bluuebunny/crossref_metadata_2025 huggingface dataset:
Feldspar luminescence signal of modern fluvial sediments as a proxy for erosion rates?
Authors: Guyez Anne , Bonnet Stephane , Reimann Tony , wilkinson clare , Carretier Sebastien , Norton Kevin , Wallinga Jakob
Published: February 2023

Documenting and quantifying sediment transport in natural system, especially over millennial timescale, is still challenging. Among potential new approaches, recent development has shown that luminescence signal could be used to estimate transport parameters in rivers such as virtual velocity of sediments, storage time or sediment sources (McGuire & Rhodes, 2015; Gray et al., 2018; Gray et al., 2019; Sawakuchi et al., 2018; Guyez et al., 2022).In this study, we focus on the factors controlling post-infrared feldspar luminescence signals (pIRIR) of modern fluvial sediments in upstream areas. The objective is to examine whether pIRIR equivalent dose distributions relate to landscape erosion rates and associated sediment fluxes. To test this hypothesis, we studied catchments in the Southern Alps of New Zealand (SANZ), one of the world’s most active mountain ranges, with extremely high rates of exhumation and erosion.For eight catchments of the SANZ, we compared the single-grain pIRIR equivalent dose distributions from modern fluvial sediments with catchment-wide erosion rates obtained using measurements of 10Be cosmogenic nuclide concentration in modern fluvial quartz grains. The latter approach is widely used to quantify catchment-wide erosion rates on millennial time scales.Using the cosmogenic methods, we found catchment-wide erosion rates ranging from 0.2 to 4.0 mm/yr. The rates increased along the mountain range from South-West to North-East, confirming results by Larsen et al. (2014), and may reflect a tectonic uplift gradient related to northward segmentation of the Alpine fault. In addition, erosion rates on the Western side were higher than the Eastern side, which we attribute to the climatic gradient of the SANZ, related to orographic effect.We measured single-grain pIRIR equivalent dose (De) distributions at the outlet of each catchment. We calculated (1) the fraction of grains whose luminescence signal is saturated (Bonnet et al., 2019; Guyez et al., 2022), (2) the fraction of well-bleached grains. We also characterized the De distribution using (3) the central age model (CAM; Galbraith et al., 1999) and (4) the bootstrapped minimum age model (BS-MAM; Cunningham & Wallinga, 2012). We found a relationship between those four proxies and erosion rates obtained from 10Be, as well as with suspended sediment yield (Adams, 1980; Hicks et al., 2011) and channel steepness index.Our study shows that single grain pIRIR equivalent dose distributions reflect erosion and sediment fluxes of a catchment. This new property could be further developed with the perspective to use this proxy as a new independent tool to quantify erosion and transport processes in a wide range of fluvial settings on time scales shorter than cosmogenic methods.
The importance of snowmelt in the water balance of the Toconao sub-basin, Salar de Atacama
Authors: Valdivielso Sonia , Vázquez-Suñé Enric , López Moreno Juan Ignacio , Custodio Emilio , Criollo Manjarrez Rotman , Pomeroy John W. , Hassanzadeh Ashkan
Published: February 2023

The Salar de Atacama basin is one of the best-studied saline endorheic basins in the world due to the delicate balance between extraction of lithium-rich brine from its core, tourism, and the unique ecosystems of its surrounding lagoons. However, no study to date has quantified the contribution of snowmelt compared to rainfall in supporting groundwater recharge in the basin. In this work, satellite information (Moderate Resolution Imaging Spectroradiometer, MODIS) is used to characterize the spatial and temporal dynamics of snow coverage. However, snow equivalent water is not available from remote sensing, so the Cold Regions Hydrological Model (CRHM) was used to simulate snow water equivalent, runoff, infiltration and other hydrological processes governing the water balance and groundwater recharge. CRHM makes it possible to link physical processes to hydrological processes using hydrological response units (HRU) as control volumes for water balances and as a means of discretizing the basin. HRU were defined in the Toconao sub-basin, in the eastern part of the Salar de Atacama watershed and CRHM was parameterized from regional hydrological knowledge and run for several years, forced by reanalysis data. Special attention was paid to better understand the energy balance of snow, including sublimation and wind transport ablation losses, soil infiltration processes, and the role of snowmelt in surface runoff generation and direct and indirect groundwater recharge.Satellite observations of snow cover recorded from 2000 to 2020 showed frequent snowfalls both in summer and winter. The greatest extent of snow cover occurred during winter, accounting for 60% of the annual snow-cover extent. Snow cover is generally located above 4500 m asl in summer, while in winter the snow cover is more extensive, covering a large part of the basin. The CRHM simulations show that the greatest amount of precipitation of the year falls as rain in the summer months with the drier winter dominated by snowfall. The intense summer rains produce the greatest annual fluxes of runoff and infiltration. In winter, snowmelt infiltration is approximately twice that from rainfall. Snow losses by wind transport and sublimation had little impact on the overall water balance despite the dry environment.
Social tipping points of Anthropocene acceleration dynamics in European history, from Roman times to the Little Ice Age
Authors: Izdebski Adam
Published: February 2023

