Atmospheric System Research Articles

Decomposing the effective radiative forcing of anthropogenic aerosols based on CMIP6 Earth system models

Abstract. Anthropogenic aerosols play a major role in the Earth–atmosphere system by influencing the Earth's radiative budget and precipitation and consequently the climate. The perturbation induced by changes in anthropogenic aerosols on the Earth's energy balance is quantified in terms of the effective radiative forcing (ERF). In this work, the present-day shortwave (SW), longwave (LW), and total (i.e., SW plus LW) ERF of anthropogenic aerosols is quantified using two different sets of experiments with prescribed sea surface temperatures (SSTs) from Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6): (a) time-slice pre-industrial perturbation simulations with fixed SSTs (piClim) and (b) transient historical simulations with time-evolving SSTs (histSST) over the historical period (1850–2014). ERF is decomposed into three components for both piClim and histSST experiments: (a) ERFARI, representing aerosol–radiation interactions; (b) ERFACI, accounting for aerosol–cloud interactions (including the semi-direct effect); and (c) ERFALB, which is due to temperature, humidity, and surface albedo changes caused by anthropogenic aerosols. We present spatial patterns at the top-of-atmosphere (TOA) and global weighted field means along with inter-model variability (1 standard deviation) for all SW, LW, and total ERF components (ERFARI, ERFACI, and ERFALB) and for every experiment used in this study. Moreover, the inter-model agreement and the robustness of our results are assessed using a comprehensive method as utilized in the IPCC Sixth Assessment Report. Based on piClim experiments, the total present-day (2014) ERF from anthropogenic aerosol and precursor emissions is estimated to be −1.11 ± 0.26 W m−2, mostly due to the large contribution of ERFACI to the global mean and to the inter-model variability. Based on the histSST experiments for the present-day period (1995–2014), similar results are derived, with a global mean total aerosol ERF of −1.28 ± 0.37 W m−2 and dominating contributions from ERFACI. The spatial patterns for total ERF and its components are similar in both the piClim and histSST experiments. Furthermore, implementing a novel approach to determine geographically the driving factor of ERF, we show that ERFACI dominates over the largest part of the Earth and that ERFALB dominates mainly over the poles, while ERFARI dominates over certain reflective surfaces. Analysis of the inter-model variability in total aerosol ERF shows that SW ERFACI is the main source of uncertainty predominantly over land regions with significant changes in aerosol optical depth (AOD), with eastern Asia contributing mostly to the inter-model spread of both ERFARI and ERFACI. The global spatial patterns of total ERF and its components from individual aerosol species, such as sulfates, organic carbon (OC), and black carbon (BC), are also calculated based on piClim experiments. The total ERF caused by sulfates (piClim-SO2) is estimated at −1.11 ± 0.31 W m−2, and the OC ERF (piClim-OC) is −0.35 ± 0.21 W m−2, while the ERF due to BC (piClim-BC) is 0.19 ± 0.18 W m−2. For sulfates and OC perturbation experiments, ERFACI dominates over the globe, whereas for BC perturbation experiments ERFARI dominates over land in the Northern Hemisphere and especially in the Arctic. Generally, sulfates dominate ERF spatial patterns, exerting a strongly negative ERF especially over industrialized regions of the Northern Hemisphere (NH), such as North America, Europe, and eastern and southern Asia. Our analysis of the temporal evolution of ERF over the historical period (1850–2014) reveals that ERFACI clearly dominates over ERFARI and ERFALB for driving the total ERF temporal evolution. Moreover, since the mid-1980s, total ERF has become less negative over eastern North America and western and central Europe, while over eastern and southern Asia there is a steady increase in ERF magnitude towards more negative values until 2014.

Unveiling a new oceanic anoxic event at the Norian/Rhaetian boundary (Late Triassic)

The latest Triassic was characterised by protracted biotic extinctions concluding in the End-Triassic Extinction (~ 200 Ma) and a global carbon cycle perturbation. The onset of declining diversity is closely related to reducing conditions that spread globally from upper Sevatian (uppermost Norian) to across the Norian-Rhaetian boundary, likely triggered by unusually high volcanic activity. We correlate significant organic carbon cycle perturbations to an increase of CO2 in the ocean–atmosphere system, likely outgassed by the Angayucham igneous province, the onset of which is indicated by the initiation of a rapid decline in 87Sr/86Sr and 188Os/187Os seawater values. A possible causal mechanism involves elevated CO2 levels causing global warming and accelerating chemical weathering, which increased nutrient discharge to the oceans and greatly increased biological productivity. Higher export production and oxidation of organic matter led to a global O2 decrease in marine water across the Norian/Rhaetian boundary (NRB). Biotic consequences of dysoxia/anoxia include worldwide extinctions in some fossil groups, such as bivalves, ammonoids, conodonts, radiolarians.

