bluuebunny/crossref_metadata_2025 huggingface dataset:
Establishing streamflow drought characteristics in an inter-Andean Mountain catchment
Authors: Sucozhañay Adrian , Célleri Rolando
Published: February 2023

Drought is the most damaging natural phenomena for large areas and populations. Places such as the Andean tropics have not been exempt from the presence of these events. Among these, hydrological droughts play a critical role because streamflow is closely related to the development of the population living in mountains. The study of these droughts has been neglected because, most of the time water availability has exceeded the water demand. However, this has caused a high vulnerability in the region due to the lack of knowledge and preparation for these events. In addition, the intensification of the water cycle due to climate change aggravates the situation. In this context, the objective of this study was to characterize streamflow droughts in an inter-Andean catchment. The study was performed in four near-natural headwater catchments distributed in a nested approach. Catchments are located in the southern Ecuadorian Andes, between 4550 and 2500 m a.s.l. where groundwater contribution is significantly reduced. Between 25 and 44 years of daily streamflow data was used. To identify streamflow droughts, the threshold method was used on a fixed and daily basis. In addition, different threshold levels obtained from the 70th, 80th, 90th, 95th and 98th percentiles of the duration curve were used. From the events identified, the characteristics of duration, magnitude and intensity were calculated. The five percentiles identified a minimum and maximum number of 40 and 670 events, respectively. On the other hand, the fixed threshold detected on average 27% more events compared to the daily threshold. The average duration, magnitude and intensity varied between: 3.2 and 12.85 days; 0.12 and 5.31 mm; and 0.02 and 0.24 mm day-1, respectively. Despite the existence of events with more extreme characteristics, on average, the presence of events of short duration and magnitude prevail. These results are very different compared to those produced in lowlands, where the contribution of groundwater is important. Additionally, the lag between a meteorological and hydrological drought is very small, and therefore other ways to identify droughts should be studied. Results provide insight into the identification and characteristics of streamflow droughts in a poorly studied region such as the Andes. These can help to improve water resource management rules and evaluate water stress scenarios.
Navigating Responsible Water Modeling in the Wake of COVID-19
Authors: Nabavi Ehsan
Published: February 2023

The COVID-19 pandemic has shown the importance of modeling in guiding decision-making for governments and society, and the significant influence that modelers hold, especially during times of crisis. Water modelers may also encounter similar situations where their models are caught up in political debates, shaping people's everyday lives. This paper discusses the cultural and professional norms around water modeling practice that need to be established or revisited in order to make modeling work more responsible, through a review of models developed for COVID-19. It introduces six areas of study for "responsible water modeling" that can advance future theoretical and practical discussions on the topic: (1) building a common appreciation of the concept of responsibility, (2) interactions between science and policy, (3) the influence of boundary judgments on the model's outcome, (4) the politics of uncertainty, (5) stakeholder involvement, and (6) integration and coordinationThe paper suggests that by focusing on these subjects, the fundamental principles and characteristics of responsible modeling can be established in order to address and respond to water challenges while also serving the public good.
Estimated remaining carbon budgets under terrestrial nutrient limitation
Authors: De Sisto Makcim , MacDougall Andrew H.
Published: February 2023

Nutrient limitation is a core regulation on the amount of carbon fixed by terrestrial vegetation. Hence, the addition of nutrients such as nitrogen and phosphorus in land model structures in Earth system models is essential for an accurate representation of the carbon cycle feedback in future climate projections. Thereby, the estimation of the remaining carbon budget is impacted by the regulation of nutrient limitation in terrestrial ecosystems, and yet it is rarely accounted for. Here, we estimate the carbon budget and remaining carbon budget of a nutrient limited Earth system model, using nitrogen and phosphorus cycles to limit vegetation productivity and biomass. We use eight Shared Socioeconomic Pathways scenarios on three distinct model structures: 1) carbon cycle without nutrient limitation, 2) carbon cycle with terrestrial nitrogen limitation and 3) carbon cycle with terrestrial nitrogen and phosphorus limitation. The three model structures were calibrated to historical temperature data, and to capture the uncertainty of the remaining carbon budget, three different climate sensitives were tuned for each model version. Our results show that overall the nutrient limitation reduced the remaining carbon budget for all simulations in comparison with the carbon cycle without nutrient limitation. Between the nitrogen and nitrogen-phosphorus limitation, the latter had the lowest remaining carbon budget. The mean remaining carbon budget from the Shared Socioeconomic Pathways scenarios simulations for the 1.5 °C target in the no nutrient limitation, nitrogen limited and nitrogen-phosphorus limited models obtained were 303±31, 280±40 and 241±28 Pg C respectively. As for the  2 °C target the mean remaining carbon budget were 517±193, 468±175 and 436±163 Pg C for the no nutrient limitation, nitrogen limited and nitrogen-phosphorus limited models respectively. This represents a reduction of 7.5 and 20.1% for the 1.5 °C target and 9.4 and 15.6% for the 2 °C target in the nitrogen and nitrogen-phosphorus limited simulations compared to the no nutrient limitation model. These results show that terrestrial nutrient limitations constitute an important factor to be considered when estimating or interpreting remaining carbon budgets and are an essential uncertainty of carbon budgets in Earth system models.
A new algorithm to separate meteor trail echoes from ionospheric radar scatter
Authors: Ivarsen Magnus , Hussey Glenn , St-Maurice Jean-Pierre , Lozinsky Adam , Galeschuk Draven , Pitzel Brian , McWilliams Kathryn
Published: February 2023

