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Tropospheric ozone concentrations have trended downward in many U.S. cities since 2000. In Texas, however, concentrations and regulatory exceedances abruptly rose in Dallas-Fort Worth after 2020. To explore this anomaly, the following metrics were compiled for each day from January 1, 2001--December 31, 2023: maximum daily 8-hr average (MDA8) ozone concentrations, number of days with MDA8 ozone concentrations exceeding 0.070 ppm, average nitrogen oxides (NOx, ppb), and meteorological variables. Measurements were taken at a monitoring station in northern Dallas-Fort Worth. Levels of MDA8 ozone most strongly correlated with noon solar radiation (positive), followed by maximum temperature (positive), noon relative humidity (negative), noon wind speed (negative), and average NOx (positive). After a long-term decline from 2000 to 2020, MDA8 ozone concentrations and regulatory exceedances sharply increased, a trend associated with increased solar radiation and air temperatures in the study area. Results suggest that warmer atmospheric conditions associated with global warming are also increasing ground-level ozone concentrations in the study area. [ABSTRACT FROM AUTHOR]

This study aimed to identify the meteorological factors that contribute to dengue epidemics. The monthly incidence of dengue was used as the outcome variable, while maximum temperature, humidity, precipitation, and sunshine hours were used as independent variables. The results showed a consistent increase in monthly dengue cases from 2013 to 2021, with seasonal patterns observed in stationary time-series data. The ARIMA (2, 1, 3) × seasonal (0, 1, 2)12 model was used based on its lowest Akaike Information Criterion (AIC) values. The analysis revealed that a 1-unit increase in rainfall was positively correlated with a small 0.062-unit increase in dengue cases, whereas a 1-unit increase in humidity was negatively associated, leading to a substantial reduction of approximately 16.34 cases. This study highlights the importance of incorporating weather data into national dengue prevention programs to enhance public awareness and to promote recommended safety measures. [ABSTRACT FROM AUTHOR]

The Hadley circulation (HC) has been expanding poleward in recent decades. The Coupled Model Intercomparison Project Phase 6 (CMIP6) models predict that the expansion will accelerate in the future, more so in the Southern Hemisphere (SH). However, the extent of the expansion varies widely among the models. We investigate the mechanisms driving the intermodel spread in SH HC expansion predictions. The intermodel spread is obtained by an empirical orthogonal function analysis on the SH HC trend patterns of 16 CMIP6 model simulations using the historical and shared socioeconomic pathway 5–8.5 scenarios. The leading mode, showing a mean meridional stream function anomaly at the poleward SH HC extent, explains 49.73% of the variance and significantly correlates (r = 0.94) with the SH HC expansion. By analyzing the extended Kuo‐Eliassen equation, we find that the intermodel difference in the representation of diabatic heating is responsible for about 14% of the intermodel spread. The meridional eddy momentum and heat fluxes contribute to about 21% and 18% of the intermodel spread, respectively. The models simulating a relatively large SH HC expansion tend to show increased precipitation in the Southern Pacific Convergence Zone, reduced baroclinic instability in the subtropics, and an enhanced poleward shift of jet stream in the midlatitudes. This suggests that the uncertainty in the HC projection may be constrained by reducing the bias in the trend of the mean fields. Plain Language Summary: The Hadley circulation (HC), which affects global climate patterns, is expanding toward the poles. However, different climate models predict varying extents of this expansion, especially in the Southern Hemisphere (SH). We aim to understand why. By analyzing climate model data, we identified key factors influencing the spread in SH HC expansion. Our findings suggest that factors like diabatic heating and meridional eddy momentum play significant roles. Models showing greater SH HC expansion tend to simulate increased precipitation in specific regions and shifts in atmospheric jet streams. Addressing these model biases could help reduce uncertainty in future HC projections. Key Points: The first intermodel stream function trend mode effectively captures the spread of the Southern Hemisphere Hadley Circulation expansionThe intermodel spread in expansion is explained by the spread of the meridional eddy momentum, heat fluxes, and diabatic heatingThe spread of the eddy fluxes and diabatic heating are linked with the changes in precipitation, jet, and static stability [ABSTRACT FROM AUTHOR]

We explore ocean circulation on a rotating icy moon driven by temperature gradients imposed at its upper surface due to the suppression of the freezing point of water with pressure, as might be induced by ice thickness variations on Enceladus. Using high-resolution simulations, we find that eddies dominate the circulation and arise from baroclinic instability, analogous to Earth's weather systems. Multiple alternating jets, resembling those of Jupiter's atmosphere, are sustained by these baroclinic eddies. We establish a theoretical model of the stratification and circulation and present scaling laws for the magnitude of the meridional heat transport. These are tested against numerical simulations. Through identification of key nondimensional numbers, our simplified model is applied to other icy moons. We conclude that baroclinic instability is central to the general circulation of icy moons. [ABSTRACT FROM AUTHOR]

The allergic airway disease, such as allergic rhinitis, chronic rhinosinusitis, asthma, is a general term of a range of inflammatory disorders affecting the upper and lower airways and lung parenchyma. This study aimed to investigate the short-term effects of air pollutants and meteorological factors on AAD-related daily outpatient visits. An ecological study. Data on outpatient visits due to AAD (n = 4,554,404) were collected from the platform of the Ningbo Health Information from January 1, 2015 to December 31, 2021. A Quasi-Poisson generalized additive regression model was established to analyze the lag effects of air pollution on daily outpatient visits for AAD. Restricted cubic spline functions were used to explore the potential non-linear relationships between air pollutants and meteorological and daily outpatient visits for AAD. PM 2.5 , PM 10 , SO 2 , NO 2 , or CO were associated with daily outpatient visits for AAD, and there was a significant increasing trend in the cumulative lag effects. SO 2 had the largest effect at Lag07, with a 25.3% (95% CI: 21.6%–29.0%) increase in AAD for every 10 μg/m3 increase in exposure concentration. Subgroup analysis showed that the 0–18 years old age group had the strongest effects, especially for AR, and all effects were stronger in the cold season. Given that patients aged 0–18 are more susceptible to environmental changes, protective measures specifically for children should be taken during dry and cold weather conditions with poor air quality. [Display omitted] [ABSTRACT FROM AUTHOR]

A wave–current coupled numerical model with 3D radiation stress formalism is used to study baroclinic effects, specifically stratification and baroclinic pressure gradient force (BcPGF), on wind-wave-driven flows, separated as vertically sheared flows and vertically homogeneous flows. Numerical experiments are conducted under ideal offshore winds of 8 m s−1. Results show that stratification enhances the two-layer structure of the wave-driven sheared flow, while BcPGF has minimal impact. Stratification and BcPGF have limited influence on the direction of the wave-driven depth-averaged circulation, but they can enhance the total circulation by promoting the upper one. In the upper layer where form drag dominates, the competition between the vertical form drag divergence (FDD) and turbulent stress divergence (TSD) plays a critical role in shaping the wave-driven flow. Stratification reduces vertical eddy viscosity Km, suppressing the growth of TSD associated with the vertical shear of velocity, which facilitates the FDD driving the upper outflow. Likewise, stratification can enhance the effect of FDD curl on the upper horizontal circulation by limiting the growth of TSD curl related to the vertical shear of vorticity. Additionally, low Km reinforces geostrophic effect and therefore enhances the lateral circulation. Baroclinic torque contributes to reducing the vertical variation of vorticity and the growth of TSD curl, indirectly improving the effectiveness of FDD curl in driving the upper circulation. Stratification undergoes fortnightly adjustments due to the spring–neap cycle, leading to the synchronized variation in the strength of wave-driven flow, particularly its vertically sheared component. During neap tides with weak tidal forcing and well-developed stratification, wave-driven sheared flow, horizontal circulation, and lateral circulation are stronger. Significance Statement: The aim of this study is to enhance our comprehension of the impact of baroclinic processes on wind-wave-driven flows in wind-dominated regimes. During summer, wave-driven flows exhibit noticeable vertical shearing, which differ from those observed in winter. This is particularly important because during summer, river runoffs generate strong stratification and introduce large quantities of terrigenous materials into coastal oceans. Consequently, wave-driven flows may play a crucial role in bay-shelf exchange, which has been given in few studies. Our findings highlight the influence of baroclinic processes on turbulent stress divergence, which can enhance wave-driven flows, both the vertically sheared and the vertically homogeneous components, especially during neap tides. [ABSTRACT FROM AUTHOR]