Estimation of mean electron energy in helium surface ionization waves on dielectric substrates

The determination of basic plasma parameters in atmospheric pressure discharges is critical to advancing their use in applications. Atmospheric pressure plasma jets have found use in the fields of medicine, agriculture, material modification and others. Atmospheric pressure plasma jets often generate plasma surface ionization waves (SIW) which interact with and propagate over surfaces. Electrical diagnostics are challenging in SIW due to high collision frequencies and small scale of the plasma discharge. This work employs a passive optical emission line ratio technique to estimate the mean electron energy in SIW over planar dielectric substrates. The method uses an intensity ratio of two helium triplet lines: He( 33S ) at 706.5 nm and He( 33D ) at 587.56 nm. A collisional-radiative model is used to correlate line ratio to mean electron energy and determine dependencies on electron density and He/air gas mixture. Mean electron energies ranging from 3–8 eV are determined in He/air mixtures and are found to remain constant as the surface wave propagates radially. This work provides a 2D, time-resolved, mean electron energy diagnostic for surface ionization wave propagation and validation of numerical modeling in atmospheric pressure systems with spatially varying He/air gas mixtures. The model in question is designed for use with any He line ratio in the n = 3 excitation level.

Provenance and Fluvial‐Aeolian Process of Kyzylkum Desert: Constrained by Detrital Zircon U–Pb Dating

AbstractThe Kyzylkum Desert, as a transition area of different dust source in Central Asia, provides and reserves a large amount of dust transported by different atmospheric circulation systems, affecting Uzbekistan and downwind East Asia. However, there remains very few investigations about sediment sources and control factors of the desert. We hereby first present a provenance study on the Kyzylkum Desert, utilizing detrital zircon U‐Pb ages of samples composed of desert sand, alluvial sediments from Amu Darya River and piedmont of Southwest Tianshan Mountains. The results reveal that the Southwest Tianshan Mountains contribute the majority of the Kyzylkum desert sand, and the river system, dominated by Syr Darya, controls the sediment provenance of the desert. Moreover, little contribution from the Kyzylkum and Nurata segments indicates that wind erosion on the bedrocks is weak. However, the aeolian process is still crucial but deposit and storage of dust are determined by local topography.

Spin–momentum properties in the gradient-index fiber

The vector characteristics of the kinetic momentum, spin angular momentum (SAM), and light field of a radially polarized vortex beam (RPVB) in the radial gradient-index (GRIN) fiber are analyzed using a unified methodology based on the generalized Huygens-Fresnel principle and the spin-momentum relationship. The kinetic momentum, SAM, transverse-type spin (t-SAM), longitudinal-type spin (l-SAM) and light field contain parallel and perpendicular components to the optical axis in the GRIN fiber. Moreover, the optical spin skyrmion from the SAM, t-SAM, and l-SAM can be observed at the semi-focal plane and the focal plane of the GRIN fiber. To the best of our knowledge, this is the first confirmation of spin skyrmions in the GRIN fiber. The analysis of spin-momentum properties of an RPVB in the GRIN fiber combined with the generalized Huygens-Fresnel principle and the spin-momentum relationship can be applied in describing the vector properties of transmission in atmospheric and optical systems.

