bluuebunny/crossref_metadata_2025 huggingface dataset:
Fast Growing Forests (FGF) to offset Greenhouse Gas (GHG) Emissions
Authors: Jaiswal Deepak , Surendran Sruthi , Lopus Merlin , Kushwaha Amit , K Chandrabose Akhila , Geveena Anna , Shaji P Saranga , Nair Sethulakshmi , Sreejith Kalpuzha Ashtamoorthy
Published: February 2023

Nature-based solutions (Nbs) are seen as an effective way to mitigate climate change and stabilize the climate of the earth. Here, we report ground measurements of a newly established forest site on the campus of IIT Palakkad, Kerala India (lat = 10.809, lon =76.746). The site (approximately 1600 meter2 ) was previously dominated by fountain grass, which is locally considered to be an invasive species. After land preparation, a new forest utilizing approximately 20 native species of trees was planted following Miyawaki's methodology. Direct measurements of tree diameter at the breast height (tbh) were made to estimate total standing biomass using species specific allometric equations. The standing biomass after two years is estimated to be 3261 kg (5967 kg CO2) over the entire forest area. The total carbon sequestered during the first two years of this forest’s life is sufficient to neutralize carbon emission by a gasoline car driven for a distance of 48909  km or carbon emission by a car running on 100E fuel over a distance of 349355 km. Our work demonstrates that the carbon sequestration rate (18 tons CO2 ha-1 yr-1) by the forest established using the Miyawaki method at our study site is comparable to some of the most productive forests reported in the available literature. Further, our analysis demonstrates that NbS can be made more efficient if spatial land use planning can be optimized to make room for sustainable biomass production for energy and conservation purposes.
Improving the statistical correlations between low seismic events and CO2 variations subtracting the rain contribution
Authors: Pierotti Lisa , Fidani Cristiano , Facca Gianluca , Gherardi Fabrizio
Published: February 2023

A correlation between low seismic activity and CO2 measurements variations was observed at the Gallicano thermomineral spring, Tuscany, Italy, where an automatic monitoring multiparametric geochemical station is operative since 2003 (Pierotti et al., 2015). The above-mentioned correlation reported a time delay of about 2 days of small earthquakes with respect to CO2 anomalies. Starting from this correlation a conditional probability of earthquake occurrence given the CO2 anomaly detection was calculated, with a probability gain near 4 (Pierotti et al., 2022).  A statistical correlation was also calculated between rain events and CO2 anomalies which was observed for rain vents ahead CO2 anomalies of one days. This permitted to distinguish CO2 anomalies due to meteorological versus tectonic activities.  Following this distinction, and subtracting the rain contribution to the CO2 variations, a new correlation was observed between small earthquakes and CO2 anomalies which confirmed the past results whit a better performance. The new correlation peak is better defined and concentrated in the time lag of 2 days. The p-values of both earthquake and rain to CO2 correlations were calculated. The correspondent probability gain in an earthquake forecasting experiment, taking into account the rain events, increased from less than 4 to 4.5.       Fidani, C. (2021). West Pacific Earthquake Forecasting Using NOAA Electron Bursts With Independent L-Shells and Ground-Based Magnetic Correlations. Front. Earth Sci. 9:673105.Pierotti, L., Botti, F., D’Intinosante, V., Facca, G., Gherardi, F. (2015). Anomalous CO2 content in the Gallicano thermo-mineral spring (Serchio Valley, Italy) before the 21 June 2013, Alpi Apuane earthquake (M= 5.2). Physics and Chemistry of the Earth, Parts A/B/C, 85, 131-140.Pierotti, L., Fidani C., Facca, G., Gherardi, F. (2022). Local earthquake conditional probability based on long term CO2 measurements. In 40st GNGTS National Conference, Trieste, 27 - 29 June 2022.
Unlocking the physiological and climatic hydrogen isotope signal in tree rings and leaf n-alkanes in a boreal forest
Authors: Angove Charlotte , Lehmann Marco , Saurer Matthias , Wiesenberg Guido , Young Giles , Rinne-Garmston Katja
Published: February 2023

