bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of electrochemical characteristics of intergel systems based on polyacrylic acid
Authors:   A.B. Bekturov Institute of Chemical Sciences JSC, Jumadilov T.K. ,   Abai Kazakh National Pedagogical University, Suleimenova M.T. ,   A.B. Bekturov Institute of Chemical Sciences JSC; Abai Kazakh National Pedagogical University, Khimersen Kh. ,   A.B. Bekturov Institute of Chemical Sciences JSC, Totkhuskyzy B. ,   A.B. Bekturov Institute of Chemical Sciences JSC, Dyussembaeva G.T. ,   A.B. Bekturov Institute of Chemical Sciences JSC; Abai Kazakh National Pedagogical University, Gražulevicius J.V. ,   Kaunas University of Technology
Published: April 2024

Currently, hydrogels are polymer materials in high demand due to their physicochemical properties, and recent years have seen significant attention given to the study of their physicochemical properties [1,2]. The purpose of this research is to investigate the effect of remote interaction on the electrochemical properties of intergel systems containing hydrogels of polyacrylic acid, poly-4-vinylpyridine, poly-2-methyl-5-vinylpyridine, and polyethyleneimine hydrogels with various initial states. The dependency of conductivity and pH levels in aqueous solutions of intergel systems was examined. The obtained results have shown thatin the 5:1 ratio of the PAAswollen:P4VPdry intergel system, the conductivity of the aqueous medium reaches its maximum value after 24 hours, with a corresponding decrease in pH level. For the PAAdry:P2M5VPdry hydrogels at ratios of 5:1, 1:5, and 2:4, the high electroconductivity was observed at the sixth hour. The maximum pH value was achieved at a ratio of 4:2, indicating a low presence of nitrogen heteroatoms in the aqueous solution. The maximum conductivity in the PAAswollen:PEIswollen system at a 3:3 ratio was reached after 8.5 hours, while the pH showed its minimum value. In the study of the PAAdry:PEIdry intergel system, the pH of the aqueous medium decreased over time in all hydrogel ratios. An exception was noted at a 4:2 ratio, where pH slightly increased after 0.5 hours, then fell again, showing a deviation from the general pH trend. Conclusion. The conducted research has shown that specific conductivity varies across all molar ratios of hydrogels. It was established that changes in pairs and states of hydrogels in the intergel system affect specific conductivity, indicating the ratio of ionized and dissociated groups in the chain changes normally. These results demonstrate that these intergel systems can be used to get high-selectivity sorbents.
Influence of layered conductive coatings on electrochemical characteristics of NaFe(SO4)2cathode material
Authors:   Al-Farabi Kazakh National University, Ryabicheva M.A. , Zhigalyonok Ya.S. ,   Al-Farabi Kazakh National University, Malchik F.I. ,   Al-Farabi Kazakh National University
Published: April 2024

Rising production and consumption, and the high cost of lithium salts increased the price of lithium-ion batteries. Sodium-ion batteries are a promising replacement as safer and cheaper. However, the cathode materials for these batteries have low conductivity, which critically reduces their capacity. Modification with conductive additives is one way to solve this problem. Since a large electronic contact area of the active material with the conductive coating is required, the main candidates for such additives are materials with a layered structure. The purpose. To study the influence of layered conductive additives on the performance and kinetic parameters of eldfellite-structured cathode material. Methodology. By cyclic voltammetry and galvanostatic methods, it is found that as the 2D material additive concentration increases, the active material’s performance characteristics initially increase and then decrease, which is related to the sodium ions diffusion rate through the coating layer. Results and discussion. As a result of the modification effect evaluation of NaFe(SO4)2 cathode material with eldfellite structure by layered conductive coatings: graphite, molybdenum disulfide and MXene (Ti3C2Tx), it was determined that for each material there is a certain optimal concentration at which peak currents, capacitance and diffusion coefficient are maximized and resistance is minimized. The optimum additive quantities are 0.5% for MoS2 and MXene, and 0.2% for graphite. Conclusion. The influence of the concentration of 2D conductive coatings on the electrochemical properties of NaFe(SO4)2 intercalation material is shown.
Influence of ionic radius on the degree of extraction of rare earth metals during sorption by the interpolymer system AMBERLITE IR-120 –AВ-17-8
Authors:   A.B. Bekturov Institute of Chemical Sciences JSC, Jumadilov T.К. , Khimersen Kh. ,   A.B. Bekturov Institute of Chemical Sciences JSC, Imangazy A.M. ,   A.B. Bekturov Institute of Chemical Sciences JSC, Haponiuk J. ,   Gdansk University of Technology
Published: April 2024

