Season In China Research Articles

Attribution of meteorological, hydrological and agricultural drought propagation in different climatic regions of China

Drought propagation describes the changes in a drought signal as it moves from one major type of drought to another. It is important to investigate the propagation among meteorological, agricultural and hydrological drought, as well as their major impacting factors, to improve understanding of the drought propagation relationship, monitor agricultural drought and reduce crop losses. This study presents the first exploration of the interplay between multiple droughts among different climate zones and seasons in China. The standardized precipitation evapotranspiration index (SPEI), standardized runoff index (SRI) and self-calibrating Palmer drought severity index (scPDSI) were used to represent meteorological, agricultural and hydrological drought, respectively. The Pearson correlation coefficient was used to analyze the propagation relationships among different droughts and identify the most sensitive season for drought propagation. The Lindeman–Merenda–Gold (LMG) method was used to quantify the relative importance of PRE (precipitation), PET (potential evapotranspiration) and SM (soil moisture) to hydrological and agricultural drought. The propagation from meteorological to agricultural drought was prominent in different seasons at the annual scale over China. In general, the propagation relationship from agricultural to hydrological drought was weaker than that from meteorological to agricultural drought. In Northern China (arid and semi-arid areas), there was a stronger propagation relationship from agricultural to hydrological drought in summer and autumn than in spring. There was also stronger propagation from agricultural to hydrological drought in eastern China than in western China. Different climate regions had different major factors driving hydrological drought because of the different climate characteristics. However, SM was generally the most important driving factor for agricultural drought in all climate regions. Mulching plastic film might be an effective and feasible method to reduce PET from soil evaporation in sub-regions that apply high irrigation levels. These findings may also be applied to strengthen the study of artificial regulation of water resources, which could be an approach to reducing crop losses from drought.

A Machine Learning Method for Predicting Vegetation Indices in China

To forecast the terrestrial carbon cycle and monitor food security, vegetation growth must be accurately predicted; however, current process-based ecosystem and crop-growth models are limited in their effectiveness. This study developed a machine learning model using the extreme gradient boosting method to predict vegetation growth throughout the growing season in China from 2001 to 2018. The model used satellite-derived vegetation data for the first month of each growing season, CO2 concentration, and several meteorological factors as data sources for the explanatory variables. Results showed that the model could reproduce the spatiotemporal distribution of vegetation growth as represented by the satellite-derived normalized difference vegetation index (NDVI). The predictive error for the growing season NDVI was less than 5% for more than 98% of vegetated areas in China; the model represented seasonal variations in NDVI well. The coefficient of determination (R2) between the monthly observed and predicted NDVI was 0.83, and more than 69% of vegetated areas had an R2 > 0.8. The effectiveness of the model was examined for a severe drought year (2009), and results showed that the model could reproduce the spatiotemporal distribution of NDVI even under extreme conditions. This model provides an alternative method for predicting vegetation growth and has great potential for monitoring vegetation dynamics and crop growth.

English

As there is a frequent occurrence of haze during the heating season in China’s severely cold regions, the environmental parameters of the three types of buildings in Daqing were monitored to investigate the concentration and exposure level of particulate matter 2.5 (PM2.5). The short-term exposure levels of PM2.5for people of different ages and genders were analyzed. The composition and diversity of bacteria were analyzed using 16S rDNA technology. The results showed that the average PM2.5 concentrations of office buildings were higher than that of residential buildings, which was then higher than that of teaching buildings in Daqing. The exposure level of adults in urban areas was 12.0% higher than those in rural areas. Children had almost the same overall exposure. The potential comprehensive dose and its average dose for adults in urban areas were higher than those in rural areas, and the number of males was higher than females. The risk of exposure increased with age and was higher for males than females. Among the three types of buildings in Daqing, the main bacteria were Proteobacteria, Bacteroidetes and Firmicutes. In the same type of buildings, the total number of bacteria was higher outdoors than indoors and the alpha diversity of bacteria was higher outdoors than indoors. © 2021 Friends Science Publishers

