bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid water content in a seasonal snowpack: a comparison between satellite products and model simulations
Authors: Cazzaniga Greta , Arslan Ali Nadir , De Michele Carlo
Published: February 2023

The spatial and temporal quantification of the liquid water content (LWC) of the snowpack in alpine regions provides information on the short-term availability of water, which could eventually lead to wet snow avalanches or river floods. The monitoring and forecasting of snow wetness are hence of paramount importance in many fields, from operational avalanche forecasting to hydropower production and flood prediction, when combined with hydrological models. Remote sensing is an essential tool for snow monitoring as it offers observations of the snowpack's physical properties. For instance, Sentinel-1 satellites provide C-band synthetic aperture radar (SAR) data at high temporal and spatial resolutions and are capable to detect the presence of wet snow.  On the other side, many snow models were built in literature to simulate snowpack mass dynamics in space and time (see e.g., Crocus and HyS model) and can provide predictions of variables of interest in snow hydrology, such as the LWC. In the present work, we aim at identifying and quantifying the differences between satellite products and model snow estimates. In particular, the comparison is led among (1) Sentinel-1-based wet-snow products, (2) HSAF products, coming from the processing of data from Earth observation satellites and revealing the wet or dry status of the snow mantle, and (3) simulations of the liquid water content from HyS model, a temperature-index model, leveraged in both its one-layer and two-layer version. The case study is the Mallero basin, a middle-size alpine basin, whose flow regime is strongly influenced by snow melting and glacier ablation in the spring and summer seasons. The comparison returns a good agreement between Sentinel-1 products and HyS simulations. The short period of mismatches between the two outputs is analyzed to identify the physical processes that the model is not able to reproduce. On the other side HSAF products have a coarser resolution if compared to Sentinel-1 products and for this, they can just provide a qualitative overview of the snow mantle status, over a middle-size basin. Moreover, such products are also limited by the effect of cloud covering that makes it impossible to have information on the snow wetness when it is present.
Initial Orbit Determination Results from the University of Luxembourg using Spire GNSS Tracking Data
Authors: Shafiei Parisa , Bemtgen Jean , Talpe Matthieu , Tabibi Sajad
Published: February 2023

CubeSats constellations using commercial off-the-shelf components have been studied for different applications, such as GNSS Radio Occultation (GNSS-RO). Furthermore, precise orbit determination of Low Earth Orbit (LEO) CubeSats based on multiple GNSS constellations would open new opportunities for scientific applications such as Earth’s gravity field measurements.In GNSS kinematic orbit determination, which is the common method used for small sats, the derived orbits are affected by noise, data gaps, outliers, measurement errors as well as poor geometry of the observations. Our work seeks to mitigate these issues and we present two areas of research: 1) GNSS network processing of GPS and Galileo constellations and 2) kinematic orbit determination of a set of Spire CubeSats that host a GNSS-RO payload. An initial architecture of kinematic orbit processing for the Spire GNSS-RO CubeSats constellation is obtained and the details on validations and limitations are discussed in more details. In addition, we showcase the agreement between the GNSS orbit products produced at the University of Luxembourg (UL) with those of the Center for Orbit Determination in Europe (CODE). Finally, the Spire kinematic orbits based on the raw observation approach are derived and compared to the L1B Spire orbit products.
Impacts of tidally-driven mixing on the Early Eocene Ocean
Authors: Ladant Jean-Baptiste , Millot-Weil Jeanne , Donnadieu Yannick , de Lavergne Casimir , Green Mattias
Published: February 2023

Mixing in the ocean interior is largely fueled by internal tides that bring energy available for the irreversible mixing of the deep ocean. However, the inclusion of mixing schemes to represent the breaking of internal waves is not always included in ocean and earth system models, a fortiori in models applied to the deep-time for which estimates of the energy dissipated by the tides are not always available. Here, we present and analyze two IPSLCM5A2 earth system model simulations of the Early Eocene made under the framework of DeepMIP, which differ by the inclusion of the tidally-driven dissipation estimates of Green and Huber (2013) in one of the simulations. We particularly focus on possible changes in the intensity of the ocean circulation and water mass characteristics and pathways as well as on the implications of the absence of tidally-driven mixing for the marine biogeochemistry.
Toward the systematic exploration of the seabed morphology during transits after the ISOBatA project experience in the Southern Ocean
Authors: Accettella Daniela , Burca Mihai , Cuffaro Marco , Diviacco Paolo , Gasperini Luca , Lodolo Emanuele , Muccini Filippo , Savini Alessandra , Varzi Andrea Giulia
Published: February 2023

Transits during oceanographic expeditions constitute a potential huge amount of acquired bathymetric data that could be systematically integrated to increase the knowledge on submarine morphology, especially for planned surveys in the equatorial Atlantic, the Arctic, the Indian and the Southern Oceans. The recent PNRA ISOBatA project aims to efficiently exploit seaﬂoor datasets collected during transfer times within the Antarctic region and the Ross Sea. Along the route from New Zealand to the Italian Mario Zucchelli Station in the Ross Sea, the Emerald Fracture Zone and the Macquarie Triple Junction, located in the SW Pacific Ocean, represent two selected areas to test the strength of transit acquisition in remote areas, normally affected by adverse weather conditions.
 
