bluuebunny/crossref_metadata_2025 huggingface dataset:
Global sensitivity of inundation extent and population exposure to flood magnitude
Authors: Devitt Laura , Neal Jeffrey , Coxon Gemma , Wagener Thorsten , Savage James
Published: February 2023

Assessments of potential future flood hazards under climate change using model cascades are subject to large uncertainties, severely limiting our ability to make robust decisions. The mitigation of impacts of disastrous flood events requires the development of complementary approaches to risk management that can identify exposure of populations and assets across a range of plausible events to derive actionable information under large uncertainty. Therefore, here we provide a high-resolution stress test of the global river network and quantify the sensitivity of inundated areas and population exposure to varying flood event magnitudes for 1.2 million river reaches for the first time. Our analysis reveals regional differences in settlement patterns with respect to flood hazard. We find clear settlement patterns in which floodplains that are most sensitive to flooding from frequent, low magnitudes events have evenly distributed exposure across hazard zones, which suggests that people have found ways to adapt to this risk. In contrast, floodplains most sensitive to extreme magnitudes events have tendency for populations to be most densely settled in these rarely flooded zones, being in significant danger from potentially increasing hazard magnitudes.
Assessing Exposure to Bioaerosols for Public Health Purposes: Turning the micro into the macro.
Authors: Douglas Philippa , Marczylo Emma
Published: February 2023

Bioaerosols are ubiquitous in the environment and are comprised of a complex mix of different species and components of fungi, bacteria, pollen, and viruses. Exposure to some bioaerosols can be beneficial to health, and are an essential part of developing a normal, healthy immune system, whereas others can be detrimental and can cause or exacerbate a plethora of health conditions.Understanding bioaerosol exposure is an essential part of understanding health effects and is often termed the ‘Achilles heel’ of environmental epidemiological studies. However, how do we assess exposure to such a complex mixture of biological matter, which changes spatially and temporally? How do we scale up what we discover at a handful of field sampling locations, or a cell model, to a larger national scale to help decision makers?Here, I plan to present on current progress, gaps and challenges in assessing exposure to bioaerosols, using some past and ongoing work as key examples, and inviting opinions from the audience on how we can work together in the future to address gaps and challenges in this multidisciplinary field.
Hydrological extremes shift controls on and pathways of carbon loss from mountainous watersheds
Authors: Keiluweit Marco , Anderson Cam
Published: February 2023

Floodplain soils within mountainous watersheds are dynamic reservoirs of carbon (C), and experience seasonal flooding due to snowmelt and drainage. Climate change is shifting snowpack levels, making these ecosystems vulnerable to more frequent extreme flood and drought years. Here we show how extreme flooding or drought events, and associated variations in redox conditions, impact the dominant controls on microbial C cycling within and export from floodplain soils. Employing in-field monitoring with advanced analytical and molecular tools in the subalpine East River watershed (Gothic, Colorado) we compared seasonal flooding impacts in extremely low and high river discharge years (2018 and 2019, respectively), foreshadowing climate change projections. Our results show that reduced conditions during flooded periods caused reductive dissolution of Fe oxide minerals, mobilizing previously mineral-bound organic C and enhancing export of dissolved organic carbon (DOC). At the same time, flooding decreased CO2 production and selectively preserved chemically reduced DOC, likely due to metabolic constraints on microbial respiration. Upon drainage and re-oxygenation of floodplain soils, however, CO2 production increased, but was limited by the concurrant entrapment of DOC by newly precipitated Fe oxides within the soils. Compared to the low discharge year, extreme flooding during high dicharge years underminded mineral protection and heightened mineral constraints, suppressing CO2 production and enhanced DOC export from floodplain soils. We conclude that seasonal flooding events shift the relative and interactive impacts of mineral and metabolic constraints on microbial C cycling in floodplains, altering the balance between CO2 and DOC export. Our results suggest that extreme hydrological events expected with climate change will shift the control on and pathways of C loss from floodplains.
A non-smooth cohesive zone model for rock fracture and contact
Authors: Collins-Craft Nicholas , Bourrier Franck , Gaume Johan , Acary Vincent
Published: February 2023