It is essential to comprehensively understand past climate and tree response to climate change because trees are directly exposed to rapid, intensifying, and widespread climate change. Both tree rings and leaf n-alkanes are long-term biomarkers which can help to better understand past climate and/or tree response to climate change. For example, interpreting carbon and oxygen stable isotopes in tree rings contribute to understanding past climate and tree response to climate change. However, greater insight could be achieved if hydrogen stable isotopes can also be clearly interpreted. To clearly interpret hydrogen isotopes in tree rings it is necessary to discover which aspects of climatic variability and tree physiology are most clearly expressed by hydrogen isotopes in tree rings. Additionally, the climatic signal of hydrogen stable isotopes in leaf n-alkanes can be deposited to soil and sediments from plants, and their climatic soil record can date back to thousands to millions of years ago. However, there are still aspects of plant physiology that have not been accounted for in leaf n-alkane hydrogen isotope interpretation, which limits the reliability of their interpretation. While data from tree rings and leaf n-alkanes are rarely combined, both tree rings and leaf n-alkanes contain a hydrogen isotope signal that originates from a hydrogen isotope signal in source water that is changed by physiological processes and interacting climatic factors during their biosynthesis. This project aims to improve our understanding of the physiological and climatic signals contained in the hydrogen isotope signal in both tree rings and leaf n-alkanes. It helps increase the useability of the hydrogen isotope signal in tree rings and helps improve the reliability of interpreting climatic signals from leaf n-alkanes. It uses a unique dataset from a field survey with samples collected multiple times during a growing season, with high temporal resolution, at one to two boreal forests in southern Finland (e.g., Leppä et al. 2022; Tang et al., 2022). This dataset is rich with information from multiple sources, such as multiple element isotope concentrations in various plant tissues and water isotope pools, as well as leaf gas exchange data, meteorological data, and eddy covariance data. The hydrogen isotope signal is traced from the climatic signal in source water, to the physiological and climatic signal in leaf water, sugars and starches and leaf n-alkanes, then from the same leaf water, sugars, and starches to bark and stem phloem sugars and starches, to high-resolution intra-annual tree ring α-cellulose. This presentation gives the project outline and some main findings.Leppä et al. (2022) doi:10.1111/nph.18227Tang et al. (2022) doi: 10.1093/treephys/tpac079
Role of syn-orogenic sedimentation in the evolution of a foreland fold and thrust belt: an example from the Jaca basin, South Pyrenean Zone
Authors: Menzer Lionel , Bonnel Cédric , Hoareau Guilhem , Aubourg Charles , Callot Jean-Paul
Published: February 2023

Foreland fold and thrust belts (FFTB) are the locus of strong interactions between tectonics and sedimentation during both mountain building then dismantling processes. Especially, the nature and rheology of decollement layers within the basin pre and/or syn-orogenic sequence are susceptible to influence the kinematic evolution and geometry of FFTBs as well as the growth of orogenic wedges.In the South Pyrenean Zone, the Jaca basin forms the main pro-foreland basin filled by marine to continental siliciclastic sediments during Eocene and Lower Oligocene times. From Bartonian until Rupelian at least, several alluvial fans were successively deposited from east to west along its northern margin in the footwall of emergent thrusts, where they were accompanied by the syn-sedimentary growth of shale-cored anticlines downstream.Field surveys and “bed-to-bed” mapping of syn-orogenic formations using high-resolution DEMs were used with re-interpreted published seismic lines to build two cross-sections that highlight the structural style and evolution of the Gavarnie-Jaca FFTB. This illustrates the tectono-sedimentary evolution of a transitional, shallow-marine to alluvial foreland margin.The Eocene-Oligocene syn-orogenic deposits are folded as a wide synclinorium that is thrusted southward over the Ebro foreland along to the Triassic detachment level. In the northern limb, the late Eocene Orosia-Cancias conglomerates exhibit a short-wavelength and small-scale fold detached within the late Middle Eocene shallow marine marls. Beneath this decoupling level, the Lower and Middle Eocene turbidites form a gently foreland ward-dipping imbricate composed of several small-scales thrust-sheets detached at the base of Upper Cretaceous. During end-Bartonian and early Priabonian, the deposition of the Orosia alluvial fan was coeval with the early growth of the Basa anticline downstream. From Priabonian, the anticline was subsequently welded and forward-tilted coevally with the development of the turbidite imbricate beneath, in response to the Gavarnie thrust-sheet emplacement. At this time, the second Cancias conglomerate unit was deposited as a large fluvial fan that progressively filled the foreland basin northern margin.The tectono-sedimentary evolution of the north-eastern Jaca foreland margin illustrate the interactions between the regional convergence, syn-orogenic shales tectonics and alluvial sedimentation within a foreland fold and thrust belt. The South Pyrenean foreland documents a first example of a gliding alluvial fan on gravity-driven mobile shales in a convergent margin setting.
Exploring hemispheric tectonics on tidally locked super-Earths
Authors: Meier Tobias G. , Bower Dan J. , Lichtenberg Tim , Tackley Paul J. , Hammond Mark , Demory Brice-Olivier
Published: February 2023

