bluuebunny/crossref_metadata_2025 huggingface dataset:
A catalog of volcanic earthquake swarms in the United States: comparative analysis and use in eruption forecasting
Authors: Pesicek Jeremy , Prejean Stephanie
Published: February 2023

Swarms of earthquakes are often associated with eruptive processes, but many swarms occur near volcanoes that are not easily associated with eruptions, complicating their use in eruption forecasting.  In some cases, swarms may be caused by hydrothermal processes and can be considered as part of a volcano’s normal background seismic activity. Other swarms near volcanoes may be considered purely tectonic in origin, or some combination of tectonic, magmatic, and hydrothermal processes. Distinguishing driving processes for a volcanic swarm is often difficult using seismic data alone and yet seismic data may be the only monitoring stream available at many volcanoes.  Even when other monitoring data are available, seismic unrest often manifests itself first in the run-up process to an eruption.  Thus, tools that help distinguish whether a swarm is magmatic or not are desirable for observatories to improve forecasting efforts.Determining when an eruption will follow a swarm is non-trivial, even if a swarm can be confidently linked to a magma intrusion.  Statistical comparison of an ongoing swarm to prior swarms at the volcano or at other volcanoes provides baseline probabilities for forecasting efforts and may reveal patterns in precursory activity in general. Swarms are often easy to visually identify in an earthquake catalog, but as no standard approach exists to consistently define and detect swarms across time and space, it is difficult to statistically compare them. At individual volcanoes, temporal changes in monitoring networks present challenges, while other factors, such as varying rates of background seismicity, complicate inter-volcano swarm comparisons.To address some of these challenges, we have created a catalog of earthquake swarms covering 62 eruptions at 79 active volcanoes in the United States. The catalog balances consistency in methodology with the inherent variations between and among the volcanoes and their monitoring networks and is calibrated such that only concerning swarms, significantly above background levels, are retained.  We compute a suite of statistical attributes for each swarm and compare these attributes among various subgroups of swarms and volcanoes. Overall, we find that ~25% of the swarms in the catalog are associated with eruptions but only ~10% began prior to the eruption. In addition, though ~35% of eruptions are associated with swarms, only ~20% of eruptions have swarms that began prior to the eruption.  The eruptive and non-eruptive swarms show significant differences in evolution of moment release and event rate, but these differences vary depending on the types of volcanoes and eruptions considered. When tailored to the specifics of an ongoing swarm, analog swarm comparisons may help decipher driving process and likelihood of eruption.    
Paleozoic Metamorphic History of Strandja Massif, NW Turkey
Authors: Paksoy Nefise , Paksoy Yunus Can , Topuz Gültekin
Published: February 2023

The Strandja Massif is a NW-SE trending, extensive polymetamorphic belt (300 km length and 100 km width) cropping out in the NW Turkey and SE Bulgaria. The last metamorphism is of upper greenschist- to lower amphibolite-facies and occurred during the Late Jurassic-Early Cretaceous. The massif constitutes a Paleozoic metamorphic basement cut by intrusions of various ages and overlain by a Mesozoic metasedimentary cover. The Mesozoic cover displays monotonous deformation and metamorphic history whereas the Paleozoic basement shows complex structural fabric and metamorphism. Age and metamorphic conditions of the Late Jurassic- Early Cretaceous metamorphism is well-constrained while the timing and P-T conditions of earlier metamorphism are hardly known. In this study, we deal with the timing and metamorphic conditions of the earlier metamorphism.For this purpose, we studied the northwest part of the Strandja Massif where basement rocks are widely exposed. The basement rocks consist of biotite gneiss, metagranite, biotite garnet gneiss, amphibolite, quartzo-feldspathic schist, and metaperidotite. The most suitable rock type for the determination of P-T conditions and timing of the Paleozoic metamorphism is biotite garnet gneiss.The biotite garnet gneiss is characterized by the development of mm- to 5 cm- thick leucosomes. The biotite garnet gneiss contains mineral assemblages involving biotite, garnet, staurolite, plagioclase, quartz, muscovite, and chlorite. Idioblastic garnet porphyroblasts, up to 1 cm across, contain inclusion- trails that define a curved internal foliation. Matrix foliation displays continuity with the internal foliation in the garnet, pointing to the syntectonic nature of the porphyroblast. A weak foliation which is defined by the parallel alignment of mainly muscovite crosscuts the main foliation. Based on these textural characteristics we infer that the migmatization and main foliation were developed probably at upper amphibolite facies conditions during the Paleozoic, and the relatively late weak foliation at upper greenschist- lower amphibolite- facies conditions during Late Jurassic-Early Cretaceous.To constrain the timing and metamorphic conditions of the earlier and later metamorphism we separated monazite and rutile from biotite garnet gneiss and titanite from the amphibolite. Electron microprobe work and U-Pb dating on monazite, rutile, and titanite are in progress.
Mechanistic patterns of land hydroclimate changes in a changing climate
Authors: Duan Suqin , Findell Kirsten , Fueglistaler Stephan
Published: February 2023