The effect of climate-change driven increases in temperature in high mountain areas is known to enhance the rockfall risk. One of the driving mechanisms is the fracture of rock masses that previously consisted of permafrost, but that are now subject to freeze-thaw cycles. Cohesive zone models are a high-fidelity way of modelling fracture propagation, and in particular extrinsic cohesive zone models are particularly suitable to the task of modelling rock fracture behaviour, as they can capture the full range of fracturing behaviour, from quasi-static to dynamic. As cracks in the field can progress very slowly before reaching a critical point from which they accelerate rapidly, being able to model the full range of crack speeds is essential to accurately capture the physics of rockfall initiation. Here, we propose a non-smooth cohesive zone model that allows us to combine fracture mechanics with contact mechanics, meaning that it is suitable both to model the formation of cracks and the subsequent contact of surfaces as newly formed blocks fall in a unified manner. Further, writing our problem in this way allows us to include frictional behaviour within a monolithic linear complementarity problem, which enables very efficient numerical resolution. We can prove mathematically that the discrete-in-time-and-space problem is well posed for a small enough time-step, meaning that the solution is unique and will not suffer from "solution jumps" (as can happen in quasi-statics). As such, the evolution of the fracture in the rock is continuous, matching the reality, and the shape of the newly-formed rock mass can be accurately captured. Our formulation is also well-adapted for extension to fully-coupled systems that include thermal effects, so as to accurately capture freeze-thaw cycles and properly integrate permafrost behaviour, and thus have a complete model of the system under climate-change-driven loading.
Seasonal and diurnal patterns in Greenhouse Gas fluxes from re-wetted European peatlands
Authors: Boodoo Kyle , Niese Jonas , Herbst Enys , Fischer Katharina , Glatzel Stephan
Published: February 2023

Peatlands represent 2.5% of all agricultural land in the EU, yet they account for ~ 25% of agricultural greenhouse gas (GHG) emissions, and ~ 5% of total EU-wide GHG emissions. Several studies have shown that peatland rewetting can reduce, or even reverse, the net GHG emissions from previously drained peatlands. We investigated GHG emissions from 14 different European peatland sites (Germany [6], Poland [4] and Netherlands [4]) across a landuse (3 levels) and water table (2 levels) gradient during a 2 year period (July 2021 – June 2023). GHG flux measurements utilizing closed, non-flow-through, dark, non-steady-state chambers were implemented to estimate ecosystem respiration from the study sites. Ecosystem respiration represents the largest share of carbon export to the atmosphere from terrestrial ecosystems. Within the study, landuse gradient was represented by the level of paludiculture (harvest frequency/ soil nitrogen levels), and water table level indicated by Typha- and Carex- dominated vegetation. Initial study results indicate that overall, CO2 fluxes varied across seasons (ANOVA, p<0.001, n = 1738, F = 14.08), with the highest fluxes occurring in summer (0.402 ± 0.342 g CO2 m-2h-1), and lowest in winter (0.233 ± 0.368 g CO2 m-2h-1). Similarly, CH4 fluxes varied seasonally, with the highest CH4 fluxes in summer (6.95 ± 8.07 mg CH4 m-2h-1) and lowest in winter (1.98 ± 4.07 mg CH4 m-2h-1). Average CO2 fluxes decreased with the increasing level of paludiculture intensity for both Typha and Carex dominated sites, while CH4 fluxes typically increased with increasing harvest frequency/ soil nitrogen levels. While CO2 and CH4 fluxes were generally higher in the early morning (as compared to afternoons), particularly during summer and autumn, we could not show an overall significant diurnal difference in GHG fluxes. Seasonal variability in CO2 and CH4 was likely an indicator of the effect of temperature and water table level on GHG fluxes. GHG fluxes at the Typha dominated sites were consistently higher than those of complimentary Carex dominated sites for each landuse class, highlighting the importance of water table and vegetation species on GHG emissions. This research was conducted as part of the Peatland Rewetting In Nitrogen-Contaminated Environments: Synergies and trade-offs between biodiversity, climate, water quality & Society (PRINCESS) project, investigating rewetting of drained, nitrogen contaminated peatlands and their potential role in reducing EU-wide greenhouse gas emissions and improving wetland biodiversity.
Storage Potentials for artificial CO2 products in Germany
Authors: Diekmeier Sarah , Reiter Karsten , Friebe Colin
Published: February 2023

To achieve the EU's net zero emissions target in 2050, unconventional measures to remove CO2 from the atmosphere are urgently needed (IPCC, 2016). Due to the very tight remaining CO2 budget, all illustrative model pathways in the IPCC special report on the 1.5°C target assume that net negative emissions must be achieved in the second half of the century. Direct storage of pure carbon dioxide has been investigated and is still applied, but limited depending on the location by restrictive laws, geological availability, and the uncertain long-term safekeeping. The NETPEC project strives to use photo-electro-chemical methods as energy source to produce easily storable, safe and sustainable carbon-sink products. These solid or liquid carbon-rich products can be long-term stored in the underground or at the surface.The aim of the project part, which will be presented, was to create a database containing the storage potentials of Germany with respect to different end products with a large as possible carbon content. Further criteria for the storage sites are a guaranteed safe deposit for at least 1000 years, no negative influence on the surrounding biosphere and its living organisms and no negative interactions between product and repository of any kind. Due to large volumes of production from opencast and mining operations, sites that appear to be suitable in Germany are former open-pit and underground mines. In the case of a fluid product, various underground storage facilities such as hydrocarbon fields and pore storage complexes appear suitable too. In addition, a disposal of solid end products via regular landfills is conceivable. The collected data were provided by the state offices of the federal states and included both legal office maps in raster format which were digitalized and supplemented by other provided or public data as well as shape files with attributes. Depending on the information provided by the states, the database contains the location, the name of the location, owner of the location, area of the location, type of authorization, type of natural resource and for some states also the extracted volumes of the resources.Production quantities and volumes can be used to compare the capacities of potential storage sites with the volume of the CO2 product. As an interim result, both the qualitative opportunities and the quantitative potentials for final repository of solid or liquid carbon-rich product near the surface or underground are shown and illustrate the clearly widely distributed, large potential of the extensive volumes for storage in Germany.
Conceptualization and conditioning of bioenergetic soil organic matter models
Authors: Pagel Holger , Manzoni Stefano , Uksa Marie , Kandeler Ellen , Poll Christian , Song Hyun-Seob , Streck Thilo
Published: February 2023

