Background Atmospheric Aerosols Research Articles

大气气溶胶对北京杨树人工林生态系统生产力的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 大气气溶胶对北京杨树人工林生态系统生产力的影响 DOI: 10.5846/stxb202005281383 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31872711） Effects of atmospheric aerosols on the ecosystem productivity of a poplar plantation in Beijing Author: Affiliation: Fund Project: Impact Mechanisms of Atmospheric Aerosols on Forest Ecosystem Carbon and Water Coupling 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:大气气溶胶可以影响到达地面的太阳辐射，进而影响植物光合作用和生态系统生产力，乃至区域上的碳收支。为探究北京地区气溶胶对杨树人工林生态系统生产力的影响，利用2006-2009年北京大气气溶胶数据结合北京大兴杨树人工林涡度相关系统监测的辐射、碳通量等数据，分析了气溶胶对散射辐射、光能利用效率（LUE）、生态系统初级生产力（GPP）的影响，并利用通径分析方法探究了气溶胶和生态环境因子对GPP的直接和间接影响。结果表明，北京市气溶胶光学厚度（AOD）具有明显的季节变化特征：春、夏两季大于秋、冬季，夏季气溶胶光化学厚度最大。大气气溶胶显著影响了地表辐射组分以及温度、湿度环境因子，随着AOD从0增大到3，总辐射减小了43.63%，散射辐射增加132.26%，散射辐射比例增大了2.55倍，而相对湿度增大48.52%，日温差增大3℃左右。当生态系统受水分胁迫时，气溶胶对生态系统生产力无显著影响，当生态系统处于非水分胁迫时，杨树人工林生态系统光能利用效率和生产力随着气溶胶浓度增大先增大后减小，当AOD为1.0-1.6时，GPP维持在较高的水平，当AOD>2.5时，GPP显著减小且小于背景气溶胶（AOD<0.4）的GPP。通径分析表明，水分胁迫条件下，气溶胶对杨树人工林生态系统生产力的间接影响很小；非水分条件下，散射辐射对生态系统生产力影响最大，气溶胶可以通过增大散射光施肥效应来增大生态系统生产力。不同的水分条件下气溶胶对杨树人工林生态系统的影响不同，非水分胁迫条件下适宜的气溶胶增大杨树人工林生态系统的生产力，严重的气溶胶污染（AOD>1.5）则导致杨树生态系统生产力下降。 Abstract:Atmospheric aerosols can affect the solar radiation reaching the ground, which in turn affects plant photosynthesis and ecosystem productivity, and even regional carbon balance. With the further development of global change, atmospheric aerosols pollution and drought stress coexist in some regions, and the high frequency and long duration of drought stress may lead to the conversion of ecosystems from carbon sinks to carbon sources. However, little is known about whether atmospheric aerosols can increase ecosystem productivity when the ecosystem are under water stress. Therefore, in this study we investigated the effects of atmospheric aerosols on diffuse radiation, light utilization efficiency (LUE) and the gross primary productivity (GPP) of poplar plantation under different water conditions in Beijing. The direct and indirect effects of atmospheric aerosols and ecological factors on GPP were explored by the path analysis method, which used the atmospheric aerosols data from 2006 to 2009 and combined with the radiation and carbon flux data monitored by Eddy covariance system in Daxing poplar in Beijing. The results showed that Beijing's atmospheric optical depth (AOD) had obviously seasonal change characteristics. The AOD was higher in spring and summer than that in autumn and winter, and the AOD was the largest in summer. The atmospheric aerosols had significant effects on radiation and micrometeorological factors. With the increase of AOD from 0 to 3, photosynthetically active radiation (PAR) decreased by 43.63%, diffuse radiation increased by 170%, and the fraction of diffuse radiation increased by 2.55 times, while the relative humidity increased by 48.52% and daily temperature difference increased about 3℃. When the ecosystem was under moisture stress, the atmospheric aerosols had no effect on the GPP. When the ecosystem was under non-moisture stress, the LUE and GPP of poplar plantation ecosystem increased first and then decreased with the increase of aerosol concentration. When the AOD was 1.0-1.6, the GPP was maintained at a high level. When the AOD>2.5, the GPP significantly decreased and less than the GPP of the background atmospheric aerosol (AOD<0.4). The path analysis showed that the indirect effect of atmospheric aerosols on ecosystem productivity of poplar plantation was not significant under water stress, the diffuse radiation had the greatest influence on the GPP, and the atmospheric aerosols could increase the ecosystem productivity by increasing diffuse fertilization effect under non-moisture stress. Overall, the atmospheric aerosols had different effects on poplar plantation ecosystem under different water conditions. The suitable atmospheric aerosols could increase the productivity of poplar plantation ecosystems, while severe atmospheric aerosols pollution (AOD>1.5) led to a decrease in poplar ecosystem productivity under non-water stress conditions. 参考文献 相似文献 引证文献

