering checkout.  A 3-month calibration and validation phase will start afterwards in the one-day repeat initial orbit, which will transition into a 21-day repeat orbit during the science phase of the mission in mid 2023.  The release of SWOT data to the public for evaluation is expected to take place 10 months after launch.  The status of the mission at the end of April will be reported by this presentation.
Ground truth validation of the CMIP energetic particle precipitation forcing
Authors: Kero Antti , Thomas Neethal , Virtanen Ilkka , Verronen Pekka , van de Kamp Max , Nesse Hilde
Published: February 2023

The forcing component of energetic particle precipitation (EPP) is recently added into the IPCC's official Coupled Model Intercomparison Project (CMIP) climate modelling. According to these simulations, the impact of inclusion of the medium energy electrons to the ozone variability was estimated to be 12-24% in the mesosphere and 5-7% in the stratosphere. However, to obtain a continuous particle forcing required for these multi-decadal simulations, the precipitating particle flux spectrum was parameterised by the magnetic Ap index to match statistically to the POES satellite's MEPED particle detector data. This rather simple approach has several uncertainties, but the most critical one is that the existing satellite-borne particle detectors, including the MEPED instrument, struggle to separate the loss cone populations from trapped particles, leading to biases in EPP forcing especially in the relativistic energies.In this presentation, we evaluate various EPP forcing models proposed for the future CMIP climate models against the EISCAT VHF data. This can be regarded as a ground-thruth approach for the mesospheric ionisation essential for the atmospheric consequences of the EPP.
Architecture of intraplate strike-slip fault zones in theYanchang Formation, Southern Ordos Basin, China: Characterizationand implications for their control on hydrocarbon enrichment
Authors: Meng Yujing , Chen Honghan , Luo Yang , Zhao Yanchao , Tang Daqing , He Faqi
Published: February 2023

Previous hydrocarbon exploration in the Ordos, Tarim, and Sichuan basins of China has indicated that strike-slip faults play an important role in controlling reservoir distribution. High hydrocarbon production within strike-slip fault zones in these basins indicates that the fault zones not only act as conduits or seals for hydrocarbon migration, but also provide space for hydrocarbon accumulation. The productivity of different wells, however, can vary within one strike-slip fault zone, suggesting that variability in fault zone architecture controls hydrocarbon enrichment. To date, very few studies have explored fault zone architecture in the southern Ordos Basin, inhibiting oil exploration and development. We explored faults in the Jinghe Oilfield in the southern Ordos Basin by integrating outcrops, wellbore cores, well logs, and 3D seismic data. We carried out fault segmentation, qualitative characterization of fault zone architecture, and quantitative characterization of the boundary between the damage zone and wall rock. The results showed that fault zone architecture is complicated by fault segmentation, architectural configuration, and damage zone asymmetry. Strike-slip faults can be divided into transtensional, strike-slip, and transpressional segments along the fault strike, with transtensional and strike-slip segments dominant in the Jinghe Oilfield. Each segment is further complicated by different configurations of gouge, breccia, and fracture zones along the fault dip. Compared with the strike-slip segments, transtensional and transpressional segments showed more complexity, with the fracture density and damage zone width of the hanging wall being greater than that of the footwall. Transtensional segments with braided and horsetail structures showed more complexity owing to the presence of multiple fault cores and damage zones around the main fault and its subsidiary faults. Quantitative analysis showed that the fault zone width was the greatest for transtensional segments, intermediate for transpressional segments, and the lowest for strike-slip segments. We determined a positive linear relationship between the relative widths of the fault core and fault zone. The cavities in breccia zones and fractures in damage zones provide conduits and storage space for hydrocarbon migration and accumulation. We conclude that damage zones in transtensional segments, particularly in the hanging wall, are primary potential targets for petroleum exploration and development.
A Bayesian Framework for Verifying Methane Inventories and Trends With Atmospheric Methane Data
Authors: Worden John , Pandey Sudhanshu , Zhang Yuzhong , Cusworth Daniel , Zhen Qu , Bloom Anthony , Ma Shuang , Maasakkers Bram , Byrne Brendan , Duren Riley , Crisp David , Gordon Debbie , Jacob Daniel
Published: February 2023

