bluuebunny/crossref_metadata_2025 huggingface dataset:
Does climate change science inform England’s local flood risk management strategies?
Authors: Russell Andrew
Published: February 2023

The UK’s flood risk management framework is defined by a complex suite of overlapping legislation, strategies, plans and guidance that each cover different spatial areas (e.g. devolved nations, regions, catchments, local authorities, coastal policy units), timeframes (e.g. short-, medium-, and long-term) and sources of flooding (i.e. river, coastal, surface water and groundwater). This is further complicated by legislation and policies linked to climate change adaptation, land-use planning and environmental protection that cover elements of FRM from different perspectives.

Within this framework, the UK’s statutory climate change advisor – the Committee on Climate Change – has expressed concern about the process of producing and reviewing the 152 Local Flood Risk Management Strategies (LFRMSs) for England that develop the most important actions for managing surface water flooding (SWF).

Here, we present the first analysis of the full suite of LFRMSs and find: 1) the LFRMSs nearly all include good-to-adequate measures to manage SWF; however, 2) less than half consider or acknowledge the different risk profiles that the local areas may face from different climate change scenarios and fewer than 20% of the LFRMSs refer to the UK’s Climate Change Risk Assessment.

We examine and contextualise these results and present recommendations for local authorities to improve the way in which their strategies incorporate climate science.
Seismological station placement in Vukovarsko-srijemska and Osječko-baranjska counties, Croatia: a GIS analysis of environmental noise effects for the CROSSNET project
Authors: Brcković Antonio , Damjanović Vedran , Gašo Valentina , Grljević Stijepo , Kapelj Marko , Kostanjšek Iva , Milec Viktorija , Pervan Marko , Tremljan Anamarija , Fiket Tomislav
Published: February 2023

The Republic of Croatia is a seismically highly active area and is currently insufficiently covered by seismological stations. Due to the shape of Croatia, a dense network of seismological stations is needed for more accurate determination of the magnitude and location of earthquakes. One of the main goals of the CROSSNET Project, which the Croatian Seismological Survey carries out, is to install 95 new seismological stations across the Republic of Croatia.Selection of a site for a seismological station is a complex process that requires careful consideration of a range of factors to ensure that the station is at an optimal location for collecting accurate and reliable data on seismic activity. Field surveys will be required to verify methods used for spatial analysis. The location of the seismological station was chosen based on several factor maps, including natural and anthropogenic noise sources (such as roads, railways, energy infrastructure, industry, and surface waters), geology, and geomorphological criteria (such as slope and aspect).This study aims to find the most appropriate locations for installing a network of seismological stations in Osječko-baranjska and Vukovarsko-srijemska counties in Croatia. It is necessary to set up seismological instruments at locations with reduced seismic noise conditions and favourable geological conditions to improve the quality of the data acquired.Given the large scope of the project and the area it covers, an adequate approach is necessary to plan field investigations; therefore, the Suitability modeller in ESRI software ArcGIS Pro was used to evaluate locations for future field surveys. The suitability modelling identifies relevant criteria (factor maps), prepares criteria data, transforms values for each criterion to a standard suitability scale, weights criteria relative to one another according to their importance, combines the criteria into a suitability map, and finally locates the most suitable areas for field investigations.This work has been fully supported by Next Generation EU and National Recovery and Resilience Plan under project C6.1. R4-I1.
A general view of boreal spring to summer interannual variability: Emergence of evolving tropical Atlantic modes
Authors: Martín-Rey Marta , Pelegri Josep Lluis
Published: February 2023

The Atlantic Meridional Mode (AMM) and Atlantic Zonal Mode (AZM) dominate the boreal spring and summer Tropical Atlantic variability (TAV), respectively, at interannual time scales, with pronounced impacts on the climate of adjacent and remote areas. Previous studies demonstrated the existence of an AMM-AZM connection via ocean wave propagation and modulated by the local wind forcing.Here, we use a novel approach based on Extended Maximum Covariance Analysis (EMCA) to investigate the emergence of evolving spring-to-summer TAV modes in the observational record and its multidecadal modulation. Observational and reanalysis datasets reveal that the first evolving mode corresponds to a basin-wide warming with maximum anomalies over the tropical north Atlantic during boreal spring and equatorial warm conditions in summer season. In contrast, the second evolving mode displays an inter-hemispheric SST gradient during boreal spring that persists until summer months. The first and second evolving modes can be associated with a same-sign and opposite-sign relation between the AMM and AZM, respectively.The expansion coefficients of the evolving modes are positively and negatively correlated at decadal time scales during the observational record, suggesting the emergence of diverse spatial configurations. This multidecadal modulation coincides with different global ocean background states that resemble the Atlantic Multidecadal Variability (AMV) and Pacific Decadal Variability (PDV).To corroborate the above-mentioned observational findings, these results will be compared with those from historical and picontrol simulations from the latest state-of-the-art CMIP6 models.
Timing the collapse of the Atlantic Meridional Overturning Circulation
Authors: Ditlevsen Peter , Ditlevsen Susanne
Published: February 2023

