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Nobuo Sugimoto Yukari Hara Atsushi Shimizu Tomoaki Nishizawa Ichiro Matsui Masataka Nishikawa 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(1):27-39
The Asian dust events in 2008 (May 24–June 4 in 2008) and in 2009 (March 12–25, October 13–26, and December 15–28 in 2009) were analyzed with the lidar network observations, surface observations in China, Korea, Japan, and Mongolia, and with the chemical transport model CFORS. Transport of Asian dust and mixing of dust with air pollution aerosols were studied. The event of May 24 to June 4 in 2008 was a significant event unusually late in the spring dust season. The dust event of March 12–25, 2009 was an interesting example of elevated dust layer, and transport of dust from the elevated dust layer to the ground by the boundary layer activity was observed with the lidars and surface observations in Japan. The concentration of air pollution aerosols was relatively high during the dust event, and the results suggest that vertical structure as well as transport path is important for the mixing of dust and air pollution aerosols. The dust events in October and December 2009 were examples of dust events in autumn and winter. The online mode CFORS reproduced the observation data generally well, except for the event of May 24 to June 4 in 2008. The results of the fourdimensional variational assimilation of the lidar network data reproduced the dust concentration in Korea and Japan reasonably in that event. 相似文献
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In May/June 2006, the largest mineral dust experiment to date (Saharan Mineral Dust Experiment, SAMUM-1) was conducted in Southern Morocco. The aim was to characterize dust particles near the world's largest mineral dust source, and to quantify dust-related radiative effects. At one of the two ground-based measurement sites dust particle size distribution, optical, hygroscopic, chemical and structural particle characteristics were measured. One research aircraft mainly measured solar spectral irradiances and surface albedo. The other aircraft provided in situ physical aerosol measurements and samples and lidar profiles through the dust layers. Three ground-based lidars were operated at the second ground-based measurement site. They determined optical dust properties, particle shape and temporal development of dust layers. Columnar, ground-based sun photometer measurements complemented the lidar data. Additionally a station in Évora, Portugal monitored dust outbreaks from the North African source region to the Iberian Peninsula during SAMUM-1.
Volumetric and columnar closure exercises utilized these detailed measurements of dust characteristics together with optical and radiative transfer models. Concurrent developments of a mesoscale dust transport model were validated with the experimental data. The paper gives an overview over rationale and design of SAMUM-1, introduces and highlights the subsequent reports on experimental and modelling results. 相似文献
Volumetric and columnar closure exercises utilized these detailed measurements of dust characteristics together with optical and radiative transfer models. Concurrent developments of a mesoscale dust transport model were validated with the experimental data. The paper gives an overview over rationale and design of SAMUM-1, introduces and highlights the subsequent reports on experimental and modelling results. 相似文献
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激光雷达作为一种新兴的主动遥感探测工具,被广泛应用于大气遥感、环境监测等领域。星载激光雷达由于其较广的探测范围、较高的时空分辨率、可获得连续的廓线数据等优势,已经成为全球及区域气溶胶和云特性观测研究的强有力工具。本文总结了自2006年CALIPSO卫星发射以来,中国科学家在利用其开展沙尘气溶胶及污染研究方面的工作,重点阐述了沙尘气溶胶的时空分布、远距离传输、分类识别、光学特性、沙尘释放、辐射与气候效应,以及灰霾和烟尘特性等方面的最新研究成果。对以上研究成果的梳理,有助于深入理解中国在利用星载激光雷达开展沙尘与污染研究的水平,也为未来开拓中国自主研发星载激光雷达的遥感应用领域奠定了基础。 相似文献