The turnover and stabilization of soil organic matter (SOM) is the key to highly productive agriculture and to climate change mitigation. The pathways of matter and energy use by soil microorganisms are controlled by their functional traits and interactions. We present the concept of a novel data-driven bioenergetic soil organic matter model and shed light on integrating ecological trait-based ecological frameworks with process-based models. The model links SOM thermodynamics with key microbial traits, corresponding substrate-specific degradation pathways and extracellular enzymatic depolymerization processes. Carbon and energy flows will be quantitatively traced by modeling mass fractions of specific C source pools, C isotopologues and thermodynamic properties (degree of reduction) as dynamic state variables. The model uses functional microbial pools (generalists, specialists and stress tolerators) with specific trait trade-offs to reflect microbial life and growth strategies in line with current ecological theory. We use microbial transition state theory to reflect microbial growth kinetics and test this approach compared to empirical Monod kinetics. Resource use (i.e., enzyme synthesis) is modeled assuming that microbes are naturally selected to maximize their reproductive success (i.e., growth rate). Using a case study, we further demonstrate the applicability of a constraint-based model conditioning method for simulating microbial SOM processing. Based on this, we explain how constraint-based model conditioning could be used to parameterize bioenergetic models for predicting SOM stabilization in agroecosystems.
Filling in the Map: Arctic Ocean mixing space-time geography & its implications
Authors: Waterman Stephanie
Published: February 2023

The rates and mechanisms of ocean mixing are important controls on how the oceans function; yet, our understanding of mixing in the ocean is significantly limited by complex variability in mixing rates and processes and by a scarcity of direct observations. In the Arctic Ocean, the challenges involved in understanding mixing space-time geography and its implications are significant: mixing measurements are especially sparse, and latitude, ice, and stratification make the mixing environment unique. In this talk, I’ll discuss various ways we are mapping Arctic Ocean mixing rates and deriving insights into what sets their variability in space and in time using pan-Arctic measurements from a variety of autonomous instrument platforms and the archived data record. I’ll also show results from our experiments with realistic ocean models to argue that this map matters both to our understanding of Arctic Ocean functioning and our ability to make robust predictions of climate change.
Creating long-term climate data records using transfer functions
Authors: Laeng Alexandra
Published: February 2023

Merging data records from different instruments into a consistent long-term data record is challenging process, especially when the parent datasets have a very short overlap or do not overlap at all. In addition, parent datasets can have different vertical resolutions and temporal and spatial samplings. In these cases, there is a need for a transfer standard - an independent data record that overlaps with parent datasets, allowing to characterize differences between the parent datasets and to derive absolute adjustments. In this study we discuss requirements for the transfer standard including long-term stability, spatial and temporal sampling. We estimate how various properties of the transfer standard affect stability of the merged record and derived long-term trends. We assess the impact of the transfer function on the trends of merged datasets from satellite observations, on the examples of merging ozone records from SAGE II / MIPAS / OMPS NASA and temperature records from HALOE / MIPAS, using EMAC, CMAM and WACCM model fields as transfer standards.
Analysing random spatio-temporal variability of storm events for hydrological modelling
Authors: Rodriguez-Sinobas Leonor , Zubelzu Sergio , Bernal Carlota , Gómez María Teresa , López Santiago Jesús , Zanella Andrea , Bennis Mehdi , Capuzzo Martina , Matendo Sara E. , Ghalkha Abdulmomen , Ben Issaid Chaouki
Published: February 2023

Events-based hydrology phenomena are affected by extreme spatio-temporal variability. Precipitation is the first source of variability. Storms can start at different times across a catchment and can evolve differently over time thus creating a complex frame for events-based hydrological modelling. Both are affected by a random character. On many occasions a scarce number of weather stations are available within the catchments so researchers and hydrologists are forced to use interpolation methods for estimating precipitation. Classical interpolation methods base on deterministic algorithms not properly accounting for the random character of storm. In this work we analyse the spatial variability of the recorded storms in a set of urban weather stations in Madrid delivering some criteria for dealing with spatio-temporal variability of storms for modelling events-based hydrological processes.
Dynamics of Sundarbans mangroves under climate extremes and changing soil nutrient composition
Authors: Chauhan Tejasvi , Ghosh Subimal
Published: February 2023