Statistical Early warning signals (EWS) indicate an approach towards a tipping point. These are increased variance (loss of resilience) and increased autocorrelation (critical slow down). The early warning is based on the significance in a linear trend above random fluctuations in the measures. Here we suggest a more rigorous evaluation of the statistics assuming a linear change with time of a control parameter towards a critical value. We calculate explicitly the uncertainty of the EWS as a function of the length of the data window and the time scales involved. This enables us to not only detect a trend but also estimate the timing of the forthcoming collapse.  Ref: Ditlevsen & Ditlevsen: Warning of a forthcoming collapse of the Atlantic meridional overturning circulation, preprint
How asperity size and neighboring segments can change the frictional response and fault slip behavior: insights from laboratory experiments and numerical models
Authors: Corbi Fabio , Mastella Giacomo , Tinti Elisa , Rosenau Matthias , Sandri Laura , Pardo Silvio , Funiciello Francesca
Published: February 2023

Accurate assessment of rate and state friction parameters is essential for producing realistic rupture scenarios and, in turn, for seismic hazard analysis. Those parameters can be directly measured in the laboratory, with experimental apparati that reproduce fault conditions in nature. Alternatively, indirect estimates (i.e., inversion) of rate and state parameters are based on postseismic slip evolution studies and numerical modeling. Both direct and indirect approaches require a series of assumptions that might bias the results.Here we take advantage of a downscaled analog model reproducing experimentally megathrust earthquakes. The analog model shares many characteristics of real subduction zones, although being intentionally oversimplified with respect to nature. This allows reducing the number of potential sources of bias (e.g., fault geometry and asperity size). We perform five analog models with a single, rectangular asperity of different lengths embedded in a nearly velocity neutral matrix. We focus on two different physical conditions, namely the along-strike asperity length and the asperity to neighboring segments length ratio, and study systematically how they tune the model seismic behavior. Then, by coupling quasi-dynamic numerical models with the simulated annealing algorithm, we retrieve rate and state parameters that allow reproducing both the recurrence time, rupture duration and slip amplitude of the analog model, in ensemble. We identify a tradeoff between (a-b) of the asperity and (a-b) of neighboring creeping segments, with multiple combinations that allow mimicking the analog model behavior and variability. We also identify a negative correlation between (a-b) of the asperity and asperity size, with Dc remaining relatively constant within the investigated asperity size range. When estimating (a-b), poorly constrained properties of neighboring segments are responsible for uncertainties in the order of per mille. Roughly one order of magnitude larger uncertainties derive from asperity size. Those results provide a first order assessment of the variability that rate and state friction estimates retrieved for nature conditions might have when used as constraint to model fault slip behavior.
Linear precipitation response to increasingly strong volcanic eruptions and its emergence from internal variability
Authors: Timmreck Claudia , Olonscheck Dirk , Ballinger Andrew , D'Agostino Roberta , Fang Shih-Wei , Hegerl Gabriele , Schurer Andrew
Published: February 2023

Large explosive volcanic eruptions are a potential source of uncertainty in future climate projections as they cannot be predicted in advance, but eventually will occur, causing short-term climatic impacts on both local and global scale. Still, an open topic is the volcanic impact on tropical climate variability, in particular El Niño Southern Oscillation (ENSO) and tropical precipitation and the combined effect of both. Sufficient large ensembles simulations with the same model and radiative forcing scenario but varying initial conditions have become a great tool in recent years to disentangle forced and internal variability).  Here we use the EVA-ENS ensemble (Azoulay et al., 2021) which consists of 100-member ensembles of the MPI-ESM-LR for idealized equatorial Pinatubo-like eruptions of different eruption strength and an additional 100-member ensemble without forcing. We are in particular interested if there is a linear volcanic signal on tropical precipitation dependent on the eruption strength and when did it emerge from tropical internal variability.Our results show that for Idealized tropical eruptions global and large hemispheric mean 2m temperature and precipitation anomalies seemed to be scalable with the sulfur emission strength above a certain threshold, except for tropical temperatures for an emission strength > 40 Tg  sulfur (S). 10 Tg S emission, the upper estimate of the 1991 Pinatubo eruption, seems to be a threshold where the signal is discernible from internal variability. We also find that seasonal and ensemble mean pattern correlation of 2m temperature and precipitation anomalies are highly correlated in particular for larger emission strengths in the tropics and strongly modulated by ENSO.  There is an increasing tendency for a warm ENSO increases with eruption strength. Emergence of the volcanic signal appears for smaller eruption strength when looking to ENSO composites.  Emergence of cooling appears on a hemispheric scale, while precipitation response is more localized and mainly confined to the tropics and subtropics. References:Azoulay, A., Schmidt, H., and Timmreck, C.: The Arctic polar vortex response to volcanic forcing of different strengths, J. Geophys. Res., 126, e2020JD034450, doi.org/10.1029/2020JD034450, 2021.
Investigation of the decay of DOM fraction in soils with different vegetation types by fluorescence and 2D-correlation spectroscopy
Authors: Filep Tibor , Zacháry Dóra , Ringer Marianna , Jakab Gergely , Szalai Zoltán
Published: February 2023