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By D. MÜLLER B. HEINOLD M. TESCHE I. TEGEN D. ALTHAUSEN L. ALADOS ARBOLEDAS V. AMIRIDIS A. AMODEO A. ANSMANN D. BALIS A. COMERON G. D'AMICO E. GERASOPOULOS J. L. GUERRERO-RASCADO V. FREUDENTHALER E. GIANNAKAKI B. HEESE M. IARLORI P. KNIPPERTZ R. E. MAMOURI L. MONA A. PAPAYANNIS G. PAPPALARDO R.-M. PERRONE G. PISANI V. RIZI M. SICARD N. SPINELLI A. TAFURO M. WIEGNER 《Tellus. Series B, Chemical and physical meteorology》2009,61(1):325-339
We observed a long-range transport event of mineral dust from North Africa to South Europe during the Saharan Mineral Dust Experiment (SAMUM) 2006. Geometrical and optical properties of that dust plume were determined with Sun photometer of the Aerosol Robotic Network (AERONET) and Raman lidar near the North African source region, and with Sun photometers of AERONET and lidars of the European Aerosol Research Lidar Network (EARLINET) in the far field in Europe. Extinction-to-backscatter ratios of the dust plume over Morocco and Southern Europe do not differ. Ångström exponents increase with distance from Morocco. We simulated the transport, and geometrical and optical properties of the dust plume with a dust transport model. The model results and the experimental data show similar times regarding the appearance of the dust plume over each EARLINET site. Dust optical depth from the model agrees in most cases to particle optical depth measured with the Sun photometers. The vertical distribution of the mineral dust could be satisfactorily reproduced, if we use as benchmark the extinction profiles measured with lidar. In some cases we find differences. We assume that insufficient vertical resolution of the dust plume in the model calculations is one reason for these deviations. 相似文献
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重叠函数的校准对地基激光雷达低空大气探测的准确性至关重要。目前被广泛用于校准拉曼激光雷达重叠函数的双通道实验标定法,需要满足弹性散射通道与氮气拉曼散射通道的重叠函数近似相等的前置条件。但实际仪器光路往往会偏离理想状态,使得该前置条件无法得到满足,导致校准失败。本文使用光线追踪法模拟重叠函数,计算了各种光路失调情况下弹性散射通道与氮气拉曼散射通道的比值,并引入了一种镜头遮蔽实验来评估双通道实验标定法的前置条件是否得到满足。数值模拟结果表明,当雷达接收面的不同象限被遮蔽时,如果弹性散射通道与氮气通道的信号强度比值基本保持不变,则满足前置条件;如果弹性散射通道与氮气通道的信号强度比值有显著差异,则可判定仪器光学系统失调,需要调整直至满足上述前置条件时才能使用双通道实验标定法标定。利用该方法对南京市气象局安装的拉曼激光雷达进行了光路测评和调整,并与CCD(charge-coupled device)侧向成像激光雷达观测信号做对比,结果显示调整后的定标效果更好。 相似文献
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Lidar has been used extensively in the area of atmospheric aerosol measurement. Two unknowns at the reference altitude, the lidar ratio and the backscatter coefficient, need to be resolved from the lidar equation. In the actual application, these two values are difficult to obtain, particularly the backscatter coefficient. To better characterize the optical properties of aerosols, optical thickness, and attenuated backscatter obtained by other instruments are usually used as the input for joint inversion. However, this method is limited by location and time. In this study, the authors propose a new method for aerosol retrieval by using Mie scatter- ing lidar data to solve this problem. The authors take the horizontal aerosol extinction coefficient as the con- straint to begin the iteration until a self-consistent aerosol vertical profile was obtained. By comparing their results with Aerosol Robotic Network （AERONET） data, the authours determine that the aerosol extinction coefficient obtained by combining horizontal and vertical lidar observations is more pre- cise than that obtained by using the traditional Fernald method. This new method has been adopted for re- trieving the extinction coefficient of aerosols during the observation days. 相似文献
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Sungkyun SHIN Young Min NOH Kwonho LEE Hanlim LEE Detlef MLLER Y.J.KIM Kwanchul KIM Dongho SHIN 《大气科学进展》2014,31(6):1417-1426
