bluuebunny/crossref_metadata_2025 huggingface dataset:
Antarctic ice shelf front dynamics between 2015 and 2023
Authors: Baumhoer Celia A. , Dietz Andreas J. , Kuenzer Claudia
Published: February 2023

The Antarctic ice sheet is fringed by ice shelves regulating the ice flow into the ocean. The fronts of these ice shelves are constantly moving and are sensitive indicators of glaciological and environmental change. Previously, Antarctic ice shelf front change was not observed regularly due to limited availability of satellite imagery and time-consuming manual front delineations. The era of freely available SAR satellite data and recent developments in image processing with artificial intelligence created new opportunities for monitoring ice shelf front dynamics on a regular basis. Here, we present the IceLines dataset providing continuous time series of calving front dynamics for 36 major Antarctic ice shelves since 2015. The dataset consists of over 19,000 front positions extracted from Sentinel-1 satellite data by using a convolutional neural network called HED-Unet. The automatically extracted front positions can deviate from manual delineated fronts due to fast ice, mélange and icebergs close to the front by 209±12 m (5.2 pixel) on dual polarized imagery and 432±21 m (8.8 pixel) for single-polarized imagery whereas the frontal movement can be determined with higher accuracies of 63±68 m (1.6 pixel) for dual and 107±126 m (2.7 pixel) for single polarized imagery. To minimize errors and enhance quick usability, automatic separation of unreliable front positions (still accessible) is applied for an easy analysis of the dataset. This contribution features the analysis of the IceLines dataset providing new insights into Antarctic calving front dynamics by investigating intra-annual calving front dynamics, changing advance rates of ice shelf fronts, recent calving events and overall calving front change.
Using synthetic snow cover maps to determine the degree-day snowmelt factor of a distributed hydrological model
Authors: Wiersma Pau , Zakeri Fatemeh , Mariéthoz Grégoire
Published: February 2023

Snowmelt can vary largely across time and space, especially in complex terrain. However, hydrological models often represent snowmelt using a single static degree-day factor that relates the melt runoff with air temperature. Seasonally or spatially varying degree-day factors have been shown to better capture the snowmelt heterogeneity, but still rely on simplified parameterizations. One interesting solution proposed in the literature is to use MODIS satellite imagery to capture the true snowmelt heterogeneity, and use it to inform hydrological models on the temporal and spatial evolution of the degree-day factor on a near-daily basis. However, the limited spatial resolution of MODIS makes this process difficult to apply in complex mountainous terrain. Meanwhile, Landsat or Sentinel 2 satellite imagery could be an interesting alternative as they have a much higher spatial resolution but fall short in terms of temporal resolution. In this study, we overcome both these obstacles with a synthetically generated daily snow cover time series based on Landsat resampling. We use the daily synthetic snow cover maps to derive the snow cover depletion in each coarse resolution hydrological model grid cell, which in turn defines the degree-day factor for each cell using a transfer function. To capture the inherent uncertainty of this methodology, we run an ensemble of models using different meteorological forcings and different stochastic realizations of the synthetic snow cover maps. The resulting degree-day factors are evaluated through the skill of the modeled streamflow and snow water equivalent, using different transfer functions in several snow-influenced catchments in Switzerland. 
An Energy Transport View of ENSO Responses to Volcanic Forcing
Authors: Fang Shih-Wei , Timmreck Claudia
Published: February 2023

El Niño-Southern Oscillation (ENSO) is one of the major climate phenomena impacting the globe. When a volcanic eruption happens, how ENSO will respond has still no consensus in proxy data though climate models tend to have an El Niño tendency. In this study, using 100 members of diverse (in locations and magnitude) idealized volcanic forcing ensembles, we found that the ENSO responses to north and south extra-tropical eruptions are related to the energy transport to the cooling hemisphere and involve direct and indirect responses through atmospheric and oceanic transport. The north extratropical forcing leads to more El Niño up to three years after eruptions, which is related to the direct atmospheric responses of the southward movement of ITCZ for transporting more energy to the north. The indirect oceanic transport then takes over afterward, leading to more La Niña due to more upwelling in the equatorial eastern Pacific. The south extra-tropical eruptions have less El Niño tendency due to the northward replacement of ITCZ. As the indirect oceanic transport also results in equatorial mean state changes, which may lead to distinct ENSO responses. The long-term ENSO responses from extra-tropical cooling will also be investigated through the simulations from the Extratropical-Tropical Interaction Model Intercomparison Project (ETIN-MIP) experiment.
A Rugged, Portable and Intelligent Analogue Seismometer for Future and Pre-Existing Arrays – Güralp Certis
Authors: Whealing Dan , Lindsey James , Watkiss Neil , Reis Will
Published: February 2023