Dissolved organic matter (DOM) fraction of four soils with different vegetation types (grassland, spruce, oak, agricultural) were incubated at 15 °C and the chemical changes of organic matter were monitored by synchronous fluorescence and 2D-correlation spectroscopy. Fluorescence spectroscopy revealed that at the beginning of incubation, on day 3, the proportion of low molecular weight readily biodegradable compounds increases, and from day 8 onwards, the initiated microbial degradation generates a large number of medium molecular weight molecules. At further samplings (days 21, 35 and 60), the proportion of compounds of microbial origin decreases systematically, due to a decrease in microbial activity caused by the lack of substrate. In 2D correlation measurements, we found that the temporal change in spectral ranges was as follows: 250 → 290 → 360 nm. This provides spectroscopic evidence that microorganisms start to consume low molecular weight peptide or sugar-like substances and then release organic matter into the environment through their death and metabolism. At a later stage of incubation, they start to break down the higher molecular weight fulvic acid-like molecules.We concluded that (i) similar patterns emerged in the spectral features of degradation for the four different soils: the dynamics of organic molecules with different size ranges were the same, (ii) a general scheme was found during the decomposition: microorganisms begin to break down the low-molecular-weight organic substances, and then, through their death and metabolism, release organic substances into their environment; finally, in the later stages of mineralization, the higher molecular weight, fulvic acid-like molecules are degraded and (iii) 2D-correlation spectroscopy has proven to be an effective tool for monitoring chemical changes in dissolved organic matter, revealing both simultaneous and sequential chemical events.This work was supported by the Development and Innovation Fund of Hungary [grant No. NKFIH 132191].
Anomalous 2022 deep water formation and intense bloom event in the southeastern Mediterranean Sea
Authors: Teruzzi Anna , Aydogdu Ali , Amadio Carolina , Cossarini Gianpiero , Feudale Laura , Grandi Alessandro , Miraglio Pietro , Pistoia Jenny , Salon Stefano
Published: February 2023

Biogeochemical seasonal cycle in the Mediterranean Sea is characterized by late-winter early-spring phytoplankton blooms driven by vertical mixing events that bring nutrients to surfacelayers. Relatively intense bloom events are usually observed in areas where mixing is strong andpersistent enough to significantly impact concentration of nutrients in surface layers.A markerlymarkedly intense bloom was forecasted in spring 2022 by the Med-MFC system, theproduction center of the Copernicus Marine Service for the Mediterranean Sea, in thesoutheastern basin (in the Cretan area). Thanks to the three-dimensional description of oceanphysical and biogeochemical dynamics at relatively high resolution (1/24°) provided by theMed-MFC system, it has been possible to investigate various elements of the spring 2022 events.In particular chlorophyll was 50% higher than usual, and patches of high chlorophyllconcentration lasted for 3/4 weeks. Comparison with satellite observations confirmed the notableevent and its anomaly with respect to past bloom events in the area. In this work, we investigatethe processes occurring in the area in spring 2022 using physical and biogeochemical Med-MFCproducts as well as available observations. Results show that the spring 2022 event is particularlystrong with respect to climatology of the area and provide indications on the relationshipbetween the bloom and the forcing physical processes, e.g., water mass formation and mixing.Moreover, it has been demonstrated the Med-MFC system capability to monitor in a real timeframework ocean health conditions and extreme marine events in the southeasternMediterranean.
An advanced hybrid-dimensional discrete fracture-matrix model for coupled simulation of water flow and electrical current in variably saturated fractured porous media
Authors: Koohbor Behshad , Fischer Pierre , Fahs Marwan , Younes Anis , Jourde Hervé
Published: February 2023