Climate model predictions of land hydroclimate changes show large geographic heterogeneity, and differences between models are large. We introduce a new process-oriented phase space that reduces the dimensionality of the problem but preserves (and emphasizes) the mechanistic relations between variables. This transform from geographical space to climatological aridity index (AI) and daily soil moisture (SM) percentiles allows for interpretation of local, daily mechanistic relations between the key hydroclimatic variables in the context of time-mean and/or global-mean energetic constraints and the wet-get-wetter/dry-get-drier paradigm. Focusing on the tropics (30S-30N), we show that simulations from 16 different CMIP models exhibit coherent patterns of change in the AI/SM phase space that are aligned with the established soil-moisture/evapotranspiration regimes. Results indicate the need to introduce an active-rain regime as a special case of the energy-limited regime. In response to CO2-induced warming, rainfall only increases in this regime, and this temporal rainfall repartitioning is reflected in an overall decrease in soil moisture. Consequently, the regimes where SM constrains evapotranspiration become more frequently occupied, and hydroclimatic changes align with the position of the critical soil moisture value in the AI/SM phase space. Analysis of land hydroclimate changes in CMIP6 historical simulations in the AI/SM phase space reveal the very different impact of CO2 forcing and aerosol forcing. CESM2 Single Forcing Large Ensemble Experiments are used to understand their roles.
The development and application of a mechanistic photosynthetic-stomatal conductance canopy model (DO3SE-crop)
Authors: Pande Pritha , Bland Sam , Booth Nathan , Cook Jo , Emberson Lisa
Published: February 2023

The impact of elevated ozone concentration on crop yield, like wheat, plays a significant role yet is poorly studied in Asian countries like China and India. We have developed, calibrated, and tested a mechanistic photosynthetic-stomatal conductance canopy model (DO3SE-crop) with an integrated ozone module (Anet-gsto+O3) for the region of Xiaoji, China. The key component of the model development involves phenology, leaf scale processes, leaf-to-canopy upscaling, and carbon allocation. The calibrated model for Xiaoji simulated the difference in yield losses for ambient and elevated ozone treatments for the years 2008 for four cultivars (Y2, Y15, Y16, Y19), ranging from 21-24%, compared with the observed dataset, giving R2 of 0.74 and RMSE of 0.003. The model was tested for 2009 and gave yield losses of 24-27%, with R2 of 0.60 and RMSE of 0.12, against the observed dataset. Further, our findings suggest that the difference in yield loss is due to the early decline in carbon assimilation in elevated treatment.This happens because of the early senescence in elevated treatment, which brings leaf senescence forward by 9-11 days.
Evaluation of four hydrological models to simulate daily streamflow time series in a tropical river basin of Brazil
Authors: Ávila Leandro , Silveira Reinaldo , Campos André , Rogiski Nathalli , Freitas Camila , Aver Cássia , Fan Fernando
Published: February 2023

The Electric Energy Company of Parana (COPEL GeT), the Meteorological System of Parana (SIMEPAR) and RHAMA Consulting company are undertaking the research project PD-6491- 0503/2018 for the development of a hydrometeorological seasonal forecasting for Brazilian reservoirs. The project, sponsored by the Brazilian Electricity Regulatory Agency (ANEEL) under its research and development program, aims the forecasting of streamflow, at temporal scales ranging from 1 to 270 days, at hydro power enterprises, which are integrated by the National Power System Operator (ONS) through its Interconnected System (SIN). With the aim of implement a seasonal forecasting system using different hydrological modeling approaches, it is necessary first to validate the use of different hydrological models during the calibration and validation stages. This work evaluates the performance of four conceptual hydrological models to represent daily streamflow regimes at four hydropower plants located in the Teles Pires river basin (Brazil). The adopted models included the GR4J, HYMOD, HBV, and the SMAP. The calibration of the parameters for each hydrological model was performed using the SCE-UA method and a triangular weighting function was adopted for routing the hydrograph between sub-watersheds. The evaluation of each model was elaborated by the comparison of the observed and simulated streamflow time series during the calibration (2010-2016) and the validation period (2016-2019) using deterministic metrics and statistical tests. A post-processing procedure based on the quantile-quantile method was applied in order to correct the simulated data and reduce the bias with respect the observed data. In general, the results show that the SMAP model present a better performance to simulate the daily streamflow regimes at the simulated hydropower plants, with Nash-Sutcliffe coefficient (NSE) greater than 0.65, and NSElog values greater than 0.8. In addition, the bias correct procedure shows a significant improvement in the adjust of the simulated data to represent the periodic streamflow regimes in the selected river basin.
Extracting value from seasonal forecasts for droughts: an approach based on persistence rules.
Authors: Cristina de Oliveira Rafaela , Petry Ingrid , Mainardi Fan Fernando
Published: February 2023

