bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing the performance of EQTransformer by parameter tuning and comparison to handpicked benchmark datasets in a subduction setting
Authors: Najafipour Nooshin , Sippl Christian
Published: February 2023

As the number of seismic stations and experiments greatly increases due to ever greater availability of instrumentation, automated data processing becomes more and more necessary and important. Machine Learning (ML)methods are becoming widespread in seismology, with programsthat identify signals and patterns or extract features that can eventually improve our understanding of ongoing physical processes.We here focus on critically evaluating the performance of a popular machine-learning-based seismic event detection and arrival time picking program, EQ-Transformer, forseismic data from the IPOC deployment in Northern Chile, using handpicked benchmark datasets.By using the open-source framework SeisBench, we can test the effect of using different pre-trained models as well as modify critical parameters such as probability thresholds.By performing this evaluation, we want to decide whether it is necessary to retrain EQTransformer with local data, or if its performance with one of the supplied pre-trained sets is sufficiently good for our purposes.We prepared alarge handpicked benchmark dataset for Northern Chile, which we use to find the optimal configuration of EQTransformer. For this benchmark dataset, we select a total of 35 days distributed throughout the 15 years covered by the IPOC deployment. Our goal was to pick all of the many small events in the dataset, even when they are only visible at one or two stations, with high accuracy. We found around three hundred events per day, which highlights the very high seismic activity of the region. We then ran EQTransformer for the same days, using a wide range of parameter choices and pre-trained models.We need to find if our data is similar to seisbench benchmark dataset or if we should use our data to calibrate the EQTransformer for picking in subduction zones.We use our handpicked benchmark dataset to evaluate the detection rate (missed events, false detections) as well as the picking accuracy (residuals to handpicks) achieved with EQTransformerin the various tested configurations. We present results of choosing different event detection thresholds, showingtrue positive rate vs. false positive rate plots in order to find optimal thresholds, and evaluate the pick accuracy of obtained arrival time picks by comparing to the handpicked benchmark. This comparison of picking times (P & S) is visualized with residual histograms. Lastly,we also show examples for a visual comparison of picks fromEQTransformer with manual picks.The present study is the first step towards the design of an automated workflow that comprises event detection and phase picking, phase association and event location and will be used to evaluate subduction zone microseismicity in different locations.
SAGE III/ISS v5.3 Level 2 Data Product Changes and Improvements
Authors: Hulsey Carter , Pitts Michael , Flittner David , Damadeo Robert , Manion Robbie , Larosse Marsha
Published: February 2023

The Stratospheric Aerosol and Gas Experiment on the International Space Station (SAGE III/ISS) is an occultation instrument that acquires measurements of aerosols and gases within the Earth’s stratosphere and upper troposphere. SAGE III/ISS provides level 2 solar species products for aerosol extinction (9 channels), nitrogen dioxide (NO2), ozone (O3), and water vapor (H2O). The level 2 products currently provide three O3 profiles based on differing retrievals. The first O3 profile is based on measurements at short wavelengths within the Hartley-Huggins band (MesO3), the second O3 profile is based on measurements made at visible wavelengths within the Chappius band (MLR O3), and the final profile is found using a more SAGE II like approach (AO3). The SAGE III/ISS also provides level 2 lunar species products for ozone (O3), nitrogen dioxide (NO2), and nitrogen trioxide (NO3). Version 5.3 of the SAGE III/ISS retrieval algorithm introduces improvements that affect the level 2 data products. The largest change to the solar algorithm is the implementation of disturbance monitoring package (DMP) corrections to improve pointing accuracy. The DMP is comprised of a miniature inertial measurement unit that measures rotation in inertial space using ring laser gyroscopes oriented about three orthogonal axes which can be used to correct pointing errors caused by mechanical disturbances. A major change common to solar and lunar algorithms is meteorological input from the coarser 42 level Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) model data to the 72 level MERRA-2 model data. The final major change involves improving the automated quality assurance (QA) algorithm to recover events that were withheld from the public release because differences between the AO3 and MLR O3 for some events after the eruption of Tonga–Hunga Haʻapai. Other changes for v5.3 include minor bug fixes as well as restoration of some data quality flags that were removed in v5.21. This presentation presents the impacts of these changes as well as overall observations of interest from v5.3 level 2 data products.
How does a denoising autoencoder improve earthquake detection and the estimation of magnitude in seismic networks?
Authors: Heuel Janis , Roßbach Meggy , Friederich Wolfgang
Published: February 2023