Coherent scatter echoes from meteors entering Earth’s atmosphere and those from the ionospheric E-region overlap: echoes of both types are seen at altitudes between 95 km -105 km. The physical origin of plasma irregularities produced by disintegrating meteors naturally differ from that of ionospheric turbulence, and there is a need to distinguish between the two types of echoes. We present a novel algorithm to automatically sort through arbitrarily large datasets of radar echoes with accurate location data, classifying each echo as either meteoric or ionospheric in origin. The algorithm establishes a definition of clustering, in both time and space. We use data from ICEBEAR 3D, an experimental coherent scatter radar in Saskatchewan, Canada. We discuss the two classes of scatter echoes, and present statistical results from 2020, 2021. In future experiments, our proposed algorithm can be applied to both coherent and incoherent radar scatter, provided they come with 3D location information.
World Digital Magnetic Anomaly Map (WDMAM) v.2.1 and the magnetic signature of geological provinces
Authors: Dyment Jerome , Choi Yujin , Lesur Vincent , Garcia Reyes Andreina , Catalan Manuel , Ishihara Takemi , Litvinova Tamara , Hamoudi Mohamed
Published: February 2023

The World Digital Magnetic Anomaly Map is prepared under the auspices of IAGA and the CGMW (Commission for the Geological Map of the World) of UNESCO. A first version was released in 2007 (Korhonen et al., 2007), and a second one in 2015 (Dyment et al., 2015; Lesur et al., 2016) with the mandate to update the version 2.0 using the same methodology when the availability of new data would make it necessary. The present version 2.1, compiled at 5 km interval, at 5 km altitude above the continents and at sea-level over the oceans, includes new datasets: (1) the complete digital aeromagnetic map of Brasil made available by ANP; (2) an improved version of the aeromagnetic map of Russia prepared by V-SEGEI; (3) the second version of the Antarctic Digital Magnetic Anomaly maP (ADMAP; Golynsky et al., 2018) which results from a remarkable international effort during and after the Second International Polar Year; (4) a new map of the Caribbean plate and Gulf of Mexico resulting from the compilation and re-processing of existing marine and aeromagnetic data in the area (Garcia and Dyment, EPSL, 2021, 2022); (5) the updated Magnetic Anomaly Map of Eastern Asia prepared by the CCOP (MAMEA; Ishihara and Uchida, 2021); and (6) a new marine magnetic anomaly data compilation prepared by T. Ishihara and coworkers. The new map will be presented and its improvements over the previous version discussed.We try to characterize the magnetic signature of the different geological provinces at global scale by comparing WDMAM v.2.1 and the Geological Map of the World (Bouysse et al., 2014, CGMW). The latitudinal and directional dependences of the magnetic anomaly amplitude and shape prevent a direct global comparison. Instead, we examine the distribution of magnetic anomaly amplitudes within the geological provinces continent by continent. We build an histogram of the magnetic anomaly amplitudes for each type of geological province within each studied continent. The histograms resemble normal distributions from which we determine the average amplitude and its standard deviation. The latter reflects how wide is the range of amplitudes in the distribution: a small standard deviation means a narrow distribution and low amplitudes, a large one a wide distribution and high amplitudes. On land, our first investigation suggests that cratons exhibit stronger magnetic anomalies, whereas regions covered by a significant thickness of sediments present weaker anomalies. At sea, large igneous provinces show stronger anomalies, whereas continental platforms and the oceanic crust show similar amplitudes.
Development of a flood events database for the Spanish Mediterranean coast and its application to improve flood risk awareness
Authors: Llasat-Botija Montserrat , Pardo Erika , Esbrí Laura , Marcos Raül , Llasat María Carmen
Published: February 2023

