Atmospheric Velocity Research Articles

Suppression of photospheric velocity fluctuations in strongly magnetic O stars in radiation-magnetohydrodynamic simulations

O stars generally show clear signs of strong line broadening (in addition to rotational broadening) in their photospheric absorption lines (typically referred to as macroturbulence), believed to originate in a turbulent sub-surface zone associated with enhanced opacities due to the recombination of iron-group elements (at T ∼ 150-200 kK). O stars with detected global magnetic fields also display such macroturbulence; the sole exception to this is NGC 1624-2, which also has the strongest (by far) detected field of the known magnetic O stars. It has been suggested that this lack of additional line broadening is due to NGC 1624-2's exceptionally strong magnetic field, which might be able to suppress the turbulent velocity field generated in the iron opacity peak zone. We tested this hypothesis based on two-dimensional (2D), time-dependent, radiation magnetohydrodynamical (RMHD) box-in-a-star simulations for O stars that encapsulate the deeper sub-surface atmosphere (down to T ∼ 400 kK), the stellar photosphere, and the onset of the supersonic line-driven wind in one unified approach. To study the potential suppression of atmospheric velocity fluctuations, we extended our previous non-magnetic O star radiation-hydrodynamic (RHD) simulations to include magnetic fields of varying strengths and orientations. We used MPI-AMRVAC which is a Fortran 90 based publically available parallel finite volume code that is highly modular. We used the recently added RMHD module to perform all our simulations here. For moderately strong magnetic cases (∼ 1 kG), the simulated atmospheres are highly structured and characterised by large root-mean-square velocities, and our results are qualitatively similar to those found in previous non-magnetic studies. By contrast, we find that a strong horizontal magnetic field in excess of 10 kG can indeed suppress the large velocity fluctuations, and can thus stabilise (and thereby also inflate) the atmosphere of a typical early O star in the Galaxy. On the other hand, an equally strong radial field is only able to suppress horizontal motions, and as a consequence these models exhibit significant radial fluctuations. Our simulations provide an overall physical rationale as to why NGC 1624-2 with its strong ∼ 20 kG dipolar field lacks the large macroturbulent line broadening that all other known slowly rotating early O stars exhibit. However, our simulations also highlight the importance of field geometry for controlling the atmospheric dynamics in massive and luminous stars that are strongly magnetic, tentatively suggesting latitudinal dependence of macroturbulence and basic photospheric parameters.

Identifying the onset and decay of quasi-stationary families of almost-invariant sets with an application to atmospheric blocking events.

Macroscopic features of dynamical systems such as almost-invariant sets and coherent sets provide crucial high-level information on how the dynamics organizes phase space. We introduce a method to identify time-parameterized families of almost-invariant sets in time-dependent dynamical systems, as well as the families' emergence and disappearance. In contrast to coherent sets, which may freely move about in phase space over time, our technique focuses on families of metastable sets that are quasi-stationary in space. Our straightforward approach extends successful transfer operator methods for almost-invariant sets to time-dependent dynamics and utilizes the Ulam scheme for the generator of the transfer operator on a time-expanded domain. The new methodology is illustrated with an idealized fluid flow and with atmospheric velocity data. We identify atmospheric blocking events in the 2003 European heatwave and compare our technique to existing geophysical methods of blocking diagnosis.

Magnetohydrodynamic and Aerodynamic Assessment of a 70° Spherecone at Mars and Venus

An electrical conductivity database for continuum flow in a CO2 atmosphere over a 70° spherecone was created using the Data Parallel Line Relaxation Code computational fluid dynamics software to inform development of future magnetohydrodynamic subsystems at Venus and Mars. Sixteen freestream conditions were considered at Mars with atmospheric relative velocities from 5 to 8 km/s and altitudes between 20 and 80 km. Sixteen freestream conditions were considered at Venus with atmospheric relative velocities from 9 to 12 km/s and altitudes between 85 and 115 km. Results indicate that the total electrical conductivity in the flow volume always increases as velocity increases. At low velocities, the electrical conductivity is higher at high altitudes whereas, at high velocities, the electrical conductivity is higher at low altitudes. Three of the 80 km altitude computational fluid dynamics solutions show good agreement with direct simulation Monte Carlo results. In general, computational fluid dynamics predicts thinner shocks, higher electron number density, and similar vibrational temperatures to direct simulation Monte Carlo. The magnetohydrodynamic force was calculated at both Mars and Venus. Results indicate there may not be sufficient control authority to use magnetohydrodynamics as a trajectory control mechanism at Mars without artificially increasing the electrical conductivity of the flow, but there may be appreciable control authority for a drag-modulated aerocapture at Venus.