Studies have been carried out on the sorption of rare earth metal ions in solution using the interpolymer system Amberlite IR-120:AB-17-8. The purpose of the work is to search for conditions for maximum sorption of rare earth elements (Dy, Tb, Gd, Eu and Sm) from aqueous solutions using the effect of remote interaction of ion exchange resins. Methodology. The residual concentrations of rare earth ions were determined using an Optima 8300DV Duo inductively coupled plasma spectrometer. Results. The best sorption characteristics were determined by the interpolymer system at a ratio of 3:3. The residual concentration of rare earth elements in the solution was: Dy – 4.64 mg/l, Tb – 4.16 mg/l, Gd – 4.21 mg/l, Eu – 4.16 mg/l, Sm – 4.56 mg/l. The variations in the ionic radius of the ions chosen for the study are Dy3+<Tb3+<Gd3+<Eu3+<Sm3+. The degree of sorption of interpolymer system increased with increasing ionic radius of the metals. For dysprosium with the smallest ionic radius, the degree of sorption was η – 52%, and for terbium, gadolinium and europium it increased to η – 58%. For individual Amberlite IR-120 (6:0), the degree of sorption of terbium ions was 47%. Conclusion. The results of the study showed that the interpolymer system with a ratio of 3:3 has the best sorption activity. It has been established that the degree of sorption of interpolymer pairs increases with increasing order of the ionic radius of metals (Tb3+< Gd3+< Eu3+).
Synthesis and characterization of n-isopropylacrylamide based copolymers with silver nanoparticles
Authors:   Satbayev University, Nakan U. , Yermaganbetov M.E. ,   Satbayev University, Nursultanov М.Е. ,   Satbayev University, Kerimkulova A.Zh. ,   Satbayev University, Zhursumbayeva M.B. ,   Satbayev University, Kydyrkhan A. ,   Al-Farabi Kazakh National University
Published: April 2024

In recent years, the so-called "smart" polymers, which can systematically respond to small environmental changes, such as pH, temperature and electric field, are widely used in many fields. Researchers are particularly interested in using drugs to transport to the right place in the human body. One of the types of these smart polymers are thermosensitive polymers. Among the thermosensitive polymers, the most well-known are homo- and copolymers based on N-isopropylacrylamide. In the research work, in order to improve the properties of thermosensitive polymers, silver nanoparticles were added to the hydrogel composition. Hydrogels based on N-isopropylacrylamide and 2-hydroxyethylacrylate monomers were synthesized by radical polymerization in solution (in H2O and AgNO3 solution). While the production of silver nanoparticles is based on the redox (by NaBH4 solution) mechanism, the formation of these nanoparticles in the gel was carried out by diffusion. While the introduction of silver nanoparticles into the gel was controlled by ultraviolet spectroscopy, its inclusion in the gel was confirmed using a scanning electron microscope (SEM). Meanwhile, a hydrogel containing silver nanoparticles exhibits antibacterial properties, it was investigated using biomedical tests. It has been shown here that a hydrogel containing silver has good antibacterial properties, whereas a hydrogel without silver does not have the ability to destroy bacteria.
Synthesis and physico –chemical characteristics of complex ferriteCrNaFe2O5
Authors:   Kazakh State Women`s Teacher Training University, Mataev M.М. , Madiyarova A.M. ,   Kazakh State Women`s Teacher Training University, Patrin G.S. ,   Siberian Federal University, Abduraimova М.R. ,   Kazakh State Women`s Teacher Training University, Nurbekova M.A. ,   Kazakh State Women`s Teacher Training University, Tursunova Zh.I. ,   Kazakh State Women`s Teacher Training University
Published: April 2024

The article discusses for the first time the synthesis, radiographic and electron microscopic examination of CrNaFe2O5, synthesized using the high – temperature Sol-gel method. The phase of complex ferrites was synthesized using Sol-Gel synthesis method at high temperature. Initially, the structure of CrNaFe2O5 composite ferrite was researched by X-ray phase analysis and SEM, the syngony type, elementary cell parameters, radiographic and pycnometric densities and elemental analysis were defined: CrNaFe2O5 -а=5.0289, в= 5.0289, с=13.6938 Å , ρx-ray.= 5.327 g/sm3 , ρpycn.=5.331 g/sm3. A comparative analysis of the connection between the parameters of the Crystal cell of the initial materials and of the obtained complex ferrites was carried out. Through a scanning electron microscope, microsystems were taken from different parts of CrNaFe2O5 type crystallite, the elemental composition of crystals was analyzed, and the general type of surface layer of complex ferrite was displayed. As a result, the fact that the compound consists of a single phase, the clarity of its construction was determined by the topography and chemical composition of the compound. Consequently, it was discovered that the newly synthesized complex ferrites correspond to the formula CrNaFe2O5. The particles of the formed compounds have a large size (between 200 µm, 20.0 µm and 5 µm). The results of the element analysis show that the compound is compatible.
An electrochemical method for the regeneration of trivalent iron to increase the efficiency of in-situ leaching of uranium
Authors:   National Center on Complex Processing of Mineral Raw Materials of the Republic of Kazakhstan, Bayeshov А. , Bayeshova А. ,   Al-Farabi Kazakh National University, Turlybekova М. ,   Abai Kazakh National Pedagogical University, Myrzabekov B. ,   D.V. Sokolskiy Institute of Fuel, Catalysis and Electrochemistry
Published: April 2024

