Area In Winter Research Articles

Atmospheric Mercury Concentrations and Isotopic Compositions Impacted by Typical Anthropogenic Mercury Emissions Sources.

Coal-fired power plants (CFPPs) and cement plants (CPs) are important anthropogenic mercury (Hg) emission sources. Mercury speciation profiles in flue gas are different among these sources, leading to significant variations in local atmospheric Hg deposition. To quantify the impacts of Hg emissions from CFPPs and CPs on local-scale atmospheric Hg deposition, this study determined concentrations and isotopes of ambient gaseous elemental mercury (GEM), particulate-bound mercury (PBM), and precipitation total Hg (THg) at multiple locations with different distances away from a CFPP and a CP. Higher concentrations of GEM and precipitation THg in the CFPP area in summer were caused by higher Hg emission from the CFPP, resulting from higher electricity demand. Higher concentrations of GEM, PBM, and precipitation THg in the CP area in winter compared to those in summer were related to the higher output of cement. Atmospheric Hg concentration peaked near the CFPP and CP and decreased with distance from the plants. Elevated GEM concentration in the CFPP area was due to flue gas Hg0 emissions, and high PBM and precipitation Hg concentrations in the CP area were attributed to divalent Hg emissions. It was estimated that Hg emissions from the CFPP contributed 58.3 ± 20.9 and 52.3 ± 25.9% to local GEM and PBM, respectively, and those from the CP contributed 47.0 ± 16.7 and 60.0 ± 25.9% to local GEM and PBM, respectively. This study demonstrates that speciated Hg from anthropogenic emissions posed distinct impacts on the local atmospheric Hg cycle, indicating that Hg speciation profiles from these sources should be considered for evaluating the effectiveness of emission reduction policies. This study also highlights the Hg isotope as a useful tool for monitoring environmental Hg emissions.

Role of Ammonia in Aerosol Liquid Water, pH, and Secondary Inorganic Aerosols Formation at an Ammonia-rich City in Changzhou

Ammonia （NH3） is an important alkaline reactive nitrogen, which, as a precursor of fine particulate matter, raises public health issues. In this study, online NH3, SO2, NO2, PM2.5, and its water-soluble inorganic ions were detected to deduce the influence of NH3 on aerosol liquid water content （AWC） and aerosol pH, including the formation of water-soluble secondary ions in PM2.5 in winter in Changzhou, an ammonia-rich city in the Yangtze River Delta area in winter. The results showed that NH4+ mainly existed in the form of NH4NO3 and （NH4）2SO4, and the remaining NH4+ existed as NH4Cl. Owing to the NH3-NH4+ buffer system, the aerosol pH values were found at 4.2 ± 0.4, which was positively correlated with the NH3 content. The aerosol pH value variation narrowed with the increase in PM2.5 concentration and tended to be between 4 to 5. AWC increased exponentially with the increase in humidity and SNA content, among which NH4NO3, （NH4）2SO4, and NH4Cl contributed 58.5%, 18.4%, and 8.3%, respectively, due to their hygroscopicity. Aerosol pH, AWC, and NH3-NH4+ conversion promoted the gas-to-particle conversion of SO2 and NO2. In Changzhou, rich NH3-NH4+ were found to maintain relatively high pH values, push up AWC, and promote the heterogeneous reaction of SO2, whereas NO3- generation was dominated by a homogeneous reaction, which was accelerated by NH3. According to the simulation results, relatively noticeable changes in aerosol pH and AWC could be found by the reduction of up to 30% of NH3.