Seismogram records always contain seismic noise from different sources. Previous studies have shown that denoising autoencoders can be used to suppress different types of disturbing noise at seismological stations, even when earthquake signal and noise share common frequency bands. A denoising autoencoder is a convolutional neural network that learns from a large training data set how to separate earthquake signal and noise. To train the denoising autoencoder, we used earthquake signals with high signal-to-noise ratio from the Stanford Earthquake Dataset and noise from single seismological stations. We used 160 seismological stations in Germany and surrounding countries and trained a denoising autoencoder model for each station. Afterwards, one year of continuous recorded data have been denoised.EQTransformer, a deep-learning model for earthquake detection and phase picking, was then applied to the raw and denoised data of each station. Working with denoised data leads to a massive increase of earthquake detections. First results show that in dense seismic networks more than 100% additional earthquakes can be detected compared to events detected in the raw data set. Moreover, the localization accuracy is increased as more stations can be used.However, like common filter techniques, denoising autoencoders decrease the waveform amplitude. Since earthquake magnitudes are often determined from these amplitudes, we expect a lower amplitude and thus a lower magnitude when using denoised data instead of raw data. So far, we did not find an empirical relation between the raw and denoised magnitude.
Sub-kilometre resolution climate model data: Added benefits in the representation of extreme precipitation?
Authors: Dybro Thomassen Emma , Arnbjerg-Nielsen Karsten , J. D. Sørup Hjalte , L. Langen Peter , Olsson Jonas , A. Pedsersen Rasmus , B. Christensen Ole
Published: February 2023

Climate change impact on extreme precipitation is of great importance to society. Small-scale, short-term events can have massive social and socioeconomic consequences. The present study analyses a new sub-kilometre (750 m) HARMONIE-Climate1 model simulation driven by ERA5 reanalysis data. The new sub-kilometre climate model data (750 m) is compared to NorCP data2 from climate models in 3, 5, and 12 km grid spacing, rain gauge station data and reanalysis data in 31 and 79 km resolution. The study examines a case area covering Denmark for five cloudburst seasons (April – October). The study aims to analyse how convective events are represented in the climate model data across grid resolution, and if an added benefit can be identified moving to sub-kilometre resolution.Extreme convective events are analysed across datasets with respect to diurnal cycle, intensity levels and spatial structure. This is done at both hourly and sub-hourly scales. The 750 m climate model performs better for most metrics. However, climate models with 3 and 5 km grid spacing also perform well. The added computational and storage cost of the sub-kilometre scale experiments, thus only results in limited added benefit for this specific model set-up. Analysing hourly and sub-hourly temporal scales shows that the model performance varies between different temporal scales. The convection-permitting models, in general, represent hourly extremes much better than sub-hourly extremes. The sub-hourly scale is, therefore, essential to analyse to assess the model performance of convective events.1 Belušić D, De Vries H, Dobler A, Landgren O, Lind P, Lindstedt D, Pedersen RA, Carlos Sánchez-Perrino J, Toivonen E, Van Ulft B, et al (2020) HCLIM38: A flexible regional climate model applicable for different climate zones from coarse to convection-permitting scales. Geosci Model Dev 13:1311–1333. https://doi.org/10.5194/gmd-13-1311-20202 Lind P, Lindstedt D, Kjellström E, Jones C (2016) Spatial and Temporal Characteristics of Summer Precipitation over Central Europe in a Suite of High-Resolution Climate Models. J Clim 29:3501–3518. https://doi.org/10.1175/JCLI-D-15-0463.
Strengthening the bioeconomy in tropical countries while preserving soil organic carbon stocks by recycling recalcitrant coproducts: A case study for Ecuador.
Authors: Andrade Diaz Christhel , Baluganic Enrico , Zamora-Ledezma Ezequiel , Hamelin Lorie
Published: February 2023

Crop residues are a key supply of renewable carbon for the bioeconomy. However, the mobilization of crop residues from agricultural fields to the bioeconomy is commonly limited to 15-60% [1] of their technical potential to avoid depleting soil organic carbon (SOC) stocks [2]. Nevertheless, the coproducts remaining from several bioeconomy pathways are rich in recalcitrant carbon that could be returned to soils to maintain the SOC levels. In tropical countries, the great diversity of pedoclimatic conditions promotes the production of a vast variety of crops, which produce large amounts of residues that are commonly left unharvested or burned on the fields. This study investigates, for the specific context of tropical countries, the interaction between crop residue harvesting and long-term SOC dynamics when coproducts obtained from pyrolysis (biochar), gasification (char), hydrothermal liquefaction (hydrochar), and anaerobic digestion (digestate) are returned to soils. Besides the focus on tropical conditions, important novelties are that the soil carbon model RothC [3] was adapted to include extra pools representing the labile and recalcitrant (%CL and %CR) fractions of each coproduct, as well as their mineralization rates (kL and kR). In addition, the potential effect of coproducts in SOC mineralization, commonly referred to as priming effect (PE) was also included in the adapted model. The model was applied to the entire croplands in mainland Ecuador, used as a representative of tropical context given the availability of high spatial resolution data. Ecuador’s croplands were clustered in >105,000 simulation units, including 10 crops representing 95% of the total national production (i.e., banana, plantain, cocoa, coffee, oil palm, sugarcane, rice, maize, wheat, and barley). Simulations were carried out with our adapted RothC-bioeconomy model to compare, over 100 y (2020-2120), the four bioeconomy pathways studied herein to a reference scenario where crop residues are not supplied to the bioeconomy (unharvested). The climate variables used followed the RCP4.5 trajectory [4]. The spatially-explicit results, which are still being processed, describe the conditions and amount of crop residues that can be harvested for bioeconomy in order to maintain or increase long-term SOC stocks. [1] C. Andrade Díaz, et al., 2022. doi: 10.1016/j.apenergy.2022.120192. [2] H. Blanco-Canqui and R. Lal, 2009. doi: 10.1080/07352680902776507. [3] K. Coleman and D. S. Jenkinson, 1996. doi: 10.1007/978-3-642-61094-3_17. [4] IPCC, 2018.
Geological, geophysical and geotechnical highlights of the southern part of the Al Idrissi strike-slip fault system from the Alboran sea
Authors: Vidil Léa , d'Acremont Elia , Leroy Sylvie , Lafuerza Sara , Emmanuel Laurent , Rabaute Alain ,   ALBACORE and ALBANEO teams
Published: February 2023