Due to the increasing demand for electricity with the development of production and general infrastructure, increasing the production of uranium as an economically and environmentally efficient source of energy is an urgent problem. The purpose of this study is to develop an electrochemical method for the regeneration of iron (III) ions used as a uranium oxidizer in the process of in-situ leaching of uranium minerals with sulfuric acid solutions. Methods. The mechanism of reactions in the iron (II)-iron (III) redox system was studied by recording potentiodynamic polarization curves and conducting electrolysis of the oxidation of divalent iron ions under galvanostatic conditions. Results and discussion. Cathode-anodic and anodic-cathode cyclic polarization curves taken on platinum electrodes showed that the redox reactions of iron ions are reversible and these reactions occur at a slight overvoltage. The influence of the main electrochemical parameters (current density, concentrations of iron (II) ions and sulfuric acid) on the oxidation of divalent iron ions was studied for the first time using granular anode electrodes, the electrode spaces of which are separated by an anionite membrane. It has been found that the use of granular graphite electrodes in the oxidation divalent iron ions increases the current output by more than 2 times compared to a plate graphite electrode. Conclusion. According to the results of the study, it was noted that under optimal conditions, the current output of the oxidation of divalent iron ions exceeds 90%. Extensive research has shown that trivalent iron ions, widely used in the in-situ leaching process for uranium production, can be regenerated by electrochemical methods.
Synthesis of quaternary ammonium saltsisonicotinic and nicotinic hydrazones acids and their anti-inflammatory activity
Authors:   Institute of Organic Synthesis and Coal Chemistry of the Republic of Kazakhstan, Nurkenov O.A. , Mendibayeva A.Zh. ,   Institute of Organic Synthesis and Coal Chemistry of the Republic of Kazakhstan, Fazylov S.D. ,   Institute of Organic Synthesis and Coal Chemistry of the Republic of Kazakhstan, Seilkhanov T. M. ,   Sh. Ualikhanov Kokshetau University, Kabieva S.K. ,   Karaganda Industrial University, Satbayeva E.M. ,   S.D. Asfendiyarov Kazakh National Medical University, Karipova G.Zh. ,   Institute of Organic Synthesis and Coal Chemistry of the Republic of Kazakhstan, Syzdykov A.K. ,   Karaganda Industrial University
Published: April 2024

Currently, the number of infections caused by strains of bacteria that are not sensitive to antibiotics and antiseptics is growing worldwide. A similar increase in bacterial resistance is observed for both nosocomial infections and community-acquired human-to-human infections. An important task for chemists and pharmacologists is the synthesis of new compounds and the establishment of a structure-bioactivity relationship. The purpose of this work is to study the effect of the structure of quaternary ammonium derivatives of hydrazones of isonicotinic and nicotinic acids on the manifestation of their anti-inflammatory properties. Results and discussion. The alkylation of nicotinic acid hydrazones produced their new quaternary ammonium salts (43.7-70.7%). The methodology for the synthesis of quaternary ammonium compounds of hydrazones included obtaining a variety of structures by introducing one or two fluorine and bromine-containing fragments into their structure. The structure of compounds was confirmed by 1H, 13C NMR spectroscopy. Conclusion. New quaternary ammonium salts of nicotinic acid hydrazones have been obtained. The study of anti-inflammatory activity was carried out using the method of formalin paw edema in rats. The acute inflammatory reaction was reproduced by subplantar administration of 2% formalin solution. Compared with ibuprofen at a dosage of 100 mg/kg, these compounds were ineffective (p2<0.05). According to the results of the analysis of possible pharmacological effects, it was also revealed that new compounds may have an effect on the regulation and production of ketone bodies, the enzymatic activity of transaminases. New alkylated hydrazones of isonicotinic and nicotinic acids may be of interest for studying their antituberculous and antiviral activities.
Los trastornos de la personalidad ¿realidad o ficción? El sombrío futuro de su diagnóstico
Authors: Caballo Vicente , López Andrea , Salazar Isabel
Published: April 2024

El diagnóstico categorial de los trastornos de la personalidad (TTPP) ha sido criticado por diversas razones, entras las que se encuentran el solapamiento de síntomas entre distintos trastornos, su elevada comorbilidad o el carácter dicotómico de su diagnóstico. Estas críticas han llevado al desarrollo de un planteamiento dimensional en las últimas versiones de los sistemas de clasificación, DSM-5/DSM-5-TR y CIE-11, considerando dos aspectos: el funcionamiento de la personalidad y una serie de rasgos patológicos. A pesar de la cuantiosa literatura publicada desde principio de este siglo sobre esta propuesta dimensional, no está claro, a día de hoy, que tenga alguna utilidad clínica. La vaga, abstracta y poco operativizable exposición de lo que constituye el funcionamiento de la personalidad y la compleja y forzada designación de rasgos mayores y menores (facetas) en el DSM-5/DSM-5-TR o sólo mayores y opcionales en la CIE-11, complican el diagnóstico dimensional de los TTPP. En este trabajo se discuten todas estas cuestiones en un intento de aportar algo de luz para un futuro menos sombrío que el actual panorama de los TTPP.
Datos normativos, fiabilidad y validez de las escalas de trastornos de la personalidad del NEO PI-R
Authors: Sanz-García Ana , García-Vera María Paz , Sanz Jesús
Published: April 2024

Hay un creciente interés por entender los trastornos de la personalidad (TTPP) desde el modelo de los cinco factores. Miller et al. (2005) y Costa y McCrae (2005) propusieron dos conjuntos de escalas basadas en las facetas del “Inventario de personalidad NEO-revisado” (NEO PI-R) para evaluar los TTPP del DSM-5. Existen baremos españoles para las escalas de Miller et al. (2005) a partir de muestras de selección de personal, pero no son apropiados en contextos con deseabilidad social baja. Se presentan datos normativos, de fiabilidad y validez convergente/ discriminante para ambos conjuntos de escalas con voluntarios de la población general española (N= 682). Los índices de consistencia interna y validez convergente/ discriminante fueron excelentes o buenos para todas las escalas, especialmente para las de Miller et al. (2005). Las diferencias entre la muestra de voluntarios y de selección de personal (d= 0,61) y entre varones y mujeres (d= 0,34-0,38) justifican el desarrollo de baremos para los dos conjuntos de escalas de TTPP para situaciones de deseabilidad social baja y separados por sexo. Se discute su utilidad en diferentes contextos.
Understanding difficult temperament in adults: A mixed-methods study
Authors: Lazdauskas Tomas
Published: April 2024