We collected meteorological and urolithiasis-related hospitalization data from four counties in Ganzhou City for 2018–2019 and used the DLNM method to assess the lagged and cumulative effects of temperature on urolithiasis hospitalizations and obtain the total effect after meta-combination. Based on the nonlinear association between temperature and urolithiasis hospitalizations, the relative risk of overall high temperature (30℃) was 2.10 (95% CI: 1.07-4.10). No statistically significant difference (p = 0.07) was observed between males (RR = 2.04, 95% CI: 1.42-2.94) and females (RR = 1.45, 95% CI: 1.09-1.92) for the heat effect, which was higher in the ≥ 60 years age group (RR = 3.18, 95% CI: 1.76-5.76) than in the < 60 years age group (p = 0.007). High temperatures increased the risk of hospitalization for urolithiasis in Ganzhou, China, and the risk was greatest for individuals aged 60 and above, with similar risks observed across counties and genders. [ABSTRACT FROM AUTHOR]

This study focuses on El Niño impacts on springtime extreme precipitation in Southeastern China (SEC) by comparing observations with data from the Coupled Model Intercomparison Project phase 6 (CMIP6) historical runs. Observational and simulated results suggest that synoptic-scale temperature advection patterns over East Asia (EA) are closely associated with extreme precipitation in SEC, encompassing the Pearl River Basin (PRB), Yangtze River Basin (YRB), and Huaihe River Basin (HRB). Based on this, we introduce a temperature advection index (TAI) tailored to capture the cold-warm temperature advection dipole, which shows a significant positive correlation with SEC precipitation. Both observations and CMIP6 indicate that TAI-related circulations, characterized by upper-level synoptic-scale waves and a north–south oriented temperature gradient over EA, are conducive to extreme precipitation in northern PRB (NPRB)–YRB–HRB. However, the TAI-related synoptic-scale activities have a lesser impact on extreme precipitation in southern PRB (SPRB), as these disturbances mainly affect the mid-latitude weather. Further investigation reveals that during boreal spring following El Niño, 85% of extreme events in YRB–HRB are associated with positive TAI values, compared to 76% under climatological conditions. However, such a change in the association with TAI is not evident in CMIP6 simulations. From observations, atmospheric baroclinicity along the East Asian westerly jet is enhanced during El Niño, which promotes the development of TAI-related synoptic-scale disturbances. In contrast, CMIP6 models struggle to reproduce these observed baroclinicity signals during El Niño. This challenge arises from the background westerly jet bias and mean-state cold tongue bias in tropical Pacific temperature in models. [ABSTRACT FROM AUTHOR]

Background/Objectives: The external environment constantly influences human health through many factors, including air quality, access to green spaces, exposure to pollutants, and climate change. Contamination poses a substantial threat to human well-being; conversely, environmental factors also positively impact health. The purpose of this study is to provide a comprehensive review of the complex relationship between various environmental factors and human health. While individual studies have explored specific aspects, a broader integrative understanding is lacking. Methods: Through databases (PubMed, Cochrane, Copernicus), 4888 papers were identified, with 166 selected for detailed analysis. Results: We summarized recent research, identifying multiple associations between environmental factors such as air pollution, climate change, solar radiation, and meteorological conditions and their impact on various health outcomes, including respiratory, cardiovascular, metabolic and gastrointestinal, renal and urogenital, neurological and psychological health, infectious and skin diseases, and major cancers. We use chord diagrams to illustrate these links. We also show the interaction between different environmental factors. Findings begin with exploring the direct impact of environmental factors on human health; then, the interplay and combined effects of environmental factors, elucidating their (often indirect) interaction and collective contribution to human health; and finally, the implications of climate change on human health. Conclusions: Researchers and policymakers need to consider that individuals are exposed to multiple pollutants simultaneously, the "multipollutant exposure phenomenon". It is important to study and regulate environmental factors by considering the combined impact of various pollutants rather than looking at each pollutant separately. We emphasize actionable recommendations and solutions. [ABSTRACT FROM AUTHOR]

The study examines the wake dynamics of a heated square cylinder in the presence of thermal buoyancy through numerical simulations. It reveals a transition from chaotic to periodic or quasiperiodic patterns as heating levels increase, with the onset of three-dimensionality triggered at a critical Reynolds number of 173. The research also delves into the influence of baroclinic vorticity production on wake dynamics and the variation of wake behavior with increasing heating levels. The document compiles research articles on fluid dynamics, heat transfer, and flow transitions related to square cylinders and other geometries, contributing to the understanding of complex fluid dynamics phenomena. [Extracted from the article]

Objectives. This study is to analyze the epidemiological characteristics of other infectious diarrhea diseases (OIDDs) reported in Guangzhou in the past 15 years and the meteorological data of the city in the same period, to explore the correlation between meteorological factors and the incidence. Methodology. This study starts with using quartiles to test the normal distribution of case data. This study has selected five meteorological factors with the highest correlation coefficients and case data from 2006 to 2018 were used to establish a multiple linear regression equation, and the regression equation was tested with case data from 2019 to 2020. Results. Regression modeling based on the statistics for OIDDs during 2006 to 2018 obtained a correlation coefficient R (multiple R) value of about 0.50. The R square value, also known as the coefficient of determination or goodness of fit, was about 0.25. The adjusted R square value was about 0.25. The overall significance test value (significance F) in the regression equation was much lower than the F statistic, thereby indicating that the dependent variable and independent variable were significant. Conclusion. The results indicated that factors other than meteorological or social factors should be considered to understand the outbreak of OIDDs in Guangzhou. [ABSTRACT FROM AUTHOR]

The information entropy budget and the rate of information transfer between variables is studied in the context of a nonlinear reduced‐order atmospheric model. The key ingredients of the dynamics are present in this model; namely, the baroclinic instability, the instability related to the presence of an orography, the dissipation related to the surface friction, and the large‐scale meridional imbalance of energy. For the parameters chosen, the solutions of this system display a chaotic dynamics reminiscent of the large‐scale atmospheric dynamics in the extratropics. The detailed information entropy budget analysis of this system reveals that the linear rotation terms play a minor role in the generation of uncertainties compared with the orography and the surface friction. Additionally, the dominant contribution comes from the nonlinear advection terms, and their decomposition in synergetic (covariability) and single (impact of each single variable on the target one) components reveals that for some variables the covariability dominates the information transfer. The estimation of the rate of information transfer based on time series is also discussed, and an extension of the Liang's approach to nonlinear observables is proposed. [ABSTRACT FROM AUTHOR]

In this study, the medium‐range predictability of heatwave (HW) onsets in four midlatitude European regions is investigated statistically with the help of ensemble reforecasts for the period 2001–2018. The concept of Euro‐Atlantic weather regimes is adopted to characterise HWs (about 50 in each region) and to study whether forecast skill may depend on the large‐scale dynamical setup. HW onsets over the British Isles and Scandinavia are mainly associated with Scandinavian and European blocking regimes, whereas the "no regime" case is observed more frequently for Central Europe. Stratified by weather regime, the predictability of heatwave onsets is then studied by means of a multiple metric‐based analysis of European Centre for Medium‐Range Weather Forecasts (ECMWF) and Global Ensemble Forecast System Version 12 (GEFSv12) ensemble reforecasts. For two of the regions considered, Central Europe and the British Isles, a conclusive picture is obtained: medium‐range predictive skill is significantly higher for HW onsets associated with Scandinavian or European blocking compared with cases with no pronounced regime. This skill advantage mostly concerns the large‐scale flow and, to some extent, 850‐hPa temperatures, but is generally not reflected in the correct prediction of near‐surface temperatures. Finally, we investigate for two regions how exceptionally good or poor forecasts are related to the atmospheric state during or shortly after forecast initialisation. At 10 days lead time, poor large‐scale flow predictive skill for Central European HW onsets is linked to anomalously high baroclinicity further upstream and an intensified North Atlantic jet stream, whereas good forecasts on average feature an initial state close to climatology. Forecast skill for near‐surface temperatures is not affected by such dynamical precursors, but rather by pre‐existing soil‐moisture anomalies. For the British region, exceptionally good forecasts of both large‐scale flow and near‐surface temperatures are associated with an already established continental blocking. In contrast to Central Europe, pre‐existing soil‐moisture anomalies play less of a role there. [ABSTRACT FROM AUTHOR]

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Latent heating modifies the jet stream by modifying the vertical geostrophic wind shear, thereby altering the potential for baroclinic development. Hence, correctly representing diabatic effects is important for modelling the mid-latitude atmospheric circulation and variability. However, the direct effects of diabatic heating remain poorly understood. For example, there is no consensus on the effect of latent heating on the cross-jet temperature contrast. We show that this disagreement is attributable to the choice of spatio-temporal averaging. Jet representations relying on averaged wind tend to have the strongest latent heating on the cold flank of the jet, thus weakening the cross-jet temperature contrast. In contrast, jet representations reflecting the two-dimensional instantaneous wind field have the strongest latent heating on the warm flank of the jet. Furthermore, we show that latent heating primarily occurs on the warm flank of poleward directed instantaneous jets, which is the case for all storm tracks and seasons. [ABSTRACT FROM AUTHOR]