The Korean infrasound catalogue (1999–2022)

SUMMARY The Korean infrasound catalogue (KIC) covers 1999–2022 and characterizes a rich variety of source types as well as document the effects of the time-varying atmosphere on event detection and location across the Korean Peninsula. The KIC is produced using data from six South Korean infrasound arrays that are cooperatively operated by Southern Methodist University and Korea Institute of Geoscience and Mineral Resources. Signal detection relies on an Adaptive F-Detector that estimates arrival time and backazimuth, which draws a distinction between detection and parameter estimation. Detections and associated parameters are input into a Bayesian Infrasonic Source Location procedure. The resulting KIC contains 38 455 infrasound events and documents repeated events from several locations. The catalogue includes many anthropogenic sources such as an industrial chemical explosion, explosions at limestone open-pit mines and quarries, North Korean underground nuclear explosions and other atmospheric or underwater events of unknown origin. Most events in the KIC occur during working hours and days, suggesting a dominance of human-related signals. The expansion of infrasound arrays over the years in South Korea and the inclusion of data from the International Monitoring System infrasound stations in Russia and Japan increase the number of infrasound events and improve location accuracy because of the increase in azimuthal station coverage. A review of selected events and associated signals at multiple arrays provides a location quality assessment. We quantify infrasound events that have accompanying seismic arrivals (seismoacoustic events) to support the source type assessment. Ray tracing using the Ground-to-Space (G2S) atmospheric model generally predicts observed arrivals when strong stratospheric winds exist, although the predicted arrival times have significant discrepancies. In some cases, local atmospheric data better captures small-scale variations in the wind velocity of the shallow atmosphere and can improve arrival time predictions that are not well matched by the G2S model. The analysis of selected events also illustrates the importance of topographic effects on tropospheric infrasound propagation at local distances. The KIC is the first infrasound catalogue compiled in this region, and it can serve as a valuable data set in developing more robust infrasound source localization and characterization methods.

Conceptual design and optimization of heat rejection system for nuclear reactor coupled with supercritical carbon dioxide Brayton cycle used on Mars

During the conceptual design of the Mars surface nuclear reactor coupled with supercritical carbon dioxide Brayton cycle, the heat rejection system occupies most of the weight, and reducing the weight of heat rejection system can effectively cut down the transportation cost from Earth to Mars. This paper explored the feasibility of adopting a combination of heat pipe cooling device and convective heat exchanger to design the heat rejection system for the Mars surface nuclear power station, established flow and heat transfer model and weight model, developed a thermal-hydraulic design program for the heat rejection system, and verified its accuracy; then, the NSGA-II multi-objective optimization method is used to optimize the weight of heat rejection system. Pareto front shows that with higher heat rejection proportion of convective heat exchanger, corresponding inlet velocity of Mars' atmosphere should also be increased. As the optimization result of heat rejection system, the ratio of weight to heat rejection is between 0.94 kg/kW and 2.92 kg/kW, and the maximum power consumption of convective heat exchanger accounts for 3.29% of the total power generation.