The 2015 Paris Climate Agreement and Global Methane Pledge formalized agreement for countries to report and reduce methane emissions to mitigate near-term climate change. Emission inventories generated through surface activity measurements are reported annually or bi-annually and evaluated periodically through a “Global Stocktake”.  Emissions inverted from atmospheric data support evaluation of reported inventories, but their systematic use is stifled by spatially variable biases from prior errors combined with limited sensitivity of observations to emissions (smoothing error), as-well-as poorly characterized information content. Here, we demonstrate a Bayesian, optimal estimation (OE) algorithm for evaluating a state-of-the-art inventory (EDGAR v6.0) using satellite-based emissions from 2009 to 2018. The OE algorithm quantifies the information content (uncertainty reduction, sectoral attribution, spatial resolution) of the satellite-based emissions and disentangles the effect of smoothing error when comparing to an inventory. We find robust differences between satellite and EDGAR for total livestock, rice, and coal emissions: 14 ± 9, 12 ± 8, -11 ± 6 Tg CH4/yr respectively. EDGAR and satellite agree that livestock emissions are increasing (0.25 to 1.3 Tg CH4/ yr / yr), primarily in the Indo-Pakistan region, sub-tropical Africa, and the Brazilian arc of deforestation; East Asia rice emissions are also increasing, highlighting the importance of agriculture on the atmospheric methane growth rate. In contrast, low information content for the waste and fossil emission trends confounds comparison between EDGAR and satellite;  increased sampling and spatial resolution of satellite observations are therefore needed to evaluate reported changes to emissions in these sectors.
On the structure and variability of vertically propagating marine heatwaves in the Eastern Pacific
Authors: Köhn Eike Eduard , Gruber Nicolas , Münnich Matthias , Vogt Meike
Published: February 2023

In recent decades, the Eastern Pacific has been subject to many pronounced marine heatwaves (MHWs), with far-reaching consequences for marine ecosystems. As MHWs are commonly detected at the sea surface, little is known about their vertical structure, let alone the temporal variability of this structure. To fill this gap, we detect and characterise vertically extended MHWs within a high-resolution model hindcast simulation (1979-2019) of the Eastern Pacific. Considering the vertical dimension in the MHW detection furthermore enables the tracking of vertical MHW propagation. We find that 71% of MHWs are on average confined to the mixed layer, while 29% reach at least 10m below. By clustering the MHWs, we identify four main vertical propagation patterns. While the majority of MHWs remains at the surface throughout their lifetime, 18% (13%) of MHWs subduct beneath (shoal towards) the surface, while 12% rather sit beneath the surface and exhibit multi-surfacing behaviour. As a consequence of the vertical propagation, MHWs affect upper ocean ecosystems substantially longer than diagnosed from the sea surface (40 vs. 30 days on average).In the mid-latitude Northeast Pacific, we find a seasonal cycle in the vertical MHW propagation clusters. We find that wintertime MHWs can detrain from the mixed layer, persist in the seasonal thermocline and re-entrain into the ML at a later stage. This finding agrees well with previous work on the role of the re-emergence phenomenon of sea surface temperature anomalies in the North Pacific and suggests potential sources of predictability for MHWs at the sea surface. At lower latitudes, we find that interannual variability associated with the El Niño-Southern Oscillation strongly dominates any seasonality in the occurrence of the different MHW clusters. Lastly, we find that accounting for the vertical MHW propagation almost doubles the average Eastern Pacific area affected by MHWs, compared to the surface only perspective. These new insights regarding MHW depth structures and their temporal variability mark an important step towards a better understanding of MHW drivers and the consequences of MHWs for marine ecosystems.
Investigating ingestion risks from soils and vegetables grown in urban lead-contaminated soil, and mitigation by soil amendments
Authors: Doherty Rory , Cox Siobhan , Newell Jennifer
Published: February 2023