Improved influenza vaccination coverage among health-care workers: evidence from a web-based survey in China, 2019/2020 season

ABSTRACT To understand influenza vaccination and its correlates among health-careworkers (HCWs) during the 2019/2020 season in China, we used a self-administeredelectronic questionnaire to collect information on demographics, occupational characteristics, influenza vaccination status and access to free vaccination on the “Breath Circles”, a Chinese media platform for respiratory medical professionals. The reported influenza vaccine coverage among HCWs during this season was 67%, with more HCWs in a workplace with free vaccination than those with no free vaccination (79% vs.34%,p < .001). The influenza vaccine coverage among HCWs who were required or encouraged to get vaccinated by the workplace was significantly higher than that without any intervention measures (80% & 70 vs.39%,p < .001). The vaccine coverage in the workplaces with free and required vaccination simultaneously was highest compared to that with neither free vaccination nor any intervention measures (OR = 14.86, 95% CI: 10.93–20.20). The influenza vaccination coverage of HCWs in high-riskdepartments was significantly higher than that of other departments (70% vs.58%,p =.023). HCWs’ vaccine coverage was related to personal opinions and attitudes toward influenza or influenza vaccines, as well as other constraints such as availability of influenza vaccines, workplace regulations, and access to free vaccines.

Initiation of an Elevated Mesoscale Convective System With the Influence of Complex Terrain During Meiyu Season

AbstractA mesoscale convective system (MCS) was initiated on the lee side of the Wuling Mountain in central‐east China in the late afternoon (1700 LT) on June 27, 2016, and led to an early morning precipitation peak. We investigated the convective initiation (CI) mechanism of this MCS using radars and automatic weather station observations, WRF model simulation, and analysis from the radar data assimilation system Variational Doppler Radar Analysis System. It was found that the convection initiation was elevated as indicated by an elevated convergence zone and updraft located above 1,625 m from the ground. A zero convective inhibition layer was located at 850 hPa, over a stable boundary layer (BL) resulting from the daytime rainfall in the plain region, and provided a favorable condition for the elevated CI. Our study suggested that the transition of mountain‐plain thermal wind near sunset was the trigger for the convective initiation. An early afternoon mountain‐plain thermal circulation was disrupted when the east‐facing lee side slope was in the shadow of sunshine after 4 p.m. As a result, a local‐scale northwest downslope wind accelerated and led to a downstream convergence above the stable BL, where the elevated convection was initiated near 1,625 m above ground level. By combining the model simulation, the analysis from data assimilation, and the observations, this study is the first to provide a detailed analysis of CI mechanism of elevated convection in a complex topography region during the Meiyu season in China.

Impacts of Spectral Nudging Parameters on Dynamical Downscaling in Summer over Mainland China

Spectral nudging is an important method of improving the effectiveness of dynamical downscaling in the Weather Research and Forecasting model (WRF). However, spectral nudging is sensitive to nudging parameters, and most related research has typically adopted the default nudging schemes. Summer is the rainy season in China. Both typhoons and heavy rains occur in summer. It is therefore significant to discuss the optimal nudging parameter settings to achieve better summer climate simulations over mainland China. In this study, we analyzed the impacts of various nudged variables and their cut-off wavelengths on the downscaling ability by simulating the summer climate over mainland China in 2009 and 2010. The results showed that nudging the horizontal wind or potential temperature had a significant effect on the simulation of nearly all conventional meteorological fields, and that nudging the geopotential height affected mainly precipitation. The suitable cut-off wavelengths were 500 or 1000 km for wind, 1000-2000 km for potential temperature and 1000 km for geopotential height. Nudging all variables had obvious advantages over nudging the wind, potential temperature or geopotential height individually in nearly all subregions. The appropriate cut-off wavelength was 500-1500 km when all variables were nudged. Overall, nudging all three variables with 1000 km cut-off wavelength is recommended for dynamical downscaling in summer over mainland China.