HYBRID MODEL AND FRAMEWORK FOR PREDICTING AIR POLLUTANTS IN SMART CITIES

The pollution index of any urban area is indicated by its air quality. It also shows a fine balance is maintained between the needs of the populace and the industrial ecosystem. To mitigate such pollution in real-time, smart cities have a significant role to play. It's common knowledge that air pollution in a city severely affects the health of its dependents. More alarmingly, human health damage and disease burden are caused by phenomena like acid rain, and global warming. More precisely, lung ailments, CPOD, heart problems and skin cancer are caused by polluted air in congested urban places. Amongst the worst air pollutants, CO, C6H6, SO2, NO2, O3, RSPM/PM10, and PM2.5 cause maximum havoc. The climatic variables like atmospheric wind velocity, direction, relative humidity, and temperature control air contaminants in the air. Lately, numerous techniques have been applied by researchers and environmentalists to determine the Air Quality Index over a place. However, not a single technique has found acceptance from all quarters as being effective in every situation or scenario. Here, the main aspect relates to achieving authentic prediction in AQI levels by applying Machine Learning algorithms so worst situations can be averted by timely action. To enhance the performance of Machine Learning methods study adopted imputation and feature selection methods. When feature selection is applied, the experimental outcomes indicate a more accurate prediction over other techniques, showing promise for the application of the model in smart cities by syncing data from different monitoring stations.

Methane sink of subterranean space in an integrated atmosphere-soil-cave system

CH4 serves as an important greenhouse gas, yet limited knowledge is available in global and regional CH4 cycling, particularly in widely distributed karst terrain. In this study, we investigated an upland in Puding Karst Ecosystem Research Station, and explored CH4 concentration and/or flux in atmosphere, soil and cave using a closed static chamber method and an eddy covariance system. Meanwhile, we monitored atmospheric temperature, precipitation, temperature and wind velocity in the cave entrance. The results demonstrated that atmospheric CH4 and actual soil CH4 fluxes in the source area of eddy covariance system were −0.19 ± 8.64 nmols−1m−2 and -0.16 nmols−1m−2 respectively. The CH4 concentrations in Shawan Cave exhibited 10 ∼ 100-fold lower than that of the external atmosphere. CH4 oxidation rate dominated by methane-oxidizing bacteria was 1.98 nmols−1m−2 in Shawan Cave when it combined with temperature difference between cave and external atmosphere. Therefore, CH4 sink in global karst subterranean spaces was estimated at 106.2 Tg CH4 yr−1. We supplemented an understanding of CH4 cycling paths and fluxes in karst terrain, as well as CH4 sinks in karst subterranean space. Further works require to establish a karst ecosystem observation network to conduct long-term integrated studies on CH4 fluxes regarding atmosphere, soils, plants and caves.

Accelerating flammable gas cloud dissipation in hydrogen leakage during refilling hydrogen-powered vehicles via employing canopy fans

Mitigating the hydrogen leakage risk during the refilling process contributes to promoting the hydrogen energy commercialization. In this study, the high-pressure hydrogen leakage and dilution characteristics were analyzed with fans installed on the hydrogen refueling station canopy. Two fan conditions are involved: blowing upwards condition, and blowing downwards condition. The role of leakage pressure, atmospheric wind velocity, and fan conditions on the spatiotemporal evolutionary characteristics of flammable gas clouds (FGC) were discussed. Results showed that the hydrogen distribution is significantly impacted by wind velocity and fan blowing conditions when the hydrogen-powered vehicle is refueled. At a small leakage pressure, under windless conditions, employing fans contribute to the FGC dissipation. At windy conditions the fan blowing upwards does not accelerate the FGC dissipation, but rather increases the its volume and slows down its dilution. At a large leakage pressure, at small wind velocities, fan blowing upwards contributes to FGC dilution. However, at large wind velocities, fan blowing upwards is not effective in accelerating the hydrogen dilution. In all the scenarios, fan blowing downwards always helps to accelerate the hydrogen dilution. This study offers a pragmatic approach to effectively mitigate the risk of hydrogen leakage during the refilling process.

A Cold Lid on a Warm Ocean: Indian Ocean Surface Rain Layers and Their Feedbacks to the Atmosphere

