Pattern Of Seasonal Variation Research Articles

Correlations Between Spatiotemporal Variations in Phytoplankton Community Structure and Physicochemical Parameters in the Seungchon and Juksan Weirs

The Yeongsan River is one of the four major rivers in South Korea. Since the construction of two weirs as part of the Four Major Rivers Project to secure water resources in 2011, issues with algal blooms have frequently arisen, prompting the Ministry of Environment of Korea to conduct continuous monitoring of water quality and algal outbreaks. This study, conducted between 2019 and 2023, examined the relationship between the phytoplankton community structure and physicochemical factors at the Seungchon and Juksan weirs. Phytoplankton were categorized into four groups (Bacillariophyceae, Chlorophyceae, Cyanophyceae, and other phytoplankton), and 20 dominant genera were selected for analysis. As microalgal species vary depending on environmental conditions, understanding the specific relationships among the microalgae observed in the study area can help explain their occurrence mechanisms and contribute to the development of effective management strategies. Therefore, we used principal component analysis (PCA) to analyze the seasonal variation patterns of the four microalgal groups and visualize key data features through dimensionality reduction. Additionally, PCA was employed to identify and visualize environmental factors related to seasonal variations in phytoplankton communities. PCA helped elucidate how different environmental factors influence phytoplankton fluctuations across seasons. We used canonical correspondence analysis (CCA) to investigate the relationships among the 20 dominant genera in each group and environmental factors. Additionally, CCA was used to analyze the relationship between the distribution of the top five dominant phytoplankton taxa in each group and various environmental factors. CCA allowed for a detailed examination of how these dominant taxa interact with environmental conditions. PCA revealed significant correlations between other phytoplankton and Chl-a in spring and Cyanophyceae and water temperature in summer. Bacillariophyceae was positively correlated with nitrogen-based nutrients but negatively with phosphate phosphorus (PO4-P). CCA revealed significant correlations between dominant genera and environmental factors. Stephanodiscus sp. was associated with nitrogen-based nutrients, whereas Microcystis sp. and Dolichospermum sp. were associated with water temperature and PO4-P. Stephanodiscus sp. affected water treatment through filtration and sedimentation issues, whereas Microcystis sp. and Dolichospermum sp. produced the toxin microcystin. These findings offer valuable insights for water quality management.

Strength degradation characteristics and damage constitutive model of sandstone under freeze-thaw cycles.

Thorough investigation into the laws governing frozen rock damage in high-altitude and cold regions can offer valuable insights for advancing infrastructure construction, ecological environment protection, and sustainable development on the Qinghai-Xizang Plateau. This study combined with the seasonal variation patterns of frozen rocks in the Qinghai-Xizang Plateau, and processed the rock samples using a freeze-thaw interval of -20 °C~20 °C. Uniaxial compression test was conducted based on the MTS816 rock mechanics testing system. The porosity changes of rock samples with different freeze-thaw cycles were analyzed using the MesoMR12-060H-I nuclear magnetic response analysis system. A rock freeze-thaw load coupled damage constitutive model was derived using the Lemaitre equivalent strain theory. Research has shown that during the freezing process, the pore water inside the rock sample is affected by the phase change of water-ice, resulting in frost heave force, which further promotes the expansion of the pore walls and the initiation of new cracks. When melted, pore water migrates towards newly formed micropores, thereby affecting the changes in the pores of rock samples. The increase in porosity at the micro level weakens the mechanical parameters of rocks at the macro level. The segmented freeze-thaw damage constitutive model based on Lemaitre equivalent strain theory can well fit the experimental results involved in this study, as well as the experimental results obtained by other researchers. The compaction stage can partially reflect the changes in sandstone pore structure under freeze-thaw cycles.

Seasonal variations in haematological and biochemical parameters of healthy Gambian adults: Retrospective study 2018-2022.