Seismic networks often face logistical and financial challenges that require portability, longevity and interoperability with existing equipment.Güralp have combined proven ocean bottom, borehole and digitiser technology to produce an analogue seismometer with intelligence that benefits networks of all sizes. The Güralp Certis is a broadband analogue instrument that incorporates specific aspects of its sister digital instrument (Certimus) while still remaining compatible with third-party digitisers.Each Certis stores its own serial number, calibration and response parameters internally and will automatically communicate these to a connected Minimus digitiser. This allows seismometer-digitiser pairings to be changed without manual entry of new parameters. If using GDI-link streaming protocol with the Minimus, these metadata parameters are transmitted within (and therefore inseparable from) the datastream itself. Therefore, this small piece of intelligence in the analogue sensor removes the need for any manual re-entry of response parameters anywhere along the sensor-digitiser-client chain.Certis enables users to install in locations with poor horizontal stability (e.g., glaciers, dynamic landslide scarps, water-saturated soils), without the need for cement bases or precise levelling, as the sensor can be deployed at any angle regardless of which model digitiser is connected. Due to its small size, low weight and ultra-low power consumption, Certis significantly reduces logistical efforts and makes short term temporary deployments far easier.Certis addresses many challenges of traditional seismometer deployments, including cost, but provides a flexible and simple solution for seismic monitoring applications across all disciplines.
Time-Domain Source Parameter Estimation of natural and man-induced micro earthquakes at The Geysers geothermal field
Authors: Longobardi Valeria , Nazeri Sahar , Colombelli Simona , Rea Raffaele , De Landro Grazia , Zollo Aldo
Published: February 2023

Water injection in geothermal areas is the preferential strategy to sustain the natural production of geothermal resources. In this context, monitoring microearthquakes is a fundamental tool to track changes in the reservoirs in terms of soil composition, response to injections, and resource exploitation in space and time. Therefore, the refined source characterization is crucial to better estimate the size, source mechanism, and rupture process of microearthquakes, as possibly related to industrial activities and to identify any potential variation of the background seismicity. Standard approaches for source parameters estimation are ordinarily based on the modelling of Fourier displacement spectra and its characteristic parameters, the low-frequency spectral level and corner frequency. Here we apply a time-domain innovative technique that uses the curves of P-wave amplitude vs time along the seismogram. The methodology allows estimating seismic moment, source radius, and static stress drop from the plateau level and the corner-time and of the average logarithm of P-wave displacement versus time with the assumption of a triangular moment rate function, uniform rupture speed, and constant/frequency-independent Q-factor. In the current paper, this time-domain methodology is implemented to a selected catalog of micro-earthquakes consists of 83 events with moment magnitude ranging between 1.0 and 1.5, occurred during 7 years (2007-2014) of fluid extraction/injection around Prati-9 and Prati-29 wells at The Geysers Geothermal field.
Accurate Interpretation of Urban Mangrove Stand Structure Based on Low-altitude Unmanned Aerial Vehicle System
Authors: Shen Xiaoxue , Zhai Chaoyang , Yang Fang , Li Ruili
Published: February 2023

The effective management of the mangrove forests is especially important, which requires precise and timely monitor of the stand structure of mangrove forest. Meanwhile, stand structure is a key feature that indicates the health status of mangrove forests. Therefore, we developed an effective method to interpret the stand structure of urban mangrove forests using visible light remote sensing images from Unmanned Aerial Vehicles (UAV). The results showed that: (1) Pixel-based deep natural networks under the constraint of physical parameters (tree height) have been explored for mangrove species classification, and the overall classification accuracy of the whole study site was 88.29%. (2) Based on watershed algorithm and the relationship between tree height and tree crown, single tree crown segmentation in non-closed mangrove area was realized, with recognition accuracy of 78.57%~ 88.89%. (3) Based on the obtained stand structure parameters, including the size ratio, angle scale, mixing degree, etc., a stand structure health evaluation model was established to determine the health level of a mangrove forest. Stand structure evaluation score (A) in Futian Mangrove National Nature Reserve was derived that the core area (A: 0.9315~0.9391) was better than the non-core area (A: 0.8622~0.9127). The proposed method will reduce the time and effort required for future mangrove plant observations and contribute to future assessments of the health of mangrove forests.
From Correlation to Causation: Discovering the Drivers of Urban Water Demands in the Contiguous United States
Authors: Hao Wenjin , Cominola Andrea , Castelletti Andrea
Published: February 2023