AbstractOcean surface rain layers (RLs) form when relatively colder, fresher, less dense rain water stably stratifies the upper ocean. RLs cool sea surface temperature (SST) by confining surface evaporative cooling to a thin near‐surface layer, and generate sharp SST gradients between the cool RL and the surrounding ocean. In this study, ocean‐atmosphere coupled simulations of the November 2011 Madden‐Julian Oscillation (MJO) event are conducted with and without RLs to evaluate two pathways for RLs to influence the atmosphere. The first, termed the “SST gradient effect,” arises from the hydrostatic adjustment of the boundary layer to RL‐enhanced SST gradients. The second, termed the “SST effect,” arises from RL‐induced SST reductions impeding the development of deep atmospheric convection. RLs are found to sharpen SST gradients throughout the MJO suppressed and suppressed‐to‐enhanced convection transition phases, but their effect on convection is only detected during the MJO suppressed phase when RL‐induced SST gradients enhance low‐level convergence/divergence and broaden the atmospheric vertical velocity probability distribution below 5 km. The SST effect is more evident than the SST gradient effect during the MJO transition phase, as RLs reduce domain average SST by 0.03 K and narrow vertical velocity distribution, thus delaying onset of deep convection. A delayed SST effect is also identified, wherein frequent RLs during the MJO transition phase isolate accumulated subsurface ocean heat from the atmosphere. The arrival of strong winds at the onset of the MJO active phase erodes RLs and releases subsurface ocean heat to the atmosphere, supporting the development of deep convection.

Direct Observation of Wave-Coherent Pressure Work in the Atmospheric Boundary Layer

Abstract Surface waves grow through a mechanism in which atmospheric pressure is offset in phase from the wavy surface. A pattern of low atmospheric pressure over upward wave orbital motions (leeward side) and high pressure over downward wave orbital motions (windward side) travels with the water wave, leading to a pumping of kinetic energy from the atmospheric boundary layer into the waves. This pressure pattern persists above the air–water interface, modifying the turbulent kinetic energy in the atmospheric wave-affected boundary layer. Here, we present field measurements of wave-coherent atmospheric pressure and velocity to elucidate the transfer of energy from the atmospheric turbulence budget into waves through wave-coherent atmospheric pressure work. Measurements show that the phase between wave-coherent pressure and velocity is shifted slightly above 90° when wind speed exceeds the wave phase speed, allowing for a downward energy flux via pressure work. Although previous studies have reported wave-coherent pressure, to the authors’ knowledge, these are the first reported field measurements of wave-coherent pressure work. Measured pressure work cospectra are consistent with an existing model for atmospheric pressure work. The implications for these measurements and their importance to the turbulent kinetic energy budget are discussed. Significance Statement Surface waves grow through a pattern of atmospheric pressure that travels with the water wave, acting as a pump against the water surface. The pressure pumping, sometimes called pressure work, or the piston pressure, results in a transfer of kinetic energy from the air to the water that makes waves grow larger. To conserve energy, it is thought that the pressure work on the surface must extract energy from the mean wind profile or wind turbulence that sets the shape of the wind speed with height. In this paper, we present direct measurements of pressure work in the atmosphere above surface waves. We show that the energy extracted by atmospheric pressure work fits existing models for how waves grow and a simple model for how waves reduce energy in the turbulent kinetic energy budget. To our knowledge, these are the first reported field measurements of wave-coherent pressure work.

Estimating the turbulent kinetic energy dissipation rate from one-dimensional velocity measurements in time

Abstract. The turbulent kinetic energy dissipation rate is one of the most important quantities characterizing turbulence. Experimental studies of a turbulent flow in terms of the energy dissipation rate often rely on one-dimensional measurements of the flow velocity fluctuations in time. In this work, we first use direct numerical simulation of stationary homogeneous isotropic turbulence at Taylor-scale Reynolds numbers 74≤Rλ≤321 to evaluate different methods for inferring the energy dissipation rate from one-dimensional velocity time records. We systematically investigate the influence of the finite turbulence intensity and the misalignment between the mean flow direction and the measurement probe, and we derive analytical expressions for the errors associated with these parameters. We further investigate how statistical averaging for different time windows affects the results as a function of Rλ. The results are then combined with Max Planck Variable Density Turbulence Tunnel hot-wire measurements at 147≤Rλ≤5864 to investigate flow conditions similar to those in the atmospheric boundary layer. Finally, practical guidelines for estimating the energy dissipation rate from one-dimensional atmospheric velocity records are given.