Floods are the natural risk that causes the most damage in Mediterranean coastal areas. In Spain, for instance, more than 60% of disaster compensations correspond to floods. Consequently, it is essential to characterize these phenomena to obtain information that can be useful to improve preparedness and future response by generating effective and efficient adaptation strategies.In the context of the C3RiskMed project, all the flood events that have affected the Spanish Mediterranean coast between 1980 and 2020 have been identified. To this aim, the INUNGAMA flood database (Llasat et al., 2014) has been used as starting point. This database contains all the flood events that have occurred in Catalonia since 1900 and includes hydrometeorological and impact information for each event.  Once this database has been updated until 2020, flood events from the Valencian Community, the Region of Murcia and Mediterranean Andalusia have been searched and classified. This has been achieved by using the Civil Protection Catalog of Historical Floods and other sources such as newspaper archives and reports. This base allows us to characterize the different regions in terms of the impact of events and to identify differences and commonalities to take into account in the design of adaptation measures. It will be also used to identify and characterize compound events.Hence, in this communication we present the update of this database as well as its application as an adaptation tool for Catalonia: the AGORA Flood Observatory. This Observatory consists of an online portal (agora.ub.edu) that contains multiple resources related to floods such as reports of historical events with different sections adjusted to different target audiences (i.e. the general population, schools, expert and/or technical audiences). This observatory also includes the AGORA viewer. This viewer allows interactive consultation of flood events by municipality, county, and river basin, either on a map or in a table (with event details). The observatory also offer technical and pedagogical material about floods for different target groups. The role of this Observatory as an adaptation tool is based on its potential as a decision support and planning tool and its contribution to the improvement of risk awareness of the population. This research has been done in the framework of the C3Riskmed project (MICINN-AEI/PID2020-113638RB-C22) funded by the Spanish Ministry of Science and Innovation and the AGORA project financed by the Water Catalan Agency.Llasat, M.C., Marcos, R., Llasat-Botija, M., et al. (2014). Flash flood evolution in North-Western Mediterranean. Atmospheric Research, 149: 230–243.
Adsorption and Deposition Freezing on Silver Iodide Surface: A Computer Simulation Study
Authors: Roudsari Golnaz , Lbadaoui-Darvas Mária , Nenes Athanasios , Laaksonen Ari
Published: February 2023

Pure liquid water can remain liquid at temperatures as low as -38 oC in the atmosphere. However, ice nucleation can occur at temperatures even higher than -3 oC in the presence atmospheric particles. Cloud ice usually forms as a result of heterogeneous ice nucleation (HIN), where insoluble airborne particles catalyze the freezing process. The current models of HIN are based either on empirical fits to laboratory or field data, or on classical nucleation theory (CNT), which assumes that ice formation occurs in a single step. However, the results of these models can deviate significantly from experimental observations. Molecular simulations can provide an atomistic-level insight into the study of the mechanisms of HIN on different ice nucleating particles. In this study, a combination of molecular dynamics and grand canonical Monte Carlo simulations is used to study the deposition freezing on silver iodide surfaces at various saturation vapor pressures. Silver iodide (AgI) is known for excellent ice nucleating properties and has long been used in rain-seeding applications. The surfaces of ice nucleating particles first adsorb water molecules, forming liquid droplets that fluctuate stochastically until they freeze. Our results reveal atomistic level mechanisms of deposition freezing and further characterize the effects of ice nucleating particles on HIN phenomenon. Based on the simulation trajectories, we found that water molecules adsorb dropletwise on the AgI surfaces in hexagonal arrangements. We also observed simultaneous adsorption of the first and second layers of water molecules and a slightly delayed adsorption of the third layer. Afterward, the multilayer droplets merge into bigger droplets. In addition, our simulation results suggest that ice nucleation initiates after the adsorption of at least four layers of water.        Acknowledgment:This work was supported by the Academy of Finland Flagship ACCC (grant no. 337552) andMEDICEN project (grant no. 345125).
Increased atmospheric dust transport to the Bahamas during early Marine Isotope Stage 8
Authors: Moseley Gina E. , Degenfelder Jonathan W. , Stoll Heather , Wendt Kathleen A. , Kakuk Brian , Edwards R. Lawrence
Published: February 2023

Long-range atmospheric dust transport affects the climate by impacting radiative transfer, cloud formation and the global carbon cycle. Furthermore, dust plays an important role in pedogenesis, whereas Fe-rich dust in particular influences the primary productivity of the ocean. Transport of Saharan dust via the westerlies to the Caribbean is well recorded, even under present conditions, however, its variability over Quaternary glacial-interglacial cycles is less well understood. Here, we present initial investigations into the speleothem record of long-range Saharan dust transport to the Bahamas. A stalagmite collected from -25.6 m below sea level from Abaco Island, Bahamas, macroscopically displays a tripartite structure beginning and ending with opaque crystalline calcite, but with a middle section containing striking insoluble Fe-rich layers several mm thick that alternate with finer opaque layers. The red layers are interpreted to be formed under vadose conditions and not due to precipitation of an Fe-rich crust in an unsaturated mixing zone. U-Th dating reveals that the opaque calcite sections were deposited during Marine Isotope Stage (MIS) 10 and late MIS 8, with the intervening Fe-rich section being deposited during early MIS 8. Dripstone speleothem deposition during MIS 10 and 8 therefore places an upper constraint on relative sea-level elevation of -25.6 m during those glacial periods, with the interglacial MIS 9 hiatus considered to be sea-level controlled. The Fe-rich section indicates atmospheric dust transport to Abaco Island increased during early MIS 8 synchronous with an episode of cooler sea surface temperatures in the sub-tropical Atlantic. On the other hand, the decline in dust transport during late MIS 8 is associated with higher sea surface temperatures.
Evaluating and bridging the flux-variance and surface renewal methods
Authors: Fischer Milan , Katul Gabriel , Noormets Asko , Pozníková Gabriela , Domec Jean-Christophe , Orság Matěj , Trnka Miroslav , King John S.
Published: February 2023

