Rural Stations Research Articles

Urbanization effects on intensifying extreme precipitation in the rapidly urbanized Tai Lake Plain in East China

Extreme precipitation (EP) exerts various effects on human life and ecosystems with global warming and regional urbanization. However, the specific contribution of accelerating urbanization to EP changes is less understood. Taking the Tai Lake Plain (TLP) (among the top three most urbanized regions in China) as the study area, this study identified EP changes in frequency and magnitude using Innovative Trend Analysis (ITA), and quantified urbanization impacts on EP innovatively using a dynamical approach for classifying urban and rural stations based on time-varying land use. The results indicated that: (1) From 1966 to 2015, EP is becoming increasingly frequent, intense and persistent, particularly in the northeast and southeast of TLP. Much attention should be paid to the higher risks of flooding or waterlogging especially in big cities (e.g., Shanghai and Hangzhou) in these areas; (2) It was estimated that urbanization induced an average increase of 0.16 days per decade to EP frequency, contributing about 20% to the prolonging trend. Meanwhile, approximately 15% of the intensifying trend for magnitude was attributed to urbanization, i.e., 3.61 units per decade on average; (3) Up to half of the increases of EP risks were attributed to rapid urbanization during 1966–2015, as denoted by positive fraction values (i.e., 0.12–0.52) of attributable risk. Such results reveal the multi-faceted behaviors of EP in relation to time-varying urbanization in TLP region for the first time. They could provide valuable insights in planning urban landscape and mitigating adverse impacts of extreme climate activities at the local scale.

Enlightenment from mitigation of human-perceived heat stress risk in Southwest China during the period 1961–2019

With the effects of climate change, people are increasingly facing human-perceived heat stress (HPHS), which describes the combined effects of high temperature, high humidity, and low surface wind speed. HPHS has a significant impact on industrial and agricultural production, people's lifestyles, and public health. However, the characteristics of HPHS with respect to changes and influencing factors have not been fully investigated using dynamic classification of urban, suburban, and rural stations based on absolute and relative thresholds of seven HPHS indices in Southwest China. The results of this study revealed that, first, during the period 1961–2019, the normal annual and seasonal HPHS values and extreme HPHS days increased significantly, while the extreme HPHS values for the seven HPHS indices decreased. Second, based on the absolute and relative thresholds, the frequency and intensity of the impact of urbanization differed in four regions, and in Yunnan and Guizhou in particular. Different HPHS indices and different dynamic station classification methods result in different estimations of the effects of urbanization on annual and seasonal changes in the regional climate. Therefore, choosing an appropriate dynamic station classification method and considering the applicability of different indices in different seasons in different regions is very important. Third, the Granger causality test shows that the percentage of stations with Granger causality between landscape composition indices and seven extreme HPHS is the highest among all influencing factors. At the same time, boosted regression tree detection also showed that the landscape composition indices had the highest contribution percentage to the seven extreme HPHS. Therefore, rational planning of land-use patterns, especially in relation to urban forest land, grassland, wetland, and water bodies (including vertical landscape composition, configuration planning, and building density and layout) has implications for the realization of the United Nations Sustainable Development Goals (SDGs), in particular SDG 11, Sustainable Cities and Communities.

Spatial and Temporal Variations of Polychlorinated Biphenyls and Organochlorine Pesticides in Snow in Eastern Siberia

This study evaluated the spatial and long-term variations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the snow at 55 industrial, urban, rural, and remote stations in Eastern Siberia, Russia, in 2021 in comparison to data obtained from the 1990s to the 2010s. In 2021, the mean levels of the organochlorine compounds in snow amounted to 76 ng/L ∑PCB36, 5.8 ng/L hexachlorobenzene (HCB), 0.02 ng/L α-hexachlorocyclohexane (HCH), and 1.01 ng/L dichlorodiphenyltrichloroethane (DDT) and its metabolites. The spatial distribution of organochlorines was shown to result from the presence of industrial and urban sources, as well as atmospheric transport. The PCB and HCB temporal distributions from the 1990s to the 2020s were represented as V-shaped curves. The PCB homological patterns show that, in some of the samples, the abundance of lower chlorinated homologues in 2021 is greater than in previous years. Over the last three decades, the HCH and DDT levels have significantly decreased. The relationship between PCBs and suspended particulate matter became stronger with the increase in PCB chlorination levels from lighter to heavier chlorinated congeners. Deposition with wet precipitation in the wintertime provided 3–8% of the annual deposition flux. Massive POP deposition with wet precipitation occurred in May (about 12–18%) and from July to September (60–65%).