The vertical distribution of single scattering albedos （SSAs） of Asian dust mixed with pollutants was derived using the multi-wavelength Raman lidar observation system at Gwangju （35.10°N,126.53°E）.Vertical profiles of both backscatter and extinction coefficients for dust and non-dust aerosols were extracted from a mixed Asian dust plume using the depolarization ratio from lidar observations.Vertical profiles of backscatter and extinction coefficients of non-dust particles were input into an inversion algorithm to retrieve the SSAs of non-dust aerosols.Atmospheric aerosol layers at different heights had different light-absorbing characteristics.The SSAs of non-dust particles at each height varied with aerosol type,which was either urban/industrial pollutants from China transported over long distances at high altitude,or regional/local pollutants from the Korean peninsula.Taking advantage of independent profiles of SSAs of non-dust particles,vertical profiles of SSAs of Asian dust mixed with pollutants were estimated for the first time,with a new approach suggested in this study using an empirical determination of the SSA of pure dust.The SSAs of the Asian dust-pollutants mixture within the planetary boundary layer （PBL） were in the range 0.88-0.91,while the values above the PBL were in the range 0.76-0.87,with a very low mean value of 0.76 ± 0.05.The total mixed dust plume SSAs in each aerosol layer were integrated over height for comparison with results from the Aerosol Robotics Network （AERONET） measurements.Values of SSA retrieved from lidar observations of 0.92 ± 0.01 were in good agreement with the results from AERONET measurements. 相似文献
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Knowledge of the vertical distribution of aerosols in the free troposphere is important for estimating their impact on climate. In this study, direct observations of the vertical distribution of aerosols in the free troposphere are made using surface Micro-Pulse Lidar (MPL) measurements. The MPL measurements were made at the Loess Plateau (35.95°N, 104.1°E), which is near the major dust source regions of the Taklimakan and Gobi deserts. The vertical distribution of the MPL backscattering suggested that non-dust aerosols floated from ground level to an altitude of approximately 9 km around the source regions. Early morning hours are characterized by a shallow aerosol layer of a few hundred meters thick. As the day progresses, strong convective eddies transport the aerosols vertically to more than 1500 m.
Citation: Huang, J. P., Z. W. Huang, J. R. Bi, et al., 2008: Micro-pulse lidar measurements of aerosol vertical structure over the Loess Plateau, Atmos. Oceanic Sci. Lett., 1, 8-11 相似文献
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气溶胶激光雷达由于系统设计、观测场地气候条件、反演过程中参数选取等因素不同,每次测量反演得到的气溶胶光学参数质量不一致,可信度难以评估,进而极大地影响了其在气象、环保等领域业务化应用。为了解决该难题,本文分析了影响激光雷达气溶胶光学参数质量的因素,开发了一套气溶胶光学参数质量可信度评估算法。采用科学、合理的评分和权重分配方案对激光雷达每次测量反演得到的气溶胶光学参数质量可信度进行评估。本文主要讨论对偏振、米散射激光雷达气溶胶光学参数的质量评估,以中国气象局气象探测中心的波长为532 nm的偏振、米散射激光雷达为例,对所提出的质量可信度评估算法进行验证和分析。结果表明:该算法能够有效地区分出不同激光雷达在不同观测场景下每次测量反演得到的气溶胶光学参数质量可信度,具备为气溶胶激光雷达业务化应用提供可靠性评估的能力。 相似文献
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Mie 散射激光雷达探测大气气溶胶的进展 总被引：7，自引：1，他引：7
简要论述了激光雷达探测大气的优点,以及求解M ie散射激光雷达方程的理论方法,并阐述了国内外近20 a来M ie散射激光雷达探测大气气溶胶的主要成果,及其存在的问题。 相似文献
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CHEN Bin ZHANG Peng ZHANG Beidou JIA Rui ZHANG Zhijuan WANG Tianhe ZHOU Tian 《Acta Meteorologica Sinica》2014,28(6):1029-1040
In this paper, the methods to detect dust based on passive and active measurements from satellites have been summarized. These include the visible and infrared (VIR) method, thermal infrared (TIR) method, microwave polarized index (MPI) method, active lidar-based method, and combined lidar and infrared measurement (CLIM) method. The VIR method can identify dust during daytime. Using measurements at wavelengths of 8.5, 11.0, and 12.0 μm, the TIR method can distinguish dust from other types of aerosols and cloud, and identify the occurrence of dust over bright surfaces and during night. Since neither the VIR nor the TIR method can penetrate ice clouds, they cannot detect dust