Two micrometeorological methods that utilize high frequency sampling of air temperature were tested against eddy covariance (EC) sensible heat flux (H) measurements at three sites representing agricultural, agro-forestry and forestry systems. The two methods encompass conventional and newly proposed forms of the flux-variance (FV) and surface renewal (SR) schemes.  In terms of measurement setup, the sites represent surface, roughness and roughness to surface transitional layers, respectively. After the selection of the most reliable approaches, regression analyses against EC showed that both methods can estimate H with slopes within ±10 % from unity, and coefficient of determination R2 >0.9 across all three sites. The best performance, of both FV and SR, was at the agricultural field, where the measurements were within the surface layer.  The worst performance occurred in the tall, relatively heterogeneous forest, where the measurements were taken in the roughness sublayer, the depth of which (with its inherent uncertainty) needs to be taken into account in the calculations. In addition to the evaluation of the FV and SR forms, an alternative perspective relating ramp-like structures to the vertical temperature gradients in the surface boundary layer is introduced here. Ramp-like structures carry much of the heat flux and temperature variance, representing opportunities to constrain the coefficients of the two methods. As a corollary, we introduce a novel approach emerging from bridging FV and SR methods that combines information about the coherent structures with the overall variance to obtain heat fluxes in a turbulent atmosphere. The proposed approach yields reliable H estimates without the need for site-specific calibration and instrumentation other than a single fast thermocouple. Acknowledgement: This study was conducted with support of SustES - Adaptation strategies for sustainable ecosystem services and food security under adverse environmental conditions (CZ.02.1.01/0.0/0.0/16_019/0000797) and USDA NIFA-AFRI Sustainable Bioenergy Program, 2011-67009-20089, Loblolly pine-switch grass intercropping for sustainable timber and biofuels production in the Southeastern United States.  Funding for AmeriFlux core site US-NC4 (natural forested wetland) was provided by the USDA NIFA (Multi-agency A.5 Carbon Cycle Science Program) award 2014-67003-22068. Additional funding was provided by the DOE NICCR award 08-SC-NICCR-1072, the USDA Forest Service award 13-JV-11330110-081, and the DOE LBNL award DE-AC02-05CH11231. 
Climate variability as a major forcing of recent Antarctic ice-mass change
Authors: King Matt , Lyu Kewei , Zhang Xuebin
Published: February 2023

Antarctica has been losing ice mass for decades, but its link to large-scale modes of climate forcing is not clear. Shorter-period variability has been partly associated with El Niño Southern Oscillation (ENSO), but a clear connection with the dominant climate mode, the Southern Annular Mode (SAM), is yet to be found. We show that space gravimetric estimates of ice-mass variability over 2002-2021 may be substantially explained by a simple linear relation with detrended, time-integrated SAM and ENSO indices, from the whole ice sheet down to individual drainage basins. Approximately 40% of the ice-mass trend over the GRACE period can be ascribed to increasingly persistent positive SAM forcing which, since the 1940s, is likely due to anthropogenic activity. Similar attribution over 2002-2021 could connect recent ice-sheet change to human activity.
The observed changes in the precipitation regime in Romania – constraints for river restoration
Authors: Constantin (Oprea) Dana Maria , Lüftner Giorgiana Daiana , Ilea Raul Gabriel , Șandor Ionuț Andrei , Ioana-Toroimac Gabriela
Published: February 2023

The success of river restoration depends on precipitation and their hydrological effects. In the context of global warming, an increase in the frequency of extreme events has been observed, with a rapid alternation between periods of excess precipitation with floods and periods of deficit precipitation with drought. Understanding the spatio-temporal variability of the precipitation regime allows to set guidelines for river restoration at a large scale. The main aim of the study is to analyze the variability and observed changes in the precipitation regime in Romania. The research is based on the monthly amounts and maximum precipitation in 24 hours data recorded at 23 meteorological stations, which are part of the Regional Basic Synop Network (RBSN) and belong to the National Meteorological Administration (NMA), for the period 1981 – 2020. Based on these monthly data, the annual, seasonal and semestrial precipitation amounts were calculated. Standardized anomalies and decadal averages were also calculated both annually and for the months January, April, July and October, which are considered typical months from a climatic point of view. The analysis of changes in the precipitation regime is completed by calculating linear trends and statistical significance at annual and seasonal level by applying the Mann-Kendall statistical test. From the analysis of these monthly data of the precipitation amounts, it was found that from January or February to June or July, the monthly precipitation regime shows ascending values, which then gradually decrease until the end of the year. The annual precipitation amounts, at the level of Romania, decrease from west to east as a consequence of oceanic influence’s decrease in the same direction. The variation of the average decennial values of the precipitation amounts indicates increases and decreases from one decade to another, but without significant changes. The trend of average monthly precipitation amounts is predominantly decreasing, but without being statistically significant according to the Mann-Kendall test. In Romania, in the transitional temperate continental climate, the great variability of precipitation in time can be a drawback for self-sustainable river restoration.D.M. (Oprea) Constantin, I.A. Șandor and G. Ioana-Toroimac were supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS - UEFISCDI, project number PN-III-P1-1.1-TE-2021-0600, within PNCDI III.
Roles of diversity and adaptation in the eco-evolutionary responses of biodiverse plant communities to climate change
Authors: Joshi Jaideep , Hofhansl Florian , Singh Shipra , Stocker Benjamin , Brännström Åke , Vignal Toyo , Casagrande Blanco Carolina , Aleixo Izabela , Lapola David , Colin Prentice Iain , Dieckmann Ulf
Published: February 2023