Mangroves are vital for resilience of coastal communities against climate extremes. They have high carbon densities and sequestration rates which makes them a promising tool for carbon removal from atmosphere using terrestrial vegetation. However, human activities like deforestation and rapid urbanisation pose a major threat to mangroves globally. Sundarbans in South Asia are the largest continuous mangrove forest in the world and due to rampant degradation by human activities, they have been classified as ‘endangered’ under the Red List of Ecosystems. In addition to physical damage to mangroves caused by climate extremes, human activities change the chemical composition of soil leading to changing nutrient availability for mangroves. The ratio of carbon to nitrogen to phosphorous (also called the Redfield ratio) is critical for coastal vegetation productivity and has an optimum value of 106:16:1. While nutrient availability around most mangroves across the globe has changed because of anthropogenic activities, it is projected to further deteriorate in the future augmenting anthropogenic stress on mangroves. The physiological mechanism of mangrove’s resistance to extreme events and changing nutrient supply is poorly understood. The present study fills this gap by advancing our understanding of the dynamics of Sundarbans mangroves in South Asia under climate extremes and changing soil nutrient composition.
Sensitivity analysis of water balance components under climate change in Saxony
Authors: Schuetze Niels , Hauffe Corina , Pahner Sofie , Brandes Clara , Lei Kan , Udo Mellentin
Published: February 2023

Catchments in Saxony differ regarding their physiographic characteristics (topography, geomorphology, geology, land use, soils, etc.) and their climatic boundaries. Both factors influence the flow behavior and the water balance components of catchments. How sensitive the water balance of catchments responds to current and future changes in the climatic boundary conditions is difficult to predict for each catchment and is associated with significant uncertainties. In Saxony, the pronounced drought in groundwater and surface water from 2018 to 2020 led to considerable regional problems in water supply and quality.Schwarze et al. (2017) already investigated trends of the observed discharge and variables derived by hydrograph separation (e.g. baseflow) in a sensitivity study. In this presentation, we show the results of an extension of this analysis with current observation data until 2020. The following research questions are investigated: (i) Are catchments in Saxony already responding to changing climatic conditions? (ii) Which regions show the most significant changes in discharge behavior relative to other water balance components? (iii) What are the factors and drivers of changes in the water balance in Saxonian Catchments?The study is based only on observational data for precipitation, temperature, and discharge in the period of 1961 to 2020 in Saxony. Break point analysis, hydrograph separation, and sensitivity analysis of hydrological signatures are performed for different sets of climate periods to quantify changes and elasticity of the water balance components. As a result, a decreasing trend for the mean flow can be seen for almost all 88 investigated and undisturbed catchments in Saxony. This trend is more pronounced in the mountainous regions than in the lowland of Saxony. Despite the slight increase in the mean annual precipitation, the temperature rise of about one °C from 1991-2020 compared to 1961-1990 in all catchments leads to an increasing evapotranspiration, reduced discharge, and groundwater recharge. References:Schwarze, R., Wagner, M. and Röhm, P. (2017). Adaptation strategies to climate change - Analysis of the sensitivity of water balance variables of Saxon gauge catchments with respect to the increased temperature level from 1988 onwards compared to the reference state of 1961-1987. Ed.: Saxon State Office for Environment, Agriculture and Geology (LfULG), 2017.
Investigation of Spatio-temporal Variation of Ammonia Concentrations in the Dominican Republic
Authors: Tokgoz Seda , Sanlley Carlos A. , Kaynak Burcak
Published: February 2023