The current crisis state of the planet, commonly called the Anthropocene, emerged as the result of the Great Acceleration in human consumption and environmental impact which followed the Second World War in the middle of the 20th c. There is growing evidence suggesting that similar acceleration dynamics, characterised by exponential growth in human environmental impact, occurred locally or regionally at earlier stages in human history. It is, however, difficult to identify, quantify, and confirm such cases without high-resolution, well-dated historical or paleoenvironmental data. In this presentation, I review three cases of well-documented Anthropocene-like accelerations, from Roman Anatolia, medieval Poland, and early modern Greece. In all of these cases, it was political consolidation, even if short-lived, as well as economic integration, that created the social tipping point triggering exponential acceleration of human environmental impact. All of these acceleration phases also collapsed once the underlying social dynamics was no longer present.
Interannual and seasonal water mass analysis in the Salish Sea using Lagrangian particle tracking
Authors: Beutel Becca , Allen Susan
Published: February 2023

The Salish Sea is a semi-enclosed coastal sea between Vancouver Island and the coast of British Columbia and Washington State, invaluable from both an economic and ecologic perspective. Pacific inflow to the Sea is the main contributor of many biologically important constituents. The contribution of Pacific water masses to the flow through Juan de Fuca Strait (JdF), the Salish Sea’s primary connection to the Pacific Ocean, is explored. Quantitative Lagrangian particle tracking using Ariane was applied to two numerical ocean models (CIOPS-W in the shelf region, and SalishSeaCast in the Salish Sea) matched together within JdF. Water parcels seeded near the entrance of JdF were integrated forwards and backwards in time to assess water mass path (and properties while on this path) from the shelf region and once within the Salish Sea in more detail than previously possible. During summer upwelling, intermediate flow from the north shelf and offshore dominate inflow, while during winter downwelling, intermediate flow from the south shelf and surface flow from the Columbia River plume are the dominant sources. A weaker and less consistent estuarine flow regime in the winter led to less Pacific inflow overall and a smaller percentage of said inflow reaching the Salish Sea's inner basins than in the summer. Nevertheless, it was found that winter dynamics are the main driver of interannual variability, in part due to the strongly anti-correlated behaviour and distinct properties of the two dominant winter sources. This analysis extends the knowledge on the dynamics of Pacific inflow to the Salish Sea and highlights the importance of winter inflow to the interannual variability in biogeochemical conditions in the region.
Production and radiative transfert of the OI 130.4 and 135.6 nm emissions in the Mars aurora
Authors: Soret Lauriane , Gérard Jean-Claude , Hubert Benoît , Jain Sonal
Published: February 2023

The presence of a weak oxygen emission at 130.4-nm resulting from the O 3P-3S transition was first detected in limb observations of the Martian aurora with SPICAM/Mars Express (Soret et al., 2016). It is mostly excited by direct impact of energetic electrons on ground-based O(3P) atoms, but the 130.4-nm radiation is affected by multiple scattering and absorption by CO2. In April 2021, the Emirates Mars Ultraviolet Spectrometer (EMUS) instrument (Holsclaw et al., 2021) on board the HOPE Emirates orbiter started collecting spectral images in the 110-180 nm range with a much increased sensitivity. The OI 135.6-nm emission corresponding to the 3P-5S forbidden transition has also been observed (Jain et al., 2022). In addition, EMUS is taking images of the discrete and sinuous aurora at 130.4 nm. We present Monte Carlo model simulations of the production of the O 3S and 5S excited states for different initial electron energies and discuss possible seasonal variations. We solve the radiative transfer equation for the 130.4-nm triplet and show that the I(130.4 nm/I(135.6 nm) nadir intensity ratio is expected to widely vary with the initial electron energy. These variations result from two effects:The different shapes of the two emission cross sections since the optically thick 3P-3S resonance transition is permitted while 3P-5S is forbidden
the radiation entrapment of the 130.4 nm triplet by atmospheric atomic oxygen coupled with absorption by CO2.
We also discuss the sensitivity of the 130.4-nm nadir brightness to the energy distribution of the incoming auroral electrons. ReferencesJain, S. et al. (2022), poster presented at AGU fall meeting.Holsclaw, G. et al. (2021), Space Science Reviews, 217, 1-49.Lillis, R. J. et al. (2022), Geophysical Research Letters, 49, e2022GL099820.Soret, L. et al. (2016), Icarus, 264, 398-406.
Recent Convection Decline in the Greenland Sea - insights from the Mercator Ocean System over 2008-202
Authors: abot louise
Published: February 2023