The Optical Properties of Aerosols at the Summit of Mount Tai in May and June and the Retrieval of the Complex Refractive Index

To study the optical properties of background atmospheric aerosols in East China, we carried out observations of the physical, chemical and optical properties of atmospheric aerosols at the summit of Mount Tai (Mt. Tai, 1533.7 m above sea level) from 13 May to 25 June 2017. The results show that the average scattering coefficient ( σ sca , 550 ) at 550 nm of the aerosols at the summit of Mt. Tai is 40.3 Mm−1, and the average absorption coefficient ( σ abs , 550 ) at 550 nm is 16.0 Mm−1. The complex refractive index of aerosols is a key parameter for aerosol retrieval and modeling. There are few studies on the equivalent complex refractive index of aerosol in the Taishan area. We calculated the aerosol equivalent complex refractive index using the observed aerosol scattering coefficients, absorption coefficients and particle size distribution data, providing more data support for future modeling in this region. The real part (n) of the complex refractive index at 550 nm of aerosol ranges from 1.31 to 1.98 (mostly under 1.50), with an average value of 1.38, while the imaginary part (k) ranges from 0.014 to 0.251 (less than 0.10 for over 95% samples), with an average value of 0.040. The analysis of the n and k of the aerosol average complex refractive index shows that the scattering properties of the aerosols at the summit of Mt. Tai are relatively weak and the absorption properties are relatively strong when compared with those of other kinds of aerosols. The k of the aerosol complex refractive index at the summit of Mt. Tai has strong correlations with the wind speed, temperature, as revealed by the correlation analysis.

Sulfur isotope analysis for representative regional background atmospheric aerosols collected at Mt. Lulin, Taiwan

Air pollution resulted from fossil fuel burning has been an environmental issue in developing countries in Asia. Sulfur-bearing compounds, in particular, are species that are regulated and monitored routinely. To assess how the species affect at local and global scales, regional background level has to be defined. Here, we report analysis of sulfur isotopes in atmospheric sulfate, the oxidation end product of sulfur species, in particulate phase collected at the Lulin observatory located at 2862 m above mean sea level in 2010. The averaged sulfate concentration for 44 selected samples is 2.7 ± 2.3 (1-σ standard deviation) μg m−3, and the averaged δ34S is 2.2 ± 1.6‰, with respect to the international standard Vienna Canyon Diablo Troilite. Regardless of the origins of air masses, no noticeable difference between the low-altitude Pacific and high-altitude free troposphere sulfate aerosols is observed. Also, no identifiable seasonal cycle in seen. Correlation analysis with respect to coal burning tracers such as lead and oil industry tracers such as vanadium shows sulfate concentration is in better correlation with vanadium (R2 = 0.86, p-value < 0.001) than with lead (R2 = 0.45, p-value < 0.001) but no statistically significant correlation is found in δ34S with any of physical quantities measured. We suggest the sulfate collected at Lulin can best represent the regional background level in the Western Pacific, a quantity that is needed in order to quantitatively assess the budget of sulfur in local to country scales.