The ISOBatA project has the main purpose to contribute to the mapping of Antarctic waters developing best practices and dedicated workflows to implement QA in multibeam data acquisition procedures during transit times, as well as in the processing, analysis and archiving of data and metadata.
The ISOBatA experience in the Southern Ocean suggests there are several critical issues associated with collection of multibeam data in remote and ice-infested waters. Operating procedures need more standardization, to avoid the acquisition of redundant data along common routes and unreliable data.
Our work aims to open a discussion to address the need for standardization in data acquisition during transit times, which should include priority in accordance with the geomorphological/geographical nature of the working areas. The integration of bathymetric data acquired during research vessel transfers to remote regions could imply a common international effort for a systematic exploration of the seafloor, sharing coverage in real time to avoid redundancy.
Sentinel-5P TROPOMI NO2 reprocessing v2.4.0: Impact of the surface albedo
Authors: Eskes Henk , van Geffen Jos , Boersma K. Folkert , Tilstra Gijs , Sneep Maarten , Veefkind Pepijn
Published: February 2023

The Sentinel-5P TROPOMI instrument provides unique observations of atmospheric composition at a high spatial resolution of about 5 km with near-daily global coverage. A new mission reprocessing of all official data products for the full operational phase (30 April 2018 until the present) is currently being generated, co-ordinated by ESA, and is expected to become available in March/April 2023. For NO2 this reprocessing will result in a uniform dataseries for the full mission based on processor version 2.4.0 and on version 2 level-1B input data. The reprocessing is replacing the currently available data record for NO2, based on processor versions 1.2 x, 1.3.x, 1.4.0, 2.2.0 and 2.3.1. The upgrades to v1.4 and v2.2 involved major upgrades. Validation activities indicated that the older versions 1.2 and 1.3 had a low bias, a problem which was (at least partly) resolved by introducing v1.4 and v2.y. However, this also implies that trend studies are severely hampered by the jumps in the data series resulting from this sequence of updates. In order to support COVID-19 lockdown air pollution studies an intermediate "PAL" reprocessing of NO2 was made available in December 2021 based on the v2.3.1 NO2 processor and v1 L-1B data (https://data-portal.s5p-pal.com/products/no2.html).  The new official reprocessing with v2.4.0 and v2 L-1B will replace this PAL dataset. The new official reprocessing is expected to be of great use for studying the inter-annual variability in NO2 in recent years.  The major change in v2.4.0 compared to v2.3.1 is the replacement of the surface albedo datasets with a directional (viewing-angle dependent) Lambertian equivalent reflectivity (DLER) database derived from TROPOMI observations. Before the TROPOMI NO2 processor made use of the OMI (for the NO2 fitting window) and GOME-2 (for the O-2A band spectral region used for the cloud retrieval) LER. The use of the TROPOMI DLER is especially important for the cloud fraction and cloud pressure retrievals, because the clear-sky reflectivity in the NIR is very sensitive to the (viewing) geometry. In our contribution we will present the new reprocessed TROPOMI NO2 v2.4 dataset and quantify the impact of the use of the TROPOMI DLER on the cloud properties, air-mass factor and tropospheric NO2 column. 
Simulation of the hydro-acoustic and gravity waves generated by a landslide
Authors: Dubois Juliette , Impériale Sébastien , Mangeney Anne , Sainte-Marie Jacques
Published: February 2023

In this work we propose a linear model describing the propagation of acoustic waves and gravity waves in the ocean. This model can be used for describing the propagation of a tsunami and the acoustic waves generated by an underwater earthquake or a landslide.
The acoustic-gravity waves are considered as first order perturbation of an equilibrium state for the ocean. The equilibrium state is as follow: there is no mean current and the pressure, temperature and density are vertically stratified. The model is obtained from a linearization around this equilibrium state of the compressible Euler equations. Unlike several other works on acoustic-gravity waves, the two types of waves are not decoupled during the linearization. The complete derivation of the model and the comparison with the other models of the literature are presented in [1].
As a first application we present the simulation of a simplified landslide. We aim at a better understanding of the acoustic wavefield generation process. The equations are discretized with the finite element method in space and a finite difference scheme in time. In-field data on the acoustic waves generated by a landslide are already available in the literature [2] and provide the relevant scales for the simulation.
[1] Juliette Dubois, J., Imperiale, S., Mangeney, A., Bouchut, F., Sainte-Marie J. (2022), Acoustic and gravity waves in the ocean: a new derivation of a linear model from the compressible Euler equation, Submitted.
[2] Caplan-Auerbach, J., Dziak, R. P., Bohnenstiehl, D. R., Chadwick, W. W., and Lau, T.- K. (2014), Hydroacoustic investigation of submarine landslides at West Mata volcano, Lau Basin, Geophys. Res. Lett., 41, 5927– 5934, doi:10.1002/2014GL060964.
Pleistocene Landscape Evolution in Southern Patagonia: A Record of Regional Incision from 10Be Dating of Fluvial Terraces
Authors: Milanez Fernandes Victoria , Schildgen Taylor , Ruby Andreas , Wittmann-Oelze Hella , McNab Fergus
Published: February 2023