In the Alboran Sea, oblique convergence between the African and Eurasian plates led to the establishment of the Al Idrissi sinistral strike-slip fault system, initiating a new plate boundary, 1 Ma ago. Several moderate magnitude earthquakes (Mw > 6) have been recorded on different segments of this fault system. The objective of this study is to analyse the dynamics of this plate boundary by studying the tectonic activity and physical properties of the sedimentary series along a key transect of the fault system. To do so, we used a panel of geological, geophysical and geotechnical tools, some of which were acquired during the ALBACORE oceanographic campaign (R/V Pourquoi Pas? 2021).The data analysed are derived from (i) sediment cores of the ALBACORE oceanographic cruise (with multi-sensor core logger - MSCL), (ii) heat flux measurements, (iii) penetration tests with the Ifremer Penfeld piezocone (CPTU) as well as (iv) multibeam bathymetry data and (v) seismic reflection/depth data. These data were acquired along a transect of the Bokkoya fault system, south of the Al Idrissi fault system. The length of the sedimentary series investigated allows the dating of major sedimentary events that occurred during the late Pleistocene and Holocene. Along this segment, isotope analysis of the carbonate biogenic components provided a 𝛿18O evolution curve that was converted into time series. Thus, a chronostratigraphic framework up to 80 ky could be constrained as well as variations in sedimentation rate between compartments on either side of the fault. The analysis of physical properties using heat flow, CPTU and MSCL data allows a detailed lithological and geophysical stratigraphy to be established along the transect and highlights the variability of geological, geotechnical and geophysical signatures on either side of the fault system.  This work is part of the ANR ALBANEO project, which aims to understand the dynamics of this new plate boundary and, in the longer term, to assess the hazards in this area of the western Mediterranean Sea.
Is the residual flow through the Marsdiep tidal inlet reversing?
Authors: van der Molen Johan , Groeskamp Sjoerd , Maas Leo
Published: February 2023

The western Dutch Wadden Sea is connected to the North Sea by two main tidal inlets: the Marsdiep in the southwest and the Vlie in the northeast. Along with strong tidal currents, there is a residual flow from the Vlie to the Marsdiep. We found that the direction of this residual flow is reversing.This residual flow has been studied since the 1970’s, with varying results for net volume fluxes. The driving mechanisms were identified as differences in tidal conditions in the main inlets, tidal rectification, and wind and atmospheric pressure. We analysed 13 years of ADCP observations collected on the ferry crossing the Marsdiep tidal inlet from 2009. The results are combined with earlier investigations covering the period 1998-2009. We find a significant trend in the magnitude of the residual volume flux, with decreasing export to the North Sea, and with occasional imports observed in recent years. We hypothesise that this trend is related predominantly to changes in North Sea tides, caused by increased strength and duration of stratification in response to global warming (Jänicke et al., 2021). With warming projected to continue, we expect the residual flow in the Marsdiep to continue to reverse to full inflow within the current decade, with potential knock-on effects for the sediment budget and ecosystem of the western Wadden Sea.This work was published in Ocean Sci., 18, 1805–1816, 2022, https://doi.org/10.5194/os-18-1805-2022. Jänicke, L., Ebener, A., Dangendorf, S., Arns, A., Schindelegger, M., Niehüser, S., Haigh, I. D., Woodworth, P., and Jansen, J.: Assessment of tidal range changes in the North Sea from 1958 to 2014, J. Geophys. Res.-Oceans, 126, e2020JC016456, https://doi.org/10.1029/2020JC016456, 2021.
Suitability of ocean reanalyses for monitoring of oceanic exchanges through the Indonesian Throughflow
Authors: Fritz Magdalena , Haimberger Leopold , Mayer Michael
Published: February 2023