ВЛИЯНИЕ УСЛОВИЙ ХРАНЕНИЯ АВТОБУСОВ В КРЫТЫХ ОТАПЛИВАЕМЫХ СТОЯНКАХ НА ИНТЕНСИВНОСТЬ КОРРОЗИОННОГО ИЗНАШИВАНИЯ КУЗОВОВ

The efficiency of the rolling stock of road transport is determined by both the efficiency of organizing transport work and the cost of ensuring the operability of vehicles. One of the current problems with the operation of buses is the corrosive destruction of their bearing structure, which leads to both a reduction in the operating time of vehicles and an increase in the operating costs associated with the overhaul of bodies. During the work, it was revealed that the main reasons for the intensive corrosion destruction of bus bodies are insufficient corrosion resistance of metals that are used in the manufacture of the body frame. The main places of occurrence of body corrosion foci are: wheel arches; rear and lower parts of the bus, which are more affected by adverse road conditions; upper and lower parts of window openings in case of seal leakage. Studies were conducted on the temperature and relative humidity of the indoor heated bus parking area in winter. Based on the results of the study, dependencies were obtained: air temperature in the indoor parking room from ambient temperature, relative air humidity in the indoor parking room from relative ambient air humidity, relative air humidity in the indoor parking room and ambient temperature. The nature of air exchange between the parking room and the environment has been established. According to the results of the study, factors contributing to the intensive corrosive destruction of bus bodies were established.

ФОРМИРОВАНИЕ ХИМИЧЕСКОГО СОСТАВА ВОД СЕВЕРНОГО БАЙКАЛА В ЗОНЕ СМЕШЕНИЯ С ВОДАМИ ПРИТОКОВ

The results of studying the chemical composition of water in Northern Baikal and in the rivers flowing into it are analyzed. It is shown that the influence of river water on forming the chemical composition of water in this part of the lake is observed at the distance of 1-3 km from the cofferdam separating the Upper Angara delta from Lake Baikal. In spring and early summer, the expansion of river water in the lake is constrained by a thermal bar. In summer, a biological barrier is formed in the mixing zone, where the minimum biogenic element concentrations of and maximum phytoplankton concentrations are registered. The increased concentrations of phosphorus have been revealed in the shallow area in winter, which points to the contamination of bottom sediments and secondary pollution of water. The increased content of phosphorus in the water may be a sign of the eutrophication of Northern Baikal.

Analysis of Acoustic Elements in Northwest Pacific Ocean Based on Operational MODAS Data and Its Response to Kuroshio Seasonal Variation

This study utilized operational MODAS (Modular Ocean Data Assimilation System) data to analyze the seasonal variation of acoustic elements of Northwest Pacific Ocean (NWPO). Combining the seasonal variation of the Kuroshio, it further investigated the impact of the Kuroshio seasonal variation on acoustic properties. The results indicate that the distribution of acoustic elements have significant seasonal variation, with a strong correlation between sonic layer depth and mixed layer depth. The acoustic thermocline depth and thermocline depth show significant correlations in the whole area in winter and spring, while in the rest two seasons, it only occurs in low latitude, the southern part of South China Sea (SCS), and also the Kuroshio area.

Terrestrial and Biological Activities Shaped the Fate of Dissolved Organic Nitrogen in a Subtropical River‐Dominated Estuary and Adjacent Coastal Area

AbstractEstuaries are key areas for terrestrial material transport and marine biogeochemical processes, particularly those of dissolved inorganic nitrogen (DIN) and dissolved organic nitrogen (DON). However, the fate of DON in estuaries with a high runoff remains poorly understood. In this study, we explored the translocation and transformation of DON in the Pearl River Estuary (PRE) and adjacent coastal areas of southern China based on DON concentrations, optical and fluorescence characteristics, and environmental parameters. The results revealed that DIN and DON exhibited dissimilar distributions. The distribution of DIN was primarily influenced by freshwater‐seawater mixing. In contrast, biological processes and freshwater‐seawater mixing shaped the distribution of DON. High levels of DON in the terrestrial‐dominated zone were predominantly anthropogenic sources through terrestrial inputs, whereas DON in the freshwater‐seawater mixing zone and seawater‐based zone were mainly influenced by biological activities, as high concentrations of Chla were observed in these two areas. DON exhibits fast dilution in low‐salinity areas and retention in moderate‐salinity areas (freshwater‐seawater mixing area) in summer and winter, while undergoes a rapid decrease in open water areas during winter. Consequently, DON in the PRE and adjacent coastal areas exhibited nonconservative mixing despite seasonal variations. These findings provide novel insights into the role of DON in nitrogen biogeochemical processes in river‐dominated estuaries and adjacent coastal areas.