In the unsaturated zone of fractured and karstified media, although the fractures and incipient karst conduits generally account for a minor volume in the bulk geologic formations, they contribute significantly to the flow and transport properties. The reason is due to the significant difference (i.e., several orders of magnitude) of permeability in comparison with the surrounding porous matrix. Thus, the simulation of groundwater flow in such heterogeneous porous media requires knowledge of geometry and hydrodynamical characteristics of the fractures. However, identifying fractures and incipient karst conduits in the unsaturated zone has been a challenge in hydrogeology. Electrical resistivity tomography (ERT) as a non-invasive geophysical method has the potential to deliver vast information rapidly in a relatively economical way related to fractures and incipient karst conduits. However, the sole use of ERT for the interpretation of geological formation and hydrodynamic properties of fractured domains is not possible as it may lead to ambiguity of interpretations. The main goal of this work is to investigate the performance of coupling water flow and electrical current for fracture characterization. Thus, we develop a new numerical model for the simulation of coupled water flow and electrical current. In this model, the fractures or incipient karst conduits are simulated with the discrete fracture matrix approach which is known to be the most accurate approach for addressing flow in fractured domains as it considers fractures without any simplification. This approach is applied for both electrical current and water flow. The hybrid dimensional approach, which assumes 1D fractures in a 2D porous matrix is used to improve the computational efficiency of the developed model. The partial differential equations describing the flow and electrical current are solved using the mixed hybrid finite element method for space discretization and the method of lines for time integration. These numerical techniques have been selected to ensure an accurate solution to the nonlinear problem in a time-efficient and effective way. The newly developed model is validated for simplified test cases against the results obtained by an equi-dimensional approach based on the conforming finite element method (i.e., using COMSOL Multiphysics®). The effect of major fracture orientation and length on the temporal response of bulk resistivity during a percolation scenario has been studied numerically. In addition, the effect of injection of electrical dipole has been simulated and discussed for the same problem. The results show that the proper placement of the electrical dipole can significantly affect the resolution of the fracture signature response and the bulk resistivity measured on the surface of the domain through time. 
A new atmospheric background state to diagnose local waveguidability
Authors: Polster Christopher , Wirth Volkmar
Published: February 2023

Rossby waveguides constrain the propagation of Rossby waves by ducting eddy activity along paths of enhanced waveguidability in the atmosphere. Conceptually, waveguidability is the property of an eddy-free background state on which waves exist as perturbations. Because eddies are always present in the atmosphere, a procedure is required to separate the waves from the background. The choice of procedure is of practical importance when diagnosing waveguides. For example, a zonal-mean background state is easy to compute from data and often used, but does not allow for longitudinal variation of waveguidability. It has also been shown to exhibit waveguide artifacts in the presence of finite-amplitude eddies.We introduce a new procedure to obtain an eddy-free background state for the analysis of waveguides in the atmosphere. It utilizes a redistribution (so-called zonalization) of Ertel potential vorticity on isentropes to remove eddies, including those of finite amplitude, while retaining local information. Because the procedure can be applied to instantaneous data without a need for temporal aggregation, it is suitable for causal analyses and can be applied to forecast data without lead time restrictions. Our construction is based on the "slowly evolving background state" by Nakamura and Solomon (2011) and Methven and Berrisford (2015), with additions and approximations to achieve a pragmatic compromise between theoretical grounding, usability and ease of computation.The effectiveness of the procedure to meaningfully separate waves and the background state is illustrated with reanalysis data. Rossby waveguides are diagnosed from the background-state PV fields with a gradient-based metric. We show that our localized procedure leads to regional differences in the diagnosed waveguidability and discuss the existence of circumglobal waveguides.
New in situ soil bulk density sensor using gamma radiation
Authors: Pepers Karin , Staats Gijs , Van Egmond Fenny , Koomans Ronald , Teuling Kees , Van Os Gera
Published: February 2023

Soil compaction and soil bulk density are gaining in importance as soil parameters. The standard measurement with rings is labour intensive and therefore expensive. Medusa Explorations developed a sensor for in situ density measurements, the RhoC. This sensor measures in situ a full soil profile of bulk density every 5 cm up to 1 m depth in 15 minutes, without the need to extract a soil core. The measurement uses gamma ray attenuation combined with a soil moisture sensor. A validation study was performed in two locations, on sandy clay loam and sand soil, both with large within field variation in subsoil compaction. The first results show a good correspondence between both methods. Statistical analysis shows a slightly lower precision for the RhoC measurements than for the rings measurements. The results of this validation study will be discussed.
Comparison of urban canopy models (UCMs) over the area of Nicosia
Authors: Vurro Giandomenico , Constantinidou Katiana , Hadjinicolaou Panos
Published: February 2023

Climate change is posing a significant strain on society. The fast urbanization process, in addition to population growth and the constant rise in anthropogenic greenhouse gas emissions, exacerbates climate-induced phenomena. In this background, the EMME region, a climate change hotspot, emerges for its high vulnerability to climate change impacts. Taking advantage of the improvements made in urban parameterization and modeling, and given the lack of works that focus on this region integrating advanced urban parameterization schemes, this work adopts the Weather Research and Forecasting (WRF) model coupled with different urban canopy models (UCMs), to evaluate their performance using Local Climate Zones (LCZs) as land use classification. In particular, we applied three parameterization schemes: 1) Bulk parameterization, 2) Building Effect Parameterization (BEP), and 3) Building Energy Model coupled with BEP (BEP+BEM) over the city of Nicosia (Cyprus) at 1 km2 horizontal resolution for the period 27th of July to 5th of August 2021. This way, we aim to capture a better representation of the finer spatial and temporal distribution of the heatwave that occurred during that period, leading to a peak temperature of 44.3 °C on the 4th of August. These three simulations were compared with observations provided by the Department of Meteorology. The Modified IGBP MODIS-NOAH land use classification is adopted for the whole domain. At the same time, the LCZs classify the land cover into 10 classes based on the urban and thermal features of the Nicosia domain.
North African Humid Periods over the past 800000 years – Timing, Amplitude and Forcing
Authors: Armstrong Edward , Tallavaara Miikka , Hopcroft Peter , Valdes Paul
Published: February 2023