Investigating the spatial propagation patterns of meteorological drought events and underlying mechanisms using complex network theory: A case study of the Yangtze River Basin, China

The spatial propagation patterns of meteorological drought events (MDEs) and underlying mechanisms contribute to elucidating and forecasting drought evolution. In this study, gridded MDEs in the Yangtze River Basin (YRB) throughout the entire year, wet season and dry season were extracted from 3-month Standardized Precipitation Evapotranspiration Index (SPEI-3) series. Event synchronization (ES) and complex networks (CN) were employed to construct the MDE synchronization networks and MDE spatial propagation networks for various periods. The former were utilized to identify MDE synchronized subregions where MDEs co-occur and co-evolve in the YRB, while the latter were used to quantify the MDE spatial propagation patterns over both the basin and its subregions. The driving mechanisms behind MDE spatial propagation were further investigated by diagnosing the concomitant drought-inducing climate systems. The findings reveal the presence of four MDE synchronized subregions during the wet season and five subregions during the entire year and dry season. These subregions exhibited distinct spatial propagation patterns of MDEs, aligning with overall findings across the YRB. Notable differences were observed between wet and dry seasons, with various subregions exhibiting distinctive spatial propagation patterns during each season. These patterns are driven by variations in the controlling atmospheric circulation systems, leading to anomalies of wind patterns and moisture distribution, ultimately resulting in deficient moisture supply. The variations of tropical sea surface thermal conditions, influences of the Tibetan Plateau and MDE self-propagation triggered by land–atmosphere feedback are considered as three primary influencing factors for MDE spatial propagation in the YRB.

Hydro-meteorological aspects of soil fluorides in semi-arid soils using microwave remote sensing.

Soil fluoride is a critical determinant of soil fertility, human health and crop productivity. Soil fluoride can be increased by climatic conditions, irrigation water and anthropogenic activity, and it is important to control fluoride by understanding the complex relationships between atmospheric conditions and water systems. In this research, a detailed focus is on the hydrological and meteorological aspects of soil fluorides in semi-saturated and saturated soils to discuss the impact of irrigation, capillary rise and the combination of rainfall and anthropogenic activities such as fertilizer application on the soils in the dry spell and monsoon seasons of 2021 and 2022. A Sentinel-1 data can be used to estimate fluoride levels to the above soil conditions. In an effort to estimate fluoride levels in different hydro-meteorological scenarios, we have put forward a hypothesis that focuses on understanding the potential connections between hydro-meteorological factors (precipitation, groundwater levels, and temperature) and the levels of fluoride. The findings indicate that the extensive use of groundwater for irrigation leads to a rise in fluoride levels, posing a significant threat to crop health over time. Furthermore, the combined effects of irrigation and upheaval leaching on fluoride levels have shown strong statistical conformity (R2 > 0.85) with the relevant field-measured fluoride data for the year 2022. Importantly, areas affected by are more sensitive to the sand and clay percentage in the soil because potential and dispersion behaviour enlarge the capillaries to decelerate the upward movement. A region-based discussion details the factors contributing to the increase of fluoride in soil helpful in taking remedial measures and mitigation plans.

Continuous ion beam-induced luminescence (IBIL) spectroscopy of air-borne particulate matter hourly collected from the atmosphere

We investigated the applicability of Ion Beam Induced Luminescence (IBIL) analysis for identifying biological components in sequentially collected airborne particulate matter (PM) samples obtained using the automated sampler. A series of micro-IBIL spectroscopies were performed on a PTFE (polytetrafluoroethylene) membrane tape filter from the Atmospheric Environmental Regional Observation System (AEROS) during a highly concentrated air pollution event on 26–27 March 2020, collected at Ota, Japan (36.290°n, 139.381°e) using an external 3 MeV proton microprobe. IBIL at typical wavelengths associated with organic compounds such as NADH and riboflavin were identified through the series of IBIL analyses, which is a key factor for identifying existence of organic pollutions, or bioaerosols. The decay times of the IBIL indicate that the peak measured is due to organic compounds rather than inorganic particles or ambient substances. These results suggest that micro-IBIL spectroscopy can be used to identify bioaerosols in hourly collected AEROS PTFE membrane tape filters taken from the atmosphere.

Regulating the Transfer of Photogenerated Carriers for Photocatalytic Hydrogen Evolution Coupled with Furfural Synthesis.