Development of a self-cleaning dispersion and exposure chamber: Application to the monitoring of simulated accidents involving the generation of airborne nanoparticles

The release of hazardous nanoparticulate matter in accidental situations was simulated in a specially designed 13-m3 stainless steel airtight chamber, which allowed the dispersion analysis of airborne matter in a practically particle-free environment (less than 2 #/cm3) and in presence of background atmospheric aerosols. A fast recovering of the initial situation was achieved by means of a tandem HEPA-filtered air and deionized water system. Both unintended spilling of silica-based nanoparticulate powders and continuous emission of 100-nm SiO2 nanoparticles were used as aerosol generation events. The emission of airborne nanoparticles was analyzed in terms of particle number concentrations (PNC), size distributions and source strengths. The emission of nanoparticulate aerosols reached peak PNC for particles in the range from 5nm to 1μm with source strengths about 108 #/h in a background-filled environment and 1010 #/h in a practically particle-free atmosphere. No agglomeration was noticed for the released nanoparticles, suggesting that PNC was low enough to prevent coagulation and that particle diameters were over 80nm. Results indicate that emitted matter was within the range of the most penetrating particle sizes and with source strengths similar to accidental scenarios.

Free and combined amino acids in marine background atmospheric aerosols over the Eastern Mediterranean

During a six-week intensive field campaign at a background marine site of the Eastern Mediterranean, consecutive 24-h air samples were collected and analyzed for combined (CAA) and free amino acids (FAA), as well as for key chemical characteristics of aerosols. The total concentration of CAA (719 ± 326 pmol m−3) was on average four times higher than that of FAA (172 ± 147 pmol m−3), while glycine was the most abundant compound detected in both FAA and CAA. Back-trajectory analysis demonstrated that the geographical origin of the air masses did not have a significant influence on the atmospheric levels of amino acids. Wind speed was found to be the most important meteorological factor and it exhibited a negative correlation with both FAA and CAA. Moreover, FAA and CAA concentrations showed a more pronounced correlation with water-soluble organic carbon (WSOC) than elemental carbon. On average, FAA and CAA accounted for 0.3 ± 0.2% and 1.8 ± 0.8% of WSOC, respectively. The levels of anionic surfactants determined as methylene blue active substances did not show any positive correlation with CAA, while the corresponding correlation with FAA was only of marginal significance. The total protein concentration measured by NanoOrange assay was six times higher compared to that measured through CAA. It is suggested that the results from the application of commercially available protein quantitation kits should always be considered with caution, as these are more prone to matrix-related interferences.

A novel method for determination of low molecular weight dicarboxylic acids in background atmospheric aerosol using ion chromatography

This paper describes a novel gradient elution ion chromatographic method using a Dionex AS11 system for the determination of low molecular weight dicarboxylic acids (low- M w DCAs) in background atmospheric aerosol. Interference with the oxalic acid peak from sulfate in background PM 2.5 aerosol, 15.8 times the oxalic acid concentration, was remedied by removing sulfate using a barium cartridge, whilst interference with the malonic acid peak from carbonate was reduced by using a carbonate removal device. An alternative remedy to sulfate interference was use of an AS14 system using isocratic eluent, and this produced good resolution of oxalic acid from a high sulfate peak. In both the AS11 and the AS14 system, linear correlation coefficients were at all times >0.9990 with excellent linear range, the recoveries ranged from 92.8 to 106%, with relative standard deviation of 3.67–6.30%, whilst method detection limits (MDLs) ranged from 0.36 μg L −1 for malic acid to 3.87 μg L −1 for maleic acid. These data indicate that the analytical methods developed herein produce excellent separation efficiency and good determination of low- M w DCAs with satisfactory accuracy, recoveries, and MDLs. Samples left at room temperature (20 °C) for 300 min in a simulation of the ‘waiting time’ involved in the proposed IC analysis decayed to between 86% (oxalic acid) and 39% (succinic and malonic acids) of their original concentration, whilst at 4 °C concentrations remained at 96–101% of original, indicating that maintaining samples at a low temperature prior to injection into the IC analyzer is vital for obtaining accurate results when analyzing low- M w DCAs. Oxalic acid was found to be the most prevalent low- M w DCA in background aerosol, comprising 57% of the total low- M w DCAs and 0.959% of the PM 2.5 aerosol mass, followed by succinic acid and malonic acid.

