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1.
We have estimated and compensated the error in long-term series of the aerosol optical thickness (AOT) calculated from the data on direct integral solar radiation measured by a standard actinometer at the Meteorological Observatory of the Moscow State University (MO MSU) for strong atmospheric turbidity conditions. The necessary corrections have been obtained by the Monte-Carlo simulation of the actinometry measurements for different atmospheric conditions, taking into account the angular size of the field of view of the instrument; and a special correctional formula has been obtained. This correction formula has been applied for all timed AOT values of above 0.5 observed at the MO MSU for the entire time period from 1955 to 2013. Changes in the long-term average AOT values in Moscow occurred only when the smoky haze from the forest and peat fires affected the aerosol turbidity of the atmosphere. Here, the significant decreasing trend of aerosol optical depth of the atmosphere from 1955 to 2013 has been retained with the same confidence level.  相似文献   

2.
Based on Total Ozone Mapping Spectrometer (TOMS) monthly aerosol optical thickness (AOT) measurements in 1980-2001 a study is made of space/time patterns and difference between land and sea of AOT 0.50 μm thick over China, which are put into correlation analysis with synchronous ex- treme temperature indices (warm/cold day and night). Results suggest that 1) the long-term mean AOT over China is characterized by typical geography, with pronounced land-sea contrast. And AOT has significant seasonality and its seasonal difference is diminished as a function of latitude. 2) On the whole, the AOT displays an appreciably increasing trend, with the distinct increase in the eastern Qinghai-Tibetan plateau and SW China, North China, the mid-lower Changjiang (MiLY) valley as well as the South China Sea, but marginal decrease over western/northern Xinjiang and part of South China. 3) The AOT over land and sea is marked by conspicuous intra-seasonal and -yearly oscillations, with remarkable periods at one-, two-yr and more (as interannual periods). 4) Land AOT change is well correlated with extremely temperature indexes. Generally, the correla- tions of AOT to the extreme temperature indices are more significant in Eastern China with 110°E as the division. Their high-correlation regions are along the Southern China coastline, the Loess Plateau and the Sichuan Basin, and even higher in North China Plain and the mid-lower Changjiang River reaches. 5) Simulations of LMDZ-regional model indicate that aerosol effects may result in cooling all over China, particularly in Eastern China. The contribution of aerosol change may result in more decrease in the maximum temperature than the minimum, with decrease of 0.11/0.08 K for zonal average, respectively.  相似文献   

3.
The results of studies of aerosol optical thickness (AOT) in Dushanbe conducted from July 2010 to March 2011 within the AERONET program are discussed. The statistical characteristics of AOT have been shown to significantly vary during dust intrusions. The seasonal variations in the dustiness of the atmosphere have been analyzed.  相似文献   

4.
通过与地基气溶胶观测数据的对比,确认了SeaWiFS气溶胶光学厚度产品用于研究中国海域气溶胶分布和变化特征的有效性。在此基础上,分析了中国海域气溶胶光学厚度的季节变化和地理分布特征。研究结果表明,中国东部海域平均气溶胶光学厚度存在以中纬度为中心的纬向分布;受沙尘、季风气候的影响,中国海域气溶胶光学厚度存在季节变化,不同海区有不同的季节变化和分布特征。渤海、黄海及东海有类似的变化特征,春季都受到沙尘气溶胶的影响,使中国东部海域气溶胶光学厚度普遍高于0.160,且对东海的影响最大;夏、秋季逐渐减小,冬季有所回升。南海气溶胶光学厚度均值为0.150,随时间变化不明显,但地理分布变化显著;受季风气候的影响,从春季到冬季,气溶胶光学厚度高值中心从高纬海域向低纬海域转移,范围也逐渐扩大。冬季南海大部分海域气溶胶光学厚度都达到0.160以上,是整个中国海域冬季气溶胶光学厚度最大的海区。气溶胶光学厚度的季节变化和地理分布特征为研究中国海区域气候变化和海洋生态提供了依据。  相似文献   