Glacial and fluvial landforms record the recent history of Earth’s surface, and hold information on the climatic or tectonic processes that shape the landscape. Southern Patagonia hosts uniquely well-preserved fluvial cut-and-fill terraces. A record of fluvial incision since 1.5–4 Ma is preserved from K-Ar dated basalt flows atop relict paleosurfaces, and published regional thermochronometric dating and modelling suggest an increased phase of exhumation in the last 1–3 Ma. However, few constraints exist on the onset of river incision, which might provide clues as to possible drivers of regional landscape change. To constrain the timing of Pleistocene incision and landscape evolution in southern Patagonia, we present new cosmogenic 10Be exposure ages of surface cobbles and amalgamated pebbles from fluvial terraces in the Tres Lagos region 50ºS) and the Río Santa Cruz. Locally, dated basalt flows set a maximum age of ~2.2 Ma for the Tres Lagos terraces, and between 2.2 and 1.7 Ma in the Condor Cliffs region of the Río Santa Cruz. Preliminary 10Be ages for terrace surfaces in the Tres Lagos region reveal ages between 45–845 ka. Ages of upstream fluvial terraces of the Río Santa Cruz reveal ages between 290–830 ka. The sequence of terrace ages shows that the phase of net incision started ca. 1 Ma after widespread emplacement of basalts, concomitant with enhanced climatic forcing following the Mid-Pleistocene Transition. Ages are also in agreement with the incision history recorded in dated fluvial terraces of other Patagonian rivers, notably the Río Deseado, where ages range from 400 ka–1 Ma (47ºS; Tobal et al., 2021). We argue that the combined results suggest that this net-incisional phase was widespread, therefore unlikely to result from local tectonic drivers, hence probably climatically driven. Our record of Pleistocene landscape evolution is similar to other records throughout the Andes, where the timing of fluvial incision has been linked with the transition to enhanced climatic forcing after ~1 Ma (e.g., Central Andes). Our results point a strong influence of the Mid-Pleistocene Transition on landscape evolution on a continental scale, and notably also in the southernmost regions of South America.
Agricultural terraces in the UK, new insights from biogenic microremains.
Authors: Alonso Eguiluz Mónica , Albert Rosa María
Published: February 2023

Agricultural terraces are anthropological features that shape the landscape. In Europe, their construction and use dates back to the late Neolithic and today they can be documented across the continent corresponding to different chronological periods. In addition to the impact on the landscape and the environment, the possibility of expanding the production area, through the construction of terraces, makes it possible to improve the quality and diversity of the crops produced, thus contributing to increasing demographic and social complexity. To better understand the role of agricultural terraces in the environment and society, the TerrACE project has developed a high-resolution research protocol to be applied to different agricultural terrace systems in Europe without chronological distinction. This multi-proxy research includes, among others, the analysis of biogenic microremains to identify past cultivars.We focus here on the use of biogenic microremains (phytoliths, diatoms, ash pseudomorphs, and faecal spherulites) and FTIR analysis applied to four agricultural terraces from the United Kingdom, with different chronologies: on the one hand, the prehistoric terraces of Plantation Camp and the medieval terraces of Gueswick both in northern England, 72 km apart; and on the other hand, the prehistoric terraces of Charlton Forest and Blick Mead both in southern England, 78 km apart. In addition to evaluating exploited cultivars, we also seek to identify differences and similarities between these sites. While ash pseudomorphs and fecal spherulites were not documented at any of the sites, phytoliths were well preserved at Plantation Camp, Gueswick, and Charlton Forest. In general, it can be observed that the amount of phytoliths decreases with depth. Along with the phytoliths, diatoms have been identified, although to a lesser extent. The most abundant phytoliths were those produced by grasses, especially those of the C3 Pooideae subfamily. Even though evidence of crops is scarce, analyzing the short silica short cells phytoliths we were able to identify barley in Plantation camp, which agrees with its location and chronology. These same analytics, along with complementary methods (i.e., DNA), are being conducted in the other sites to obtain more information regarding the plants cultivated in the terraces.
Exploring the particle size effect on the geochemical composition using experimental soil mixtures
Authors: Latorre Borja , Gaspar Leticia , Lizaga Iván , Blake William , Navas Ana
Published: February 2023