The Sahara region has experienced periodic wet periods over the Quaternary and beyond. These North African Humid Periods (NAHPs) are astronomically paced by precession which controls the position of the African monsoon system. However, most IPCC-class climate models cannot generate enough precipitation to reconcile the magnitude of these events and so the driving mechanisms remain poorly constrained. Here, we present an 800kyr climate dataset produced using a recently developed version of the HadCM3B coupled climate model that simulates 20 NAHPs over the past 800kyr which have good agreement with the timing and amplitude of NAHPs identified in proxy data. Our results confirm that precession determines their pacing, but we identify that their amplitude is strongly linked to eccentricity via its control over ice sheet extent. During glacials, cooling due to enhanced ice-sheet albedo suppresses the amplitude of the NAHPs during periods of precession minima. Our results highlight the importance of both precession and eccentricity, and the role of high latitude processes in determining the timing and amplitude of the NAHPs. This may have implications for the out of Africa dispersal of plants and animals throughout the Quaternary.
Regional transport of air pollutants from stereoscopic remote sensing observation
Authors: Hu Qihou , Zhu Yizhi , Zhang Chengxin , Su Wenjing , Ji Xiangguang , Xing Chengzhi , Liu Haoran , Tan Wei , Li Qihua , Liu Cheng
Published: February 2023

  In addition to local emissions and atmospheric chemical reactions, regional transport is also an important source of atmospheric pollutants. Satellite-based remote sensing can obtain the spatial distribution of air pollutants in a large range. However, due to the influence of cloud coverage, there is the problem of data missing, which make it difficult to directly use satellite data for quantitative assessment of regional transport. In this study, we used satellite remote sensing from TROPOMI to update the emissions of WRF-Chem modeling. Then, the spatial distribution of regional transport fluxes was obtained through the updated modeling, and the output areas of air pollutants were identified in a large range of regional pollution events. We find that with the overall improvement of air quality in the Beijing-Tianjin-Hebei region, the contribution of external input to air pollution in Beijing from surrounding cities shows a downward trend, while the impact of local emissions become more prominent. Besides, the transports through elevated altitude were investigated through ground-based remote sensing. We found that the transport heights and source regions for different pollutants are quite different. Aerosols and sulfur dioxide (SO2) are significantly affected by the long-distance transport across the upper boundary layer; nitrogen dioxide (NO2) is mainly from local emissions and transport from surrounding area across the lower boundary layer; while the regional transport of formaldehyde (HCHO) is not obvious. Moreover, regional transport through elevated altitudes not only directly brings air pollutants, but also can cause the inversion of the vertical structure of aerosols. The inverse structure of aerosols can further induce adverse meteorological conditions through the interaction between pollution and meteorology, and then aggravate air pollution.
Tracking a decade of hydro-geological emergencies in Italy and their interplay with urban expansion
Authors: Gatto Alessio , Martellozzo Federico , Clo' Stefano , Segoni Samuele
Published: February 2023

Climate change and urban expansion are contributing to a considerable increase in catastrophic atmospheric and hydro-geological events, which cause significant damage to the urban and social fabric.This work takes Italy as a nation-wide case of study with a twofold objective: first, we compiled a dataset of recent hydro-geological disasters for which a state of emergency was declared; second, we focused on the interconnections between urban expansion and occurrence of disasters at the municipality level.The dataset was built thanks to the collaboration with the Italian National Civil Protection Department, from which the data relating to national states of emergency and the surveys carried out were obtained. We discovered that in Italy, during the last ten years, there had been more than one hundred events that have required the intervention of national Civil Protection, with the declaration of the national state of emergency and the funding of interventions for first aid and restoration. The dataset consists of sets of municipalities and provinces that were included in the national state of emergency that suffered damage and obtained subsidies for reconstruction. Furthermore, information was collected regarding the beginning and end of the state of emergency, the days on which the event occurred, and the funds disbursed for recovery.This database was the basis for subsequent analyses (at the municipality level and at the province level) aimed at quantifying the correlations between the occurrence of disasters and state-of-the-art indicators like soil consumption, extension of mapped hazardous zones, and buildings in areas at risk.
Assessing water observation network settings by hydro-geological sub-sampling of a large data set for Sweden
Authors: Gute Ellen , Ickes Luisa , Pechlivanidis Ilias
Published: February 2023

Developing cost-effective methods for hydrological observations is an identified research objective of the WMO Hydrological Research Strategy 2022-2030. Network settings of hydrological observational networks are central for data collection and monitoring efforts to fulfill observation needs. In this work, we ask the question: Where and how densely (location and time) measurement stations need to be placed to gain sound scientific insights into hydro-meteorological conditions of a region?  