Ammonia (NH3) whose main source is agriculture is a reactive and alkaline gas pollutant. Apart from eutrophication and acidification, it contributes to the production of secondary inorganic aerosol. Therefore, it has a significant impact on the ecosystem, air quality. Agriculture, especially activities such as livestock management and fertilizer applications, accounts for 70% of global NH3 emissions, and it is one of the main industries in the Dominican Republic. Ground-based NH3 measurements are not regularly available in the Dominican Republic and globally. No study determined NH3 concentrations using ground-based measurements and satellite retrievals in the Dominican Republic. The aim of this study is to investigate the seasonal and spatial changes of NH3 via all available measurements to understand the source regions.In this study, MetOp (A,B and C) Infrared Atmospheric Sounding Interferometer (IASI) Level 2 NH3 retrievals are used to investigate the NH3 levels in the Dominican Republic. Spatially processed average NH3 retrievals are calculated for the interval between January 2020 and June 2022. Seasonal spatial distributions indicated highest NH3 levels in the fall season, and larger regions with high NH3 levels in the spring season. High average NH3 levels were observed in the northern Cibao region for all seasons. Monte Cristi, Santiago, Espaillat, La Vega, Monseñor Nouel were the main cities with high NH3 levels.In addition to satellite retrievals, limited ground-level biweekly averaged NH3 measurements along with other air pollutants are available via published reports at seven different locations between August 2020 and June 2022. The highest average NH3 concentrations (≥ 56 ppb) are in the two locations at the capital city, Santo Domingo with high urbanization. The third highest location is in Santiago, where high values ​​are also observed in IASI NH3 retrievals. A location in Barahona (southwestern part) has the lowest average NH3 concentration. The spatio-temporal changes over sampling locations via both measurements are examined. Comparison of satellite retrievals with ground-based measurement is performed and correlations are estimated for seven different locations. In addition, average NH3 levels according to land cover will also be examined for three classes: urban, agricultural and forested areas. The results will provide information for future ground-based measurement studies and incorporate remote sensing measurements in assessment where only limited ground-level measurements are available. The findings of this study can also help to understand the role of NH3 for secondary inorganic aerosol formation.Keywords: Ammonia, remote sensing, the Dominican Republic
Channel degradation: sediment transport acceleration of multi-thread gravel bed river after human interventions
Authors: Rusnák Miloš , Kaňuk Ján , Kidová Anna , Lehotský Milan , Sládek Ján , Michaleje Lukáš
Published: February 2023

Freely migrating and dynamic rivers are strongly affected by changing natural conditions in industrial Europe and altered by increasing human pressure on the landscape. Anthropogenic modification, grade-control structures and channelization resulted in channel narrowing, transformation and incision in many rivers in Europe. The Belá river is the last multichannel river system in Slovakia and during the 20th century, systematic regulation and human impact on the environment resulted in rapid channel incision. The channel planform evolution and channel bed changes were analysed in the natural, braided-wandering river system of the Belá river. For spatial-temporal analyses of the channel pattern changes and transformation were used long-term historical aerial data (1949 – 2018; 11 horizons) and high-resolution data were collected from UAV (Unmanned Aerial Vehicle) and TLS (Terrestrial Laser Scanning). Both sources were used for detailed topographic models (including bathymetry) and classified point cloud generation. Lidar dataset combined with a floodplain age map was used for tracking incision intensity during the different time periods and in different river sections.  Sediment supply to the channels correlates with the magnitude of flood events and during the TLS survey from March 2016 to November 2018, 25 964 tonnes of fine-grained sediment were delivered into the river channel. Bed incisions achieve 2.5 m in the last 10 years with the propagation of a knickpoint zone by backward erosion upstream conditioned by the system of cross-valley faults and anthropogenic impact. In 2000, a small hydropower plant was constructed in the position of an old abandoned channel. A rapid incision uncovered a bedrock channel bed formed by a clay sequence of Huty formation (inner-Carpathian Paleogene). The abandoned channel is now used as a supply channel for the hydropower plant and the second natural active channel is artificially maintained by heavy machinery to ensure water supply for the hydropower plant. Human impact disturbed the balance of the sediment system leading to the overall degradation of the channel and loss of ecological functions.
The impact of extreme solar events on the atmosphere
Authors: Reddmann Thomas , Borthakur Monali , Sinnhuber Miriam , Usoskin Ilya , Wissing Jan Maik , Wissing Jan Maik
Published: February 2023

Besides the well-known 11 year solar cycle, the Sun occasionally produces strong eruptions on the Sun‘s surface and in the corona. They can first be seen as flare events in electromagnetic spectrum down to X ray wavelengths. Within these strong eruptions, particles in the solar plasma, mainly protons, are accelerated to high energies that hit the Earth within hours after the event. In addition, plasma clouds can be accelerated and ejected into the interplanetary space and, provided they are directed to the Earth, can cause severe geomagnetic disturbances. This results in a further energetic particle precipitation event a few days after the primary solar eruption. The strength of these events spans orders of magnitude, with the strongest having dramatic impact on the ionosphere and the middle atmosphere affecting even human activities. Here we study the chemical impact and dynamical of solar events on the middle atmosphere which are on the very extreme side but still within the range of a one per millennia event.We first derive a reference example of an extreme solar event from historical records of solar proton events and from analyzed distributions of energy spectra for geomagnetic storms. We then take ionization rates calculated from strong observed events and scale them to represent the extreme events. Finally, we combine the solar proton event with the geomagnetic storm as both events typically impact different parts of the atmosphere. The ionization rates for the extreme event are then used in simulations in the KASIMA and EMAC model which both include energetic particle induced chemistry.In order to represent different dynamical situations in the middle atmosphere which are important for the vertical coupling between the mesosphere-lower thermosphere (MLT) region and the stratosphere we select specific periods of the ERA-Interim dataset with a special focus on sudden stratospheric warmings (SSW) and apply the event for those situations. The simplified production efficiency of NOx and HOx in the models is further compared to an ion chemistry model where the extreme ionization rates are applied. The case of a SSW which shows an elevated stratosphere synchronized with the extreme event is studied in detail as a kind of worst case scenario.
Climate change scenarios for IDF curves for mainland Portugal
Authors: Andrade Cristina , Mourato Sandra , Guimarães Rita , Brandão Claúdia
Published: February 2023