We investigated wintertime convection evolution in the past two decades over the Greenland Sea. This area is a major location regarding dense water production and supply of the lower limb of the Atlantic Meridional Overturning Circulation, a key component of the global climate.Previous studies mentioned an increase in Greenland Sea wintertime convection intensity during the 2000s in comparison with the previous decade till the mid 2010s. Here, we further document the ongoing oceanic changes within the Greenland Sea using the Mercator Ocean Physical System, an operational ocean model with data-assimilation.The model shows a large interannual variability, a later start and a decline of convection in the Greenland Sea in recent years. In particular, the depth of the annual maximum mixed layer diminished by 52 % between 2008/2014 and 2015/2020, from 1168 m to 559 m, over the convective area. There, hydrographic changes, especially a temperature increase, have led to isopycnal deepening and stratification strengthening at a larger rate in the north and east of the area (namely the Boreas Basin).Atlantic Water spreading over the Boreas Basin and the eastern part of the Greenland Basin contributes to the changes of the Greenland Sea hydrography. The model also indicates a decrease in the intensity of the gyre in accordance with the isopycnal deepening while local surface winds and fluxes do not exhibit neither significant trends nor significant interannual variations.
3D Acoustic reconstruction of lightning by two dense acoustic networks 14 km apart
Authors: Farges Thomas , Letournel Pierre , Le Pichon Alexis , Listowski Constantino
Published: February 2023

Lightning emits electromagnetic (radio and optical) or acoustic waves, commonly called thunder. In recent years, studies have shown the contribution of acoustic measurements for the 3D reconstruction of cloud-to-ground or intracloud discharges. These acoustic reconstructions are in good agreement with LMA measurements and classical lightning location systems. Recent developments allow to infer the acoustic power of the source and its variability from one flash to another as well as within a flash.In spring 2022, we set up a measurement campaign where four dense microphone arrays were deployed in the southeast of France. These arrays were composed of nine sensors distributed in a 3x3 matrix of a 20 meter square area. The signals were sampled at 100 Hz and time-stamped with the GPS reference. A thunderstorm occurred on April 23, 2022 and was observed by three of these four arrays. Comparisons with detections at a four array elements of comparable aperture highlights the contribution of denser networks in terms of detection and location capabilities. The storm of April 23 passed between two arrays 14 km apart. This campaign is a very good opportunity to demonstrate how lightning locations can be reconstructed by combining detection results at two acoustic arrays. We detail these new contributions in our presentation. 
Laboratory investigation of ion expansion produced by hypervelocity dust impacts
Authors: Nouzak Libor , Edwards Kate , Garzelli Alessandro , Munsat Tobin , Sternovsky Zoltan
Published: February 2023

In this laboratory study we present investigation of the angular distribution of expanding ions produced by hypervelocity dust impacts. Spacecraft operated by electric field antennas can characterize interplanetary and interstellar dust populations within our solar system from dust impacts. The recorded dust impact waveforms are diverse and their shape depends on the antenna mode of operation (dipole vs. monopole), impact location with respect to the antennas, spacecraft potential or dust particles properties. A unique experimental setup with delay line detector (DLD) is developed for measuring characteristics of the ion cloud expanding from the impact generated plasma. Dust particles of micron and sub-micron size are accelerated to velocities 1—80 km/s using the electrostatic dust accelerator operated at the University of Colorado. The ions produced after impact of accelerated particles on tungsten target plate are detected using the DLD that provides the position of their detection and time-of-flight. The angular distribution of ions with respect to target normal is calculated from these positions. The preliminary results indicate that the impact-generated ions expand in the form of a narrow cone and the cone angle increases with increasing dust speed.
Line radiation events: Properties, generation, and propagation
Authors: Nemec Frantisek , Santolík Ondřej , Manninen Jyrki , Hospodarsky George B. , Kurth William S.
Published: February 2023

Whistler-mode waves propagating in the Earth’s inner magnetosphere sometimes appear as a set of nearly constant frequency elements separated by a fixed frequency. Such events are typically called line radiation, and they can have two distinct origins. First, events with narrow spectral lines and the frequency spacing corresponding to the base power system frequency (50/100 or 60/120 Hz) are generated by electromagnetic radiation from electric power systems on the ground (power line harmonic radiation, PLHR). Second, waves with broader spectral lines, whose frequency spacing does not correspond to the power system frequency, are believed to be generated by plasma instabilities in the magnetosphere (magnetospheric line radiation, MLR).Frequencies of line radiation events are typically on the order of a few kHz, while their frequency spacing is on the order of a hundred Hz. Relevant spacecraft observations at larger radial distances are thus very sparse due to the typically low frequency resolution of available measurements, not sufficient to distinguish the line structure. We use high-resolution multicomponent wave measurements performed by the EMFISIS instrument on board the Van Allen Probes during the burst mode to fill this observational gap. We systematically identify the line radiation events and analyze their occurrence and properties. Detailed wave propagation analysis allows us to reveal wave propagation throughout the magnetosphere. We further show that the frequency spacing of MLR events appears to be related to an electrostatic wave observed at the corresponding frequency (≈100 Hz). Finally, conjugate observations performed by the Kannuslehto station in Finland are used to estimate the spatial extent of the events.
The change of properties of solar wind turbulence across different types of interplanetary shocks
Authors: Park Byeongseon , Pitňa Alexander , Šafránková Jana , Němeček Zdeněk , Krupařová Oksana , Krupař Vratislav
Published: February 2023

