bluuebunny/crossref_metadata_2025 huggingface dataset:
Differentiable modeling to unify machine learning and physical models and advance Geosciences
Authors: Shen Chaopeng , Appling Alison , Gentine Pierre , Bandai Toshiyuki , Gupta Hoshin , Tartakovsky Alexandre , Baity-Jesi Marco , Fenicia Fabrizio , Kifer Daniel , Liu Xiaofeng , Li Li , Feng Dapeng , Ren Wei , Zheng Yi , Harman Ciaran , Clark Martyn , Farthing Matthew , Kumar Praveen
Published: February 2023

Process-Based Modeling (PBM) and Machine Learning (ML) are often perceived as distinct paradigms in the geosciences. Here we present differentiable geoscientific modeling as a powerful pathway toward dissolving the perceived barrier between them and ushering in a paradigm shift. For decades, PBM offered benefits in interpretability and physical consistency but struggled to efficiently leverage large datasets. ML methods, especially deep networks, presented strong predictive skills yet lacked the ability to answer specific scientific questions. While various methods have been proposed for ML-physics integration, an important underlying theme  — differentiable modeling — is not sufficiently recognized. Here we outline the concepts, applicability, and significance of differentiable geoscientific modeling (DG). “Differentiable” refers to accurately and efficiently calculating gradients with respect to model variables, critically enabling the learning of high-dimensional unknown relationships. DG refers to a range of methods connecting varying amounts of prior knowledge to neural networks and training them together, capturing a different scope than physics-guided machine learning and emphasizing first principles. In this talk we provide examples of DG in global hydrology, ecosystem modeling, water quality simulations, etc. Preliminary evidence suggests DG offers better interpretability and causality than ML, improved generalizability and extrapolation capability, and strong potential for knowledge discovery, while approaching the performance of purely data-driven ML. DG models require less training data while scaling favorably in performance and efficiency with increasing amounts of data. With DG, geoscientists may be better able to frame and investigate questions, test hypotheses, and discover unrecognized linkages. 
How much Desert Dust do Aircraft Engines Ingest at Major Airports?
Authors: Ryder Claire , Bezier Clement , Dacre Helen , Clarkson Rory , Marinou Eleni , Proestakis Manolis , Amiridis Vassilis , Vaughan Mark , Kipling Zak , Benedetti Angela , Parrington Mark
Published: February 2023

Mineral dust is the most abundant aerosol in the atmosphere and in particular regions exists in high concentrations. Ingestion of dust by aircraft engines can result in erosion, corrosion or a build-up of deposits damaging internal components. A move towards more efficient engines over recent years restricts capacity to tolerate detrimental impacts in engines. Air traffic in arid areas such as the Middle East has also increased dust exposure. However, it is not currently known how much dust is ingested by aircraft during take-off and landing. In order to quantify this, the vertical profile of dust is required. Here we present a climatology of vertical profiles of dust from the ECMWF Copernicus Atmospheric Monitoring System (CAMS) reanalysis at 10 major global airports, as well as their seasonal and diurnal variability, between 2003-2020. We evaluate the CAMS dust profiles against spaceborne lidar retrievals of dust from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard the CALIPSO satellite using both the standard NASA Level 3 product and the LIdar climatology of Vertical Aerosol Structure (LIVAS) product. Finally, using expected aircraft ascent and descent rates and associated mass flow into an engine, dust dose is calculated for take-off, climb, descent, hold, approach, land and taxi phases, as well as for the entire ascent/descent at different airports, using both CAMS and CALIOP datasets.We show that vertical distribution of dust varies significantly between airports and across seasons, which has a large impact on the total engine dust ingestion. Diurnal dust variations at some airports such as Dubai are extremely large, with night time surface concentrations reduced by over 20%.  Vertical profiles from CAMS show considerable differences to the standard CALIOP L3 retrievals, though agreement with LIVAS profiles is much better. Aircraft engine dose is found to be highest for Delhi (where dose exceeds 7g for a single descent in summer), Niamey and Dubai. During ascent, ingestion is largest during the take-off phase of flight, such that airports with large concentrations of lower altitude dust incur higher doses. During descent, dose is strongly dependent of the altitude of holding pattern relative to the altitude of maximum dust concentration, such that Delhi and Dubai incur the largest dust dose. Therefore, it is recommended that measures to reduce dust ingestion are airport-specific, and could include practices such as night time take-off and adjustment of holding pattern altitude.
LA-ICP-MS U-Pb carbonate geochronology and its geological applications
Authors: Wu Shitou , Roberts Nick , Lan Zhongwu
Published: February 2023

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb geochronology for carbonate minerals, calcite in particular, is rapidly gaining popularity as an absolute dating method. In this study, we review the latest technical progress in LA-ICP-MS carbonate geochronology, including the pre-screening strategies (on-line spot selection with a threshold, image-guided approach, and image-based approach), preferred instrumentation (Q-ICP-MS, SF-ICP-MS and MC-ICP-MS), calibration methods, common Pb corrections and the development of reference materials, with the aim of further improving the precision and accuracy of this technique. We emphasized the characterization of two calcite reference materials (TLM and LSJ07) for micro-beam U-Pb geochronology and C, O isotope ratio measurements. The latest geological applications of LA-ICP-MS U-Pb carbonate geochronology in dating of diagenesis and hydrothermal activity were reviewed.
Monitoring and Understanding Land Subsidence in Joshimath: An InSAR and Ground-based Study
Authors: Garg Shagun , Karanam Vamshi , Motagh Mahdi
Published: February 2023