From winter to late summer in the northwestern Barents Sea shelf: Impacts of seasonal progression of sea ice and upper ocean on nutrient and phytoplankton dynamics

Strong seasonality is a key feature of high-latitude systems like the Barents Sea. While the interannual variability and long-term changes of the Barents Sea are well-documented, the seasonal progression of the physical and biological systems is less known, mainly due to poor accessibility of the seasonally ice-covered area in winter and spring. Here, we use an extensive set of physical and biological in situ observations from four scientific expeditions covering the seasonal progression from late winter to late summer 2021 in the northwestern Barents Sea, from fully ice-covered to ice-free conditions. We found that sea ice meltwater and the timing of ice-free conditions in summer shape the environment, controlling heat accumulation, light and nutrient availability, and biological activity vertically, seasonally, and meridionally. In March and May, the ocean north of the Polar Front was ice-covered and featured a deep mixed layer. Chlorophyll-a concentrations increased strongly from March to May along with greater euphotic depth, indicating the beginning of the spring bloom despite the absence of surface layer stratification. By July and in September, sea ice meltwater created a shallow low-density surface layer that strengthened stratification. In open water, chlorophyll-a maxima were found at the base of this layer as surface nutrients were depleted, while in the presence of ice, maxima were closer to the surface. Solar heating and the thickness of the surface layer increased with the number of ice-free days. The summer data showed a prime example of an Arctic-like space-for-time seasonal variability in the key physical and biological patterns, with the summer situation progressing northwards following sea ice retreat. The amount of sea ice melt (local or imported) has a strong control on the conditions in the northwestern Barents Sea, and the conditions in late 2021 resembled pre-2010 Arctic-like conditions with high freshwater content and lower ocean heat content.

Investigating PM2.5 toxicity in highly polluted urban and industrial areas in the Middle East: human health risk assessment and spatial distribution

Exposure to particulate matter (PM) can be considered as a factor affecting human health. The aim of this study was to investigate the concentration of PM2.5 and heavy metals and their influence on survival of A549 human lung cells in exposure to PM2.5 breathing air of Ahvaz city. In order to assess the levels of PM2.5 and heavy metals, air samples were collected from 14 sampling stations positioned across Ahvaz city during both winter and summer seasons. The concentration of heavy metals was determined using ICP OES. Next, the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] was employed to ascertain the survival rate of A549 cells. The findings from this research demonstrated that average PM2.5 of the study period was (149.5 μg/m3). Also, the average concentration of PM2.5 in the urban area in winter and summer was (153.3- and 106.9 μg/m3) and in the industrial area this parameter was (191.6 and 158.3 μg/m3). The average concentration of metals (ng/m3) of urban areas against industrial, Al (493 vs. 485), Fe (536 vs. 612), Cu (198 vs. 212), Ni (128 vs. 129), Cr (48.5 vs. 54), Cd (118 vs. 124), Mn (120 vs. 119), As (51 vs. 67), Hg (37 vs. 50), Zn (302 vs. 332) and Pb (266 vs. 351) were obtained. The results of the MTT assay showed that the highest percentage of cell survival according to the exposure concentration was 25 > 50 > 100 > 200. Also, the lowest percentage of survival (58.8%) was observed in the winter season and in industrial areas with a concentration of 200 μg/ml. The carcinogenic risk assessment of heavy metals indicated that except for Cr, whose carcinogenicity was 1.32E−03, other metals were in the safe range (10–4–10–6) for human health. The high concentration of PM2.5 and heavy metals can increase respiratory and cardiovascular diseases and reduce the public health level of Ahvaz citizens.

Seasonal variations in the diversity and benthic community structure of subtidal artificial oyster reefs adjacent to the Luanhe River Estuary, Bohai Sea

Artificial oyster reefs provide important spawning and nursery grounds for a variety of fishes and large mobile crustaceans. Between July 2016 and May 2017, seasonal surveys of species composition and community structure were performed in the artificial oyster reef area and control area adjacent to the Luanhe River Estuary in China. During the survey year, 56 species belonging to 50 genera, 45 families, and 19 orders were recorded. The dominant economically important fish and mobile crustaceans were Hexagrammos otakii, Pholis fangi, Sebastes schlegelii, Charybdis japonica, and Oratosquilla oratoria. Resident fishes belonged to the Cynoglossidae, Paralichthyidae, Pleuronectidae, and Gobiidae families. Seasonally important fish species included Lateolabrax japonicus, Konosirus punctatus, Thryssa kammalensis, Hexagrammos agrammus, and Acanthopagrus schlegelii. The ranges of H' values among stations were 1.18–2.16, 0.65–1.75, 1.18–2.06, and 0.62–1.92 in spring, summer, autumn, and winter, respectively. The benthic organisms present in the community of artificial oyster reef areas can be classified into groups according to month and season. The abundance biomass curves showed that the oyster reef area in spring, autumn, and winter experienced low disturbance, whereas the community structure in summer was subject to large variations from external disturbance. We also found that as the age of the oyster reefs increased, the percentage of oysters in the low shell height group (< 40 mm) decreased. The oyster density was 324 ind/m2 for the reef created in 2016, 724 ind/m2 for the reef created in 2015, and 364 ind/m2 for the reef created in 2013. These findings can be used to develop suitable management strategies for the sustainable maintenance of artificial oyster reef ecosystems.