Many super-Earths are very close-in to their host star and are therefore likely to be tidally locked. Tidally locked super-Earths experience intense solar heating on their permanent dayside, whereas the nightside surface can reach extremely cold temperatures. For the case of super-Earth LHS 3844b, a bare-rock super-Earth with a radius around 1.3 Earth radii, we have shown that this strong contrast between the dayside and nightside surface temperature can lead to a so-called hemispheric tectonic regime. Such a regime is characterised by a strong downwelling on one hemisphere and upwellings that rise on the other side. We further define hemispheric tectonics as a special case of degree-1 convection (one upwelling and one downwelling), where the downwelling gets pinned to either the dayside or nightside and upwellings are preferentially on the other hemisphere.  Here, we focus on super-Earth GJ 486b, which has also a radius around 1.3 Earth radii, but for which it is unknown whether it was able to retain an atmosphere. We investigate how different surface temperature contrasts affects the likelihood of hemispheric tectonics.  For this, we run 2D geodynamic simulations of the interior mantle flow using the mantle convection code StagYY. The models are fully compressible with an Arrhenius-type viscosity law where the mantle is mostly composed of perovskite and post-perovskite. The lithospheric strength is modelled through a plastic yielding criterion and the models are basally heated. We use general circulation models (GCMs) of potential atmospheres to constrain the surface temperature assuming different efficiencies of atmospheric heat circulation. We find that degree-1 convection is a consequence of the strong lithosphere, while hemispheric tectonics is favoured for strong surface temperature contrasts between the dayside and nightside, and higher surface temperatures. Our results show that hemispheric tectonics or degree-1 convection could operate on super-Earth GJ 486b (or other tidally locked super-Earths), even if the surface temperature contrast between the dayside and nightside is not as strong as for LHS 3844b. Upwellings that rise preferentially on one hemisphere could lead to generation of melt and subsequent outgassing of volatiles on that side. Imprints of such outgassing on the atmospheric composition could possibly be probed by current and future observations such as JWST, ARIEL, or the ELT. 
Sensitivity of tropical Atlantic subsurface currents to different model parameter choices in ICON-O
Authors: Bastin Swantje , Putrasahan Dian , Jungclaus Johann
Published: February 2023

The tropical oceans are home to some of the strongest subsurface current systems of the world. Among these are the Equatorial Undercurrent (EUC) which flows eastward below the thermocline, and the Equatorial Intermediate Current System (EICS) consisting of latitudinally alternating zonal jets between 15S and 15N. Ocean and climate models consistently struggle in correctly representing these subsurface currents, but especially the EUC is quite important for tropical Atlantic climate, e.g. the evolution of the Atlantic cold tongue and the associated Atlantic Niño. We use the ocean component of the ICON model to test how the representation of the Atlantic subsurface current systems reacts to different model parameter choices. In general, the EUC is too weak in our ICON configuration. We can show that the EUC is stronger, i.e. better represented with the TKE vertical mixing scheme than with the KPP scheme. Using the TKE scheme, different parameters are tested and it can be shown that the EUC reacts sensitively to the value of the important tuning parameter c_k, being stronger when c_k is smaller. We also test the sensitivity of the EUC strength in the model to the formulation of the Prandtl number in the TKE mixing scheme, which also includes a changeable constant. Apart from changes in the vertical mixing scheme, we also look at the effect of the vertical resolution of the near-surface ocean. We compare a vertical level thickness of 2m in the upper 20m to 10m in the upper 20m, with the same level distribution below 20m depth for both configurations. We can show that for the thinner surface levels, the EUC is much weaker than for the thicker levels. Intriguingly, also the EICS react to the change in near-surface vertical resolution despite being located at much larger depths. The EICS is, like the EUC, generally too weak in ICON, but becomes stronger when the near-surface levels are thinner.
Comparison and Future Projection for Rainfall Quantile based on CMIP6 and CMIP5: Focusing on the Seomjingang River Basin
Authors: Kim Sunghun , Kim Heechul , Shin Ju-Young , Heo Jun-Haeng
Published: February 2023

This study attempts to estimate the extreme rainfall quantiles using the Intergovernmental Panel on Climate Change (IPCC)'s latest Coupled Model Intercomparison Project Phase 6 (CMIP6) and Coupled Model Intercomparison Project Phase 5 (CMIP5) models. In general, applied climate change research is carried out using numerical simulation data from various general climate models (GCMs). In this study, the precipitation data were obtained from CMIP5 and CMIP6 webpages of the World Climate Research Programme (WCRP). For the same GCM models, the Representative Concentration Pathways (RCP) scenarios (RCP4.5, RCP8.5) and Shared Socioeconomic Pathways (SSP) scenarios (SSP2-4.5, SSP5-8.5) were compared. The simple quantile mapping (SQM) method was applied for bias correction, and the at-site frequency analysis was performed for rainfall quantile estimation. In addition, the L-moments approach was applied to estimate the parameters, and the generalized extreme value (GEV) distribution was employed as the appropriate probability distribution. As a result, rainfall quantiles were estimated for each same GCM, and the change effects of different scenarios in the study area were quantitatively compared.
Monitoring the 2020 storm Gloria in the Ebro Delta (Western Mediterranean) using Earth Observation data
Authors: Roca Mora Mar , Navarro Almendros Gabriel , Bonnet Dunbar Martha , Caballero de Frutos Isabel
Published: February 2023