The objectives of this study were to determine the presence and effect of seasonal variations and provide insights into trend from 2018 to 2022 in a comprehensive set of routine haematological indices and biochemical measurements in Gambian adults with no known underlying health condition. We retrieved five years of data from an electronic database and analysed 493 full blood counts and 643 biochemical data from different individuals. In this study, we focused on data from individuals with no known underlying health condition who visited the clinical diagnostic laboratory for routine medical examinations or assessments.Our study found a positive association between seasonality (wet season as the reference) and Hb (HB: 0.014(0.015), P<0.05), White blood cells (WBC) (WBC: 0.243(0.163), p = 0.0014), and neutrophils (neutrophils: 0.271(0.131), P<0.05) with exception to red blood cells (RBC) (RBC: - 0.184(0.061), P< 0.003) that showed negative association. Despite the association, the seasonal effects on our derived reference intervals for haematological indices and biochemical measurements from wet season to dry season were not statistically significant (P>0.05). In addition, we observed in our heatmap result that some laboratory parameters, including HB, RBC, haematocrit (HCT), urea, liver enzymes, and potassium, showed seasonal variation patterns throughout the year, with median levels being normal to slightly low during the dry season and normal to high during the wet season. We also found no significant difference (P>0.05) among the median values for all parameters from 2018 to 2022. Additionally, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) parameters showed a consistent declining trend from 2018 to 2022. Our study found no seasonal effects on the derived reference intervals of haematological indices and biochemical measurements. However, we observed changes in patterns for certain parameters particularly HB, RBC, liver enzymes, and potassium based on seasonality.

Heavy metals seasonal variation and uptake pattern in rice grown in Kano State, Nigeria

Heavy metals seasonal variation and uptake pattern in rice grown in Kano State, Nigeria

Integrated Morphological, Comparative Transcriptomic, and Metabolomic Analyses Reveal Mechanisms Underlying Seasonal Patterns of Variation in Spines of the Giant Spiny Frog (Quasipaa spinosa).

Quasipaa spinosa, commonly known as the spiny frog, is an economically valued amphibian in China prized for its tender meat and nutritional value. This species exhibits marked sexual dimorphism, most notably the prominent spiny structures on males that are pivotal for mating success and species identification. The spines of Q. spinosa exhibit strong seasonal variation, changing significantly with the reproductive cycle, which typically spans from April to October. Sexually mature males develop densely packed, irregularly arranged round papillae with black spines on their chests during the breeding season, which may then reduce or disappear afterward, while females have smooth chest skin. Despite their ecological importance, the developmental mechanisms and biological functions of these spines have been inadequately explored. This study integrates morphological, transcriptomic, and metabolomic analyses to elucidate the mechanisms underlying the seasonal variation in spine characteristics of Q. spinosa. Our results demonstrate that spine density inversely correlates with body size and that spine development is accompanied by significant changes in epidermal thickness and keratinization during the breeding season. Comparative transcriptomic analysis across different breeding stages revealed significant gene expression alterations in pathways related to extracellular matrix interactions, tyrosine metabolism, Wnt signaling, and melanogenesis. Metabolomic analysis further identified significant seasonal shifts in metabolites essential for energy metabolism and melanin synthesis, including notable increases in citric acid and β-alanine. These molecular changes are consistent with the observed morphological adaptations, suggesting a complex regulatory mechanism supporting spine development and functionality. This study provides novel insights into the molecular basis of spine morphogenesis and its seasonal dynamics in Q. spinosa, contributing valuable information for the species' conservation and aquaculture.

Spatiotemporal variations of domoic acid: New findings in the sedimentary environment of a typical nearshore mariculture bay, China

