Obvious Seasonal Trend Research Articles

Epidemiological characteristics and toxicant type of acute poisoning cases in China, 2016-2022

Objective: To analyze the acute poison epidemic and provide evidence for developing prevention and control strategies for acute poisoning. Methods: A retrospective analysis was conducted on acute poisoning cases collected from 2016 to 2022 in a health emergency information platform for acute poisoning accidents. The cases were grouped according to the distribution of poisoning occurrence time, geographic distribution, demographic distribution, types of toxicants, poisoning causes, and outcomes. Data were organized and analyzed using Excel 2016 and R 4.2.3. Results: A total of 95 754 acute poisoning cases were included in this study. The primary toxicants were pesticides, drugs, and industrial/household chemicals, accounting for 30.4%, 22.4%, and 20.4% of the total cases, respectively. Acute poisoning occurred throughout the year, with the highest frequency from June to August, accounting for 31.9%. The seasonal distribution varied among different types of toxicants. Except for plant poisoning, which showed a bimodal distribution, the other poisonings showed an unimodal distribution. There was a strong seasonality in fungal poisoning, which peaked in July. There was an obvious seasonality in animal poisoning, with a peak in August. The proportion of biological poisonings in the southwest region was higher than in other regions, including plants, animals, and fungi. There were more females than males, and their education level was mainly junior high school and below (35.2%). The main occupation was farmers (34.2%), and the main causes of poisoning were accidents and suicides. The case fatality rate of all poisoning cases was 1.24%. Pesticide poisoning was the most common type, and chlorfenapyr (11.68%), Diquat (7.23%), and paraquat (7.05%) ranked as the top three toxicants. Conclusions: The occurrence of acute poisoning has an obvious seasonal trend, and the toxicant spectrum of different regions and populations is different. A comprehensive poisoning surveillance system can provide a better understanding of the occurrence of poisonings, and facilitate the formulation of more scientifically precise poisoning prevention and control strategies.

Evolution Characteristics of PM2.5 and O3 and Their Synergistic Effects on Atmospheric Compound Pollution in Tangshan

The concentrations of atmospheric pollutants PM2.5, O3, SO2, NO2, and CO together with the meteorological factors of temperature （T）, relative humidity （RH）, wind speed, and other relevant data in Tangshan from 2015 to 2021 were collected to study the variation characteristics of PM2.5 and O3 at different periods in Tangshan City in the past seven years and their influencing factors, to discuss the contributions of air mass transport to PM2.5 and O3 pollution, and to reveal the synergistic influence mechanism of PM2.5 and O3 on atmospheric compound pollution by using correlation analysis and backward trajectory cluster analysis techniques. The results showed that PM2.5 concentrations in Tangshan decreased year by year from 2015 to 2021, whereas O3 concentration showed a unimodal trend, with the peak appearing in 2017. Both PM2.5 and O3 concentrations showed obvious seasonal variation trends； PM2.5 was characterized by the highest concentration in winter and the lowest concentration in summer, whereas O3 was characterized by the highest concentration in summer and the lowest concentration in winter. In addition, the diurnal variation in PM2.5 showed a bimodal distribution, with the peak occurring during the morning and evening on weekdays, and O3 showed a unimodal distribution, with the peak value appearing during the period with strong ultraviolet radiation in the afternoon. PM2.5 had a significant positive correlation with SO2, NO2, and CO, whereas O3 had a significant positive correlation with radiation and temperature. Under the different pollution conditions, PM2.5 and O3 were affected by air mass transports from different directions. Being impacted by various factors, the synergistic effect of PM2.5 and O3 on atmospheric compound pollution showed an obvious negative effect in winter, whereas there was an obvious positive effect in spring, summer, and autumn. Under the backgrounds of different pollutions, when the concentration of PM2.5 exceeded 150 μg·m-3, the synergistic effect of PM2.5 and O3 showed an obvious negative effect.