Coastal hazards and extreme events are increasing in frequency and severity due to climate change, making the littoral zone even more vulnerable and requiring continuous monitoring for its optimized management. The Ebro Delta ecosystem, located in the NW Mediterranean, was subject to storm “Gloria” in the winter of 2020, the most severe coastal storm registered in the area in decades. In this study, Landsat-8 and Sentinel-2 satellites were used to monitor flooding impact and water quality status, including chlorophyll-a, suspended particulate matter, and turbidity in different time slots to evaluate pre-, syn-, and post-storm scenarios. Image processing was carried out using the ACOLITE software and the on-the-cloud Google Earth Engine platform for water quality and flood mapping, respectively, showing a consistent performance for both satellites. This cost-effective methodology allowed us to characterize the main water quality variation in the coastal environment during the storm, as well as to detect a higher flooding impact (7311 ha) compared to the one registered 3 days later by the Copernicus Emergency Service (3672 ha) regarding the same area. Moreover, the time series revealed how the detrimental impact on water quality and turbidity conditions was restored two weeks after the extreme weather event, and no phytoplankton blooms appeared during the study period neither in the Ebro Delta nor in adjacent regions. These results, obtained within the EuroSea project (H2020 grant agreement No 862626), demonstrate that the used workflow is suitable for monitoring extreme coastal events in the Ebro Delta using open satellite imagery at 10-30 m spatial resolution and four-day revisit time, thus providing valuable information for early-warning to facilitate timely assistance and hazard impact evaluation. The integration of high-resolution remote sensing tools into ecological disaster management can significantly improve current monitoring strategies, supporting decision-makers from the local to national level especially in prevention, adaptation measures, and damage compensation.Keywords: Remote Sensing; Water Quality; Flooding; Coastal Management; Sentinel-2; Landsat-8.
Formation of secondary organic aerosol from sitka spruce emissions
Authors: Furnell Hayley , Kammer Julien , Wingler Astrid , Kilcawley Kieran , Mannion David , Wenger John
Published: February 2023

Biogenic volatile organic compounds (BVOCs) emitted from a wide range of trees and plants undergo oxidation reactions in the atmosphere to produce secondary organic aerosol (SOA), which has direct and indirect effects on climate, and is accountable for a large proportion of climate uncertainties. The composition and yield of SOA is determined by the precursor BVOCs, which depends on the emission profile of the plant. In Ireland forestry is dominated by Sitka spruce (Picea Sitchensis), the emissions of which are not well characterised. The goal of this study is to identify the BVOC emissions from Sitka spruce, and to assess their SOA formation potential.To characterise the emission profile of Sitka spruce, 4-year old trees were housed in a plant growth chamber under controlled environmental conditions and the emissions monitored on-line with a time-of-flight chemical ionisation mass spectrometer (ToF-CIMS), and off-line with thermal desorption gas chromatography mass spectrometry. The atmospheric reactions of the VOCs emitted by the Sitka spruce were investigated by oxidising them with hydroxyl (OH) radicals in an atmospheric simulation chamber. BVOC oxidation and gas-phase product formation was monitored by ToF-CIMS. A scanning mobility particle sizer (SMPS) was used to track particle formation and growth, and the SOA composition was determined with the use of a filter inlet for gas and aerosols (FIGAERO) fitted to the ToF-CIMS.Over 60 different BVOCs were identified in the Sitka spruce emissions, with oxygenated species accounting for over 50% of them. The most abundant compound identified was piperitone, C10H16O an oxygenated monoterpene. Other compounds prevalent in the emissions included isoprene and monoterpenes, such as myrcene and β-phellandrene. During oxidation experiments the decay of the Sitka spruce emissions was observed with the ToF-CIMS in C6H6+ mode, while the formation of oxidised gas products was observed in I- mode. The most prevalent gas-phase product was C5H6O3. Analysis of the gas-phase oxidation products indicated that the oxidation of multiple BVOCs led to their formation. Particle formation and growth commenced quickly after the OH reaction was initiated. The composition of the SOA showed C6H8O6 as the dominant species, but the majority of the products had formulas in the range #C7 – 15 and #O5 - 8. Analysis of both gas and particle phase chemistry has been performed to determine the SOA formation potential of Sitka spruce BVOC emissions. 
Changes in air-sea fluxes over the North Atlantic during 1950-2019 as derived from ERA5 data
Authors: Mayer Johannes , Haimberger Leopold , Mayer Michael
Published: February 2023

Air-sea heat fluxes play a key role for many processes in the North Atlantic Ocean, such as the lateral transport of energy or the formation of storm tracks. Thus, an accurate estimation of air-sea heat flux trends is pivotal and helps to understand implications of climate change. To do so, reanalysis products are attractive candidates due to their excellent spatial coverage over multiple decades. However, trend estimations based on reanalysis data are challenging as changes in the observing system can introduce temporal discontinuities.In this study, we explore the reliability and temporal stability of net air-sea heat flux trends from ERA5 forecasts in the North Atlantic basin over the period 1950-2019.  The assessment is complemented with an indirect estimate of the net surface flux derived from the atmospheric energy budget. Causes of trends in latent and sensible heat fluxes are identified based on monthly analyzed state quantities from ERA5, such as wind speed, moisture, and temperature. Additionally, the impact of the North Atlantic Oscillation (NAO) and Atlantic Multi-decadal Oscillation (AMO) as well as analysis increments, as introduced by the ERA5 data assimilation, is investigated.  Our results show a robust increase of latent heat fluxes in the tropical North Atlantic over the past seven decades, which is likely caused by the intensification of the Hadley cell favouring subsidence and advection of drier air masses. In the Norwegian Sea, positive net air-sea heat flux trends (increased ocean heat uptake) are largely dominated by changes in sensible heat fluxes, which are driven by a trend towards more southerly winds and the advection of warmer air. In the Gulf Stream region, the AMO likely drives the multi-decadal variability of net air-sea heat fluxes, while long-term trends over the 1950-2019 period remain insignificantly small. Furthermore, we find significant changes over the North Atlantic Warming Hole and western North Atlantic associated with more frequent positive NAO phases during the past 30 years. From our analysis, we conclude that analysis increments most likely influence the magnitude of these trends, especially at low latitudes where the impact can be as large as ~2 W m-2 dec-1, while the basin-wide trend pattern remains unaffected. The net effect of the found regional changes in fluxes is assessed by the spatial average trend over the whole North Atlantic north of 26°N, which yields a positive but statistically insignificant trend of 0.5 W m-2 dec-1 over the past 70 years. Potential implications for trends in the AMOC are discussed. 
A method to determine the dissolution and erosion rates of marly gypsum samples from Ripon, UK
Authors: Williams Gabriella , Bowman Elisabeth , Bau Domenico , Banks Vanessa
Published: February 2023