Climate change is projected to cause not only higher mean temperatures but also higher climate variability. Although elevated CO2 concentrations can potentially increase the productivity of some ecosystems, higher temperatures and more frequent droughts may lead to increased respiration and mortality, possibly negating these productivity gains. The capacity of global forests to adjust to climate change depends on their functional diversity and the ecosystem’s adaptive capacity.The Plant-FATE eco-evolutionary model describes vegetation responses to altered environmental conditions, including CO2 concentrations, temperatures, and droughts. It represents functional diversity by modelling species as points in trait space and incorporates ecosystem adaptations at three levels: 1) to model acclimation of plastic traits of individual plants, we leverage the power of eco-evolutionary optimality principles, 2) to model shifts in species composition via demographic changes and species immigration, we implement a trait-size-structured demographic vegetation model, and 3) to model the long-term genetic evolution of species, we have developed new evolutionary theory for trait-size-structured communities.First, we show that with just a few calibrated parameters, the Plant-FATE model accurately predicts the fluxes of CO2 and water, size distributions, and trait distributions for a tropical wet site in the Amazon Forest. Second, we show that under elevated CO2 conditions and in the absence of nutrient limitation, our model predictions are broadly consistent with observations, namely: an increase in leaf area, productivity and biomass, and a decrease in stomatal conductance and photosynthetic capacity. Third, we simulate the calibrated model with hypothetical future drought regimes to investigate three key features of ecosystem responses: 1) the change in species composition and ecosystem functioning in response to altered conditions, 2) the timescales of ecosystem response to new regimes, 3) the influence of functional diversity on the timescale of ecosystem adaptation and its consequences for ecosystem collapse.Our eco-evolutionary vegetation modelling strategy presents a powerful approach to leverage the power of natural selection to simulate ecosystem dynamics under novel conditions that plants may have never experienced before.
INDITEK: A model to understand the emergence of marine biodiversity hotspots in the last 500 million years
Authors: García-Comas Carmen , Cermeño Pedro
Published: February 2023

Life originated in the sea about 4 billion years ago and, for the first 3.5 billion years, it was exclusively microscopic. Something happened early in the Cambrian period that made multicellular life to thrive, giving rise to the spectacular biodiversity that has been this planet's hallmark for the past 500 million years. This staggering increase in diversity has raised a fundamental question among evolutionary ecologists: are there limits to the diversity of life? Some scientists say that global diversity increases to an equilibrium point or saturation level that is determined by the system’s carrying capacity. Alternatively, others claim that biodiversity is well below the saturation level and thus we can ignore the existence of any limit. These contrasting views have been fueled by interpretations of the fossil record which is severely biased in space and time. To theoretically test these contrasting views, we have developed a regional diversification model. In the model, we let 1 genus to diversify everywhere in the global ocean from 500 million years ago until present according to a model of paleogeography that constrains the diversification time and a paleo Earth System model that constrains the diversification rate as a function of seawater temperature and food supply. By externally imposing mass extinctions, we explore how the oceans filled with life. The regional model fits surprisingly well global fossil diversity curves and modern biodiversity distributions. According to the model, the ocean is far from saturation except for in the biodiversity hotspots, regions of extraordinarily high levels of diversity, which evolved under prolonged conditions of Earth system stability and maximum continental fragmentation. The model allows us to recreate many things, such as the history of biodiversity hotspots and the dynamics of the latitudinal biodiversity gradient. 
Improving MISR AOD retrievals over land at medium to high aerosol loadings
Authors: Witek Marcin , Garay Michael , Nelson Robert , Bull Michael , Diner David , Limbacher James , Kahn Ralph
Published: February 2023

Multiangle Imaging SpectroRadiometer (MISR) multi-wavelength and multi-angle observations offer a unique capability for retrieving aerosol optical depth (AOD) and particle properties over most surface types, including land. The excellent quality of MISR aerosol retrievals has been documented in a number of studies. The current MISR land algorithm combines the benefits of two powerful approaches: (1) the heterogeneous surface algorithm (HET) that makes use of surface contrasts and empirical orthogonal functions to represent the surface hemispherical-directional reflectance factors (HDRFs), and (2) the homogenous surface algorithm (HOMOG) that applies spectral and angular invariance constraints to the surface HDRFs. HOMOG was introduced in 2005 to limit occasional outliers and unphysical region-to-region noise in basic HET AOD retrievals. Recently, extensive testing has shown that HOMOG works very well in the low- to medium-AOD range (0.8), but its application under higher aerosol loadings is problematic due to reduced sensitivity to surface reflection. As a result, retrieved MISR AODs over land tend to become more and more underestimated as pollution levels increase. Here we report on a prototype MISR aerosol retrieval algorithm over land that alleviates this AOD underestimation at medium to high aerosol loadings. The improvements introduced to the basic HET algorithm do not require use of the HOMOG constraint at high AODs, thus removing the main cause for AOD underestimation. Simultaneously, the prototype algorithm shows very high AOD retrieval accuracy (quantitatively) as well as spatial consistency (qualitatively). The results are a testament to the physical principles and empirical prowess of the original multi-angle aerosol retrieval algorithm over heterogeneous surfaces.
Estimating the Subsolar Magnetopause Position from Soft X-ray Images using Lowpass Image Filter
Authors: Kim Hyangpyo , Connor Hyunju , Jung Jaewoong , Walsh Brian , Sibeck David
Published: February 2023