beneath ice clouds. The MPI method, however, can identify about 85% of the dust beneath ice clouds. Meanwhile, the active lidar-based method, which uses the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) data and five-dimensional probability distribution functions, can provide very high-resolution vertical profiles of dust aerosols. Nonetheless, as the signals from dense dust and thin clouds are similar in the CALIOP measurements, the lidar-based method may fail to distinguish between them, especially over dust source regions. To address this issue, the CLIM method was developed, which takes the advantages of both TIR measurements (to discriminate between ice cloud and dense dust layers) and lidar measurements (to detect thin dust and water cloud layers). The results obtained by using the new CLIM method show that the ratio of dust misclassification has been significantly reduced. Finally, a concept module for an integrated multi-satellites dust detection system was proposed to overcome some of the weaknesses inherent in the single-sensor dust detection. 相似文献
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Aerosols make a considerable contribution to the climate system through their radiative and cloud condensation nuclei effects, which underlines the need for understanding the origin of aerosols and their transport pathways. Seasonal distribution of mineral dust around the globe and its correlation with atmospheric circulation is investigated using satellite data, and meteorological data from ECMWF. The most important sources of dust are located in North Africa, the Middle East and Southwest Asia with an observed summer maximum, and East Asia with a spring peak. Maximum dust activity over North Africa and the Middle East in summer is attributed to dry convection associated with the summertime low-pressure system, while unstable weather and dry conditions are responsible for the spring peak in dust emission in East Asia. Intercontinental transport of mineral dust by atmospheric circulation has been observed, including trans-Atlantic transport of North African dust, trans-Pacific transport of Asian dust, and transport of dust from the Middle East across the Indian Ocean. The extent of African dust over the Atlantic Ocean and its latitudinal variation with season is related to the large-scale atmospheric circulation, including seasonal changes in the position of the intertropical convergence zone (ITCZ) and variation of wind patterns. North African aerosols extend over longer distances across the North Atlantic in summer because of greater dust emission, an intensified easterly low level jet (LLJ) and strengthening of the Azores-Bermuda anticyclonic circulation. Transport of East Asian aerosol is facilitated by the existence of a LLJ that extends from East Asia to the west coast of North America. 相似文献
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Ellsworth J. Welton Kenneth J. Voss Howard R. Gordon Hal Maring Alexander Smirnov Brent Holben Beat Schmid John M. Livingston Philip B. Russell Philip A. Durkee Paola Formenti Meinrat O. Andreae 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):636-651
A micro‐pulse lidar system (MPL) was used to measure the vertical and horizontal distribution of aerosols during the Aerosol Characterization Experiment 2 (ACE‐2) in June and July of 1997. The MPL measurements were made at the Izaña observatory (IZO), a weather station located on a mountain ridge (28°18' N, 16°30' W, 2367 m asl) near the center of the island of Tenerife, Canary Islands. The MPL was used to acquire aerosol backscatter, extinction, and optical depth profiles for normal background periods and periods influenced by Saharan dust from North Africa. System tests and calibration procedures are discussed, and an analysis of aerosol optical profiles acquired during ACE‐2 is presented. MPL data taken during normal IZO conditions (no dust) showed that upslope aerosols appeared during the day and dissipated at night and that the layers were mostly confined to altitudes a few hundred meters above IZO. MPL data taken during a Saharan dust episode on 17 July showed that peak aerosol extinction values were an order of magnitude greater than molecular scattering over IZO, and that the dust layers extended to 5 km asl. The value of the dust backscatter–extinction ratio was determined to be 0.027±0.007 sr−1 . Comparisons of the MPL data with data from other co‐located instruments showed good agreement during the dust episode. 相似文献