Urban water demands vary across spatio-temporal scales, driven by multiple socio-demographic, climatic, and urban form factors. Identifying influential drivers, along with their individual and compound effects on urban water consumption, is essential to forecasting future water demand, addressing urban water security, and informing water governance. Model-free and model-based Input Variable Selection (IVS) has been extensively applied to investigate important predictors of urban water demands. However, most IVS methods identify correlations and mutual information between variables, which do not imply causation. More recently, causal discovery has developed as an active area of research in many research fields, including, e.g., neuroscience, finance, and climate science. Causal discovery improves IVS by identifying causally meaningful relationships between variables, distinguishing indirect from direct dependencies, and recognising relevant drivers among multiple variables.In this work, we investigate predictive and causal factors of urban water use across the Contiguous United States (CONUS). We rely on open data of monthly municipal water consumption from 126 cities in the US for the period 2010-2017 and data on candidate socio-demographic, climatic, and built environment predictors from multiple sources, including the U.S. Census Bureau, the American Community Survey, and the PRISM climate data set. We first test the state-of-the-art W-QEISS wrapper method to identify equally-informative subsets of predictive factors for urban water demands. These subsets are the solutions of a four-objectives optimisation problem that maximises the predictive accuracy of a data-driven model and feature relevance while minimising the number of selected predictors and their redundancy. Results show that historical water consumption is the most relevant factor to predict future demands, followed by some socio-demographics, climatic factors, and building characteristics, including the median number of rooms in housing units, unemployment rate, Palmer Drought Severity Index (PDSI), and building construction years. Preliminary results for individual climate regions also highlight local effects, with PDSI becoming more relevant for arid regions than the continental-scale results. Second, we extend our analysis to causal discovery by applying a neural Granger model to interpret non-linear Granger causality and temporal structures within time series. Granger causality describes whether past values of a time series xt could predict future values of another series yt, assuming causal effects are ordered in time (i.e., cause before effect). This allows for finding the specific causes of urban water demands in our case (in a Granger’s sense). We finally compare the causality results with the results of IVS to illustrate the different interpretations of urban water demand drivers.  
Flow intermittence prediction using a hybrid hydrological modelling approach: a guide to reducing uncertainty related to observed intermittence data
Authors: Mimeau Louise , Künne Annika , Branger Flora , Kralisch Sven , Devers Alexandre , Vidal Jean-Philippe
Published: February 2023

Rivers are rich in biodiversity and act as ecological corridors for plant and animal species. With climate change and increasing anthropogenic water demand, more frequent and prolonged periods of drying in river systems are expected, endangering biodiversity and river ecosystems. However, understanding and predicting the hydrological mechanisms that control periodic drying and rewetting in rivers is challenging due to a lack of studies and hydrological observations, particularly in non-perennial rivers.Within the framework of the Horizon 2020 DRYvER (Drying River Networks and Climate Change) project, a hydrological modelling study of flow intermittence in rivers is being carried out in 6 European catchments (Croatia, Spain, Finland, France, Hungary, Czech Republic) characterized by different climate, geology and anthropogenic use. The objective of this study is to represent the spatio-temporal dynamics of flow intermittence at the reach level in meso-scaled river networks (between 200 km² and 350 km²). The daily and spatially distributed flow condition (flowing or dry) is predicted using the J2000 distributed hydrological model coupled with a Random Forest classification model. Observed flow condition data from different sources (water level measurements, photo traps, water temperature measurements, citizen science applications) are used to build the predictive model. In this study we aim to evaluate the impact of the observed flow condition dataset (sample size, spatial and temporal representativeness) on the performance of the predictive model.Results show that the hybrid modelling approach developed in this study allows to predict precisely the spatio-temporal patterns of drying in the 6 catchments. This study shows the value of combining different sources of observed flow condition data to reduce the uncertainty in predicting flow intermittence.
Fast coastal tsunami amplitude forecasting along the French Mediterranean shoreline based on a transfer function method
Authors: Gailler Audrey , Hébert Hélène
Published: February 2023

In the framework of operational conditions, the real time coastal modeling in near field is challenging to obtain accurate and reliable tsunami warning products for flooding hazard. Maps of inundation and impacts for planning community response can be produced through coastal predictions with run-up computation by solving numerically high-resolution forecast models in real time, taking into account all local effects. However, these runs are too time consuming in near field and operational context. An alternative approach is based on early prediction tools of the coastal wave amplitude calculated from empirical laws or transfer functions derived from these laws. Such tools are suitable in near field context (almost ten times faster than the high-resolution runs), but all local effects are not well taken into account and the assessment of run-up is missing. The linear approximations of coastal tsunami heights are provided very quickly using the maximum wave heights from a computationally cheap regional forecast, with global and conservative estimates.Within the French Tsunami Warning Center (CENALT), a forecasting tool based on a transfer function method is being implemented. This fast prediction technique is based upon a recently extended version of the usual Green's Law (Giles et al., 2022[1]), which introduces local amplification parameters with the aim of capturing the neglected localized effects. The method includes an automated approach which optimizes for these local amplification parameters by minimizing a cost function.Local amplification parameters are calculated for the entire French Mediterranean coastline at 25 m resolution from a data set of 12 scenarios (high-resolution simulations). The forecasting results capabilities are analyzed, and shown for several coastal sites. The local tsunami wave heights modeled from the transfer function present a good agreement with the time-consuming high resolution models. The linear approximation is obtained within 1 min and provides globally estimates within a factor of two in amplitude. Although the resonance effects in harbors and bays are not reproduced and the horizontal inundation calculation needs to be studied further, this tool is well suited for an early first estimate of the coastal tsunami threat forecast.
[1] Giles, D., Gailler, A., & Dias, F. (2022). Automated Approaches for Capturing Localized Tsunami Response—Application to the French Coastlines. Journal of Geophysical Research: Oceans, 127(6), e2022JC018467.
Key risks and illustrative adaptation pathways for Europe
Authors: Muccione Veruska , Haasnoot Marjolijn , Alexander Peter , Bednar-Friedl Birgit , Biesboek Robbert , Georgopoulou Elena , Le Cozannet Gonéri , Schmidt Daniela
Published: February 2023