The impact of particle size on elemental content in soils is difficult to predict because the positive linearity between them does not apply equally to all elements. This assumption needs to be constantly examined and considered for fingerprinting studies. Overall, higher element enrichment in the fine fractions reflects the increasing adsorption potential of larger specific surface area (SSA), however, this relationship is often non-linear or more complex. Previous studies have been reported that the relationship between SSA and elemental geochemistry is different in terms of linearity, magnitude, and even direction for each element, and it could also depend on the type of sample. Fingerprinting approach is founded on the assumption that the properties of source and sediment mixtures are directly comparable, however, when a particle size correction (PSC) is needed because of the enrichment of sediment mixtures in fine particles, the use of a single PSC factor based on SSA could negatively affect unmixing results. Based on our previous study, in which we examined the behavioural characteristics of geochemical tracers in artificial mixtures with different grain size, we demonstrated that the source apportionment estimated with unmixing models was sensitive to particle size. In this contribution, we explore in detail, and tracer by tracer, the effect of the particle size variation on the correct estimation of source apportions. Artificial mixtures with known percentages contribution from three experimental sources have been used, comparing i) sources and mixtures at <63 μm, ii) sources at <63 μm and mixtures at <20 μm simulating fine enrichment and iii) sources at <63 μm and mixtures at <20 μm with particle size correction factor (PSC). These results support the need to develop alternatives to improve the use of correction factors in fingerprinting studies.
Role of root hairs in rhizosheath aggregation and in the carbon flow into the soil
Authors: de C. Teixeira Pedro Paulo , Trautmann Svenja , Buegger Franz , J.M.N.L. Felde Vincent , Pausch Johanna , W. Müller Carsten , Kögel-Knabner Ingrid
Published: February 2023

Plants' roots promote changes in soil structure, forming a strongly-bound soil layer in the surroundings of the root, which is named as rhizosheath. Rhizosheath formation is attributed mainly to the root hairs' presence, that favors the enmeshment of the soil particles around the roots, and the release of mucilage and exudates, which acts as gluing agents of those soil particles. In the present work, we studied the rhizosheath aggregate formation of two Zea mays L. genotypes with contrasting root hair development: a mutant with root hair defective elongation (rth3) and a corresponding wild type (WT). We also tracked the fate of recently-deposited C in the rhizosheath aggregates using two 13CO2 pulse labeling approaches (single vs. multiple pulse labeling). The sampled rhizosheath aggregates were further separated using dry-sieving fractionation into three aggregate size classes: primary small particles and smaller microaggregates (<53 µm), larger microaggregates (53-250 µm) and macroaggregates (>250 µm). We observed that the aggregate size distribution followed the same pattern in both genotypes. This result reinforces the assumption that other soil properties are more important for rhizosheath aggregation than root hair elongation. We observed that the higher potion of the recently-deposited root-derived C (57%) was accumulated in the macroaggregates. Moreover, the multiple pulse labeling approach proportioned a higher 13C enrichment of the rhizosheath aggregates fractions than applying a single pulse. Despite both single and multiple labeling approaches have resulted in a similar distribution of 13C in the rhizosheath aggregates, multiple pulse labeling provided a higher enrichment in the rhizosheath aggregates, which allowed a better separation of significant differences between the genotypes.
On-demand flood predictions and warnings with high-resolution weather and hydrological models: the case of Vejle, Denmark
Authors: Plum Charlotte , Martinsen Grith , Dybro Thomassen Emma , Wied Pedersen Jonas , Brian Butts Michael
Published: February 2023

Floods are often caused by small-scale weather and hydrological phenomena that require very high-resolution models to adequate resolve and simulate. Unfortunately, high-resolution models are expensive to run continuously in real-time, which makes the case for only running these specialized systems “on-demand” when it is deemed necessary. The aim of this study is to investigate a high-resolution digital twin designed for on-demand use and test it on the case of Vejle, Denmark. The city of Vejle is of special interest because it is prone to frequent floods from long-term winter precipitation, convective cloudburst events in summer as well as storm surges from the sea. On top of this, several fast and slow responding rivers meet inside the cityHere, we present results from a hydrological forecasting setup based around the conceptual HYPE model, which is developed by the Swedish Meteorological and Hydrological Institute. The model is developed with high-resolution soil and land use data, forced with high-resolution meteorological observations, and its predictions are evaluated at several gauges along the Vejle and Grejs rivers. The final aim of the research is to assess the benefits of utilizing subkilometer-scale HARMONIE weather predictions, which especially is expected to improve the resolution of local rainfall fields. The full forecasting chain will be put into operation in the coming year.
Experimental Investigation of Flow-Turbulence Behaviour in a Channel with Vegetated Mid-Bar
Authors: Krishnan U Ajay , Kumar Paswan Abhishek , Kumar Nandi Ketan , Dutta Subashisa
Published: February 2023