Joshimath - a small hilly village in Uttarakhand, India is facing severe land subsidence. More than 600 houses and roads and roads have developed cracks, and the government has ordered the immediate evacuation of families in the area.Joshimath has seen significant urbanization in recent years due to its strategic location and the increasing popularity of tourism and adventure sports in the region. There has been a growing demand for infrastructure and services to accommodate the influx of tourists, leading to the development of new hotels, resorts, and other facilities. Over the years, several hydroelectric, road, and tunnel construction projects have also been undertaken in the region. In order to better understand and mitigate the risk of landslides in this area, it is important to implement a robust monitoring system. Interferometric Synthetic Aperture Radar (InSAR) is a remote sensing technique that has been used successfully in the past to monitor landslides and other ground deformation events. In this study, we used InSAR to monitor land subsidence in Joshimath over a period of 20 months (May 2021 - Jan 2023). We collected radar data from Sentinel-1 and performed PSInSAR analysis. Our preliminary analysis revealed continuous deformation of the order of 4cm/year in the region. Specific locations are selected for further detailed analysis, and field work is being carried out to provide additional information such as effects of subsidence and vulnerability of the area. This information can be used to develop a comprehensive understanding of the subsidence problem in Joshimath. 
Observation-only learning of 4DVarNet neural schemes for the reconstruction of sea surface turbidity dynamics from gappy satellite images
Authors: Dorffer Clément , Jourdin Frédéric , Mouillot David , Devillers Rodolphe , Fablet Ronan
Published: February 2023

Optical remote sensing  is increasingly used to assess various sea surface biogeochemical parameters (e.g., Chl-a, turbidity). If today’s systems offer better spatiotemporal coverage, the space-time sampling depends on both the satellite orbit and the cloud cover. The resulting sea surface observations generally present large proportions of missing data, making their completion challenging.Here, we explore neural interpolation schemes as an approach for image gap filling, and their training from observation-only datasets with large missing data rates (with a mean of 65% of missing data and up to 100% for the worst days of the time-series), i.e., when no reference gap-free data are available to run a classic supervised learning approach. We propose and assess different strategies based on real or simulated missing data patterns to discard parts of the available data for learning. We combine these learning strategies with 4DVarnet schemes, which are state-of-the-art neural interpolation schemes backed on a variational data assimilation formulation. The approach was tested in a turbidity reconstruction context, using a multi-modal satellite dataset (CMEMS product: oceancolour_med_bgc_l3_my_009_143) at 1km spatial resolution with daily images from year 2019 to 2021, off the French coast in the western Mediterranean Sea.Our learned variational algorithm significantly outperforms state-of-the-art interpolation techniques, including optimal interpolation and DINEOF, with a 37% gain in RMSE reached in preliminary tests.
Auroral oval identification based on Swarm magnetometer data
Authors: Decotte Margot , Hatch Spencer , Laundal Karl , Reistad Jone
Published: February 2023

Following the work done with the DMSP spectrometer data to derive the auroral occurrence probability in all covered MLat-MLT sectors above 50 degrees MLat (Decotte et al. 2023), here we use the Swarm magnetometer data to extract the probability to detect magnetic field perturbations in the East--West direction. We derive the integrated spectral density from the magnetic field data in a given frequency band, and we define a minimum power threshold above which fluctuations would indicate field-aligned currents. We obtain MLat-MLT distributions of magnetic field fluctuations for various geomagnetic conditions. We find strong similarities between the preferred region of magnetic perturbations and the Xiong and Lühr auroral boundaries (2014), suggesting that the auroral oval morphology could be investigated through magnetic field spectral power estimates. We compare the magnetic field fluctuation probability with the auroral occurrence probability (DMSP particle data) and we find a recurrent dawn-dusk asymmetric pattern in both distributions.  
Simulating Ocean Alkalinity Enhancement along the European Coast in an Earth System Model
Authors: Mehendale Neha , Wey Hao-wei , Kemena Tronje , Keller David , Oschlies Andreas
Published: February 2023

To assess the potential of coastal ocean alkalinity enhancement as a CO2 removal option for climate change mitigation, the Flexible Ocean and Climate Infrastructure (FOCI) earth system model was used to simulate alkalinity addition at the European coast open to the North Atlantic. FOCI has a global ocean resolution of 0.5° which can be regionally refined to 0.1° with a two-way nesting approach. The model was run in emission driven mode, starting with a linear ramp up from 2025 to 2035, after which alkalinity equivalent of 1Gt Ca(OH)2 per year was added in both resolution configurations from year 2035 to 2100 along the European coastline in a high and low emission scenario. To assess regional efficacies, the coast was divided into subsections. We illustrate the importance of adequate model resolution for simulating coastal alkalinity deployment, and show how each coastal region has a different CO2 uptake efficiency that is caused by differences in the regional environmental and hydrodynamic conditions.
Projected changes on quasi-resonant amplification by CMIP5 and CMIP6 toward the persistence in extreme summer weather events
Authors: Oliveira Guimarães Sullyandro , E. Mann Michael , Rahmstorf Stefan , Petri Stefan , Kornhuber Kai , Coumou Dim , A. Steinman Byron , Brouillette Daniel , Christiansen Shannon
Published: February 2023