Optimization of Landscape Spatial Configuration and Form for Thermal Comfort: A Case Study of Urban Square, Shanghai

Outdoor public spaces that provide a comfortable microclimate significantly contribute to urban livability. However, more elaborate investigations are needed to enhance the research-based design of landscape spatial form for optimal thermal comfort performance. This study aimed to optimize the morphological design of urban squares considering summer and winter microclimates by integrating multiple landscape elements of vegetation, waterbodies, buildings, and ground. The built environment microclimate simulation and validation of multi-physics coupling were conducted for thermal comfort, planar heterogeneity diagramming, and spatial typology identification. Further, research through design (RtD) was applied to reconstruct various spatial configurations and orientation forms to compare the relative thermal comfort areas of these geometrical prototypes in the target time period and square core zone. Among the landscape types, two identified spatial types for achieving better thermal comfort are the opening of a windward enclosure structure (ECS) that draws wind into the square in summer and an ECS without a windward opening that creates a more extended wind protection area in winter. Moreover, results of RtD show that the prototype with the smallest orientation angle to the prevailing wind direction has the most optimized thermal comfort during summer, while the form with a smaller angle to the prevailing wind direction is more favorable in winter. These findings provide methodological guidance for climate-adapted landscape square form optimization.

Fisheries measures protect European seabass groups with distinct habitat use differently

Abstract We investigated the movements of European seabass, Dicentrarchus labrax, to understand habitat use and connectivity to evaluate how individual seabass are protected by the spatiotemporal fisheries restrictions in place. We tagged seabass with acoustic transmitters in a study area in the Port of Zeebrugge (Belgium) in the southern North Sea. The 370,200 detections of 57 seabass in the study area revealed high residency in the period from late March–May to September–November, as well as high site fidelity (70.7%). Whereas the majority of seabass left the area in winter, 13 seabass stayed in the harbour experiencing temperatures as low as 2.8°C. Two groups of seabass were identified having different core movement areas in the inner and outer harbours, although movement between the two areas was possible. The distinct differences in habitat use between these groups resulted in a significantly different level of exposure to fisheries under the same policy framework. By quantifying the level of protection of seabass, based on the spatiotemporal fisheries management in place, our study underlines the importance of taking into account movement behaviour when evaluating conservation measures.

Evaluation of Climatic Comfort and its Role in Tourist Attractions in Sulaymaniyah Governorate

Human health and discomfort are influenced by many different environmental conditions that have a direct impact on human feeling, although different research has been attempted to find a suitable solution for it, but still considered as a major obstacle due to the differences in atmospheric elements from one region to another, as well as the differences in the human body›s ability to feel comfortable or uncomfortable in person to person according to different regions. Using temperature and humidity index (THI) Temperature Humidity Indexand air-cooling index (K) Wind chill index and their effect on human peace and tourists visiting Sulaimani province. this research consists of two main axes, the first one is e the atmospheric elements effective on human comfort in the research area, and the second axis is about the effect of atmospheric stability on attracting tourists to the researched area, as this area is known for its low temperatures, especially in winter, as it reaches in some parts to zero Celsius, for instance in Penguin region, which leads to snowfall. This area can be used as a tourist area in winter. In addition to the low temperatures in summer, especially in mountainous areas, this will attract a large number of tourists to the research area, so efforts should be made to provide more services to the tourist areas in a way that tourists do not feel uncomfortable in the surrounding environment and in a way that is compatible with the nature of the area.