5.
基于卫星的气溶胶光学厚度(aerosol optical thickness,AOT)是研究大气污染程度及时空变化的重要参考,由于大气污染物排放特征、地理和气候背景不同,不同区域AOT的时空分布及其与地面大气污染物质量浓度的相关性存在一定的差异。选取了2017年7月—2020年7月山东89个国家环境空气质量监测站数据、日本宇宙航空研究开发机构(Japan Aerospace Exploration Agency,JAXA)发布的葵花8号和9号气象卫星(Himawari-8/9)AOT产品、欧洲中期天气预报中心(European Center for Medium-Range Weather Forecasts,ECMWF)的ERA5再分析数据产品,研究了山东地区卫星AOT时空分布特征,AOT与地面污染物质量浓度的相关性,并得出了以下结论:1)山东存在两个主要的AOT低值区,分别位于鲁中山区一带,半岛丘陵并延伸到东部沿海一带,低值区的分布没有明显的季节变化;山东AOT年平均的高值区主要分布在山东西部、南部与外省接壤附近地区,以及渤海南部至莱州湾沿岸一带,在分析气溶胶跨省传输时值得关注。不同季节AOT的高值区分布存在差异。2)山东AOT白天变化呈现双峰结构,08时由峰值逐渐下降,11时转为上升,14时达全天最大值0.608;AOT的日变化趋势与细颗粒物(PM2.5)、O3等大气污染物质量浓度变化明显不同,是影响其相关性的重要因素。AOT月际变化中,存在两个显著的峰值6月(0.648)和10月(0.622),2月AOT最低。AOT的季节变化与地面污染物质量浓度的季节变化呈现一定的反位相特征。3)总体上AOT与PM2.5、O3等主要大气污染物质量浓度的相关性不高,一年之中,6月AOT与污染物的相关程度最低,1月的相关性最高;15—17时是AOT与污染物相关性最强的时间段,而10时相关性最差。单凭AOT难以定量反映污染物的分布特征,使用卫星开展地面大气污染监测分析还需纳入更多的因子进行分析。  相似文献   

6.
The evolution of smoke plume over European Russia (ER) during the massive forest and peatbog fires of summer 2010 has been studied using observations of aerosol optical depth (AOD) from MODIS instruments (both Aqua and Terra platforms), objective analysis of meteorological fields performed at the Russian Hydrometeorological Research Center, NCEP/NCAR reanalysis, as well as upper air data. A relation between the structure inhomogeneities of the AOD field and regional atmospheric circulation has been found. It is shown that, on August 5–9, 2010, the maximum of smoke pollution did complete turn around Moscow, while remaining at a distance of 200 to 650 km from the megacity. Both regionally averaged shortwave aerosol radiative forcings (ARFs) at the top and the bottom of the atmosphere are estimated for the period of extreme smoke pollution over ER. The spatial distributions of ARF values over the territory of the region and the estimates of the local and spatially distributed thermal effects of smoke aerosol are given. It is shown that, on August 5–9, 2010, the spatial distribution of AOD and the calculated thermal effects of smoke aerosol were in agreement with the spatial distributions of air-temperature anomalies observed in the lower 1.5-km layer of the atmosphere. MODIS’s AOD data obtained during the wildfires were validated by AOD observations from the CIMEL sun photometer operated at the AERONET station Zvenigorod.  相似文献   

7.
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8.
Izvestiya, Atmospheric and Oceanic Physics - The smoke haze over the European part of Russia (EPR) and Belorus in July 2016 has been studied with the use of aerosol optical thickness (AOT) data...  相似文献   

9.
The spatial and temporal variabilities of the aerosol optical thickness (AOT) and the total carbon monoxide content (CO) in the period of development and weakening of mass forest and peatbog fires in the European Russia territory (ERT) in the summer of 2010 are investigated from data of the AOT and CO satellite observations. The intensities of aerosol and CO emissions in the period of mass fires and the ratio of the emission factors of aerosol particles and CO are estimated on the basis of calculations of the smoke and CO masses over the ERT. The interrelation between variations in the levels of the regional pollution by combustion products and the variability of meteorological parameters is investigated. Various aspects of the manifestation of radiation effects of aerosols are discussed. The synchronization of weekly signals of the AOT, CO, and meteorological parameters in the period of mass fires is noted.  相似文献   