Long-term planning is part of good water resource management. This management takes place according to the needs of society, such as optimizing energy production, providing water for agriculture, supplying industry and guaranteeing urban water supply. The quantification of water resources and their long-term forecast are tools that help with this planning. In this work, we evaluated the ability of seasonal streamflow forecasts to detect droughts periods based on forecast evaluation rules of a Hydrologic Ensemble Prediction System (H-EPS), and compare them with the benchmark Ensemble Streamflow Prediction (ESP). Seasonal forecasts of seven months horizon were generated using the MGB-AS model forced with ECMWF seasonal precipitation forecasts (SEAS5), for basins larger than 1000 square kilometers. The focus of the study were the 153 hydroelectric plants of the Brazilian National Interconnected System (SIN), which affluent flows were studied for the period of 2007 to 2016.  For each plant, drought forecasts were analyzed using the Area Under the Receiver Operating Characteristics curve (AUROC). The drought threshold was defined as the 90th percentile of the flow, using data from 1979 to 2006. Exceedance diagrams were made, where each forecast horizon was represented with the percentage of members that indicated the occurrence of a dry month. Then, contingency tables were set up, considering the drought detection criterion as at least one member indicating drought in the seven horizons and six months with at least 20% of the members indicating drought. The rule was elaborated based on data from the Itaipu power plant (Paraná River) and applied to all plants. Through the results, it was observed that the H-EPS forecasts were more accurate in detecting droughts than the benchmark. In the regional analysis of the results, the rule chosen for Itaipu was also suited for the plants in the southeast region. This may have occurred because these hydroelectric plants rivers present similar hydrological behavior, related to the type of soil, evapotranspiration rates, precipitation, climate and similar relief. Our next steps involve the creation, testing and analysis of more locally and temporally optimized rules, including some that consider only the first months predicted in the analysis.
Comparing 28 global P- and S- wave tomography models by Machine Learning analysis for the interpretation of the Earth’s mantle structures
Authors: Rahimzadeh Bajgiran Moloud , Colli Lorenzo , Wu Jonny
Published: February 2023

Seismic velocity anomalies observed in the mantle can have several origins, the main contributions being anomalies of temperature and composition. The difference between P- and S-wave models has been used to separate thermal and compositional contributions in imaged seismic structures and identify large-scale compositional heterogeneity in the Earth's mantle. According to our two-step Machine Learning (ML) analysis of 28 P- and S-wave global tomographic models, P- and S-models differences are not intrinsic and can be reduced by changing the models in their respective null spaces. Because we find, P- and S-wave images of mantle structure are not necessarily distinct from each other, a purely thermal explanation for seismic structure is sufficient at present; significant mantle compositional heterogeneities do not need to be invoked. In this study, 28 commonly used tomographic models are examined, ranging from ray theory (e.g., UU-P07, MIT-P08) to Born scattering (e.g., DETOX) and full-waveform techniques (e.g., CSEM, GLAD). Combined Varimax Principal Component Analysis is used to reduce the dataset's dimensionality (by 82%) while preserving the relevant information of each tomographic model (94% of the original variance). Reduced-sized models are followed by a hierarchical clustering analysis (HC) using Ward’s method to categorize all the models into a hierarchy of groups based on their similarities. HC divided the set of tomographies into two main clusters: the first cluster, which we named "Pure P-wave", is composed of six P-wave models that only use longitudinal body wave phases (e.g., P, PP, Pdiff); the second cluster "Mixed" includes both P- and S-wave models; P-wave models in this cluster use inversion methods that include inputs from other geophysical and geological data sources, that cause them to be more similar to S-wave models than to pure P-wave models without a significant loss of fitness to P-wave data. Results suggest that the differences between some individual P-wave and S-wave models are smaller than the differences between grouping of models that are only P-wave or S-wave. These variable differences clearly convey that no consistent separation exists between the P- and S-wave models. We have also calculated the Distance Matrices along the Principal Components. Comparing clustering results with Distance Matrices shows that the differences between the "Pure P-wave" and "Mixed" clusters are mainly in the upper mantle. Accordingly, our results indicate that P-wave structures do not need to be very distinct from a thermal interpretation of S-wave structures and support a relatively “Homogenous” mantle.
GHOTI: GOES-R High-cadence Operational Total Irradiance
Authors: Penton Steven , Snow Martin , Beland Stephane , Don Woodraska , Odele Coddington
Published: February 2023

The EXIS (Extreme ultraviolet and X-ray Irradiance Sensors) detectors on the GOES-R spacecraft (GOES-16, GOES-17 & GOES-18) use quad-diode Sun Positioning Sensors (SPS) to maintain precision pointing. The 4 Hz quad-diode signal is high-precision and we attempt to use this signal as a high-cadence proxy for Total Solar Irradiance (TSI) and use the MgII index + NRLSS2 models to predict high-cadence spectra. The quad-diode signal must be calibrated for spacecraft velocity (a 1AU correction), instrument temperature, and diode degradation with usage. In the 2nd year of this 3-year project, we report the progress of these calibrations and our efforts toward defining our TSI proxy and high-cadence spectral data products.
Monitoring lake ice with acoustic sensors
Authors: Wetter Christoph , Schmelzbach Cédric , Stähler Simon C.
Published: February 2023