A spectral correlation method of measuring the fraction composition of an aerodispersed medium: Measurement and computation algorithms

A spectral correlation method is proposed for measuring the fractional concentrations of background atmospheric aerosols on the basis of the attenuation coefficient β(λ) and the back-scattering coefficient {ie320-01} together with the equations of multiple regression for the coarse, transitive, and accumulative fractions of the aerosol. It is shown that one can improve the accuracy in measurements of β(λ), {ie320-02}, and the fractional concentrations by the implementation of measurement and computational algorithms.

Multiple regression equations for fractional concentrations of atmospheric aerosol and spectral extinction coefficients

We have studied the sensitivity of the coupling coefficients between the spectral extinction coefficients β(λ) and the fractional aerosol concentrations to microstructural variations in the aerosol. We have calculated and analyzed the spectral dependences of the correlation coefficients between the indicated characteristics. We have obtained the multiple regression equations for the fractional concentrations of background atmospheric aerosol and the spectral extinction coefficients at wavelengths of λ = 0.350 µm, 0.532 µm, and 1.060 µm with a large spread in the microphysical characteristics of the aerosol, allowing us to determine its fractional composition with accuracy that is satisfactory for many practical requirements, without using additional measurements of the microstructural parameters or taking into account their spatial variations.

Remote sensing of aerosols over North American land surfaces from POLDER and MODIS measurements

We examine two different aerosol remote sensing approaches based on polarized ADEOS-1 POLDER measurements and on multispectral EOS Terra MODIS dark target retrieval. Satellite-derived aerosol optical depth (AOD) is assessed from comparisons with AERONET/AEROCAN ground-based sunphotometer AOD measurements over North America. The results show that the POLDER polarization retrieval method for AOD at 865 nm yields large scatter with a root mean square error (RMSE) of 0.11 for single pixels, and RMSE=0.092 for 3×3 windows and a systematic mean overestimation of +0.036 and +0.031 for single pixels and 3×3 windows, respectively. The correlation statistics can be significantly improved by employing the Size Weighted Aerosol Index (SWAI) defined as the product of the AOD times the Angstrom exponent, showing a correlation coefficient ( R ) of 0.68 with RMSE=0.072 for single pixels and R =0.75 with RMSE=0.065 for the 3×3 windows. We have checked the reliability of the POLDER inversion scheme by comparing the aerosol polarized radiance (i.e., corrected for ground and molecular contributions) with AOD sunphotometer measurements at 670 nm for five different sites ( R =0.36). The MODIS capability for monitoring seasonal and long-term aerosol dynamics is assessed by analyzing the 8-day MODIS AOD product at 550 nm (Level-3 product). The retrieved AOD accuracy is variable depending on sites and observed AOD dynamic range; for the overall database ( N =1200 points), R =0.37, RMSE=0.17 and Bias=+0.088. We illustrate how satellite-derived AOD images can be used to monitor spatial and temporal aerosol dynamics at the regional scale (anthropogenic pollution events over the North-Eastern American coast) and at the continental scale (dust storm events and mean seasonal background atmospheric aerosol loading). It appears that aerosol mapping from satellite images is still difficult over North America, particularly at high latitudes where AOD variations are generally relatively small.