The key risks assessment developed in the context of the IPCC Working Group II AR6 Europe chapter pulled together multiple line of evidence across the published literature and used expert elicitation to identify those risks with the greatest potential to become severe or that are already severe now. Four key risks have been identified for Europe, namely: 1) heat stress to human and ecosystems; 2) loss of agriculture productivity due to heat and dry conditions and extreme weather; 3) water scarcity to multiple interconnected sectors; 4) coastal and inland flooding. Alongside the assessment of the key risks, an assessment of the effectiveness of discrete adaptation options was also performed following a protocol which defines adaptation effectiveness as the risk reduction potential of an adaptation option from a given baseline. More than 50 discrete options were assessed with the greatest majority showing medium effectiveness to reduce risks. These two assessments have brought forward some critical aspects in adaptation decision making which have inspired further analysis. These aspects are 1) the need for long term planning, 2) the diversity of contexts within which adaptation takes place, 3) the existence of multiple interacting risks and 4) the limited knowledge on the effectiveness of adaptation as opposed to the knowledge on adaptation limits. 

We explore here the use of warming sensitive adaptation pathways as a framework to address these critical aspects and present reflections on how illustrative adaptation pathways can support effective decision making that also reduces the implementation gap. For example, our pathways framework points at a dichotomous future to reduce coastal flooding in the long term and a future where all options will be needed to reduce the risks of water scarcity. The framework also shows that considering multiple risks together under different levels of warming can inform adaptation decision making about potential constraints, trade-offs, and lock-ins. In general, for the illustrative adaptation pathways to be useful planning tools certain preconditions must be in place such as legitimacy through monitoring and evaluation as well as human and financial capital towards multiple and diverse pathways.
A Preliminary Forecast Study of the North Indian Ocean Tropical Cyclones Using a Coupled Atmosphere-Ocean Model
Authors: Farhangmehr Aref , Ghader Sarmad , Ali Akbar Bidokhti Abbas Ali , Ranji Zahra
Published: February 2023

Tropical cyclones (TCs) are severe weather marvels, occur in warm tropical waters. These phenomena are among the most influential atmospheric-oceanic events in subtropics regions as the northern part of the Indian Ocean, affecting the Arabian Sea and the Oman Sea, which often cause severe damage to the coastal areas. The interaction between the atmosphere and the upper ocean plays an important role in the structure of TCs, in which successful connections between ocean circulations and the intensity and track of TCs have been identified. TCs derive their energy primarily from the release of latent heat through evaporation and sea spraying in the atmosphere boundary layer. This implies that the presence of a moisture source, with sufficiently warm sea surface temperature (frequently above 26°C) is required to sustain the flux of moisture from the ocean to the atmosphere. The most visible effect of TC passage is the cooling of the sea surface temperature (SST) as the response of the ocean mixed layer (OML) temperature. This decrease in SST has a negative feedback on the intensity of TCs, as it suppresses the heat exchange flux between the atmosphere and the ocean, consequently it can affect the TC track.To investigate the effect of the temperature field on TCs structure, TC Shaheen (2021) with unusual track and entry into the Gulf of Oman is studied. In this regard, Weather Research and Forecasting (WRF) model was used with two different configurations. First, WRF was ran standalone and SST field was only adopted from global models as initial conditions and were not updated during the simulation. Then, as the second configuration, WRF model was coupled with an ocean finite volume model and the SST field was updated online during the simulation. The initial conditions of the ocean temperature, salinity and velocity field were taken from GOFS 3.1 global reanalysis product from the HYCOM Consortium. Primary result for the selected event implies that SST correction during TC simulation with WRF improves air-sea heat flux and has a pronounced effect on the TCs’ intensity and track predictions. Cold wake underside of the TC led to a remarkable heat flux loss from ocean surface into the storm. Hence, the TC size is reduced and the maximum wind speed of the storm is intensified.
40Ar/39Ar dating of pseudotachylytes: a case study on post-metamorphic brittle fault in the NW Alps
Authors: Lugoboni Zeno G. , Arienti Gloria , Barberini Valentina , Bistacchi Andrea , Cannella Christian , Caprarulo Simona , Villa Igor M.
Published: February 2023