Monitoring of the thickness and elastic parameters of floating ice on lakes and the sea is of interest in understanding the climate change impact on Alpine and Arctic environments, assessing ice safety for recreational and engineering purposes, studying ice shelves as well as exploring possibilities for the future exploration of the icy crusts of ocean worlds in our solar system. A multitude of geophysical methods exist today to monitor sea and lake ice thickness as well as elastic parameters. Mostly, seismic and radar measurements are used. Both methods have in common that they come with significant logistical effort and expensive equipment. In this study, we present a novel low cost approach using acoustic sensors for ice monitoring.We explored the possibility of using microphones deployed on frozen lakes in the Swiss Alps to monitor the lake ice-thickness using acoustic signals originating from frequently occurring ice quakes. Data were obtained during a three-month-long field campaign at Lake St. Moritz in Switzerland in winter 2021/2022. Three microphone stations were placed on the lake in addition to five conventional seismometers. These seismometers were used to compare the acoustic signals with the seismic ice quake recordings. Additionally, also active-source experiments were conducted using hammer strokes as source, which were used to constrain elastic parameters of the ice.The acoustic recordings of ice quakes allowed us to exploit the unique characteristics of so-called air-coupled waves to determine time-dependent ice thickness curves of Lake St. Moritz for winter 2021/2022 using acoustic data only. Furthermore, the acoustic data allowed us to gain new insights into the ice/air coupling of seismic waves in ice. 
Ongoing experiences in establishing and maintaining a grass-roots science outreach initiative; the s-Ink.org graphics repository
Authors: Shephard Grace E. , Crameri Fabio , Straume Eivind O.
Published: February 2023

One of the challenges to establishing and maintaining momentum for community-driven science communication efforts is engaging participation from the wider scientific community. Launched in early 2022, the s-Ink project (www.s-Ink.org) aims to make high-quality (geo)scientific figures freely available via an accessible online platform. The platform hosts figures that can be searched and downloaded by the entire community, including students, researchers, teachers, the media, and the general public. Hosted content is intentionally broad in nature, and can include data visualisations, animations, artistic impressions, icons, templates, and more. Guidelines for generating accessible, eye-pleasing, modifiable, and scientifically-effective graphics are provided. As such, it is envisaged that the initiative will be of direct use to the entire geo(science) community; somewhat of a holy grail of science communication. Importantly, all content on s-Ink.org has metadata and is available via a Creative Commons licence, so those who create the images (and the sources that they are based on) will receive credit.s-Ink.org is currently coordinated by three scientists, working on a volunteer-based approach with non-permanent contracts (one a free-lancer, two with the backing of employers). In order to make the community aware of the resource and to increase the number and breadth of content hosted, we have actively pursued several avenues since launch. These include establishing a social media account, running free graphics short-courses and providing graphic-specific feedback, applying for small funding opportunities (to run short-courses and for gift cards to compensate students, where applicable, such as from the Norwegian iEarth consortium), directly inviting creators, presenting dedicated abstracts at conferences (such as at EGU), spreading the word via mailing lists and through colleagues and networks, and mentioning the resource during invited presentations (e.g. by using graphics). We have also written a pre-print that has been posted on the EarthArXiv server (Crameri et al., 2022, https://doi.org/10.31223/X51P78) with more details. To-date, there are nearly 200 individual graphics available from 13 contributing creators. However, this is far fewer than the number of course students (over 50 to-date) and reach that we aimed for and envisaged at launch. In this presentation, we will present some of the lessons learned to-date from our experience, present some of the access statistics (e.g. the latest website traffic and figure downloads). We wish to engage in a discussion about other small-scale science outreach initiatives, and invite feedback about how best to continue our initiative.
The stability of an asymmetric slice of the Gulf Stream
Authors: Poulin Francis
Published: February 2023

The Gulf Stream plays an important role in the meridional overturning circulation in the North Atlantic, one of the primary mechanism by which the warm, salty water can move from low to high latitudes. It also provides closure to the North Atlantic subtropical gyre circulation as a western boundary current and makes Western European countries much warmer by transporting warm water across the ocean.Observational data of the Gulf Stream (along the Oleander line, between New Jersey and Bermuda) has found that its stream-wise velocity skews to the right with increasing depth. This has motivated our development of an idealized model of a laterally skewed Gulf Stream jet that is surface trapped overlying a flat bottom. The nonlinear evolution of this unstable asymmetric jet is investigated using the Oceananigans.jl library for multiple values of a skewness parameter. The results show that the maximum growth rate has a nonlinear dependency on the skewness parameter, though weak and strong skew tend to be stabilizing and destabilizing, respectively. 
Analyzing the September 5, 2022, CME from a Space Weather perspective: Was this a “Carrington-type” event?
Authors: Paouris Evangelos , Kouloumvakos Athanasios , Vourlidas Angelos , Papaioannou Athanasios
Published: February 2023