Three dominant characteristics and underlying dynamics of the seasonal cycle in Baffin Bay are discussed. The study is based on a regional, high‐resolution coupled sea ice‐ocean numerical model that complements our understanding drawn from observations. Subject to forcing from the atmosphere, sea ice, Greenland, and other ocean basins, the ocean circulation exhibits complex seasonal variations that influence Arctic freshwater storage and export. The basin‐scale barotropic circulation is generally stronger (weaker) in summer (winter). The interior recirculation (∼2 Sv) is primarily driven by oscillating along‐topography surface stress. The volume transport along the Baffin Island coast is also influenced by Arctic inflows (∼0.6 Sv) via Smith Sound and Lancaster Sound with maximum (minimum) in June‐August (October‐December). In addition to the barotropic variation, the Baffin Island Current also has changing vertical structure with the upper‐ocean baroclinicity weakened in winter‐spring. It is due to a cross‐shelf circulation associated with spatially variable ice‐ocean stresses that flattens isopycnals. Greenland runoff and sea ice processes dominate buoyancy forcing to Baffin Bay. Opposite to the runoff that freshens the west Greenland shelf, stronger salinification by ice formation compared to freshening by ice melt enables a net densification in the interior of Baffin Bay. Net sea ice formation in the past 30 years contributes to ∼25% of sea ice export via Davis Strait. The seasonal variability in baroclinicity and water mass transformation changes in recent decades based on the simulation. Plain Language Summary: Baffin Bay ocean circulation is important for Arctic freshwater exports that may influence subpolar deep convection. However, we have little knowledge about how it works in winter due to limited observations. This study investigates three dominant aspects of the seasonal cycle in Baffin Bay ocean circulation and hydrography with a high‐resolution ice‐ocean coupled model. The basin‐scale barotropic circulation (depth‐integrated transport) is stronger in summer and weaker in winter, mainly driven by along‐topography surface stress and Arctic inflows. The baroclinicity (vertical velocity shear) of the Baffin Island Current is weakened in winter associated with spatially uneven ice‐ocean stresses. Net sea ice formation in Baffin Bay in the past 30 years makes Baffin Bay water densified and increases the sea ice export through Davis Strait. Changes of seasonality in Baffin Bay in the past 30 years are also discussed using model results. Key Points: Basin‐scale barotropic circulation varies seasonally and is mainly forced by along‐topography surface stressBaffin Island Current is less surface intensified in ice seasons due to ice‐ocean stress curl induced cross‐shelf circulationNet sea ice formation makes Baffin Bay water densified and increases the sea ice export through Davis Strait [ABSTRACT FROM AUTHOR]

Energetic mesoscale eddies are often accompanied by strong submesoscale variability, which plays a significant role in connecting mesoscale and turbulent motions in the ocean and leads to strong vertical motions. The product of a high‐resolution (1/48°) oceanic numerical model, the LLC4320, is employed to investigate the seasonal variations of vertical heat transport induced by submesoscale processes within multiple mesoscale eddies in the Kuroshio Extension (KE) region. In different seasons, the submesoscale vertical heat transport exhibits a consistent upward pattern, with notably higher magnitudes observed during winter. In winter, the maxima value of submesoscale vertical heat flux (SVHF) can account for approximately 60% of the total vertical heat flux (VHF). This is equivalent to the average net sea surface heat flux in a single eddy region. In summer and autumn, the maxima absolute value of submesoscale vertical heat flux can account for approximately 30% of the total VHF. Energy analysis reveals that baroclinic instability associated with vertical buoyancy flux has a crucial effect on generating submesoscale processes within the eddy region. The submesoscale motions are influenced by the mixed layer instability, strain‐induced frontogenesis, turbulent thermal wind and turbulent thermal wind‐induced frontogenesis within the upper mixed layer, while they are largely associated with the strain‐induced frontogenesis in the ocean interior. Furthermore, the upward low‐frequency submesoscale vertical heat transport is generated by submesoscale secondary circulation at eddy peripheries. Plain Language Summary: A high‐resolution ocean model is used to investigate how submesoscale processes affect vertical heat transport in ocean eddies. Regardless of the season, heat is consistently transported upwards by these submesoscale motions with the strongest effect observed in winter and accounting for nearly 60% of the total heat transport in this way. The analysis shows that the instability caused by differences in buoyancy plays a key role in generating the submesoscale processes within the eddy regions. These processes are influenced by the mixed layer instability, frontogenesis, and turbulent thermal wind processes in the upper layer, whereas only the strain‐induced frontogenesis affects these processes in the ocean interior. Additionally, the upward submesoscale vertical heat transport is facilitated by submesoscale secondary circulation occurring at eddy edges. Key Points: Submesoscale vertical heat transports in eddy regions are upward throughout all seasons and have higher magnitudes in winterStrain‐induced frontogenesis generates submesoscale processes within eddy regions in the ocean interiorSubmesoscale secondary circulation at eddy peripheries induces upward low‐frequency submesoscale vertical heat transport [ABSTRACT FROM AUTHOR]

Prior research extensively investigates the delayed influence of El Niño‐Southern Oscillation (ENSO) events on subsequent summer climates, with persistent sea surface temperature anomalies (SSTAs) in remote tropical oceans serving as crucial pathways. This study unveils a previously overlooked midlatitude pathway. During the developing winter, El Niño events induce basin‐scale cold SSTAs in the central North Pacific, which can persist into the following summer. These anomalies significantly influence early‐summer atmospheric circulation by enhancing atmospheric baroclinicity and transient eddy activities. Primarily driven by transient eddy vorticity forcing, an equivalent barotropic geopotential low anomaly emerges over the North Pacific. Enhanced by the southwesterly winds of the atmospheric low, tropical moisture is transported farther northeastward in the early summer, resulting in increased rainfall in the Pacific Northwest region. By elucidating this meridional pathway, our study advances the understanding of ENSO's delayed impacts and associated dynamical processes, in which the midlatitude oceanic feedbacks are emphasized. Plain Language Summary: The El Niño‐Southern Oscillation (ENSO) events are considered as a primary driver of climate anomalies. Even during their decaying phase, its impact on the Northern Hemisphere summer climate remains notable. This study delves into the intricate mechanisms underlying the delayed impacts of ENSO events on subsequent summer climates. While prior research has extensively explored the zonal pathways involving tropical Indian and Atlantic oceans, this study illuminates a previously overlooked meridional pathway. It reveals that El Niño events trigger significant cold sea surface temperature anomalies (SSTAs) in the North Pacific during their mature phase in winter, which persist into the following summer. These SSTAs wield substantial influence over early‐summer atmospheric circulation, fostering atmospheric baroclinicity and transient eddy activities. Consequently, an anomalous low‐pressure system emerges over the North Pacific in early summer, enhancing southwesterly winds and transporting tropical moisture farther northeastward. This moisture influx results in increased rainfall in the Pacific Northwest region. By elucidating this meridional pathway, the study advances our comprehension of ENSO's delayed impacts, highlighting the crucial role of midlatitude oceanic feedbacks. In essence, it demonstrates how ENSO events can influence North American climate anomalies during subsequent early summer, shedding light on a previously unrecognized pathway of ENSO's effect. Key Points: Cold central North Pacific sea surface temperature anomalies (SSTAs), initiated by El Niño events, can endure into the subsequent summerBy transient eddy forcing, these cold SSTAs induce a whole‐layer geopotential low anomaly over North Pacific in post‐El Niño early summerThus, northeastward moisture transport strengthens, boosting increased early‐summer rainfall in Pacific Northwest after El Niño events [ABSTRACT FROM AUTHOR]

The mid‐latitude extreme weather disasters are often associated with explosively developing cyclones (ECs). Based on different vertical development characteristics, 4,608 ECs identified over the North Pacific in the cold season of 44 years of NCEP‐CFSR reanalyzes are divided into four types of upward development and four types of downward development categories. ECs with vertical upward (downward) development follow a northeastward (nearly eastward) path, mainly explosively developing over the Northwest Pacific (Asia continent and Pacific). Furthermore, utilizing the piecewise potential vorticity inversion method reveals the synergetic forcing of the turbulent heat transport and baroclinicity in the lower troposphere, the latent heat release in the middle levels, the upper‐level jet stream, and the downward intrusion of stratospheric potential vorticity on the ECs. Different configurations of these influences from the troposphere to the stratosphere result in the occurrences of eight types of ECs in the cold season over the North Pacific. Plain Language Summary: Since the late twentieth century, there has been a significant variation in the frequency of explosively developing cyclones (ECs), which bring extreme weather disasters to the mid‐latitudes. This study classifies winter North Pacific ECs into four upward and four downward developing categories. The upward developing ECs include those enhanced only in the lower troposphere (UL‐EC), those developing upward to the middle troposphere (UM‐EC), those developing upward to the upper troposphere (UU‐EC), and those developing upward into the stratosphere (US‐EC). In contrast, the downward developing ECs can be classified as those intensifying only in the upper troposphere (DU‐EC), those developing downward to the middle troposphere (DM‐EC), those developing downward to the lower troposphere (DL‐EC), and those developing downward from the stratosphere (DS‐EC) to the lower troposphere. Furthermore, the piecewise potential vorticity inversion results show that the explosive development of UL‐EC and UM‐EC are dominated by the thermodynamical processes in the middle‐to‐lower troposphere, exhibiting a baroclinic structure with opposite anomalous geopotential height between the troposphere and stratosphere. However, the other types have a consistent stratospheric‐to‐tropospheric negative anomalies, which is determined by the upper‐layer dynamical processes. The downward intrusion of stratospheric potential vorticity dominates the explosive development for the US‐EC and DS‐EC. Key Points: The North Pacific explosively developing cyclones during cold season are divided into eight up‐ and down‐ward vertically developing typesThe explosively developing cyclones are proved to be an important link between the stratosphere and troposphere in the mid‐high latitudesUsing the piecewise potential vorticity inversion method, the quantitative forcings on the explosively developing cyclones are explored [ABSTRACT FROM AUTHOR]