How to simultaneously utilize photogenerated electrons and holes still remains a critical challenge in the field of artificial photosynthesis, especially in the process of photocatalytic hydrogen (H2) evolution coupled with biomass oxidation to value-added chemicals. Herein, a series-parallel photocatalyst (Cu NPs/CdS/In2O3) that can intrinsically regulate the transfer of photogenerated carriers is ingeniously designed for photocatalytic H2 evolution synergized with furfural alcohol (FFA) selective oxidation to furfural (FF). Accordingly, the desired H2 and FF evolution rates with near 100% selectivity toward FF are achieved on Cu NPs/CdS/In2O3 in a sealed atmospheric system. Experimental and theoretical analyses confirm that the localized surface plasmon resonance (LSPR) effect induced by Cu NPs accelerates the reduction of protons (H+) to H2 efficiently, while the photogenerated holes from In2O3 preferentially activate the α-C-H bond of FFA adsorbed on Lewis acid sites to generate FF. This work provides a reference for regulating the transfer of photogenerated carriers for H2 evolution coupled with FF synthesis.

Negative storm surges in the Río de la Plata Estuary: mechanisms, variability, trends and linkage with the Continental Shelf dynamics

Negative storm surge (NSS) events frequently affect the Río de la Plata Estuary (RdP), limiting the access to major ports and waterways and emptying the freshwater intakes of one of the most socially developed basins of the Southwestern Atlantic Continental Shelf (SWACS). It is important to re-examine this issue, as the available studies are outdated, there are some contradictions in the literature and a regional framework of the adjacent shelf dynamics is not yet available. In this work (i) nonlinear statistical analyses were applied to review and update the climatological description of NSS in the RdP; and, then, (ii) an ocean numerical model was employed to describe and understand the surge dynamics framed into the larger scale dynamics of the atmospherically forced SWACS. An analysis of 87 years of hourly residual sea level observations (RSL) reveals that the number of yearly NSS events time series presents (i) a statistically significant multidecadal non-linear trend or envelope and (ii) two significant pseudo-cycles centred at 3.5 and 11.5 years that explain a large fraction of the interannual variability embedded in the multidecadal modulation.Numerical simulations results show that the surges (both negative and positive) that are generated in the SWACS and reach the RdP result from the passage of atmospheric planetary waves over Patagonia which produce winds with a significant alongshore (N-S) component. These winds force an Ekman transport either offshore or onshore at the coast, generating a negative or positive sea level anomaly, which will be larger as the atmospheric system is slower and more persistent. When synoptic atmospheric systems migrate away from the coast on their northeastward propagation, the forced sea level anomalies propagate along the coast to the north as free Kelvin waves, eventually reaching the estuary; thus the forcing for surges at the RdP can be remote. In this sense, despite the large gulfs and bays, the response of the Patagonian coast is similar to that of a linear coastline oriented in a north–south direction. In addition to remotely forced surges, locally forced events occur in the RdP as a result of the estuarine geometry and its resonant response to winds with a component longitudinal to the estuary axis (NW-SE), which could be forced by other atmospheric configurations besides Rossby waves, such as cyclogenesis of the Argentine Littoral.

A global surface CO2 flux dataset (2015–2022) inferred from OCO-2 retrievals using the GONGGA inversion system

Abstract. Accurate assessment of the size and distribution of carbon dioxide (CO2) sources and sinks is important for efforts to understand the carbon cycle and support policy decisions regarding climate mitigation actions. Satellite retrievals of the column-averaged dry-air mole fractions of CO2 (XCO2) have been widely used to infer spatial and temporal variations in carbon fluxes through atmospheric inversion techniques. In this study, we present a global spatially resolved terrestrial and ocean carbon flux dataset for 2015–2022. The dataset was generated by the Global ObservatioN-based system for monitoring Greenhouse GAses (GONGGA) atmospheric inversion system through the assimilation of Orbiting Carbon Observatory-2 (OCO-2) XCO2 retrievals. We describe the carbon budget, interannual variability, and seasonal cycle for the global scale and a set of TransCom regions. The 8-year mean net biosphere exchange and ocean carbon fluxes were −2.22 ± 0.75 and −2.32 ± 0.18 Pg C yr−1, absorbing approximately 23 % and 24 % of contemporary fossil fuel CO2 emissions, respectively. The annual mean global atmospheric CO2 growth rate was 5.17 ± 0.68 Pg C yr−1, which is consistent with the National Oceanic and Atmospheric Administration (NOAA) measurement (5.24 ± 0.59 Pg C yr−1). Europe has the largest terrestrial sink among the 11 TransCom land regions, followed by Boreal Asia and Temperate Asia. The dataset was evaluated by comparing posterior CO2 simulations with Total Carbon Column Observing Network (TCCON) retrievals as well as Observation Package (ObsPack) surface flask observations and aircraft observations. Compared with CO2 simulations using the unoptimized fluxes, the bias and root mean square error (RMSE) in posterior CO2 simulations were largely reduced across the full range of locations, confirming that the GONGGA system improves the estimates of spatial and temporal variations in carbon fluxes by assimilating OCO-2 XCO2 data. This dataset will improve the broader understanding of global carbon cycle dynamics and their response to climate change. The dataset can be accessed at https://doi.org/10.5281/zenodo.8368846 (Jin et al., 2023a).