The Coronal Mass Ejection of September 5, 2022, was the most extreme CME event ever observed and measured in-situ by spacecraft inside the corona (0.06 AU for Parker Solar Probe) and from multi-viewpoints ranging from 0.71 AU (Solar Orbiter) to ~1.0 AU (STEREO-A and SOHO). In this work, we evaluate the space weather significance of this event by examining the source region characteristics and its evolution as a function of time via a magnetic complexity index. We also examine the kinematics and energetics of the associated CME. It was a very fast and massive event, with a speed greater than 2200 km/s, and a mass of 2×1016 grams. These characteristics place this event in the top 1% of all the CMEs observed by SOHO/LASCO since 1996. It is therefore natural to ask “what if this CME was an Earth-directed one?”.To answer this question, we put the CME and flare properties in the context of similar previous extreme events (the July 23, 2012, and March 7, 2012 eruptions) including the solar energetic particle (SEP) event characteristics. We find that, if this event was magnetically well-connected to Earth, it could have resulted in a ground level enhancement (GLE) event. We estimate the transit time and likely Dst values if this were an Earth-directed event.
Paleobathymetry reconstructions during the Mesozoic and uncertainties in oceanic gateway evolution
Authors: Wright Nicky , Seton Maria , Nanfito Aleece , Atwood Nick , Müller Dietmar
Published: February 2023

The reconstruction of paleobathymetry, in particular the evolution of oceanic gateways, has important implications for paleo-ocean circulation, paleoclimate, as well as biotic and faunal exchanges. During the past ~250 million years there have been major changes in paleobathymetry and oceanic gateways associated with the breakup of the Pangaea supercontinent, including the development of the North and South Atlantic ocean basins and the Central Atlantic seaway. Considerable research effort has been invested into better understanding the global evolution of paleobathymetry and oceanic gateways during the Cenozoic, but there remain large uncertainties about the timing of opening, closure, and physiographic evolution of Mesozoic oceanic gateways and seaways.Here, we present new paleobathymetry reconstructions based on a recent global plate tectonic model (Müller et al., 2019) spanning the Triassic (~250 Ma) to the present. We reconstruct presently-preserved oceanic crust using new functionality developed in pybacktrack v1.4, a python module for backstripping and reconstructing paleobathymetry. For present-day submerged continental crust we use pybacktrack to reconstruct paleobathymetry based on its rifting and deformation history and assuming a single lithology for the progressive decompaction of sediments. In regions where ancient seafloor is now subducted, we use an established approach of synthetically reconstructing paleobathymetry based on the age-area distribution of oceanic crust (‘age grids’) convolved with an age-depth relationship to reconstruct basement depths followed by modelling effects from sediment thickness and seafloor volcanism including large igneous provinces. Our methodology additionally allows for alternative plate tectonic models (and/or absolute reference frames) to be integrated into reconstructions of paleobathymetry. Further, we use our new paleobathymetry reconstructions to explore the formation and evolution of pre-Cenozoic oceanic gateways. We find significant differences in the development and physiography of Mesozoic oceanic gateways and seaways in our new reconstructions compared to a widely used paleogeographic model, which has major implications for paleoceanographic models and interpretations of paleoclimate proxies.
Analytical Hierarchy Process for Mass Moviments Susceptibility Mapping in Fernão Velho, Maceió, Northeast Brazil
Authors: Soares Lima Thyago Anthony , de Oliveira Filho Antonio Rodrigues
Published: February 2023

Mass movements result in great loss of life and property. This damage can be mitigated if the cause and effect relationships of the events are known. In this study, we use the analytical hierarchy process methods (AHP) to produce susceptibility to mass movement in the neighborhood of Fernão Velho, in the city of Maceió, capital of the state of Alagoas, northeastern Brazil . The study was conducted using remote sensing data, field surveys, and geographic information system (GIS) tools. That influence the occurrence of mass movement, such as elevation, slope aspect, slope gradient, density of buildings/cuts and embankments, lithology, distance from the lineament, soil, precipitation, land use/land cover (LULC) and influence of the railway line. Then the susceptibility to mass movement was established based on the assigned weight and ranking given by the AHP method. The result of the analysis was verified using existing mass movement occurrence sites, where it was obtained through the ROC index, an AUC of 86% , and a confidence interval of 82% , having an accuracy rate of 90% . The map of susceptibility to mass movement obtained is useful for prevention and mitigation of risks to the phenomenon, and proper planning for land use and construction in the future, serving as support for planning and decision-making by the civil protection of the municipality. Keywords: mass moviment susceptibility, analytic hierarchy process, GIS, remote sensing
Toward a glacier retreat driven redistribution of water resources
Authors: Baraer Michel , Mark Bryan , McKenzie Jeff
Published: February 2023

Assessments of glacier retreat impacts on water resources are often carried out using hydrological models calibrated using stream discharge time series. Because long-term discharge measurements are scarce in different regions of the world, models’ outcomes are analyzed assuming implicitly that stream discharge evolution projections at the outlet of a watershed affect the entire drainage area following a uniform pattern. In the present study, building on the learnings from the peak water analysis we performed in 2012, we explore the heterogeneity in Rio Santa sub-watersheds responses to deglaciation. The future of water resources at each watershed is projected by applying the peak water model with the latest glacier area estimations. The resulting map of the projected water availability across the Rio Santa watershed is then overlayed with previous works and literature-based water quality and demand maps.Results show that, while glaciers are losing their hydrological influence across the Cordillera Blanca, gaps open between water availability and demand for water at different levels of the watershed. Moreover, the dry season share of polluted sub-watersheds into the Rio Santa discharge increasing due to glacier retreat, water quality evolution will add up to the challenge of sharing an already scarce resource.Our study suggests that deglaciation in the tropical Andes affects populations and economic activities in a complex, disparate and evolutive way. Therefore, anticipating glaciers retreat redistribution of the water resources requires integrating hydrological, chemical, biological, economic, and sociological water resources aspects in locally grounded studies.   
Open-Source Framework For Earth System Digital Twins Applied to Surface Water Hydrology
Authors: Huang Thomas ,   NASA AIST IDEAS and SCO FloodDAM Teams
Published: February 2023