Ripon is a town affected by frequent collapse sinkholes that occur due to the rapid dissolution of the underlying gypsum. This gypsum is interbedded and mixed with low solubility but easily water weakened calcareous marl. Construction sites underlain by cavities can be remediated, but if even small flow paths remain, new cavities can appear in close proximity. Dissolution rates previously determined for gypsum have either been on high purity specimens or do not consider the insoluble impurities. It is therefore important to understand the role of interbedded calcareous marls in controlling cavity distribution and growth. A method is proposed to evaluate the effect of marl impurity on gypsum dissolution rates in this area.For the dissolution test, water is circulated through a hole drilled in a gypsum specimen from Ripon. As the gypsum dissolves, the marl could detach and settle, become suspended or also dissolve. If it remains attached, however, it could impede further gypsum dissolution. Conductivity, total dissolved solids (TDS) and pH of the water are monitored and the test continues until the conductivity has stabilised. This indicates that the water is saturated with gypsum and dissolution has ceased. The water is then evaporated to recover suspended solids, which are put through particle size distribution (PSD) sieves. The post-test specimen mass is added to the recovered solid mass and compared to the pre-test mass.After testing, mass loss is estimated from both conductivity and TDS curves, and these are compared to measured mass loss. Changes in pH are taken to indicate dissolution of calcareous components in the marl. The conductivity curve is used to find the dissolution rate constant of the specimen, and its cross-section is visually inspected to check the dissolution pattern. The PSD is used to study transport and deposition of insoluble material. Results are combined to assess the influence of marl on gypsum dissolution and sinkhole development, which can be applied both in Ripon and elsewhere.
Quantifying the accuracy of large time-steps in highly oscillatory systems
Authors: Andrews Timothy , Wingate Beth , Shipton Jemma
Published: February 2023

There is an ever-increasing demand for longer and higher resolution numerical simulations of the weather and climate. To achieve this with reasonable wall-clock times, it is desirable to use as large a time-step as possible, whilst retaining a stable and accurate solution. However, this is very challenging in the presence of highly oscillatory linear waves; there are explicit time-step limits and losses in accuracy with implicit methods. This talk will highlight where non-linear errors can result from large time-steps and provide metrics for quantifying this. We begin by re-casting the non-linearity as a product of linear waves. In the Rotating Shallow Water Equations (RSWEs), this allows for key dynamics to be expressed as three-wave ‘triad’ interactions. A non-linear ‘triadic’ time-stepping error is computed using linear stability polynomials. A number of explicit and implicit time-stepping methods (such as RK4, TR-BDF2, ETD-RK2) will be compared analytically in the RSWEs. Next, two new test problems enable analyses of large time-step simulations. The first is of a Gaussian perturbation to a RSWE height field. A proposed metric, relating to the kinetic energy distribution over temporal frequency, quantifies phase errors in the height reformation. The second test case initialises linear waves which, via direct- and near- resonant triad interactions, will construct non-linear dynamics. Phase errors with large time-steps can be identified in the corresponding height fields. A first variant of this case will initialise only two waves; this will primarily instigate an energy exchange within a dominant triad. A second version, containing more slow modes, enables a re-distribution of fast mode energy into rings in wavenumber space.
Evaluating the impact of anisotropy and low-permeability layers on high temperature aquifer thermal energy storage performance
Authors: Heldt Stefan , Bauer Sebastian
Published: February 2023