Starting from the classical quasi-geostrophic potential vorticity equation with equal depth two-layer fluid, the coupled cylindrical Kadomtsev–Petviashvili (KP) equations with variable coefficients for Rossby waves are studied. To be more general, the phase velocity is considered an indefinite integral about time and improves the analysis procedure. So the variable coefficients are obtained and some previous studies are reasonably explained. The cylindrical wave theory is therewith utilized to reduce the coupled cylindrical KP equations with variable coefficients, and based on the modified Hirota bilinear method, the lump solutions and interaction solutions are found. Through numerical simulations, the Rossby lump waves on both sides of the y axis move closer to the center, and their amplitude gradually decreases and tends to flatten with the generalized Rossby parameter growth. In the Rossby waves flow field, the dipole structures propagate to the east and lead to the appearance of the compress phenomenon during barotropic–baroclinic interaction. It is possibly useful for further theoretical research on atmospheric phenomena. [ABSTRACT FROM AUTHOR]

Existing evidence suggested that the risk of tuberculosis (TB) infection was associated to the variations in temperature and PM2.5. A total of 9,111 cases of TB were reported in Ningxia Hui Autonomous Region, China from 2013 to 2015 on a daily basis, and 57.2% of them were male. The TB risk was more prominent for a lower temperature in males (RR of 1.724, 95% CI: 1.241, 2.394), the aged over 64 years (RR of 2.241, 95% CI: 1.554, 3.231), and the high mobility occupation subpopulation (RR of 2.758, 95% CI: 1.745, 4.359). High concentration of PM2.5 showed a short-term effect and was only associated with an increased risk in the early stages of exposure for the female, and aged 36–64 years group. There were 15.06% (1370 cases) of cases of TB may be attributable to the temperature, and 2.94% (268 cases) may be attributable to the increase of PM2.5 exposures. Low temperatures may be associated with significantly increase in the risk of TB, and high PM2.5 concentrations have a short-term association on increasing the risk of TB. Strengthening the monitoring and regular prevention and control of high risk groups will provide scientific guidance to reduce the incidence of TB. [ABSTRACT FROM AUTHOR]

Polar lows (PLs) are intense mesoscale cyclones that form over polar oceans during colder months. Characterized by high wind speeds and heavy precipitation, they profoundly impact coastal communities, shipping, and offshore activities. Amid the substantial environmental changes in polar regions due to global warming, PLs are expected to undergo noteworthy transformations. In this study, we investigate the response of PL development in the Barents Sea to climate warming based on two representative PLs. Sensitivity experiments were conducted including the PLs in the present climate and the PLs in a pseudo–global warming scenario projected by the late twenty-first century for Shared Socioeconomic Pathway (SSP) 2-4.5 and SSP 3-7.0 scenarios from phase 6 of the Coupled Model Intercomparison Project (CMIP6). In both warming climate scenarios, there is an anticipated decrease in PL intensity, in terms of the maximum surface wind speed and minimum sea level pressure. Despite the foreseen increase in latent heat release in the future climate, contributing to the enhancement of PL intensity, other primary factors such as decreased baroclinic instability, heightened atmospheric static stability, and reduced overall surface heat fluxes play pivotal roles in the overall decrease in PL intensity in the Barents Sea under warming conditions. The augmentation of surface latent heat flux, however, results in increased precipitation associated with PLs by enhancing the latent heat release. Furthermore, the regional steering flow shifts in the warming climate can influence the trajectory of PLs during their development. Significance Statement: Global warming is anticipated to impact cyclone systems worldwide. Polar lows (PLs), intense mesocyclones in polar regions with potential socioeconomic and human life implications, pose uncertainties regarding intensity changes in a warming climate. In this study, we aimed to better understand how PLs over the Barents Sea will respond to the environmental changes in future climate conditions [Shared Socioeconomic Pathway (SSP) 2-4.5 and SSP 3-7.0] by the end of the twenty-first century. Our results find that the intensity of PLs is expected to decrease in the future while there is an expected increase in precipitation associated with PLs in the warming climate. These findings aim to contribute valuable insights for disaster management strategies in the face of evolving climate scenarios. [ABSTRACT FROM AUTHOR]

Background: There is scarcity of data exploring the dynamics of barriers to changing physical activity (PA) and eating habits during a lifestyle intervention in a primary care setting. The aim of the present study was to investigate barriers to lifestyle change before and during a primary care lifestyle intervention in adults with different sociodemographic backgrounds. Methods: Barriers to healthy eating and PA were assessed in 114 adults (age = 55 ± 9 years) using a questionnaire before inclusion in the intervention. During the lifestyle intervention, factors perceived as obstacles to reach goals for PA and healthy eating habits were collected using focus group interviews in a sub-sample of 25 adults and analyzed using thematic analysis. Results: At least 1 barrier to changing eating and PA habits was reported in 65% and 67% of the population, respectively, without differences due to sex, place of birth, and educational level. Before entering the lifestyle intervention, intrapersonal factors including lack of willpower and lack of enjoyment were the dominant barriers to PA and healthy eating, irrespective of place of birth, sex, and education level. In contrast, environmental factors such as lack of support from family and work-related constraints emerged as important barriers to overcome during the action phase of the lifestyle intervention. Conclusions: The present study highlights the dynamics of barriers to changing PA and eating habits in a primary care lifestyle intervention, emphasizing the need for barrier assessment during the different phases of an intervention to tailor support activities for successful lifestyle behavioral change. [ABSTRACT FROM AUTHOR]

Deep atmospheric convection is often observed over the Kuroshio in the East China Sea (ECSK). However, the mechanisms by which warm oceanic currents fuel transient deep convection are not fully understood. This study investigates an atmospheric cold front that brought heavy precipitation as it traversed the ECSK in April 2004. The southwesterlies ahead of the cold front advected moist and warm air, creating a zone with high convective available potential energy (CAPE) values. As the cold front approached the ECSK, the pre‐frontal high CAPE values coalesced with those over the warm current that substantially strengthened the deep convection, with precipitation rate increasing from 3 mm hr−1 to 10 mm hr−1. A numerical model well simulated the marked increase in precipitation over the ECSK, permitting the isolation of the ECSK's influence by contrasting the control (CTRL) run with an experiment with smoothed sea surface temperatures (SMTH run). Results show the ECSK contributed to 46% of the precipitation over the warm current. The ECSK was found to amplify ascending motion and elevate neutral buoyancy levels, extending its effect up to the tropopause. Furthermore, the strengthened deep convection significantly lowered the sea level pressure (SLP) over the ECSK and impressed upon the time‐mean SLP field. An additional experiment with lowered SST underscored the high SST's critical role in deep convection. This case study suggests a novel pathway by which the effects of warm oceanic currents influence the upper troposphere under extreme conditions with strong baroclinic instability. Plain Language Summary: Warm ocean currents like the Kuroshio in the East China Sea can shape the weather above, often causing towering clouds and heavy rainfalls. Understanding how this happens is key to better weather forecasts. Our research focused on an event in April 2004, when a cold front passing over the Kuroshio led to intense rain. We used satellite data and computer simulations to see how the warm current influenced the storm. We found that the Kuroshio, by warming and adding moisture to the surface air, strengthened the storm and increased its height, resulting in more rainfall. This effect also left a noticeable imprint on the sea‐level pressure field. These results are important because they help us understand and better predict the impact of warm ocean currents on severe weather events. Key Points: An atmospheric cold front swept over the East China Sea Kuroshio (ECSK) and produced heavy precipitation over the warm currentThe ECSK increased surface moist entropy, which intensified the precipitation from deep convectionThe cold‐frontal deep convection projected the ECSK's effect up to the tropopause [ABSTRACT FROM AUTHOR]