10.
Peculiarities of the formation of carbon gas and fine aerosol emissions into the atmosphere during wildfires are analyzed. A prompt satellite monitoring system and technique for the assessment of burnt areas and volumes of CO2, CO, and PM2.5 emissions from wildfires are described. The results of satellite monitoring of the Russian Federation and some Russian regions for different months over 2010–2014 are given; burnt areas and volumes of carbon gas and aerosol emissions throughout the entire territory are assessed. The peculiarities of seasonal frequencies of wildfires and volumes of hazardous gas and fine aerosol emissions in the regions under study are identified.  相似文献   

11.
This is a comprehensive study of the physicochemical characterization of multicomponent aerosols in the smoky atmosphere of Moscow during the extreme wildfires of August 2010 and against the background atmosphere of August 2011. Thermal–optical analysis, liquid and ion chromatography, IR spectroscopy, and electron microscopy were used to determine the organic content (OC) and elemental content (EC) of carbon, organic/inorganic and ionic compounds, and biomass burning markers (anhydrosaccharides and the potassium ion) and study the morphology and elemental composition of individual particles. It has been shown that the fires are characterized by an increased OC/EC ratio and high concentrations of ammonium, potassium, and sulfate ions in correlation with an increased content of levoglucosan as a marker of biomass burning. The organic compounds containing carbonyl groups point to the process of photochemical aging and the formation of secondary organic aerosols in the urban atmosphere when aerosols are emitted from forest fires. A cluster analysis of individual particles has indicated that when the smokiest atmosphere is characterized by prevailing soot/tar ball particles, which are smoke-emission micromarkers.  相似文献   

12.
利用2003—2008年在渤海所测的212组气溶胶数据,研究了气溶胶光学厚度(AOT)、浑浊度系数(β)和ngstrm指数α的时空分布规律,并初步探讨了气溶胶特征参数之间的关系。结果表明,在时间分布方面,渤海气溶胶光学厚度、浓度和粒径尺度在一天中的变化比较小,中午AOT较大,10点左右AOT较小。从6月份到9月份,AOT、β和α的范围和均值均呈下降趋势;3月份AOT、β和α均明显小于六、8、9月份的对应值。离岸25km之内的大部分地区,AOT随离岸距离的增大而减小;但25km以外,气溶胶变化没有规律。比较而言,气溶胶AOT和β变化比较一致。浑浊度系数(浓度因子)β比ngstrm指数(尺度因子)α对气溶胶光学厚度AOT的影响更明显,AOT和β的关系可采用一阶线性回归方程表示。  相似文献   

13.
阐述了气溶胶散射对太阳光衰减的影响和对观测数据的统计分析.作者使用手持式五波段太阳光度计和臭氧监测仪对青岛崂山区陆域和渤海海域的大气衰减进行了较长时间的观测.分析表明,对可见光和近红外波段电磁渡的大气衰减贡献最大的是气溶胶散射,气溶胶散射的光学厚度随波长的增大而减小,但是它在大气总光学厚度中占的比例随波长的增大而增加.在青岛崂山区冬季,对应于440nm波长的气溶胶散射光学厚度主要分布在0.4～0.6和1.5～1.6区间,浑浊度系数α主要分布在0.15～0.45区间,埃斯特朗指数β主要分布在1.0～1.4区间.从时间上看,α和β在1d内的变化不大,但逐日变化非常显著.与晴天相比,青岛崂山区冬季雾天的气溶胶散射光学厚度增加了大约一倍,较大的浑浊度系数和较小的埃斯特朗指数表明,雾天的大气具有气溶胶散射的光学厚度大、粒子浓度大和粒径尺度大的特点.通过与海上观测数据的比较可见,青岛崂山区陆地冬季在雾天时的气溶胶分布与渤海夏季时相似,青岛崂山区陆地冬季在晴天无云时的气溶胶分布与渤海秋季时相似.  相似文献   