Spatiotemporal dynamics analysis of surface water body and snow cover area to climate change in Gilgit Baltistan, Pakistan

ABSTRACT Surface water and snow cover in mountainous areas are sensitive to climate change. Pakistan’s irrigation water supply primarily depends on the Indus River. Identifying the spatio-temporal dynamics, response patterns of snow cover area (SCA) and surface water bodies (SWB) to climate change are vital for understanding the changes in the hydrological process of the Indus basin. Therefore, the SWB area was investigated using surface reflectance data (MOD09A1) from the Moderate Resolution Imaging Spectroradiometer (MODIS) and SCA changes were examined using MODIS snow cover data (MOD10A2) from 2009 to 2018 in Gilgit Baltistan with respect to climatic variables. According to results the SWB area in Gilgit Baltistan, for annual, summer and winter, changes at the rate of −0.00057% yr−1 (p > 0.05), −0.00042% yr−1 (p > 0.05) and 0.00037% yr−1 (p > 0.05), respectively. Moreover, annual mean temperature and the SWB exhibited a negative correlation (r = −0.244, p > 0.05) and correlation between SWB and total annual precipitation was positive (r = 0.535, p > 0.05). However, SCA of Gilgit Baltistan changed at the rate of −0.396% yr−1 (p < 0.05), −0.940% yr−1 (p < 0.05) and −0.253% yr−1 (p > 0.05) for annual, summer and winter, respectively. Furthermore, annual mean temperature and SCA exhibited a negative correlation (r = −0.731, p < 0.05), whereas annual total precipitation and SCA showed a positive correlation (r = 0.636, p < 0.05). These results indicated that climate had been significantly affected the SCA and SWB of the Gilgit Baltistan.

A QUICK SEASONAL DETECTION AND ASSESSMENT OF INTERNATIONAL SHADEGAN WETLAND WATER BODY EXTENT USING GOOGLE EARTH ENGINE CLOUD PLATFORM

Abstract. Understanding the variation of Water Extent (WE) can provide insights into Wetland conservation and management. In this study, and-inter inner-annual variations of WE were analyzed during 2019–2021 to understand the spatiotemporal changes of the International Shadegan Wetland, Iran. We utilized a thresholding process on Modified Normalized Difference Water Index (MNDWI) to extract the WE quickly and accurately using the Google Earth Engine (GEE) platform. The water surface analysis showed that: (1) WE had a downward trend from 2019 to 2021, with the overall average WE being 1405.23 km2; (2) the water area reached its peak due to the water supply to International Shadegan Wetland through the Jarahi River and upstream reservoirs at the end of 2019 and the beginning of 2020, and the largest water body appeared in Winter 2019, reaching 1953.31 km2. In contrast, the smallest water body appeared in Autumn 2021, reaching 563.56 km2; (3) The WE of the wetland showed predictable seasonal characteristics. The water area in Winter was the largest, with an average value of 1829.1 km2, while it was the smallest in Summer, with an average value of 1100.3 km2; (4) The average water area in 2019 was 1490.5 km2 whereas in 2020 and 2021 decreased by 9% and 25%, respectively, and reached 968.6 km2 and 811.9 km2. Finally, to evaluate the proposed model, its results were compared with the Random Forest (RF) classification results. Accordingly, Histogram Analysis (HA) classification achieved 94.6% of the average overall accuracy and the average Kappa coefficient of 0.93, but the RF method obtained 95.38% of the average overall accuracy and an average Kappa coefficient of 0.94.

Optimization Methods of Urban Green Space Layout on Tropical Islands to Control Heat Island Effects

With the rapid increase in demand for the construction and development of island cities in the South China Sea, the urban heat island phenomenon in such cities should become a key factor to be considered in future urban planning. This paper took Sanya, China as a typical case, and long-term field experiments were conducted in the Mangrove Bay Area in summer and winter. An innovative urban green space cooling model was proposed, using the “green space cooling index” to quantitatively characterize the green space cooling effect, and aiming to minimize the intensity of urban heat islands. This paper studied the optimization method of green space planning and layout under the constraint of a centralized green space total area. Moreover, a genetic algorithm was adopted to optimize the calculation and the layout of the urban green space. The experimental results showed that the urban heat island intensity was more significant at night and was less effective in the daytime during summer. In winter, the urban heat island intensity had a greater effect in the daytime and was less influential at night. Finally, optimization results indicated that the average urban heat island intensity in summer was reduced by 8.8% under the optimal layout urban green space of 0.025 km2. The maximum reduction in heat island intensity occurred at 7:00 am (0.48 °C). When 0.0625 km2 urban green space was planned, the average urban heat island intensity index in summer was reduced to 0.27 °C, with a decrease of 20.5%.

