Diurnal Variation Research Articles

Diurnal Variations in Tropical Cyclone Formation and Associated Convective Features

AbstractThis study investigates the diurnal variations in the formation of tropical cyclones (TCs) and their linkage to convective features. Using best‐track data from 2001 to 2020, it was found that TC formation shows a clear diurnal variation, peaking between 0300 and 0900 local solar time (LST) in most regions. Before a TC forms, the radial gradient in infrared (IR) brightness temperatures (BT) is mainly influenced by the expansion of clouds with IR BT below 208 K. These clouds are most abundant between 0300 and 0600 LST and least abundant between 1500 and 1800 LST. Clouds within 200 km of the circulation center have a higher fraction and greater diurnal variation compared to those located at radii of 200–500 km. A higher fraction of early morning clouds with IR BT < 208 K within 200 km of the circulation center increases the radial IR BT gradient, enhancing the likelihood of TC formation during morning hours.

Longitudinal trajectories of sleep inertia among intern nurses with shift work in China: Prevalence, risk factors and outcomes.

There is a growing consensus regarding the significant individual differences in responses to sleep inertia. However, little is known about the longitudinal trajectories of sleep inertia. Therefore, we aimed to investigate the incidence rates of sleep inertia, longitudinal trajectories, influencing factors and outcomes among intern nurses with shift work. A total of 1079 intern nurses with shift work completed online surveys at 2 weeks (T1) and 16 weeks (T2) after their clinical internship, respectively. The demographics and willingness to continue working as nurses, circadian type, sleep problems and emotional problems were measured. Hierarchical logistic regressions were used to examine predictors for the distinct longitudinal trajectory of sleep inertia, and binary logistic regressions were used to examine the predictive effects of trajectory memberships of sleep inertia on mental health problems (daytime sleepiness, anxiety, depression) at follow-up. Overall, the incidence rates of severe sleep inertia increased significantly from 20.4% at T1 to 25.3% at T2 among intern nurses with shift work. All participants were classified into four trajectory memberships. Multiple factors were significant predictors of distinct trajectories of sleep inertia. Additionally, individuals with deteriorated and persistent-high sleep inertia were more likely to develop mental health problems at the subsequent point. Sleep inertia is prevalent among intern nurses with shift work, and its distinct change patterns were associated with multiple risk factors and various adverse outcomes. Therefore, these factors should be considered when designing individualized and appropriate interventions for sleep inertia among medical staff.

Research on Climate Drivers of Ecosystem Services’ Value Loss Offset in the Qinghai–Tibet Plateau Based on Explainable Deep Learning

As one of the highest and most ecologically vulnerable regions in the world, the Qinghai–Tibet Plateau (QTP) presents significant challenges for the application of existing ecosystem service value (ESV) assessment models due to its extreme climate changes and unique plateau environment. Current models often fail to adequately account for the complex climate variability and topographical features of the QTP, making accurate assessments of ESV loss deviations difficult. To address these challenges, this study focuses on the QTP and employs a modified ESV loss deviation model, integrated with explainable deep learning techniques (LSTM-SHAP), to quantify and analyze ESV loss deviations and their climate drivers from 1990 to 2030. The results show that (1) between 1990 and 2020, the offset index in the eastern QTP consistently remained low, indicating significant deviations. Since 2010, low-value clusters in the western region have significantly increased, reflecting a widening range of ecological damage caused by ESV losses, with no marked improvement from 2020 to 2030. (2) SHAP value analysis identified key climate drivers, including temperature seasonality, diurnal temperature variation, and precipitation patterns, which exhibit nonlinear impacts and threshold effects on ESV loss deviation. (3) In the analysis of nonlinear relationships among key climate drivers, the interaction between diurnal temperature range and precipitation in wet seasons demonstrated significant effects, indicating that the synergistic action of temperature variation and precipitation patterns is critical to ecosystem stability. Furthermore, the complex nonlinear interactions between climate factors exacerbated the volatility of ESV loss deviations, particularly under extreme climate conditions. The 2030 forecast highlights that wet season precipitation and annual rainfall will become key factors driving changes in ESV loss deviation. By combining explainable deep learning methods, this study advances the understanding of the relationship between climate drivers and ecosystem service losses, providing scientific insights for ecosystem protection and sustainable management in the Qinghai–Tibet Plateau.