On the transition of major pollutant and O3 production regime during Covid-19 lockdowns

Lockdowns enforced amid the pandemic facilitated the evaluation of the impact of emission reductions on air quality and the production regime of O3 under NOx reduction. Analysis of space-time variation of various pollutants (PM10, PM2.5, NOx, CO, O3 and VOC or TNMHC) through the lockdown phases at eight typical stations (Urban/Metro, Rural/high vegetation and coastal) is carried out. It reveals how the major pollutant (PM10 or PM2.5 or O3, or CO) differs from station to station as lockdowns progress depending on geography, land-use pattern and efficacy of lockdown implementation. Among the stations analyzed, Delhi (Chandnichowk), the most polluted (PM10 = 203 μgm−3; O3 = 17.4 ppbv) in pre-lockdown, experienced maximum reduction during the first phase of lockdown in PM2.5 (−47%), NO2 (−40%), CO (−37%) while O3 remained almost the same (2% reduction) to pre-lockdown levels. The least polluted Mahabaleshwar (PM10 = 45 μgm−3; O3 = 54 ppbv) witnessed relatively less reduction in PM2.5 (−2.9%), NO2 (−4.7%), CO (−49%) while O3 increased by 36% to pre-lockdown levels. In rural stations with lots of greenery, O3 is the major pollutant attributed to biogenic VOC emissions from vegetation besides lower NO levels. In other stations, PM2.5 or PM10 is the primary pollutant. At Chennai, Jabalpur, Mahabaleshwar and Goa, the deciding factor of Air Quality Index (AQI) remained unchanged, with reduced values. Particulate matter, PM10 decided AQI for three stations (dust as control component), and PM2.5 decided the same for two but within acceptable limits for stations. Improvement of AQI through control of dust would prove beneficial for Chennai and Patiala; anthropogenic emission control would work for Chandani chowk, Goa and Patiala; emission control of CO is required for Mahabaleshwar and Thiruvanathapuram. Under low VOC/NOx ratio conditions, O3 varies with the ratio, NO/NO2, with a negative (positive) slope indicating VOC-sensitive (NOx-sensitive) regime. Peak O3 isopleths as a function of NOx and VOC depicting distinct patterns suggest that O3 variation is entirely non-linear for a given NOx or VOC.

Temperature and urban heat island effect in Lublin city in Poland under changing climate

This study investigates the characteristics of the temperature regimes at an urban station (Litewski square) in Lublin city in Poland and a nearby rural station (Radawiec), and the Urban Heat Island (UHI) effect in Lublin city. In winter, spring, summer, and autumn at both urban and rural stations frequency distributions of daily minimum (Tmin), and maximum (Tmax) air temperature in 1998–2020 have shifted towards a warmer climate compared to the frequency distributions in 1974–1997. At both stations in 1974–2020, in all seasons, the annual Tmin and Tmax display increasing trends. At Litewski square and Radawiec, Tmax shows increasing trends of 0.083 and 0.088 ºC/year in summer, respectively. This is the largest increase in all four seasons. Furthermore, it is revealed that the heatwaves at both the urban and rural stations have increased in number over time. However, cold waves at both stations show a declining trend. The UHI effect in Lublin city has not increased significantly during 1974–2020. Population in Lublin city has declined over the period 1995–2020, but the population in the surrounding rural counties has increased. It is speculated that this is one of the causes of no clear increase in the UHI intensity. Apart from that, the city’s large green coverage (about 40%) is probably acting as a heating inhibitor. The annual Tmin and Tmax projected by 15 Coupled Model Intercomparison Project Phase 6 (CMIP6) GCMs indicate that the temperature regimes at both urban and rural stations show significant increasing trends during 2015–2100 under the selected SSPs, with the highest increase under high emission scenario (SSP5-8.5) and the lowest increase under the low emission scenario (SSP1-2.6). During 2015–2100, the UHI effect in Lublin city does not show any significant increasing or decreasing trends for the majority of the GCM–SSP combinations.