A comparative study of satellite-based operational analyses and ship-based in-situ observations of sea surface temperatures over the eastern Canadian shelf

The satellite-based operational sea surface temperature (SST) was compared to the ship-based in-situ SSTs established by the Atlantic Zone Monitoring Program (AZMP) over the eastern Canadian shelf (ECS) for a 3-year anal-ysis period (2005–2007). Two sets of operational SST analyses were considered in this study, with one set produced by the Canadian Meteorological Centre (CMC) and the other produced by the National Centers for Environmental Predic-tion (NCEP). The comparative study indicated that there was no appreciable systematic difference between the CMC and NCEP SST analyses over the ECS. The root mean squared difference (RMSD) between the AZMP ship-based in-situ SSTs and the satellite-based STT analyses over the ECS was about 1.0°C, without any obvious seasonal or geo-graphic trend. The RMSDs were relatively larger over the outer flank of the Grand Banks than the other regions of the ECS, mainly due to dynamically complicated circulation and hydrographic conditions over this shelf break area associated with the Labrador Current.

Submarine groundwater discharge and associated metal elements into an urbanized bay

In this study, geochemical tracers (radium isotopes) and heavy metals (Pb, Zn, Cd, Cr and As) were analyzed to derive the submarine groundwater discharge (SGD) and associated metal fluxes during four seasons in an urbanized bay (Daya Bay, China). Results showed that Pb and Zn were the main pollutants in bay water. SGD was found to exhibit an obvious seasonal trend (autumn > summer > spring > winter). Such seasonal patterns may be related to the hydraulic gradient between groundwater level and sea level, storm surges and tidal range. SGD was a dominant source of marine metal elements, contributing 19 %–51 % of the total inputs of metals into Daya Bay. The bay water was classified as slight pollution to heavy pollution, which could be linked to SGD-derived metal fluxes. This study provides a better understanding of the important role that SGD plays in metal budgets and ecological environments of coastal waters.

The spatial–temporal distribution and etiological characteristics of hand-foot-and-mouth disease before and after EV‑A71 vaccination in Kunming, China, 2017–2020

After vaccination with enterovirus 71 (EV-A71), the prevalence of hand-foot-and-mouth disease (HFMD) remained high, and the spatial–temporal distribution of enteroviruses changed. Therefore, it is essential to define the temporal features, spatial distributions, and epidemiological and etiological characteristics of HFMD in Kunming. Between 2017 and 2020, a total of 36,540 children were diagnosed with HFMD in Kunming, including 32,754 children with enterovirus-positive clinical samples. Demographic, geographical, epidemiological and etiological data of the cases were acquired and analyzed. Other enteroviruses replaced EV-A71, and the incidence of EV-A71 decreased dramatically, whereas coxsackievirus A6 (CV-A6) and coxsackievirus A16 (CV-A16) had substantial outbreaks in 2018 and 2019, respectively. The major and minor peaks all extended for 2–4 months compared to before vaccination with the EV-A71 vaccine. From 2019 to 2020, CV-A6, as the predominant serotype, showed only a single peak. Although a high incidence of HFMD was observed in Guandu, Chenggong and Xishan, the annual incidence of different enterovirus serotypes was different in different regions. In 2017, other enteroviruses were most prevalent in Shilin. In 2018, CV-A16 and CV-A6 were most prevalent in Luquan and Shilin, respectively. In 2019, CV-A16 was most prevalent in Jinning. In 2020, CV-A6 and coxsackievirus A10 (CV-A10) were most prevalent in Luquan and Shilin, respectively. Meanwhile, the epidemic cycle of CV-A6 and CV-A16 was only 1 year, and CV-A10 and other enteroviruses were potential risk pathogens. The spatial and temporal distribution of HFMD varies at different scales, and the incidence of HFMD associated with different pathogens has obvious regional differences and seasonal trends. Therefore, research on multivalent combined vaccines is urgently needed, and proper preventive and protective measures could effectively control the incidence of HFMD-like diseases.

Seasonal Variation and Driving Factors of Nitrate in Rivers of Miyun Reservoir Watershed, North China

In order to identify the seasonal variations and dominant driving factors of NO3-N in rivers, investigations of five consecutive years were conducted in seven rivers of the Miyun Reservoir Watershed. Significant seasonal variation of NO3-N in rivers was separately found in the dormant season (non-growing season) and the growing season. Furtherly, the V-shaped, W-shaped, and indistinct seasonal patterns of NO3-N accounted for 53.0%, 38.7%, and 8.3%, respectively. They were remarkably affected by stream flow, and their significant quadratic function was discovered. The annual maxima and minima of NO3-N corresponded to medium flow in the dormant season and low flow or flood in the growing season, respectively. On one hand, flood mainly played a role in the diluent for the Chao River with high NO3-N, and on the other hand, it acted as a nitrogen source for the Bai River with low NO3-N. The NO3-N was closely correlated with human activities, and this correlation had obvious seasonal change trend. In the dormant season, significant and mostly extremely significant high correlation coefficient (R) values were determined, while partly non-significant with low R values were found in July, August, September, and October. Increasing seasonal variation index of NO3-N from upstream to downstream was found that was gentle for large rivers and sharp for small tributaries. The seasonality of NO3-N was more affected by natural factors, especially flood, than human factors.