The Lunar Environment Heliospheric X-ray Imager (LEXI, lunar flatform) and Solar wind-Magnetosphere-Ionosphere Link Explorer (SMILE, high apogee Earth-orbiter) will take photos of the Earth’s dayside magnetopause and cusps in soft X-rays after their respective launch in 2024 and 2025 for understanding global magnetic reconnection modes under varying solar wind conditions. To support successful science closure, it is critical to develop techniques to extract magnetopause position from observed soft X-ray images. In this presentation, we introduce a new method that derives subsolar magnetopause position (SMP) as a function of a satellite location and a look direction that gives peak soft X-ray emission. Two assumptions are used in this method: 1. The look direction of maximum soft X-ray emission is the tangent to magnetopause, 2. the magnetopause near a subsolar point is nearly spherical and thus the SMP is equal to the radius of magnetopause curvature. We test this magnetopause tracing method by using the anticipated LEXI soft X-ray images under various solar wind conditions. First, we simulate synthetic soft X-ray images observed from various LEXI locations using the OpenGGCM global magnetosphere MHD model. Galactic background, particle background, and Poisson noises are considered in these images. Then, we apply a lowpass filter to the synthetic LEXI images for removing noises and obtaining accurate look angles of soft X-ray peaks. From filtered images, we calculate SMPs for various LEXI locations and solar wind fluxes, and estimate its accuracy by using the SMPs of OpenGGCM as ground truth. Our method estimates SMPs with an accuracy of <0.3RE and this accuracy improves as the solar wind density increases.
Plasma properties in Ganymede’s wake as observed by Juno/JADE
Authors: Pontoni Angèle , Allegrini Frédéric , Bagenal Fran , Bolton Scott , Connerney John , Ebert Robert , Szalay Jamey , Valek Phil , Wilson Rob
Published: February 2023

We present plasma observations from a previously unexplored wake region of Ganymede’s magnetosphere obtained by the Jovian Auroral Distributions Experiment (JADE) onboard the Juno spacecraft as it flew by Ganymede on June 7th, 2021. This region is highlighted by 1) plasma deflection well downstream of Ganymede's magnetopause, consistent with magnetic field perturbations, 2) plasma composition that is a mix of that in Jupiter’s adjacent plasma sheet or in Ganymede's magnetosphere, and 3) proton, heavy ion and electron distributions that are compressed compared to both adjacent regions. We derive ion and electron velocity distributions, pitch angles, temperatures, and densities inthis newly explored region of Ganymede’s magnetosphere. 
Diurnal and Seasonal Mapping of Martian Ices with EMM/EMIRS
Authors: Stcherbinine Aurélien , Edwards Christopher , Wolff Michael , Altunaiji Eman , Haberle Christopher , Smith Michael , Christensen Philip
Published: February 2023

Condensation and sublimation of ices at the surface of the planet is a key part of both the Martian H2O and CO2 cycles, either from a seasonal or diurnal aspect. If most of the ices are located within the polar caps, surface frost is known to be formed during nighttime down to equatorial latitudes. The Emirate Mars InfraRed Spectrometer (EMIRS) instrument onboard the Emirates Mars Mission (EMM) "Hope" probe is a Fourier Transform Infrared spectrometer that is observing the Martian surface and atmosphere between 6 and 100 μm from February 2022. The unique orbit of EMM allows EMIRS to observe the entire Martian disk at each observation, covering all the surface of the planet across all local times in ~ 4 orbits, which corresponds to ~ 5° of Ls.Here we use the surface temperature data retrieved from the EMIRS spectra (Smith et al. 2022) to detect and map the ice at the surface of the Red Planet. We compute the amplitude of the diurnal temperature variations to derive maps of the presence of ices (either H2O or CO2) at the surface of the planet over the day, which allows us to monitor the seasonal evolution of the polar caps. And, based on the methodology used in Piqueux et al. (2016), we also compute for each EMIRS pixel the corresponding freezing temperature of CO2, according to Clapeyron’s law, and we consider that CO2 ice is present at the surface if the retrieved temperature is below TCO2, ice. This allows us to monitor the timing of the formation and disappearance of the surface CO2 frost under midlatitudes over the Martian night, and its seasonal evolution.
Flow Crossover during Collisionless Magnetic Reconnection: A Particle-Labelling Particle-in-Cell Study
Authors: Malakit Kittipat , Pianpanit Theerasarn , Prapan Pakkapawn , Ruffolo David , Pongkitiwanichakul Peera , Shay Michael , Cassak Paul , Suetrong Piyawat
Published: February 2023