Compared to straight and meandering rivers, turbulent flow features around a mid-channel bar in braided rivers are far more complex. It is believed that the continuous expansion of these bar deposits causes the commencement of braiding. This article will therefore address the turbulent flow characteristics around mid-channel bars. In an experimental flume, a scaled-down physical model of a mid-channel bar deposit is built to examine the flow structure. Although the geometry of mid-channel bar deposits is not uniform, an elliptical shape is suggested here for simplicity. Rigid cylindrical vegetation is planted over the bar with submergent and emergent flow condition. An Acoustic Doppler Velocimeter (ADV) has been used to measure the three dimensional velocity component. Results indicate that the fluvial process associated with the flow is greatly influenced by flow velocity and turbulent kinetic energy. A flow divergence above the bar head and a flow convergence at the bar tail make up the bulk of the flow structure. Near the upstream end of the bar, adjacent regions are where the flow is perceived to accelerate. The bar's existence reduces the flow area nearby, leading to increased velocity in parts close to the upstream end of the mid-channel bar. The velocity was reduced by 15 to 20% from upstream section to downstream section of the bar. The velocity incriment was observed to be about 10% in vegetated conditon as of non-vegetated condition. Additionally, it has been observed that the momentum exchange is higher in the top of canopy and gradually reduces as it approaches the lower canopy and bar level. The findings obtained from this study can further utilized to examine braid bar occurrences in alluvial rivers to build an appropriate response through training techniques.Keywords: Braiding, Flume, Mid-Channel Bar, Turbulent Flow, Rigid Vegetation
Simulation of different georeservoir conditions on a highly-permeable sandstone
Authors: Fazio Marco , Sauter Martin
Published: February 2023

Studying the mechanical and hydraulic behaviour of rocks at different depths is crucial to understand their potential as georeservoirs. In particular, permeability and porosity are affected by changing conditions and their values measured at surface do not represent the real value at a certain depth. Mostly rocks with low or intermediate permeability have been tested in this regard. Here, instead, we focus on a highly porous and permeable rock (approximately 25% and 1000 mD respectively): Bentheim sandstone.Because of its petrophysical properties Bentheim sandstone is regarded as a reference rock material in laboratory experiments of rock mechanics: it is quasi monocrystalline (quartz up to 97%), with a well-sorted grain size distribution and well-connected pores, showing lateral continuity and homogeneous geometric, hydraulic and mechanical properties at the block scale.Unsurprisingly, Bentheim sandstone, as a georeservoir, has been extensively tested in triaxial conditions for a variety of purposes, from oil and gas exploitation to geothermal energy and carbon storage and sequestration projects. In fact Bentheim sandstone is taken into consideration as a potential warm aquifer for low-cost geothermal energy and for studying anhydrite cementification in georeservoirs. Since Bentheim sandstone can be found at more than 2 km deep and has been previously buried down to 3.5 km, it is important to fully understand its behaviour at different pressure, temperature, hydraulic and stress-hystory conditions.Previous laboratory studies have shown how the permeability of Bentheim sandstone is affected by effective confining pressure, bedding orientations and axial strain. In particular, it has been observed that an increase in effective pressure, corresponding to an increase in depth, does not influence the permeability of this sandstone. In reservoir geomechanics, this is a crucial finding. However, rocks at depths also experience different temperature and fluid pressure conditions, as well as different types of historic stress evolution. Although, general relationships between permeability and these parameters do exist, their specific effect on Bentheim sandstone has never been investigated in detail.Based on triaxial experiments in a state-of-the-art apparatus, we demonstrate on large cylindrical samples the behaviour of Bentheim sandstone for quasi reservoir conditions. Our goal is to fill in the gap in understanding the hydromechanical behaviour of this highly-permeable rock and concomitant permeability changes at different georeservoir conditions, where a suite of geomechanical parameters is investigated.
Long- and Short-term Damage Changes on Antarctic Ice Shelves
Authors: Izeboud Maaike , Lhermitte Stef
Published: February 2023