14.
The level of cosmic radiation has been shown to affect the rate of nanoparticle formation from gas emissions of natural and anthropogenic origins. The acceleration of particle formation processes is mainly caused by the increased concentration of atmospheric ions, which serve as condensation nuclei and thus strongly change the rate of aerosol charging processes. This paper provides a brief overview of the main processes leading to the formation of nanoparticles in the atmosphere. These processes include nucleation, condensational growth, charged particle growth, charging of aerosol particles, and recombination. Particular emphasis has been placed on the role of particle sizes in charging processes. Also, we discuss the influence of aerosol sinks on the rate of aerosol formation.  相似文献   

15.
Phenols represent a group of organic pollutants frequently found in many near-shore marine systems. The microbial degradation of phenols, mainly by bacteria and fungi, has been extensively studied both experimentally and theoretically, but only relatively recently the capabilities of some algae for phenols biodegradation gained interest. The biodegradation of phenols by microalgae occurs only under aerobic conditions. In this paper, a dynamic energy budget model is proposed for describing aerobic biodegradation of phenolic compounds by microalgae and qualitatively validated against experimental data. A microalgal cell has the ability to produce biomass via the autotrophic assimilation (uptake of light and dissolved inorganic carbon), the heterotrophic assimilation (uptake of dissolved organic carbon) and, to a lesser extend, via the biodegradation of phenols. The rules of synthesizing units are used for the uptake and interactions of substrates and for the merging of assimilates. The model is capable of making predictions under oxygen and carbon (inorganic and organic) limiting conditions. Model predictions cover a wide range of experimental evidence, but also give a possible explanation for the inhibition of bioremoval of phenols in the presence of glucose. The dissolved oxygen profiles numerically observed show low oxygen concentration during the intermediate phase of the biodegradation process and a rapid increase after the consumption of the phenolic compound, indicating that lack of oxygen could be a limiting factor for the biodegradation of phenols. The presence of glucose increases the specific growth rate but decreases the specific biodegradation rate of the phenolic compound. Model analysis suggests that this inhibition may be due to the competition for oxygen between glucose and phenol assimilation. In general, the balance between the benefits and costs of the different types of assimilation determines the microalgal growth rates as well as the phenol biodegradation rates. Being based on general assumptions, the model can be applied to the biodegradation of a wide variety of aromatic compounds.  相似文献   

16.
Aerosol optical thickness (AOT) was retrieved from the Geostationary Ocean Color Imager (GOCI) on board the Communication, Ocean, and Meteorological Satellite (COMS) for the first time. AOT values were retrieved over the ocean at a spatial scale of 0.5 × 0.5 km2 by using the look-up table (LUT)-based separation technique. The radiative transfer model (RTM) was used for different models of atmosphere-ocean environmental conditions, taking into account the realistic variability of scattering and absorption. Ocean surface properties affected by whitecaps and pigment content were also taken into account. The results show that the radiance observed by the GOCI amounts to only 5% of the radiation that penetrated the ocean and, consequently, 95% of the radiation is scattered in the atmosphere or reflected at the ocean surface in the visible wavelengths longer than 0.6 ìm. Within these wavelengths, radiance variations at the top of atmosphere (TOA) due to pigment variations are within 10%, while the radiance variation due to wind speed is considerably higher. For verification of GOCI-retrieved AOTs, comparison between GOCI and ground-based sunphotometer measurement at Gosan, Korea (126.10°E, 33.23°N)) showed good correlation (r = 0.99). The GOCI observations obtained by using the proposed technique showed promising results for the daily monitoring of atmospheric aerosol loading as well as being useful for environmental supervisory authorities.  相似文献   