Observational analyses of a penetrating sea-breeze front in the Beijing-Tianjin-Hebei urban agglomeration

A number of simulation studies show that the sea-breeze fronts (SBFs) that form at the Bohai Bay coast can penetrate far inland through the Beijing-Tianjin-Hebei urban agglomeration (BTH). However, there has been little observational evidence for this claim. Based on dense surface observation networks, we observed a SBF that penetrated 170 km inland from Bohai Bay, interacting with cities in the BTH. The SBF was retarded in urban areas compared to surrounding areas, leading to the front line bending in urban areas. The nocturnal surface air temperature of both urban and rural stations increased temporarily as the SBF passed. Urban roughness effects caused strong updrafts during the passage. Ceilometers observed that the strong updraft of the SBF lifted near-surface aerosols to form sea-breeze heads (SBHs), leading to higher SBHs in urban areas than in rural areas. The uplifted aerosols gradually formed thin aerosol plumes, and produced clouds about four hours after the SBF passed. Our observations will help to improve understanding of the interactions between inland SBFs and cities, and provide a basis for further research on the physical mechanisms of how the inland SBF affects aerosols, clouds, and precipitation in the BTH and elsewhere.

Ionic composition of six-year daily precipitation samples collected at JRC-Ispra (Italy) in relation to synoptic patterns and air mass origin

A six-year dataset of daily precipitation samples collected and analyzed at the rural background station of Joint Research Center (JRC) at Ispra (Italy), was studied in conjunction with synoptic patterns and Concentration Weighted Trajectory (CWT) model in order to identify atmospheric mechanisms and transport pathways affecting the concentrations of eight major inorganic ions: NO3−, Cl−, Na+, Mg2+, Ca2+, SO42−, NH4+ and K+. A Principal Component Analysis (PCA) distributed the studied constituents to three categories reflecting major emission sources: a) Anthropogenic b) Sea salt and c) Crustal. The concentrations of all ions in precipitation samples were negatively correlated with precipitation amounts, however the negative correlations were more enhanced for species having a mainly anthropogenic origin (NO3−, SO42−, NH4+ and K+). The anthropogenic constituents were transported mainly from continental Europe, while the primary role of emissions in the industrialized Po Valley was highlighted from the impact of Eastern airflows on NO3−, SO42−, NH4+ and K+ levels. In addition, a secondary Saharan dust source for SO42− was verified. Sea salt species (Cl−, Na+ and Mg2+) were originated from the Mediterranean Sea, the North Sea, the Baltic Sea, and possibly from the Atlantic through France, while Saharan dust intrusions clearly enhanced the levels of crustal constituents (Ca2+ and Mg2+). The elaboration of a multi-year precipitation dataset for the first time with CWT model, provided new insights regarding the emission sources and transport mechanisms affecting the ionic composition of precipitation samples collected at JRC-Ispra.

Investigation of the Parameters Influencing Baseline Ozone in the Western United States: A Statistical Modeling Approach

Ground-level ozone (O3) is a key atmospheric gas that controls the oxidizing capacity of the atmosphere and has significant health and environmental implications. Due to ongoing reductions in the concentrations of O3 precursors, it is important to assess the variables influencing baseline O3 to inform pollution control strategies. This study uses a statistical model to characterize daily peak 8 h O3 concentrations at the Mount Bachelor Observatory (MBO), a rural mountaintop research station in central Oregon, from 2006–2020. The model was constrained by seven predictive variables: year, day-of-year, relative humidity (RH), aerosol scattering, carbon monoxide (CO), water vapor (WV) mixing ratio, and tropopause pressure. RH, aerosol scattering, CO, and WV mixing ratio were measured at MBO, and tropopause pressure was measured via satellite. For the full 15-year period, the model represents 61% of the variance in daily peak 8 h O3, and all predictive variables have a statistically significant (p < 0.05) impact on daily peak 8 h O3 concentrations. Our results show that daily peak 8 h O3 concentrations at MBO are well-predicted by the model, thereby providing insight into what affects baseline O3 levels at a rural site on the west coast of North America.