The Indonesian Seas are characterized by numerous narrow channels connecting basins and seas of varying sizes and depths that serve as a transition between the Pacific and the Indian Ocean, known as the Indonesian Throughflow (ITF). The interaction between the ITF and important climate anomalies such as the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), or the Australian-Indonesian monsoon indicates the high relevance for monitoring the ITF region. In situ observations of ITF transports are highly valuable but are temporally and spatially limited. Hence, near real-time monitoring is only possible with reanalyses, yet their quality needs to be evaluated. Here we present an assessment of oceanic transports in the ITF diagnosed from the Copernicus Marine Service (CMEMS) Global Reanalysis Ensemble Product (GREP) and the higher-resolution product GLORYS12V1. Validation data comes from several moorings in Makassar strait, Lombok strait, Ombai strait, and Timor passage, obtained as part of the well-known INSTANT (2004-2006) and MITF (2006-2011 and 2013-2017 in Makassar) campaigns. The campaigns provide a total of 11.5 years of in situ observations in Makassar, therefore allowing the assessment of the mean seasonal cycle of ITF transport and a thorough investigation of the shorter sampled outflow passages. The results showcase that reanalysis-based volume transports agree reasonably well with in situ observations, however, some aspects, such as asymmetries in the flow through each strait, are more accurately represented by GLORYS12V1. Also, in terms of mean integrated transports, the increased horizontal resolution of GLORYS12V1 leads to a better performance in the narrower straits of Lombok and Ombai. Furthermore, we draw attention to an apparent one-month lag between reanalyses and observations in Makassar strait transports, which we assess by studying the influence of the monsoon-driven (vertically varying) pressure gradient on the ITF.
Understanding the impact of Hunga-Tonga undersea eruption on the stratospheric aerosol population using Balloon measurements, Satellite data, and model simulations
Authors: Vernier Hazel , Quintão Demilson , Biazon Bruno , Landulfo Eduardo , Souza Giovanni , J. S. Lopes Fabio , Rastogi Neeraj , Meena Rohit , Liu Hongyu , Fadnavis Suvarna , Mau Johnny , K. Pandit Amit , Berthet Gwenael , Vernier Jean-Paul
Published: February 2023

The stratospheric aerosol layer has witnessed large perturbations in the last couple of years. From extreme wildfires in North America and Australia to medium-size volcanic eruptions like Ambae, in July 2018, Raikoke, in 2019, and finally the Hunga-Tonga Ha’apai in January 2022. Reported as the largest marine eruption ever recorded, researchers used Microwave Limb Sounder (MLS) satellite data to reveal that this volcano injected the equivalent of 10% of the total stratospheric water vapor content (100 Tg) into the stratosphere. As a consequence, increased OH radicals from water vapor were reported to further reduce the SO2 lifetime by 50%.Here we outline the ionic composition, in parallel with microphysical, chemical, and optical properties of stratospheric aerosols using balloon measurements from Brazil 5-7 months after the eruption, in comparison with satellite data and model simulations. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and ground-based lidar measurements revealed the existence of a volcanic plume between 20 and 25 km. Particle size information derived from balloon-borne optical counters showed the presence of aerosols with a size radius >0.3µm and their subsequent sedimentation. In addition, ion chromatographic analysis of samples collected within the plume using a light-weight aerosol sampler revealed the presence of ammonia (0.3 ng/m3), sulfate (0.4 ng/m3), nitrate (1 ng/m3), and nitrite (1 ng/m3) in addition to Potassium (0.14 ng/m3), magnesium (0.12 ng/m3), and calcium (0.2 ng/m3). One of the striking findings of our measurements was the existence of traces of Dimethylamine (DMA) in our flights alongside the above-mentioned ionic components. DMA is known to enhance new particle formation upon reacting with H2SO4 and could have played an important role in the volcanic plume microphysical evolution. Although satellite data have revealed the presence of SO2 it is still uncertain if the SO2 only evolved from the Hunga-Tonga itself or as a consequence of a marine eruption that could have emitted Dimethylsulfuroxide (DMSO) into the stratosphere resulting in sulfate production.  
Using Deep Learning for Sentinel-1-based Landslide Mapping
Authors: Orynbaikyzy Aiym , Albrecht Frauke , Yao Wei , Plank Simon , Camero Andres , Martinis Sandro
Published: February 2023

Every year, landslides kill or injure thousands of people worldwide and substantially impact human livelihood. With the increasing number of extreme weather events due to the changing climate, urban sprawl and intensification of human activities, the amount of deadly landslide events is expected to grow. Landslides often occur unexpectedly due to the difficulty of predicting their location and timing. In such cases, providing information on the spatial extent of the landslide hazard is essential for organising and executing first-response actions on the ground.This study explores the advantages and limitations of using high-resolution Synthetic Aperture Radar (SAR) data from Sentinel-1 within a deep learning framework for rapidly mapping landslide events. The objectives of the research are four-fold: 1) to investigate how Sentinel-1 landslide mapping can be improved using deep learning; 2) to explore if the addition of up to three pre-event scenes could improve the SAR-based classification accuracies; 3) to test if and how much the addition of polarimetric decomposition features and interferometric coherence help to improve classification accuracies; 4) to test if performing data augmentation affects the final results.We adopt a semantic segmentation model – U-Net, and a novel deep network - U2-Net, to map landslides based on limited but globally distributed landslide inventory data. In total, 306 image patches with 128x128 pixels size were split into 80% for training/validation of the model and 20% for testing it. We calculate radar backscatter information (gamma nought VV and VH), polarimetric decomposition features (alpha angle, entropy, anisotropy) and interferometric coherence between temporally adjacent scenes. The features are calculated for three pre-event scenes and one post-event scene. Copernicus Digital Elevation Model (DEM) data are used to integrate land surface elevation and slope information into the classification process.Using all Sentinel-1 features, the best result of deep learning model obtained 0.96 for the Dice coefficient on validation data. The landslide detection based on U2-Net gave slightly better results than the U-Net-based approach. The accuracies of models based on one, two or three pre-event scenes did not substantially differ, indicating no added values of increasing pre-event SAR features. Higher accuracies were reached when polarimetric decomposition features were combined with interferometric coherence compared to runs with only radar backscatter. Increasing the sample size using image augmentation methods such as four-directional rotation and flipping helped advance the accuracy.Future research is directed towards (i) increasing and diversifying the landslide examples, (ii) performing landslide-events-based resampling and (iii) adding pre- and post-event optical data from Sentinel-2.  
The decreasing Chlorophyll-a in Tibet Plateau lakes during 1986–2021 based on Landsat image inversion and their impact causes
Authors: Zhu Liping , Pang Shuyu , Liu Chong , Ju Jianting
Published: February 2023