Rainwater drainage systems and other hydraulic infrastructure are scaled considering the intensity of precipitation and its probability of occurrence. The estimation of precipitation intensity through the analysis of the frequency of occurrence of extreme precipitation events is a key instrument for the dimensioning of hydraulic infrastructures and the associated risk of collapse. Sub- or over-estimated rainfall intensities can cause significant problems in various types of hydraulic infrastructures, including flood mitigation and support works due to flooding.The aim of this study is to determine how climate change will influence extreme rainfall and, consequently, the future sizing of hydraulic systems, including rainwater drainage and hydraulic passages. Towards this aim, the Intensity-Duration-Frequency (IDF) curves were computed (durations between 24 and 72 hours), considering the historical period between 1950 and 2001, and for future precipitation projections (ensemble of biased-corrected Regional Climate Models, RCMs). The period 2041‒2070 under the RCP8.5 (Representative Concentration Pathways) and 2071‒2100 under the RCP4.5 and RCP8.5 emission scenarios were analyzed for 25 udometric stations studied in Brandão et al. (2001 and 2004) located in mainland Portugal.Results show an increase in precipitation intensity, however, the differences between the projected IDF and those obtained with observed data (ERA5 dataset) for the 2, 5, 10, 20, 50, and 100 years return periods are not spatially uniform. The outcomes reveal North/South contrasts between the station’s IDFs, being also quite apparent in the influence of the orography.Overall, this study is the first approach to the problem of extreme rainfall in a changing climate, due to the severe consequences of sudden floods and the resilience of territories and their hydraulic infrastructures to these extreme events. Therefore, planning of new policies and the dimensioning of new and existing infrastructures in the medium and long term is thus highly relevant.Acknowledgment: This work was supported by National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020.Keywords: Climate change, IDF curves, Hydraulic passages, Extreme precipitation, Drainage systems, Portugal.
Correction, gap filling and homogenization on daily level of the historical DMI station network temperature data
Authors: Rapp Dina , Møllesøe Vinther Bo , L. Høyer Jacob , Kaas Eigil
Published: February 2023

As climate change is amplified in the Arctic, it is crucial to have temperature records of high temporal resolution and quality in this area. This will help improve understanding of the involved physical mechanisms, assessment of the past changes and improve predictions for the future temperature development in the Arctic. In this study temperature measurements from the DMI Greenland station network spanning 1784-present day are corrected, gap-filled and homogenized on a daily level. Currently homogenized data is only available on a monthly level, and the more recent data has not been homogenized. The data is currently used for purposes like assessment and predictions of the surface mass balance of the Greenland Ice Sheet, temperature/climate reanalyses, validation of proxy data, etc.  This study presents a method for improving the calculation of daily average temperatures, from the current practice of averaging the available measurements without considering what time of day they are from and how the measurements are distributed. The method is based on a moving average taking into consideration time of day, time of year and latitude/longitude of the station in question. An estimate of the related uncertainty is also calculated. Following the generation of daily average temperatures, different gap filling methods are tested. The different algorithms tested and compared are: simple gap filling by linear interpolation with other stations, single station temporal linear interpolation and MEM (Maximum Entropy Method). Finally, homogenization on daily level is performed. These steps will in turn also improve the monthly and annual average temperatures for the DMI Greenland station network. 
The effect of land management on soil organic carbon dynamics along the soil profile in a tropical region (southern Kenya)
Authors: Van de Broek Marijn , Müller Claude , Vanlauwe Bernard , Six Johan
Published: February 2023

While the importance of soil organic carbon (SOC) in the global carbon cycle is well-established, many knowledge gaps remain related to how land management affects changes in SOC stocks, and protection mechanism of SOC. This is particularly the case for the tropics, as is clear from multiple recent meta-analyses on data related to soil biogeochemistry. In addition, while current knowledge on SOC dynamics is derived from the topsoil, studies on how land management affects subsoil OC properties are scarce.Therefore, we studied how two types of land management affect SOC characteristics down to 1 m depth in two locations in southern Kenya. At one location (Embu), the effect of nutrient management on protection mechanisms of SOC is assessed, while at the second location (Mau Forest region) we study the effect of land use changes on soil biogeochemistry. The focus of this study is on assessing how land management affects SOC protection mechanisms (using carbon fractionation) and the contribution of microbial necromass to total SOC (using amino sugar analysis). In addition, multiple other soil properties, including microbial ecology, have been quantified to improve our understanding of the effect of land management on subsoil OC dynamics.Using our results, we aim (i) to improve understanding of these processes and (ii) to use this knowledge to improve a mechanistic model simulating soil C and N dynamics along the soil profile.
Drought legacy effects on microbial community structure in a managed grassland
Authors: Schmidt Hannes , Séneca Joana , Canarini Alberto , Simon Eva , Dietrich Marlies , Prommer Judith , Bogdanovic Ivana , Martin Victoria , Mohrlok Moritz , Hausmann Bela , Pötsch Erich , Schaumberger Andreas , Wanek Wolfgang , Bahn Michael , Richter Andreas
Published: February 2023