The interaction between interplanetary (IP) shocks and solar wind has been studied for the understanding of energy dissipation mechanisms and the properties of turbulence (e.g., cross helicity, residual energy, proton temperature anisotropy, magnetic compressibility, etc.) within collisionless plasmas. Compared to the study of the interaction with fast shocks, less attention has been directed to the interaction with other types of IP shocks including slow mode shocks (i.e., fast forward, fast reverse, slow forward and slow reverse). We analyze IP shocks observed by the Wind spacecraft from 1995 to 2021. Spectral indices in the ion inertial and kinetic ranges for the upstream and downstream magnetic field fluctuations are estimated by continuous wavelet transform. The changes of the plasma turbulence properties and the distributions of characteristic proton length scales are presented. We preliminarily found that spectral indices in both inertial and kinetic ranges and the distributions of characteristic proton length scales are statistically conserved across the investigated shocks. Mechanisms associated with the energy dissipation can be seen unaffected by shock. Other turbulence properties—cross helicity, residual energy and proton temperature anisotropy—evolve without a significant modification as well.
Extreme magnetopause locations and their sources
Authors: Nemecek Zdenek , Šafránková Jana , Grygorov Kostiantyn , Pi Gilbert , Aghabozorgi Nafchi Maryam , Němec František , Šimůnek Jiří
Published: February 2023

Magnetopause is a critical boundary dividing the space controlled by the Earth magnetic field from the solar wind and interplanetary magnetic field. Its position is controlled mainly by the solar wind dynamic pressure and north-south IMF component and these quantities are included in a variety of empirical magnetopause models. Comparison of observed magnetopause locations with model predictions can serve as a proof of our understanding of the interaction between solar wind and Earth magnetic field. Since the corresponding upstream conditions are usually derived from observation at L1, our knowledge on solar wind propagation and evolution on short scales are tested as well. We have collected about 40 000 of dayside magnetopause crossings observed by THEMIS, Cluster and Geotail spacecraft in course of 2007–2019 years and compared the observed magnetopause position with prediction of several empirical magnetopause models using OMNI upstream parameters. The difference between observed and predicted magnetopause radial distance, Robs - Rmod was used for quantification of the model-observation agreement. We have found that the median values of Robs – Rmod are well predicted by the tested models till Robs≈12 Re for all models but large positive deviations were found for larger magnetopause distances. A detailed analysis of such events revealed that they are connected with transient magnetopause displacements caused by magnetosheath perturbations of large amplitude and we are searching for their sources.
Accelerating urban flood modelling using a GPU-parallel non-uniform structured grid and sub-grid approach
Authors: Rong Youtong , Bates Paul , Neal Jeffrey
Published: February 2023

Remote sensing technology and the resulting high resolution geospatial data now allow for a detailed description of urban landscape, advancing the development of raster-based flood models. Previous studies have highlighted the critical role of finely resolved and accurate terrain data (5m or less) in capturing flow patterns in urban areas. However, using a uniform fine grid resolution over a rectangular domain generally results in dense grids and leads to large computational costs. The small cell size is often an overspecification for rural regions where the flow processes are changing much less rapidly. Unstructured grid models resolve this issue and trade off more complex programming and slower operation against being able to represent a given problem with fewer computational elements. An alternative solution has been recently proposed to apply the non-uniform structured grid, with fine grids covering only the regions where this detail is a necessity, for example to capture the preferential flow paths influenced by small-scale topographic features or man-made structures (river channels, buildings, roads, defences, etc.). Without this, the smoothing effect of mesh coarsening upon input topographical data in urban areas leads to a uncertain prediction of the inundation extent and the timing of inundation due to the simplified wetting process. Flow connectivity formed by the river channels and the road network, which has a strong control on urban floodplain hydraulics, is also better represented by mixing grid resolutions. Considering the large consequences in terms of economic losses caused by urban flooding, here we develop a GPU-accelerated non-uniform sub-/super-grid channel model (river channels with width below or above the fine grid resolution) for accurate and efficient urban flood modelling. Urban areas and the river channel network are forced to keep fine resolution, while a coarse representation, depending on the terrain gradient, is allowed for rural regions. This model allows the utilization of available sub-/super-grid scale bathymetric information for 1D in-channel flow representation, and a 2D model for floodplain with variable grid resolution, minimising the computational costs and below water line data requirements in the river channel. Three tests are set up to validate the model performance, and the results show that modelling the urban area with fine resolution improved the model reliability and accuracy, and reduces computational cost in rural areas where a coarse grid may be used.
Stable oxygen isotopes from the MOSAIC expedition show vertical and horizontal variability of sea-ice and river water signals in the upper Arctic Ocean during winter
Authors: Bauch Dorothea , Andersen Nils , Damm Ellen , D'Angelo Alessandra , Fang Ying-chih , Kuznetsov Ivan , Laukert Georgi , Mellat Moein , Meyer Hanno , Rabe Benjamin , Schaffer Janin , Schulz Kirstin , Tippenhauer Sandra , Vredenborg Myriel
Published: February 2023