Effect of urbanization on the long-term change in pan evaporation: A case study of the Nanpan River Basin in China

Evaporation is a major component of both the surface energy balance and terrestrial water balance. Rapid urban development can change the climate of urban areas, which may have an impact on pan evaporation. In this study, we analyzed the differences in pan evaporation between urban and rural stations, using the Nanpan River Basin of China as the study area. Site pair analysis was conducted using evaporation and socioeconomic data from 25 meteorological and 14 hydrological stations from 1980 to 2016. An urbanization effects indicator, namely EUE, was created to quantify the urbanization effects. Subsequently, a gray relational analysis (GRA) between the urbanization effects indicator and socioeconomic indicators was conducted to identify the effect of socio-economic indicators on urbanization effects. The main results were as follows. (1) During the period 1980–2016, the pan evaporation in the Nanpan River Basin showed a decreasing trend, which was similar in both urban and rural stations, with slopes of −2.87 and −2.89 mm/yr, respectively. (2) After the sudden change in pan evaporation in the Nanpan River Basin in 2000, the slope difference between urban and rural stations increased significantly. The slope of pan evaporation at urban stations was −4.55 mm/yr, whereas that at rural stations was 1.01 mm/yr. The slope difference between urban and rural stations was −5.56 mm/yr, larger than that in 1980–2000 (−0.43 mm/yr). (3) Urbanization influenced the trend and slope of the long-term change in pan evaporation. The rising slope decreased after 2000 in two of the seven cities, and the rising trend changed to a decreasing one in five cities. The difference between the slopes in 2001–2016 and 1980–2000 △E was used as the urbanization effects indicator EUE, and the EUE of all seven cities was<0. (4) The GRA based on the established urbanization effects indicator and urbanization indicators revealed that land use indicators were the factors with the greatest influence on the urbanization effects EUE, and the remaining indicators were social, population, transportation, and national economic indicators. This study is critical important for assessing the long-term changes of pan evaporation and can provide a basis and reference for water resources management in the basin.

Confounding effects of harvesting on urban heat island intensity in a mid-sized city in Brazil

Urban heat island (UHI) studies have traditionally focused on the relative difference between air temperatures measured at an urban area and those at a rural location, taken as a reference. Whereas the influence of urban areas on UHI intensity has been abundantly explored, the impact of the choice of an adequate rural reference location, due to the frequent agricultural use of rural areas, still remains understudied. The issue of climate variability of rural areas is a determining factor for assessing UHI intensity. Brazil is the world's largest sugarcane producer, with a 33% share of the global market. Many mid-sized cities in the Brazilian state of São Paulo are located close to sugarcane fields, which all undergo the sugarcane growth cycle with defined pre-harvest and post-harvest stages. The aim of this study is to understand the interference of seasonal harvesting periods in sugarcane plantations on the development of UHI magnitudes in and around (at suburban locations) Piracicaba, located in the state of São Paulo, Brazil, at 22° 42′ 30“ S and 47° 38’ 01” W and characterized by Köppen-Geiger's Cfa, humid subtropical climate. We deployed a fully-equipped weather station at the site of a sugarcane crop at post- and pre-harvest and a small network of three weather stations provided with air temperature and humidity sensors in the city center and in suburban neighborhoods in Piracicaba. Pre-harvest showed the highest UHI intensities, though not confounding the analysis of intra-urban temperature differentiation patterns. Results stress the relevance of the choice of the baseline rural station in terms of temporal variability related to the sugarcane harvesting cycle.

Quantifying the importance of vehicle ammonia emissions in an urban area of northeastern USA utilizing nitrogen isotopes

Abstract. Atmospheric ammonia (NH3) is a critical component of our atmosphere that contributes to air quality degradation and reactive nitrogen deposition; however, our knowledge of NH3 in urban environments remains limited. Year-long ambient NH3 and related species were measured for concentrations and the nitrogen isotopic compositions (δ15N) of NH3 and particulate ammonium (pNH4+) were measured to understand the temporal sources and chemistry of NH3 in a northeastern US urban environment. We found that urban NH3 and pNH4+ concentrations were elevated compared to regional rural background monitoring stations, with seasonally significant variations. Local and transported sources of NHx (NH3+ pNH4+) were identified using polar bivariate and statistical back trajectory analysis, which suggested the importance of vehicles, volatilization, industry, and stationary fuel combustion emissions. Utilizing a uniquely positive δ15N(NH3) emission source signature from vehicles, a Bayesian stable isotope mixing model (SIMMR) indicates that vehicles contribute 46.8±3.5 % (mean ±1σ) to the annual background level of urban NHx, with a strong seasonal pattern with higher relative contribution during winter (56.4±7.6 %) compared to summer (34.1±5.5 %). The decrease in the relative importance of vehicle emissions during the summer was suggested to be driven by temperature-dependent NH3 emissions from volatilization sources, seasonal fuel-combustion emissions related to energy generation, and change in seasonal transport patterns based on wind direction, back trajectory, and NH3 emission inventory analysis. This work highlights that reducing vehicle NH3 emissions should be considered to improve wintertime air quality in this region.