The contribution of the Antarctic ice sheet to sea level rise remains uncertain due to the potential instability of ice shelves. Damage areas in the shear zone of an ice shelf are a first sign of mechanical weakening, which can lead to speed-up of the ice and additional damage development. This damage feedback can precondition ice shelves for disintegration and enhanced grounding line retreat but remains one of the least understood processes, mainly since we lack a quantification of damage and its changes on large spatiotemporal domains.Recent efforts have resulted in a new, automated approach to detect damage. The NormalisEd Radon Transform Damage (NeRD) detection method allows to robustly detect damage features from multi-source, high-resolution satellite imagery. We have made both long-term (25 years) and short-term (annual) assessments from SAR images, based on both RAMP Radarsat (1997) and Sentinel-1 datasets (2015-2021).We produce, for the first stime, damage state and damage change maps of Antarctic ice shelves. Over the past two decades we detect a general damage increase on ice shelves, most evident on fast flowing ice shelves in the West Antarctic (Thwaites, Pine Island, Crosson) and the Peninsula (Wilkins).  On short time scales the detected damage changes are governed by new damage development versus calving events, imposing fluctuations on its increase or decrease from year to year. A strong decrease in damage is observed on ice shelves that have retreated significantly, thereby removing all damaged parts. This gives attention to small, retreated ice shelves that are otherwise overlooked.  We furthermore detect areas with stable damage states across the Antarctic. We detect this for both initially intact and initially damaged ice shelves, showing that the amount of damage itself is no indication for damage-induced instability.Our results provide new insights in Antarctic wide damage change, identifying regions that are (not) sensitive to a potential damage feedback and/or are vulnerable to retreat in combination with other forcings such as ocean warming or surface melt.  This large-scale damage change assessment is a first and important step in identifying ice shelf weakening and potential instability.
MDE-Thredds: A Django-based plugin for managing THREDDS data server
Authors: Hadizadeh Mostafa , Sommer Philipp S , Lorenz Christof , Baldewein Linda
Published: February 2023

The Thematic Real-Time Environmental Distributed Data Services (THREDDS) Data Server is an open-source, Java-based web application that enables metadata and data access to scientific netCDF datasets. In recent years, more and more research institutes implemented THREDDS to give researchers and other end-users access to a wide range of real-time and archival data sets from earth system sciences. A number of features and interfaces are provided by THREDDS that facilitate the interactive and automated exploration, standardization and use of data like the automated generation of ISO-formatted metadata files or the provision of OGC-services (WMS and WCS). However, the configuration of THREDDS via XML-catalogs remains difficult and is usually restricted to system admins. And particularly the publication and consistent maintenance of a large number of datasets is prone to errors and hence proves to be difficult and time-consuming. Within the Model Data Explorer (MDE, https://model-data-explorer.readthedocs.io), a cross-institutional project to simplify a FAIR publication of model data on the web, we develop a module to overcome these configuration issues and enable scientists to make their environmental research data available on the web. This MDE-THREDDS module manages the catalogs and configurations of the THREDDS data server by providing a user-friendly web-interface for handling major components of THREDDS, including catalogs and web services. A flexible permission system enables scientists and other data producers to add and update their own datasets without the need for manually editing the underlying THREDDS catalogs. This permission system further allows server administrators to moderate and facilitate the publication of data on the web by scientists and other end-users which, hence, ensures a standardized and consistent THREDDS catalog infrastructure.Overall, with MDE-THREDDS, we want to give scientists and other data producers a simple and user-friendly framework for making their research data open and FAIR through a wide range of standardized and well-established web interfaces.
Mapping Our Technosphere: what questions make it (and our biosphere) more sustainable?
Authors: Singer Katie
Published: February 2023

What questions can clarify our thinking so that we understand our technosphere more fully and can actually reduce our ecocidal impacts? Starting by naming our assumptions, say that our biosphere is the world of flora and fauna that can reproduce and biodegrade. Say that our technosphere is anything fabricated—including the Internet, motorized vehicles of all kinds, solar PVs, industrial wind turbines and battery energy storage systems. What are the technosphere’s main energy guzzlers? What kind of water use, extractions, greenhouse gases, electromagnetic radiation, abusive labor practices and toxic waste are involved in manufacturing, operating and discarding the technosphere? What regulations could promote safety and limit ecocidal growth? Katie Singer will sketch what we take from the biosphere to manufacture, operate and discard our technosphere. She’ll propose questions and activities for reducing our digital footprint. For example, could every smartphone user trace the supply chain of one substance in their smartphone or laptop—and share their research? 
On the role of Black Sea Waters in controlling the North Aegean buoyancy fluxes
Authors: Petalas Stamatios , Tragou Elina , Mamoutos Ioannis , Zervakis Vassilis
Published: February 2023