Domoic acid (DA) is a neurotoxin produced by marine microalgae. It tends to accumulate in marine shellfish and fish, posing a threat to aquaculture and seafood consumers’ health. In this study, DA in the surface and bottom seawater, sediment, and porewater of the Jiaozhou Bay, a typical mariculture bay in China, was systematically investigated for the first time over different seasons. Surprisingly, a high concentration of DA was discovered in the marine sediment porewater (maximum detected concentration: 289.49 ng/L) for the first time. DA was found to be extensively distributed in the water body and sedimentary environment of the Jiaozhou Bay. DA in the surface and bottom seawater of Jiaozhou Bay in spring was uniformly distributed, whereas DA showed obvious spatial variations in summer and winter. The high concentration areas of DA are located in the north of Jiaozhou Bay and decreased to the south areas. DA was also distributed in the sediment (spring mean: 316.57 ng/kg; summer mean: 10.22 ng/kg; winter mean: 237.08 ng/kg) and porewater (spring mean: 129.70 ng/L; summer mean: 53.54 ng/L; winter mean: 19.90 ng/L) of Jiaozhou Bay. The DA concentrations in the surface sediment and porewater were higher in the spring than in the winter and summer, contrary to the seasonal variation pattern observed in the surface and bottom seawater. The DA concentration in porewater was significantly higher than in the surface and bottom seawater, indicating that the risk of pollution contamination from DA to benthic fishery organisms may be underestimated. Overall, DA is widely distributed in the seawater and also in the benthic environment of Jiaozhou Bay and exhibited potential harm to fishery organisms varied greatly with seasons. It is an important discovery for marine algae toxins and has important guiding significance and important indicative role for the routine monitoring and management of DA pollution in water and benthic environment.

Matching Satellite Sun-Induced Chlorophyll Fluorescence to Flux Footprints Improves Its Relationship with Gross Primary Productivity

Sun-induced chlorophyll fluorescence (SIF) holds enormous potential for accurately estimating terrestrial gross primary productivity (GPP). However, current studies often overlook the spatial representativeness of satellite SIF and GPP observations. This research downscaled TROPOMI SIF (TROPOSIF) and its enhanced product (eSIF) in China’s Saihanba Forest Region to obtain high-resolution SIF data. SIF was simulated using the SCOPE model, and the downscaled SIF’s reliability was validated at two forest eddy covariance (EC) sites (SHB1 and SHB2) in the study area. Subsequently, the downscaled SIF data were matched to the EC footprint of the two forest sites, and the relationship between SIF and GPP was compared at various observational scales. Additionally, the ability of downscaled TROPOSIF and eSIF to track GPP was compared, along with the correlations among several vegetation indices (VIs) and GPP. The findings reveal the following: (1) Downscaled TROPOSIF and eSIF showed a strong linear relationship with SCOPE-modeled SIF (R2 ≥ 0.86). The eSIF closely matched the SCOPE simulation (RMSE: 0.06 mw m−2 nm−1 sr−1) and displayed a more consistent seasonal variation pattern with GPP. (2) Comparisons among coarse-resolution SIF, EC footprint-averaged SIF (SIFECA), and EC footprint-weighted SIF (SIFECW) demonstrated significant improvements in the linear relationship between downscaled SIF and GPP (the R2 increased from the range of 0.47–0.65 to 0.78–0.85). SIFECW exhibited the strongest relationship with GPP, indicating that matching SIF to flux footprints improves their relationship. (3) As the distance from the flux tower increased, the relationship between SIF and GPP weakened, reaching its lowest point beyond 1 km from the tower. Moreover, in the highly heterogeneous landscape of the SHB2 site, the relationship between VIs and GPP was poor, with no clear pattern as distance from the flux tower increased. In conclusion, the strong spatial dependency of SIF and tower-based GPP emphasizes the importance of using high-resolution SIF to accurately quantify their relationship.

A national-scale assessment on the spatial and temporal variations in water color for urban lakes in China

Monitoring the variations of lake water quality is essential for urban water security and sustainable eco-environment health. However, it is challenging to investigate the water quality of urban lakes at large scales due to the need for large-amount in situ data with diverse optical properties for developing the remote sensing inversion algorithms. Forel-Ule Index (FUI), a proxy of quantifying water color, whose calculation does not require in situ data of specific properties, can comprehensively reflect water quality conditions. However, the spatial and temporal distribution of water color in Chinese urban lakes is still poorly understood. To fill this research gap, this study investigated the spatial distribution of water color in 523 urban lakes (area > 0.5 km2) in China using the FUI derived from the high-quality Multi-Spectral Instrument (MSI) data onboard Sentinel-2 during the ice-free period (April–October) from 2019 to 2022. The monthly and seasonal variation patterns of water color in urban lakes were also analyzed. Our results show that green domain is the most common color of urban lakes, with about 86 % of urban lakes in China being green, and non-green lakes accounting for only 14 % of the total number of lakes. The monthly variation of FUI in urban lakes across the country and multiple geographic regions is basically the same. The monthly average FUI first increases, then decreases, and then rebounds. We also found that the seasonal variation of water color in most urban lakes in southern and northern China is opposite. This study helps to comprehensively understand the spatial and temporal variation of water color and quality of urban lakes in China, providing key basic information for the protection and governance of urban lakes.