Editorial preface to special issue: Cenozoic climate change in Asia in honour of Prof. Zhengtang Guo

The Asian monsoon has progressively become a megamonsoon system since the early Cenozoic. To improve our understanding of the complex nature of the Asian monsoon system, involving strong interactions between atmospheric, oceanic and terrestrial systems across different timescales, we present this special issue, entitled Cenozoic climate change in Asia. The special issue is dedicated to Prof. Zhengtang Guo in honour of his distinguished contributions as Editor-in-Chief of Global and Planetary Change to our understanding of the long-term evolution of the Asian monsoon system. The special issue consists of nineteen papers, grouped into three categories, that address Cenozoic climate change, mainly in Asia. The first category focuses on the plate tectonic-scale and considers how changes in palaeogeography and palaeotopography have shaped climate evolution. The second category addresses orbital- to suborbital-scale climate change and, in particular, explores the links between low-latitude insolation, high-latitude ice sheets and the Asian climate. The third category addresses millennial- to decadal-scale climate changes. In addition, past human-environment interactions are also discussed. These studies provide important insights into our understanding and prediction of both natural variability and human-induced climate changes in Asia and their linkages with global climate within the Earth System.

Multiparameter Detection of Summer Open Fire Emissions: The Case Study of GAW Regional Observatory of Lamezia Terme (Southern Italy)

In Southern Mediterranean regions, the issue of summer fires related to agriculture practices is a periodic recurrence. It implies a significant increase in carbon dioxide (CO2) emissions and other combustion-related gaseous and particles compounds emitted into the atmosphere with potential impacts on air quality and global climate. In this work, we performed an analysis of summer fire events that occurred on August 2021. Measurements were carried out at the permanent World Meteorological Organization (WMO)/Global Atmosphere Watch (GAW) station of Lamezia Terme (Code: LMT) in Calabria, Southern Italy. The observatory is equipped with greenhouse gases and black carbon analyzers, an atmospheric particulate impactor system, and a meteo-station for atmospheric parameters to characterize atmospheric mechanisms and transport for land and sea breezes occurrences. High mole fractions of carbon monoxide (CO) and carbon dioxide (CO2) coming from quadrants of inland areas were correlated with fire counts detected via the MODIS satellite (GFED-Global Fire Emissions Database) at 1 km of spatial resolution. In comparison with the typical summer values, higher CO and CO2 were observed in August 2021. Furthermore, the growth in CO concentration values in the tropospheric column was also highlighted by the analyses of the L2 products of the Copernicus SP5 satellite. Wind fields were reconstructed via a Weather Research and Forecasting (WRF) output, the latter suggesting a possible contribution from open fire events observed at the inland region near the observatory. So far, there have been no documented estimates of the effect of prescribed burning on carbon emissions in this region. This study suggested that data collected at the LMT station can be useful in recognizing and consequently quantifying emission sources related to open fires.

The effects of climate warming on large-scale atmospheric systems of the Northern Hemisphere

The effects of climate warming on large-scale atmospheric systems of the Northern Hemisphere

Crucial role of sea surface temperature warming patterns in near-term high-impact weather and climate projection