On the development of a generalized atmospheric boundary layer velocity profile for offshore engineering applications considering wind–wave interaction

Within industrial standards, effects due to wind–wave interaction on the marine atmospheric boundary layer (ABL) may be included via the Charnock sea-surface roughness parameter for open-sea and near-coastal waters. This roughness parameter does not accommodate the wide variety of wave states possible, nor does it modify the ABL to include speed-up effects resulting from an undulating wave profile. In an attempt to provide an updated definition of the general ABL profile for offshore wind engineering applications, an experimental and numerical study is performed to assess the interaction of the ABL on a fixed wave geometry. By extracting the mean velocity field during the wind–wave interaction, bespoke values of the velocity profile power exponent and wind risk factor can be obtained. A range of wave heights and wave lengths are considered from which a Kriging surrogate model is trained to supply the relevant wind profile parameters depending on the wave state. These newly garnered parameters enable the practitioner to define a reference wind velocity, and then adjust the velocity profile characteristics to contain the influence of the wave. This approach provides a new inlet velocity condition that can be used within computational wind engineering investigations without the need to explicitly model the wave surface, as well as flexibility in specifying the underlying wave conditions. Application of the re-calibrated velocity profile shows that wind forces are significantly greater throughout an offshore wind turbine (OWT) swept blade area when large (H= 15 m) and small (H= 1.5 m) wave heights are compared.

Computational study of the effect of building height on the performance of roof-mounted VAWT

The power of a Vertical Axis Wind Turbine (VAWT) placed at the frontal corner of a roof-top of a building is significantly higher compared to the same turbine in a uniform wind without a surrounding building. Due to the importance of this configuration's benefits, it is crucial to study its effect for different building heights. To investigate the impact of building height on the power performance of VAWTs, three buildings with heights of 30.48 m (100 ft), 60.96 m (200 ft), and 91.44 m (300 ft) are considered. A two-blade Darrieus-type VAWT is placed on the roof-top, with the wind flow directed straight towards the corner of the building. Computational Fluid Dynamics (CFD) is utilized to simulate the entire flow over the building and the rotating turbine. Different atmospheric boundary wind velocity profiles are considered. Firstly, the same velocity profile is applied to all three buildings, with taller buildings experiencing higher velocities. Secondly, three distinct velocity profiles are used over the buildings, ensuring that the wind velocity at the middle of the turbine for each case remains at 9.3 m/s. The results demonstrate that placing the VAWT on the roof-top of a 30.48 m (100 ft) building increases the maximum Power Coefficient (CP) by 36% compared to the turbine operating in a uniform flow. Moreover, in the case of one velocity profile applied to buildings with different heights, it was observed that the maximum CP increased by 84% for a building with a height of 91.44 m compared to the turbine operating in uniform flow. On the other hand, in the second scenario with three different velocity profiles over the buildings, it was found that the maximum CP increased by 18% and 22% when the turbine was placed in the 60.96 m and 91.44 m buildings, respectively, compared to the 30.48 m building.

Atmospheric highs drive asymmetric sea ice drift during lead opening from Point Barrow

Abstract. Throughout winter, the winds of migrating weather systems drive the recurrent opening of sea ice leads from Alaska's northernmost headland, Point Barrow. As leads extend offshore into the Beaufort and Chukchi seas, they produce sea ice velocity discontinuities that are challenging to represent in models. We investigate how synoptic wind patterns form leads originating from Point Barrow and influence patterns of sea ice drift across the Pacific Arctic. We identify 135 leads from satellite thermal infrared imagery between January–April 2000–2020 and generate an ensemble of lead-opening sequences by averaging atmospheric conditions and ice velocity across events. On average, leads open as migrating atmospheric highs drive differing ice–coast interactions across Point Barrow. Northerly winds compress the Beaufort ice pack against the coast over several days, slowing ice drift. As winds west of Point Barrow shift offshore, the ice cover fractures and a lead extends from the headland into the pack interior. Ice west of the lead accelerates as it separates from the coast, drifting twice as fast (relative to winds) as ice east of the lead, which remains coastally bound. Consequently, sea ice drift and its contribution to climatological ice circulation becomes zonally asymmetric across Point Barrow. These findings highlight how coastal boundaries modify the response of the consolidated ice pack to wind forcing in winter, producing spatially varying regimes of ice stress and kinematics. Observed connections between winds, ice drift, and lead opening provide test cases for sea ice models aiming to capture realistic ice transport during these recurrent deformation events.