Validation of millimetre and sub-millimetre atmospheric collision-induced absorption at Chajnantor

Due to the importance of a reference atmospheric radiative transfer model for both planning and calibrating ground-based observations at millimetre and sub-millimetre wavelengths, we have undertaken a validation campaign consisting of acquiring atmospheric spectra under different weather conditions, in different diurnal moments and seasons, with the Atacama Pathfinder EXperiment (APEX), due to the excellent stability of its receivers and the very high frequency resolution of its back-ends. As a result, a dataset consisting of 56 spectra within the 157.3-742.1 GHz frequency range, at kilohertz resolution (smoothed to sim 2-10 MHz for analysis), and spanning one order of magnitude (sim 0.35-3.5 mm) in precipitable water vapour columns, has been gathered from October 2020 to September 2022. These data are unique for their quality and completeness and, due to the proximity of APEX to the Atacama Large Millimeter/Submillimeter Array (ALMA), they provide an excellent opportunity to validate the atmospheric radiative transfer model currently installed in the ALMA software. The main issues addressed in the study are possible missing lines in the model, line shapes, vertical profiles of atmospheric physical parameters and molecular abundances, seasonal and diurnal variations, and collision-induced absorption (CIA), to which this paper is devoted, in its N$_2$-N$_2$ + N$_2$-O$_2$ + O$_2$-O$_2$ (dry) and N$_2$-H$_2$O + O$_2$-H$_2$O (`foreign' wet) mechanisms. All these CIA terms should remain unchanged in the above-mentioned ALMA atmospheric model as a result of this work.

A revised ocean mixed layer model for better simulating the diurnal variation in ocean skin temperature

Abstract. Sea surface temperature (SST) is a crucial parameter in climate, weather, and ocean sciences due to its decisive role in ocean–atmosphere interactions. Identifying errors in the prognostic scheme used by the current European Centre for Medium-range Weather Forecasts (ECMWF) model for predicting the diurnal variation in ocean skin temperature led to a revisit and revision of the ocean mixed layer (OML) model. Validation of the revised model was conducted by comparing simulated temperatures at the sub-skin level and 1 m depth with observations from shipborne infrared measurements and buoys. These comparisons revealed a strong correlation, with an absolute mean deviation of less than 0.1 K and a standard deviation under 0.5 K, which are found to be comparable to errors in satellite observations of SST. Given that these results are derived from the same model simulations, the error statistics for the simulated skin temperature and its diurnal variation should have the same degree of accuracy. Furthermore, the simulation results closely align with anticipated solar radiation distributions, whereas ERA5 ocean skin temperature shows a significant lack of alignment with solar radiation. Consequently, the revised OML model shows promising potential for improving the simulation of diurnal SST variations in weather and climate models.

Effect of double-layer formwork curing on the early temperature field and properties of precast concrete components in environments with large diurnal temperature variations

An efficient double-layer formwork curing method using an “inner supporting formwork + outer insulation formwork” was proposed in this study to address the early cracking of precast concrete components in high altitude regions. Steel and plywood formwork were designed as inner support formwork, while polystyrene (PS) and polyurethane (PU) were used as outer insulation formwork. Indoor experiments and two finite element methods (The complete simulation method focuses on computational accuracy, and the equivalent simulation method emphasizes computational efficiency) were employed to analyze the evolution of the concrete temperature field under different double-layer formwork curing methods throughout the curing period, combined with compressive strength and pore structures testing. The results show that steel + 5-mm-thick PU insulation formwork curing method can significantly mitigate the impact of large diurnal temperature variations on the internal temperature of concrete. Unlike traditional steam-curing, this method does not deteriorate the pore structure or compressive strength of the concrete. This study is of great significance in addressing the problem of early cracking of precast concrete components exposed to large diurnal temperature vriations in high altitude regions.