Detecting geothermal anomalies using Landsat 8 thermal infrared remote sensing data in the Ruili Basin, Southwest China.

With the recent increase in global focus on green energy, the application of thermal infrared remote sensing data for the detection of geothermal anomalies has attracted wide attention as it can overcome the difficulty of using only ground surveying. This study aimed to highlight areas of geothermal anomalies with land surface temperature (LST) time series data in winter derived from thermal infrared remote sensing. To extract LST anomaly areas in the Ruili Basin for geothermal prospecting, nine types of data on the study area in winter during 2014 ~ 2021 from Landsat 8 were analyzed. Landsat 8 LST inversion data based on the mono-window algorithm (MWA) can be used to identify hot springs, volcanoes, and other heat-related phenomena. Superimposing LST anomalies for each cycle through drilling data, excluding the heat island effect, geothermal anomaly regions could be plotted. The results show that the accuracy of MWA LST varied within 2K, which is acceptable for geothermal energy and higher than those of the radiative transfer equation (RTE) algorithm and MODIS LST products. Three high-LST regions in the southeast of the study area were identified as geothermal anomaly areas (A, B, and C), and region B was further verified through a comprehensive field investigation of geothermal wells, supplemented by the temperature gradient (TG) method. The findings reveal that the distribution of geothermal anomaly areas and high-LST areas are highly consistent with the northeast trending fault structure; faults act as thermal channels and help in accurately detecting local LST anomalies. Overall, the infrared remote sensing method proved to be a valid technique for detecting LST anomalies. Considering the synergy between thermal infrared surface detection and subsurface exploration methods, the identification of known geothermal fields (B) and other possible areas (A and C) has significance in the upscaling of local geologic information to regional prospecting, thus providing a direction for future geothermal research.

Water Circulation, Temperature, Salinity, and pCO2 Distribution in the Surface Layer of the East Kamchatka Current

The ship-borne observations of the temperature, salinity, pCO2 (1995–2020) and satellite geostrophic velocity fields, SST, and chlorophyll concentration are used to identify the factors that determine the spatio-temporal variability of seawater parameters on the western boundary of the subarctic North Pacific. In winter, the surface layer of the East Kamchatka Current (EKC) was characterized by two types of water: the waters with a negative temperature (−1.0–−0.5 °C) and salinity of 32.4–32.9 and waters with a positive temperature (0.4–1.7 °C) and salinity of 33.0–33.1. The source of water with negative (positive) temperature and decreased (increased) salinity for the EKC zone is the Bering Sea shelf (Aleutian Basin). The surface waters in the eastern Kamchatka area in winter were close to gas equilibrium with the atmosphere or supersaturated with carbon dioxide (pCO2 = 380–460 µatm). In summer, extremely low pCO2 values (140–220 µatm) in the surface layer of the eastern Kamchatka and the northern Kuril Islands regions have been associated with the decreased salinity (32.1–32.6) of the waters. The distributions of the temperature, salinity, and pCO2 in the surface layer of the central Kuril Islands are determined by the location and intensity of the Kuril eddies and the EKC stream jets. The water mixing in the central Kuril Straits and the Kruzenshterna Bank area leads to increased salinity (33.2–33.4) and high values of pCO2 (480–670 µatm) in the surface layer of the EKC. The comparison of the pCO2 data collected in winter demonstrates an increase in pCO2 between 1998/2001 and 2018/2020 at about 50 µatm in the surface waters with a salinity of 33.0–33.1, which is in agreement with an increase in pCO2 in the atmosphere at 46 µatm (from 368 to 414 µatm) during this period.