The physics of desiccation cracks 1: Ductile fracturing and dependence on relative humidity

Ductile deformation is ubiquitously found in the shrinkage of geomaterials. The existence of ductility requires elastoplastic mechanics when analyzing the structure deformation under external stress. In this work, we explore the physics of ductile fracturing based on the results from desiccation experiments and triaxial tests. By using the digital image correlation (DIC) method to generate the strain maps of samples undergoing desiccation cracking under different relative humidities, we obtain results showing the previously postulated Cnoidal Wave ductile failure patterns propagating under atmospheric condition-controlled crack velocities. We then correlate these observations with rate-dependent plasticity models calibrated through triaxial tests undergoing several unloading–reloading cycles and velocity stepping. This work demonstrates the necessity to consider ductility in soil cracking, indicating that the formation of crack patterns in soil desiccation is a slow and predictable process.

Large eddy simulation of sneeze plumes and particles in a poorly ventilated outdoor air condition: A case study of the University of Houston main campus

Since the outbreak of the COVID-19 pandemic, many previous studies using computational fluid dynamics (CFD) have focused on the dynamics of air masses, which are believed to be the carriers of respiratory diseases, in enclosed indoor environments. Although outdoor air may seem to provide smaller exposure risks, it may not necessarily offer adequate ventilation that varies with different micro-climate settings. To comprehensively assess the fluid dynamics in outdoor environments and the efficiency of outdoor ventilation, we simulated the outdoor transmission of a sneeze plume in “hot spots” or areas in which the air is not quickly ventilated. We began by simulating the airflow over buildings at the University of Houston using an OpenFOAM computational fluid dynamics solver that utilized the 2019 seasonal atmospheric velocity profile from an on-site station. Next, we calculated the length of time an existing fluid is replaced by new fresh air in the domain by defining a new variable and selecting the hot spots. Finally, we conducted a large-eddy simulation of a sneeze in outdoor conditions and then simulated a sneeze plume and particles in a hot spot. The results show that fresh incoming air takes as long as 1000 s to ventilate the hot spot area in some specific regions on campus. We also found that even the slightest upward wind causes a sneeze plume to dissipate almost instantaneously at lower elevations. However, downward wind provides a stable condition for the plume, and forward wind can carry a plume even beyond six feet, the recommended social distance for preventing infection. Additionally, the simulation of sneeze droplets shows that the majority of the particles adhered to the ground or body immediately, and airborne particles can be transported more than six feet, even in a minimal amount of ambient air.

P62 SEASON VARIABILITY IN ATHEROSCLEROSIS COMPOSITION: INSIGHTS FROM 1848 NON–CULPRIT CORONARY PLAQUES

Abstract Background Several environmental and seasonal factors are thought to be crucial in the risk of acute coronary syndromes (ACS), including temperature, latitude, longitude, atmospheric air pressure, wind velocity and circadian period. However differences in coronary plaque composition according to season variation is still poorly understood. Purpose. Our study aims to analyse the characteristics of non–culprit coronary plaques in patients undergoing optical coherence tomography evaluation (OCT) evaluation of the left anterior descending artery. Methods We included 1848 non–culprit coronary plaques from 1003 patients of the CLIMA registry. The season of OCT pullback acquisition was collected for each patient. Results Overall, median age was 66 years (56–74), with 24.6% of women and 53.4% of ACS. At patient–level analysis, patients admitted in summer were less frequently affected by hypertension (59.8% vs 69.4% in autumn, 68.5% in winter and 72% in spring; p=0.027) and chronic kidney disease (14.8% vs 15.9% in autumn, 10.3% in winter and 19.4% in spring; p=0.037) in. At lesion–level analysis, similar values of fibrous cap thickness, maximum lipid arc, length of plaques and presence of macrophages were observed (Table 1). Summer plaques had a smaller minimum lumen area than spring plaques (5.7±3.1 vs 5.1±239; p=0.044) and also a less frequent superficial macrophage infiltration (23% vs 36.1% in autumn, 30.5% in winter and 30.6% in spring; p=0.030) and presence of cholesterol crystals (16.7% vs 23.8% in autumn, 28.4% in winter and 22.1% in spring; p=0.037 than three other season). Conclusions Coronary plaques during summer had less local sign of inflammation such superficial macrophage infiltration and cholesterol crystals. Further studies are needed to confirm these results and investigate clinical implications.