 
High-amplitude quasi-stationary atmospheric Rossby waves with zonal wave numbers 6 to 8 associated with the phenomenon of quasi-resonant amplification (QRA) have been linked to persistent summer extreme weather events in the Northern Hemisphere. We project future occurrence of QRA events based on an index derived from the zonally averaged surface temperature field, comparing results from CMIP5 and CMIP6 (Coupled Model Intercomparison Projects) climate projections. Under the scenarios analyzed, there is a general agreement among models, with most simulations projecting a substantial increase in QRA index. Larger increases are found among CMIP6-SSP585 (42 models, 46 realizations) models with 85% of models displaying a positive trend, as compared with as compared with 60% of CMIP5-RCP85 (35 models, 75 realizations), and a reduced spread among SSP585 models. The CMIP6-SSP370 (24 models, 28 realizations) simulations display qualitatively similar behavior to SSP585, indicating a substantial increase in QRA events under business-as-usual emissions scenarios. Our analysis suggests that anthropogenic warming will likely lead to an even more substantial increase in QRA events (and associated summer weather extremes) than our previous analysis of CMIP5 simulations.
Development, data modelling of environmental geochemical monitoring of fluvial (suspended, river bottom, floodplain) sediments using unique automated and passive sampling for the contamination risk assessment according to the EU WFD in the Danube Basin
Authors: Kovács Zsófia , Jordán Győző , Szabó Péter , Bálint Mária ,   SIMONA Project Team
Published: February 2023

This study reports on the unique results of the recently concluded Sediment-quality Information, Monitoring and Assessment System to Support Transnational Cooperation for Joint Danube Basin Water Management (SIMONA) project, the largest of its kind in Europe, which was carried out in 2018-2022 as a project of the EU DTP aiming at delivering a ready-to-deploy sediment-quality monitoring system for the effective and comparable measurements and assessment of sediment quality in surface waters in the Danube River Basin in accordance with the EU Water Framework Directive (WFD). The project has developed, tested, demonstrated an innovative environmental geochemical monitoring platform of fluvial (suspended, river bottom and floodplain) sediments using state-of-the-art automated and passive sampling technology for the contamination risk assessment according to the EU WFD in the Danube Basin. Time series analysis and signal processing of one year multi-variate and multi-matrice monitoring data could be used to identify the geochemical background, temporal trends, periodicities and contamination events in the studied EU-defined Hazardous Substances. Since the applied technology, methods and data interpretation is fully consistent with EU legislation risk assessment, results may provide a ‘best solution’ for the spatial and temporal discrimination of contamination. Results of biological contamination assessment of sediments using microbial tests are also presented.Keywords: data analysis, geochemistry, mobility, speciation, enrichment, time series analysis
Analyzing the reliability of in situ soil moisture measurements for satellite product validation: What makes fiducial reference measurements fiducial?
Authors: Himmelbauer Irene , Gruber Alexander , Aberer Daniel , Preimesberger Wolfgang , Stradiotti Pietro , Dorigo Wouter A. , Boresch Alexander , Tercjak Monika , Gibon Francois , Mialon Arnaud , Richaume Philippe , Kerr Yann , Diez Garcia Raul , Crapolicchio Raffaele , Sabia Roberto , Scipal Klaus , Goryl Philippe
Published: February 2023

To this day, in situ soil moisture data is viewed as ground truth by the satellite soil moisture (SSM) community. In general, little is still commonly known regarding the traceability of ground measurement uncertainty and their overall in uncertainty budget, which can impact satellite SSM product quality assessments.Within ESA’s “Fiducial Reference Measurement for Soil Moisture (FRM4SM, May 2021 - May 2023)” project, objectives are set towards building fully characterized and traceable (i.e., fiducial) in situ measurements following community-agreed guidelines from the GEOS/CEOS Quality Assurance for Soil Moisture (QA4EO) framework. These so called “fiducial reference data” (FRM) should have associated Quality Indicators (QI) attached to evaluate their fitness for purpose building upon agreed reference standards (SI if possible). Moreover, such data should be easily and openly accessible, validation case studies should demonstrate their utility and reliability, and protocols and procedures should be established for the usage of such FRM datasets to make scientific studies intercomparable and reproducible.As part of the FRM4SM project, the following questions were addressed using the International Soil Moisture Network (ISMN) as a ground reference database and the Soil Moisture and Ocean Salinity (SMOS) mission as an example satellite product:(1) What makes “fiducial reference data” fiducial?(2) Is the creation of a globally-representative FRM subset already feasible for SSM?(3) What are the current limitations of in situ observations that limit fiduciality?(4) What is needed to create a full traceability chain from in situ point measurements to the satellite footprint scale?In this presentation, we will discuss these questions in detail and report on related findings of the FRM4SM project.
Speciation of soil organic phosphorus: Steps from NMR spectra to bioavailability
Authors: Schleucher Jürgen , Haddad Lenny , Paneque Marina , Wardle David , Vincent Andrea , Giesler Reiner
Published: February 2023