Pseudotachylytes are solidified frictional melts produced by seismic fault slip. Being melts that solidified in seconds or minutes after the seismic slip event, they have always been considered a very favourable tool to date brittle deformation. However, since all pseudotachylytes are composed of inherited clasts, melt-derived matrix and (quite often) also alteration products, it is necessary to discriminate the Ar contribution of these three reservoirs to obtain meaningful ages. This can be done by analyzing Ca/K and Cl/K signatures provided by Ar systematics. Furthermore, microstructural analysis and microCT allow quantifying the clast-to-pseudotachylyte matrix ratios for each sample, and XRPD allows detecting potential alteration phases. Here we present the results of step-heating 40Ar/39Ar analyses performed on pseudotachylytes of the Trois Villes Fault and the Quart Fault, which crop out in a region of the Western Alps (Aosta Valley) affected by three different post-metamorphic brittle deformation phases: D1 characterized by NW-SW extension, D2 with NE-SW extension, and D3 showing N-S extension. The relative chronology of these deformation phases is based on consistent cross-cutting relationships. D1 ages of 29–32 Ma have been inferred from syn-kinematic magmatic dikes and hydrothermal veins. However, no absolute ages were so far available for D2 and D3, as direct radiometric dating of fault rocks has never been performed before in the area. Our results are consistent with the relative chronology and greatly improve our understanding of the tectonics of this area.
The evolution and dynamics of the sulfate aerosol plume in the stratosphere after the exceptional Tonga eruption of 15 January 2022
Authors: Duchamp Clair , Legras Bernard , Sellitto Pasquale , Podglajen Aurélien , Carboni Elisa , Siddans Richard , Grooss Jens-Uwe , Ploeger Felix , Khaykin Sergey
Published: February 2023

We use a combination of seven space-borne instruments to study the unprecedented stratospheric plume after the Tonga eruption of 15 January 2022.The aerosol plume was initially formed of two clouds at 30 and 28 km mostly composed of submicron-sized sulfate particles, without ashes washed-out within the first day following the eruption. The large amount of injected water vapour led to a fast conversion of SO2 to sulfate aerosols and induced a descent of the plume to 24-26 km over the first 3 weeks by radiative cooling. Whereas SO2 has returned to background levels by the end of January, volcanic sulfates and water still persisted after 6 months, mainly confined between 35°S and 20°N until June due to the zonal symmetry of the summer stratospheric circulation at 22-26 km. Sulfate particles, undergoing hygroscopic growth and coagulation, sediment and gradually separate from the moisture anomaly entrained in the ascending branch Brewer-Dobson circulation. Sulfate aerosol optical depths derived from the IASI infrared sounder show that during the first two months the aerosol plume was not simply diluted and dispersed passively but rather organized in concentrated patches. Space-borne lidar winds suggest that those structures, generated by shear-induced instabilities, were associated with vorticity anomalies that may have enhanced the duration and impact of the plume.Reference: ACP Highlight, DOI: 10.5194/acp-22-14957-2022
Geological evolutionary model of the Costa Rica subduction margin
Authors: Parente Fabrizio , Sulli Attilio
Published: February 2023

The Middle American Trench (MAT) is one of the most complex subduction margins all over the earth surface. Its geodynamical complexity is due to the interaction between five major lithospheric plates: North America, Caribbean, Cocos, Nazca and South America; between them is the Panama microplate. We focused on the Costa Rica subduction margin, which is a portion of the MAT and it is characterized by some peculiarities with respect to the other portions of the MAT. Along the Costa Rica offshore the subduction of the Cocos Plate is currently developing towards NE, beneath both the Caribbean Plate and the Panama Microplate, with a rate that increases from NW (87 mm/yr), in correspondence of the Nicoya Peninsula, to SE (92-95 mm/yr), in correspondence of the Osa Peninsula.    The Cocos Plate formed, together with the Nazca Plate, about 28 Ma from the Farallon Plate fragmentation in turn due to the formation of the East Pacific Rise (EPR). The subduction process is extremely seismogenetic and caused some earthquakes up to 7.8 Mw (1950): one of the most recent hits Nicoya on September 5th, 2012 (Mw 7.6). The migration of the Cocos Plate towards the Galapagos plume generated, about 14 Ma, the Cocos Ridge, a strip of oceanic ridge that is currently subducting beneath the southeastern margin of Costa Rica, in correspondence of the Osa Peninsula. The beginning of subduction, dated between 8 and 1 Ma, generated an isostatic rebound that gave rise to a general uplift generating the Cordillera de Talamanca, which emerged between 4.5 and 3 Ma and representing the extinct portion of the volcanic arc.     The main aim of this study is to provide a reliable model about the evolution of the Costa Rica subduction margin, paying attention on the Cocos Ridge subduction and to understand how this affects the evolution of the margin. Through the seismostratigraphic interpretation of several multichannel seismic reflection profiles, together with morphobathymetric data, well data from ODP Leg 170, focal mechanisms and oceanic crust age variation chart along the MAT, as well as the Costa Rica geological map, produced by USGS, we recognized some evidence and mechanisms responsible for the uplift that affected the area (e.g. underthrusting process and strike-slip faults) and how this could be related to the subduction of the Cocos Ridge and of several seamounts recognized along the Costa Rica subduction margin. The Cocos Ridge subduction is also responsible for the magmatism recognized along the Nicoya Peninsula offshore, as well as of the variation of the slab geometry recognized through the realization of a 3D model of the Wadati-Benioff Plane.
Convolutional neural network for normal fault scarp characterization : application to the Trans-Mexican Volcanic Belt
Authors: Pousse-Beltran Léa , Giffard-Roisin Sophie , Audin Laurence , Lacan Pierre , Lallemand Theo , Núñez Meneses Andres
Published: February 2023