Incidence of community-acquired pneumonia in urban China: A national population-based study

BackgroundCommunity-acquired pneumonia (CAP) is one of the major global health problems worldwide. However, the epidemiological information of CAP is limited in China. This study aimed to estimate the incidence rate of CAP and describe the epidemiologic characteristics among the Chinese population. MethodsWe conducted a retrospective analysis of CAP incidence using the Chinese Urban Basic Medical Insurance database of 23 provinces in 2016, which covered 427.52 million urban beneficiaries of all age groups in Mainland China. CAP episodes were identified using a diagnosis-term-derived algorithm, and multiple CAP records of one single person within 90 continuous days were considered as one single episode. The incidence rates were calculated and described by sex, age, region, and season. ResultsA total of 1.42 million patients were identified as having one or more CAP episodes, and finally a sum of 1.48 million CAP episodes were counted. The overall incidence of CAP was 7.13 (95% CI: 6.11–8.15) per 1000 person-years, in males 7.32 (95% CI: 6.28–8.35) and females 6.93 (95% CI: 5.92–7.94) per 1000 person-years, respectively. The incidence varied by age with a U-shaped curve peaking in children aged < 5 years old [65.80 (95% CI: 62.52–69.08)] and elderly population aged ≥ 80 years old [14.98 (95% CI: 13.63–16.34)]. The incidence varied markedly by regions. Furthermore, the rate showed a clear seasonal trend, which peaked in spring, decreased in summer and autumn, and re-ascended in winter. ConclusionThis study reveals a relatively high level of CAP incidence in China. These findings provide baseline data for establishing effective prevention strategies, targeted at susceptible populations, regions, and seasons in China.

2011-2019年中国B型流感季节性、年龄特征和疫苗匹配度分析

Objective: To analyze the seasonality, age distribution of influenza B cases and matching degree of influenza B vaccine in China from 2011 to 2019, and provide evidences for the future surveillance, estimation of disease burden of influenza B, application of quadrivalent vaccines, and development of vaccine strategies. Methods: The epidemiological and virological surveillance data of influenza B from week 14 of 2011 to week 13 of 2019 obtained from National Influenza Surveillance Network were used to draw hot spot maps and conduct descriptive statistics to analyze the seasonality and age distribution of influenza B cases. The published antigenicity analysis results from the China Weekly Influenza Report were used to analyze the matching degree between the trivalent vaccine strain and the circulating influenza B strains. Results: From 2011 to 2019, the incidence of influenza B showed obvious seasonal characteristics, and influenza B virus co-circulated with influenza A virus in six winter-spring seasons, and influenza B virus/Victoria and Yamagata lineages circulated alternately. In some southern provinces, two lineages co-circulated in some southern areas in certain years. The age distribution of influenza B cases was double-peaked, and both lineages had the highest positive rate in age-group 5-15 years, with peaks at age of 10 years; B/Victoria virus had a sub-peak in age-group 25-35 years; B/Yamagata virus had a sub-peak in age-group 55-65 years. Trivalent influenza vaccine strain and influenza B epidemic strains mismatched in 2015-2016 and 2017-2018 seasons, matched in 2011-2012, 2012-2013, 2013-2014, 2014-2015 and 2016-2017 seasons, and moderately matched in 2018-2019 season, but reactivity was low. Conclusions: Influenza B mainly occurred in winter-spring season in China, and its intensity was lower than that of influenza A. There was a difference in the age distribution of the cases among different virus strains. Trivalent influenza vaccine strains and influenza B epidemic strains mismatched in several seasons. It is crucial to conduct continuous surveillance of influenza B and disease burden evaluation, improve vaccine immunization strategy, increase influenza vaccination rate to reduce the harm of influenza B in high-risk groups.