The last decades were characterized by rising temperatures, enhanced atmospheric CO2 concentrations, and by an increasing frequency of extreme events such as drought. Soil microorganisms are major drivers of biogeochemical processes, yet the effects of climate change in shaping microbial communities remain poorly understood.To address this knowledge gap, we examined how future climate conditions (combined +300 ppm CO2 and +3 °C warming, relative to ambient) and drought, alone and in combination, affect microbial community composition throughout the vegetation period in a sub-montane managed grassland (‘ClimGrass’ experiment; Styria, Austria). We combined amplicon sequencing of bacteria, archaea, and fungi with droplet digital PCR to perform quantitative microbiome profiling of seasonal and drought-legacy effects on soil microbial communities.Drought strongly shaped the bacterial/archaeal and the fungal community structure during peak drought conditions, and this effect could still be detected two and fourteen months after ending drought by rewetting and removing rain-out shelters. In comparison, future climate conditions were observed to exert less pressure on the structure of bacterial/archaeal and fungal communities. Interestingly, abundances of members of Actinobacteria and Bacteroidota for bacteria, as well as Cladosporiaceae and Phaeosphaeriacea for fungi (amongst others) significantly increased during peak drought. Our findings suggest that drought can have immediate and lasting effects on the soil microbial community structure by contributing to the establishment of drought-tolerant microbial communities.
LithoNet: A benchmark dataset for machine learning with digital outcrops
Authors: Thiele Sam , Afifi Ahmed J. , Lorenz Sandra , Tolosana-Delgado Raimon , Kirsch Moritz , Ghamisi Pedram , Gloaguen Richard
Published: February 2023

Deep learning techniques are increasingly used to automatically derive geological maps from digital outcrop models, lessening interpretation time and (ideally) reducing bias. Such techniques are especially needed when hyperspectral images are back-projected to create data-rich ‘hypercloud’ type digital outcrop models. However, accurate validation of these automated mapping approaches is a significant challenge, due to the subjective nature of geological mapping and difficulty collecting quantitative validation data. This makes validation of different machine learning approaches for geological applications exceedingly difficult. Furthermore, many state-of-the-art deep learning methods are limited to 2-D image data, making application to 3-D digital outcrops (e.g., hyperclouds) an outstanding challenge. In this contribution we present LithoNet, a benchmark digital outcrop dataset designed to (1) quantitatively compare learning approaches for geological mapping, and (2) facilitate the development of new approaches that are compatible with non-structured 3-D data (i.e., point clouds). LithoNet comprises two halves: a set of real digital outcrop models acquired at Corta Atalaya (Spain), attributed with different spectral and ground-truth data, and a synthetic twin that uses latent features in the original datasets to reconstruct realistic spectral data (including sensor noise and processing artifacts) from the ground-truth. We have used these datasets to explore the abilities of different machine learning approaches for automated geological mapping. By making it public we hope to foster the development and adaptation of new machine learning tools.
Remote sensing analysis of Marmolada (Italy) and Juuku pass (Kyrgyzstan) glacier collapses
Authors: Gascoin Simon , Berthier Etienne
Published: February 2023

Summer 2022, in less than a week, two glaciers collapsed. First in Italy on July 3 (Marmolada) then in Kyrgyzstan on July 9 (Juuku pass). The collapse of the Marmolada glacier caused eleven fatalities. In both cases, we immediately requested the tasking of Pléiades satellites to estimate the collapse volumes by photogrammetry. In both cases, the images were acquired three days after the event, and less than one day later we had the first estimates. We found that the Marmolada glacier lost 65,000 ± 10,000 m3. The Jukuu pass glacier lost a volume almost twenty times greater (1,145,000 m3), which remains however much lower than the volumes involved during the collapse of the Aru glaciers on the Tibetan plateau in 2016 (68 and 83 million m3) or the Kolka Glacier in 2002 (130 million m3). From the Marmolada elevation model and orthoimages we could also estimate that the rupture was approximately 80 m wide and 25 m deep.  In the case of the Juuku glacier, the tongue of the glacier collapsed entirely over a width of almost 300 m and the maximum elevation drop reached 50 m.
A single instrument for simultaneous monitoring of greenhouse gases and air pollutants
Authors: Brunner Marco , Hundt Morten , Aseev Oleg
Published: February 2023