Lake chlorophyll-a (Chl-a) is one of the important components of the lake ecosystem. The Chl-a concentration of global water has generally increased in recent decades due to climate change and intensified anthropogenic activity. However, few researches have been done on the lake Chl-a variations in remote areas with less disturbance by human activities such as the Tibet Plateau (TP). Here, we combined 95 in situ measured lake Chl-a concentration data and Landsat reflection spectrum to establish an inversion model of Chl-a concentration through the backpropagation (BP) neural network prediction method, by which the mean annual Chl-a concentration in the past 35 years (1986–2021) of 318 lakes with an area of > 10 km2 in the TP have been retrieved. Meteorological and hydrological data, measured water quality parameters and glacier change in the lake basin were used to elucidate the driving factors of the Chl-a concentration changes in the TP lakes, with the help of geographic information system (GIS) technology and by spatial statistical analysis. The results showed that the mean annual Chl-a in the 318 lakes performed overall decrease during 1986-2021, but 63%, 32% and 5% of the total number exhibited no significant change, significant decrease and significant increase, respectively. After a slight increase during 1986–1995 (0.05 μg/L/y), the mean annual lake Chl-a significantly decreased during 1995–2004 (–0.18 μg/L/y). Further, after a slight increase during 2004–2011 (0.07 μg/L/y), it decreased slightly during 2011–2021 (–0.04 μg/L/y). The mean annual lake Chl-a concentration was significantly negatively correlated with precipitation (R2 = 0.48, P < 0.01), air temperature (R2= 0.31, P < 0.01), lake surface water temperature (LSWT) (R2 = 0.51, P < 0.01), lake area (R2= 0.42, P < 0.01) and lake water volume change (R2 = 0.77, P < 0.01). The decrease in mean annual Chl-a was in consistant to the decrease in that of salinity (R2= 0.69, P < 0.01) and increase in that of transparency (R2= 0.55, P < 0.01). The Chl-a concentrations of non-glacial meltwater-fed lakes were higher than those of glacial meltwater-fed lakes, except during higher precipitation period. Our result of lake Chl-a inversion and their variation reason analyses is able to further deeply understand the climate change impacts on Chl-a changes in the TP lakes.
Similarities and differences in groundwater responses to droughts across Germany
Authors: Ebeling Pia , Kumar Rohini , Chávez García Silva Rafael , Fleckenstein Jan H. , Musolff Andreas
Published: February 2023

Regional groundwater resources are crucial for water supply, maintaining environmental stream flows and the integrity of aquatic ecosystems. At the same time, however, these resources are increasingly threatened by the effects of climate change. More extreme weather conditions like exceptional droughts are expected to increase water stress by increasing water demand and decreasing water availability even in humid regions such as Germany. To identify consistent long-term trends and areas vulnerable to droughts, it is important to characterize and understand similarities and differences in groundwater dynamics across sites. Herein, we analyze groundwater head responses to climatic variability at more than 6500 groundwater wells over the last 30 years in Germany to identify response clusters. Principal component analysis (PCA) revealed that about two-thirds of the observed groundwater level variability across all wells can be explained by five typological time series. These time series represent different response patterns to climatic forcing capturing distinct dampening effects and time lags, with different weights (loadings) being assigned to each groundwater well. The subsequently identified clusters of the wells reveal clear regional structures suggesting underlying spatial controls. In the next step, groundwater drought characteristics (e.g., severity, duration) will be considered and linked to climate and landscape properties. This study may help to understand regional controls and to identify zones vulnerable to groundwater droughts where water supplies are at risk in the long term and mitigation measures are needed.
Satellite Remote Sensing and Hydrological Modeling for Estimating Daily Actual Evapotranspiration in a Semi-Arid Mediterranean Ecosystem
Authors: Awada Hassan , Castellini Mirko , Di Prima Simone , Giadrossich Filippo , Sirca Costantino , Marras Serena , Spano Donatella , Pirastru Mario
Published: February 2023