Phosphorus (P) is an essential element for all life on Earth. Understanding P cycling is in the context of global change crucial both for modelling of global biogeochemical cycles and for agricultural productivity. Recently, concerns about the future of P fertilizer supply have prompted much research on soil P and method development. 31P Nuclear Magnetic Resonance (NMR) Spectroscopy has been used to analyse speciation of inorganic and of organic P species (Po), using in alkaline soil extracts1. The region containing signals from phosphomonoesters is particularly important because these compounds are considered biologically active, but there are still significant problems to be resolved particularly for this region of P NMR spectra, including: 1. Poor signal resolution often makes quantification of Po species in this region very challenging. 2. It is unclear if observed signals are due to free P species, or originate from P compounds bound to high-molecular weight soil matter. 3. The question needs to be addressed how signals observed in alkaline extracts relate to P species that were originally present in the soil. Here we present two approaches to address these problems:In a study of a 5000-year soil chronosequence in Northern Sweden2, we found that humus P composition barely changed, although time since fire varied up to 5000 years. We will present a new method to back-calculate original Po speciation from the observed composition. Results of this method indicate absence of “recalcitrant” Po species, and instead indicate that most Po was originally present as biologically active P metabolites, probably present in live soil organisms. We will discuss implication of these findings for P biogeochemistry.Second, we studied a diverse group of soils to address how the poorly resolved phosphomonoester region should best be analysed. Deconvolution techniques are required to handle the overlap, but a better understanding of the nature of the signals is required for reliable quantification. Based on combined analysis of 1D 31P NMR, 2D 1H-31P NMR and 31P linewidth measurements, we present a strategy for quantification of phosphomonoester species, as next step in linking observed Po speciation to P bioavailability. (1) Cade-Menun BJ, Preston CM (1996) A comparison of soil extraction procedures for 31P NMR spectroscopy. Soil Sci 161:770–785(2) Andrea G. Vincent, Jürgen Schleucher, Reiner Giesler, David A. Wardle (2022) Soil phosphorus forms show only minor changes across a 5000‑year‑old boreal wildfire chronosequence. Biogeochemistry (2022) 159:15–32  https://doi.org/10.1007/s10533-022-00910-2(3) Vestergren J, Vincent AG, Jansson M et al (2012) High-resolution characterization of organic phosphorus in soil extracts using 2D 1H–31P NMR correlation spectroscopy. Environ Sci Technol 46:3950–3956. https:// doi. org/ 10. 1021/ es204016h
Five-year inter-annual variation in the net landscape carbon balance of a managed boreal forest landscape in Sweden
Authors: Chi Jinshu , Klosterhalfen Anne , Nilsson Mats , Laudon Hjalmar , Lindroth Anders , Kljun Natascha , Wallerman Jörgen , Fransson Johan , Lundmark Tomas , Peichl Matthias
Published: February 2023

The boreal biome exchanges large amounts of carbon (C) with the atmosphere and thus significantly affects the global climate. A managed boreal landscape typically consists of various sinks and sources of carbon dioxide (CO2), methane (CH4), and dissolved organic and inorganic carbon (DOC and DIC) across forests with different stand ages, mires, lakes, and streams. Due to the spatial heterogeneity, a full understanding of the landscape-scale C balance requires capturing all C fluxes. Here, we investigate the five-year interannual variability in the net landscape carbon balance (NLCB) by compiling terrestrial and aquatic fluxes of CO2, CH4, DOC, DIC, and harvested C obtained from 2016 to 2020. For that purpose, we applied tall-tower eddy covariance measurements, stream monitoring, and remote sensing of biomass stocks (i.e. harvested C via clearcutting) to estimate the landscape-scale C fluxes across the land-water-atmosphere continuum for an entire boreal catchment (~68 km2) in Sweden. Our results show that this managed boreal forest landscape was a net C sink during 2016-2020 (123 ± 63 g C m-2 yr-1) with the lowest and highest sink-strength occurring during a wet year 2017 (16 g C m-2 yr-1) and a drought year 2019 (182 g C m-2 yr-1), respectively. The net landscape-atmosphere CO2exchange was the dominant component of NLCB, followed by the C export via harvest and streams. We further found that global radiation and vapor pressure deficit regulated the inter-annual variations of NLCB, whereas forest biomass and source area contribution of mires determined its spatial variability. Overall, our multi-year NLCB investigations provide a holistic understanding of the inter-annual variations in NLCB of managed boreal forest landscapes to better evaluate their potential for mitigating climate change.
The future of forests: thermal acclimation in the JULES land surface model
Authors: Oliver Rebecca , Mercado Lina , Clark Doug , Harris Phil , Medlyn Belinda
Published: February 2023