The seasonal storage of heat has the potential to reduce greenhouse gas emissions, since it accounts for the seasonal disbalance between heat production and demand in renewable-based energy-systems. High temperature aquifer thermal energy storage (HT-ATES) is a heat storage technology utilising the subsurface and therefore provides high storage capacity with limited above-ground usage, which is especially required in urban areas. Since the temperature difference between the ambient groundwater and the injected water (> 50 °C) results in density differences, convective buoyancy flow can be induced by HT-ATES. This process leads to an uneven heat distribution over the aquifer thickness, reduced storage efficiency and increased thermal impacts. The occurrence and intensity of buoyancy flow is site-specific, since it depends on operational parameters, such as injection temperature, as well as geological parameters, such as aquifer thickness and especially vertical and horizontal permeability.The geological site considered for HT-ATES storage is located in Hamburg, Germany, using the Miocene Lower Braunkohlensande (brown coal sands) as storage aquifer. This sedimentological formation was deposited in a coastal transition regime between terrestrial and shallow-marine settings and consists mainly of sands. Peat swamps and lagoons formed brown coal, silt and clay layers, which have the potential to hinder convection due to their low permeability, depending on their lateral extent in relation to the size of the induced heat plume by HT-ATES. Lithological classifications of 25 wells provide the data basis for the geological analysis.The aim of this study is to evaluate the influence of thin low permeability layers on induced buoyancy flow and thus HT-ATES performance, as measured by heat recovery. To this end, a site-specific numerical HT-ATES model is created, which simulates the coupled thermo-hydraulic processes. Different scenarios with varied vertical permeability as well as the number and lateral extent of low-permeability layers show the effect on density-driven buoyancy flow and HT-ATES efficiency. Increasing the vertical permeability by a factor of 10 results in an efficiency decrease from 78 % to 57 % in the 10th storage cycle. The findings serve as a process understanding basis for complex heterogeneous facies models of the HT-ATES site, which will be based on the geostatistical evaluation of site data.
Reconstructing the Greenland ice sheet in past warm climates
Authors: Hvidberg Christine S. , Lauritzen Mikkel , Rathmann Nicholas M. , Solgaard Anne M. , Dahl-Jensen Dorthe
Published: February 2023

The stability of the Greenland ice sheet through past glacial-interglacial cycles provides knowledge that can contribute to understanding the future mass loss and contribution to sea level from the Greenland ice sheet in a warmer climate. Paleo-climatic records from ice cores provide constraints on the past climate and ice sheet thickness in Greenland through the current interglacial, the Holocene, 11.7 kyr to present, but is limited to a few ice cores from the central areas. In the previous interglacial period, the Eemian, 130 kyr to 110 kyr before present, the ice core constraints are sparse, and beyond the Eemian, the climate evolution is known from Antarctic ice cores and marine sediments. The limited constraints on the past climate in Greenland presents a challenge for reconstructions based on ice flow modelling. Here we present initial results from an ice flow modelling study using the PISM ice flow model to simulate the evolution of the Greenland ice sheet in the Eemian and the Holocene periods. We discuss how paleo-climatic data from ice cores and marine sediments can be combined with ice flow modelling. We find that the Greenland ice sheet retreated to a minimum volume of up to ∼1.2 m sea-level equivalent smaller than present in the early or mid-Holocene, and that the ice sheet has continued to recover from this minimum up to present day. In all our runs, the ice sheet is approaching a steady state at the end of the 20th century. Our studies show that the Greenland ice sheet evolves in response to climate variations on shorter and longer timescales, and that assessment of future mass loss must take into account the history and current state.
Assessing Performance of a new High Resolution polar regional climate model with remote sensing and in-situ observations: HCLIM in the Arctic and Antarctica
Authors: Torres-Alavez Abraham , Landgren Oskar , Boberg Fredrik , Christensen Ole Bøssing , Mottram Ruth , Olesen Martin , Van Ulft Bert , Verro Kristiina , Batrak Yurii
Published: February 2023

We present results from a new high resolution regional climate model, configured for both the Arctic and the Antarctic, assessed with a range of in-situ and remote sensing datasets. Under the Horizon 2020 PolarRES project, a set of simulations are performed at a spatial resolution of ~12 km over the Arctic and Antarctic regions using the latest version (cy43) of the HCLIM-ALADIN regional climate model. The model includes a thermodynamic sea ice scheme and has been updated with the latest ice sheet masks and improved topography and other physiographic fields. The model will be used to provide climate projections over the 100-year period 2001-2100 for two emission scenarios, and driven on the boundaries by General Circulation Models (GCMs) from the Coupled Model Inter-comparison Project (CMIP6). We also present and evaluate hindcast simulations for the period of 2001 to 2020 over both domains, forced by ERA5 on the boundaries. Model precipitation, temperature, sea ice, and other variables are evaluated with observations from automatic weather stations and satellite data in the polar regions, and additionally compared against the new high resolution (2.5km) Copernicus Arctic Regional ReAnalysis (CARRA) dataset. We also examine the effect of spectral nudging on simulation output. Preliminary results show that HCLIM improves on ERA5, capturing the precipitation, temperature, sea ice cover and ice sheet surface mass balance in both polar regions.In addition, we show that the wealth of earth observation data now available via the ESA climate change initiative and the EUMETSAT climate data programmes are extremely useful tools to the regional climate modelling community. We use example scripts for model evaluation using EO data via an open repository and present user cases that can be replicated by other modelling groups. 
A decade of measurements, which turned Swarm into a lightning hunter
Authors: Slominska Ewa , Strumik Marek , Slominski Jan
Published: February 2023