Evapotranspiration (ET) is the process by which water is lost from the Earth's surface through the combined mechanisms of evaporation from surfaces and transpiration from plants. It is an important factor in the soil-plant-atmosphere (SPA) system and plays a key role in the functioning of ecosystems. In semi-arid regions such as the Mediterranean, ET is a major contributor to water loss. An accurate understanding of the spatiotemporal dynamics of ET is crucial for effective water resource management and conservation, particularly in the face of increasing water resource pressure and potential climate change. Remote sensing (RS) can provide long-term data with relatively high spatial and temporal resolution, which can be valuable for sustainable ecosystem management. Surface energy balance (SEB) techniques based on satellite RS data have proven useful for quantifying actual evapotranspiration (ETa eb) at various temporal and spatial scales. However, limitations such as the temporal resolution of satellite data and gaps in image acquisition due to cloud cover can limit the usefulness of RS. This study proposes a model-based approach for constructing daily crop actual evapotranspiration (ETc act) between Landsat 8 acquisition days. The modeling approach aims to simulate the dynamics in the SPA system that occur between two Landsat acquisitions in order to estimate the daily time series of ETc act. The model integrates ETa eb estimates by SEBAL model on Landsat-8 acquisition days, RS-derived vegetative biomass dynamics, field measurements of potential evapotranspiration, and a hydrological modeling approach using the transient flow Richards equation to estimate soil moisture in the root zone. The results show that the proposed approach is well suited for modeling the dynamics in the soil-plant-atmosphere system that occurs between two Landsat acquisitions to estimate the daily time series of ETc act. This approach can provide valuable information for water resource management, drought monitoring, and climate change research, moreover accurate ETc act estimates can make significant contributions to near real time irrigation modeling and scheduling.
Deriving basin-wide denudation rates of basaltic rocks using cosmogenic Kr isotopes, vulcanic complex Vogelsberg, Germany
Authors: Niemeyer Sabrina , Wittmann Hella , Dunai Tibor J.
Published: February 2023

The Vogelsberg area in Hessen, Germany, comprises the largest contiguous volcanic complex in Central Europe, covering an area of about 2300 km². After volcanic activity ceased during the mid-Miocene, the complex was subject to extensive erosion and weathering. Fluvial erosion has shaped the area, which is now characterised by Pleistocene valleys and a radial river system exposing primitive alkali basalts and basanites. However, the inference of catchment-wide weathering and erosion rates from the most commonly used cosmogenic nuclide – mineral pair (e.g. 10Be from quartz) remains challenging in such an environment due to the mafic nature and nominally quartz-free composition of the local bedrock. Due to these method-related obstacles only few cosmogenic studies have focused on basaltic regions until now, even though basalt weathering is globally an important CO2 sink.The development and establishment of the novel method using terrestrial cosmogenic krypton (Kr) in the weathering-resistant mineral zircon (Dunai et al. 2022) allows quantification of denudation on quartz-poor lithologies over hundreds of kyr timescales. We exploit the method’s advantage and sampled zircons from sediments of streams radially draining the Vogelsberg and measured Kr isotope abundances to assess the time-integrated erosion patterns shaping the volcanic complex. Integrating over millennial timescales, the 10Be(meteoric)/9Be system will be applied to the same catchments. The 10Be/9Be system can be measured on sediment of any type of lithology including mafic rock (Dannhaus et al. 2018), and thus presents an inter-method validation of the Kr method. We will present the krypton results and discuss basalt weathering in a currently temperate climate through the lens of the different methodological approaches applied. Dunai et al. (2022) Geochronology, https://doi.org/10.5194/gchron-4-65-2022Dannhaus et al. (2018) GCA, https://doi.org/10.1016/j.gca.2017.11.005
Winter Warm Spells and snowpack ablation in western North America
Authors: Scaff Lucia , Krogh Sebastian , Musselman Keith , Harpold Adrian , Lillo-Saavedra Mario , Oyarzún Ricardo , Li Yanping , Rassmusen Roy
Published: February 2023

Winter warm spells (WWS) are extreme temperature anomalies that might impact the snowpack. WWS amplify snowmelt and sublimation in mountain regions with uncertain consequences to timing and volume of water resources. Most studies focus on the spring season when snowmelt rates and streamflow response are high. However, winter snowmelt events are important in places where the snowpack and air temperatures are closer to the freezing point during winter, and thus it will become important in other regions in a warmer climate.This study aims to understand the effect of WWS on snowpack ablation patterns in the mountainous western North America and how they might change under a warmer climate. For this, we use two convection permitting regional climate model simulations to represent historical (2001-2013) and future atmospheric and the surface conditions. The future simulation is performed with a Pseudo Global Warming approach for a high emission scenario (RCP8.5). We verify WWS using gridded maximum daily temperature observation, and winter ablation using snow pillows. Then we characterize WWS and relate them to snowpack ablation.Although days with ablation during WWS represent a small fraction (8.3%, 0.6 days on average), 55% of total ablation occurs during WWS over regions with significant snowpack (mean peak snow water equivalent over 150 mm). Consistently, a larger ablation rate (53%) is found during WWS than non-WWS events. Total ablation during WWS increases about 157% in a warmer climate; however, the extreme ablation (99th percentile) rates show slight decrease (5%). Classifying the domain based on its humidity and temperature, we found that ablation rates during WWS in humid regions are larger in a warmer climate than those of the dry regions, which is explained by the differences in the energy balance and the snowpack cold content. WWS predominantly drive snowmelt (93.8%) rather than sublimation (6.2%), which has relevance to water resources such as flood risk, soil moisture, and streamflow response. Furthermore, the median snowmelt rate during WWS found to increase in response to warming by 179% compared to the median sublimation rate (125%). This study provides a comprehensive description of the impact of extreme temperature events and a warmer climate over our changing snowpack. We acknowledge financial support by Centro CRHIAM Project ANID/FONDAP/15130015, and the Anillo project ACT-210080.
The Relationship Between Moderate Earthquakes and Ayazakhtarma Mud Volcano Using the InSAR Technique in Azerbaijan
Authors: Gadirov (Kadirov) Fakhraddin , Ahadov Bahruz
Published: February 2023