An Earth System Digital Twin (ESDT) is a dynamic, interactive, digital replica of the state and temporal evolution of Earth systems. It integrates multiple models along with observational data, and connects them with analysis, AI, and visualization tools. Together, these enable users to explore the current state of the Earth system, predict future conditions, and run hypothetical scenarios to understand how the system would evolve under various assumptions. The NASA Advanced Information Systems Technology (AIST) program’s Integrated Digital Earth Analysis System (IDEAS) project partners with the Space for Climate Observatory (SCO) (https://www.spaceclimateobservatory.org/) FloodDAM Digital Twin effort led by CNES to establish an extensible open-source framework to develop digital twins of our physical environment for Earth Science with an initial focus on surface water hydrology in Earth’s rivers and lakes. The joint effort delivers an open-source system architecture with mechanisms for the outputs of one model to feed into others, for driving models with observation data, and for harmonizing observation data and model outputs for analysis. Water resource science is multidisciplinary in nature, and it not only assesses the impact from our changing climate using measurements and modeling, but it also offers opportunities for science-guided, data-driven decision support. The joint effort uses flood prediction and analysis as its primary use case. The work presents a multi-agency joint effort to define and develop a federated Earth System Digital Twin solution between NASA and CNES that powers advanced immersive science and custom user applications for scenario-based analysis.
The influence of high evaporative conditions on peat-forming mosses in the Antarctic Peninsula
Authors: Jones Danielle , Groff Dulcinea , Beilman David
Published: February 2023

Low-elevation coastal ecosystems of the northern Antarctic Peninsula are responding to rapid climate change by expansion of ice-free areas and increased vegetation cover. The record-setting air temperatures during the austral summer of 2020 provided an opportunity to evaluate the sensitivity of peat-forming and carbon accumulating mosses to conditions with high evaporative demand, a departure from the typical wet, cold, and windy conditions of the northern Antarctic Peninsula. Mosses are sensitive to environmental change and have been used as archives of paleoclimate information where few terrestrial records exist. However, it is still unclear how much of an influence increased evaporative demand, source water variation, or microclimate can have on moss leaf cellulose. We collected environmental waters and moss surface samples to explore the influence of microclimate, persistent snowmelt, and evaporation on moss tissue waters and cellulose for two moss species, Chorisodontium aciphyllum and Polytrichum strictum. Using the δ18O isotope values of moss tissue waters and leaf alpha-cellulose from surface samples, we compared the enrichment found in mosses to the enrichment in local water sources.  

δ2H and δ18O isotopes of moss tissue waters ranged from -87 to -23‰ and -10.6 to 0.6‰, respectively, indicating significant enrichment relative to our environmental water samples (δ2H values of -98.3 to -48.7‰ and δ18O values of -12.1 to -5.21‰) and long-term summer precipitation (February, δ2H values of -66.9 ± 15.9‰ and δ18O values of -8.11 ± 2.20‰, Vernadsky Station). Negative correlations between δ18O of moss water and the daily average and maximum relative humidity (on the day of collection) (r = -0.44; p < 0.001 and r = -0.62; p < 0.001, respectively) suggest that conditions resulting in high evaporative demand may have a dominant effect and imprint on the δ18O of moss cellulose. We found no relationship between δ13C values of alpha-cellulose, which reflect changes in CO2 diffusivity with moisture conditions, and microclimate variables or average temperature and relative humidity on the day of sample collection. This is possibly the result of discrepancies between peak growth and seasonal peaks in cumulative evaporation leading the tissues to incorporate multiple seasons. The isotope values of moss waters likely reflect the anomalously warm summer on the Antarctic Peninsula, as indicated by the divergence from moss water lines published in non-record-setting summers. Although the δ18O values of moss tissue waters are a proxy for the composition of δ18O values of summer precipitation, it is critical to consider the imprint of high evaporative conditions, in addition to summer precipitation composition, when reconstructing past environmental conditions using cellulose from peat archives. 
Drivers and rarity of the strong 1940s westerly wind event in the Amundsen Sea, West Antarctica
Authors: O'Connor Gemma , Holland Paul , Steig Eric , Dutrieux Pierre , Hakim Greg
Published: February 2023