The Siberian High (SH) is one of the most prominent wintertime circulation systems in the Northern Hemisphere. The variability of the intensity of the SH during the boreal winter has been extensively studied, while the reasons behind its formation remain largely elusive. This study investigates the interannual variation and underlying mechanisms of the SH formation, especially the three-dimensional circulation and associated surface boundary conditions. Early SH formation is usually accompanied by a Eurasian teleconnection (EU)-like pattern and a strengthened subtropical westerly jet, and opposite conditions are true for a delayed SH formation. Boundary conditions, including North Atlantic sea surface temperature (NASST) anomalies and the high-latitude Central Eurasia snow-cover extent (HCESCE) anomalies could modulate SH formation by affecting the overlying atmospheric circulations. Specifically, anomalously cold NASSTs can result in an anomalous equivalent barotropic anticyclone via diabatic heating and transient eddy forcing. Such an anomalous anticyclone and related divergence anomalies in the upper troposphere act as effective atmospheric Rossby sources, triggering a downstream propagating atmospheric teleconnection with a pattern similar to that of a positive EU-like wave train, favoring the early formation of the SH. In addition, the reduced HCESCE warms the overlying atmosphere, thus weakening the atmospheric baroclinicity and transient eddy activities over the SH region. These weakened eddy activities can intensify the EU-like pattern via vorticity forcing and strengthen the subtropical westerly jet via the eddy–mean flow interaction. The processes for the impacts of the NASST and HCESCE anomalies on the formation of the SH can be verified by a series of numerical simulations. [ABSTRACT FROM AUTHOR]

Multi-dimensional numerical simulations were performed to study the interactions between shock wave and premixed flame. The three-dimensional (3D) fully-compressible, reactive Navier–Stokes equations were solved using a high-order numerical method on a dynamically adapting mesh. The effect of wall friction on the shock–flame interaction was examined by varying wall boundary condition on sidewall. The simulations agree with previous experiment in terms of flame perturbation and flame evolution. The results show two effects of wall friction on flame–shock interaction: (1) flame stretching and (2) damping of local flame perturbation very close to the no-slip wall. The stretch effect leads to non-uniform development of the perturbated flame and consequently a significantly higher growth rate in both global flame perturbation and averaged pressure in the no-slip case compared to the free-slip case. By contrast, the damping effect locally moderates the flame perturbation in close proximity to the no-slip wall because less vorticity is deposited on this part of flame during shock–flame interaction. Quantitative analysis of vortex dynamics suggests that vorticity generation that is produced by baroclinic torque and enhanced by the dilation term during shock–flame interaction causes a growth of flame perturbation via Richtmyer–Meshkov instability. Nevertheless, the vorticity generation is greatly weakened in close proximity to the no-slip wall by the viscous torque and viscous dissipation terms due to friction. [ABSTRACT FROM AUTHOR]

We report on a novel fluid dynamics experiment configuration based on a modified version of the differentially heated rotating annulus, a widely used laboratory model of the large-scale mid-latitude atmospheric circulation. Through applying an azimuthally (zonally) inhomogeneous, dipole-like thermal boundary condition—imitating a permanent "day side" and "night side" in the rotating setting—we explore the character of the flow patterns emerging at different values of the zonal temperature contrast and rotation rate. This configuration may prove to be a useful minimal model of the large-scale atmospheric circulation of tidally locked exoplanets. [ABSTRACT FROM AUTHOR]

Turbulence is the most important, ubiquitous, and difficult problem of classical physics. Feynman viewed it as essentially unsolved, without a rigorous mathematical basis to describe the statistical dynamics of this most complex of fluid motion. However, the paradigm shift came in 1959, with the formulation of the Eulerian direct interaction approximation (DIA) closure by Kraichnan. It was based on renormalized perturbation theory, like quantum electrodynamics, and is a bare vertex theory that is manifestly realizable. Here, we review some of the subsequent exciting achievements in closure theory and subgrid modelling. We also document in some detail the progress that has been made in extending statistical dynamical turbulence theory to the real world of interactions with mean flows, waves and inhomogeneities such as topography. This includes numerically efficient inhomogeneous closures, like the realizable quasi-diagonal direct interaction approximation (QDIA), and even more efficient Markovian Inhomogeneous Closures (MICs). Recent developments include the formulation and testing of an eddy-damped Markovian anisotropic closure (EDMAC) that is realizable in interactions with transient waves but is as efficient as the eddy-damped quasi-normal Markovian (EDQNM). As well, a similarly efficient closure, the realizable eddy-damped Markovian inhomogeneous closure (EDMIC) has been developed. Moreover, we present subgrid models that cater for the complex interactions that occur in geophysical flows. Recent progress includes the determination of complete sets of subgrid terms for skilful large-eddy simulations of baroclinic inhomogeneous turbulent atmospheric and oceanic flows interacting with Rossby waves and topography. The success of these inhomogeneous closures has also led to further applications in data assimilation and ensemble prediction and generalization to quantum fields. [ABSTRACT FROM AUTHOR]

Oceanic submesoscales can significantly influence phytoplankton production and export owing to their similar timescales of days. Based on two-year Biogeochemical Argo (BGC-Argo) observations, this study investigated the development of submesoscale instabilities, particularly symmetric and mixed-layer baroclinic instabilities, and their impacts on biological production and export in the oligotrophic South China Sea basin. In the northern basin, near-surface winter blooms consistently cooccurred with seasonally deepened mixed layers. However, significantly stronger and weaker winter blooms were observed over two consecutive winters within the BGC-Argo observation period. During the first winter, symmetric-instability-induced upward nutrient entrainment played a crucial role in initiating the strong winter bloom in early December, when the mixed layer was approximately 20–30 m shallower than the nutricline. This bloom occurred approximately 20–30 days earlier than that anticipated owing to the contact between the seasonally deepened mixed layer and mesoscale-cyclone-induced uplifted nutricline. The symmetric instability also facilitated the export of fixed phytoplankton carbon from the surface to deeper layers. Conversely, during the second winter, remarkably intense mixed-layer baroclinic instability associated with an intense mesoscale anticyclone led to more significant shoaling of the mixed layer compared to the nutricline, thus increasing the vertical distance between the two layers. Under this condition, upward nutrient injection, phytoplankton bloom, and carbon export were suppressed. In contrast, the BGC-Argo float in the central basin revealed significantly inhibited seasonality of phytoplankton biomass and submesoscale instabilities compared to those in the northern basin, primarily owing to the significantly shallower winter mixed layer. [ABSTRACT FROM AUTHOR]

Low-mass planets migrating inwards in laminar protoplanetary discs (PPDs) experience a dynamical corotation torque (DCT), which is expected to slow down migration to a stall. However, baroclinic effects can reduce or even reverse this effect, leading to rapid inward migration. In the radiatively inefficient inner disc, one such mechanism is the buoyancy response of the disc to an embedded planet. Recent work has suggested that radiative cooling can quench this response, but for parameters that are not necessarily representative of the inner regions of PPDs. We perform global 3D inviscid radiation hydrodynamics simulations of planet–disc interaction to investigate the effect of radiative cooling on the buoyancy-driven torque in a more realistic disc model. We find that the buoyancy response exerts a negative DCT – albeit partially damped due to radiative cooling – resulting in sustained, rapid inward migration. Models that adopt a local cooling prescription significantly overestimate the impact of the buoyancy response, highlighting the importance of a realistic treatment of radiation transport that includes radiative diffusion. Our results suggest that low-mass planets should migrate inwards faster than has been previously expected in radiative discs, with implications for the formation and orbital distribution of super-Earths and sub-Neptunes at intermediate distances from their host stars, unless additional physical processes that can slow down migration are considered. [ABSTRACT FROM AUTHOR]

In this paper, we find a new regularity criterion of the 3D tropical climate model in terms of one component of the barotropic velocity. Our criteria of the velocity field improve the previous result by Berti et al. Moreover, we extend the regularity criteria of the Lebesgue spaces to that of larger Lorentz spaces. The key of this paper is by using interaction between partial and usual H1$$ {H}&#x0005E;1 $$ estimate to get upper bound of velocities. [ABSTRACT FROM AUTHOR]