We address this question through information theory concepts and calculate entropy, joint entropy, and mutual information for an existing large dataset of hydro-meteorological parameters. The dataset spans 36 years (1981-2017) of daily data for Sweden based on the national S-HYPE hydrological model. Hydrological data include runoff, inflow, and streamflow as computed values and meteorological data encompass temperature and precipitation as measured and corrected data. We chose Sweden as a study domain to look at a Nordic region with a large number of water basins and an overall well-sampled region allowing to assess interesting network settings through sub-sampling.  

Sub-sampling and analysis for potential network settings is done for the seven hydrological clusters across Sweden as they are defined in Girons Lopez et al. (2021). Random sub-sampling (by 10%, 25%, 50%, 75%, and 90%) of each of the seven clusters shows a narrow range of (Shannon) entropy indicating excellent assignment of catchments to the seven clusters.  

Focusing on three clusters, which span Sweden’s North-South extend and mainly feature forested areas and a cluster covering mostly coastal lakes, we assess how much information remains in the data set if sub-sampled by hydro-geological parameters, such as baseflow and flashiness. Such tests allow us to determine ideal and minimum network settings with respect to observational and computational efforts based on different criteria relevant to scientific investigations and decision-making needs. 

 

Girons Lopez, M., Crochemore, L., and Pechlivanidis, I. G.: Benchmarking an operational hydrological model for providing seasonal forecasts in Sweden, Hydrol. Earth Syst. Sci., 25, 1189–1209, https://doi.org/10.5194/hess-25-1189-2021, 2021 
Filling a major gap in the LGM chronology of the Eastern Alps: New evidence from Enns and Mur glaciers (Austria)
Authors: Griesmeier Gerit E.U. , Braumann Sandra M. , Reitner Jürgen M. , Neuhuber Stephanie M. , Le Heron Daniel P. , Marchhart Oscar , Wieser Alexander
Published: February 2023

During the Last Glacial Maximum (LGM), large glacier tongues reached far into the alpine foreland and formed piedmont lobes. Common deposits are moraine “amphitheatres” directly connected to glaciofluvial deposits, which are both suitable for (direct) age dating. Over much of the Alpine realm, great efforts have been made to constrain the chronology of the LGM, yet in the eastern part, significant gaps exist, and absolute dates for glacial features are missing. Due to a gradual eastward change in terms of precipitation, moisture, and topography, glaciers did not advance as far in the eastern Alps and terminated in narrow inneralpine valleys. Evidence of their extent is therefore sparse and their deposits were mostly cannibalised by later erosional and depositional processes. Nevertheless, remnant terminal moraines from the Enns and Mur glaciers (mainly fed by the Niedere Tauern in the Central Alps) remain. These deposits contain blocks that can be dated with cosmogenic beryllium and aluminium surface exposure dating.For cosmogenic dating, two sites were investigated as follows. The Enns glacier developed north of the Niedere Tauern mountain range and one of its terminal tongues ended at Buchauer Saddle, where a terminal moraine complex is preserved. The moraine ridges reach a few tens of meters in height and contain mostly blocks of carbonate, with some quartz-containing blocks also present. All dated blocks are Palaeozoic quartz conglomerates/breccias, which crop out roughly 25 km upvalley.The ice masses of the Mur glacier accumulated south of the Niedere Tauern mountain range in the Mur valley. The glacier was divided into several tongues, one of them terminating near Pöls, where the most prominent moraine of the Mur glacier is preserved. It consists of a diamicton with a silty to clayey matrix and few components of pegmatite gneiss, amphibolite and other crystalline rocks. Datable blocks consist of coarse-grained pegmatite gneiss.Based on mapping relationships, the spatial context of the both moraine complexes suggest their deposition during the LGM. In this contribution, we will explore this hypothesis so far developed on the basis of field relations by presenting preliminary exposure ages of these landforms.
Climate Change Mitigation in The Bahamas - The Power of Earth Observation for Blue Carbon Accounting
Authors: Blume Alina , Traganos Dimosthenis , Pertiwi Avi Putri , Lee Chengfa Benjamin , Rio Marie-Helene
Published: February 2023

The seagrass ecosystem can sequester and store vast amounts of carbon in their soils and biomass, which renders them a strong natural climate solution for climate change mitigation. The carbon uptake capabilities of this coastal marine ecosystem have important implications for Multilateral Environmental Agreements like the National Determined Contributions of the Paris Agreement and the Sustainable Development Goals. However, the  value of seagrasses for these agendas is often overlooked due to a lack of spatially-explicit extent and carbon data. Modern Earth Observation advances can provide time- and cost-efficient solutions to minimise these data gaps.We utilised multi-temporal Sentinel-2 data within the cloud computing platform Google Earth Engine to quantify the current Bahamian seagrass extent, associated carbon stocks, and sequestration rates. Our approach combines big satellite data, pixel and object-based feature analysis, and scalable machine learning algorithms. We are envisaging to assess ecosystem extent changes using historic image archives (e.g. Landsat), and the integration of biophysical variables into our models (e.g. bathymetry, meadow patchiness).We estimate the current seagrass ecosystem extent to cover an area of up to 46,792 km2, storing 723 Mg carbon and sequestering about 68 times the amount of carbon dioxide that was emitted by The Bahamas in 2018.Our generated data highlights the importance of the seagrass ecosystem for climate change mitigation in The Bahamas and beyond, and showcases the necessity of including seagrass blue carbon in national climate agendas. This data and our developed earth observation approach can support policy makers and scientists from a national to a global climate action context.
Tracing the development of coastal ecosystems through satellite imagery: a case study from Ho Chi Minh City, Vietnam
Authors: Scheiber Leon , Schlurmann Torsten
Published: February 2023