Community gardens and allotments are being trialled as a nature-based solution to mitigate multiple health and social, economic, and environmental/climate issues in Belfast. However, working in close proximity to urban lead-contaminated soils and ingestion of site-grown produce may pose significant health risks to community members unless remediating action is undertaken. Current research indicates that organic soil amendments adsorb common urban metal contaminants, particularly lead, and thus may limit plant/crop uptake and consequent human health risks after ingestion. This research seeks to investigate health risks associated with ingesting soils and vegetables grown in lead-contaminated and biochar-remediated soils in Lower Botanic Gardens, Belfast, using controlled pot experiments and concurrent field plots. Pots and plots will comprise combinations of high and low lead concentrations in soil, high and low lead concentrations in soil amended with 5%w/w biochar, and seeded with leaf (lettuce), bulb (garlic), and root (carrot) vegetables. Following a standard growth period, the pre- and post-growth soils, and vegetables will be tested using the Unified BARGE Method in vitro bioaccessibility methodology to determine the bioaccessible fraction for lead derived from soils and vegetables with and without biochar remediation. This will then give an indication of ingestion risk associated with biochar-amended and non-amended lead-contaminated soils, and different soil-grown vegetables. It is anticipated that there may be a mild-moderate risk of lead absorption in the gut after ingestion of non-amended contaminated soils; followed by a reduced risk posed by ingestion of site-grown vegetables with a risk hierarchy of carrot > garlic > lettuce; and a further reduced risk from produce grown in biochar-amended soils. These results would support the use of soil amendments to improve the scope of greening nature-based solutions on typically unfeasible contaminated sites, with the ultimate goal of enhancing health and social, economic, and environmental/climate conditions in urban areas.
The paradox of internal phosphorus loading from oxic areas of iron-rich eutrophic boreal lakes: insights from porewater geochemistry
Authors: Jilbert Tom , Zhao Siqi , Hermans Martijn
Published: February 2023

Internal phosphorus (P) loading from sediments is an important component of total P supply to the water column of many eutrophic lakes.  A long-standing paradigm states that the magnitude of internal loading through diffusion of P is limited in the presence of iron (Fe) oxides at the sediment-water-interface, due to efficient sorption and co-precipitation of P with oxide minerals. Iron-rich sediments underlying oxic water columns in shallow lake areas are thus expected to retain, rather than release P. However, recent statistical investigations have suggested that oxic epilimnetic areas of stratifying lakes may be responsible for a significant fraction of the internal P loading in these systems [1], implying a "leaky" seal of Fe oxides even under oxic conditions. Here we study the mechanisms of internal P loading in two Fe-rich eutrophic lakes in southern Finland through geochemical analysis of porewaters, over one annual cycle at five study sites per lake. Diffusive flux calculations using Fick's Law, and upscaling to whole-lake areal estimates, confirm that shallow (approx. <10 m) areas dominate internal P loading even during stratified conditions in summer. Furthermore, the highest instantaneous fluxes of the study were observed in shallow sites in late summer. The results suggest in shallow eutrophic settings with a high organic matter flux to sediments and elevated summer temperatures, remineralization reactions at the sediment-water interface regenerate P efficiently enough to escape capture by Fe oxides, even under sediment molar Fe/P ratios >20.      [1] Tammeorg, O., Möls, T., Niemistö, J., Holmroos, H., & Horppila, J. (2017). The actual role of oxygen deficit in the linkage of the water quality and benthic phosphorus release: potential implications for lake restoration. Science of the Total Environment, 599, 732-738.
Trends in the Frequency and Intensity of Compound Coastal Flooding Events along the Indian coastline during 1980-202
Authors: Dutta Diljit , Srinivas V Vemavarapu , Bala Govindasamy
Published: February 2023

The Bay of Bengal and the Arabian Sea adjoining the coastline of India are breeding grounds for depressions and tropical cyclones, with 2 to 3 cyclones making landfall every year on average. The frequency and intensity of compound coastal flooding events are expected to increase as the world continues to warm. The impact of these events will also be more due to the growing exposure and vulnerability of human settlements in the coastal areas of India. The compound coastal flooding events are primarily driven by extreme sea levels and heavy rainfall during tropical storms and depressions making landfall near the coast. However, there is no comprehensive study on the trends in compound flooding scenarios with reference to Indian coastline. This study presents results from an analysis of compound extreme flood events in the Indian coastal region and assesses the change in frequency and intensity of these events based on in-situ data for the period 1980-2020. The hourly sea-level data was obtained from 9 Tide Gauge stations (TGs) operated by the Survey of India. The daily rainfall data at these stations are extracted from 0.25° resolution gridded rainfall product of the India Meteorological Department (IMD). Harmonic analysis is carried out on the detrended sea-level data to separate the astronomical tide component and obtain skew surge time series at predicted high tide timesteps. The extremes corresponding to 90th, 95th and 98th percentile thresholds are identified for both skew surge and rainfall time series, and the co-occurrence probability of the two extreme events is analysed for the historical data. The evolution of frequency and intensity of the potential compound flood days over the historical period is also investigated.
Distinguishing the impacts of natural and anthropogenic aerosols on global gross primary productivity through diffuse fertilization effect
Authors: Zhou Hao , Yue Xu
Published: February 2023