A key driver of the terrestrial carbon sink is photosynthesis. Accurate representation of this process in Earth System models is important to help understand and quantify the resilience of the global carbon sink to future climate change. In the JULES land surface model (the land surface component of the UK Earth System model - UKESM), we implement thermal adaptation and acclimation of photosynthesis using the latest scheme from Kumarathunge et al., (2019), which is based on data from 141 C3 species covering a diverse range of biomes from tropical rainforest to arctic tundra. Additionally, we explore the sensitivity of photosynthetic acclimation to rising atmospheric CO2 concentrations. In model simulations using forcing based on RCP8.5 to explore the model response to increasing temperatures, we show that thermal adaptation and acclimation has a positive effect on GPP that persists to 2050, but the size of the response diminishes over time. Broken down by biome, this effect is most notable in the tropics. Additionally, opposite effects of temperature adaptation and acclimation are seen in tropical (adaptation effect decreases GPP over time, whereas acclimation increases GPP) versus temperate and boreal regions (adaptation effect is constant, whereas acclimation decreases GPP over time). The attenuation of the adaptation effect in the tropics is because high temperatures in this region cause a shift in the Jmax:Vcmax ratio such that photosynthesis becomes light-limited earlier (in contrast to simulations where thermal adaptation and acclimation is not activated). The light-limited rate of photosynthesis is less sensitive to increasing atmospheric CO2 concentrations, therefore photosynthetic rates are reduced. This effect is not seen in the temperate/boreal regions because of the cooler temperatures here. Thermal acclimation results in seasonal shifts in the optimum temperature for photosynthesis. In the tropics, the optimum temperature for photosynthesis increases compared to control simulations without acclimation allowing for higher photosynthetic rates at leaf temperatures around the optimum. This increases the resilience of tropical vegetation to higher temperatures and heat extremes. In the temperate and boreal region, thermal acclimation lowers the optimum temperature for photosynthesis to adjust photosynthetic capacity to cooler spring temperatures. Acclimation of the Jmax:Vcmax ratio to increasing atmospheric CO2 concentration results in large decreases in GPP as CO2 concentrations rise across all biomes. Enabling thermal adaptation and acclimation in the JULES land surface model therefore leads to a lower CO2 fertilisation response of tropical vegetation as photosynthesis transitions from CO2-limited to light-limited earlier, however vegetation productivity benefits from adjustment of its thermal sensitivity of photosynthesis to local temperatures.
Benchmark sedimentary records recovered from the Iberian margin during IODP Expedition 397
Authors: Hodell David , Fatima Abrantes , Carlos Zarikian ,   IODP Expedition 397 Scientists
Published: February 2023

The Iberian margin is a well-known source of rapidly accumulating sediment that preserves a high-fidelity record of millennial climate variability. Previous studies of piston cores and IODP Site U1385 demonstrated that surface, and deep-water climate signals from the region can be correlated precisely to the polar ice cores in both hemispheres and with European terrestrial sequences. The continuity, high sedimentation rates, and fidelity of the climate signals recorded in Iberian margin sediments make this region a prime target for ocean drilling. The primary objective of IODP Expedition 397 was to extend these remarkable paleoclimate records beyond the range of existing piston and IODP cores -- currently limited to the last 1.5 million years. To this end, we recovered a total of 6176.7 m of core at four sites (U1586, U1587, U1385, and U1588) arranged along a bathymetric transect (4691, 3479, 2590 and 1339 mbsl, respectively) to intersect each of the major subsurface water masses of the eastern North Atlantic. The bathymetric transect provides an opportunity to study the history of deep-water circulation, ventilation and carbon storage in the deep eastern North Atlantic and its relationship to changing atmospheric CO2. Sediments from all sites display strong cyclicity in bulk sediment properties, permitting the development of orbitally-tuned time scales and correlation with classic Mediterranean cyclostratigraphy. We will report on existing results from Site U1385 drilled during Expedition 339, new preliminary results from Expedition 397 sites (including the reoccupation of Site U1385), and discuss the future potential of Iberian margin sediments for providing benchmark paleoclimate records for the late Miocene through Quaternary. 
Quantifying the global impact of nitrogen deposition on persistent and vulnerable soil C pools
Authors: Willard Sam , Waring Bonnie
Published: February 2023

Soils play a major role in mitigating climate change, as they sequester vast stocks of organic carbon and thereby buffer atmospheric CO2 concentrations. Inorganic nitrogen has been shown to have varying effects on soil C, sometimes promoting soil C buildup yet enhancing C loss in other cases. This contradiction may be a function of how soil C is stored, with C in particulate organic matter (POM) being much more susceptible to microbial decomposition than C in mineral-associated organic matter (MAOM). We have compiled a global dataset of over 200 papers which used a rigorous density fractionation methodology for quantifying stocks of C in POM and MAOM. Preliminary results suggest that inorganic N addition via deposition decreases organic C storage in MAOM, while not affected POM. Further, soil C storage in both pools increased with lower pH, countering our hypothesized negative effect of acidification on microbial activity.
Medium range ensemble streamflow forecasts for hydropower dams of the Brazilian National Interconnected System
Authors: Gama Cléber , Siqueira Vinicius , Kolling Neto Arthur , Paiva Rodrigo , Fan Fernando , Collischonn Walter , Quedi Erik , Petry Ingrid , Silveira Reinaldo , Freitas Camila , Paranhos Cassia
Published: February 2023