17.
The South China Sea(SCS) and the Arabian Sea(AS) are both located roughly in the north tropical zone with a range of similar latitude(0°–24°N). Monsoon winds play similar roles in the upper oceanic circulations of the both seas. But the distinct patterns of chlorophyll a(Chl a) concentration are observed between the SCS and the AS.The Chl a concentration in the SCS is generally lower than that in the AS in summer(June–August); the summer Chl a concentration in the AS shows stronger interannual variation, compared with that in the SCS; Moderate resolution imaging spectroradiometer(MODIS)-derived data present higher atmospheric aerosol deposition and stronger wind speed in the AS. And it has also been found that good correlations exist between the index of the dust precipitation indicated by aerosol optical thickness(AOT) and the Chl a concentration, or between wind and Chl a concentration. These imply that the wind and the dust precipitation bring more nutrients into the AS from the sky, the sub-layer or coast regions, inducing higher Chl a concentration. The results indicate that the wind velocity and the dust precipitation can play important roles in the Chl a concentration for the AS and the SCS in summer. However aerosol impact is weak on the biological productivity in the west SCS and wind-induced upwelling is the main source.  相似文献   

18.
The solubility of iron, aluminium, manganese and phosphorus has been determined in aerosol samples collected between 49°N and 52°S during three cruises conducted in the Atlantic Ocean as part of the European Union funded IRONAGES programme. Solubilities (defined at pH 4.7) determined for Fe and Al in samples of Saharan dust were significantly lower (medians 1.7% and 3.0%, respectively) than the solubilities of these metals in aerosols from other source regions (whole dataset medians 5.2% and 9.0%, respectively). Mn solubility also varied with aerosol source, but the median solubility of Mn in Saharan dust was very similar to the median for the dataset as a whole (55% and 56%, respectively). The observed solubility of aerosol P was ∼ 32%, with P solubility in Saharan aerosol perhaps as low as 10%. Laboratory studies have indicated that aerosol Fe solubility is enhanced by acid processing. No relationship could be found between Fe solubility and the concentrations of acid species (non-seasalt SO42−, NO3−) nor the net acidity of the aerosol, so we are unable to confirm that this process is significant in the atmosphere. In terms of the supply of soluble Fe to oceanic ecosystems on a global scale, the observed higher solubility for Fe in non-Saharan aerosols is probably not significant because the Sahara is easily the dominant source of Fe to the Atlantic. On a smaller scale however, higher solubility for aerosol Fe may alter our understanding of Fe cycling in regions such as the remote Southern Ocean.  相似文献   

19.
王浩  黄文骞  王健 《海洋测绘》2021,41(2):44-48
针对目前传统大气辐射传输模型使用时难以确定气溶胶光学厚度的问题,提出一种仅依靠影像自身信息的大气校正算法,该算法针对南海水域清澈的特点,将暗像元法和大气辐射传输模型相结合,通过暗像元匹配和迭代运算确定气溶胶。实验结果表明:该算法与Sen2cor算法相比大气校正后的地物剖面光谱曲线基本一致,校正后影像能够反映出水深与蓝绿波段对数比值较好的相关性,具有较好的使用价值。  相似文献   

20.
An improved version of Ehrhardt's (1969) method for the analysis of dissolved organic carbon is described. The method, which is automated, determines the carbon dioxide with a non-dispersive infra-red analyser. The conditions of photo-oxidation have been examined in order to achieve maximum performance. It was found that careful attention needed to be paid to U-V source, “oxygen source”, pH and time or irradiation. The completeness of the method was examined by three independent procedures. We concluded that in all cases the extent of oxidation of organic material was in excess of 98%. Typical performance figures were: precision ±2.5% above 2.0 mg C l?1, approaching 0.03 mg C l?1 below 1.0 mg Cl?1; blank, equivalent to 0.3 mg C l?1; sampling frequency, 10 samples per hour. The lower limit of sensitivity is mainly governed by the blank. The upper limit of the method is greater than 40 mg C l?1.A wholly continuous modification of the method has been devised which permits on line analyses. An attentuated version of the method has been used for the analysis of total carbonate.The present and other published methods for the analysis of dissolved organic carbon in natural waters are discussed in relation to one another.  相似文献   

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