Difficult temperament is a set of behavioral characteristics that are associated with mental health and a significant predictor of psychopathology. This study aims to investigate which temperamental characteristics can be considered attributes of difficult temperament in Lithuanian adults. The sample consisted of 429 adults between 18 and 79 years of age. The Adult Temperament Questionnaire was used to assess temperamental characteristics and perceived difficult temperament. Data were analyzed using a mixed-methods approach. The results revealed that the set of attributes perceived as constituting difficult temperament includes characteristics such as negative mood, intensity of emotional reactions, low adaptability, withdrawal, and low regularity. Quantitative data analysis uncovered an unexpected negative relationship between perceived difficult temperament and the rhythmicity characteristic, while a new category of stubbornness emerged in the qualitative data. The findings provide new knowledge about both the cultural specifics of difficult temperament and the content of the temperament construct in general. These results can also aid in the development of further research on difficult temperament, as well as in the planning of mental health interventions and psychological counseling.
PROCESSO TRANSEXUALIZADOR E DIREITO À SAÚDE: DESAFIOS PARA A PRÁTICA MÉDICA NO CENÁRIO DO SUS
Authors: Valois Rogério Magalhães , Shibata Larissa Yoshie , Coelho Erik William Farias , Tavares Álvaro Alberto de Oliveira , Santos Matheus Prado dos , Soeiro Ana Cristina Vidigal
Published: April 2024

Introdução: Apesar dos avanços alcançados no contexto da atenção em saúde, as pessoas trans ainda são vítimas de muito preconceito e discriminação. Nesse sentido, o processo transexualizador representa um dos avanços no âmbito das políticas em saúde, especialmente no contexto do Sistema Único de Saúde (SUS). Trata-se de uma área de cuidado interdisciplinar, a qual demanda uma atenção integral, acolhedora e respeitosa, em que as intervenções médicas têm muito a contribuir. Objetivos: Identificar os desafios relacionados ao processo transexualizador no cenário do SUS e discutir as implicações para a prática médica. Metodologia: Revisão Integrativa de Literatura (RIL) de caráter descritiva e transversal, realizada mediante pesquisa documental, com acesso a bases de dados e registros do Sistema de Informações Hospitalares. Resultados/Discussão: No total, 13 estudos compuseram a revisão, tendo sido elencados três eixos de discussão: cuidados perioperatórios relacionados ao processo transexualizador; processo transexualizador no contexto do SUS; qualidade de vida das pessoas trans pós processo transexualizador. Conclusão: A compreensão das necessidades e desafios enfrentados pela comunidade trans é essencial para orientar práticas médicas eficazes e que respeitem os direitos das pessoas trans no cenário do SUS.
A filosofia de Thomas Kuhn e suas implicações para o ensino de Física
Authors: Lima de Souza Junior Francisco de Assis , Sousa Celia R. , Monteiro Fróes Maira , Tamiasso Martinhon Priscila , Silva Maria de Lourdes da , Simões Grazieli
Published: April 2024

Neste artigo buscamos mostrar que a História da Ciência pode tornar-se um importante recurso pedagógico para o ensino de Física frente às mudanças curriculares e estruturais que o sistema educacional brasileiro está sofrendo. Em especial, pretendemos mostrar também que as ideias do filósofo da ciência Thomas Kuhn podem ser aplicadas ao ensino de Física contribuindo para a aprendizagem dos alunos e modificando a visão do professor sobre as suas metodologias. Realizamos então uma busca de trabalhos e teses que apresentavam propostas de ensino de Física cuja filosofia kuhniana servia de base. Destacamos alguns desses trabalhos, dos quais analisamos a clareza da proposta didática, a viabilidade de aplicação e os possíveis benefícios pedagógicos.  Esperamos com este trabalho contribuir para a área de Ensino de Física e incentivar mais estudos sobre a epistemologia de Kuhn aplicada à educação.
Weakened aerosol–radiation interaction exacerbating ozone pollution in eastern China since China's clean air actions
Authors: Yang Hao , Chen Lei , Liao Hong , Zhu Jia , Wang Wenjie , Li Xin
Published: April 2024