Short-to-medium range streamflow forecasting is essential for planning and operating hydropower plants (HPPs). The Brazilian National Interconnected System (SIN) is composed of more than 150 HPPs that are located over a wide range of climate and hydrological conditions. Forecasts of natural inflow into the SIN reservoirs are important to establish optimal operating rules to reduce costs with other energy sources, therefore influencing the prices in the energy market. The objective of this work is twofold: (i) evaluate the skill of ensemble streamflow forecasts for the SIN hydropower plants based on continental-scale hydrological modeling (MGB-SA) and medium-range ECWMF rainfall forecasts (MGB-ECMWF), and (ii) compare the MGB-ECMWF forecasts to those produced operationally by the Electric System National Operator (ONS). The MGB-ECMWF predictions were additionally bias-corrected and updated using quantile mapping and auto-regressive model approaches, and were assessed in the period from 2015 to 2020 in terms of weekly averages. The forecast skill was estimated relative to both streamflow climatology and persistency using the CRPS metric, while the comparison between MGB-ECMWF and operational forecasts was performed using deterministic metrics typically adopted by ONS. The skill of MGB-ECMWF forecasts was substantially improved (especially in the first week) by the use of output correction methods, which were demonstrated to be essential for quantitative streamflow forecasting using a continental-scale hydrological model. The relative performance between ONS and MGB-ECMWF forecasts was quite variable (exhibiting positive and negative values) over the geographical extent of the SIN, although in several locations the MGB-ECMWF forecasts have performed equal to or even better than those issued by ONS. Finally, the results presented here provide insights for investigations and applications of streamflow forecasts using continental-scale modeling and simple output correction techniques, which can bring benefits, for example, in the optimization of the reservoir operation and electricity generation.Acknowledgments: This work presents part of the results obtained during the project granted by the Brazilian Agency of Electrical Energy (ANEEL) under its Research and Development program Project PD 6491-0503/2018 – “Previsão Hidroclimática com Abrangência no Sistema Interligado Nacional de Energia Elétrica” developed by the Paraná State electric company (COPEL GeT), the Meteorological System of Paraná (SIMEPAR) and the RHAMA Consulting company. The Hydraulic Research Institute (IPH) from the Federal University of Rio Grande do Sul (UFRGS) contribute to part of the project through an agreement with the RHAMA company (IAP-001313).
High-altitude aerosol characterization and PMF analysis of PM1 at the Helmos Mt station during the CALISHTO campaign
Authors: Eleftheriadis Konstantinos , Zografou Olga , Gini Maria , Fetfatzis Prodromos , Granakis Konstantinos , Diapouli Evangelia , Manousakas Manousos Ioannis , Foskinis Romanos , Papayannis Alexandros , Nenes Athanasios
Published: February 2023

This study presents part of the results of the CALISHTO campaign (Cloud-AerosoL InteractionS in the Helmos Background TropOsphere) that took place in autumn 2021 at the free-troposphere high-altitude Helmos station (2314 m a.s.l.). A Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM, Aerodyne) was deployed among other instruments (AE31, PVM-100, SMPS, EC/OC analyzer) in the framework of the campaign. The chemical characterization of the non-refractory PM1 (NR-PM1), the influence from the Boundary Layer / Free Troposphere, the origin of the incoming masses and the influence of clouds were studied. The sources of PM1 including the non-refractory species of ACSM (organics and inorganics) combined with the equivalent black carbon were also investigated by applying the PMF model to the combined dataset. The results showed that there is a great variability of aerosol characteristics depending on the height of the PBL and the origin of the air masses. During September the station was exposed to PBL emissions, and thus displayed much higher mass concentrations of NR-PM1 than October and November. Concerning the sources of PM1, different types were identified with ammonium sulphate and oxygenated organics being predominant, as expected for aged aerosol with the degree of ageing investigated against air mass origin and microphysical parameters.  
Imprint of ocean currents on signicant wave height
Authors: Wang Han , Villas Bôas Bia , Vanneste Jacques , Young William
Published: February 2023

Ocean currents have been observed to impact the spatial distribution of significant wave height (hereafter "Hs") of surface gravity waves profoundly, with implications for air-sea fluxes, extreme waves, and error budget in satellite observations. In this work, we derive analytic formulas that relate Hs to current velocities under the weak-current approximation, cross-validate the results with WAVEWATCH III, and find implications potentially useful for observational and modelling studies. First, we show that when swell-like surface waves interact with a localized current, caustics, where rays cross in real space, do not lead to singularities in Hs if the wave energy spectra have a realistic directional spread in wavenumber space. This has implications for understanding the origin of freak waves, where caustics have been postulated as a possible source. Then, we consider another regime where weak turbulent flows are considered. Analytic formulas are found that deterministically link the patterns of Hs to currents. The formulas' statistical counterparts are applied to study how the spectral slopes, amplitudes and directionality of Hs are related to currents. Our results demonstrate that the variations of Hs are controlled by the rotational component of the currents, suggesting the potential of using information from surface wave to infer current properties in real observations, or vice versa.
Exploring Characteristics of Turbulent Density Fluctuations in the Arctic Ionosphere with Multi-Point Measurements
Authors: Rexer Theresa , Spicher Andres , Vierinen Juha , Kvammen Andreas
Published: February 2023