The Southern Annular Mode (SAM) is the predominant mode of climate variability across the Southern Hemisphere (SH) extratropical region. During the late 20th century, the SAM has undergone a remarkable positive trend, particularly pronounced in austral summer (December-January-February, DJF), which is mainly attributed to the ozone depletion in Antarctic stratosphere. However, 42 state-of-the-art models archived in CMIP6 exhibit noteworthy inter-model spread of the simulated long-term trend of the DJF SAM, with an inter-model standard deviation of 0.19 (per decade) both in AMIP and historical experiments. This study aims to explore the potential sources of model uncertainty in simulating the DJF SAM trend. Corresponding results from AMIP experiments indicate that the dominant mode of SH extratropical sea surface temperature (SST), namely the Southern Ocean Dipole (SOD), plays an important role in model performance in reproducing the SAM variability. Models with stronger linkage between the SOD and the SAM tend to simulate a more positive trend as well as a more realistic inter-annual variability of the DJF SAM, the averaged explained variance is over 30% in AMIP experiment. The possible reason for the inter-model uncertainty in depicting the responses of the SAM to the SOD in DJF could be explained by the different sensitivities of atmospheric baroclinicity in middle and high latitudes to the underlying SST anomalies in each model, which may be associated with the internal processes of the climate system. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a specific modification of the numerical fluxes in order to insure the well-balanced property of schemes on staggered grids for the Euler equations. This property is crucial for the numerical representation of equilibrium solutions of balance laws with source terms, like when describing flows subjected to gravity and a complex topography. We propose first and second order versions of the well-balanced scheme. The performances of the method are evaluated through a series of 1D and 2D benchmarks. [ABSTRACT FROM AUTHOR]

Mesoscale eddies modulate the stratification, mixing, tracer transport, and dissipation pathways of oceanic flows over a wide range of spatiotemporal scales. The parameterization of buoyancy and momentum fluxes associated with mesoscale eddies thus presents an evolving challenge for ocean modelers, particularly as modern climate models approach eddy‐permitting resolutions. Here we present a parameterization targeting such resolutions through the use of a subgrid mesoscale eddy kinetic energy budget (MEKE) framework. Our study presents two novel insights: (a) both the potential and kinetic energy effects of eddies may be parameterized via a kinetic energy backscatter, with no Gent‐McWilliams along‐isopycnal transport; (b) a dominant factor in ensuring a physically‐accurate backscatter is the vertical structure of the parameterized momentum fluxes. We present simulations of 1/2° and 1/4° resolution idealized models with backscatter applied to the equivalent barotropic mode. Remarkably, the global kinetic and potential energies, isopycnal structure, and vertical energy partitioning show significantly improved agreement with a 1/32° reference solution. Our work provides guidance on how to parameterize mesoscale eddy effects in the challenging eddy‐permitting regime. Plain Language Summary: Ocean eddies evolving on horizontal lengthscales of order 10–100 km are not sufficiently resolved in modern global ocean models that have horizontal resolutions of about 25–100 km. The under‐representation of such eddies leads to inaccuracies in the modeled ocean state, including weakened current systems, incorrect stratification, and erroneous distributions of physical and biological ocean tracers. Here we develop a novel approach to mimicking the unresolved eddy effects by artificially energizing the flow in a way that is consistent with eddy dynamics, specifically their vertical structure. We find that our approach is able to correct for a variety of unresolved eddy effects when employed in a coarse‐resolution ocean model and compared against a high‐resolution reference case. Our work provides new insights on how to account for unresolved eddies in the next generation of climate models. Key Points: We propose a parameterization for mesoscale eddies targeting ocean models at eddy‐permitting resolutionsWe find that both the potential and kinetic energy effects of eddies on the flow may be parameterized via a kinetic energy backscatterThe novel approach of our backscatter scheme is its use of vertical structure, that is, backscattering onto the equivalent barotropic mode [ABSTRACT FROM AUTHOR]

Cut-off lows (COLs) exhibit diverse structures and lifecycles, ranging from confined upper-tropospheric systems to deep, multi-level vortex structures. While COL climatologies are well documented, the mechanisms driving their deepening remain unclear. To bridge this gap, a novel track matching algorithm applied to ERA-Interim reanalysis investigates the vertical extent of Southern Hemisphere COLs. Composite analysis based on structure and eddy kinetic energy budget differentiates four COL categories: shallow, deep, weak, and strong, revealing similarities and disparities. Deep, strong COLs concentrate around Australia and the southwestern Pacific, peaking in autumn and spring, while shallow, weak COLs are more common in summer and closer to the Equator. Despite their differences, both contrasting types evolve energetically via anticyclonic Rossby wave breaking. The distinct roles of jet streams in affecting COL types are addressed: intense polar front jets correlate with more deep COLs, whereas stronger subtropical jets relate to fewer shallow COLs. The COL deepening typically occurs in the presence of a robust upstream polar front jet, which enhances ageostrophic flux convergence and baroclinic processes. The subtropical jet positively correlates with COL intensity but weakens when considering the seasonality, suggesting uncertainties in this relationship. Additionally, we highlight the significance of diabatic processes in COL deepening, addressing their misrepresentation in reanalysis and emphasizing the need for more observational and modelling studies to refine the energetic framework. [ABSTRACT FROM AUTHOR]

Introduction: In this study, we aimed to investigate the effect of daily meteorological parameters on the number of patients applying to the emergency department as a result of exposure to aggressive behavior. Methods: In our retrospectively planned study, patients who were admitted to the university hospital emergency department between January 1, 2012, and December 31, 2021, due to stab wounds, gunshot wounds, and assault were included in the study. The relationship between the meteorological parameters, including air temperature, atmospheric pressure, relative humidity, and maximum wind speed on the admission days of these patients, was analyzed. Results: In the study, a total of 7825 patients admitted due to stab wounds (n=1110), gunshot wounds (n=681), and assault (n=6034) were included. The highest number of applications to the emergency department due to exposure to physical violence were on Fridays (n=1225, 16%) and in August (n=780, 10%), and the lowest applications were on Sundays (n=1014, 13%) and in February (n=428, 6%). According to the results of the Poisson regression analysis of the relationship between patient applications and daily measurement parameters, average relative humidity and average wind speed were found to be independent determinants for stab wounds and gunshot wounds, and average temperature and average wind speed were found to be independent determinants for assault. Discussion and Conclusion: Meteorological parameters such as air temperature, relative humidity, air pressure, and maximum wind speed affect exposure to aggressive behavior and the need for emergency healthcare. [ABSTRACT FROM AUTHOR]

Extreme low-temperature frosts occurred in eastern Aksu Prefecture, Xinjiang, China on April 23 and May 6, 2023 ("4.23"process and"5.6"process for short, respectively). Particularly, the latest frost in history appeared in Kuqa City during the"5.6"process. In this study, based on conventional observation data, L- band sounding data, and 6-h reanalysis data of NCEP/NCAR 1°x1°, we contrastively analyze the circulation background, circulation configurations of high and low altitudes, cold air intensity, cold advection intensity, and frontogenesis during two extreme low- temperature processes using weather dynamics. Moreover, the causes of extreme low-temperature frosts are discussed. We realized both common characteristics and differences between the two processes. (1) The common characteristics are as follows: The temperature of eastern Aksu at 500 hPa is affected by northwest flow with cold air at the back of the low trough (low vortex), with a great temperature gradient and strong frontal zone during the two processes. Deep cold advection flows from the upper level of western Aksu to the lower level of eastern Aksu along the northern flow. Temperature inversion and obvious frontogenesis occur in the near-surface layer during the low-temperature period. Frontogenesis corresponds to the path of cold air entering the southern Xinjiang basin and the low- temperature duration. In addition, the upper- level energy frontal zone is stronger, and the mid-low-level energy frontal zone gradually strengthens with baroclinic instability. The cold advection intensity increases to a maximum of 6 h before frost. The cold advection can significantly decrease the temperature of the Aksu area from above 8 °C to 3-4 °C at 850 hPa, indicating strong frost. (2) The differences are as follows: The cold air invades the Aksu Prefecture from the northwest path in the"4.23"process. The air temperature in the Aksu Prefecture is affected by both"Xifan (flowing over the mountains from west)" and "Dongguan (injecting from east)"cold air. The temperature inversion in the near-surface layer is enhanced by radiation and advection cooling. However, the cold air passes over Tianshan Mountains with a strongly cold high pressure and then invades the southern Xinjiang basin from the northern path in the"5.6"process, accompanied by"Dongguan"cold air. The influence range is large, and the temperature inversion is weak. Howev- er, the temperature of the entire layer is significantly reduced, mainly via radiation cooling. (3) The low vortex of the"5.6"process lasts for a long time in Xinjiang. The cold air and frontal zone intensity, potential pseudo-equivalent temperature gradient, and influence time are stronger than those of the"4.23"process, resulting in a more severe disaster. [ABSTRACT FROM AUTHOR]