Understanding the processes that control the buoyancy fluxes of the Aegean Sea is important for various reasons. First, the Aegean is directly connected with the Black Sea and acts as a buffer between two opposite thermohaline systems, a concentration and a dilution basin (the Mediterranean vs the Black Sea), receiving and filtering the variability and changes of a much broader geographical area. Second, the Aegean is capable to produce large amounts of very dense water, having temporarily been the major originator of Eastern Mediterranean Bottom Water. These processes are controlled by the buoyancy fluxes, both through oceanic advection and atmospheric exchanges. In this work we examine the characteristics and variability of heat, freshwater and the overall buoyancy air-sea fluxes, focusing on the potential role of the interaction with the Black Sea. A thirty-year-long simulation (1985-2015) of the whole Eastern Mediterranean/Black Sea system, forced by ERA-Interim data, was used to estimate and analyze the seasonal and interannual variability of the buoyancy fluxes in the North Aegean. The climatological mean buoyancy flux over the North Aegean has been estimated to be about –10×10–6 kg m–1 s–3 (loss to the atmosphere). However, in the absence of Black Sea Water (BSW) inflow, the buoyancy loss would correspond to the high values observed over the Eastern Aegean, an area not directly affected by the presence of the BSW, i.e. about –30 ×10–6 kg m–1 s–3. It should be noted that the heat loss of the Aegean Sea to the atmosphere is much higher than all neighboring seas, including the Adriatic, the dominant dense-water formation site for the Eastern Mediterranean. Our analysis reveals that the thin surface layer of modified BSW acts as a moderator of the buoyancy loss from the upper water column. This layer not only absorbs the air-sea fluxes (acting as an effective insulator regarding dense-water formation processes), but also moderates or even reverses the buoyancy fluxes over its path. Thus, in addition to the significant lateral buoyancy input to the basin by the Black Sea inflow, an additional mechanism of reduction of winter heat losses to the atmosphere contributes to the control of dense water formation processes.
Conceptual and numerical modelling of the Versilia coastal aquifer (NW-Tuscany, Italy) for quantitative evaluations on groundwater components and possible effects of climate extreme events
Authors: Menichini Matia , Doveri Marco
Published: February 2023

The Versilia coastal plain hosts an important and strategic aquifer for water supply. Like all coastal aquifers, it is particularly vulnerable to the saltwater intrusion, which can be amplified not only by fresh water over-exploitation, but also by the effects of climate change, including the increase of extreme events that are deeply altering the hydrology of the Mediterranean regions. In order to protect this precious resource, both in quantitative and qualitative terms, an adequate knowledge of the aquifer system is necessary through the development of conceptual and mathematical hydrogeological models. Based on integrated multidisciplinary approach the conceptual hydrogeological model was defined using stratigraphic, hydrogeological and geochemical data elaboration. Subsequently, groundwater flow mathematical models were created using the ModFlow code and Groundwater Vistas like graphical interface. The models allowed to better understand this aquifer system and to identify and, where possible to quantify, the main processes and groundwater components involved. The most important feeding groundwater component, both in terms of water quantity and quality, is the fan of the Versilia River, mainly fed by the river itself in the foothill zone. Even if, in the summer season some piezometric depressions, tied to groundwater exploitation, tend to expand and move towards the coast, thus favouring the seawater intrusion process, in general, the Versilia fan component seems at present to be able to guarantee relative protection against marine ingression. However, this precarious balance could be disrupted by the extreme rainy events that frequently occur in the Apuan Alps region. The huge quantity of water that quickly flows by the river up to the sea during extreme events represents a lack of feeding respect to the aquifer, and consequently the mitigation role of the fan component towards seawater intrusion can be significantly weakened. Thanks to the water budget achieved by numerical model and considering real extreme events occurred in the Apuan-Versilian region it was possible to make considerations about possible effects of these climate regimes on the aquifer system. These extreme events as those occurred in the area in the past, and awaited more frequently in the future, represent a concrete threat for the coastal aquifer system that over next decades could suffer more and more seawater intrusion. Given the reliance of local human activities on groundwater, far-sighted actions of water management (e.g. managed aquifer recharge) are recommended for mitigating such as climate effects.
Can fiber-optic distributed sensing be used to resolve temperature turbulence values over time and space?
Authors: Vis Gijs , Hartogensis Oscar , ten Veldhuis Marie-Claire , Coenders Miriam
Published: February 2023