Normal fault markers in the landscape such as scarp are records of fault activity. The scarp morphology is used for exemple to estimate slip rates or rupture behaviors. The scarp morphology varies along strike, and needs to be estimated to assess this variation. Currently this is often a time-consuming step with expert-dependent results, often qualitative and with uncertainties that are difficult to estimate. To overcome those issues, we are developing a bayesian supervised machine learning method using convolutional neural networks (CNN) trained on a database of simulated profiles, called ScarpLearn. We train the CNN to use high resolution data (< 5m). From a 2D topographic profile across normal fault scarps, ScarpLearn is able to automatically give the scarp height with an uncertainty and to illuminate the area of the profile containing the scarp. We apply ScarpLearn for the characterization of normal active faults in the Trans-Mexican Volcanic Belt. This region is a slow deforming area (~0.2±0.05 mm/yr), which extends over more than 800km, crossed  by more than 600 potentially active faults but less than 5% of those have been correctly characterized by paleoseismological studies. In this context an automatic method to characterize the escarpments in a global, reproductible, robust (not expert-dependent) quantitative way will be highly valuable and a great step towards a better characterization of the seismic hazard of the region. In particular we tested our approach across the Ameca-Ahuisculco fault system, and by comparing ScarpLearn with with other methods based on profile analisis (not based on deep learning), we explore the advantages (computation time, accuracy, uncertainties) that deep learning methods bring, as well as the current limits (such as bias and dependance of the resolution).
Changes in global fire regimes under idealized overshoot scenarios
Authors: Nieradzik Lars , Lee Hanna , Miller Paul , Schwinger Jörg , Wårlind David
Published: February 2023

Within the framework of the project IMPOSE (Emit now, mitigate later? IMPlications of temperature OverShoots for the Earth system) six idealized emission-overshoot simulations have been performed with the Earth System Model NorESM2-LM2 and used as forcing for the 2nd generation dynamic global vegetation model LPJ-GUESS with its fire-model SIMFIRE-BLAZE to investigate the impact of different CO2 overshoots on global wildfire regimes.The simulations describe a set of scenarios with high, medium, and low accumulative CO2 emissions and each of which has a short (immediate) and a long (100 years) peak of accumulative CO2 emissions before declining towards a baseline simulation of 1500 PgC accumulatively emitted within the first 100 years.The results show that the height of the overshoot has an impact on global fire regimes while its duration does not seem to play a significant role 200 years after peak CO2. Overall, we can see that changes in vegetation composition following the temperature anomaly are the main driver for changes in global wildfire frequency. While in the low overshoot scenarios burnt area has almost converged towards the baseline simulation, the extremest scenarios show the lowest burnt area at the end of the simulation period, indicating that vegetation changes, especially in low latitudes, have been most significant and/or are still ongoing.
Cohesive sediments drive the transition between river- and tide-dominated estuaries through floodplain infilling
Authors: Baar Anne , Brückner Muriel
Published: February 2023

Estuaries are dynamic landscapes where river and tidal currents interact and form complex channel-bar patterns and intertidal floodplains. Mud has cohesive forces and settles mainly in calm or protected areas, such as on top of intertidal flats and along estuary fringes. In general, an increase in river discharge dampens the tidal currents and increases the supply of sand and mud from the hinterland, which results in a transition from tide-dominated estuaries to aggrading river-dominated estuaries. However, it is unknown how increasing river discharge, relative to the tidal prism, and a resulting increase in mud supply controls bar patterns, sediment transport rates and estuary width and length. Our objective is to systematically quantify these characteristics and the large-scale estuary equilibrium as a function of river discharge, tidal prism and mud concentration using a large-scale and long-term Delft3D-2DH idealized estuary model with freely migrating bars and channels. Results show that mud reduces the intertidal area and significantly changes bar dimensions by infilling, stabilizing floodplains and preventing bar splitting. Infilling of the intertidal area focuses the flow in the channels, resulting in two contrasting trends: 1) the tidal currents are amplified by channel deepening or 2) tidal currents are dampened by the river discharge when channel deepening is prevented, which results in a quicker transition from tide-dominated to river-dominated estuaries. This difference in response depends on mud supply, estuary size and river discharge relative to tidal prism. Furthermore, sediment transport in the intertidal area becomes more ebb-dominant due to the reduced water depths and flood flow velocities, resulting in increasing sediment export and stronger ebb-dominance compared to sandy estuaries. 
Phosphorus Transport in Nano Rockphosphate Treated Soils
Authors: Perli Monisha , Mailapalli Damodhara Rao
Published: February 2023