Submesoscale process is an important part in the kinetic energy cascade from large‐scale circulation to turbulent dissipation, and a key component of the global heat budget. Its dynamic response to weather event is an important process in forecasting marine bio‐chemical matter transport. So how will submesoscale instabilities response to tropical cyclones (TCs) is worth studying. Based on underwater glider observations and 1‐km high resolution numerical modeling, we investigated two TCs (Roke and Haitang)‐induced submesoscale baroclinic instabilities and their dynamic mechanisms in the Northern South China Sea. The TC Haitang induced significant surface cooling, mixed layer deepening, front sharpening, and enhanced the mixed layer baroclinic and symmetric instabilities. The submesoscale kinetic energy also enhanced sharply after TC Haitang, which was higher correlated with increased mesoscale strain rates. The submesoscale energetics analysis revealed that the enhanced frontal submesoscale kinetic energy after TC Haitang was mainly from potential energy release via baroclinic energy conversion. Four groups of sensitivity numerical experiments revealed that the turbulent heat buoyancy flux and the Ekman buoyancy flux contributed equally to the positive baroclinic energy conversion during the TC Haitang. This study helps us to understand the multiscale oceanic energy transfers and submesoscale air‐sea interaction processes. Plain Language Summary: The oceanic submesoscale process has scale ranges with 0.1–10 km in the horizontal, 0.01–1 km in the vertical, and hours‐days in time. The submesoscale process is a key component of the global energy balance and the heat budget, and can be generated by the atmosphere forcing, for example, cold weather, tropical cyclones (TCs). Based on 2‐km high resolution underwater glider and our set‐up 1‐km numerical modeling data, we found TC Haitang could trigger submesoscale symmetric instability and mixed layer baroclinic instabilities. The former instability gains kinetic energy from geostrophic currents, and the latter draw energy from the mesoscale flow potential energy in the northern South China Sea. The frontal submesoscale kinetic energies (KEs) enhanced sharply after TC Haitang. Based on the submesoscale kinetic energy budget analysis, we suggested that the enhanced frontal KEs after TC Haitang was transferred from potential energy via mixed layer baroclinic energy conversion. After conducting four groups of sensitivity numerical experiments, we found that the turbulent heat buoyancy flux and the Ekman buoyancy flux contributed to the strong vertical buoyancy fluxes during the TC Haitang. This study improves our understanding in submesoscale air‐sea interaction. Key Points: Both the submesoscale frontogenetic function and kinetic energy got enhanced after tropical cyclone (TC) HaitangThe enhanced submesoscale kinetic energy after TC Haitang was primarily dominated by the mixed layer baroclinic instabilityThe vertical buoyancy fluxes were mainly induced by turbulent heat and Ekman buoyancy fluxes during TC Haitang [ABSTRACT FROM AUTHOR]

This study identified four patterns of regional extreme precipitation events (REPEs) in Central Asia (CA) and their crucial synoptic systems and multiscale interactions. Four patterns with distinct spatial distributions were identified in: northern Kazakhstan, southern Xinjiang, western CA, and the Tianshan Mountains. Focusing on the three most frequent REPEs, the kinetic energy (KE) cross‐scale transfer from the basic‐to synoptic‐scale windows exhibited a zonal dipole, resulting in the development and enhancement of REPEs in northern Kazakhstan. The available potential energy (APE) cross‐scale transfer exhibited opposing patterns between the upper and lower troposphere, indicating baroclinic instability in the lower troposphere and barotropic instability of the basic flow in the upper troposphere. Both mechanisms enhanced the Central Asian vortices (CAVs) in southern Xinjiang and induced REPEs. Conversely, the energy budgets exhibited baroclinic instability of the basic flow throughout the entire region when the Tianshan Mountains REPEs occurred, providing energy for prevalent CAVs. Plain Language Summary: A self‐organizing map was employed to classify the regional extreme precipitation events (REPEs) in Central Asia (CA) into four patterns with unique spatial distributions (northern Kazakhstan: P1, southern Xinjiang: P2, western CA: P3, and Tianshan Mountains: P4). This study further illuminated the multiscale interaction mechanisms for the development of key synoptic systems that generate REPEs for the three most frequent patterns (P1, P2, and P4). A zonal dipolar kinetic energy (KE) cross‐scale transfer occurred throughout the region in P1, resulting in the development of a long‐wave trough and the enhancement of REPEs. P2 is characterized by a negative eastward shift of the North Atlantic Oscillation‐like in the original field and the reconstructed intraseasonal‐scale field, which promotes the development of Central Asian vortices (CAVs) over southern Xinjiang. The available potential energy (APE) and KE cross‐scale transfer from the basic‐to synoptic‐scale windows indicate that baroclinic and barotropic instability occur in the lower and upper troposphere, respectively. Thus, providing sufficient energy and dynamic conditions for CAVs enhances REPEs. Furthermore, the Silk Road pattern‐like dominates over Eurasia, and CAVs occur over the northwestern Tianshan Mountains, as observed in P4. APE cross‐scale transfer induces strong baroclinic instability throughout the troposphere and provides energy for more prevalent CAVs that intensify the REPEs. Key Points: The long‐wave trough and Central Asia (CA) vortex are the crucial synoptic systems of summer regional extreme precipitation in CAThe crucial synoptic systems are powered by the basic‐ and intraseasonal‐scale baroclinic instabilityThe spatial inconsistency of local multiscale interactions affects the formation of the crucial synoptic systems and extreme precipitation [ABSTRACT FROM AUTHOR]

Objective : Acute pharyngitis is common worldwide. Meteorological changes contribute to respiratory infections. This study aims to explore the correlation between acute pharyngitis and meteorological parameters. Methods : We collected the monthly acute pharyngitis cases in our hospital and the meteorological data, including temperature, relative humidity, and air quality index (AQI) of Shanghai, China, from January, 2015, to December, 2017. Pearson correlation and multivariable regression analysis were used to explore the association between meteorological parameters and the monthly hospital visits. Results : A total of 8287 patients were included in this study, and the monthly number of hospital visits was 230.2 ± 39.0. The best air quality index was 46.4 and the worst was 113.2. Temperature ranged from 5.2°C to 32.0°C, and relative humidity ranged from 59.4% to 83.1%. The monthly hospital visits of acute pharyngitis were negatively correlated with temperature (r = −.558, 95% CI −.746, −.274) and relative humidity (r = −.480, 95% CI −.695, −.137). A decrease of 1°C could cause an increase in hospital visits by 1.9. No significant correlation was found were found between acute pharyngitis cases and AQI (P =.051, 95% CI −.005,.590). Multivariable linear regression analysis showed the temperature was the independent risk factor of acute pharyngitis (coefficient = −1.906, P =.022). Conclusion : Low temperature might cause an increased incidence of acute pharyngitis. [ABSTRACT FROM AUTHOR]

This article continues and generalizes the study "On the Similarity of Quasi-Geostrophic Vortices against the Background of Large-Scale Barotropic Currents" [6] (Oceanology, Zhmur, 2024, in print). In continuation of [6], a similar formulation is considered, but for other types of background currents. In the quasi-geostrophic description for small Rossby numbers, the problem of the evolution of an arbitrarily shaped liquid volume with homogeneous potential vorticity of all vortex core particles in an equidistant background flow—horizontal flow with vertical shear and equidistant flow with barotropic and baroclinic components—is presented. Ultimately, the problem boils down to an integrodifferential equation for the evolution of the vortex core boundary. The study of this equation in dimensionless form makes it possible to find a set of dimensionless parameters that determine the similarity condition of the studied vortices. [ABSTRACT FROM AUTHOR]

Motivated by the phenomenon of Scotian Shelf Crossover events, the problem of a shelf flow that is interrupted by a strait is considered. Laboratory experiments in a rotating tank with barotropic and baroclinic flow over flat and sloping shelves confirm that the flow is steered by the bathymetric contours and mainly circumnavigates the gulf. In order to jump across the strait, as suggested by earlier theories, the flow must have unrealistically high Rossby numbers. However, the near bottom friction relaxes the bathymetric constraint and causes the formation of a peculiar jet crossing the strait diagonally. For the dissipation values such that a half of the transport goes around the gulf and half crosses the strait diagonally, the diagonal crossover jet becomes most evident. Numerical solutions for realistic values of the frictional parameter reproduce the results of the laboratory experiments and consideration of the actual Gulf of Maine bathymetry reproduces patterns similar to those observed by drift trajectories and in the satellite derived sea surface temperature fields. [ABSTRACT FROM AUTHOR]

Along with the familiar Rossby–Haurwitz waves, two-dimensional flows on the surface of a rotating sphere in the regime of zonostrophic turbulence harbor another class of waves known as zonons. Zonons are wave packets produced by energetic large-scale Rossby–Haurwitz wave modes 'enslaving' other wave modes. They propagate westward with the phase speed of the enslaving modes. Zonons can be visualized as enslaving modes' 'ringing' in the enslaved ones with the frequencies of the former, the property that renders zonons non-dispersive. Zonons reside in high-shear regions confined between the opposing zonal jets yet they are mainly attached to westward jets and sustained by the ensuing barotropic instability. They exchange energy with the mean flow while preserving their identity in a fully turbulent environment, a feature characteristic of solitary waves. The goal of this study is to deepen our understanding of zonons' physics using direct numerical simulations, a weakly non-linear theory, and asymptotic analysis, and ascertain that zonons are indeed isomorphic to solitary waves in the Korteweg–de Vries framework. Having this isomorphism established, the analysis is extended to eddies detected in the atmospheres of Jupiter and Saturn based upon the observed mean zonal velocity profiles and earlier findings that circulations on both planets obey the regime of zonostrophic macroturbulence. Not only the analysis confirms that many eddies and eddy trains on both giant planets indeed possess properties of zonons, but the theory also correctly predicts latitudinal bands that confine zonal trajectories of the eddies. [ABSTRACT FROM AUTHOR]