Remote sensing of aerosols over North American land surfaces from POLDER and MODIS measurements

We examine two different aerosol remote sensing approaches based on polarized ADEOS-1 POLDER measurements and on multispectral EOS Terra MODIS dark target retrieval. Satellite-derived aerosol optical depth (AOD) is assessed from comparisons with AERONET/AEROCAN ground-based sunphotometer AOD measurements over North America. The results show that the POLDER polarization retrieval method for AOD at 865 nm yields large scatter with a root mean square error (RMSE) of 0.11 for single pixels, and RMSE=0.092 for 3 � 3 windows and a systematic mean overestimation of +0.036 and +0.031 for single pixels and 3 � 3 windows, respectively. The correlation statistics can be significantly improved by employing the Size Weighted Aerosol Index (SWAI) defined as the product of the AOD times the Angstrom exponent, showing a correlation coefficient (R) of 0.68 with RMSE=0.072 for single pixels and R ¼ 0:75 with RMSE=0.065 for the 3 � 3 windows. We have checked the reliability of the POLDER inversion scheme by comparing the aerosol polarized radiance (i.e., corrected for ground and molecular contributions) with AOD sunphotometer measurements at 670 nm for five different sites (R ¼ 0:36). The MODIS capability for monitoring seasonal and long-term aerosol dynamics is assessed by analyzing the 8-day MODIS AOD product at 550 nm (Level-3 product). The retrieved AOD accuracy is variable depending on sites and observed AOD dynamic range; for the overall database (N ¼ 1200 points), R ¼ 0:37; RMSE=0.17 and Bias=+0.088. We illustrate how satellite-derived AOD images can be used to monitor spatial and temporal aerosol dynamics at the regional scale (anthropogenic pollution events over the North-Eastern American coast) and at the continental scale (dust storm events and mean seasonal background atmospheric aerosol loading). It appears that aerosol mapping from satellite images is still difficult over North America, particularly at high latitudes where AOD variations are generally relatively small. r 2004 Elsevier Ltd. All rights reserved.

Correlations in the chemical composition of rural background atmospheric aerosol in the UK determined in real time using time-of-flight mass spectrometry.

An aerosol time-of-flight mass spectrometer (ATOFMS) was used to determine, in real time, the size and chemical composition of individual particles in the atmosphere at the remote inland site of Eskdalemuir, Scotland. A total of 51,980 particles, in the size range 0.3-7.4 microm, were detected between the 25th and 30th June 2001. Rapid changes in the number density, size and chemical composition of the atmospheric aerosol were observed. These changes are attributed to two distinct types of air mass; a polluted air mass that had passed over the British mainland before reaching Eskdalemuir, interposed between two cleaner air masses that had arrived directly from the sea. Such changes in the background aerosol could clearly be very important to studies of urban aerosols and attempts at source apportionment. The results of an objective method of data analysis are presented. Correlations were sought between the occurrence of: lithium, potassium, rubidium, caesium, beryllium, strontium, barium, ammonium, amines, nitrate, nitrite, boron, mercury, sulfate, phosphate, fluorine, chlorine, bromine, iodine and carbon (both elemental and organic hydrocarbon) in both fine (d < 2.5 microm) and coarse (d > 2.5 microm) particle fractions. Several previously unreported correlations were observed, for instance between the elements lithium, beryllium and boron. The results suggest that about 2 in 3 of all fine particles (by number rather than by mass), and 1 in 2 of all coarse particles containing carbon, consisted of elemental carbon rather than organic hydrocarbon (although a bias in the sensitivity of the ATOFMS could have affected these numbers). The ratio of the number of coarse particles containing nitrate anions to the number of particles containing chloride anions exceeded unity when the air mass had travelled over the British mainland. The analysis also illustrates that an air mass of marine origin that had travelled slowly over agricultural land can accumulate amines and ammonium.