Time series analysis of rubella incidence in Chongqing, China using SARIMA and BPNN mathematical models

Chongqing is among the areas with the highest rubella incidence rates in China. This study aimed to analyze the temporal distribution characteristics of rubella and establish a forecasting model in Chongqing, which could provide a tool for decision-making in the early warning system for the health sector. The rubella monthly incidence data from 2004 to 2019 were obtained from the Chongqing Center of Disease and Control. The incidence from 2004 to June 2019 was fitted using the seasonal autoregressive integrated moving average (SARIMA) model and the back-propagation neural network (BPNN) model, and the data from July to December 2019 was used for validation. A total of 30,083 rubella cases were reported in this study, with a significantly higher average annual incidence before the nationwide introduction of rubella-containing vaccine (RCV). The peak of rubella notification was from April to June annually. Both SARIMA and BPNN models were capable of predicting the expected incidence of rubella. However, the linear SARIMA model fits and predicts better than the nonlinear BPNN model. Based on the results, rubella incidence in Chongqing has an obvious seasonal trend, and SARIMA (2,1,1) × (1,1,1) 12 model can predict the incidence of rubella well. The SARIMA model is a feasible tool for producing reliable rubella forecasts in Chongqing.

Niche and interspecific associations of Pseudoanabaena limnetica – Exploring the influencing factors of its succession stage

In aquatic ecosystems, the dynamics of ecological parameters play an important role in community organization. To understand the changes in the phytoplankton community structure in karstic reservoirs, the Hongfeng reservoir in Guizhou plateau was monitored monthly from 2016 to 2019. The results showed that the dominant organisms in phytoplankton comprised five phyla and twelve species during 4 years, among which the proportion of abundance of Pseudoanabaena limnetica begin to rise in 2018 and reached 46.57% in 2019 (the highest during the study period). The niche breadth (0.259–0.925) and overlap value (0–0.991) of P. limnetica have an obvious seasonal trend and are significantly affected by environmental factors such as water temperature, nutrients, and interspecific competition. This is primarily reflected in the high adaptability of the dominant species to changes in the N:P concentration ratio in water. Variance Partitioning Analysis (VPN) results show that the diffusion degree of P. limnetica is the result of the interaction between internal (i.e. interspecific competition, with a contribution rate of 13.4%) and external (i.e. environmental factors, with a contribution rate of 86.6%). The greater the external influence, the higher the diffusion degree. The results of niche-based theories and neutral-based theories showed that the stable community structure (variance rate (VR > 1)) and the excessive fast diffusion rate of dominant species (migration rate (m = 0.84)) may lead to the risk of P. limnetica and other toxic filamentous cyanobacteria blooms. The results provide basic data for the study of early warnings regarding phytoplankton community succession and cyanobacteria blooms in large reservoirs in the karst areas.

Establishment and Evaluation of a Time Series Model for Predicting the Seasonality of Acute Upper Gastrointestinal Bleeding.

ObjectiveWe aimed to establish and evaluate a time series model for predicting the seasonality of acute upper gastrointestinal bleeding (UGIB).MethodsPatients with acute UGIB who were admitted to the Emergency Department and Gastrointestinal Endoscopy Center of Guangdong Provincial Hospital of Traditional Chinese Medicine from January 2013 to December 2019 were enrolled in the present study. The incidence trend of UGIB was analyzed by seasonal decomposition method. Then, exponential smoothing model and autoregressive integrated moving average model (ARIMA) were used to establish the model and forecast, respectively.ResultsFinally, the exponential smoothing model with better fitting and prediction effect was selected. The smooth R2 was 0.586, and the Ljung-Box Q (18) statistic value was 22.272 (P = 0.135). The incidence of UGIB had an obvious seasonal trend, with a peak in annual January and a seasonal factor of 140%. After that, the volatility had gradually declined, with a trough in August and a seasonal factor of 67.8%. Since then, it had gradually increased.ConclusionThe prediction effect of exponential smoothing model is better, which can provide prevention and treatment strategies for UGIB, and provide objective guidance for more medical staff in Emergency Department and Gastrointestinal Endoscopy Center during the peak period of UGIB.