Seasonal Variation and Antibiotic Susceptibility Patterns of Bacteriological Parameters in Groundwater Sources in Oyi LGA, Anambra State, Nigeria

Potable water is essential for health and survival of all life forms. Contamination of groundwater sources by microbes, organic and inorganic matter has continued to negatively affect the well-being of most people in developing countries such as Nigeria. Thus, this study aimed to determine the seasonal variation and antibiotic susceptibility patterns of bacteriological parameters in groundwater sources in Oyi LGA, Anambra State, Nigeria. Hand-dug well and borehole water sites were randomly selected in five communities of Oyi LGA, and water samples were aseptically collected and analyzed using standard microbiological procedures. The total heterotrophic counts of bacteria isolated from groundwater samples during both seasons were between 1.3×102 and 2.87×104 CFU/mL, total coliform counts ranged from 2 to 165 MPN/100mL and faecal coliform ranged from 0 to 32 MPN/100mL. Probable bacterial isolates in groundwater samples were Escherichia coli, Klebsiella aerogenes, Shigella flexneri, Enterococcus faecalis and Enterobacter sp. Seasonal variations showed there were more bacterial loads in sampled water during wet season than dry season. Antibiotic susceptibility test revealed that all the bacterial isolates were sensitive to Levofloxacin and Ofloxacin, and are recommended for treatment of diseases caused by some of these pathogens. Shigella flexneri exhibited highest susceptibility (60%) to the antibiotics, while Enterobacter faecalis showed highest resistance (70%). Escherichia coli exhibited 50% susceptibility and 50% resistance. The sampled water sources did not meet the WHO and NSDWQ guidelines for drinking water, and therefore not fit for human consumption without adequate treatment.

Seasonal Variation and Distribution Patterns of Endophytic Community in Withania somnifera

Withania somnifera also known as Ashwagandha used as rasayana (tonic) in Ayurvedic system of medicine. It is widely considered as Indian Ginseng and possesses medicinal properties like adaptogenic, antistress, anxiolytic, anti-arthritic, anti-inflammatory etc. There is long history of microbes having stable symbiotic relationship with plants aiding them in growth and survival. This endophytic relationship is also been observed in medicinal plants. This study is an attempt to observe the biodiversity of endophytic fungal community in Withania somnifera and to understand their colonization. The study was aimed to isolate endophytes from different organs of Withania somnifera with seasonal variations. A total of 131 endophytic fungi were isolated from 450 explants from different organs like leaves, stems and roots of W. somnifera. The overall colonization rate of endophytes in winter, summer and monsoon were 42.67%, 7.33% and 37.33% respectively. Among the identified isolates, most abundant and frequently isolated genera were Alternaria, Fusarium and Chaetomium sps. The dominant species isolated in winter were the Fusarium moniliformae and Chaetomium globosum from leaves with 17.24% and 13.79% dominant frequency, respectively. While Alternaria raphani and Chaetomium globosum were most dominant species in summer from leaves with 40% dominant density. In the monsoon, Microsporum ferruginem was the most dominant species isolated from leaves and stem with 61.29% and 42.86%, respectively. The most recurring endophytic species of Ascomycetes group were Alternaria alternata and Chaetomium globosum seen in all seasons.