During 2D magnetic reconnection, plasma is normally understood to flow from one of the inflow sides into the diffusion region and then turn sharply and join the outflow on the same side. Using particle-in-cell simulations with a modification to allow us to label ions and electrons by their initial locations, we find that inflowing plasma does not join the outflow on the same side; instead, plasma crosses to the other inflow side before changing direction to produce an outflow jet. Furthermore, we find that ions and electrons undergo different crossover mechanisms leading to different crossing patterns. The ion crossover occurs more locally within the ion diffusion region whereas the electron crossover occurs over a wider region as its mechanism does not require electrons to pass through the electron diffusion region. This flow crossover occurs both in symmetric reconnection and in a more complex scenario such as a guide-feld asymmetric reconnection, suggesting that it is a general feature of collisionless magnetic reconnection. Recognizing the existence of the flow crossover can be important in improving our understanding of reconnection in many situations. This research has been partially supported by Thailand's National Science and Technology Development Agency (NSTDA): High-Potential Research Team Grant Program (N42A650868), grant MRG6180176 from Thailand Science Research and Innovation, and by a grant from Kasetsart University Research and Development Institute.
A new 3D P-wave velocity model for the greater Alpine Region from 24 years of local earthquakes data.
Authors: Bagagli Matteo , Kissling Edi , Diehl Tobias , Molinari Irene
Published: February 2023

The European Alps and its surrounding mountain belts (e.g., the northern Apennines, the northwestern Dinarides, and the western Carpathians) forms a tectonically complex system, referred as the “greater Alpine region” (GAR). Although being extensively  investigated, the evolving dynamic tectonic system and microplates relation are still under debate.From 2016-2019 the AlpArray project, with its seismic network of ~700 broadband sensors, created an unprecedented chance to uniformly investigate the recorded seismicity in the GAR. After the successful compilation of the AlpArray research seismicity catalog (AARSC, Bagagli et al., 2022) we took a major leap to repick the seismicity reported by the European-Mediterranean Seismological Centre (EMSC) from May 2007 to December 2015. We use the same approach as for the AARSC to repick and consistently relocate 1397 events. Eventually, we consistently and homogeneously re-calculated the local magnitudes on the vertical component only (MLv). This allows a better data selection for the inversion stages, avoiding the magnitude scales mixing reported in bulletins. In addition to these two dataset, we also use the already published dataset for the latest GAR tomography spanning the time-period from January 1996 to May 2007 (Diehl et al., 2009). These three combined dataset have an average picking error observations of 0.2 seconds and provide an unique opportunity to perform a local earthquake tomography (LET) in the GAR.We select 2343 MLv >=2.5 well-locatable events (azimuthal gap <180 degree, number of P-observations > 7) for the calculation of a new Minimum 1D model for the GAR. For the inversion procedure, we select 2285 events for a total of 84664 rays. The 99% of the rays are shorter than 350 km. We use SIMULPS software to derive the 3D P-wave velocity model using a model parametrization of 20x20x10 km cells in the well-resolved area. The preliminary velocity model correctly delineates the GAR major tectonic features, and due to the dense ray coverage it provides excellent resolution of the shallow crustal heterogeneities. This model will help the seismological community push forward the understanding of the GAR geodynamics.
Flow, turbulence and morphodynamics of wood structures in rivers: challenges due to shape, porosity, position
Authors: Schnauder Ingo , Blanckaert Koen
Published: February 2023

Wood structures used in river restoration, such as installed log-jams, root boles or entire trees, are challenging for hydraulic engineers. Their impact on flow, turbulence and morphology is difficult to predict quantitatively and even qualitatively for some configurations. Wood structures inherit distinct shape, porosity, position and orientation relative to the flow and analogies to ‘standard’ bluff bodies from literature are not easily transferable. A generalising hydraulic classification scheme and studies towards a standardisation of flow and turbulence properties are thus still lacking. Even more so, if morphodynamics and the associated flow adaptations are of concern.As a starting point, flow and morphologic changes due to installed tree structures were investigated at the TU Wien hydraulics lab for clear-water conditions in a 2.5 m wide flume. Flow depth was H = 0.25 m at a Froude number of Fr = 0.25 and a flow-Reynolds number of Re = 7.7 x 104. The structures were composed of a circular root-plate (D = 0.4 m diameter) with a cylindrical stem attached (0.12 m diameter, 3.0 m long). Root porosity was realised by cutting out sectors of the root-plate and additionally by attaching a porous filter mat. The orientation of the tree was kept streamlined with the flow and two vertical positions of the structure were tested, with the stem afloat near the surface (positively buoyant) and with the stem deposited on the bed (negatively buoyant).The floating installation induced fast-response tunnel-scour underneath and slow-response shear layer scour at both sides downstream of the root-plate. The drowned installation induced initial horseshoe vortex scour until the lower edge of the root-plate was reached and tunnel-scour reshaped the scour hole at its final stage. The vertical and lateral extent of the scour hole controlled flow divergence underneath the root and into the near-wake, causing pronounced upwelling downstream. Upwelling fluid further diverted the shear layers laterally outward and increased the wake width. With increasing root-plate porosity, scour depth, upwelling strength and lateral shear-layer divergence decreased. Root-plate porosity reduces the global velocity gradient between wake and ambient flow as well as the strength of downward directed flow into and upward directed flow out of the scour hole into the wake.
User-friendly climate data discovery and analysis with ESMValCore
Authors: Andela Bouwe , Kalverla Peter , Kazeroni Remi , Loosveldt Tomas Saskia , Predoi Valeriu , Schlund Manuel , Smeets Stef , Zimmermann Klaus
Published: February 2023