Ice loss in the Amundsen Sea Embayment is occurring primarily via exposure to warm ocean water, which varies in response to local wind variability. There is evidence that glacier retreat in this region was initiated in the mid-20th century, however the perturbation that may have triggered retreat remains unknown, leaving the climatic mechanisms driving retreat highly uncertain. A leading hypothesis is that a large atmospheric circulation anomaly in the Amundsen Sea occurred in the 1940s, driving a strong oceanic ice-shelf melting perturbation. However, the characteristics and drivers of this 1940s event remain poorly constrained, and the expected occurrence of such events in a natural climate has not yet been evaluated. We investigate this hypothesis using paleoclimate reconstructions and climate model simulations. The reconstructions show that a large multi-year westerly wind anomaly occurred from ~1938-1942, likely as a combined response to the very large El Niño event from 1940-1942 and variability sourced from outside the tropical Pacific starting years earlier. In climate model simulations we find evidence that events of similar magnitude and duration are unusual but may have occurred tens to hundreds of times throughout the Holocene. Our results suggest that the strong westerly event in the 1940s is unlikely to be exceptional enough to initiate glacier retreat on its own; naturally driven climatic/oceanic trends preceding the event or perhaps anthropogenically driven trends following the event are needed to explain retreat. Our analyses provide novel constraints on the significance of the 1940s westerly event in the Amundsen Sea and highlight outstanding uncertainties in our understanding of the mechanisms driving glacier retreat. 
Dynamics of trace elements during seawater intrusion in a sedimentary aquifer of western Mexico
Authors: Mora Abrahan , Mahlknecht Jürgen
Published: February 2023

This study shows the dynamics of several trace elements in groundwater of a coastal sedimentary aquifer of western Mexico affected by seawater intrusion. The results of the chemical analyses performed in groundwater indicated that the elements Ba, Sr, Li, Fe, Co, V, Se, and Re are mobilized from the aquifer sediments to the aqueous phase during seawater intrusion, whereas Rb is removed from solution during salinization. Overall, the mobilization/removal of these elements may be due to processes such as cation exchange, the increase of the ionic strength due to increasing salinity and the weathering of biogenic carbonates in an oxidizing environment. Other elements such as Mo, Ni, Cr, Ta, and W displayed low or no mobilization during the seawater intrusion. This may indicate that dissolution of biogenic carbonates is not their main sources and that these elements are not affected by the ionic strength caused by groundwater salinization. Finally, other elements such as As, U, Ge, Sb, Cu, and Mn displayed an undefined tendency, showing concentrations above and around the theoretical seawater mixing line. These elements may be likely affected by other processes rather than seawater intrusion, which may explain their undefined tendency during groundwater salinization. In general, geochemical processes such as carbonate/sulfate complexation (in the case of U), organic matter complexation (in the case of Cu), metalloid co-occurrence (As, Ge, and Sb), and redox processes (in the case of As and Mn) may play a key role in determining the concentration levels of these elements in this coastal groundwater system affected by seawater-freshwater mixing.
Not all basins are created equal: Lithospheric-scale analogue experiments of selective basin inversion
Authors: Samsu Anindita , Gorczyk Weronika , Amirpoorsaeed Fatemeh , Schmid Timothy , Morton Eleanor , Betts Peter , Cruden Alexander
Published: February 2023

The inversion of rift basins is commonly associated with the reactivation of normal, basin-bounding faults or shear zones. Analogue models have shown how the reverse reactivation of these pre-existing structures facilitates the uplift of a basin’s sedimentary infill. However, few of these models examine the viscous processes occurring beneath the brittle crust, which may or may not drive basin inversion. In our study, we use lithospheric-scale analogue experiments of orthogonal extension followed by shortening to simulate rifting followed by inversion and orogenesis. Here we explore how the flow behaviours of ductile layers underneath rift basins promote or suppress basin inversion.In our experiments, we simulate rifting by extending a multi-layer, brittle-ductile lithosphere which floats on a fluid asthenosphere, creating a system of distributed basins. This extension is followed by shortening of the model, during which strain is accommodated by the reactivation of basin-bounding faults and folding or upwelling of the ductile layers. These experiments reveal that the rheology of the ductile lower crust and lithospheric mantle, modulated by the imposed bulk strain rate, determine: (1) how rift basins are distributed during extension and (2) whether all or only some of these basins are inverted during shortening. We interpret that this selective basin inversion is related to the superposition of crustal-scale and lithospheric-scale boudinage during the basin-forming extensional phase. Our findings demonstrate that lithospheric-scale analogue models can be a powerful tool for investigating the interaction between brittle and viscous deformation during basin inversion.
Soil and soil-gas surveys for geothermal exploration at Cumbre Vieja volcano, La Palma, Canary Islands
Authors: Martín-Lorenzo Alba , Pérez Nemesio M. , Melián Gladys V. , Rodríguez Fátima , Amonte Cecilia , Asensio-Ramos María , Hernández Pedro A. , Padrón Eleazar
Published: February 2023