Research on key technology and application of flexibility transformation of heating unit to improve clean energy consumption capacity

The electric regulation capacity of heating units has been constantly improving due to the promotion of the heating units? flexibility transformation. This improvement has effectively alleviated the long remained serious wind and light abandonment phenomena in the heating season in China. In this paper, we discussed the key technologies of the low pressure zero output heating mode and bypass heating mode, both of which are widely used in thermo-electric decoupling. Moreover, the coupling transformation of the two heating modes has been successfully realized in a heating unit. The electric regulation capacity of the unit has been greatly improved, from 18.6% before the transformation to 66.7%, and the minimum technical output has been also reduced to 14.2% THA. After the transformation, the unit now is able to provide several heating modes with its operational flexibility greatly improved. By comparing the economical efficiency of these heating modes, we obtained the operation mode with the lowest heat rate. This transformation mode provides a huge grid space for the consumption of clean energy, so it is of positive reference value and exemplary significance in implementing the flexibility transformation of heating units.

Possible role of Southern Hemispheric sea ice in the variability of West China autumn rain

West China Autumn Rain (WCAR), the last rainy season in China associated with the East Asian summer monsoon, is prone to flooding and secondary disasters and has profound impacts on the economic society. Thus, it is of great interest to understand its variability. Through an analysis with gridded rainfall data and reanalysis data, this study reveals that the variability of WCAR is positively correlated to the boreal summer (austral winter) sea ice concentration (SIC) in the Southern Indian and Pacific Ocean basins. Such a relationship is supported by the SIC-related changes in atmospheric circulations and water vapor transport. Corresponding to a high summer SIC, both the Lake Balkhash trough and the Asian low pressure are deepened, the East Asian jet shifts northward, and the water vapor transport to West China is enhanced during the boreal autumn, providing a favorable background for the increase of WCAR, and vice versa. The potential mechanism of how the boreal summer SIC affects the autumn atmospheric situation is further investigated. Results show that the atmospheric circulation in the high latitudes of the Southern Hemisphere possesses a seasonal persistence from the boreal summer to autumn due to the sea ice persistence. Thus, the boreal summer SIC-related anomalies in the upper-tropospheric winds over the Southern Indian and Pacific Ocean basins can persist to the following autumn and subsequently exert substantial influences on the Eurasian atmospheric circulations via two meridional teleconnections. The counterpart in the lower troposphere contributes to the water vapor transport toward West China. Certainly, this candidate mechanism is a preliminary explanation, and other processes may also act in their linkage.

Peach volatile emission and attractiveness of different host plant volatiles blends to Cydia molesta in adjacent peach and pear orchards

The oriental fruit moth (OFM), Cydia (= Grapholitha) molesta, is a highly damaging pest; peaches are its primary host, and pears serve as post-peach secondary hosts during the late season in China. We collected volatiles from detached peach shoots and fruits, and identified them with gas chromatography–mass spectrometry (GC–MS). Antennally active compounds were identified by gas chromatography-electroantennogram detection (GC-EAD), and these were further tested in the laboratory and field. We detected consistent electroantennographic activity was for ten compounds. Significantly more C. molesta females were caught with a mixture of female EAD-active compounds identified from the detached matured peach fruits (nonanal, butyl acetate, 3-methylbutyl acetate, hexyl acetate, (Z)-3-hexenyl acetate, linalool and farnesene) than other mixtures mimicking the volatile profile from detached matured fruits or shoots. We identified a new GC-EAD active mixture from intact peach shoots composed of nonanal, (Z)-3-hexenyl acetate, (E)-β-ocimene, and 6-methyl-5-hepten-2-one. In the field test, the background odour of orchards could affect trap catches, and two peach-derived blends together with two previously known pear-derived blends were proven to be able to monitor the seasonal OFM population dispersal in adjacent orchards. These host plant blends will be effective for further designing candidate attractants for season-long C. molesta population dynamic monitoring.

Modern urbanization has reshaped the bacterial microbiome profiles of house dust in domestic environments