Turbulence is essential for land atmosphere interactions; however, it is difficult to quantify because of its statistical nature. Typically, turbulence is determined using time series data, on which Taylor’s hypothesis is applied to obtain turbulent data over a length scale. Taylor’s frozen turbulence hypothesis is an assumption in the core of turbulence research, however currently turbulence measurements are limited to either time series (e.g., sonic anemometers) or integrated spatial measurements (e.g., scintillometers). Therefore, the spatiotemporal nature of turbulence cannot be independently assessed. In this study we use fiber-optic distributed sensing (FODS) to measure turbulence over both time and space.The turbulence parameter used is the structure parameter of temperature, CT2, which quantifies the intensity of temperature fluctuations over a certain scale. The structure parameter can be determined using temperature series directly, using its definition. Alternatively, the inertial range of the turbulent temperature spectrum can be used to obtain structure parameter through the Kolmogorov -5/3 power law.A FODS experiment was conducted in the LIAISE (Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment) field campaign during 15-30 July 2021 in the north-east of Spain. A set-up was installed with a horizontal extent of 70 m, measuring at four heights between 0.40 m and 2.05 m. A thin 0.5 mm cable was used in an effort to obtain the fastest possible time response. Measurements were made at 1 Hz and 12.7 cm resolution, however the actual sampling frequency appeared to be 0.15 Hz in the temperature spectrum, likely because of the long response time of the cable.               Despite the limited 0.15 Hz sampling rate it was possible to obtain turbulence information through the use of the structure parameter of temperature. This parameter indicates the intensity of temperature fluctuations and was calculated over time, as is conventional. In a novel approach, it was also calculated over space. The spatial structure parameter obtained through the definition method was found to have the best correlation with a sonic anemometer reference, with a correlation coefficient of 0.88.The temporal structure parameter lacks the structure that is shown in the spatial method, which is likely due to the use of 30-min averaged data for horizontal wind speed from the sonic anemometer or to Taylor's frozen turbulence hypothesis not being a suitable assumption within the dimensions of this research. Determining structure parameters through the turbulent spectrum was successful for limited data points for the time seriess and is currently inconclusive for the spatial series. This work provides a first step towards using FODS in capturing turbulent information along spatial temperature series.
Uncertainty quantification in variational data assimilation with deep learning
Authors: Lafon Nicolas , Naveau Philippe , Fablet Ronan
Published: February 2023

The spatio-temporal reconstruction of a dynamical process from some observationaldata is at the core of a wide range of applications in geosciences. This is particularly true for weather forecasting, operational oceanography and climate studies. However, the re35 construction of a given dynamic and the prediction of future states must take into ac36 count the uncertainties that affect the system. Thus, the available observational measurements are only provided with a limited accuracy. Besides, the encoded physical equa38 tions that model the evolution of the system do not capture the full complexity of the real system. Finally, the numerical approximation generates a non-negligible error. For these reasons, it seems relevant to calculate a probability distribution of the state system rather than the most probable state. Using recent advances in machine learning techniques for inverse problems, we propose an algorithm that jointly learns a parametric distribution of the state, the dynamics governing the evolution of the parameters, and a solver. Experiments conducted on synthetic reference datasets, as well as on datasets describing environmental systems, validate our approach.
Groundwater conceptual model built for general public access and contribution: A case study from Australia
Authors: Ye Quanyi , Beardsell Michaela , Emmanuel Anyanwu Ifeanyi
Published: February 2023

Groundwater plays a vital role in improving the efficiency of natural water resource management and protecting and restoring water related ecosystems (SDG 6). Additionally, understanding the importance of groundwater for general public and proper management of the interactions between surface waters and their underlying aquifers is a prerequisite to maintaining their cultural and ecological value and services.

Nowadays, decisions around groundwater in Australia are out of the reach of the general people owing to a lack of awareness and technical knowledge within the field. By including people in the decision making process through an integrated groundwater surveillance platform, communities will be empowered to contribute to the resilience of water resources, safeguarding them for future generations (SDG 11).

This abstract introduces and proposes a program that is designed to raise awareness and involve the public in groundwater distribution. By using the simple concept of groundwater flow direction and interactions with surface water features, individuals can monitor and report the abnormal flow of water that may affect surface water resources. This will also enable people to raise questions about local water management plans, promoting the sustainable management of natural water resources.

The program will have a direct impact on regions suffering from the degradation of surface water features that may relate to insufficient groundwater discharge. It also serves as a preventative measure, protecting groundwater storage in regions that heavily rely on groundwater. To sum up, groundwater is a crucial link of water cycle and the sustainable management of groundwater can lead to efficient water management and improve water usage sustainability.
Estimation of NOx Emission in China by Use of Data Assimilation and Machine Learning Methods
Authors: Chen Yiang , Fung Jimmy C.H. , Lu Xingcheng
Published: February 2023

Nitrogen oxides (NOx, mainly comprising NO and NO2) is the essential precursor of secondary air pollutants, such as ozone and particulate nitrate. To better understand NOx emission levels and acquire reasonable simulation results for further analysis, a reasonable emission inventory is needed. In this study, a new method, combining the three-dimensional chemical transport model simulation, surface NO2 observations, the three-dimensional variational assimilation method, and an ensemble back propagation neural network, was proposed and applied to correct NOx emissions over China for the summers of 2015 and 2020. Compared with the simulation using prior NOx emissions, the root-mean-square error and normalized mean bias decreased by approximately 40% and 60% in the NO2 simulation using posterior NOx emissions. Compared with the emissions for 2015, the NOx emission generally reduced by an average of 5% in the simulation domain for 2020, especially in Henan and Anhui provinces, where the percentage reductions reached 24% and 19%, respectively. The proposed framework is sufficiently flexible to correct emissions in other periods and regions. It can provide policymakers and academic researchers with the latest emission information for better emission control and air pollution research.