Forecasting the incidence of mumps in Chongqing based on a SARIMA model

BackgroundMumps is classified as a class C infection disease in China, and the Chongqing area has one of the highest incidence rates in the country. We aimed to establish a prediction model for mumps in Chongqing and analyze its seasonality, which is important for risk analysis and allocation of resources in the health sector.MethodsData on incidence of mumps from January 2004 to December 2018 were obtained from Chongqing Municipal Bureau of Disease Control and Prevention. The incidence of mumps from 2004 to 2017 was fitted using a seasonal autoregressive comprehensive moving average (SARIMA) model. The root mean square error (RMSE) and mean absolute percentage error (MAPE) were used to compare the goodness of fit of the models. The 2018 incidence data were used for validation.ResultsFrom 2004 to 2018, a total of 159,181 cases (93,655 males and 65,526 females) of mumps were reported in Chongqing, with significantly more men than women. The age group of 0–19 years old accounted for 92.41% of all reported cases, and students made up the largest proportion (62.83%), followed by scattered children and children in kindergarten. The SARIMA(2, 1, 1) × (0, 1, 1)12 was the best fit model, RMSE and MAPE were 0.9950 and 39.8396%, respectively.ConclusionBased on the study findings, the incidence of mumps in Chongqing has an obvious seasonal trend, and SARIMA(2, 1, 1) × (0, 1, 1)12 model can also predict the incidence of mumps well. The SARIMA model of time series analysis is a feasible and simple method for predicting mumps in Chongqing.

Linear and non-linear combination forecasting model of varicella incidence in Chongqing

Abstract Varicella is a highly infectious contagious disease, and Chongqing is one of the high incidence areas in China. To understand the epidemic regularity and predict the epidemic trend of varicella is of great significance to the risk analysis and health resource allocation in the health sector. First, we used the ‘STL’ function to decompose the incidence of varicella to understand its trend and seasonality. Second, we established SARIMA model for linear fitting, and then took the residual of the SARIMA model as the sample to fit the LS-SVM model, to explain the non-linearity of the residuals. The monthly varicella incidence peaks in April to June and October to December. Mixed model was compared to SARIMA model, the prediction error of the hybrid model was smaller, and the RMSE and MAPE values of the hybrid model were 0.7525 and 0.0647, respectively, the mixed model had a better prediction effect. Based on the study, the incidence of varicella in Chongqing has an obvious seasonal trend, and a hybrid model can also predict the incidence of varicella well. Thus, hybrid model analysis is a feasible and simple method to predict varicella in Chongqing.

Long-Term Air Quality Study in Fairbanks, Alaska: Air Pollutant Temporal Variations, Correlations, and PM2.5 Source Apportionment

As one of the most polluted U.S. cities, Fairbanks was reclassified as a “serious” nonattainment area by the Environmental Protection Agency (EPA) in 2017 for its fine particulate matter (PM2.5) pollution. In this study, November 2013–May 2019 observations of criteria air pollutants (NO2, SO2, CO, O3, PM2.5, and inhalable particulate matter (PM10)) and meteorological parameters (temperature, wind speed, and relative humidity) in Fairbanks were used for temporal variation and correlation analysis, with positive matrix factorization (EPA PMF 5.0) adopted for further PM2.5 source identification. All pollutants exhibited obvious seasonal trends under the influence of climatology, topography, and human activity, while abnormal patterns likely resulted from occasional emission events such as wildfires. Primary and secondary pollutants performed distinctively under similar meteorological conditions due to different decisive factors. Identified PM2.5 sources included sulfate (32.7%), wood smoke (19.3%), gasoline (18.3%), nitrate (15.7%), diesel (9.2%), soil (3.8%), and road salt (1.0%). Compared with the 2005–2012 result, sulfate and nitrate contributions had increased, while wood smoke and diesel contributions had decreased, in which emission control measures as well as a change of sampling sites could play an important role. This systematic analysis offers reference for mitigation measures and pollution prediction. Meanwhile, further field investigation is required for conclusion validation and model improvement.