In this research, the Interferometric Synthetic Aperture Radar (InSAR) method is used to evaluate the connection between earthquakes and volcano dynamics in Azerbaijan. InSAR provides a robust technique for defining the complexity of earthquakes in spatial dimensions and provides more precise information about the effects of earthquakes than traditional methods. We assessed pre-, co-, and post-seismic scenarios to find the possible triggering relationships between moderate earthquakes and the Ayazakhtarma mud volcano. The Ayazakhtarma volcano is located 46 km from the 2021 Shamakhi and 67 km from the 2019 Basqal earthquakes, respectively. In this study, comprehensive deformation time series and velocities for the volcano using Sentinel 1A/B data between 2014 and 2022 were produced from LiCSAR products using LiCSBAS. At the same time, a radar line-of-sight (LOS) displacement map was generated based on results from the GMT5SAR for pre-, co-, and post-seismic deformation of earthquakes. Based on our observations of the following earthquakes, our results show that moderate earthquakes (Mw≤5) cannot trigger large mud volcano eruptions. In particular, the study of the Ayazakhtarma mud volcano revealed significant LOS changes that were positive and negative in the western half and eastern half of the site, respectively. Our research helps us comprehend how earthquakes impact eruptive processes. In two different situations, the interferograms enable the detection of ground displacement associated with mud volcano activity. At the Ayazakhtarma, faults also play a fairly important role in the deformation pattern. Interestingly, the observed fault system primarily exists in the region that divides sectors with various rates of subsidence. The interferometric data have been studied, providing new information on the deformation patterns of the Ayazakhtarma mud volcano.
Groundwater level prediction from meteorological indices
Authors: Iffland Ronja , Haberlandt Uwe
Published: February 2023

Due to climate change, an assessment of future changes in hydrological systems is necessary for appropriate planning, particularly for water management. So far, especially flood and low flow events have been studied. But groundwater levels are also influenced by extended dry periods and seasonal shifts in precipitation, as groundwater recharge is directly related to precipitation and evaporation. In the study area of Lower Saxony (Germany), groundwater is an important resource for drinking water and supplies about 86 % of the demand (MU 2021). Therefore, knowledge about possible changes is of highest importance for a possible need for action.In this study, climate characterising indices are used. Based on the assumed relationship between groundwater levels and meteorological indices, a simplified statistical approach should be used. Therefore, multiple linear regression models were set up for groundwater level estimation. Local models were set up for 734 groundwater monitoring wells in Lower Saxony, Germany. In order to take the persistence of the meteorological indices into account, moving averages and time lags were also included. Using a split validation procedure, which could be carried out for 114 stations with sufficient time series lengths, shows a good performance of the models. In order to make statements about future changes, the models were applied using climate model data based on the RCP8.5 scenario. Analyses for the reference period show that the groundwater levels can be sufficiently estimated. Slight changes were detected for the near future (2021-2050) and for the far future (2071-2100). For the majority of the measuring stations, decreases in mean annual low groundwater levels and slightly decreases in mean annual high groundwater levels are observed for both future periods. The number of low-level months does not change, while the number of high-level months increases slightly. In addition, a delayed timing of the annual extremes can be detected.
MD-BTES construction and integration into a district heating grid: Insights and targets of SKEWS and PUSH-IT projects
Authors: Bossennec Claire , Sass Ingo , Seib Lukas , Landau Matthias , Pham Tien Hung
Published: February 2023