Exploring ionospheric plasma density trends in the Indian equatorial crest region under varying solar activity conditions

Long-term trends in the evolution of ionospheric plasma at Hyderabad (17.38∘N, 78.48∘E; 8.52∘N Magnetic Latitude), a near-equatorial anomaly (EIA) crest region of the Indian ionospheric sector, have been studied using 9 years of vertical Total Electron Content (TEC) data from 2004 to 2009 and 2011 to 2013 using global positioning satellites (GPS) measurements. The study examined the mean diurnal, monthly, seasonal, and yearly variations of TEC during geomagnetic quiet days in different seasons from 2004 to 2013. The findings reveal that the daytime TEC at the anomaly crest region exhibits semi-annual variations throughout the study period, while midnight TEC shows semi-annual variation only during the high solar activity years of 2011–2013. The winter anomaly was observed in 2004 and 2006. The study also assessed the performance of the International Reference Ionosphere (IRI) 2016 model in reproducing GPS TEC variability at the equatorial crest region. The diurnal and seasonal variation patterns in IRI-TEC show a good correlation with GPS TEC. However, the IRI 2016 model tends to overestimate TEC values during low solar activity conditions (2006–2009) but represents TEC variations reasonably well during high solar activity periods (2011–2013). Nevertheless, the IRI model fails to capture the wide plateau-like structure in the peak TEC, typically occurring between 1200–1600 IST at Hyderabad. Additionally, IRI-TEC consistently indicates very low TEC values during the early morning hours, whereas GPS-TEC measurements suggest a significant presence of plasma density. The study suggests a strong influence of the solar cycle on TEC variations at Hyderabad, evident from the positive correlation (R2= 0.71) with the F10.7 cm index. This characteristic is also well represented by the IRI 2016 model.

Seasonal changes of Chlorophyll-A concentration in Jiujiang city based on remote sensing

Abstract. The Chlorophyll-a (Chla) concentration is an important parameter characterizing the water quality of rivers and lakes. Satellite remote sensing provides new opportunities for the quantitative monitoring of Chla concentration in large-scale water bodies. In this study, Sentinel-2 satellite remote sensing data integrated on the Google Earth Engine (GEE) remote sensing big data platform are employed, along with hourly measured water quality site data, to establish a quantitative inversion model for Chla concentration water quality parameters in Jiujiang City within Jiangxi Province, China. The Chla concentration is estimated for each quarter from 2020 to 2022, and the spatial distribution is analyzed, revealing the changing trend of Chla concentration over the past three years. The key findings are as follows: (1) The quantitative inversion model for Chla concentration has been validated with measured data, achieving a model accuracy of 0.53; (2) The spatial inversion results of Chla concentration exhibit an increasing trend that is consistent with actual measurement site results; (3) Owing to the influence of human activities and the peak-low water level of rivers and lakes, Chla concentration shows a discernible seasonal variation pattern. This methodology offers a new perspective for analyzing the seasonal variation characteristics of Chla concentration in rivers and lakes, providing valuable insights for the sustainable management of river and lake water quality.

Seasonal variation and uptake pattern of heavy metals in maize

The detrimental impact of heavy metals on human health necessitates a focus on their contamination in the food chain. Heavy metals possess carcinogenic, mutagenic, teratogenic, and endocrine-disrupting properties. The objective of the study was to ascertain how Zn, Pb, Cd, Ni, Co, Cu, Cr, and Hg are accumulated in the roots and grains of maize samples cultivated under the Kano River Irrigation Project during both wet and dry seasons production and subsequently compare the levels of these heavy metals with the recommended permissible limits established by FAO/WHO. Additionally, the research sought to employ Translocation Factors to examine the uptake pattern of heavy metals in maize during the two growing seasons. Maize samples were procured from 10 different locations within the irrigation scheme during 2022 wet season and 2023 dry season harvests. The samples were prepared using standard laboratory protocols and heavy metals were determined using atomic absorption spectrophotometer. The heavy metals accumulation in maize grains was found in the order Zn&gt;Cu&gt;Pb&gt;Ni&gt;Co during wet season production. Cd, Cr, and Hg were not detected in samples collected during the wet season. It is only the concentration of Zn that exceeded the permissible limit in the samples collected during wet season production. The accumulation order during the dry season was Zn&gt;Cu&gt;Cr&gt;Pb&gt;Ni&gt;Co&gt;Cd. Hg was not detected in all the maize grain samples. The concentrations of Zn, Pb, Cd and Cr exceeded permissible limits in maize grains samples collected during dry season production.