Spatial-temporal variability of climate indices in Chungcheong provinces of Korea: Application of graphical innovative methods for trend analysis

Climate change causes unprecedented damage in form of climate extreme events such as floods and drought, especially in the agricultural sector. Understanding the variations and trends of climate characteristics is a step toward mitigating climate-related disasters. This study investigates the annual and seasonal spatial-temporal variability of UNEP and De Martonne climate indices from 10 synoptic stations distributed homogeneously over the Chungcheong Provinces in Korea from 1974 to 2019. The spatial assessment of the variability of climate indices was conducted using the inverse distance weighting (IDW) interpolation method. The annual and seasonal trends were assessed using innovative trend analysis (ITA), while a further trend assessment on a seasonal scale was conducted using innovative polygon trend analysis (IPTA) to reveal periodic features and trend transitions. The results of the ITA were compared to the classical Mann-Kendall (MK) and Modified Mann-Kendall (MMK) trend methods. The findings revealed that the Chungcheong Provinces is a wet climate dominance on an annual scale, with a high occurrence frequency of humid to extreme humid climates. However, there are variations in the climatic classes of UNEP and De Martonne indices on the seasonal timescale and across the stations. The spatial assessment indicated the dominance of moderate climatic conditions, while the heavy climatic condition is consistent at the far-end northeast. The ITA shows significant (95% confidence level) upward trends on an annual scale at 50 and 60% of the stations in UNEP and De Martonne indices, respectively. Moreover, an increasingly significant trend dominated the summer and autumn, while spring and winter seasons exhibited significant decreasing trends. The IPTA shows a dominant transition from the increasing area in autumn to decreasing area in winter, while summer consistently transited in the increasing region at almost all the stations. Both climate indices demonstrate homogeneous and isotropic behaviors and nearly stable conditions. Furthermore, ITA and MK trend statistics indicate a good positive correlation (r > 0.50). The findings of this study are important for the ongoing climate-change-related policy in the agricultural sector in Korea.

Atmospheric conditions conducive to marine fog over the northeast Pacific in winters of 1979–2019

Observations show that the northeast Pacific (NEP) is a fog-prone area in winter compared with the northwest and central Pacific where fog rarely occurs in winter. By synthesizing observations and reanalysis results from 1979 to 2019, this study investigates the atmospheric circulation and marine atmospheric boundary layer structure associated with marine fog over the NEP in winter. Composite analysis shows that the eastern flank of the Aleutian low and the northwestern flank of the Pacific subtropical high jointly contribute to a northward air flow over the NEP. Under such conditions, warm and moist air flows through a cooler sea surface and facilitates the formation of advection-cooling fog. The air near the sea surface in foggy areas is cooled by the downward sensible heat flux. The smaller upward latent heat flux (∼10 W m−2) compared to the surrounding area (&gt;60 W m−2) demonstrates that the moisture originates from the advection instead of local evaporation. The lower (at 925 to 875 hPa) and stronger (up to 0.08 K hPa−1) inversion layer, compared with cloudy cases and the turbulence in the lower atmosphere (below 975 hPa), also promotes fog formation and evolution. Approximately 68% of all fog cases (42242) show positive differences between surface air temperature (SAT) and sea surface temperature (SST), while 32% are negative, during southerly winds. Composite analysis of the latter shows lower specific humidity above the inversion bottom compared to the former. Dry air enhances longwave radiative cooling from the fog top, favoring cooling of the fog layer, gradually causing SAT to fall below SST.

UHPLC ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAH) COMPOUNDS FROM THE SOIL BY QuEChERS AOAC METHOD FROM MANESAR INDUSTRIAL AREA, HARYANA, INDIA

An Ultra-High-Performance Liquid Chromatography (UHPLC) method was developed and validated as per ICH guidelines for the analysis of 16 PAH compounds as per USEPA and various soil samples were analyzed in Manesar located 60 km away from Delhi, capital of India 28.3542° N, 76.9400° E in different seasons. The sampling was done in the industrial areas, agricultural fields, and residential plots all within 10 km radius of the industrial area. In the present study, the QuEChERS method was used for sample preparation, which has shown good recoveries around 80 to 120% The extraction time was only 10 minutes, followed by the UHPLC technique of run time of just 16 minutes. Average PAH concentration in Manesar soil was found highest in the winter session of industrial areas. ∑16 PAH was 141 ppb in the industrial area in winter, 64 ppb in agricultural fields, and 54.7 ppb in residential plots. The lowest PAH levels were observed in the monsoon season. These values are very less if compared to Brazil, UK, Germany, and Korea.