Urban air pollution and greenhouse gas emissions are two closely linked problems. They can be attributed to a variety of sources, such as transportation and buildings, waste management and agricultural production, natural events such as forest fires and many others. Monitoring air pollutants and GHG simultaneously with high selectivity and sensitivity enables to detect and evaluate their sources and sinks and to discover the links between them. Precise measurements at various spatial and temporal scales are required for modelling and validation of emission inventories or satellite observations. Solutions to monitor air pollutants or GHG with high precision and temporal resolution were commonly offered as “one-species-one-instrument”, leading to large, immobile measurement setups with high energy consumption. We provide a new compact laser absorption spectrometer that combines several mid-IR lasers. Our solution allows simultaneous high-precision measurements of the greenhouse gases CO2, N2O, H2O and CH4, and the pollutants CO, NO, NO2, O3, SO2 and NH3 within a single instrument and is therefore well suited to detect the relations of the co-emitted pollutants and GHGs.In our contribution, we will demonstrate examples of our instruments’ applications for mobile monitoring of 10 GHGs and air pollutants in urban areas and airborne measurements with airships. Furthermore, we will present the results of parallel monitoring with our instrument and standard conventional gas analysers used for GHG and air pollutant measurements. It demonstrates the ability of our instrument to serve as an all-in-one solution and to replace up to 7 standard gas analysers opening a wide range of new mobile multi-compound gas monitoring applications, for example, in (small) airplanes or cars.
Pebble roundness as a tool to reconstruct fluvial transport distances
Authors: Pokhrel Prakash , Attal Mikael , Sinclair Hugh , Mudd Simon , Naylor Mark
Published: February 2023

Pebbles become rounded during fluvial transport. Roundness, along with other shape factors, size and lithology, are commonly used in sedimentology to link the fluvial transport distance and consequent abrasion prior to deposition. Although roundness is being used as a fundamental property, the method of assessment of roundness is mainly qualitative and there is no model to define the roundness as a proxy of transport distance. Here, we propose a new model that quantifies the relation between roundness and fluvial transport distance, and apply it to pebbles/clasts of multiple lithologies from both modern sediment as well as conglomerates deposited by ancient river system. We collect field data from two Himalayan rivers in Nepal over a length of around 50 km. We use the Isoperimetric Ratio (IR = 4*π*A/P2, where A and P are the cross-sectional area and perimeter of the pebble, respectively) that we correct for the effect of elongation (“Normalized Isoperimetric Ratio - IRn”) to quantify roundness. In the field data, we find a linear relation between IRn and transport distance, with the slope of the line varying with the rock type and percentile considered. Based on these results, we propose a non-linear roundness model, as theory predicts the ratio should asymptotically converge towards a value of 1 (perfectly rounded). This asymptotic behaviour occurs over distances greater than 50 km. Using this new model, we find that the Pliocene conglomerates of the paleo-Bagmati River preserved at the base of the Kathmandu intermontane basin were deposited by a river that was once part of a more expansive river network but has since been a victim of drainage capture.
How much does ice sheet sulfate deposition tell us about volcanic forcing?
Authors: Marshall Lauren , Toohey Matthew , Schmidt Anja
Published: February 2023

Current reconstructions of volcanic forcing over the last 2000 years rely on scaling volcanic sulfate measured in ice cores to estimates of stratospheric sulfate burdens and optical properties using relationships derived from the 1991 eruption of Mt. Pinatubo. However, there are large uncertainties associated with these conversions and consequently a large uncertainty in the reconstructions. Here, we explore the relationship between ice sheet sulfate deposition and volcanic forcing in model simulations of the last millennium conducted using the UK Earth System Model with an interactive stratospheric aerosol scheme. Treating the model sulfate deposition timeseries as a measured ice-core record and using established conversions, we explore how many of the large-magnitude volcanic events simulated in the model are missed by looking at deposition alone, and how the volcanic forcing may be overpredicted or underpredicted compared to the model itself. These results will enable us to further explore uncertainty in these relationships, and aid in improving methods to calculate forcing for past eruptions.
Collision efficiency of poly-dispersed charged spheres settling in a quiescent environment
Authors: Patra Pijush , Roy Anubhab
Published: February 2023

We study the gravity-induced collisions of charged spheres of dielectric materials dispersed in a gaseous medium. When the gap thickness between the surfaces of two spheres is shorter than the mean free path of the surrounding fluid medium, continuum assumptions for the hydrodynamics interactions are no longer valid, and the non-continuum lubrication interactions result in surface-to-surface contact in finite time. Two like-charged dielectric spheres attract each other at close separations for a wide range of size and charge ratio values. We use trajectory analysis to calculate the collision rate and, thus, explore the role of electrostatic interactions on the collision dynamics of a pair of like-charged dielectric spheres. We present the modifications of pair trajectories due to electrostatic forces and show how collision efficiencies vary with the non-dimensional parameter capturing the relative strength of the electrostatic force to gravity as well as the charge ratio and size ratio.