Abstract. Since China's clean air action, PM2.5 (particulate matter with an aerodynamic equivalent diameter of 2.5 µm or less) air quality has improved, while ozone (O3) pollution has become more severe. Here we apply a coupled meteorology–chemistry model (WRF-Chem: Weather Research and Forecasting model coupled to Chemistry v3.7.1) to quantify the responses of aerosol–radiation interaction (ARI) to anthropogenic emission reductions from 2013 to 2017, including aerosol–photolysis interaction (API) related to photolysis rate change and aerosol–radiation feedback (ARF) related to meteorological field change and their contributions to O3 increases over eastern China in summer and winter. Sensitivity experiments show that the decreased anthropogenic emissions play a more prominent role in the increased daily maximum 8 h average (MDA8) O3 in both summer (+1.96 ppb vs. +0.07 ppb) and winter (+3.56 ppb vs. −1.08 ppb) than the impacts of changed meteorological conditions in urban areas. The decreased PM2.5 caused by emission reductions can result in a weaker impact of ARI on O3 concentrations, which superimposes its effect on the worsened O3 air quality. The weakened ARI due to decreased anthropogenic emissions aggravates the summer (winter) O3 pollution by +0.81 ppb (+0.63 ppb), averaged over eastern China, with weakened API contributing 55.6 % (61.9 %) and ARF contributing 44.4 % (38.1 %), respectively. This superimposed effect is more significant for urban areas during summer (+1.77 ppb). Process analysis indicates that the enhanced chemical production is the dominant process for the increased O3 concentrations caused by weakened ARI in both summer and winter. This study innovatively reveals the adverse effect of weakened aerosol–radiation interaction due to decreased anthropogenic emissions on O3 air quality, indicating that more stringent coordinated air pollution control strategies should be implemented for significant improvements in future air quality.
East Antarctic Ice Sheet Variability In The Central Transantarctic Mountains Since The Mid Miocene
Authors: Bromley Gordon , Balco Greg , Jackson Margaret , Balter-Kennedy Allie , Thomas Holly
Published: April 2024

Abstract. The response of the East Antarctic Ice Sheet to warmer-than-present climate conditions has direct implications for projections of future sea level, ocean circulation, and global radiative forcing. Nonetheless, it remains uncertain whether the ice sheet is likely to undergo net loss due to amplified melting coupled with dynamic instabilities, or whether such losses will be balanced, or even offset, by enhanced accumulation under a higher precipitation regime. The glacial-depositional record from the central Transantarctic Mountains (TAM) provides a robust geologic means to reconstruct the past behaviour of the East Antarctic Ice Sheet, including during periods thought to have been warmer than today, such as the Mid Pliocene Warm Period (~3.3–3.0 Ma). This study describes a new surface-exposure-dated moraine record from Otway Massif in the central TAM spanning the last ~9 Myr, and synthesises these data in the context of previously published moraine chronologies constrained with cosmogenic nuclides. The resulting record, although fragmentary, represents the majority of direct and unambiguous terrestrial evidence for the existence and size of the East Antarctic Ice Sheet during the last 14 Myr, and thus provides new insight into the long-term relationship between the ice sheet and global climate. At face value, the existing TAM moraine record does not exhibit a clear signature of the Mid Pliocene Warm Period, thus precluding a definitive verdict on the East Antarctic Ice Sheet’s response to this event. In contrast, an apparent hiatus in moraine deposition both at Otway Massif and neighbouring Roberts Massif suggests that the ice sheet surface in the central TAM potentially was lower than present during the Late Miocene and earliest Pliocene.
Meteorological ingredients of heavy precipitation and subsequent lake filling episodes in the northwestern Sahara
Authors: Rieder Joëlle C. , Aemisegger Franziska , Dente Elad , Armon Moshe
Published: April 2024

Abstract. The dry Sahara was potentially wetter in the past during the warm African Humid Period. Although debated, this climatic shift is a possible scenario in a future warmer climate. One major line of evidence reported for past green periods in the Sahara is the presence of paleo-lakes. Even today, Saharan desert lakes get filled from time to time. However, very little is known about these events due to the lack of available in-situ observations. In addition, the hydrometeorological conditions associated with these events have never been systematically investigated. This study proposes to fill this knowledge gap by examining the meteorology of lake-filling episodes (LFEs) of Sebkha el Melah – a commonly dry lake in the northwestern Sahara. Heavy precipitation events (HPEs) and LFEs are identified using a combination of precipitation observations and lake volume estimates derived from satellite remote sensing. Weather reanalysis data is used together with three-dimensional trajectory calculations to investigate the moisture sources and characteristics of weather systems that lead to HPEs and to assess the conditions necessary for producing LFEs. Results show that hundreds of HPEs occurred between 2000 and 2021, but only 6 LFEs eventuate. The ratio between the increase in lake water volume during LFEs and precipitation volume during the HPEs that triggered the lake-filling, known as the runoff coefficient, provides a very useful characteristic to assess storm impacts on water availability. For the 6 LFEs investigated in this study, the runoff coefficient ranges across five orders of magnitude and is much smaller than the figures often cited in the literature for the Sahara. We find that LFEs are generated most frequently in autumn by the most intense HPEs, for which the key ingredients are (i) the formation of surface extratropical cyclones to the west of the Atlantic Sahara coastline in interplay with upper-level troughs and lows, (ii) moisture convergence from the tropics and the extratropical North Atlantic, (iii) a premoistening of the region upstream of the catchment over the Sahara through a recycling-domino-process, (iv) coupled or sequential lifting processes (e.g., orographic lifting and large-scale forcing), and (v) the stationarity of synoptic systems that result in long-duration (typically 3 d) HPEs. Based on the insights gained into Saharan LFEs in the present-day climate, we suggest that the initial filling and persistence of Saharan lakes may be related to changes in the intensity and frequency of HPEs, rather than a change to mean precipitation alone. Future studies can leverage these insights to better assess the mechanisms involved in the greening of the Sahara in the past and also in a warmer future.
Quantifying uncertainties of satellite NO2 superobservations for data assimilation and model evaluation
Authors: Rijsdijk Pieter , Eskes Henk , Dingemans Arlene , Boersma Folkert , Sekiya Takashi , Miyazaki Kazuyuki , Houweling Sander
Published: April 2024