Our aim is to better understand how local winter modification and advected signals from the Siberian Shelf affect the structure of the upper Arctic Ocean along the Transpolar Drift (TPD). Hereto we use stable oxygen isotopes of the water (δ18O) in combination with salinity to quantify river water contributions (fr) and changes due to sea-ice formation or melting (fi) in the upper ~150m of the water column during the MOSAIC drift. Furthermore, ratios of fi/fr at identical salinities can be used to distinguish waters remnant from the previous summer and those modified locally.Within the ongoing winter we observed salinification and deepening of the mixed layer (ML) due to sea-ice related brine release together with interleaving waters at the base of the ML and within the main halocline. These interleaving waters with variable sea-ice and river water signals are observed for the first time and have not been observed during summer expeditions before.The MOSAIC floe drifted in and out of the freshwater-rich part of the TPD and into the Atlantic regime throughout the winter. Despite these strong regime changes the sea-ice related brine content accumulated during the ongoing winter remained visible within the water column. Budgets derived by integration of signals over the upper 100m result in ~1 to 5 m of pure sea-water (34.92 salinity and 0.3‰ δ18O) removed from the water column for ice formation and are much higher than ice thicknesses of ~0.5 to 2 m observed for the MOSAIC floe. For further evaluation scaling factors have to be considered accounting e.g. for the different densities of ice and water as well as for the lower salinity in the halocline relative to pure sea-water. Therefore, our analysis indicates a lower limit of the advected signal relative to local winter modification within the Arctic Ocean halocline.
How to sustain the terrestrial biosphere in the Anthropocene? A thermodynamic Earth system perspective
Authors: Kleidon Axel
Published: February 2023

Many aspects of anthropogenic global change, such as land cover change, biodiversity loss, and the intensification of agricultural production, threaten the natural biosphere. Implications of these specific aspects of environmental conditions are not immediately obvious, so it is hard to obtain a bigger picture of what these changes imply and distinguish beneficial from detrimental human impacts.  Here I describe a holistic approach that provides a bigger picture and use it to understand how the terrestrial biosphere can be sustained in the presence of increased human activities.  This approach focuses on the free energy generated by photosynthesis, the energy needed to sustain both the dissipative metabolic activity of ecosystems and human activities, with the generation rate being set by the physical constraints of the environment.  One can then distinguish two kinds of human impacts on the biosphere: detrimental effects caused by enhanced human consumption of this free energy, and empowering effects that allow for more photosynthetic activity and, therefore, more dissipative activity of the biosphere.  I use examples from the terrestrial biosphere to illustrate this view and global datasets to show how this can be estimated.  I then discuss how certain aspects of modern technology can enhance the free energy generation of the terrestrial biosphere, which can then safeguard its sustenance even as human activity increasingly shapes the functioning of the Earth system.Note: Presentation is based on this manuscript (https://arxiv.org/abs/2210.09164), accepted for publication in the INSEE journal.
The Batagay megaslump in east Siberia as an archive of climate–permafrost interactions during the Middle and Late Pleistocene
Authors: Opel Thomas , Wetterich Sebastian , Meyer Hanno , Murton Julian
Published: February 2023

The Batagay megaslump (67.58 °N, 134.77 °E) is the largest known retrogressive thaw slump on Earth, and located in the Yana River Uplands near the town of Batagay in east Siberia. The slump headwall is about 55 m high and exposes ancient permafrost deposits that provide a discontinuous record of the Middle and Late Pleistocene that dates back to at least 650 ka.In this contribution, we compile cryostratigraphic observations and dating results for the permafrost exposed in the Batagay megaslump. Both provide evidence for several periods of permafrost formation and degradation. Permafrost formation and stability during Marine Isotope Stage (MIS) 16 or earlier (lower ice complex), MIS 7–6 or earlier (lower sand unit), MIS 4–2 (upper ice complex), and MIS 3–2 (upper sand unit) are reflected by the presence of deposits hosting syngenetic ice wedges and composite (i.e., ice–sand) wedges. In contrast, permafrost thaw and erosion are indicated by sharp, erosional discordances above reddish and organic-rich layers and by the accumulation of woody (forest) remains in erosional downcuts below and above the lower sand unit, and above the upper ice complex. Permafrost thaw and erosion likely took place during one or several periods between MIS 16 and MIS 7–6 as well as during MIS 5 and the late Pleistocene–Holocene transition.To gain seasonal-scale climate signals, we analyzed the stable isotope composition of ground ice (ice and composite wedges and pore ice) from all four main stratigraphic units reflecting permafrost aggradation exposed in the Batagay megaslump. Ice and composite wedges contain winter climate signals. Their distinctly depleted δ18O values reflect the extreme continentality of the region with large seasonal temperature differences. Pore ice is mostly characterized by less depleted δ18O values and rather reflects summer to annual climate signals subject to post-depositional isotopic fractionation.To draw large-scale conclusions on climate–permafrost interactions we compare our data to independent climate and permafrost reconstructions from terrestrial (cave deposits, lake sediment cores, and permafrost deposits) and marine sediment cores across the Arctic.
Recent European drying and its link to prevailing large-scale atmospheric patterns
Authors: Bakke Sigrid Jørgensen , Ionita Monica , Tallaksen Lena Merete
Published: February 2023