Contents of 3,4-benzo(a)pyrene and dibutyl phthalate in background atmospheric aerosols in West Siberia, and in wind drifted aerosol exhaust out of the chimneys of heat power station

Contents of 3,4-benzo(a)pyrene and dibutyl phthalate in background atmospheric aerosols in West Siberia, and in wind drifted aerosol exhaust out of the chimneys of heat power station

Vertical distribution of atmospheric aerosol size distribution over south-central New Mexico

The vertical distribution of background atmospheric aerosols was measured over south-central New Mexico as a part of the Atmospheric Lidar Verification Experiment (ALIVE) during four research field periods in the summers and winters of 1989 and 1990. Aerosol size distribution was measured from the surface up to 4500 m above sea level (asl) over the particle size range 0.1∼32 μm, using two Particle Measuring Systems (PMS) probes mounted on the wings of the NOAA King Air research aircraft. Vertical profiles of aerosol number concentrations of both fine- (0.1–2.0 μm) and coarse- (>2.0 μm) particle modes show seasonal differences, with higher number concentrations and higher mixed layer heights during summers. The measured aerosol size distribution data of each ALIVE intensive were averaged for boundary layer and free troposphere regions. These data mostly exhibit bi-modal distributions, typical for the continental atmospheric aerosols. Exceptions were the free troposphere size distributions measured during December 1989 (ALIVE III) and June 1990 (ALIVE IV), which resemble Junge's power-law distribution. Each of the averaged aerosol size distributions was approximated by the sum of log-normal distributions. Different characteristics of aerosol size distribution were observed between the two summer measurements of 1989 and 1990. Back-trajectory analysis revealed that decreased aerosol concentrations were observed during June 1990 when the air mass was transported from the southwestern U.S.A.

Free tropospheric reservoir of natural sulfate

10Be is used as a spike of the natural background atmospheric aerosol to calculate the global flux of sulfur (FS) into the free troposphere. The sulfate and10Be concentrations determined in polar snow are compared. On the basis of an annual10Be production rate of 1.21 106 at.cm-2, a very low figure of 2.9 Tg S a-1 is calculated for FS, which suggests that most of the sulfur emitted at ground level remains in the boundary layer. The role of OCS in the upper tropospheric sulfur budget is reviewed. It is also shown that cataclysmic volcanic eruptions may disturb considerably for 1–2 years this vast background tropospheric sulfur reservoir.

The chemical composition of remote area aerosols

Studies of background atmospheric aerosols have been conducted at a variety of locations during the past ten years. Most sites that have been studied are dominated by regional aerosols, and have relatively high levels of crustal dust or sea salt. The cleanest place on the earth's surface is the Antarctic, as demonstrated by measurements conducted over the last few years. Atmospheric particles collected there have been analyzed by neutron activation analysis, and the results show that the major mass of aerosol is sulfate during the summer season. Minor quantities of crustal dust, sea salt and meteoritic debris were also observed along with a rather small component made up of volatile elements, which are believed to be due, in part, to volcanism. During the winter season, the levels of sulfate, crustal dust and meteoritic debris were observed to decrease, and the level of sea salt increased almost twenty fold due to severe storm activity off the coast of Antarctica and enhanced transport from these boundary areas into the center of the continent. At the same time, transport from the upper troposphere into the lower, near surface areas was severely hindered. The chemistry of the aerosol appears to be very similar each summer season and, between 1971 and 1978, no drastic changes in the composition of the aerosols collected at the South Pole can be noted.

The background atmospheric aerosol

An attempt is made to define the ‘background atmospheric aerosol’ and the reasons and methods for measuring it are discussed. Three current programmes for monitoring the tropospheric aerosol level ...

Comparison between the light extinction aerosol mass concentration relationship of atmospheric and air pollutant emission aerosols

A comparison between the measured and calculated light extinction-aerosol mass concentration relationship for atmospheric and source emission aerosols is presented. A parameter K, defined as the specific particulate volume/light extinction coefficient ratio (cm 3 m −3/m −1) is used in the comparison. The measured magnitudes range from 0·256 to 0·487 for averaged atmospheric Ks and from 0.06 to 0.78 for individual source emission Ks. Additional K data for source emissions and background atmospheric aerosols would be useful for estimating the contribution of various aerosol sources to atmospheric visibility reduction.