Recent studies indicate that virtually all global climate models (GCMs) have had difficulty simulating sea surface temperature (SST) trend patterns over the past four decades. GCMs produce enhanced warming in the eastern Equatorial Pacific (EPAC) and Southern Ocean (SO) warming, while observations show intensified warming in the Indo-Pacific Warm Pool (IPWP) and slight cooling in the eastern EPAC and SO. Using Geophysical Fluid Dynamics Laboratory’s latest higher resolution atmospheric model and coupled prediction system, we show the model biases in SST trend pattern have profound implications for near-term projections of high-impact storm statistics, including the frequency of atmospheric rivers (AR), tropical storms (TS) and mesoscale convection systems (MCS), as well as for hydrological and climate sensitivity. If the future SST warming pattern continues to resemble the observed pattern from the past few decades rather than the GCM simulated/predicted patterns, our results suggest (1) a drastically different future projection of high-impact storms and their associated hydroclimate changes, especially over the Western Hemisphere, (2) a stronger global hydrological sensitivity, and (3) substantially less global warming due to stronger negative feedback and lower climate sensitivity. The roles of SST trend patterns over the EPAC, IPWP, SO, and the North Atlantic tropical cyclone Main Development Region (AMDR) are isolated, quantified, and used to understand the simulated differences. Specifically, SST trend patterns in the EPAC and AMDR are crucial for modeled differences in AR and MCS frequency, while those in the IPWP and AMDR are essential for differences in TS frequency over the North Atlantic.

Effective attention model for global sea surface temperature prediction

Sea Surface Temperature (SST) is an essential parameter of the ocean–atmosphere system, so accurately predicting the future SST is of great significance. To address the low prediction accuracy due to insufficient consideration of spatiotemporal correlations in existing machine learning models, this paper proposes an Effective Attention Model (EAM) to achieve daily global SST prediction (predicting the SST of the next 15 days using those of the past 15 days) and monthly global SST prediction (predicting the SST of the next 12 months using those of the past 12 months). The EAM adopts an attention mechanism to avoid information redundancy and improve prediction accuracy. This is the first work to realize high-accuracy global SST prediction with a high spatial resolution of 0.25° on two time scales (daily and monthly) based on deep learning. Experiments show that (1) the prediction results have a consistent global spatiotemporal distribution with the ground truth, with the Root Mean Squared Difference (RMSD) of daily prediction ranging from 0.212 to 0.932 ℃ and the RMSD of monthly prediction ranging from 0.666 to 0.782 ℃. The EAM is superior to the deep learning models (ConvLSTM, 3D-CNN, and LSTM) and the numerical model (HYCOM); (2) Besides global prediction, the EAM also achieves good performance in a climate change sensitive area (Niño 3.4 sea area), with the lowest RMSD of 0.231 ℃. This study may not only benefit the research on climate events (El Niño and La Niña) but also serve to predict other marine disasters (such as heat waves and storms). In the future, the proposed attention module can also be adapted to other prediction scenarios such as meteorology.

Використання комплексу газогрунтової зйомки та геофізичних досліджень у задачі окреслення території грязьового вулканізму в межах Розвадівської площі Львівської області

The purpose of the research was to substantiate the scientific basis behind the formation of a mud volcano within a specific section of the Precarpathian depression. It also aims to examine the existence of a near-fault shallow gas deposit in the Rozvadiv area and its possible impact on gas-soil surveying and electrometry fields. The relevance of the work is determined by the need to solve the ecological problem of environmental pollution with hydrocarbon gases, as well as to establish and forecast the degree of emissions of the gas-mud mixture. At the same time, the problem of the presence (or absence) of the relationship between the influence of the Rudnyk gas-prospecting area, which is impacted by drilling, and the Rozvadiv deposit mentioned above is solved by comparing the results of gas-soil and geophysical surveys on a significant territory covering the specified areas. The research methodology consists of the following: 1) application of research with different physical justifications (gas-soil survey and electrometry); 2) comparison of the survey results from the same area and the same grid of observations; 3) detection of anomalies within the studied territory and their interpretation from the point of view of the development of mud volcanism. Research results. The information basis of gasometry involves direct measurements of free gas in a observation regular system in the soil environment atmosphere, their statistical characteristics, and calculated indicators of gas contamination. Therefore, the gas distribution maps are informative. The applied research using the method of Earth’s natural pulsed electromagnetic field made it possible to differentiate the area according to the intensity degree of electromagnetic radiation, taking into account the different depths of the sources, and, thus, identify areas of stressed-strain state of rocks and qualify them by the causes. The scientific novelty lies in the following: 1) indicating the absence of connections between the massif impacted by drilling and a natural disaster; 2) specifying the causes of the natural disaster and its substantiated mechanism and classifying the event as a mud volcano. Practical significance. Interpretation of the obtained results makes it possible to determine the causes of the extraordinary geological event in the Rozvadiv area of the Lviv region, classify the event and its consequences as a manifestation of elements of mud volcanism, and establish the absence of a relationship between the specified event and man-made impact (drilling) of the geological environment in the neighbouring areas.