The European continent has been struck by several extreme droughts over the last decades, associated with wide ranging societal, environmental and economic impacts. Changes in large-scale atmospheric circulation are vital for understanding the spatial patterns of changes in seasonal meteorological drought. The study presented herein is based on Bakke et al. (in review) and we begin by demonstrating the coherent pattern in the development of extreme meteorological drought and high-pressure systems during the extreme 2018 and 2022 drought events in Europe. Next, we investigate the relation between changes in large-scale atmospheric patterns and meteorological drought, as indicated by the geopotential height at 500mb (Z500) and the Standardised Precipitation-Evapotranspiration Index (SPEI), respectively. Calculations are done separately for four climate regions (North, West, Central-East and Mediterranean) over the growing season (March-September). Overall, the results show a low sensitivity to the Z500 data sets used (NCEP, ERA5, ERA20C and 20C), and the SPEI data sets (CRU and EOBS) at the regional level. We find coherent spatial patterns in 1979–2021 trends in seasonal and monthly Z500 and SPEI, with hot spots of significant changes towards higher pressure (increasing Z500) and drier conditions (decreasing SPEI) over West in spring and Central-East in summer. Strong correlations (at 1% significance level) between the variables are found for all regions throughout the growing season. A strong relation between high-pressure systems and meteorological drought is confirmed by a high degree of co-occurring regional anomalies since the beginning of the 20th century. The strongest links are detected in West, and the weakest links in North. Finally, we investigate projected Z500 according to a low-end (SSP126) and a high-end (SSP585) emission scenario. According to the projected changes, anomalously high-pressure systems will be the new normal regardless of scenario, and well exceeding the 2018 and 2022 levels in the case of the high-end emission scenario. The ability of the model ensemble to represent the spatial heterogeneity in historical Z500 variability and trends is limited. Thus, projected changes in large-scale circulation are highly uncertain. Consequently, due to the strong link between Z500 and SPEI, high uncertainties are associated with projected changes in drying trends and meteorological drought across Europe.Bakke, S.J., Ionita, M. and Tallaksen, L.M.: Recent European drying and its link to prevailing large-scale atmospheric patterns. npj Climate and Atmospheric Science (in review). https://doi.org/10.21203/rs.3.rs-2397739/v
Improving SAR Altimeter processing over the coastal zone and inland waters- the ESA HYDROCOASTAL project
Authors: Cotton David
Published: February 2023

The objectives of the HYDROCOASTAL project, funded by the European Space Agency under the EO Science for Society programme, are to enhance our understanding of interactions between the inland water and coastal zone, between the coastal zone and the open ocean, and the small scale processes that govern these interactions. The project also aims to improve our capability to characterize the variation at different time scales of inland water storage, exchanges with the ocean and the impact on regional sea-level changes To achieve these aims, the HYDROCOASTAL project team has developed and implemented new SAR altimeter processing algorithms for the coastal zone and inland waters, and with these processed Sentinel 3A, 3B and Cryosat-2 data to generate  to generate an initial 2-year Test Data Set for selected regions. The performance of these new algorithms has been evaluated, by statistical analyses and comparison against in situ data. From this analysis, the best performing algorithms have been identified and a processing scheme implemented to generate a global scale coastal zone and inland water altimeter data set. A series of case studies are now assessing these products in terms of their scientific impacts.  All the produced data sets will be available on request to external researchers, and full descriptions of the processing algorithms are available via the project web-site The presentation will provide an overview of the HYDROCOASTAL project, describe the different SAR altimeter processing algorithms that have been implemented and evaluated in the first phase of the project, and present results from the evaluation of the initial test data set. It will also present early results from  impact studies.
A large-scale flood modeling using geometry-adaptive physics-informed neural solver and Earth observation data
Authors: Xu Qingsong , Shi Yilei , Bamber Jonathan , Ouyang Chaojun , Zhu Xiao Xiang
Published: February 2023

Large-scale hydrodynamic models generally rely on fixed-resolution spatial grids and model parameters as well as incurring a high computational cost. This limits their ability to accurately forecast flood crests and issue time-critical hazard warnings. In this work, we build a fast, stable, accurate, resolution-invariant, and geometry-adaptative flood modeling and forecasting framework that can perform at scales from continental to global. We achieve this by combining continuous flow modeling of a geometry-adaptive physics-informed neural solver (GeoPINS) with the authenticity of Earth observation data. Specifically, the GeoPINS is proposed based on the advantages of no training data in physics-informed neural networks (PINNs), as well as possessing a fast, accurate, and resolution-invariant architecture through the implementation of Fourier neural operators (FNO). In particular, to adapt to complex and irregular geometries that exist in rivers, we reformulate PINNs in a geometry-adaptive space by taking full advantage of coordinate transformations and the efficiency of numerical methods in solving the spatial gradient. We validate our GeoPINS on popular partial differential equations on both regular and irregular domains, demonstrating fast, stable, and accurate performance, as well as resolution-invariant, geometry-adaptive properties. Next, due to a lack of large-scale ground truth data, time-series flood records are generated using freely available Sentinel-1 data and a SAR-based flood mapping algorithm. These flood records are used as boundary conditions and flood inundation extent verification of the proposed hydrodynamic model. Finally, we compare our GeoPINS results with a 30 m resolution, SAR-based flood record, and measured discharge from gauging stations, obtaining good agreement among the three. The experimental results for the Pakistan flood in 2022 indicate that the proposed method can maintain high-precision large-scale flood dynamics solutions at different resolutions and flood hazards can be forecast in real-time with the aid of reliable precipitation data.
Physics of the Eddy Memory Kernel of a Baroclinic Midlatitude Atmosphere
Authors: Vanderborght Elian , Demeayer Jonathan , Dijkstra Henk , Manucharyan Georgy , Moon Woosok
Published: February 2023