Turbulence studies look at how energy is transferred between temporal and spatial scales (or wavenumber) by analyzing the power spectral density or structure function of a measured turbulent environment.In the high-latitude ionosphere, the spatio-temporal characteristics of turbulent density fluctuations are not well understood. Currently, these are generally measured in-situ, using data from satellites or rockets that provide instantaneous measurements along the track.However, to obtain a complete description of the fluctuating fields, time-series of volumetric measurements are needed.In this work, we develop tools to characterize the statistical properties of ionospheric density fluctuations using multi-point measurements that are applicable to incoherent scatter radars such as the upcoming EISCAT_3D.We utilize data from the AMISR radars in Resolute Bay, Canada, and compute the structure functions of ionospheric electron density fluctuations under various seasonal and geophysical conditions. We examine the nature of the fluctuations associated with multiple polar patches in more detail, shedding light on how energy is redistributed across the scales. With the upcoming EISCAT_3D radar, this project aims to investigate and resolve outstanding issues about the structuring of auroral dynamics and the physics involved in creating density irregularities. 
Compound events from the databases
Authors: De Michele Carlo , Banfi Fabiola , Meroni Viola
Published: February 2023

Compound climate-related (or weather-related) events are complex events characterized by the interactions between various physical processes across multiple spatial and temporal scales, generated by meteorological variables, and provoking extreme impacts. Compound climate-related events often include the joint occurrence of multi-hazards like landslides and floods, or heatwaves, droughts and wildfires.In literature, databases of natural hazards are in general single hazard, like databases of floods (European Flood Database, AVI database), landslides (Global Fatal Landslide Database , AVI database), droughts (European Drought Observatory).The assessment and understanding of compound events requires an integrated perspective, with the integration of data from multiple variables, combining multiple databases.In this presentation, we try to address this emerging need, illustrating a possibility of building a compound events database, and presenting some examples.
Investigating ELVE photometric waveforms with elementary electromagnetics
Authors: Luque Estepa Alejandro , Bjørge-Engeland Ingrid , Li Dongshuai , Østgaard Nikolai , Marisaldi Martino
Published: February 2023

ELVEs are quickly expanding rings of light emissions excited in the lower ionosphere by the electromagnetic pulse of an electric discharge in a thundercloud. They are commonly observed from space platforms and have been reported in conjunction with other atmospheric-electricity events. One motivation to investigate ELVEs is that their signal may provide insight into the discharge that created them. Until now the modeling of ELVES has either relied on strong simplifications or on the Finite-Difference Time-Domain (FDTD) method to directly solve the Maxwell equations. One limitation of the latter is that non-axisymmetrical discharges (with a slanted channel or a non-vertical magnetic field for example) require computationally expensive, fully three-dimensional meshes, which makes parametric studies of the ELVE features slow and cumbersome.  We show here that elementary electromagnetic theory allows one to model ELVEs, even non-axisymmetrical ones, with sufficient accuracy at little computational cost. We then apply our methods to the parametric study of ELVE photometric waveforms as recorded by space-based instruments.
Overview of Sudan Groundwater Resources Under Challenged Political Conditions
Authors: Abdel-Magid Hisham
Published: February 2023

Overview of Sudan Groundwater Resources Under Challenged Political Conditions

The presentation highlights the status quo of groundwater as a valuable yet undermanaged resource in Sudan. The political instability following public protests by the end of 2018 and the following deposition of a thirty-years governing regime affected the Sudanese national focus in different aspects. Regionally, the continued dispute over the River Nile water allocation and agreements, especially while Sudan being in a middle position between two countries Egypt and Ethiopia, with regards to the construction of The Great Ethiopian Renaissance Dam (GERD) has put another focus of perspective over the River Nile as a vital water resource, leaving lesser attention in terms of exerted efforts towards agreement on transboundary groundwater aquifers, such as the Nubian aquifer or the unique instance of AL-Gash aquifer. As a third angle, the presentation would highlight the impact of international support and intervention over the aforementioned context as well as the need to support Sudan considering its struggling economy. The conclusion would underpin main points of interest for enriching dialogue and discussion towards sustainable utilisation of groundwater resources in Sudan and its overall strategy for water resources management.