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2019年5月中旬,中国北方出现大范围沙尘暴天气,此次天气过程持续时间较长,影响范围较大。利用星载激光雷达CALIOP（Cloud-Aerosol Lidar with Orthogonal Polarization）和地基激光雷达AD-NET（Asian Dust and aerosol lidar observation NETwork）数据,对此次沙尘天气过程中沙尘气溶胶的分布特征以及沙尘传输过程进行分析;利用国家气象信息中心提供的小时天气实况数据对星载激光雷达资料以及后向轨迹模型HYSPLIT（the HYbird Single Particle Lagrangian Integrated Trajectory）得到的传输路径进行验证,同时结合空气质量数据分析此次天气过程对空气质量的影响;利用欧洲中心ERA-Interim再分析资料对此次沙尘天气成因进行分析。结果表明:（1）2019年5月10～16日沙尘天气主要分为两阶段,第一阶段为5月10～12日,第二阶段为13～16日。（2）通过CALIOP垂直特征层产品,发现在太平洋地区5～10 km的较高高度上,存在沙尘气溶胶,到达日本地区时,沙尘气溶胶的退偏比和色比平均值分别为0.14和1.29。（3）经过星载和地基激光雷达数据的综合分析,发现5月13～18日期间,沙尘气溶胶对日本长崎站点和韩国济州岛地基激光雷达站点的平均贡献率均值分别为42.16%和39.25%。（4）筛选了星载激光雷达经过日本和韩国站点的轨迹,对比分析两种数据的衰减后向散射系数以及表观散射比,发现两种数据的表观散射比廓线分布具有相近的变化趋势。（5）在沙尘天气期间,颗粒物浓度显著增加,PM10浓度最大值超过1500 μg m?3,是国家一级浓度标准的30倍;而5月11日PM2.5浓度在甘肃省最大,最大值达到国家一级浓度标准的7倍,14日最大值甚至达到12倍;PM10与PM2.5的浓度比值也在甘肃新疆多地达到6以上。（6）内蒙古西部的小槽的加深以及南压,使得西北冷空气稳定南下;在14日,不稳定层结加深导致沙尘天气再一次爆发。 相似文献
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By MATTHIAS TESCHE ALBERT ANSMANN DETLEF MÜLLER DIETRICH ALTHAUSEN INA MATTIS BIRGIT HEESE VOLKER FREUDENTHALER MATTHIAS WIEGNER MICHAEL ESSELBORN GIANLUCA PISANI PETER KNIPPERTZ 《Tellus. Series B, Chemical and physical meteorology》2009,61(1):144-164
Three ground-based Raman lidars and an airborne high-spectral-resolution lidar (HSRL) were operated during SAMUM 2006 in southern Morocco to measure height profiles of the volume extinction coefficient, the extinction-to-backscatter ratio and the depolarization ratio of dust particles in the Saharan dust layer at several wavelengths. Aerosol Robotic Network (AERONET) Sun photometer observations and radiosoundings of meteorological parameters complemented the ground-based activities at the SAMUM station of Ouarzazate. Four case studies are presented. Two case studies deal with the comparison of observations of the three ground-based lidars during a heavy dust outbreak and of the ground-based lidars with the airborne lidar. Two further cases show profile observations during satellite overpasses on 19 May and 4 June 2006. The height resolved statistical analysis reveals that the dust layer top typically reaches 4–6 km height above sea level (a.s.l.), sometimes even 7 km a.s.l.. Usually, a vertically inhomogeneous dust plume with internal dust layers was observed in the morning before the evolution of the boundary layer started. The Saharan dust layer was well mixed in the early evening. The 500 nm dust optical depth ranged from 0.2–0.8 at the field site south of the High Atlas mountains, Ångström exponents derived from photometer and lidar data were between 0–0.4. The volume extinction coefficients (355, 532 nm) varied from 30–300 Mm−1 with a mean value of 100 Mm−1 in the lowest 4 km a.s.l.. On average, extinction-to-backscatter ratios of 53–55 sr (±7–13 sr) were obtained at 355, 532 and 1064 nm. 相似文献