In recent theory trying to explain the origin of low-frequency atmospheric variability, the concept of eddy-memory has been suggested. In this view, the effect of synoptic scale heat fluxes on the mean flow depends on the history of the mean meridional temperature gradient. Mathematically, this involves a convolution of an integral kernel with the mean meridional temperature gradient over past times. In atmospheric studies, it has been proposed that the shape of this integral kernel is linked to the baroclinic wave life cycle. However, this hypothesis has yet to be supported by numerical and observational evidence. In this study we use a low-order two layer quasi-geostrophic atmospheric model (Demaeyer et al., 2020). By perturbing the model with a known forcing, linear response theory can be used to estimate the shape of the integral kernel. Using this methodology, we find an integral kernel that resembles the shape of an exponentially decaying oscillation, different from the simple exponentially decaying integral kernel assumed in most previous studies. By computing the energies and performing a sensitivity analysis, we link the shape of the integral kernel to atmospheric dynamical processes.References:J. Demaeyer, L. De Cruz, and S. Vannitsem. qgs: A flexible python framework of reduced-order multiscale climatemodels. Journal of Open Source Software, 5(56):2597, 2020.
Atmospheric and ionospheric disturbances in Europe induced by Hunga eruption on 15 January 2022
Authors: Chum Jaroslav , Šindelárová Tereza , Koucká Knížová Petra , Podolská Kateřina , Rusz Jan , Danielides Michael , Schmidt Carsten
Published: February 2023

The massive explosive eruption of the Hunga Tonga volcano on 15 January generated atmospheric waves that were comparable with those generated by the Krakatoa 1883 eruption. The waves were recorded around the globe and affected also the ionosphere. We focus on observation of atmospheric waves in the troposphere and ionosphere in Europe. The tropospheric waves are studied using a large aperture array of microbarometers and the ionospheric disturbances are detected using continuous Doppler sounding. It is shown that long-period infrasound (periods longer than ~50 s) is observed simultaneously in the troposphere and ionosphere about an hour after the arrival of the first pressure pulse (Lamb wave) in the troposphere. Data analysis confirms propagation approximately along the shorter great circle path both for the infrasound and the Lamb wave. It is suggested that the infrasound propagated into the ionosphere probably due to imperfect refraction in the lower thermosphere. The observation of infrasound in the ionosphere at such large distances from the source (over 16 000 km) is rare and differs from ionospheric infrasound detected at large distances from the epicenters of strong earthquakes, because in the latter case the infrasound is generated locally by seismic waves. An unusually large traveling ionospheric disturbance (TID) observed in Europe and associated with the pressure wave from the Hunga Tonga eruption is also discussed. In addition, a probable observation of wave in the mesopause region approximately 25 min after the arrival of pressure pulse in the troposphere using a 23.4 kHz signal from a transmitter 557 km away is shown.
Mutual relationships between evapotranspiration and soil water storage in a small agricultural catchment and their consistency from a statistical viewpoint
Authors: Li Tailin , Schiavo Massimiliano , Zumr David
Published: February 2023

Accurate measurements and estimates of evapotranspiration (ET) and soil moisture are essential for efficient crop management and understanding of hydrological processes in agricultural catchments. In this study, we used satellite imagery for a small catchment (Nučice, Czech Republic) to retrieve vegetative indices (VIs, including NDVI, SAVI and EVI), hence to analyse their spatial and temporal variability. Furthermore, we investigated the relationship between vegetative indices (VIs), measured evapotranspiration (ET), and soil water storage (SWS). Also, for each variable, we aggregated weekly data at the seasonal temporal resolution, being able to study the trends of each variable’s statistical moments. Moreover, we employed the Normalized Nash-Sutcliffe Efficiency (NNSE) index to study the error and the bias between normalized variables within the same seasonality. We found linear relationships between VIs, ET, and SWS when they exceeded a certain threshold. We were able to estimate the ET by exploiting its linear relationships with VIs and SWS, thus bridging the measurement gap. Our results suggest ET prediction based on VIs can be used during the growing season but may give inaccurate results after harvest (when VIs have low values). SWS can provide a reasonable estimate of the ET when no vegetation is present. Furthermore, the good correspondence between the seasonal NNSE indices and the trends of statistical moments of ET, VIs, and SWS suggest that subsurface processes might be inferred from seasonal vegetation cover. Therefore, this allows us to anticipate the likelihood of seasonal correlations across surrogate variables, further studying the spatial variations of SWS throughout the catchment in connection to ET and VIs.This research has been supported by the Grant Agency of the Czech Technical University in Prague, Grant No. SGS20/156/OHK1/3T/11 and TUdi project, EU Horizon 2020 Grant Agreement No 101000224. 
Near-real-time global gridded daily CO2 emissions
Authors: Dou Xinyu , Liu Zhu , Ciais Philippe , Hong Jinpyo , Chevallier Frédéric , Wang Yilong , Yan Feifan , Davis Steven J. , Crippa Monica , Janssens-Maenhout Greet , Guizzardi Diego , Solazzo Efisio , Song Xuanren , Huo Da , Ke Piyu , Wang Hengqi , Deng Zhu
Published: February 2023