Observation of thunderstorm-induced muon events in GRAPES-3 experiment

The GRAPES-3 tracking muon telescope located at Ooty (India) records short-term variations in the muon intensity during major thunderstorms, termed thunderstorm-induced muon events (TIMEs). Its excellent angular resolution, coupled with high statistics, allows us to observe subtle directional variations in muon rate. We detected 169 statistically significant events during the five-year period from 2006 through 2010. The monthly and seasonal variation patterns of the observed TIMEs were discussed, emphasizing their occurrence and climatological aspects. The annual diurnal pattern was plotted with the Carnegie curve, considering their possible causal link with the global electric circuit. The work represents the first report from any experiment for such an extended period in an uninterrupted manner.

Acute conjunctivitis – antibiotic susceptibility and resistance to different antibiotics in main Eye Hospital, Tripoli, Libya

Acute conjunctivitis is characterized by inflammation of the conjunctiva of less than 3 to 4 weeks duration, cellular infiltration, and exudation. It may also result in corneal, lid, or orbital involvement which may lead to various complications. Bacterial conjunctivitis is a self-limiting process, but topical antibiotic treatment is recommended to eradicate the pathogen and reduce symptom duration. A hospital-based prospective study was conducted in the emergency and casualty department in Zawyat Aldahmani Eye Hospital, Tripoli /Libya comprising out-patients (OPD) visiting the department from June to December 2019 (186 cases). The primary objective was to evaluate the bacteriological pattern and the secondary objectives were to evaluate seasonal variation and antibiotic sensitivity pattern of the isolates. Conjunctival swabs included patients from both sexes (males n_106 and females n_80) and different ages; 80.1% of adults of the whole studied cases and the rest were children under 12 years old. Staph. hominis (26.17%) was the predominant organism isolated throughout the study. The commonest single organism isolates were Staph. haemolyticus (11.21%) Staph. aureus (9.35%). All isolates were identified and susceptibility patterns towards about 34 different antibiotics were studied. There were 186 patients enrolled. Of all cultures, 57.5% (107) yielded one of the study pathogens. Gram-positive organisms were isolated from 83 (77.57%) of cultures, gram-negative organisms were isolated from 15 (14.02%), and 9 (8.4%) were fungal growth. From 107 gram-positive isolates, 19 samples (22.9%) gave coagulase-positive results and 64 samples (77.1%) gave negative results. All the major organisms (S. aureus, S. hominis, S. hemolytic, S. epidermidis, E. coli, Mycobacterium, and Moraxilla catarrhalis) susceptible to cephalosporins, macrolides, aminoglycosides and fluoroquinolones (levofloxacin). Tetracycline has the lowest effect on both gram-positive and gram-negative isolates. In conclusion, our findings should alert physicians on the choice of appropriate antibiotic treatment after applying AST to the identified strains and on the potential role of conjunctivitis in the spread of antibiotic-resistant pathogens. In addition, external bacterial infections of the eye were most frequently caused by the common skin bacteria. Staphylococci spp. was by far the most common bacterial pathogen.

Responses of underground air and drip water geochemistry to meteorological factors: A multi-parameter approach in the Rull Cave (Spain)