BackgroundThe prevalence of allergy and other common chronic diseases is higher in developed than developing countries, and higher in urban than rural regions. Urbanization through its modification of environmental microbiomes may play a predominant role in the development of these conditions. However, no studies have been conducted to compare the microbiome in house dust among areas with different urbanization levels. MethodsHouse dust from Xinxiang rural area (XR, n = 74), Xinxiang urban area (XU, n = 33), and Zhengzhou urban area (ZU, n = 32) in central China, and from Australia (AU, n = 58 [with pets AUP, n = 15, without pets AUNP, n = 43]) were collected during a summer season in China and Australia. High-throughput sequencing of 16S rDNA was employed to profile house dust bacterial communities. ResultsSettled dust collected in China was dominant with 2 bacterial phyla: Proteobacteria and Actinobacteria, while floor dust collected in Australia had a higher proportion of phylum Proteobacteria, Firmicutes, and Actinobacteria. XR dust samples presented higher bacterial richness and diversity compared with XU or ZU samples. Urbanization level (r2 = 0.741 P < 0.001) had a significant correlation with the distribution of house dust bacterial community. At the genus level, there was a positive correlation (r coefficient > 0.5) between urbanization level and bacterial genera Streptococcus, Bartonella, Staphylococcus, Pseudomonas, Acinetobacter, Bacteroides, Corynebacterium_1,and Enhydrobacter and a negative correlation (r coefficient < −0.5) with Rhodanobacter. ConclusionThere was a significant difference in house dust microbiota among different urbanization areas. The areas with a lower urbanization level presented higher dust-borne bacterial richness and diversity. Modern urbanization has a significant influence on the bacterial microbiome profiles of indoor dust.

Size-differentiated patterns of exposure to submicron particulate matter across regions and seasons in China

Abstract Air pollution in China has reached unprecedented levels due to rapid economic and industrial development. More than 90% of Chinese population experience higher health risks attributable to ambient fine particulate matter (PM2.5) exposure. Although evidence suggests that particle size may be an effect modifier on PM2.5-related health risks, few studies have explored this due to lack of size-resolved exposure data. In this study, we derive size-resolved particle effective radius of PM2.5 using theoretical relationships between aerosol microphysical characteristics and satellite optical measurements to explore the spatial variability and population exposure to ambient particle size. Applying this method to China in 2017, we observed annual mean effective radii between 0.3 and 1.3 μm with a mean average error of 0.1 μm. We find that 1% or less of the Chinese population was exposed to annual PM2.5 concentrations less than 10 μg/m3 and a mean particle effective radius greater than 0.7 μm (i.e. aerodynamic diameter of PM1). Spatially, the Centre economic region had the highest annual-mean PM2.5 exposures, where 90% of the population was exposed to concentrations higher than 50 μg/m3 and 98% was exposed to particles with mean radius below 0.5 μm. Temporally, although the highest PM2.5 concentrations were more likely to occur in winter, summertime was the season during which the highest percentage of the national population (86%) lived in the regions in which the fine fraction had the smallest mean particle radii (

Occurrence, Antimicrobial Resistance Patterns, and Genetic Characterization of Staphylococcus aureus Isolated from Raw Milk in the Dairy Farms over Two Seasons in China.

This study investigated the occurrence and resistance rates of Staphylococcus aureus strains isolated from raw milk in the dairy farms over two seasons (spring and autumn) and across four regions that included 11 provinces in China. In total, 750 raw milk samples from the 405 dairy farms were collected. Fifteen antimicrobial agents were tested for antimicrobial resistance via disk diffusion tests, and PCR tests were performed to identify drug resistance genes of S. aureus isolates. Out of 750 samples, 276 (36.8%) were positive for S. aureus, with 150 (41.1%) being positive in spring and 126 (32.7%) being positive in autumn. The occurrence rate of S. aureus in northeastern China (45%) was higher than that in western China (33%) and southern China (31.9%), respectively, and the rate significantly (p < 0.05) differed from those of western China and southern China. Of 276 isolates, 261 (94.6%) strains were resistant to more than 1 antimicrobial drug, and 193 (69.9%) strains were multidrug resistant. The blaZ (46.3%), dfrG (35.5%), and tetM (27.2%) genes were detected at a high frequency in the S. aureus strains. Our data revealed a variation (p < 0.05) in the resistance patterns in the different regions and across the two seasons. The occurrence and drug resistance rates of S. aureus isolated from raw milk obtained from dairy farms may still cause severe problems in China.