Timely, fine-grained gridded carbon emission datasets are particularly important for global climate change research. Often, fine-grained datasets are challenging to visualize over the globe, and clear visualization tools are also needed. Therefore, we present a near-real-time global gridded daily CO2 emissions dataset (GRACED). GRACED provides gridded CO2 emissions at a 0.1° × 0.1° spatial resolution and 1-day temporal resolution from cement production and fossil fuel combustion over seven sectors, including power, industry, residential consumption, ground transportation, domestic aviation, international aviation, and international shipping. GRACED is prepared from the near-real-time daily national CO2 emissions estimates (Carbon Monitor), multi-source spatial activity data and satellite NO2 data for time variations of those spatial activity data. Here, we examined the spatial patterns of sectoral CO2 emission changes from January 1, 2019, to December 31, 2021. In 2021, most regions showed rapid rebounds in carbon emissions compared with 2020, reflecting the continuing challenges to accelerate climate mitigation in the post-COVID era. GRACED provides the most timely and more refined overview than any other previously published datasets, which enables more accurate and timely identification of when and where fossil CO2 emissions have rebounded and decreased as the world recovers from COVID-19 and witnesses contrasted efforts to decarbonize energy systems. Uncertainty analysis of GRACED gives a grid-level two-sigma uncertainty of value of ±19.9%, indicating the reliability of GRACED was not sacrificed for the sake of higher spatiotemporal resolution that GRACED provides. In addition, we also examined the distribution of emission in a grid-wise perspective for major emission datasets, and compared it with GRACED. The similarity in emission distribution was observed in GRACED and other datasets. One of the advantages of our dataset is that it provides worldwide near-real-time monitoring of CO2 emissions with different fine spatial scales at the sub-national level, such as cities, thus enhancing our comprehension of spatial and temporal changes in CO2 emissions and anthropogenic activities. With the continued extension of GRACED time series, we present crucial daily-level input to analyze CO2 emission changes in the post-COVID era, which will ultimately facilitate and aid in designing more localized and adaptive management policies for the purpose of climate change mitigation in the post-COVID era.
Waterbody Extraction from Small and Medium-Sized Streams Using Sentinel-1 Images Based on Shortest Plane Distance
Authors: Kim Soohyun , Kim Dongkyun
Published: February 2023

In this study, SAR (Synthetic Aperture Radar) images are used to validate a method for extracting the waterbody from small and medium-sized streams based on the shortest plane distance (DST). The research area is the Hantangang River and Jungnangcheon in the Hangang River Basin of South Korea. To validate the water body extraction method, SAR satellite image data (Sentinel-1) and high-resolution optical satellite PlanetScope are employed concurrently. After preprocessing, the brightness distribution of the Sentinel-1 photos is equalized using histogram matching. To achieve an efficient stream extraction, a weight is applied that is the DST from the stream centerline. The optimal parameter value is obtained using the k-means method after combining this weight value with Sentinel-1's VH and VV polarizations. Depending on the resolution limit, this value allows the waterbody to be extracted with maximum accuracy from Sentinel-1 images. The waterbody extraction can be calculated using an elliptic equation based on the correlation between the VV, VH, and DST. Results show that the average accuracy is 0.45-0.75, and the average Kappa coefficient is 0.60-0.85. This study demonstrates that the DST can be used to estimate the area of a waterbody. Furthermore, the proposed method extracts the waterbody more easily and quickly than the existing method.This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. NRF-2021R1A2C2003471).
Late complex tensile fracturing interacts with topography at Cumbre Vieja, La Palma
Authors: Walter Thomas R. , Zorn Edgar , Gonzalez Pablo , Sansosti Eugenio , Munoz Valeria , Shevchenko Alina , Plank Simon , Reale Diego , Richter Nicole
Published: February 2023

Volcanic eruptions are often preceded by episodes of inflation and emplacement of magma along tensile fractures. Here we study the 2021 Cumbre Vieja eruption on La Palma, Canary Islands, and present evidence for tensile fractures dissecting the new cone during the terminal stage of the eruption. We use synthetic aperture radar (SAR) observations, together with drone images and time-lapse camera data, to determine the timing, scale and complexities associated with the fracturing event, which is diverging at a topographic ridge. By comparing the field dataset with analogue models, we further explore the details of lens-shaped fractures that are characteristic for faults diverging at topographic highs and converging at topographic lows. The observations made at Cumbre Vieja and in our models are transferrable to other volcanoes and add further evidence that topography is substantially affecting the geometry and complexity of fractures and magma pathways, and the locations of eruptions.