Using dolphins to catch tuna: Assessment of associations between pantropical spotted dolphins and yellowfin tuna hook and line fisheries in Hawai‘i

In Hawaiian waters fishermen use the association between pantropical spotted dolphins (Stenella attenuata) and yellowfin tuna (Thunnus albacares) to catch tuna. Targeting fishing effort around or in spotted dolphin groups has the potential to lead to bycatch, and anecdotal reports of hooking dolphins exist. We recorded information on fishing vessels associated with spotted dolphin groups from 2008 through 2018 to inform discussions about potential bycatch. Associations occurred from Oʻahu to Hawaiʻi Island, but were most prevalent off Hawaiʻi Island, where 29.7 % of spotted dolphin groups had fishing vessels present. When fishing vessels were present, trolling through the dolphin group envelope was recorded in 91.7 % of encounters, and re-positioning through the dolphin group and dropping hook and line fishing gear at the leading edge of the group was recorded in 54.2 % of encounters (most of which also had vessels trolling through). Associations occurred over all four oceanographic seasons, with no obvious seasonal trend. Off Hawaiʻi Island, fishing vessels with spotted dolphin groups were concentrated in a narrower depth range than dolphin groups without fishing vessels present. Groups with fishing vessels were also concentrated in a smaller geographic area that corresponded to proximity to harbors and boat launches. The number of fishing vessels that associated with spotted dolphin groups off Hawaiʻi Island was estimated in the low hundreds (159, (SD = 12) for 2012; 330 (SD = 17) for 2013). Overall, our results suggest that fishing vessel associations with pantropical spotted dolphins in Hawaiian waters are widespread, occur frequently, and involve many participants, suggesting the risk of accidental hooking may be greater than perceived.

Seasonal and Diurnal Variations in the Priestley–Taylor Coefficient for a Large Ephemeral Lake

The Priestley–Taylor equation (PTE) is widely used with its sole parameter (α) set as 1.26 for estimating the evapotranspiration (ET) of water bodies. However, variations in α may be large for ephemeral lakes. Poyang Lake, which is the largest freshwater lake in China, is water-covered and wetland-covered during its high-water and low-water periods, respectively, over a year. This paper examines the seasonal and diurnal variations in α using eddy covariance observation data for Poyang Lake. The results show that α = 1.26 is overall feasible for both periods at daily and subdaily scales. No obvious seasonal trend was observed, although the standard deviation in α for the wetland was larger than that for the water surface. The mean bias in evaporation estimations using the PTE was less than 5 W·m−2 during both periods, and the root mean square errors were much smaller than the average evaporation measurements at daily scale. U-shaped diurnal patterns of α were found during both periods, due partly to the negative correlation between α and the available energy (A). Compared to the vapor pressure deficit (VPD), wind speed (u) exerts a larger contribution to these variations. In addition, u is positively correlated with α during both periods, however, VPD was positively and negatively correlated with α during the high-water and low-water periods, respectively. Subdaily α exhibited contrasting clusters in the (u, VPD) plane under the same available energy ranges. Our study highlights the seasonal and diurnal course of α and suggests the careful use of PTE at subdaily scales.

Analysis on the groundwater salt dynamic in a monitoring area in Hetao Irrigation District of Inner Mongolia

In order to explore the rule of groundwater salt dynamic in Hetao Irrigation District, a typical monitoring area was selected as the research area in Yongji Irrigation Area of Hetao Irrigation District. The groundwater level and groundwater salinity were analyzed during the year and inter-annual variation in 2008-2013. The groundwater level showed an obvious seasonal change trend during the year variation. The groundwater level was at the peak value after spring irrigation and autumn irrigation. The groundwater level was at the low value before melting and autumn irrigation. The groundwater level had an obvious periodicity during the inter-annual variation. The groundwater level could keep a relatively stable for many years. The groundwater salinity showed an obvious seasonal change trend during the year variation. The groundwater salinity was greatly affected by irrigation and had a decreased trend after irrigation. The groundwater salinity had an obvious periodicity during the inter-annual variation and could keep a relatively stable for many years in cultivated land. The groundwater salinity had an increased trend during the inter-annual variation in wasteland. The wasteland was the drainage area for cultivated land. The wasteland had an obvious role in adjusting salt dynamic balance in Hetao Irrigation District.