Links between the concentrations of gaseous pollutants measured in different regions of Estonia.

The factors that determine the concentrations of air pollutants (NO, NO2, SO2, O3), measured in 8 monitoring stations (4 rural background, 3 urban, and 1 industrial) in Estonia, are studied applying the factor analysis. The factor analysis reveals remarkable impact of COVID-19 lockdown, effects caused by dramatic decrease in oil-shale based energy production in Estonia provoked by new socio-economic conditions such as elevated price for CO2 emission quota, differences between rural and urban stations, maritime-continental difference for NO2 and ozone, and specific industrial impact in case of SO2. The multiple regression analysis to predict the ozone concentration in one rural background station at Tahkuse was performed, based on the ozone concentrations measured in other stations and the concentrations of NO, NO2, and CO2, recorded in the same station. It was found that the ozone concentration at Tahkuse is rather well predictable (determination coefficient, i.e., correlation coefficient squared, R2 = 0.714), using only the concentrations from another rural station at Saarejärve that is about 110 km away from Tahkuse. Adding all the available data into the list of regression analysis arguments, the model predictability is improved moderately (determination coefficient R2 = 0.795). Large model residuals above all tend to occur with the values measured and predicted at summer nights. Surprisingly, neither NO nor NO2 concentration measured in the Tahkuse station did appear a good predictor for ozone (R2 = 0.02 and 0.05, respectively), possibly long-range transport of ozone (that has also experienced NO and/or NO2 influence during transport) overrides the local effects of NO and/or NO2.

Comparison of S5P/TROPOMI Inferred NO2 Surface Concentrations with In Situ Measurements over Central Europe

The aim of this paper is to evaluate the surface concentration of nitrogen dioxide (NO2) inferred from the Sentinel-5 Precursor Tropospheric Monitoring Instrument (S5P/TROPOMI) NO2 tropospheric column densities over Central Europe for two time periods, summer 2019 and winter 2019–2020. Simulations of the NO2 tropospheric vertical column densities and surface concentrations from the Long-Term Ozone Simulation–European Operational Smog (LOTOS-EUROS) chemical transport model are also applied in the methodology. More than two hundred in situ air quality monitoring stations, reporting to the European Environment Agency (EEA) air quality database, are used to carry out comparisons with the model simulations and the spaceborne inferred surface concentrations. Stations are separated into seven types (urban traffic, suburban traffic, urban background, suburban background, rural background, suburban industrial and rural industrial) in order to examine the strengths and shortcomings of the different air quality markers, namely the NO2 vertical column densities and NO2 surface concentrations. S5P/TROPOMI NO2 surface concentrations are inferred by multiplying the fraction of the satellite and model NO2 vertical column densities with the model surface concentrations. The estimated inferred TROPOMI NO2 surface concentrations are examined further with the altering of three influencing factors: the model vertical leveling scheme, the versions of the TROPOMI NO2 data and the air mass factors applied to the satellite and model NO2 vertical column densities. Overall, the inferred TROPOMI NO2 surface concentrations show a better correlation with the in situ measurements for both time periods and all station types, especially for the industrial stations (R &gt; 0.6) in winter. The calculated correlation for background stations is moderate for both periods (R~0.5 in summer and R &gt; 0.5 in winter), whereas for traffic stations it improves in the winter (from 0.20 to 0.50). After the implementation of the air mass factors from the local model, the bias is significantly reduced for most of the station types, especially in winter for the background stations, ranging from +0.49% for the urban background to +10.37% for the rural background stations. The mean relative bias in winter between the inferred S5P/TROPOMI NO2 surface concentrations and the ground-based measurements for industrial stations is about −15%, whereas for traffic urban stations it is approximately −25%. In summer, biases are generally higher for all station types, especially for the traffic stations (~−75%), ranging from −54% to −30% for the background and industrial stations.