Современные представления о влиянии земной и космической погоды на здоровье человека (обзор)

It is known that terrestrial and space weather can have a significant impact on the functional state of the body, including in the form of meteoropathic reactions, acute illness or recurrence of chronic diseases. It seems necessary to analyse studies that have established cause-and-effect relationships between naturalclimatic factors and morbidity in order to determine the contribution of natural factors to public health risks and to identify priority indicators in order to improve social and hygienic monitoring. This article analyses scientific papers published in 2000–2021. Based on the search results in open data sources, 153 full-text publications were selected, of which 56 fully met the criteria for inclusion in a systematic review. We found that the most frequently studied natural and climatic factors were atmospheric temperature and humidity, atmospheric pressure, air velocity, solar activity, atmospheric electricity, and variations in the Earth’s magnetic field, including their frequency and combined effects. The objects of research were mainly patients with circulatory diseases: hypertension, ischaemic heart disease, cerebrovascular disease, and aortic aneurysms. However, according to the results of the studies, none of the factors can be clearly linked to the onset or development of the above diseases. This can be explained by the differences in the climatic conditions of the studies, by the cross-effect of meteorological and heliogeophysical factors, by sex and age differences of the studied groups, and by the influence of confounding factors such as diet, lifestyle, socioeconomic status, and bad habits. Thus, an integrated approach to the analysis of the accumulated data is required to improve our knowledge about the impact of terrestrial and space weather on humans. In order to effectively prevent and predict the development of weather-related health disorders, the key natural factors should be included into the system of social and hygienic monitoring.

Meteotsunamis and other anomalous “tidal surge” events in Western Europe in Summer 2022

We investigate occurrences of anomalous tidal activity in coastal waters of north-west Europe during Summer 2022. Sightings of an anomalous “tidal surge” occurred on 18 June 2022 in Wales, followed by similar observations in Ireland, France, and Spain. Several anomalous long-wave events were also reported in south England and Wales in the morning of 19 July 2022. We analyzed surface and high-altitude air pressure fields, and sea level oscillations for both days. Our detailed analysis reveals that the 18 June events were a series of meteotsunamis, propagating over several countries in Western Europe and triggered by localized pressure perturbations, originating within a low-pressure area over the North Atlantic Ocean. A local analysis of the southern coast of Ireland suggests that Proudman resonance was the determinant mechanism that amplified the meteotsunami traveling eastward in the afternoon of 18 June. A similar analysis of the 19 July events suggests that the tidal surge reported in the UK and anomalous signals recorded in Ireland and France were episodes of seiching triggered by infragravity waves, resonated subharmonically by wind waves. Numerical simulations of the 18 June event were performed with Volna-OP2, which solves the non-linear shallow water equations using a finite volume discretization. The influence of the atmospheric wave velocity on the amplification of the sea surface elevation is analyzed.

Prediction of coal seam gas content based on the correlation between gas basic parameters and coal quality indexes

The measurement of gas content in coal seam by means of indirect method involves heavy workload, long period, high cost and complicated operation and a proneness of negative values in the process of measuring gas absorption constant. To address these problems, the gas basic parameters and coal quality indexes of 90 coal samples from 90 coal mines in 13 provinces of China are determined experimentally in this paper. The intrinsic relationship between gas adsorption constant a and atmospheric adsorption capacity Q0-initial velocity index of gas emission Δp, gas adsorption constant b and volatile Vdaf - apparent density ARD is analyzed, and a prediction model of coal seam gas content based on gas basic parameters and coal quality index is established. The results show that the effect of Q0-Δp correlation on a is mainly caused by the change of specific surface area and gas pressure of coal, while the effect of Vdaf-ARD correlation on b is mainly caused by the change of pore volume of coal. By comparing the predicated value from the prediction model of coal seam gas content with the measured value, it is found that the average absolute error rate of predicted value is 8.15%. This method is proven to be effective and feasible in routine gas content predictions, and can provide a reference for coal seam gas content prediction in China.