Characteristics of Atmospheric PM2.5 Pollution and Its Influence on Visibility in Background Areas of Ji'nan

In order to study the seasonal variations in the chemical composition of atmospheric particulate matter with diameters less than 2.5 μm (PM2.5) and its influence on visibility in background areas, atmospheric PM2.5 samples were collected in spring, summer, autumn, and winter 2016 at Qixingtai in Ji'nan. The pollution characteristics of water-soluble ions components, organic carbon (OC), and elemental carbon (EC) were analyzed, and their regional transmission contributions were studied. The results show that NH4+, SO42-, and NO3- were the main components of water-soluble ions, accounting for 90.24% of the annual total ion concentration. The secondary water soluble inorganic ions were polluted severely. NO3-/SO42- presented obvious seasonal variations of high (low) levels in winter (summer). In each season, SO42- and NH4+ existed mainly in the form of (NH4)2SO4. The value of secondary OC (SOC)/OC ranged from 21.17% to 54.21%, indicating the presence of relatively severe secondary organic pollution in this area. The sulfur oxidation ratio (SOR) value in all seasons was greater than 0.1, indicating that the secondary generation of SO42- occurs in all seasons in this region, and the value of nitrogen oxidation ratio (NOR) in all seasons was higher than the SOR value. The secondary transformation of NO2 in the Qixingtai region was stronger than that of SO2. The range of atmospheric extinction coefficient (Bext) was 172.68-320.61 Mm-1, with an annual mean of 256.48 Mm-1. The atmospheric extinction coefficient showed an obvious seasonal trend of the lowest (highest) in summer (winter). The backward airflow trajectory shows that the Qixingtai was affected mainly by the long-distance transmission from Northwest China and the ocean in spring and summer and by local sources in autumn and winter. A comparison of the characteristics of atmospheric PM2.5 pollution in Ji'nan in 2008 revealed that the influence of motor vehicles on the atmospheric environment has been significantly improved.

The association between air pollution and preterm birth and low birth weight in Guangdong, China

BackgroundA mountain of evidence has shown that people’s physical and mental health can be affected by various air pollutions. Poor pregnancy outcomes are associated with exposure to air pollution. Therefore, this study aims to investigate the association between air pollutions (PM2.5, PM10, SO2, NO2, CO, and O3) and preterm birth/low birth weight in Guangdong province, China.MethodAll maternal data and birth data from January 1, 2014 to December 31, 2015 were selected from a National Free Pre-pregnancy Check-ups system, and the daily air quality data of Guangdong Province was collected from China National Environmental Monitoring Center. 1784 women with either preterm birth information (n = 687) or low birth weight information (n = 1097) were used as experimental group. Control group included 1766 women with healthy birth information. Logistic regression models were employed to evaluate the effects of air pollutants on the risk of preterm birth and low birth weight.ResultsThe pollution levels of PM2.5, PM10, SO2, NO2, CO, and O3 in Guangdong province were all lower than the national air pollution concentrations. The concentrations of PM2.5, PM10, SO2, NO2 and CO had obvious seasonal trends with the highest in winter and the lowest in summer. O3 concentrations in September (65.72 μg/m3) and October (84.18 μg/m3) were relatively higher. After controlling for the impact of confounding factors, the increases in the risk of preterm birth were associated with each 10 μg/m3 increase in PM2.5 (OR 1.043, 95% CI 1.01–1.09) and PM10 (OR 1.039, 95% CI 1.01~1.14) during the first trimester and in PM2.5 (OR 1.038, 95% CI 1.01~1.12), PM10 (OR 1.024, 95% CI 1.02~1.09), SO2 (OR 1.081, 95% CI 1.01~1.29), and O3 (OR 1.016, 95% CI 1.004~1.35) during the third trimester. The increase in the risk of low birth weight was associated with PM2.5, PM10, NO2, and O3 in the first month and the last month.ConclusionThis study provides further evidence for the relationships between air pollutions and preterm birth/low birth weight. Pregnant women are recommended to reduce or avoid exposure to air pollutions during pregnancy, especially in the early and late stages of pregnancy.