The excessive usage the phosphorous (P) fertilizers in agricultural soils is associated with several problems such as accumulation of phosphorous in the soil, heavy metal pollution, and eutrophication of surface water resources. The nano rock phosphate (nano RP) was found to be an efficient phosphorous fertilizer agronomically, but the transport behaviour of nano rockphosphate is still unknown. Therefore, an attempt was made in this study to investigate the transport behaviour of nano RP by conducting a short-term soil column experiment. The treatments were considered as control, Single Super Phosphate (SSP), bulk RP and nano RP at standard recommendations; each treatment was replicated three times. Leachate samples were collected after every water application. After 15th day, the soil samples were extracted from the columns from three depths, 0-1cm, 9-10cm and 34-35cm. Leachate samples and soil samples were analyzed for Ortho-P and Total P. The mobility of Ortho-P is greater in nano RP treated soils compared to that of SSP and bulk RP treated columns. It may be due to its lowered particle size which has increased the solubility of P. The SSP treated columns have higher amounts of unevenly distributed total – P compared to that of nano and bulk RP treated columns, proving the reduction in P accumulation in nano RP treated soil. The nano sized phosphorous particles can increase the mobility of P and thereby reduce the accumulation of phosphorous in soils. Hence, the application nano RP may be the best alternative to SSP, to maintain a healthy soil environment. Long-term and field scale studies are suggestable to confirm the same transport behaviour of nano phosphorous in real field conditions. Keywords: Nano-rockphosphate, phosphorus transport, soil pollution.
Diagnosing the AMOC slowdown in a coupled model: a cautionary tale
Authors: Gérard Justin , Crucifix Michel
Published: February 2023

It is now established that the increase in atmospheric CO2 is likely to cause a weakening, or perhaps a collapse of the Atlantic Meridional Overturning Circulation (AMOC). To investigate the mechanisms of this response in CMIP5 models, Levang and Schmitt (2020) have estimated offline the geostrophic streamfunction in these models, and decomposed the simulated changes into a contribution caused by the variations in temperature and salinity. They concluded that under a warming scenario, and for most models, the weakening of the AMOC is fundamentally driven by temperature anomalies while freshwater flux changes actually act to stabilize it.However, given that both ocean temperature and salinity are expected to respond to a forcing at the ocean surface, it is unclear to what extent the diagnostic is informative about the nature of the forcing. To clarify this question, we used the Earth system Model of Intermediate Complexity (EMIC) cGENIE, which is equipped with the C-GOLDSTEIN friction-geostrophic model (Marsh et al. (2011)). First, we reproduced the experiments simulating the RCP8.5 warming scenario and observed that cGENIE behaves similarly to the majority of the CMIP5 models considered by Levang and Schmitt (2020), with the response dominated by the changes in the thermal structure of the ocean.Next, we considered hysteresis experiments associated with (1) water hosing and (2) CO2 increase and decrease. In all experiments, changes in the ocean streamfunction appear to be primarily caused by the changes in the temperature distribution, with variations in the 3-D distribution of salinity compensating only partly for the temperature contribution. These experiments reveal also limited sensitivity to changes in the ocean's salinity inventory. That the diagnostics behave similarly in CO2 and freshwater forcing scenarios suggests that the output of the diagnostic proposed in Levang and Schmitt (2020) is mainly determined by the internal structure of the ocean circulation, rather than the forcing applied to it.Our results illustrate the difficulty of inferring any information about the applied forcing from the thermal wind diagnostic and raise questions about the feasibility of designing a diagnostic or experiment that could identify which aspect of the forcing (thermal or haline) is driving the weakening of the AMOC.AcknowledgementsThis is a contribution to the WarmAnoxia project funded by the Belgian National Fund of Scientific Research.References:Levang, S. J. and Schmitt, R. W. (2020). What causes the amoc to weaken in cmip5? Journal of Climate, 33(4):1535–1545.Marsh, R., Müller, S., Yool, A., and Edwards, N. (2011). Incorporation of the c-goldstein efficient climate model into the genie framework:" eb_go_gs" configurations of genie. Geoscientific Model Development, 4(4):957–992.
Monitoring active tectonics via fault micro-displacements in western Slovenia
Authors: Novak Uroš
Published: February 2023