Effects of Prior Influenza Exposure on Immunogenicity of Influenza Vaccine

BackgroundIn this study, we investigated the effects of prior influenza exposure on vaccine-elicited humor immune responses to circulating influenza variants. MethodWe randomly selected 360 participants in previous clinical trials stratified by age. Blood samples were collected and tested by hemagglutination-inhibition tests during the 2015–2016 influenza seasons in China. The antigenic map was plotted and antigenic distance was calculated. ResultsSubjects with H1-priming had higher cross-reactive antibodies titers against A/JiangsuTinghu/11019/2015(H3N2) compared with subjects with B-priming did (Padjusted = .038). Subjects with H1-priming also had higher cross-reactive antibodies titers against A/Jiangsu Qinhuai/11059/2015(H3N2) than subjects with both H1 and B priming (Padjusted = .036). Nevertheless, subjects with no H1 and B-priming had higher cross-reactive antibodies titers against A/Jiangsu Qinhuai/11059/2015(H3N2) than subjects with both H1 and B priming (Padjusted = .012). Antigenic distance was well matched with serological results. Moeover, age-specific differences in human postvaccination responses against the identical circulating strain was noted. In addition, children had the most cross-reactive response to both H3N2 and B-yamagata subtypes. ConclusionsOur results suggest that prior exposure to H1 or B influenza virus may influence cross-reactivity of H3-specific postvaccination responses and consequently could influence the vaccine effectiveness. Our findings also support that there are age-specific differences in human postvaccination responses.

Characteristics of hazardous chemical accidents during hot season in China from 1989 to 2019: A statistical investigation

Because high temperature is one of the main causes of hazardous chemical accidents, these accidents frequently occur in China during hot season (from June to September). Understanding the historical accidents is important for accident prevention and risk mitigation. However, presently, no statistical analysis on the characteristics of China’s hazardous chemical accidents that occurred during hot season is available. Thus, by utilising data from official sources, a statistical investigation on 76 serious hazardous chemical accidents that occurred during hot season in China (1989–2019) was performed in terms of seven aspects: region where the accident occurred, type of accident, types of hazardous chemicals, links of occurrence, size of enterprises, direct cause, and period when the accident occurred. Moreover, according to the statistical results, this paper proposes some potential countermeasures and suggestions to prevent hazardous chemical accidents during hot season in China. This study can provide useful information for preventing hazardous chemical accidents and strengthening preventive measures in chemical plants during hot season in China and in other countries.

Comparison of Aedes albopictus Monitoring Methods and Dengue Risk Assessment in Central China

Dengue fever has been attracting more attention in recent years. Dengue fever is mainly transmitted to humans by the Aedes albopictus mosquito and disease patterns are influenced by its wide distribution and high density during the summer season in China. Dengue epidemics in central China previously occurred exclusively in rural areas, while these recent outbreaks mostly occurred in urban areas in southern China. Until now, the presence of Aedes Albopictus in central China has been scarcely acknowledged. This study is a survey of Aedes and attempts to clarify this new distribution pattern using the Breteau Index (BI) method and a polylactic-glycolic acid (PLGA) copolymer mosquito trap simultaneously in urban and rural areas. The BI can provide a direct value on Aedes density compared to CI. Rural areas are at a higher risk for dengue compared to urban areas in central China. Our findings provide a basis for the prevention and control of dengue vectors, as well as providing information for control strategies for other infectious diseases transmitted by Aedes mosquitoes. Vector control strategy related to the management of diseases transmitted by Aedes should be based on the distribution patterns of different vector species, particularly in the rural environments in central China.