Heat storage in crystalline basement rocks is a promising technology because it can provide a reliable source of heat and help to increase the efficiency of energy systems, and reduce greenhouse gas emissions. BTES systems work by circulating water in multiple borehole heat exchangers (BHE). However, BTES systems can be expensive to install, as they are sub-surface installations which require the drilling of medium-deep boreholes into often complex, sometimes fractured, heterogeneous lithologies.  Therefore, the geological uncertainties must be integrated from the early planning stage on.This contribution focuses on the insights gained in the SKEWS (Seasonal Crystalline Borehole Thermal Energy Storage) project (research project SKEWS, project administrator Jülich, funding code 03EE4030A) and how these will be developed and rolled out in the Horizon Europe PUSH-IT project into follow-up sites at the European scale. The SKEWS project implements the world’s first demo site for Medium-Deep Borehole thermal energy storage in crystalline rocks, with three 750 m deep boreholes separated from an 8.6 m distance, drilled at campus Lichtwiese from the Technical University of Darmstadt, Germany.From the drilling campaign carried out in the summer and autumn 2022, new insights have been gained into the implementation of BTES in such an urban environment. These insights go from the drilling technologies and verticality to the installation of the BHE. This knowledge and know-how will then be developed during the test phase and with the integration and surface connection of the BHE field with a section of the district heating grid.Borehole heat exchanger installation, with insights on the experience gained on the optimal design, drilling, and completion, will be detailed. The planning and first results of the reservoir test phase and monitoring through optic fibre will be presented, as well as perspectives on targeted digital twin geological static and dynamic modelling of the reservoir and the district heating grid in a co-simulation workflow.Such outputs will allow quantitative estimation of the technical and economic potential of the MD-BTES systems in existing or future district heating grids.
Reducing uncertainty of floating plastic transport estimates in rivers using the visual counting method
Authors: Mellink Yvette , van Langen Simone , Vriend Paul , Kamp Nadieh , de Weme Anne , van Emmerik Tim
Published: February 2023

Macroplastics have been found in many compartments of freshwater systems amongst which floating at the water surface. To quantify the floating macroplastic flux in rivers, the visual counting method was developed. This method is based on visual observations from bridges, and has already been applied in various river systems across the world, including the Rhine-Meuse delta. A two-year dataset of monthly field measurements on ten bridges across the Rhine, Meuse, and IJssel rivers has been collected. This dataset revealed the high variability of the floating macroplastic flux in both time and space. Except for extreme flooding events, the fluctuations are not always simply related to the discharge or season. This finding raises the questions of how to assure representative field observations. Representative field observations are important, as they are typically inter- and extrapolated in time and space. If the timing or location of the measurement is not representative of the ‘normal’ condition, then the extrapolation of that measurement will be associated with a large uncertainty range, resulting in over- or underestimations of the total floating macroplastic flux in the river. As field observations play a major role in calibrating and validating river plastic transport and emission models, it is essential to minimize the uncertainty of field-based floating plastic transport estimates. To optimize the visual counting method and explore its limits, we executed three experiments. The first experiment demonstrated that the temporal variability at bridge level is high, but can be attenuated by repeated measurements. The second experiment showed how many observation points on the bridge are sufficient to account for the spatial variability of the macroplastic flux across the river cross profile. The third experiment determined that the size limit of the visible macroplastics is 1 cm2 on bridges that are up to 5 meter above water level and 4 cm2 for bridges up to 15 meter above water level. The findings of these experiments endorse the effectiveness of the visual counting method and allow for a substantiated implementation of this method in floating macroplastic monitoring campaigns across river networks worldwide.
Investigating Convective Self-Aggregation in the Transition from Land to Sea
Authors: Kruse Irene L. , Haerter Jan O.
Published: February 2023

Within the atmospheric modelling community, a large focus in recent years has been on the concept of Convective Self-Aggregation (CSA): In an environment of radiative convective equilibrium, with homogeneous initial conditions and a constant-temperature tropical sea surface, convection can spontaneously aggregate into domain-wide patterns of persistent dry areas and constrained rainy areas over a temporal timescale of weeks to months. CSA, albeit still a modeling paradigm, could reveal the mechanisms behind some of the convective organization observed in the tropics.This process of forming domain-wide structure can be accelerated to the order of days by imposing oscillating surface temperatures with a large enough amplitude [1]. The ‘diurnally aggregated’ cloud field is similar to CSA as it also constrains the surface rain field to certain parts of the domain. Further, pattern formation was found to initiate first as persistent dry patches in the uppermost layers of the simulated atmosphere. The dry patches subsequently penetrate through to the subcloud layer [2].In this work we investigate how diurnal surface temperature amplitudes, typical of tropical land, affect the formation of persistent dry patches and the spatio-temporal extent of the emergent mesoscale convective systems. We run a set of cloud resolving simulations initialized with typical profiles of temperature and humidity. We impose a large-amplitude diurnally oscillating surface temperature, which we then set to constant at different times, to see the effect on the diurnally aggregated cloud field. We present the results of this study, which show a strong dependence on the degree of aggregation over ‘land’, in determining the aggregation over ‘sea’, and a form of hysteresis arises. 1. Haerter, Jan O., Bettina Meyer, and Silas Boye Nissen. ‘Diurnal Self-Aggregation’. Npj Climate and Atmospheric Science 3, no. 1 (30 July 2020): 1–11. https://doi.org/10.1038/s41612-020-00132-z.2. Jensen, Gorm G., Romain Fiévet, and Jan O. Haerter. ‘The Diurnal Path to Persistent Convective Self-Aggregation’. Journal of Advances in Modeling Earth Systems 14, no. 5 (2022): e2021MS002923. https://doi.org/10.1029/2021MS002923. 