Western Slovenia belongs to actively deforming north-eastern Adriatic region. Active tectonic deformations of the region are a response to the anti-clockwise rotation of Adria and still ongoing collision with Eurasia. Active deformations are generally accommodated by right-lateral strike-slip and thrust faulting at rates of 2–4 mm/yr.Monitoring of active tectonics at the junction of seismically active NW External Dinarides and Southern Alps (Slovenia) through quantification of micro-displacements of faults began in 2004, with a TM 71 extensometer situated in Postojna cave (NW External Dinarides). At present there are 12 monitoring sites with TM 71 and 72 extensometers throughout Slovenia, 9 of the instruments are stationed in natural and artificial cave environments. Cave climates are considered to be stable and thus provide a reliable environment for micro-displacement monitoring, minimizing or nullifying the effect of fluctuating temperatures on the TM instrument. The instruments were preferably installed in major regional Dinaric fault zones (NW-SE direction). Where the latter wasn’t possible, suitable locations on their ancillary faults was chosen as an indirect substitute. All the monitored TM extensometer sites display tectonic displacements, that on average range from a few microns to several tens of microns in time scales from days to years. Postojna cave is one of the most intriguing micro-displacement monitoring sites. The site exhibited large tectonic transient signals that coincided with the local swarm-like earthquake activity in the years, 2009-2010 and 2014-2015. Monitoring site of Pološka cave in Julian Alps (Southern Alps) in addition to recording tectonic displacements, inadvertently records some displacements that are not tectonic in origin, but rather exhibits slope instability, likely deep-seated gravitational slope deformation. TM extensometer micro-displacement monitoring in Slovenia is still an ongoing project.Of late, creepmeters were installed on major active western Dinaric regional faults, in 2022. In an effort to advance the understanding of characteristics and relationships between earthquake activity and potential fault creep. A fault creep monitoring campaign, with some instruments already installed, on two major active western Dinaric faults, Idrija and Raša fault, has begun and more are pending to be installed on the Dinaric fault system.
Investigating the Impact of Wildfires on Surface Albedo in Africa Using MODIS Data
Authors: Flegrova Michaela , Brindley Helen
Published: February 2023

Wildfires can have significant impacts on the Earth's surface albedo, with effects that can be long-lasting. In Africa, the frequency and severity of wildfires are changing due to a combination of factors including drought, land use change, and human activity. However, the impact of wildfires on surface albedo in Africa is not well understood and previous research has produced conflicting results.In this study, we are using Moderate Resolution Imaging Spectroradiometer (MODIS) data to investigate the potential changes in surface albedo following wildfires in Africa. Our preliminary results suggest that wildfires may have a complex and variable impact on albedo, with some regions potentially experiencing a decrease in albedo and others an increase or no significant change following a wildfire.We are also exploring the use of different approaches to analyse the MODIS data to better understand how the choice of method may impact the results and looking how the effect varies for different land cover types. In addition, we are using Fire Radiative Power data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) to examine the role of fire intensity in driving albedo changes.This research aims to provide new insights into the impact of wildfires on surface albedo in Africa, the underlying mechanisms driving these changes and how different analysis methods affect the conclusions. These results may have important implications for land management strategies in the region, and for understanding the impact of wildfires on local climate and ecosystem processes.
The paradox of the darkening planet and the Earth’s climate sensitivity
Authors: Cox Peter , Williamson Mark , Clarke Joe , Huntingford Chris , Ritchie Paul
Published: February 2023

Studies of the observed record of global warming suggest that the Earth’s climate sensitivity is at the lower end of the range produced by the CMIP6 Earth System Models (Jimenez and Mauritsen, 2019; Nijsse et al., 2020; Tokarska et al., 2020). However, studies based on top-of-the-atmosphere fluxes often suggest the opposite (Brown et al., 2017; Sherwood et al., 2020).Earthshine estimates (Goode et al., 2021) and satellite measurements of the planetary albedo from CERES (Loeb et al., 2018) both indicate that the Earth has darkened significantly over the past two decades. Planetary darkening is also simulated in CMIP6 historical simulations , but the models with the highest climate sensitivities tend to fit the observed decline in planetary albedo much better. Observed planetary darkening therefore favours higher climate sensitivities, but constraints based on ground-based global warming records favour lower climate senstivities.We explore this apparent paradox by calculating the contributions to changes in global warming that arise from diagnosable changes in planetary albedo and effective global emissivity, in both models and observational records. Differences between low and high sensitivity models are found to be predominantly due to the rate at which the modelled planetary albedo declines, which can in principle be due to a combination of forcing and feedbacks. However, planetary darkening in higher sensitivity models is primarily due to reductions in cloud cover, which results in a positive SW cloud feedback.By contrast, the planetary darkening seen in the CERES satellite record is driven not by reductions in cloud cover, but instead by the darkening of clouds, and to a lesser extent by the darkening of clear skies. This suggest that darkening in CERES is driven by reductions in aerosols, which leads to reductions in negative aerosol forcing.  Planetary darkening in CERES therefore seems to be due primarily to changes in aerosol forcing.Our proposed resolution to ‘The paradox of the darkening planet and the Earth’s climate sensitivity’ is therefore that climate sensitivity is indeed towards the lower end of the CMIP6 model range (as suggested by observed records of global warming), and that higher sensitivity models get the rate of planetary darkening ‘right’ but by the wrong mechanism (i.e. as a cloud forcing rather than as an aerosol feedback).  We will back this up by comparing the spatial patterns of planetary albedo change from models and the CERES satellite data, and finish by discussing possible implications for the time-varying aerosol precursor fields that are used to drive the CMIP6 simulations.