Implementation and Exploration of Parameterizations of Large‐Scale Dynamics in NCAR's Single Column Atmosphere Model SCAM6

AbstractA single column model with parameterized large‐scale (LS) dynamics is used to better understand the response of steady‐state tropical precipitation to relative sea surface temperature under various representations of radiation, convection, and circulation. The large‐scale dynamics are parametrized via the weak temperature gradient (WTG), damped gravity wave (DGW), and spectral weak temperature gradient (Spectral WTG) method in NCAR's Single Column Atmosphere Model (SCAM6). Radiative cooling is either specified or interactive, and the convective parameterization is run using two different values of a parameter that controls the degree of convective inhibition. Results are interpreted in the context of the Global Atmospheric System Studies ‐Weak Temperature Gradient (GASS‐WTG) Intercomparison project. Using the same parameter settings and simulation configuration as in the GASS‐WTG Intercomparison project, SCAM6 under the WTG and DGW methods produces erratic results, suggestive of numerical instability. However, when key parameters are changed to weaken the large‐scale circulation's damping of tropospheric temperature variations, SCAM6 performs comparably to single column models in the GASS‐WTG Intercomparison project. The Spectral WTG method is less sensitive to changes in convection and radiation than are the other two methods, performing qualitatively similarly across all configurations considered. Under all three methods, circulation strength, represented in 1D by grid‐scale vertical velocity, is decreased when barriers to convection are reduced. This effect is most extreme under specified radiative cooling, and is shown to come from increased static stability in the column's reference radiative‐convective equilibrium profile. This argument can be extended to interactive radiation cases as well, though perhaps less conclusively.

An analysis of parameters affecting ampacity in aircraft bipolar MVDC power cables via coupled electrical, thermal, and computational fluid dynamic modelling

AbstractThe next generation of aircraft, including more electric aircraft and all‐electric aircraft, require electric power systems with high power density and low system mass specifications. Increasing the voltage of the system to the range of a few kV, medium voltage (MV), is a reasonable approach to achieving high‐power‐density and low‐system‐mass EPSs for aircraft applications. Higher voltages, however, pose many challenges for aviation MV power cables such as arcs and arc tracking, partial discharges (PDs), and thermal management. In this regard, thermal management is more challenging since heat transfer by convection is greatly reduced at wide‐body aircraft's cruising altitudes due to the reduced air pressure. In this paper, a finite element method (FEM) model is developed in COMSOL Multiphysics for an aircraft bipolar MVDC (±5 kV) power cable. Using the model, the maximum permissible cable current at a low pressure of 18.8 kPa (at an altitude of 12.2 km from sea level, the usual cruising altitude for wide‐body aircraft) is calculated. Also, an analytical model is developed based on analytical and proven empirical correlations governing conductive, radiative, and convective heat transfers at the steady state to estimate the ampacity of the bipolar cable system at reduced pressure. It was shown that the proposed analytical model can be used for atmospheric pressure and systems with a larger number of poles, expanding its range of applications. The results of the FEM and analytical models correlate at wide ranges of parameters such as ambient temperature, duct size, distance between the positive and negative pole cables, and the overall diameter of the cables. The influence of horizontal and vertical arrangement of poles is included in the analytical model. The results of this study can be used to design bipolar MVDC power cable systems for the envisaged wide‐body AEA.

Enhancing biodegradable polymer surface wettability properties through atmospheric plasma treatmsurfaent and nanocellulose incorporation

This study investigates the effects of atmospheric plasma treatment on the surface properties of polylactic acid (PLA)/nanocrystalline cellulose (CNC) composites, aiming to improve their wettability and mechanical properties. The research utilizes a twin-screw extrusion process for fabricating PLA/CNC biocomposites, followed by surface modification using a custom-built, with a tenfold high-voltage atmospheric plasma system. The motivation of this treatment was to improved surface wettability and potential for enhanced adhesive bonding in ecological applications. These findings contribute to developing more sustainable composite materials by providing a method to improve the functionality of biodegradable polymers without compromising their environmental benefits.