The Earth System Grid Federation (ESGF) offers a wealth of climate data that can be used to do interesting research. For example, the latest edition of the Coupled Model Intercomparison Project (CMIP6) output features 20 petabytes of data. However, the heterogeneity of the data can make it difficult to find and work with. Here, we present new features of ESMValCore, a Python package designed to work with large climate datasets available from ESGF and beyond. ESMValCore now provides a Python interface that makes it easy to discover what data is available on ESGF and locally, download it if necessary, and make it analysis-ready. The analysis-ready data can then be used as input to the ESMValCore preprocessor functions, a collection of functions that can be used to perform commonly used analysis steps such as regridding and statistics. When searching for data on ESGF as well as when loading the NetCDF files, the software intelligently corrects small issues in the metadata that otherwise make working with this data a time-consuming, manual effort. Data and metadata issues are fixed in memory for fast performance. The search and download features are user-friendly and will automatically use a different server if one of the ESGF servers is unavailable for some reason. Several Jupyter notebooks demonstrating these new features are available at https://github.com/ESMValGroup/ESMValCore/tree/main/notebooks. ESMValCore has been designed for use on computing systems that are typically used by researchers: it works well on a laptop or desktop computer, but also comes with example configuration files for use on large compute clusters attached to ESGF nodes. For reliable computations, ESMValCore makes use of the Iris library developed by the UK Met Office. This in turn is built on top of Dask, a library for efficient parallel computations with a low memory footprint. In 2023, we aim to improve our use of Dask in collaboration with the Iris developers, for even better computational performance. For easy reproducibility, ESMValCore also offers “recipes” in which standard analyses can be saved. A large collection of such recipes is available in the Earth System Model Evaluation Tool (ESMValTool). ESMValTool started out as a set of community-developed diagnostics and performance metrics for the evaluation of Earth system models. Recently it has also turned out to be useful for other users of climate data, such as hydrologists and climate change impact researchers. Both ESMValCore and ESMValTool are developed by and for researchers working with climate data, with the support of several research software engineers. An important recent achievement is the use of these packages to produce the figures for several chapters of the IPCC AR6 report. Documentation for both ESMValCore and ESMValTool is available at https://docs.esmvaltool.org. 
Airborne Closure of Moisture Budget inside Arctic Atmospheric Rivers
Authors: Dorff Henning , Konow Heike , Schemann Vera , Ori Davide , Mech Mario , Ament Felix
Published: February 2023

Among arctic moist air intrusions, atmospheric rivers (ARs) provide substantial moisture transport over long distances poleward. Along their corridors, warm and moist air masses undergo various transformation processes and can cause regional sea ice decline, especially when they induce precipitation as rain. Quantifying the components of the atmospheric moisture budget in arctic ARs is key to elucidate their precipitation efficiency. We close the AR moisture budget by measurements of the High Altitude LOng range research aircraft (HALO) during the recent HALO-(AC)³ campaign (Spring, 2022) in the vicinity of the Fram Start and Arctic ocean.Our analysis is based on a strong AR event that HALO observed on two consecutive days during the occurrence of a sequence of moist air intrusions mid of March 2022. Dropsondes detect the vertical atmospheric profile and therefrom quantify the integrated water vapour transport (IVT) along AR cross sections. Applying regression methods then allows calculating the divergence of IVT. Since the limited number of dropsondes may deteriorate such calculations, we estimate the arising uncertainties using the ICOsahedral Nonhydrostatic model (ICON) in a storm-resolving configuration. Retrieved moisture profiles from the microwave radiometer (HAMP) further complement the sporadic sonde-based moisture profiles. We use the nadir cloud and precipitation radar mounted aboard HALO to derive precipitation rates along the flight curtains.As the comparison with ICON suggests, the set of dropsondes to derive the IVT divergence within a reasonable range. The advection of moisture is roughly twice as strong as mass convergence. Both components act on different heights, with convergence dominating in the boundary layer (0-1 km) near the low-level jet, whereas moisture advection is more elevated (1-4 km). The strongest moisture convergence arises in the warm prefrontal AR sector while precipitation dominates slightly westwards in the AR centre. The investigated AR event caused rain over sea-ice with a melting layer up to 1.5 km. While there was less IVT on the second observation day, mean precipitation increased from the first day. Model simulations show that evaporation makes only a small contribution to the budget.  Within the ICON simulations, the comparison of precipitation purely based on the along-track radar curtain against that over the entire AR corridor indicates that the along-track curtain captures the mean precipitation intensity of the AR corridor, but misrepresents its spatial variability. However, the HALO devices outperform the ICON simulations in terms of the vertical variability of moisture conversion processes.