Influence of Urbanization on Spatio-Temporal Characteristics of Extreme Hourly Precipitation in Shenyang

Understanding changes in extreme hourly precipitation is critical to urban planners for building more sustainable and resilient cities. In this study, we use satellite nighttime light data, urban land area data, population, and economic data to objectively classify urban and rural stations. Based on the hourly precipitation data from national meteorological stations in 1974–2020 and from regional automatic weather stations in 2005–2020 in Shenyang (China), the spatio-temporal distribution characteristics of the thresholds, maximums, intensities, and frequencies of extreme hourly precipitation (ExHP) in urban and rural areas are analyzed and compared. The results show that the large-value centers of ExHP thresholds, maximums, and intensities are mainly concentrated in urban areas. Both the frequency and intensity of ExHP at urban stations are obviously larger than those at rural stations, and the peaks mainly appear at night for stations of both two types. From 1974 to 2020, the average frequency and intensity of ExHP at urban stations both show increasing trends, with the increasing rate being much higher than those at rural stations. In terms of temporal variation, precipitation events of the abrupt type are the most frequent, accounting for 48.6% of the total, followed by the growing type (42.7%) and continuous type (8.7%). ExHP events of the abrupt type are mostly concentrated in Kangping County and Faku County of Northern Shenyang, but rarely occur in Xinmin City. ExHP events of the growing type are mainly found in Xinmin City and the municipal district of Shenyang. For urban stations, the ExHP frequency decreases in the early stage of urbanization, while increasing evidently during the rapid urbanization stage. However, the situation is just the opposite for rural stations. This indicates that the rapid urbanization in Shenyang has a certain impact on the increase in ExHP.

The Impact of Urbanization on Extreme Climate Indices in the Yangtze River Economic Belt, China

Urbanization has been proven to be a critical factor in modifying local or regional climate characteristics. This research aims to examine the impact of urbanization on extreme climate indices in the Yangtze River Economic Belt (YREB), China, by using meteorological observation data from 2000 to 2019. Three main steps are involved. First, a clustered threshold method based on remote-sensing nighttime light data is used to extract urban built-up areas, and urban and rural meteorological stations can be identified based on the boundary of urban built-up areas. Nonparametric statistical tests, namely, the Mann–Kendall test and Sen’s slope, are then applied to measure the trend characteristics of extreme climate indices. Finally, the urbanization contribution rate is employed to quantify the impact of urbanization on extreme climate indices. The results indicate that urbanization has a more serious impact on extreme temperature indices than on extreme precipitation indices in the YREB. For extreme temperature indices, urbanization generally causes more (less) frequent occurrence of warm (cold) events. The impact of urbanization on different extreme temperature indices has heterogeneous characteristics, including the difference in contamination levels and spatial variation of the impacted cities. For extreme precipitation indices, only a few cities impacted by urbanization are detected, but among these cities, urbanization contributes to increasing the trend of all indices.

Impact of Shale Gas Exploration and Exploitation Activities on the Quality of Ambient Air—The Case Study of Wysin, Poland

The continuous two-year monitoring of a set of air pollutants, as well as gases directly related to shale gas exploration processes (methane, non-methane hydrocarbons, carbon dioxide), was carried out at Stary Wiec village in the vicinity (1100 m) of the shale gas wells area in Wysin (Pomeranian voivodeship, north of Poland), covering the stages of preparation, drilling, hydrofracturing and closing of wells. The results of analysis of air pollution data from Stary Wiec and nearby urban and rural stations, over the period 2012–2017 (starting three years before preparations for hydraulic fracturing) indicated that Stary Wiec represents a clean rural environment with an average concentration of nitrogen oxides, carbon monoxide and particulate matter that is one of the lowest in the Pomeranian region. The aim of this study was to explore the range of potential impact of shale gas exploration on local ambient air quality. Analysis of dependence of the concentration level of pollutants on the wind direction indicated that during the drilling period, when the air was coming directly from the area of the wells, nitrogen oxide concentration increased by 13%. Increases of concentration during the hydro-fracturing period, recorded at the Stary Wiec station, were equal to 108%, 21%, 18%, 12%, 7%, 4%, 1% for nitrogen oxide, non-methane hydrocarbons, carbon monoxide, nitrogen dioxide, particulate matter, carbon dioxide and methane. The results of one-minute concentration values for the period 1–4 September 2016 showed a series of short peaks up to 7.45 ppm for methane and up to 3.03 ppm for non-methane hydrocarbons, being probably the result of operations carried out at the area of the wells.