The ESA Swarm mission has been designed to provide high-precision registrations of the Earth's magnetic field. Since its launch, the constellation, consisting of three LEO satellites, measures the magnetic signals coming from Earth's core, mantle, crust, oceans, ionosphere, and magnetosphere. Nearly a decade of Swarm observations, allowed us to expand main goals of the mission and improve our capabilities of detecting magnetic field fluctuations triggered by powerful thunderstorms.Lightning can generate ultra low frequency fluctuations that leak into the upper ionosphere. This means that some lightning bolts are so powerful that they trigger disturbances in Earth's magnetic field and propagate hundreds of kilometers upwards from the thunderstorm, reaching the altitude of Swarm’s orbit. Thanks to two magnetometers,  the Absolute Scalar Magnetometer ASM and the Vector Fluxgate Magnetometer VFM, Swarm turned into a robust lightning hunter. Gathered analysis, utilizing mainly the VFM registrations, show that averaged amplitude of lightning generated fluctuations reaches magnitude of 0.5-1.3 nT (peak-to-peak for the scalar field), while typical time delay between the lightning occurrence and the satellite detection is 0.2-0.5 s and this indicates that Swarm detects rather a direct propagation of lightning-generated disturbance than effects of excitation of the ionospheric Alfvén resonance, which would require a longer time scale.Since Swarm provides full representations of the magnetic field components, we transform data to the so-called MV frame to extract the maximum amplitude of a given fluctuation regardless of the lightning-satellite mutual orientation and wave polarization. In such a way, Swarm data help to comprehensively characterize  wave properties of detected fluctuations, and this is one of fundamental tasks, especially in the large variety of magnetic field disturbances caused by various types of natural hazard phenomena. 
Validation of an irrigation scheme inside ORCHIDEE land surface model at global scale
Authors: Arboleda Obando Pedro Felipe , Ducharne Agnès , Vargas-Heinz Luiza , Yin Zun , Ciais Philippe
Published: February 2023

Irrigation activities play a key role in food production and consume 90% of freshwater withdrawal worldwide. These activities have a strong impact on water and energy budgets and associated biogeochemical cycles, and can have effects on local and regional climate. Furthermore, irrigation activities are projected to increase due to population growth and climate change. This context has encouraged the inclusion of irrigation in land surface models (LSMs), which simulate the continental branch in earth system models.Here we present an irrigation scheme within the ORCHIDEE LSM that replicates flood and drip techniques. Water demand is calculated as the soil moisture deficit with respect to a target value. This deficit is estimated in the root zone of the crop and grass fraction (which contains both irrigated and rainfed crops), but the demand is limited by the fraction equipped for irrigation and by the water supply, i.e. water available in rivers and aquifers reduced to preserve a minimum volume in each water store for ecosystems. In addition, the scheme prioritizes water abstraction by source (surface or groundwater) according to the Siebert et al. map (2010). Hence, in a gridcell with little groundwater pumping infrastructure, most of the water will be extracted from the river, even if the water demand is not fully supplied. The water finally withdrawn for irrigation is allocated on the surface of the soil column for infiltration, and a maximum irrigation rate is set to prevent runoff production. The user-defined parameters that drive the scheme's response are the root zone depth and soil moisture target, the minimum volume left for ecosystems, and the maximum irrigation rate.For validation, we use this scheme inside ORCHIDEE to run global offline simulations without and with irrigation. We use a set of parameter values that tries to fit the irrigation rates reported by AQUASTAT, while reducing the bias of evapotranspiration in irrigated areas with respect to the satellite-based products. We explore the possible reduction of bias in other variables like leaf area index, water storage anomalies and observed discharge. Finally, we correlate the bias reduction with landscape features to gain insights on the shortcomings of the irrigation scheme and ORCHIDEE.
Quantification of ammonia losses from winter wheat using eddy covariance and low-cost samplers
Authors: Kukowski Sina , Götze Hannah , Wintjen Pascal , Rüffer Jeremy , Pacholski Andreas , Flessa Heinz , Brümmer Christian
Published: February 2023