Abstract. Satellite observations of tropospheric trace gases and aerosols are evolving rapidly. Recently launched instruments provide increasingly higher spatial resolutions with footprint diameters in the range of 2–8 km, with daily global coverage for polar orbiting satellites or hourly observations from geostationary orbit. Often the modelling system has a lower spatial resolution than the satellites used, with a model grid size in the range of 10–100 km. When the resolution mismatch is not properly bridged, the final analysis based on the satellite data may be degraded. Superobservations are averages of individual observations matching the resolution of the model and are functional to reduce the data load on the assimilation system. In this paper, we discuss the construction of superobservations, their kernels and uncertainty estimates. The methodology is applied to nitrogen dioxide tropospheric column measurements of the TROPOMI instrument on the Sentinel-5P satellite. In particular, the construction of realistic uncertainties for the superobservations is non-trivial and crucial to obtaining close to optimal data assimilation results. We present a detailed methodology to account for the representativity error when satellite observations are missing due to e.g. cloudiness. Furthermore, we account for systematic errors in the retrievals leading to error correlations between nearby individual observations contributing to one superobservation. Correlation information is typically missing in the retrieval products where an error estimate is provided for individual observations. The various contributions to the uncertainty are analysed: from the spectral fitting, the estimate of the stratospheric contribution to the column and the air-mass factor. The method is applied to TROPOMI data but can be generalised to other trace gases such as HCHO, CO, SO2 and other instruments such as OMI, GEMS and TEMPO. The superobservations and uncertainties are tested in the ensemble Kalman filter chemical data assimilation system developed by JAMSTEC. These are shown to improve forecasts compared to thinning or compared to assuming fully correlated or uncorrelated uncertainties within the superobservation. The use of realistic superobservations within model comparisons and data assimilation in this way aids the quantification of air pollution distributions, emissions and their impact on climate.
Instantaneous intraday changes in key meteorological parameters as a proxy for the mixing ratio of BVOCs over vegetation under drought conditions
Authors: Li Qian , Gabay Maor , Dayan Chen , Misztal Pawel , Guenther Alex , Fredj Erick , Tas Eran
Published: April 2024

Abstract. Biogenic volatile organic compounds (BVOCs) exert a significant influence on photochemical air pollution and climate change, with their emissions strongly affected by meteorological conditions. However, the effect of drought on BVOC emissions is not well-characterized, limiting the predictive power of this feedback on climate change and air quality. This study hypothesized that under severe drought conditions, BVOC emissions will be more sensitive to instantaneous intraday variations in meteorological parameters than to the absolute values of those parameters. To test this hypothesis, we employed proton transfer reaction time-of-flight mass spectrometry to quantify the mixing ratios of a suite of soluble and insoluble VOCs, including isoprene, monoterpenes, sesquiterpenes, acetone, acetaldehyde, methanol, ethanol, formaldehyde, formic acid, acetic acid, 1,3-butadiene, dimethyl sulfide (DMS), and H2S, under severe drought conditions in a natural Eastern Mediterranean forest in autumn 2016. Except for H2S, which was used as a control, and to a certain extent DMS, all measured VOCs exhibited a strong response to changes in relative humidity, with lower mixing ratios observed around noon, suggesting inhibition of BVOC emission under the relatively high temperature and low relative humidity of drought conditions. Notably, our analysis revealed that instantaneous changes in meteorological conditions, especially in relative humidity, can serve as a better proxy for drought-related changes in BVOC emission rate than the absolute values of meteorological parameters. These findings are supported by direct flux measurements conducted in a mixed Mediterranean forest under drought conditions, in the same region, and presented as a companion article. The findings further highlight the importance of analyzing the effect of meteorological conditions on BVOC emissions under drought conditions on a daily—or shorter—timescale, and support biogenic emission sources for 1,3-butadiene.
The behaviour of charged particles (ions) during new particle formation events in urban Leipzig (Germany)
Authors: Rowell Alex , Brean James , Beddows David C. S. , Shi Zongbo , Kumar Avinash , Rissanen Matti , Dal Maso Miikka , Mettke Peter , Weinhold Kay , Merkel Maik , Harrison Roy M.
Published: April 2024

Abstract. Air ions are electrically charged molecules or particles in air. They are found in the natural environment. Charging accelerates the formation and growth of new aerosol particles. A Neutral cluster and Air Ion Spectrometer was deployed in Leipzig, Germany, to measure the number size distribution of ions from 0.8 to 42 nm, between July 27th and August 25th 2022. Charged particles were mobility classified into small (0.8–1.6 nm), intermediate (1.6–7.5 nm), and large (7.5–22 nm) fractions and their mean concentrations (sum of positive and negative polarities) during the campaign were 462, 88, and 420 cm-3, respectively. The study found that small charged particles were primarily associated with radioactive decay during the early hours, while the intermediate and large charged fractions were linked to photochemistry and local air pollution, as indicated via synchronous peaks in sulphuric acid dimer and black carbon concentrations, respectively. NPF events, observed on 30 % of days, coincided with intense solar radiation. Small charged particle concentrations were lower on NPF event days, whereas the intermediate and large charged species exhibited higher concentrations. The apparent contributions of charged species to 3 and 7.5 nm particles formation rates were 5.7 and 12.7 %, respectively, with mean growth rates of 4.0 and 5.2 nm h-1. Although the ratio of apparent formation rates for charged to uncharged nanoparticles of 3 nm suggested a minor role for charged species in NPF, a substantial increase in intermediate and large charged species was associated with NPF events. The findings contribute valuable insights into the complex interplay between charged species and particle formation in urban environments.
Monitoring snow depth variations in an avalanche release area using low cost LiDAR and optical sensors
Authors: Ruttner-Jansen Pia , Voordendag Annelies , Hartmann Thierry , Glaus Julia , Wieser Andreas , Bühler Yves
Published: April 2024