Aerosols can promote plant photosynthesis by increasing light use efficiency with more diffuse radiation. However, such diffuse fertilization effects (DFEs) vary among different aerosol compositions and sky conditions. Here, we apply a suite of chemical, radiation, and vegetation models in combination with ground- and satellite-based measurements to isolate the impacts of natural and anthropogenic aerosol species on gross primary productivity (GPP) through DFEs from 2001–2014. Globally, aerosols enhance GPP by 8.9 Pg C yr-1 under clear-sky conditions but only 0.95 Pg C yr-1 under all-sky conditions. Anthropogenic aerosols account for 41% of the total GPP enhancement, though they contribute only 25% to the increment of diffuse radiation. For aerosol species, sulfate/nitrate aerosols from anthropogenic sources make dominant contributions of 33% (36 %) to aerosol DFE under all-sky (clear-sky) conditions, followed by the fraction of 18% (22 %) by organic carbon aerosols from natural sources. In contrast to other species, black carbon aerosols reduce global GPP by 0.28 (0.12) Pg C yr-1 owing to large solar light absorptions under all-sky (clear-sky) conditions. Long-term simulations show that aerosol DFE increases 2.9% yr-1 under all-sky conditions mainly because of a downward trend in cloud amount. Our study suggests that the impacts of aerosols and cloud should be considered in projecting future changes of ecosystem productivity under varied emission scenarios.
Modeling of the weighted mean temperature based on the random forest machine learning approach
Authors: Li Qinzheng , Böhm Johannes , Yuan Linguo , Weber Robert
Published: February 2023

Atmospheric weighted mean temperature, Tm, is an important parameter in the Earth’s atmospheric water vapor sounding with the Global Navigation Satellite System (GNSS) technique. In this study, considering spatial distribution, time-varying characteristics, and the correlation with surface meteorological variables, Tm modeling is realized based on the random forest (RF) machine learning and global atmospheric profiles from radiosonde (RS) data and GPS radio occultations (RO) measurements. Comparisons of modeled results and numerical integrations of atmospheric profiles in 2020 show that the RF-based Tm model with surface meteorological parameters generally obtains a good accuracy with overall RMS errors of 2.8 K in comparison with RS data and 2.6 K in contrast to GPS RO data.
Decision-related sensitivity analysis of a flood risk model assessing the benefit-cost ratio of a flood polder at the Bavarian Danube
Authors: Ruf Mara , Hoffmann Amelie , Koutas Daniel , Straub Daniel
Published: February 2023

Floods are one of the most hazardous natural phenomena in Germany, which calls for thorough and comprehensive flood risk mitigation strategies. Considering this, a series of controlled flood detention basins, so-called flood polders, are planned along the Danube as one part of the Bavarian flood protection program 2020plus. By means of a reduction of the peak discharge of large flood events, flood polders can reduce the load on downstream located flood protection structures and therewith lower the probability of dike breaches.A cost-benefit analysis is used to evaluate the economic efficiency of a flood polder location. Therein, the costs of construction and maintenance of the polder are compared with the expected monetarized flood risk reduction over the lifetime of the polder. However, assessing the economic consequences of flood risk on a trans-regional level to quantify the benefit of the flood protection measure is challenging and subject to significant uncertainties. These include uncertainties on the characteristics of the hydrological inputs and their occurrence probability in the future, on the material characteristics and resistances of the dike structures, on population and asset developments, on the economic impacts of flooding, on the discount rate as well as on model choices and simplifications.This highlights the necessity of conducting a thorough uncertainty and sensitivity analysis. Since our model serves to support decision-making, it seems natural that the sensitivity of the benefit-cost ratio to input and model uncertainties should be measured in the context of this decision. Decision sensitivity measures have been proposed [1], however, to our knowledge they have not been applied to the assessment and management of natural hazards. In this contribution, we utilize the expected value of information for sensitivity analysis on the cost-benefit analysis of a flood polder at theDanube River in Bavaria.[1] Felli, J. C., & Hazen, G. B. (1998). Sensitivity Analysis and the Expected Value of PerfectInformation. Medical Decision Making, 18(1), 95–109.
A simple experiment to trace stemflow infiltration and subsurface flow paths based on stable water isotopes
Authors: Marchina Chiara , Zuecco Giulia , Todini Diego
Published: February 2023