Characteristics of Atmospheric Circulation Patterns and the Associated Diurnal Variation Characteristics of Precipitation in Summer over the Complex Terrain in Northern Xinjiang, Northwest China

Statistical characteristics of atmospheric circulation patterns (ACPs) and associated diurnal variation characteristics (DVCs) of precipitation in summer (June–August) from 2015 to 2019 over the complex terrain in northern Xinjiang (NX), northwestern arid region of China, were investigated based on NCEP FNL reanalysis data and Weather Research and Forecasting model simulation data from Nanjing University (WRF-NJU). The results show that six different ACPs (Type 1–6) were identified based on the Simulated ANealing and Diversified RAndomization (SANDRA), exhibiting significant differences in major-influencing synoptic systems and basic meteorological environments. Types 5, 3, and 2 were the most prevalent three patterns, accounting for 21.6%, 19.7%, and 17.7%, respectively. Type 5 mainly occurred in June and July, while Types 3 and 2 mainly occurred in August and July, respectively. From the perspective of DVCs, Type 1 reached its peak at midnight, while Type 5 was most frequent in the afternoon and morning. The overall DVCs of hourly precipitation intensity and frequency demonstrated a unimodal structure, with a peak occurring at around 16 Local Solar Time (LST). Basic meteorological elements in various terrain regions exhibit significant diurnal variation, with marked differences between mountainous and basin areas under different ACPs. In Types 3 and 6, meteorological elements significantly influence precipitation enhancement by promoting the convergence and uplift of low-level wind fields and maintaining high relative humidity (RH). The Altay Mountains region and Western Mountainous regions experience dominant westerly winds under these conditions, while the Junggar Basin and Ili River Valley regions benefit from counterclockwise water vapor transport associated with the Iranian Subtropical High in Type 6, which increases RH. Collectively, these factors facilitate the formation and development of precipitation.

Spatial and Temporal Variation of Nutrient Distribution in the Yangtze River Estuary and Adjacent Waters: Insights from GOCI Data Analysis

Nutrients are critical in assessing water quality, so understanding their distribution and variability is essential for effective marine environmental protection. This study focuses on the Yangtze River estuary and surrounding waters, where suspended solids show a strong correlation with active phosphates and silicates. Using GOCI imagery and measured nutrient concentrations, such as active phosphate and silicate, remote sensing models were developed to investigate the seasonal and daily changes in surface water nutrients. The results showed the following key findings: Temporally, active phosphate (PO4-P) and silicate (SiO3-Si) concentrations exhibited distinct seasonal patterns, with the highest values observed in winter (1.692 μmol/L and 16.386 μmol/L, respectively) and the lowest in summer (0.503 μmol/L and 10.645 μmol/L, respectively). Little difference was found between spring and autumn. Spatially, elevated phosphate and silicate concentrations were found near the northern Jiangsu Shoal, the Yangtze River estuary, and Hangzhou Bay, and decreased towards the outer coastal waters. This suggests that the freshwater inflow from the Yangtze River is an important driver of the observed nutrient patterns. Diurnal variations in phosphate and silicate concentrations were observed in the surface waters of the Yangtze River estuary and adjacent areas. Significant diurnal variations in nutrient concentrations were observed in Hangzhou Bay, the northern part of the Yangtze River estuary and the southern part of the Yangtze River estuary. Slight diurnal variations were observed in the inland channels of the estuary. These results help to facilitate the study of the complex process of spatial and temporal dynamics of nutrients in the coastal waters of eastern China.

Comparison between the ECG Outcomes of Metoprolol and Bisoprolol.

Beta-blockers are essential agents in the management of cardiovascular diseases, such as heart failure, acute myocardial infarction (MI), and cardiac arrhythmias. However, there are diurnal variations in the cardioprotective effects of the subgroups as a result of their different pharmacokinetic, pharmacodynamic, and pharmacogenetic profiles. We aimed to compare metoprolol and bisoprolol in terms of electrocardiogram (ECG) outcomes. A retrospective cross-sectional study was conducted at Prince Sultan Cardiac Center. The trial included 404 patients who met the inclusion criteria (204 in the metoprolol arm and 200 in the bisoprolol arm). Using case record forms that had already been created, information, such as patient demographics, medical histories, and treatment histories, was taken from their medical files. The most recent ECG records were also gathered. The ethical approval for this study was obtained from Qassim ethical committee (approval number: 45-44-902). There was no significant difference found between the patients in both arms in terms of baseline characteristics, age, or sex. In this retrospective cross-sectional study, we have compared the effects of metoprolol and bisoprolol beta blockers on ECG changes. The findings have indicated no difference between metoprolol and bisoprolol groups in terms of all ECG readings, particularly PR/ms, QTC-ms, and ventricular rate. Further studies are required to confirm these findings.