Temporal Pattern Analysis of Local Rainstorm Events in China During the Flood Season Based on Time Series Clustering

Similar to the rainfall depth, duration and intensity, the temporal pattern is also an important characteristic of rainstorm events. Studies have shown that temporal patterns will influence runoff modelling, flash flood warning thresholds as well as urban and infrastructure flood inundation simulations. In this study, a time series clustering method using dynamic time warping (DTW) as similarity measurement criteria is proposed to analyze rainfall temporal patterns. Compared with the existing approaches, it can better reflect the real rainfall processes. Based on this novel method, five representative temporal patterns were extracted from 13,299 rainstorm events during the flood season in China. Through the analysis of their statistical characteristics, the disaster-causing risks of each temporal pattern were compared. Furthermore, we found that for rainstorm events whose durations are less than 24 h, the rainfall is mainly concentrated in 3 to 6 h, which proposes higher requirements for the design of flood control and drainage projects compared with those using average intensities of 12 or 24 h as design standards. Finally, through regional analysis, we found that the rainfall depth, intensity and peak value are affected by the macroclimate. However, the temporal patterns are not strongly related to the macroclimate but are more likely to be affected by the local climate and topography, which needs further studies at smaller scales.

Assessment of the radiation effect of aerosols on maize production in China

With the recent increases in atmosphere aerosol concentration, its impact on agriculture in China is of considerable concern for scientific community. In this study, the effects that aerosols have on radiation and consequently the production of maize in China were investigated from 2002 to 2014 using the AErosol RObotic NETwork (AERONET) data, Second Simulation of a Satellite Signal in the Solar Spectrum radiative transfer (6S) model, and Agricultural Production Systems sIMulator (APSIM) model. Ten stations in the maize planting areas including Beijing, Xianghe, Taihu, Nanjing, Shanghai, Hefei, Baotou, Lanzhou, Qinghaihu, and Xuzhou stations were selected. The results showed that the APSIM-maize model, which was further calibrated, was able to simulate the interactions between maize and the climatic constraints in the maize planting areas of China. Our results indicated that aerosols obviously reduced the amount of solar radiation reaching the surface during the maize growing season in China. We also found that the aerosols have negative effects on both biomass and yield of maize in China at ten stations. The average annual maize biomass during the maize growing season from 2002 to 2014 decreased by 23.70%. The average yield of maize from 2002 to 2014 decreased by 15.10%. However, the influence of aerosol on different varieties of maize varied. We found the aerosols had greater negative impacts on summer maize than on spring maize. For spring maize, the average biomass and yield from 2002 to 2014 decreased by 10.36% and 5.16%, respectively. However, as for the summer maize, the average biomass and yield from 2002 to 2014 were reduced by 19.72% and 20.56%, respectively. Our findings can provide a useful method for estimating the effect of aerosols on crops at the national level, supporting local agricultural production in coping with the ongoing climate change.

Impacts of climate change, population growth, and urbanization on future population exposure to long-term temperature change during the warm season in China.

Climate change is anticipated to raise overall temperatures in the twenty-first century and is likely to intensify population exposure to heat during the warm season and, as a result, increase the risk of heat-related illnesses and deaths. While earlier studies of heat exposure and related health impacts generally focused on the acute effects of short-term exposure indicated by high daily temperature or several days of very hot weather, recent research has suggested that small changes in seasonal average temperature over a long period of time is likely to pose significant health risk as well. Using downscaled climate projections under three Representative Concentration Pathways emission scenarios, high-spatial-resolution population data, and the latest population projections by the United Nations, we aim at projecting future changes in long-term population exposure to summer heat across China in the mid- and late-twenty-first century resulting from global climate change. As the impacts of population growth are often overlooked in projecting future changes in heat exposure, we estimated changes in population-weighted average temperature in the warmest quarter over two future 20-year time periods and compared them with changes in temperature only. Our analysis shows that, nationally, population-weighted average temperature in the warmest quarter is projected to increase by 2.2°C relative to the current situation in the 2050s and by 2.5°C in the 2070s, as the result of climate change and population growth. Despite the foreseeable population stabilization in China, changes in population-weighted temperature are projected to be higher than changes in temperature itself for the majority of the 33 provinces (ranging from 0.02°C to 1.27°C, or 1% to 126% higher in the 2050s and from 0.02°C to 1.16°C, or 1% to 73% higher in the 2070s), with the largest differences mainly occurring in Western China. The impact of urbanization is projected to be relatively insignificant. Our findings provide evidence of possible underestimation of future changes in long-term exposure to summer heat if the effect of population growth is not factored in.