Stemflow has a relevant role in forested catchments because it affects the amount of precipitation reaching the soil, and how water infiltrates and interacts with soil particles. The role of stemflow in various subsurface processes depends on the infiltration area and its size is currently a topic of interest and debate within the ecohydrological community. Stemflow infiltration area is generally estimated based on the ratio between stemflow input rate and the mean soil infiltration capacity, whereas direct observations of stemflow infiltration areas are rare. Direct observations of stemflow infiltration areas are usually made by the application of dye tracers, which have proven to be useful for monitoring double-funneling. On the contrary, few direct observations are based on the application of isotopically-labelled water to assess stemflow infiltration area and subsurface flow paths. 
Therefore, in this study, we present a simple experiment carried out in a forested catchment in the Italian pre-Alps to simulate stemflow by using isotopically-labelled water and to quantify stemflow infiltration area and volume. The experiment was conducted during a dry period to observe better changes in the isotopic signal in the soil water. Stemflow was simulated with a rainfall depth and intensity similar to typical summer storms in the catchment, and by using water with an isotopic composition very different compared to the composition of soil water during summer months. The isotopically-labelled water was applied to a beech tree monitored by electrical resistivity tomography during different wetness conditions, as well as during this stemflow experiment.
Soil samples collection for isotopic analysis was carried out after the experiment, at different distances from the stem and at different depths (e.g., 0-15, 15-30, and 30-45 cm). Soil moisture was also measured at 0-6 and 0-12 cm depths at different distances from the stem. Preliminary results showed a rapid infiltration of stemflow along the root system of the beech tree and the usefulness of isotopically-labelled water to simulate stemflow and trace double-funneling.  
Keywords: stable water isotopes; soil water; stemflow; forested catchment.
Morphological evolution of the Hunga Tonga–Hunga Haʻapai submarine volcano after the explosive eruption
Authors: Ribo Marta , Cronin Shane , Stern Sönke , Park Sung-Hyun , Garvin James , Kula Taaniela
Published: February 2023

Submarine eruptions dominate volcanism on Earth, but the recent eruption of Hunga Tonga–Hunga Haʻapai volcano in January 2022 was one of the most explosive eruptions ever recorded. Many large calderas collapse during eruptions and the resulting morphology provides unvaluable information for understanding the processes during highly unpredictable eruptions.Here we present a detailed analyses of the post-eruption morphology of the caldera of the Hunga Tonga–Hunga Haʻapai submarine volcano. We use the first multibeam bathymetry of the caldera, acquired only 5 months after the eruption on the MV Pacific Horizon, in May 2022.The multibeam data shows landslides with 0.5-1 km wide scars, mainly on the southern rim, with the deposits extending to the central part of the caldera. However, the flat inner caldera suggests that most of the material was deposited simultaneously to the caldera drop following the eruption, on the order of 800 m. Sediment cores collected inside the caldera show repeated turbidity current sedimentation pointing to ongoing mass wasting, which could have potentially led to eventual breaching of the rim on the north and east side. Submarine ridges were preserved on these sites, separating the inner caldera and two erosional channels on the outer part, which point to the main debris transport paths during the eruption. More than 50 active gas plumes are observed on the eastern side, located following a straight W-E transect, and on the northern side, where the vents are covering the collapse walls close to the eastern Hunga Tonga–Hunga Haʻapai island. The presence of these vents and their distribution related to the morphology of the caldera, indicate the most energetic parts of the volcano, which can potentially still be hazardous. Our morphological analyses provide new insights of transport and depositional processes following highly energetic submarine eruptions.