The influence of light on Interleukin-10: A preliminary study

Light influences circadian rhythms, including that of the stress hormone cortisol. Cortisol, in turn, has been observed to promote expression of the anti-inflammatory cytokine IL-10. It is thus of interest whether the cytokine IL-10 is also influenced by light, perhaps in accord with the diurnal variations in cortisol. Hence, this highly standardized preliminary sleep laboratory study in healthy adult men investigated a potential influence of different light exposure on IL-10 and cortisol concentrations in blood. In a between-subject design, N = 42 participants were exposed to either bright, dim, blue or red light after wake-up. Two mixed-model analyses with the factors of light condition and time (across eight IL-10 and cortisol sampling points) were conducted. Additionally, area under the curve measurements (AUCg and AUCi) were calculated for both cortisol and IL-10. Across all conditions, IL-10 and cortisol concentrations significantly changed over time. However, none of the light conditions exerted a greater influence on IL-10 or cortisol levels than others. For cortisol, there was greater total output (AUCg) in the blue-light condition in particular. Further research is needed to gain insight into whether or not types of light or cortisol levels have a hand in influencing natural IL-10 concentrations.

Diurnal Changes in Cloud Cover in Eastern Gabon and Their Impacts on Energy Balance, Light Availability, and Water Demand: A Case Study of the 2022 Dry Season

Abstract Western central Africa is atypical of the equatorial domain as the main dry season is cloudier than the rainy seasons. To understand this cloud cover’s diurnal evolution, we set up an infrared camera and acquired measurements of the total cloud cover fraction (TCF) and cloud optical depth at Bambidie, Gabon (0°44′30.5″S, 12°58′12.4″E), from May to October 2022. Diurnal variations in TCF can be summarized into four types, mostly discretized through the timing and duration of clouds clearing in the afternoon [early afternoon clearing (EaC), late afternoon clearing (LaC), and clear night (CNi)], while one type [no clearing (NoC)] shows overcast conditions all day long. Meteorological measurements show that NoC days record 50 W m−2 less shortwave incoming surface radiation, resulting in daytime temperatures 1°C lower than the seasonal norm, but 20% more diffuse light and 0.5 mm day−1 less ETo. Conversely, EaC days record 50 W m−2 more shortwave incoming surface radiation, leading to temperatures 1.5°C higher than the seasonal norm, but 40% more direct light. The larger water demand (0.5 mm day−1 more ETo) is partly compensated by more frequent rainfall at nighttime. The satellite estimates of Satellite Application Facilities for supporting Nowcasting and very short-range Forecasting (SAFNWC) capture the TCF variations for most of the four types well. They confirm that TCF is dominated by very low and low clouds whose dissipation in the afternoon and evolution into fractional and cumuliform convective clouds explains the clearings on EaC and LaC days. Satellite estimates also show that the four types of days extracted at Bambidie are representative of a larger-scale cloud cover evolution in western central Africa, with a west–east gradient in the timing of afternoon cloud dissipation.

Icelandic glacial dissolved organic carbon fluxes, composition and variability - relevance for the global glacial carbon budget

Despite their relatively large size, organic carbon (OC) fluxes from Icelandic glaciers have not been explicitly considered in current global glacial OC flux calculations. Most global glacial OC estimates are based on limited individual flux estimates, which show considerable spatial differences, are often based on melt season fluxes, and rarely account for seasonal and diurnal variability of glacial dissolved organic matter (DOM). Using an annual dataset of 25 Icelandic glaciers (and their glacial streams) we investigate DOM concentration and composition, calculating an estimate for downstream OC fluxes from Icelandic glaciers, considering diurnal and seasonal variability. DOM source and composition distinctly changed from a terrestrial character toward a more proteinaceous character as melt increased, both on a seasonal and diurnal basis, likely reflecting the flow path of the meltwater. While DOC concentration did not change on a diurnal basis, DOM composition was more labile in the afternoons, possibly indicating photochemical or biological transformation processes. Overall, the glacial streams predominantly acted as CO2 sinks. However, higher DOC concentrations, along with contributions of more proteinaceous DOM in proglacial streams, led to a decrease in the uptake potential for CO2. Finally, we estimated an export flux of 0.0026 ± 0.0029 Gg C yr−1 km−2 of DOC, and 0.011 ± 0.007 Tg C yr−1 km−2 of POC, from Icelandic glaciers. We reveal larger than previously assumed DOC and POC fluxes from Icelandic glaciers, with higher-than-global-average areal fluxes (~3 % and 9 % of global glacial C flux respectively). Our findings underscore the importance of revising current global estimates to include the not-fully-accounted-for contribution of Icelandic, and other glaciers. This is particularly important considering ongoing climatic changes will likely affect glacial meltwater discharge and sources, leading to altered DOM composition and DOC concentration, having potentially considerable consequences for glacial OC export and CO2 uptake potentials of glacial streams.