Design of Hydraulic System of Microcomputer Governor for Small Turbine

Taking a power station as an example and according to the technical and performance requirements of the turbine governor in small rural hydropower stations, a hydraulic station with high oil pressure is designed by adopting a highly reliable general PLC as the control device and using standardized hydraulic components; Taking into account requirements for regulating performance under the conditions of automatic regulation, manual regulation and emergency shutdown, and the reliability requirements, the hydraulic control circuit with automatic adjustment, manual adjustment and emergency stop is designed to avoid possible problems of hydraulic system by taking effective measures. The product based on the design have been developed and put into production to meet the requirements of industry standard and its application with good effect can be further promoted.

Quantification of the urbanization impacts on solar dimming and brightening over China

Metropolis’ contribution (anthropogenic aerosols) to solar dimming and brightening remains a hot topic of special concern over the past several decades. However, urbanization effects on surface incident solar radiation (R s) have not been comprehensively investigated. In this study, the urbanization effects on solar dimming and brightening were addressed using the densely distributed reconstructed R s data at 375 stations and 92 urban–rural station pairs over the time period of 1960–2019 in China. The results indicate that the impacts of urbanization on the monthly mean R s is 0.86 ± 7.99 W m−2 during the study period, while the impact is 0.90 ± 8.30 W m−2 and 0.82 ± 8.26 W m−2 for the solar dimming (1960–1992) and brightening (1992–2019) phase, respectively. The urbanization effects on the trend of R s is −0.39 and 0.16 W m−2 per decade during dimming and brightening, respectively. It also found that urbanization effects on R s trend differs strikingly in magnitudes for specific regions in China. Generally, urbanization speeds up China’s dimming in the dimming phase and slows down China’s brightening in the brightening phase.

Observation-based analysis of ozone production sensitivity for two persistent ozone episodes in Guangdong, China

Abstract. An observation-based method (OBM) is developed to investigate the sensitivity of ozone formation to precursors during two persistent elevated ozone episodes observed at 77 stations in Guangdong. Average OH concentrations derived at the 77 stations between 08:00 and 13:00 local time stay within a narrow range of 2.5×106 to 5.5×106 cm−3 with a weak dependence on the NOx. These values are in good agreement with OH values observed at a rural station in the Pearl River Delta (PRD). They also agree well with a box model constrained by the ambient conditions observed during the two episodes. The OBM has been used to evaluate the ozone production efficiency, ε(NOx or volatile organic compound, VOC), defined as the number of O3 molecules produced per molecule of NOx (or VOC) oxidized. Average values of ε(NOx) and ε(VOC) determined by the OBM are 3.0 and 2.1 ppb ppb−1, respectively, and both compared well with values in previous studies. Approximately 67 % of the station days exhibit ozone formation sensitivity to NOx, and approximately 20 % of the station days are in the transitional regime sensitive to both NOx and VOC, and only approximately 13 % of the station days are sensitive to VOC. These results are in semi-quantitative agreement with the ozone formation sensitivity calculated by the box model constrained by ambient conditions observed during the two episodes. However, our OBM results differ from those of most previous investigations, which suggested that limiting the emission of VOC rather than NOx would be more effective in reducing ozone reduction in Guangdong.

The victimisation of farms in Ireland: fear of crime, social isolation and crime prevention

This paper explores farmer’s experiences of crime and their attitudes towards crime prevention in one rural hinterland. Farmer’s attitudes about safety and crime present a dichotomy: fear of victimisation was relatively high, yet few participants reported having been victimised, and there was a perception that agricultural crime was high in Ireland but low in their locality. Feelings of insecurity were partly influenced by the closure of rural Garda stations and uneven distribution of information technology. Participants were most concerned with theft of small machinery, violent coercion connected to fraudulent work, illegal dumping and trespassing, rather than thefts of expensive machinery and livestock. Participants reported being unable to afford some crime prevention measures and/or having insufficient time to implement them. The paper concludes by highlighting the relevance of Farrell and Tilley’s (2020) concept of elegant security to farm crime and discussing the role of community policing.