The equatorial region of the Earth's atmosphere serves as both a significant locus for phenomena, including the Madden–Julian Oscillation (MJO), and a source of formidable complexity. This complexity arises from the intricate interplay between nonlinearity and thermodynamic processes, particularly those involving moisture. In this study, we employ a normal mode decomposition of atmospheric reanalysis ERA-5 datasets to investigate the influence of nonlinearity and moisture on amplitude growth, propagation speed, and mode coupling associated with equatorially trapped waves. We focus our analysis on global-scale baroclinic Kelvin and Rossby waves, recognized as crucial components contributing to the variability of the MJO. We examine the dependence of wave amplitudes on the background moisture field in the equatorial region, as measured by total column water vapor. Our analysis demonstrates the crucial role of moisture in exciting these waves. We further investigate the dependence of the propagation speed of the waves on their amplitudes and the background moisture field. Our analysis reveals a robust correlation between the phase speed of the normal modes and their corresponding amplitude, whereas a weaker correlation is found between the eigenmodes' phase speed and the moisture field. Hence, our findings suggest that moisture plays a role in exciting the global-scale Rossby–Kelvin structure of the MJO. In this context, the propagation speed of the eigenmodes is mainly influenced by their amplitudes, underscoring the significant role of nonlinearity in wave propagation. [ABSTRACT FROM AUTHOR]

This study aimed to determine if air pollution affected the risk of periodontitis outpatient visits. We collected the records of 56,456 periodontitis outpatient visits in Hefei, China, from January 1, 2014 to December 31, 2021. The relationship between air pollution and periodontitis outpatient visits was evaluated using distributed lag nonlinear and generalized linear models. Additional analyses were performed, stratifying the data by age, season, and sex. Subgroup analyses showed a significantly higher risk of periodontitis outpatient visits due to NO2 exposure during the warm season compared with the cold season. Moreover, O3 exposure was associated with a lower risk of periodontitis outpatient visits in the cold season. The findings suggest that NO2 exposure is associated with an increased risk of periodontitis outpatient visits, whereas O3 exposure is associated with a decreased risk of periodontitis outpatient visits. Season is found to be an effect modifier in these associations. [ABSTRACT FROM AUTHOR]

In this work, we consider a Shallow‐Water Quasi Geostrophic equation on the sphere, as a model for global large‐scale atmospheric dynamics. This equation, previously studied by Verkley (2009, https://doi.org/10.1175/2008jas2837.1) and Schubert et al. (2009, https://doi.org/10.3894/james.2009.1.2), possesses a rich geometric structure, called Lie‐Poisson, and admits an infinite number of conserved quantities, called Casimirs. In this paper, we develop a Casimir preserving numerical method for long‐time simulations of this equation. The method develops in two steps: first, we construct an N‐dimensional Lie‐Poisson system that converges to the continuous one in the limit N → ∞; second, we integrate in time the finite‐dimensional system using an isospectral time integrator, developed by Modin and Viviani (2020, https://doi.org/10.1017/jfm.2019.944). We demonstrate the efficacy of this computational method by simulating a flow on the entire sphere for different values of the Lamb parameter. We particularly focus on rotation‐induced effects, such as the formation of jets. In agreement with shallow water models of the atmosphere, we observe the formation of robust latitudinal jets and a decrease in the zonal wind amplitude with latitude. Furthermore, spectra of the kinetic energy are computed as a point of reference for future studies. Plain Language Summary: We conducted a study on a model that represents the movements of planetary flows. This model has important physical and mathematical properties that are related to its long‐term behavior, which is essential for understanding geophysical turbulence. In this work, we developed a numerical method for simulation that preserves the key mathematical structure of the model through a two‐step process. We applied our method to simulate global atmospheric flow and investigate the impact of varying strengths of planetary rotation. Our findings demonstrate the expected formation of wind patterns known as zonal jets, where stronger winds occur near the equator and weaker winds near the poles. We also present energy spectra that illustrate the influence of planetary rotation on the transfer of turbulent energy, which aligns with existing theoretical predictions found in literature. These results highlight the potential of our numerical method for studying fundamental problems in geophysical fluid dynamics. Key Points: We develop a numerical method preserving Casimirs to simulate balanced shallow water flow on the sphereWe perform global high‐resolution simulations while accurately accounting for latitude‐dependent effectsOur simulations show the formation of robust zonal jets and provide key insights into quasi‐geostrophic turbulence [ABSTRACT FROM AUTHOR]

In recent years, extreme weather events associated with atmospheric blocking in the northern extratropics have become more frequent. This study has revealed the impacts of the stratospheric polar vortex on the blockings over the North Atlantic sector, using both reanalysis data and large-ensemble experiments performed by general circulation model. It is found that a weak stratospheric polar vortex (WPV) can cause more blockings to be generated over Greenland and move more westward than normal, while a strong stratospheric polar vortex (SPV) can cause more blockings to be generated over the south of Greenland and Western Europe. The stratospheric polar vortex could influence blocking anomalies by modulating both synoptic-scale eddy and planetary wave activities. Under WPV conditions, the generation of synoptic-scale eddies is suppressed due to decreased upper-troposphere background baroclinicity, which is favorable for positive geopotential height anomalies and more blockings over Greenland. Additionally, WPV can suppress the planetary wave train that is accompanied with lower pressure center over Greenland, further contributing to the positive geopotential height anomalies and more blockings over Greenland. The abovementioned processes under SPV conditions are nearly opposite to those under WPV conditions. [ABSTRACT FROM AUTHOR]

This study explores the effect of submesoscale topography on baroclinic instability under the quadric shear basic zonal flow is discussed. On the beta plane approximation, the quasi-geostrophic model is used for numerical simulation, and the multiscale model to discuss and verify this problem. A multiscale framework is used to explain the interaction between mesoscale eddies, submesoscale variability, and topographic effects. The multiscale method makes it possible to express the dynamic characteristics of the governing equations with a set of closed systems containing only mesoscale variables. It is found that the interaction between submesoscale topography and baroclinic instability affects some characteristics of mesoscale variability, such as promoting the formation of mesoscale eddies. and the energy and momentum transport of eddies. [ABSTRACT FROM AUTHOR]

We propose in this article a discretization of the momentum convection operator for fluid flow simulations on quadrangular or generalized hexahedral meshes. The space discretization is performed by the low‐order nonconforming Rannacher–Turek finite element: the scalar unknowns are associated with the cells of the mesh while the velocities unknowns are associated with the edges or faces. The momentum convection operator is of finite volume type, and its expression is derived, as in MUSCL schemes, by a two‐step technique: (i)$$ (i) $$ computation of a tentative flux, here, with a centered approximation of the velocity, and (ii)$$ (ii) $$ limitation of this flux using monotonicity arguments. The limitation procedure is of algebraic type, in the sense that its does not invoke any slope reconstruction, and is independent from the geometry of the cells. The derived discrete convection operator applies both to constant or variable density flows and may thus be implemented in a scheme for incompressible or compressible flows. To achieve this goal, we derive a discrete analogue of the computation ui(∂t(ρui)+div(ρuiu)=12∂t(ρui2)+12div(ρui2u)$$ {u}_i\kern0.3em \Big({\partial}_t\left(\rho {u}_i\right)+\operatorname{div}\left(\rho {u}_i\boldsymbol{u}\right)=\frac{1}{2}{\partial}_t\left(\rho {u}_i^2\right)+\frac{1}{2}\operatorname{div}\left(\rho {u}_i^2\boldsymbol{u}\right) $$ (with u$$ \boldsymbol{u} $$ the velocity, ui$$ {u}_i $$ one of its component, ρ$$ \rho $$ the density, and assuming that the mass balance holds) and discuss two applications of this result: first, we obtain stability results for a semi‐implicit in time scheme for incompressible and barotropic compressible flows; second, we build a consistent, semi‐implicit in time scheme that is based on the discretization of the internal energy balance rather than the total energy. The performance of the proposed discrete convection operator is assessed by numerical tests on the incompressible Navier–Stokes equations, the barotropic and the full compressible Navier–Stokes equations and the compressible Euler equations. [ABSTRACT FROM AUTHOR]