Like many other coastal megacities, Ho Chi Minh City in Southern Vietnam is regularly affected by flooding from torrential rainfalls and storm surges. Global climate heating will exacerbate these natural hazards, but rapid urbanization has a share in the intensification of urban disaster risk as well. Proceeding surface sealing, uncontrolled land subsidence and the urban heat island effect are only a few of the factors increasing exposure to flooding, which often hits the most vulnerable parts of the population. To defend local residents and reduce flood-induced losses, classic protection measures like embankments, flood gates and large-scale pumping stations are implemented across Ho Chi Minh City. But as low-level inundations continue to cause frequent disruptions to the local economy, ecosystem-based solutions or so-called blue-green infrastructure are more and more seen as promising means to complement existing management strategies and ensure sustainable flood resilience.In our study, we investigate whether the role of coastal ecosystems in mitigating floods in Ho Chi Minh City is already reflected in recent urban developments. Specifically, we use multi-spectral Sentinel-2 imagery to calculate the Normalized Difference Vegetation Index (NDVI), a dimensionless indicator to describe terrestrial vegetation. The obtained annual NDVI maps have a spatial resolution of ca. 1 arc second and cover the years 2016 to 2022; special attention was given to the composition of cloud-free images. On this basis, temporal trends were determined that specify the (qualitative) development of bio-activity across the urban and suburban districts of the province. These local trends are complemented by annual histograms, which describe the relative frequency of specific NDVI ranges and thus allow estimations of ecosystem density. Unsurprisingly, preliminary results suggest constant ecosystem density for the Can Gio biosphere reserve in the South of the HCMC province, except for slight changes along its boundaries. For the urban districts of HCMC, however, ongoing urbanization can be traced by decreasing ecosystem density according to our assessment of NDVI values. The employed method provides promising results, yet currently still lacks a decent validation through ground truth data.
Relative Importance of Poroelastic Effects and Viscoelastic Relaxation for Co- and Postseismic Coulomb Stress Changes on Normal and Thrust faults: Insights from 3D Finite-Element Modeling
Authors: Peikert Jill , Hampel Andrea , Bagge Meike
Published: February 2023

Earthquakes on faults in the brittle upper crust cause sudden changes in pore fluid pressure as well as postseismic viscoelastic flow in the lower crust. Such transient processes change the velocity field in the crust and cause significant Coulomb stress changes on receiver faults in the vicinity of the source fault, which may trigger or delay next earthquakes. As previous studies focused on natural earthquakes and/or considered poroelastic and viscoelastic processes separately, the combined influence of poroelastic effects and viscoelastic relaxation on postseismic velocity and stress fields has not been systematically studied so far. In a previous study with 2D finite-element models, we showed that postseismic velocity fields contain signals from overlapping poroelastic and viscoelastic effects (Peikert et al., Tectonophysics, 2022). Here, we use 3D finite-element models with arrays of normal and thrust faults, respectively, to analyze the Coulomb stress changes resulting from the interaction between poroelastic effects and viscoelastic relaxation. In different experiments, we vary the permeability of the crust and the viscosity of the lower crust or lithospheric mantle, while keeping the other parameters constant. We also performed experiments with and without pore fluid flow and viscoelastic relaxation, to isolate the effects of fluid flow and viscoelastic relaxation from each other. Our results show that the coseismic (= static) Coulomb stress changes are immediately altered by the signal from poroelastic effects during the first month after the earthquake. In the first postseismic year, Coulomb stress changes arising from poroelastic effects are one order of magnitude stronger than Coulomb stress changes arising from viscoelastic relaxation. In models considering fluid flow, poroelastic effects dominate the stress field in the first two years. Viscoelastic relaxation already occurs in the early postseismic phase, but is overlapped by the strong signal from poroelastic effects and dominates the Coulomb stress change pattern from about the fifth postseismic year onward for several decades.  The Coulomb stress change patterns show a combined signal from poroelastic and viscoelastic effects already during the first postseismic year, if the viscosity is sufficiently low. For sufficiently low permeabilities, Coulomb stress changes induced by poroelastic effects overlap with the signals from viscoelastic relaxation and interseismic stress accumulation for decades. Finally, poroelastic and viscoelastic effects have a strong impact on the magnitudes and patterns of Coulomb stress changes and should therefore be considered together when analyzing Coulomb stress transfer between faults.
Inversion of the lateral density variations of the lithosphere using the full gravity gradient tensor
Authors: Root Bart
Published: February 2023