The most common types of survey in known geothermal areas are water and gas sampling of natural discharges. However, where wáter and gas discharge features are few and where the extent of the field is not known, soil and soil-gas surveys can prove useful. These surveys can identify areas in a field that are permeable and potential upflow or boiling zones. They can also outline the boundaries of a geothermal system, often in conjunction with geophysical surveys to provide more comprehensive understanding, especially when geophysical data is difficult to interpret. For all of the above, a soil and soil-gas survey for geothermal exploration had been carried out at Cumbre Vieja volcano that is characterized by neither having visible manifestations of volcanic gases nor zones of hydrothermal alteration on its surface. We have divided the soil and soil-gas survey for geotermal exploration into four categories based on the number of sampling sites per square kilometer: 1) Regional exploration survey (1 sampling site/km2), 2) Regular exploration survey (about 5 sample sites/km2), 3) Detailed I exploration survey (between 10 and 100 sampling sites/km2) and 4) Detailed II exploration survey (more than 500 sampling sites/km2). We have classified our soil and soil-gas survey for geothermal exploration at Cumbre Vieja volcano as a regular exploration survey due to the fact that 1200 observation or measurement points were selected for its 220 km2 area, resulting in approximately 5.5 sampling sites per km2. Similar soil gas surveys had been performed in other study áreas of the Canarian archipelago (Rodríguez et al. 2021). At every sampling site, we performed in-situ measurements of soil CO2 efflux and 222Rn activity in the soil gas atmosphere. In addition, soil gas samples were collected at a depth of 40 cm for further chemical and isotopic analysis in our geochem lab. Simultaneously with the soil gas survey, soil samples were collected from the base of the B Horizon-Subsoil (30–50 cm) which were subsequently dried and sieved (80 mesh) for subsequent leaching in order to analyze those volátiles (Hg0, As, B and NH3) of interest that were fixed in the organic-clay fraction of the soils. Some preliminary results of this soil and soil-gas survey for geothermal exploration at Cumbre Vieja are presented.Rodríguez F., Pérez N. M., Melián G. V., Padrón E., Hernández P. A., Asensio-Ramos M., Padilla G. D., Barrancos J. and D’Auria L. (2021). Exploration of deep-seated geothermal reservoirs in the Canary Islands by means of soil CO2 degassing surveys. Renewable Energy, https://doi.org/10.1016/j.renene.2020.09.065
Grid resolution, time discretization, boundary condition, and other challenges in coupled surface/subsurface hydrological modeling
Authors: Paniconi Claudio , Lauvernet Claire , Rivard Christine
Published: February 2023

In this study we push the limits of a physics-based detailed model of surface water/groundwater interactions, CATHY, in order to explore numerical issues related to discretization, coupling, and scale effects. Regardless of the spatial scale of the model domain (field, hillslope, catchment, ...), the processes that are simulated by integrated models such as CATHY are characterized by different dynamic time scales across subsystems and thus require appropriate time stepping schemes. Accurate tracking (in a mass balance sense) of complex exchange fluxes is also a challenge. At larger spatial scales, concerns related to aspect ratio and mesh distortion can influence and constrain grid discretization choices. Across the land surface boundary, different options for representing boundary conditions can lead to widely varying model behaviors. Finally, model performance assessments can be highly sensitive to the response variables of interest. We will illustrate some of these challenges via test case simulations of a long (13 km) transect and a small (0.3 ha) hillslope.
Thermodynamic constraints on changes in temperature persistence and variance under climate change
Authors: Thompson David
Published: February 2023

The effects of extreme temperature events depend critically on both the length and amplitude of the events. Here I review numerical evidence from a range of climate models - including complex Earth System Models and highly simplified aquaplanet models - that indicates robust changes in both temperature persistence and variance under climate change. The most robust changes are found over ocean areas and appear to arise from fundamental thermodynamic constraints on atmospheric water vapor concentrations, the moist atmospheric lapse rate, and longwave radiative cooling. It is argued that such constraints will drive robust changes in the persistence and amplitude of temperature variability over the next century that will be superposed on any other changes due to, say, land-surface processes or variations in the ENSO phenomenom.
Monitoring and understanding upper atmospheric long-term cooling
Authors: Zhang Shun-Rong , Wang Wenbin , Aa Ercha , Erickson Phil , Qian Liying , Goncharenko Larisa
Published: February 2023

Atmospheric climate change is characterized by global warming above the Earth’s surface associated with the increase of the greenhouse gas population since the start of the industrial era. In the upper atmosphere where both neutral and plasma gases are subject to substantial variability due to space and terrestrial weather, including low atmospheric forcing. Direct and long-term ionospheric observations with the incoherent scatter radar (ISR) technique provide an efficient way to quantify and understand the variation trend of the thermal status in the upper atmosphere. Since 2008, the ISRs have been providing some of the key evidence for the cooling in the ionosphere and thermosphere, particularly, its altitude dependence above 100 km. This cooling was increasing as a function of height and was initially interpreted as a greenhouse gas effect in the upper atmosphere which was also observed in satellite drag observations, however, almost all the ISR results suggested that the cooling appeared substantially large and therefore additional cooling processes beyond the greenhouse gases as a thermospheric cooling agent are needed. These include potential wave activity changes arising from climate change as well as secular changes in Earth’s main magnetic field. In this presentation, we provide an updated analysis of ISR-measured trends and discuss some progresses in understanding these results.