Observational evidence of impact of heavy rainfall events on surface energetics and soil variables over a tropical station Tirupati

Two back-to-back heavy rainfall events (HREs) produced enormous rainfall over a pilgrim city, Tirupati, located in the southern peninsular India, during 10–12 November 2021 (149.2 mm) and 17–19 November 2021 (234.2 mm). Surface measurements at Yerpedu, Tirupati (13.74°, 79.60°E) showed a drop of 2–3 °C in temperature and 8 hPa in pressure during HREs, indicating that these HREs were associated with two landfalling tropical depressions from the Bay of Bengal. The sporadic HREs in the past three decades caused floods over Tirupati and devastated landslides in the sacred Tirumala hills especially during the second HRE. Fundamental understanding of diurnal cycle of surface radiation is critical to model the climate. The effect of HREs on the surface essential climate variables at diurnal scale indicate a reduction in peak solar and net radiations by 500 W m−2 (> 62.5 %). Similar to observations, ERA5 reanalysis also indicates a significant reduction in net surface solar and thermal radiations, which are nearly equal in terms of % but vary in magnitude. Net solar and thermal radiations show dominant diurnal cycles with a reduced (66.7 % and 74.4 % respectively) diurnal amplitudes from no-rain to HREs. Soil moisture drydown curves at 5- and 10-cm depths shows 3 h long e-folding decay time for HREs, indicating an enhanced soil moisture memory after HREs. The soil drying process takes longer time at 10 cm than at 5 cm depth. Soil temperatures are significantly low at 5 cm to 30 cm depths and less than the 50 cm depth with weak diurnal variation during the events. The reflectivity (Z)-rain rate (R) and shape (μ)-slope (Λ) relations show variations from HREs to normal rain events. Knowing the importance of land-atmospheric processes feedbacks in model predictions at diurnal scale, this study quantified the HREs impact on surface essential climate variables, especially the energy balance and soil variables.

Urban Morphology and Surface Urban Heat Island Relationship During Heat Waves: A Study of Milan and Lecce (Italy)

The urban heat island (UHI) effect, marked by higher temperatures in urban areas compared to rural ones, is a key indicator of human-driven environmental changes. This study aims to identify the key morphological parameters that primarily contribute to the development of surface urban heat island intensity (SUHII) and investigates the relationship between SUHII and urban morphology using land surface temperature (LST) data from the Sentinel-3 satellite. The research focuses on Milan and Lecce, analyzing how urban geometry affects SUHII. Factors such as building height, aspect ratio, sky visibility, and surface cover are examined using approximately 1000 satellite images from 2022 and 2023. The study highlights seasonal and diurnal variations in SUHII, with particular emphasis on HW periods. Through multicollinearity and multiple regression analyses, the study identifies the main morphological drivers influencing SUHII in the two cities, specifically the Impervious Surface Fraction (ISF) and Mean Building Height (HM). Milan consistently exhibits higher SUHII, particularly during HWs, while Lecce experiences a negative SUHII, especially during the summer, due to lower urban density, more vegetation, and the low soil moisture around the urban area. Both cities show positive SUHII values at night, which are slightly elevated during HWs. The heat wave analysis reveals the areas most susceptible to overheating, typically characterized by high urban density, with ISF and HM values in some cases above the 90th percentile (0.8 and 13.0 m, respectively) compared to the overall distribution, particularly for Milan. The research emphasizes the importance of urban morphology in influencing SUHII, suggesting that detailed morphological analysis is crucial for developing climate adaptation and urban planning strategies to reduce urban overheating and improve urban resilience to climate change.

Sex and the Clock: Exploring Sex Differences in Chronotype and Circadian Preferences Among Cognitively Healthy Older Adults.