Our research aims to assess the complex interactions between the elements that constitute and influence a cave system through the analysis of an extensive dataset of climatic and environmental parameters (222Rn, CO2, drip rates, chemical composition, and environmental isotopes) measured in air, water, and solid in the Rull Cave (southeastern Spain). Of particular importance is understanding the effect of rainfall and temperature on water and gas transport through the epikarst and the involved processes. Our results show that the cave gaseous concentration patterns do not only depend on the temperature-caused movement of air masses, but they can also be affected by abundant rainfall. The δ18O and δD composition of cave water also relies on such precipitations for the effective transfer of the rainfall signal into the cave, which can take between 3 and 7 days. The elemental ratios (Sr/Ca and Mg/Ca) show high responsiveness to the water drip rate, hinting that enhanced prior calcite precipitation (PCP) occurs at slower drip rates. Despite this, and regardless of drip rates, calcite saturation indices follow a seasonal variation pattern inversely proportional to the cave air CO2 concentration, while δ13C-DIC is proportional. Our results show how the interlinkage between these multiple components defines the dynamics of the atmosphere-soil-cave system. Cave monitoring is then essential to understand the karstic vadose zone, which is highly sensitive to climatic influence and its changes.

Characteristics and Source Analysis of Carbonaceous Aerosols in PM2.5 in Huaxi District, Guiyang

Carbonaceous aerosol, as an important component of atmospheric aerosol, has a significant impact on atmospheric environmental quality, human health, and global climate change. To investigate the characteristics and sources of carbonaceous aerosol in atmospheric fine particulate matter (PM2.5) in Huaxi District of Guiyang, an in-situ observational study was conducted during different seasons in 2020, and the carbonaceous components of PM2.5 were measured using a thermal-optical carbon analyzer (DRI Model 2015). The results of the study showed that the average concentrations of PM2.5, total carbonaceous aerosol (TCA), organic carbon (OC), secondary organic carbon (SOC), and elemental carbon (EC) concentrations during the observation period were (39.7±22.3), (14.1±7.2), (7.6±3.9), (4.4±2.6), and (2.0±1.0) μg·m-3, respectively, and the mean value of OC/EC was (3.9±0.8). ρ(PM2.5), ρ(TCA), ρ(OC), ρ(SOC), and ρ(EC) showed a seasonal variation pattern with the highest in winter [(52.6±28.6), (17.0±9.6), (9.1±5.2), (6.1±3.9), and (2.4±1.2) μg·m-3, respectively] and the lowest in summer [(25.1±7.1), (11.6±3.6), (6.3±1.9), (3.7±1.2), and (1.6±0.6) μg·m-3, respectively]. The seasonal variation in OC/EC showed summer (4.2±0.8) > winter (3.8±0.9) > autumn (3.8±0.5) > spring (3.7±0.9), indicating the presence of SOC generation in all seasons in Huaxi District. SOC showed a significant correlation with OC (R2 =0.9), and the SOC concentration tended to increase with the increase in atmospheric oxidation. OC showed a good correlation with EC in all seasons, with the highest in autumn (R2 =0.9) and lower correlations in the other three seasons (R2 ranged from 0.74 to 0.75), indicating a common source. According to OC/EC ratio range, it was preliminarily determined that carbonaceous aerosol came from vehicle exhaust emissions, coal burning emissions, and biomass combustion emissions. In order to further quantify the contribution of major emission sources to carbonaceous aerosol, the results of this study using PMF to analyze the sources of carbonaceous aerosol showed that the main sources of carbonaceous aerosol in Huaxi District of Guiyang were coal combustion sources (29.3%), motor vehicle emission sources (21.5%), and biomass combustion sources (49.2%).

Effects of Sea Land Breeze on Air‐Sea Turbulent Heat Fluxes in Different Seasons Using Platform Observation in East China Sea

AbstractUsing 2‐year platform observations, this study investigates seasonal characteristics of sea land breeze (SLB) and how it influences air‐sea turbulent heat fluxes (THFs) in the coastal areas of East China Sea (ECS) in different seasons. Unlike other SLB studies, this study uses hourly observation on a sea platform to explore SLB's effect on both air‐sea latent heat and sensible heat transferring. The results show that sea wind (SW) does not have an obvious seasonal variation pattern while land wind (LW) is stronger in autumn and winter. The SLB day number shows a clear seasonal variation pattern, which accounts for 38.04% and 18.23% of summertime and wintertime days, reaching its peak and bottom respectively. The latent heat flux (LHF) and sensible heat flux (SHF) are high in autumn and winter while low in summer. The SLB‐contributed LHF and SHF reach peaks in autumn and winter, which are 61.07 and 7.39 W/m2 respectively. The contribution importance of SLB on air‐sea sensible/latent heat transferring is highest in summer while lowest in winter. On SLB days, the SHF decreases significantly by at least about 50% while LHF decreases moderately in all seasons, among which spring witnesses an inversion of sensible heat transferring direction. The warming effect of SLB is mainly responsible for the slump of SHF on SLB days. Multiple factors including relative humidity (RH), background wind field and in situ radiation cause the LHF decrease together, whose changing range varies with season.