Flexural isostasy is commonly used to understand the relationship between the observed topography, the crustal structure, and the gravity. Compared to local isostasy, flexural models behave like low-pass filters on the crust-mantle interface. Using this methodology different internal structures are revealed showing the geometry of crustal and lithospheric structures. In the current flexure studies it is assumed that the lithosphere has uniform densities. The misfit between this method and the observed gravity data could be used to invert for lateral densities in the lithosphere.  In this study spectral analysis on the topographic and gravity results from the flexural models is performed to study the effect of lateral variations. For the inversion we use the full tensor of the gravity gradient as they show more sensitivity to the lithosphere structures. The inversion technique is based on spectral kernel models that are able to depict the sensitivity of satellite gravity data. Extensive synthetic analysis is been performed to acquire the best inversion settings and to study the uncertainty of the inversion results with respect to the chosen flexural model. A two-layer lateral density model (crust – upper mantle) is applied to the Sunda Subduction zone to yield more insights into the density structure of the subducting plate.
Spatio-temporal patterns in carbon distribution in supra-permafrost groundwater at a small-scale site in North-East Siberia
Authors: Raab Sandra , Castro-Morales Karel , Vonk Jorien , Hildebrandt Anke , Heimann Martin , Goeckede Mathias
Published: February 2023

Climate warming can influence a variety of landscape processes, including the transformation and transfer  of water, carbon and nutrients. In the Northern Hemisphere, permafrost underlays large parts of the land surface and represents a large reservoir of  organic carbon that is extremely vulnerable to changing climate conditions. Accelerated thaw can decompose permafrost carbon, and lead to modified exchange processes with the atmosphere (vertical pathway) and hydrosphere (lateral pathways). These carbon export rates are highly dependent on soil water conditions, suprapermafrost groundwater table location, and vegetation community. Depending on depth of thaw and dry or wet soil conditions, changes in the production and availability patterns of dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC), the three main carbon components in water, are expected. Shifts in lateral carbon export become more relevant for quantifying the total local carbon budget with predicted future permafrost degradation due to climate warming and resulting drier soil conditions. This study focuses on carbon distribution patterns of the three main carbon components (DOC, POC, DIC) within a floodplain tundra site near Chersky, Northeast Siberia. We compared a wet control site with a dry site affected by a drainage ring built in 2004. A network of piezometers was established to continuously monitor water table trends during the summer season (July to September) in 2017. On several key locations within that network, water was sampled to determine carbon concentrations (DOC, POC, DIC) and carbon isotopes (∆14C-DOC, δ13C-DOC, δ13C-DIC) in 2017. Here, we analyze and discuss the spatio-temporal carbon distribution on both sites with linkages to hydrological conditions (e.g. saturated zone) and carbon isotopic observations. The highest concentrations throughout both sites were found for DOC, followed by DIC and POC. DIC is relatively higher at wet sites compared to dry sites. Reversely, the organic carbon components, DOC and POC, were higher at dry sites. ∆14C-DOC can be associated with fresh material and decreased at all measurement sites with time of the season. Within that range, ∆14C-DOC decreased more at dry sites, when thaw depths were deepest within that site and where water tables were lower compared to wet sites, indicating the release of older carbon. Our results show that the distribution of carbon and the respective carbon isotopes are directly related to hydrological flow patterns. Understanding the carbon redistribution processes in these ecosystems is of relevance for assessing the carbon budget in disturbed permafrost areas. These findings will therefore be used to compare climate warming induced permafrost degradation at the dry (drained) site with the wet (control) site.
Interior heating of rocky exoplanets from stellar flares with application to Trappist-1 and Proxima Centauri
Authors: Grayver Alexander , Bower Dan , Saur Joachim , Dorn Caroline , Morris Brett
Published: February 2023

Many stars of different spectral types with planets in the habitable zone are known to emit flares. Until now, studies that investigated the long-term impact of stellar flares and associated Coronal Mass Ejections (CMEs) assumed that the planet's interior remains unaffected by interplanetary CMEs, only considering the effect of energetic particles interactions on the atmosphere of planets. Here, we show that the magnetic flux carried by flare-associated CMEs results in planetary interior heating by ohmic dissipation and leads to a family of new interior–exterior interactions. We construct a physical model to study this effect and apply it to the TRAPPIST-1 and Proxima Centauri stars whose flaring activity has been constrained by Kepler and TESS observations. We pose our model in a stochastic manner to account for uncertainty and variability in major input parameters. Our results suggest that the heat dissipated in the silicate mantle is both of sufficient magnitude and longevity to drive geological processes and hence facilitate volcanism and outgassing particularly for the innermost planets. Furthermore, our model predicts that Joule heating can further be enhanced for planets with an intrinsic magnetic field compared to those without. The associated volcanism and outgassing may continuously replenish the atmosphere and thereby mitigate the erosion of the atmosphere caused by the direct impact of flares and CMEs.