This study aimed to compare objective circadian rest-activity-rhythm (RAR) measures with self-reported circadian behavior and morning-evening preference in cognitively healthy older men and women. A total of 129 participants (ages 65-90) completed the Horne & Ostberg Morning-Eveningness Questionnaire (MEQ) and the Circadian Type Inventory (CTI) to assess their morning-evening preference and circadian traits, including rigidity, vigor, languidness, and flexibility. These subjective measures were compared to objective actigraphy data from a sub-cohort of 70 individuals who wore actigraphy watches for 24 hours a day over a 7-day period. Rest-activity rhythm variables were derived from the actigraphy data and analyzed. The results revealed sex differences in circadian behavior. Languid and flexible men (higher CTI scores) had significantly higher depression scores (GDS, p = 0.045) and showed more evening preference (MEQ, p = 0.007) compared to their vigorous and rigid counterparts, while no significant differences were found in women. Actigraphy data showed that men had less stable (interdaily stability, IS, p = 0.030) and more fragmented (interdaily variability, IV, p = 0.001) circadian rhythms than women. A significant association was found between acrophase time and CTI-FR scores (β = -0.406, p < 0.001), with earlier acrophase times linked to more rigid circadian rhythms. Additionally, earlier acrophase times and morningness preference were associated with faster information processing speeds (IPS, p = 0.018). These findings suggest that circadian behaviors and their impact on mood and cognition are more pronounced in older men than women, highlighting the value of actigraphy in assessing circadian profiles and sex differences in aging.

Diurnal Variation Reveals the Characteristics and Influencing Factors of Cool Island Effects in Urban Blue-Green Spaces

Urban blue-green space cooling island effect (BGCI) is effective in improving the thermal comfort of residents. However, there is little knowledge regarding the diurnal variation of BGCIs and the influencing factors. Therefore, we selected Beijing as the study area and used ECOSTRESS LST data and the inflection–maximum perspective method to explore the diurnal variation of BGCIs. Additionally, we investigated diurnal variations in the relative influence of the characteristics of the blue-green space itself, as well as the surrounding 2D and 3D landscape metrics using boosted regression tree model. The results indicated that BGCIs displayed distinct diurnal patterns. BGCIs progressively increased from sunrise to midday, decreased thereafter to sunset, reached its peak around midday, and diminished to a relatively low level and constant intensity at night. BGCIs of water bodies exhibited a significantly higher intensity compared to vegetation during the day, particularly around midday, with a difference in mean cooling intensity (CI) of 1.06 °C and mean cooling distance (CD) of 63.27 m, while the differences were minimal at night with a difference in mean CI of 0.02 °C and mean CD of 9.64 m. The features of vegetation had a more significant impact on BGCIs during the day, particularly around midday (CI: 32.30% around midday and 13.86% at night), while the 3D metrics influenced BGCIs more at night (CI: 26.40% around midday and 35.81% at night). The features of water bodies had a greater impact during the midday (52.87% around midday and 10.46% at night), with the landscape metrics of surrounding water bodies playing a more important role at night (15.56% around midday and 38.28% at night). The effect of tree height, shape index of vegetation, and surrounding building coverage ratio of water bodies on BGCIs exhibited opposite trends around midday and at night. Optimizing the landscape surrounding blue-green spaces is more cost-effective than the blue-green spaces themselves for nighttime thermal comfort, especially in 3D urban landscapes. These findings emphasize the imperative and essentiality of exploring diurnal variations in BGCIs, providing valuable information for mitigating UHI effects.

The Characteristics, Sources, and Health Risks of Volatile Organic Compounds in an Industrial Area of Nanjing

This study investigates the chemical complexity and toxicity of volatile organic compounds (VOCs) emitted from national petrochemical industrial parks and their effects on air quality in an industrial area of Nanjing, China. Field measurements were conducted from 1 December 2022, to 17 April 2023, focusing on VOC concentrations and speciations, diurnal variations, ozone formation potential (OFP), source identification, and associated health risks. The results revealed an average total VOC (TVOC) concentration of 15.9 ± 12.9 ppb and an average OFP of 90.1 ± 109.5 μg m−3. Alkanes constituted the largest fraction of VOCs, accounting for 44.1%, while alkenes emerged as the primary contributors to OFP, comprising 52.8%. TVOC concentrations peaked before dawn, a pattern attributed to early morning industrial activities and nighttime heavy vehicle operations. During periods classified as clean, when ozone levels were below 160 μg m−3, both TVOC (15.9 ± 12.9 ppb) and OFP (90.4 ± 110.0 μg m−3) concentrations were higher than those during polluted hours. The analysis identified the key sources of VOC emissions, including automobile exhaust, oil and gas evaporation, and industrial discharges, with additional potential pollution sources identified in adjacent regions. Health risk assessments indicated that acrolein exceeded the non-carcinogenic risk threshold at specific times. Moreover, trichloromethane, 1,3-butadiene, 1,2-dichloroethane, and benzene were found to surpass the acceptable lifetime carcinogenic risk level (1 × 10−6) during certain periods. These findings highlight the urgent need for enhanced monitoring and regulatory measures aimed at mitigating VOC emissions and protecting public health in industrial areas. In the context of complex air pollution in urban industrial areas, policymakers should focus on controlling industrial and vehicle emissions, which can not only reduce secondary pollution, but also inhibit the harm of toxic substances on human health.