Ammonia (NH3)emissions stem mainly from agricultural sources and affect environment, climate and human health, thereby concomitantly reducing fertilizer nitrogen use efficiency. Reliable and representative measurements for typical field conditions as well as for potential mitigation options are needed as a basis for recommendations to policy makers and farmers. However, there is still uncertainty about the reliability of different NH3 measurement methods for emissions from low intensity sources, such as synthetic fertilizers, and a lack of data on simultaneous comparative evaluations of different methods. The joint research project NH3-Min aims at comparing combinations of different NH3 samplers and sensors (e. g. acid traps, dynamic chamber, laser-based techniques), flux calculation approaches (e. g. IHF, ZINST, bLs-Windtrax, eddy covariance), and scales (small scale multi-plots, field scale) to accurately quantify emissions and evaluate mitigation options (e. g. use of inhibitors, injection, form of nitrogen).This poster focuses primarily on the quantification of NH3 concentrations and fluxes determined by a quantum cascade laser spectrometer (QCL) within an eddy covariance setup and the comparison to low-cost approaches, such as ALPHA passive diffusion samplers in combination with backwards Lagrangian stochastic (bLs) modelling (Windtrax). Measurements were carried out in Central Germany during the vegetation period in 2021 and 2022 in a winter wheat crop field, which received 3 urea fertilizer applications (to a total of 170 kg N) per year.First results showed that under high ambient NH3 concentrations, time-integrated QCL values compared fairly well with those from ALPHA samplers. Under a low concentration regime, however, a significant underestimation of ALPHA values was observed, thereby providing a basis for an estimation of the method-specific detection limit. High-frequency losses using a co-spectral method in the process of eddy flux calculation were estimated to be in the range of 25 to 30%. We found clear diurnal flux courses and emission peaks after each urea application. The net loss of NH3 summed up to 3.6 kg N ha-1 over the whole measurement period (March – July). In further steps, we will evaluate the performance of the Windtrax model for estimating NH3 losses from field-scale fertilizer applications and investigate the sensitivity of differences in input concentrations on modelled NH3 emissions. Our study is a step towards better comparability and integration of different NH3 measurement techniques and is expected to provide useful tools for robust estimations of NH3 emission factors for synthetic fertilizer applications.The project is supported by funds of the German Government‘s Special Purpose Fund held at Landwirtschaftliche Rentenbank.
Kickstarting scientific engagement with art: An EGU-situ experiment
Authors: Perez Diaz Lucia , Crameri Fabio
Published: February 2023

Science, at its core, is about making sense of the world around us. So it is somewhat ironic that, more often than not, scientific results are presented in ways that leave specialist audiences baffled, and cause the general public to run in the opposite direction. This is worrying because scientific progress relies on effective scientific communication and knowledge exchange.In recent years, we’ve seen a proliferation of examples illustrating how art (or at least a more creative approach) can help us, scientists, overcome some of the barriers between our science and the outside world. These range from contributions highlighting the “how and why” of creating scientifically accurate and universally accessible graphics (e.g. Crameri et al., 2022s-ink, colormaps?), to projects where scientific content is simply the inspiration behind abstract illustration (e.g. Wadsworth et al., Nat. Geosci. 15). The first puts the focus on the information being presented, whilst the second is aimed more strongly at catching the audience’s attention, as the first critical step in engaging with potential readers for a science piece. Whilst they are fundamentally different, both of these extremes (and all the possible art-science crossovers in between) show us the huge power of visual storytelling for science communication.In this contribution, we will experiment withshare a series of interesting geoscientific data visualisations accompanied by short explanations created by a scientist and, illustrateding by an artistinteresting geoscientific facts. Our aim was to create pieces that, through their artistic quality, can originate a spark of curiosity in the viewer strong enough to prompt them to pay closer attention for the length of time required for them to interiorise the scientifically accurates  information being presented. We will collect direct feedback from engaging viewers (in this case EGU GA participants). In doing this, we hope to show, and understand better, the ability of art to kickstart that critical two-step process, where curiosity leads to engagement, which is fundamental for effective communication. And, to generate beautiful office wall decorations in the process. Crameri, F., G.E. Shephard, and E.O. Straume (2022, Pre-print), Effective high-quality science graphics from s-Ink.org, EarthArXiv, https://doi.org/10.31223/X51P78Wadsworth, F.B., Vasseur, J., Anagnostopoulos, I. et al. Estimating pi using geoscience. Nat. Geosci. 15, 246–247 (2022). https://doi.org/10.1038/s41561-022-00928-z
Transpiration in forest ecosystems based on deep learning and sap flow observations
Authors: Hannemann Marco , García-García Almudena , Peng Jian
Published: February 2023

Transpiration (T), the component of evaporation (E) controlled by vegetation, dominates terrestrial Evaporation, but measurements are highly uncertain. In the light of the importance of evaporation for studying the terrestrial water cycle, hydro-climatic extremes such as droughts and heatwaves and land-atmospheric interactions, there is a strong demand on novel approaches to reliably estimate T. Currently available approaches to estimate T mostly rely on its relationship with photosynthesis, but parameterizing this relationship is difficult and estimates of T strongly disagree among each other in terms of magnitude. Moreover, in-situ measurements are scarce and and evaporation cannot be measured directly from space.We developed a hybrid Priestley-Taylor (PT) model using Deep Learning to learn the relationship between T and state variables such as soil moisture, vapor pressure deficit and the fraction of photosynthetic active radiation for different plant functional types (PFTs). We use globally available variables from reanalysis and remote sensing data as forcing to train an artificial neural network on the PT-coefficient α obtained by inverting the PT model on sap flow based ecosystem T. In this way, we can predict Transpiration at local scales independently from hard-to-obtain fluxes like E or vegetation parameters such as stomatal conductance. We evaluate our algorithm against T estimates from flux partitioning methods based on water use efficiency at eddy covariance sites for different PFTs and regions. Also, we compare our estimates with other available products of transpiration like GLEAM, PML-V2 and ERA5-Land. Preliminary results of this research showed that the developed model can learn the relationship between T and few influencing variables, without incorporating variables such as net radiation or GPP. Our findings contribute to dissolving the scarcity of T estimates in forest ecosystems based on actual observations. Future work is needed to apply our method to the larger scale for studying spatial patterns of T, e.g. across the European continent.