Impact of Air Mass Conditions and Aerosol Properties on Ice Nucleating Particle Concentrations at the High Altitude Research Station Jungfraujoch

Ice nucleation is the source of primary ice crystals in mixed-phase clouds. Only a small fraction of aerosols called ice nucleating particles (INPs) catalyze ice formation, with their nature and origin remaining unclear. In this study, we investigate potential predictor parameters of meteorological conditions and aerosol properties for INP concentrations at mixed-phase cloud condition at 242 K. Measurements were conducted at the High Altitude Research Station Jungfraujoch (Switzerland, 3580 m a.s.l.), which is located predominantly in the free troposphere (FT) but can occasionally receive injections from the boundary layer (BLI). Measurements are taken during a long-term study of eight field campaigns, allowing for the first time an interannual (2014–2017) and seasonal (spring, summer, and winter) distinction of high-time-resolution INP measurements. We investigate ranked correlation coefficients between INP concentrations and meteorological parameters and aerosol properties. While a commonly used parameterization lacks in predicting the observed INP concentrations, the best INP predictor is the total available surface area of the aerosol particles, with no obvious seasonal trend in the relationship. Nevertheless, the predicting capability is less pronounced in the FT, which might be caused by ageing effects. Furthermore, there is some evidence of anthropogenic influence on INP concentrations during BLI. Our study contributes to an improved understanding of ice nucleation in the free troposphere, however, it also underlines that a knowledge gap of ice nucleation in such an environment exists.

硇洲岛海域环境因子的季节变化及对硇洲马尾藻等大型海藻的影响

本研究于2011年6月至2012年3月、2016年对湛江硇洲岛海域进行采样调查，以分析海水中各环境因子的季节变化情况及对硇洲马尾藻等大型海藻的影响。结果表明，温度变化趋势为夏季 > 春季 > 秋季 > 冬季，冬季的温度最低；盐度的整体变化趋势是夏季 > 春季 > 冬季 > 秋季，盐度最低的是秋季；pH变化趋势是秋季 > 春季 > 冬季 > 夏季；悬浮物变化趋势为春季 > 夏季 > 秋季 > 冬季；叶绿素a最高值出现在秋季和夏季，冬季质量浓度最低；TOC含量的整体变化为夏季 > 春季 > 秋季 > 冬季；氨氮、硝氮、磷酸盐具有较明显的季节变化规律，亚硝氮与硅酸盐则没有表现出明显的规律。调查结果显示，硇洲马尾藻等大型海藻的生长繁殖与水温、营养盐、透明度、悬浮物等环境因子的季节变化有关，也与水产养殖、渔民采收、渔船数量等人为因素都有关。 The seasonal changes of the environment factors and its affection to the large alga from intertidal zone in Naozhou Island were studied in this study. The results showed that trend of the temperature was summer > spring > autumn > winter, for salinity it was summer > spring > winter > autumn, for pH it was autumn > spring > winter > summer, for SS it was spring > summer > autumn > winter, and for chlorophyll a there were the highest concentrations in autumn and summer, lowest in winter. The trend of TOC was summer > spring > autumn > winter too, like the temperature; unlike nitrite and silicate, there were obvious seasonal changing trends for nitrate, ammonia nitrogen and phosphate. In brief, the growth and reproduce of the large alga were not only determined by the environment factors but also the human beings.

Distribution, partitioning and sources of polycyclic aromatic hydrocarbons in the water–SPM–sediment system of Lake Chaohu, China

The residual levels of polycyclic aromatic hydrocarbons (PAHs) in the water, suspended particular matter (SPM) and sediment from Lake Chaohu were measured with a gas chromatograph–mass spectrometer (GC–MS). The spatial–temporal distributions and the SPM–water partition of PAHs and their influencing factors were investigated. The potential sources and contributions of PAHs in the sediment were estimated by positive matrix factorization (PMF) and probabilistic stable isotopic analysis (PSIA). The results showed that the average residual levels of total PAHs (PAH16) in the water, SPM and sediment were 170.7±70.8ng/L, 210.7±160.7ng/L and 908.5±1878.1ng/g dry weight, respectively. The same spatial distribution trend of PAH16 in the water, SPM and sediment was found from high to low: river inflows>western lake>eastern lake>water source area. There was an obvious seasonal trend of PAH16 in the water, while no obvious seasonal trend was found in the SPM. The residues and distributions of PAHs in the water, SPM and sediment relied heavily on carbon content. Significant Pearson correlations were found between LogKoc and LogKow as well as some hydro-meteorological factors. Three major sources of PAHs including coal and biomass combustions, and vehicle emissions were identified.