Diurnal Variations in Upper and Lower Body Power in Adolescent Volleyball Players: Exploring Time-of-Day Effects on Performance

Background/Objectives: This study aims to investigate the daily variations in upper and lower body power performance in adolescent volleyball players. Methods: The sample consisted of 50 young male volleyball players (14.12 ± 0.8 years), actively involved in regular training and competition. Players were tested for vertical jump tests and medicine ball throws twice, once in the morning (8:00–9:30 h) and once in the evening (18:00–19:30 h). Results: Significant differences (p &lt; 0.05; ES = 0.35–0.42) in vertical jump were observed when comparing the morning and evening performance except for counter movement jump with arm swing, where there were no significant differences (p = 0.21). The results for the upper body power tests revealed a significant difference only in the standing medicine ball throw (p = 0.05; ES = 0.35). There were no significant differences in lying and seated medicine ball throw (p &gt; 0.05). Conclusions: This study demonstrated that lower body power, manifested in vertical jump performance, was significantly better in the evening compared to the morning. For upper body assessments, the standing medicine ball throw appears more reflective of volleyball-specific movements, while the lying and sitting throw may be less applicable. These findings suggest that volleyball training and testing, especially for leg power, may be more effective later in the day, while upper body performance appears less affected by time.

Modulation of diurnal variation in rainfall associated with tropical cyclones over the East Asia–Western North Pacific region by environmental vertical wind shear

AbstractVertical wind shear (VWS), as an important dynamic factor influencing tropical cyclone rainfall (TCR), has a remarkable diurnal cycle of variation over the East Asia–western North Pacific region. The magnitude of tropical cyclone (TC)‐experienced VWS has enhanced amplitude but different phases over the South China Sea (SCS) and coastal East China (CEC) compared with that over the open ocean. Diurnal variation in TCR over the SCS shows statistically significant correlation with that of VWS. The convection concentrated in the downshear‐left quadrant strengthens markedly when VWS becomes large, thereby delaying the peak rainfall in the inner core of the TC and enhancing the amplitude of the diurnal cycle of TCR at ~09 local standard time. Over CEC, the diurnal signal of TCR is very weak but statistically significant in the downshear‐left and upshear‐right quadrants with opposite phase, illustrating the change in asymmetry of the spatial distribution of TCR induced by the large VWS diurnal cycle. The findings of this study could provide reference for improved forecasting of TCR on the fine temporal scale.

Seasonal Effects on Outdoor Stability of Perovskite Solar Cells

AbstractThe critical challenge for the commercialization of perovskite solar cells (PSCs) is their operational stability. PSCs’ outdoor operation exposes the cells to a combination of stress factors that are difficult to reproduce by indoor testing due to diurnal and seasonal variations. This highlights the need for outdoor testing under operational conditions. The effect of climate conditions on outdoor operational lifetime/ degradation of n‐i‐p PSCs is systematically studied herein. Their lifetime indicators are determined in different seasons, and correlated with the outdoor irradiance and temperatures measured simultaneously. Based on this outdoor measurement analysis and indoor light cycling stability tests, it is suggested that ambient temperatures induce a more significant effect than the irradiance on the PSC's lifetime/ degradation. The study also suggests different roles played by the temperatures during the diurnal light versus dark periods: the day/ light time maximum temperatures have a more significant effect on the long‐term degradation. In contrast, minimum temperatures during the night/ dark cycles significantly affected the diurnal reversible degradation and the initial fast degradation. The results show that the commonly used lifetime indicators T80 and T50 are climate‐dependent, and their use for comparative purposes is valid only if measured in similar climatic conditions.