Abstract. Snow avalanches threaten people and infrastructure in mountainous areas. For the assessment of temporal protection measures of infrastructure in dangerous situations, local and up to date information is crucial. One factor influencing the avalanche situation is wind drifted snow, which causes variations in snow depth across a slope, but this data is rarely available. We present a monitoring system using low cost LiDAR and optical sensors, which we use to monitor snow depth variations in an avalanche release area. The system is operational since November 2023, autonomously measuring and providing data from our study area close to Davos in Switzerland, with high spatiotemporal resolution. In the first three operating months we gained experiences and made a preliminary assessment of the system performance. An analysis of the changes in spatial coverage shows the limitations and potentials of the system under different weather conditions. A comparison of the surface models derived from the LiDAR data and a photogrammetric drone shows a good agreement, achieving a mean of 0.005 m and standard deviation of 0.15 m. Two case studies, including an avalanche event and a period of snowfall with strong winds, show the potential of the proposed system to detect changes in the snow depth distribution on a low decimeter level, or better. In addition, we record meteorological parameters which we will use in future, together with the newly established snow depth database, for attempts to refine and further develop models for wind-induced snow redistribution. The near real time information of the snow depth distribution in avalanche prone slopes will be provided to experts, so it can aid their decisions on avalanche safety measures.
Reconstructing ice phenology of lake with complex surface cover: A case study of Lake Ulansu during 1941–2023
Authors: Huo Puzhen , Lu Peng , Cheng Bin , Yu Miao , Wang Qingkai , Li Xuewei , Li Zhijun
Published: April 2024

Abstract. Lake ice phenology plays a critical role in determining the hydrological and biogeochemical dynamics of the catchment and regional climate. Lakes with complex shorelines and abundant aquatic vegetation are challenging for lake ice phenology retrieval using remote sensing data, primarily due to mixed pixels containing plants, land and ice. To tackle this challenge, a new double-threshold moving t test (DMTT) algorithm, utilizing multisource satellite-derived brightness temperature data at a 3.125-km resolution and long-term weather data, was introduced to capture Lake Ulansu’s ice phenology from 1979 to 2023. Compared to the previous moving t test algorithm, the new DMTT algorithm employs air temperature time series to assist in determining abrupt change points and uses two distinct thresholds to calculate the freeze-up start (FUS) and break-up end (BUE) dates. This method improved the detection of ice information effectively for the mixed pixels. Furthermore, we extended Lake Ulansu's ice phenology detection backward to 1941 using a random forest (RF) model. The reconstructed ice phenology from 1941 to 2023 indicated that Lake Ulansu had average FUS and BUE dates of November 15 ± 5 and March 25 ± 6, respectively, with an average ice cover duration of 130 ± 8 days. Air temperature was the primary impact factor, accounting for 56.5 % and 67.3 % of the variations in the FUS and BUE dates, respectively. We reconstructed, for the first time, the longest ice phenology over a large shallow lake with complex surface cover. We argue DMTT can effectively be applied to retrieve lake ice phenology for this type of lake that have not been fully explored worldwide.
Hydrography and circulation below Fimbulisen Ice Shelf, East Antarctica, from 12 years of moored observations
Authors: Lauber Julius , Hattermann Tore , de Steur Laura , Darelius Elin , Fransson Agneta
Published: April 2024

Abstract. Future mass loss from the East Antarctic Ice Sheet represents a major uncertainty in projections of future sea level rise. Recent studies have highlighted the potential vulnerability of the East Antarctic Ice Sheet to atmospheric and oceanic changes, but long-term observations inside the ice shelf cavities are rare, especially in East Antarctica. Here, we present new insights from observations from three oceanic moorings below Fimbulisen Ice Shelf from 2009 to 2021. We examine the characteristics of Warm Deep Water (WDW) intrusions across a sill connecting the cavity to the open ocean, and investigate seasonal variability of the circulation and water masses inside the cavity. In autumn, solar-heated, buoyant Antarctic Surface Water (ASW) reaches below the 350 m deep central part of the ice shelf, separating colder Ice Shelf Water from the ice base and affecting the cavity circulation on seasonal timescales. At depth, the occurrence of WDW is associated with the advection of cyclonic eddies across the sill into the cavity. These eddies reach up to the ice base. The warm intrusions occur favorably from January to March and from September to November, and traces of WDW-derived meltwater close to the ice base imply an overturning of these warm intrusions inside the cavity. We suggest that both the offshore thermocline depth and interactions of the Antarctic Slope Current with the ice shelf topography over the continental slope cause this timing. Our findings provide a better understanding of the interplay between shallow ASW and deep WDW inflows for basal melting at Fimbulisen, with implications for the potential vulnerability of the ice shelf to climate change.
Equity and justice should underpin the discourse on tipping points
Authors: Pereira Laura M. , Gianelli Ignacio , Achieng Therezah , Amon Diva , Archibald Sally , Arif Suchinta , Castro Azucena , Chimbadzwa Tapiwa Prosper , Coetzer Kaera , Field Tracy-Lynn , Selomane Odirilwe , Sitas Nadia , Stevens Nicola , Villasante Sebastian , Armani Mohammed , Kimuyu Duncan M. , Adewumi Ibukun J. , Lapola David M. , Obura David , Pinho Patricia , Roa-Clavijo Felipe , Rocha Juan , Sumaila U. Rashid
Published: April 2024