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A state-of-the art Rayleigh and Mie backscattering lidar was set up at Gadanki (13.5N, 79.2E) in the Tropics in India. Using this system, regular observations of upper tropospheric clouds, aerosols at stratospheric heights and atmospheric temperatures in the range from 30 to 80 km were made. In this paper, the data collected during the period of 1998–99 were selected for systematic investigation and presentation. The Mie scattering lidar system is capable of measuring the degree of depolarization in the laser backscattering. Several tropical cirrus cloud structures have been identified with low to moderate ice content. Occasionally, thin sub-visible cirrus clouds in the vicinity of the tropical tropopause have also been detected. The aerosol measurements in the upper troposphere and lower stratosphere show low aerosol content with a vertical distribution up to 35 km altitude. Rayleigh-scattering lidar observations reveal that at the tropical site, temperature inversion occurs at mesospheric heights. Atmospheric waves have induced perturbations in the temperatures for several times at the upper stratospheric heights. A significant warming in the lower mesosphere associated with a consistent cooling in the upper stratospheric heights is observed particularly in the winter season during the events of sudden stratospheric warming (SSW). 相似文献
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Assuming spheroidal and spherical particle shapes for mineral dust aerosols, the effect of particle shape on dust aerosol optical depth retrievals, and subsequently on instantaneous shortwave direct radiative forcing (SWDRF) at the top of the atmosphere (TOA), is assessed based on Moderate Resolution Imaging Spectroradiometer (MODIS) data for a case study. Specifically, a simplified aerosol retrieval algorithm based on the principle of the Deep Blue aerosol retrieval method is employed to retrieve dust aerosol optical depths, and the Fu-Liou radiative transfer model is used to derive the instantaneous SWDRF of dust at the TOA for cloud-free conditions. Without considering the effect of particle shape on dust aerosol optical depth retrievals, the effect of particle shape on the scattering properties of dust aerosols (e.g., extinction efficiency, single scattering albedo and asymmetry factor) is negligible, which can lead to a relative difference of at most 5% for the SWDRF at the TOA. However, the effect of particle shape on the SWDRF cannot be neglected provided that the effect of particle shape on dust aerosol optical depth retrievals is also taken into account for SWDRF calculations. The corresponding results in an instantaneous case study show that the relative differences of the SWDRF at the TOA between spheroids and spheres depend critically on the scattering angles at which dust aerosol optical depths are retrieved, and can be up to 40% for low dust-loading conditions. 相似文献
20.
Fabien Gibert Juan Cuesta Jun-Ichi Yano Nicolas Arnault Pierre H. Flamant 《Boundary-Layer Meteorology》2007,125(3):553-573
We question the correlation between vertical velocity (w) on the one hand and the occurrence of convective plumes in lidar reflectivity (i.e. range corrected backscatter signal Pz
2) and depolarization ratio (Δ) on the other hand in the convective boundary layer (CBL). Thermal vertical motion is directly
investigated using vertical velocities measured by a ground-based Doppler lidar operating at 2 μm. This lidar provides also
simultaneous measurements of lidar reflectivity. In addition, a second lidar 200 m away provides reflectivities at 0.53 and
1 μm and depolarization ratio at 0.53 μm. The time series from the two lidars are analyzed in terms of linear correlation
coefficient (ρ). The main result is that the plume-like structures provided by lidar reflectivity within the CBL as well as the CBL height
are not a clear signature of updrafts. It is shown that the lidar reflectivity within the CBL is frequently anti-correlated
(ρ (w, Pz
2 )) with the vertical velocity. On the contrary, the correlation coefficient between the depolarization ratio and the vertical
velocity ρ (w, Δ ) is always positive, showing that the depolarization ratio is a fair tracer of updrafts. The importance of relative humidity
on the correlation coefficient is discussed.
An erratum to this article can be found at 相似文献