Keywords: Sudan, Groundwater, Policy, Water Resources, Management
Analysis of shear-wave splitting to infer the seismic anisotropy of the lithosphere-asthenosphere system – inversion ambiguities, automatization, and machine-learning approaches
Authors: Rümpker Georg , Kaviani Ayoub , Link Frederik , Reiss Miriam , Chakraborty Megha , Faber Johannes , Köhler Jonas , Srivastava Nishtha
Published: February 2023

Seismic anisotropy provides a unique link between directly observable surface structures and the more elusive dynamic processes in the mantle below. The ability to infer the vertically- and laterally-varying anisotropic structures is of great significance for the geodynamic interpretation of surface-recorded waveform effects.In the first part of this presentation, we assess the capabilities of different observables for the inversion XKS phases to uniquely resolve the anisotropic structure of the upper mantle. For this purpose, we perform full-waveform calculations for simple models of upper-mantle anisotropy. In addition to waveforms, we consider the effects on apparent splitting parameters and splitting intensity. The results show that, generally, it is not possible to fully constrain the anisotropic parameters of a given model, even if complete waveforms are considered. We also discuss advantages and disadvantages of using the different observables.Recent technological advances have prompted implementations of large-scale seismic experiments producing huge amounts of seismic data. Standard processing procedures, thus, require automatization to facilitate fast and objective data processing. This also applies to the analysis of shear-wave splitting. A recent extension of the SplitRacer software code allows for an automatization of the analysis by choosing a time window based on spectral analyses and by categorization of results based on different splitting methods.Finally, we will present new results from the application of Neural Networks to the analysis of shear-wave splitting. Our initial approach involves training based on synthetic data and deconvolution of the real waveforms. Current limitations and possibilities for extension will be discussed.
Quantifying localized carbon dioxide emissions from space: the CO2Image mission
Authors: Feist Dietrich G. , Roiger Anke , Marshall Julia , Gottschaldt Klaus-Dirk , Reum Friedemann , Lichtenberg Günter , Baumgartner Andreas , Hochstaffl Philipp , Köhler Claas , Schreier Franz , Krutz David , Paproth Carsten , Pohl Andreas , Sebastian Ilse , Walter Ingo , Butz André
Published: February 2023

Space-based observations of carbon dioxide (CO2) are the backbone of the global and national-scale carbon monitoring systems that are currently being developed to support and verify greenhouse gas emission reduction measures. Current and planned public satellite missions, such as GOSAT 1+2, OCO 1-3 and the European Union's Anthropogenic Carbon Dioxide Monitoring mission CO2M, aim at constraining national and regional-scale emissions down to scales of urban agglomerations and large point sources with emissions in excess of ~10 MtCO2/year.We report on the DLR demonstrator mission CO2Image, which is planned for launch in 2026. The mission will complement the suite of planned CO2 sensors by zooming in on facility-scale emissions, detecting and quantifying emissions from point sources as small as 1 MtCO2/year. A fleet of CO2Image sensors would be able to monitor roughly 90% of the CO2 emissions from coal-fired power plants worldwide. The key feature of the mission is a target region approach, measuring approximately 75 tiles of size ~50 x 50 km2 per day at a resolution of 50 x 50 m2. Thus, CO2Image will be able to resolve plumes from individual localized sources, essentially providing super-resolution nests for survey missions such as CO2M. In addition, the choice of the spectral window will allow the detection of point sources of methane as small as 100 kg CH4/hr will also be possible.We present the instrument concept, a spaceborne push-broom imaging grating spectrometer developed and built by DLR. It will measure spectra of reflected solar radiation in the short wave infrared spectral band around 2000 nm. It relies on a comparatively compact design with a single spectral window and a spectral resolution of approximately ~1 nm. This spectral resolution has been optimized for greenhouse gas retrieval and should provide improved precision and accuracy compared to hyperspectral sensors with comparable spatial resolution. We will further discuss the overall mission concept in terms of the sampling strategy, outlining how target scenes will be selected. As a publicly-funded mission, CO2Image will provide public, transparent information about anthropogenic greenhouse gas emissions from space.
Transformative Adaptation through Nature-Based Solutions: A Comparative Case Study Analysis in China, Italy and Germany
Authors: Scolobig Anna , Linnerooth-Bayer JoAnne , Pelling Mark , Martin Juliette , Deubelli Teresa , Liu Wei , Oen Amy
Published: February 2023

This presentation explores how claims for transformative adaptation toward more equitable and sustainable societies can be assessed. We build on a theoretical framework describing transformative adaptation as it manifests across four core elements of the public-sector adaptation lifecycle: vision, planning, institutional frameworks, and interventions. For each element, we identify characteristics that can help track adaptation as transformative. Our purpose is to identify how governance systems can constrain or support transformative choices and thus enable targeted interventions. We demonstrate and test the usefulness of the framework with reference to three case studies of nature-based solutions (NBS): river restoration (Germany), forest conservation (China), and landslide risk reduction (Italy). Building on a desktop study and open-ended interviews, our analysis adds evidence to the view that transformation is not an abrupt system change, but a dynamic complex process that evolves over time. While each of the NBS cases fails to fulfill all the transformation characteristics, there are important transformative elements in their visions, planning, and interventions. There is a deficit, however, in the transformation of institutional frameworks. The cases show institutional commonalities in multi-scale and cross- sectoral (polycentric) collaboration as well as innovative processes for inclusive stakeholder engagement; yet, these arrangements are ad hoc, short-term, dependent on local champions, and lacking the permanency needed for upscaling. For the public sector, this result highlights the potential for establishing cross-competing priorities among agencies, cross-sectoral formal mechanisms, new dedicated institutions, as well as programmatic and regulatory mainstreaming.