Abstract. Radical and quick transformations towards sustainability will be fundamental to achieving a more sustainable future. However, deliberate interventions to reconfigure systems will result in winners and losers, with the potential for greater or lesser equity and justice outcomes. Positive tipping points (PTPs) have been proposed as interventions in complex systems with the aim to (a) reduce the likelihood of negative Earth system tipping points and/or (b) increase the likelihood of achieving just social foundations. However, many narratives around PTPs often do not take into account the entire spectrum of impacts the proposed alternatives could have or still rely on narratives that maintain current unsustainable behaviours and marginalize many people (i.e. do not take “b” into account). One such example is the move from petrol-based to electric vehicles. An energy transition that remains based on natural resource inputs from the Global South must be unpacked with an equity and justice lens to understand the true cost of this transition. There are two arguments why a critical engagement with these and other similar proposals needs to be made. First, the idea of transitioning through a substitution (e.g. of fuel) while maintaining the system structure (e.g. of private vehicles) may not necessarily be conceived as the kind of radical transformation being called for by global scientific bodies like the Intergovernmental Panel on Climate Change (IPCC) and Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). Second, and probably more importantly, the question of positive for whom, positive where, and positive how must be considered. In this paper, we unpack these narratives using a critical decolonial view from the south and outline their implications for the concept of tipping points.
A hydrogeomorphic dataset for characterizing catchment hydrological behavior across the Tibetan Plateau
Authors: Guo Yuhan , Zheng Hongxing , Yang Yuting , Sang Yanfang , Wen Congcong
Published: April 2024

Abstract. Hydrologic and geomorphic processes are intricately linked within the Earth system, jointly characterizing terrestrial hydrological behaviors and biogeochemical cycles across diverse temporal and spatial scales. The Tibetan Plateau provides an ideal setting for investigating the interactions between hydrological and geomorphic processes in a largely pristine natural environment. Nonetheless, the interactions remain largely unknown due to challenging physical conditions and data limitations. This study presents the inaugural version of a hydrogeomorphic dataset encompassing 18 440 catchments across the region. The dataset comprises 18 hydrogeomorphic metrics along with, in particular, the width-function-based instantaneous unit hydrograph (WFIUH) of each catchment. We find that the peak flow of WFIUH is positively related to slope and curvature but negatively related to catchment area, perimeter, length and circularity. The relationships of time to peak with the hydrogeomorphic metrics are similar to those of peak flow but in an oppositive direction. Catchment concentration time shows a positive relationship with catchment size but a strong negative correlation with catchment slope. The validity of the derived WFIUH has been confirmed by its successful integration into an hourly hydrological model for simulating flash-flood events. Uncertainties in the WFIUH can be attributed to the resolution of the digital elevation model (DEM) and the methods employed for calculating flow velocity. The dataset is publicly available via the Zenodo portal: https://doi.org/10.5281/zenodo.8280786 (Guo and Zheng, 2023). It can contribute to advancing our understanding of catchment hydrological behaviors and can provide simple and fast-routing unit hydrograph calculation for ungauged catchments in the Tibetan Plateau and hence improve water resources management and disaster mitigation in the region and its downstream areas.
DCMIP2016: the tropical cyclone test case
Authors: Willson Justin L. , Reed Kevin A. , Jablonowski Christiane , Kent James , Lauritzen Peter H. , Nair Ramachandran , Taylor Mark A. , Ullrich Paul A. , Zarzycki Colin M. , Hall David M. , Dazlich Don , Heikes Ross , Konor Celal , Randall David , Dubos Thomas , Meurdesoif Yann , Chen Xi , Harris Lucas , Kühnlein Christian , Lee Vivian , Qaddouri Abdessamad , Girard Claude , Giorgetta Marco , Reinert Daniel , Miura Hiroaki , Ohno Tomoki , Yoshida Ryuji
Published: April 2024

Abstract. This paper describes and analyzes the Reed–Jablonowski (RJ) tropical cyclone (TC) test case used in the 2016 Dynamical Core Model Intercomparison Project (DCMIP2016). This intermediate-complexity test case analyzes the evolution of a weak vortex into a TC in an idealized tropical environment. Reference solutions from nine general circulation models (GCMs) with identical simplified physics parameterization packages that participated in DCMIP2016 are analyzed in this study at 50 km horizontal grid spacing, with five of these models also providing solutions at 25 km grid spacing. Evolution of minimum surface pressure (MSP) and maximum 1 km azimuthally averaged wind speed (MWS), the wind–pressure relationship, radial profiles of wind speed and surface pressure, and wind composites are presented for all participating GCMs at both horizontal grid spacings. While all TCs undergo a similar evolution process, some reach significantly higher intensities than others, ultimately impacting their horizontal and vertical structures. TCs simulated at 25 km grid spacings retain these differences but reach higher intensities and are more compact than their 50 km counterparts. These results indicate that dynamical core choice is an essential factor in GCM development, and future work should be conducted to explore how specific differences within the dynamical core affect TC behavior in GCMs.