Evaluating groundwater resources trends through multiple conceptual models and GRACE satellite data.

In this research, three numerical groundwater flow models, developed and calibrated from three equally plausible conceptual models over the Nasia Basin, have been used to assess groundwater resources variations over a transient period. The use of multiple numerical models reduces the effect of uncertainties in conceptual model formulation. All the three calibrated numerical models indicate an increasing trend of groundwater recharge and storage over the period of the groundwater level monitoring. This suggests that the prevailing erratic climatic conditions in the area are conducive for increasing groundwater recharge and storage in the terrain. The high-intensity, short duration rainfall patterns, attending climate change in the basin, enhance high levels of infiltration and percolation, leading to steadily increasing groundwater recharge. Groundwater recharge estimates from each of the models over the transient period appear to reflect the pattern of seasonal variations in rainfall in the region. Data from the models indicates a significant role of baseflow in sustaining perennial streamflow in the area. This presents a significant development in terms of groundwater-based adaptation projects, especially in agriculture. The trend of groundwater recharge in the Nasia Basin is in sync with regional groundwater storage variations estimated from the Gravity Recovery and Climate Experiment (GRACE) satellite data collected and processed over the Volta Basin. At the Volta Basin level, groundwater storage variations indicate a strong positive trend of increasing groundwater recharge from 2002 (beginning of the GRACE mission) to 2022 (end point of the data used for this research). Analysis of the GRACE data suggests that there is a cumulative increase in groundwater storage by 30cm, representing approximately 120 km3 of groundwater over the period in the basin. This translates into approximately 15mm/year of groundwater storage increase. Thus, at both the regional and local levels, groundwater appears to be responding positively to the impacts of erratic rainfall patterns observed in the area recently. The high-intensity, short duration rainfall patterns appear to favor significant groundwater recharge, resulting in a strong positive groundwater storage signal. The high positive groundwater storage signal suggests increasing groundwater resources potential in the area, indicating promising opportunities for groundwater-based climate change adaptation interventions.

Patterns in acute aortic dissection and a connection to meteorological conditions in Germany.

Acute type A aortic dissection (ATAAD) is a dramatic emergency exhibiting a mortality of 50% within the first 48 hours if not operated. This study found an absolute value of cosine-like seasonal variation pattern for Germany with significantly fewer ATAAD events (Wilcoxon test) for the warm months of June, July, and August from 2005 to 2015. Many studies suspect a connection between ATAAD events and weather conditions. Using ERA5 reanalysis data and an objective weather type classification in a contingency table approach showed that for Germany, significantly more ATAAD events occurred during lower temperatures (by about 4.8 K), lower water vapor pressure (by about 2.6 hPa), and prevailing wind patterns from the northeast. In addition, we used data from a classification scheme for human-biometeorological weather conditions which was not used before in ATAAD studies. For the German region of Berlin and Brandenburg, for 2006 to 2019, the proportion of days with ATAAD events during weather conditions favoring hypertension (cold air advection, in the center of a cyclone, conditions with cold stress or thermal comfort) was significantly increased by 13% (Chi-squared test for difference of proportions). In contrast, the proportion was decreased by 19% for conditions associated with a higher risk for patients with hypotension and therefore a lower risk for patients with hypertension (warm air advection ahead of warm fronts, conditions with no thermal stress or heat stress, in the center of a cyclone with thermal stress). As many studies have shown that hypertension is a risk factor for ATAAD, our findings support the hypothesized relation between ATAAD and hypertension-favoring weather conditions.