Articles | Volume 12, issue 15
Research article 06 Aug 2012
Research article | 06 Aug 2012
Improvement of aerosol optical depth retrieval from MODIS spectral reflectance over the global ocean using new aerosol models archived from AERONET inversion data and tri-axial ellipsoidal dust database
J. Lee et al.
Related subject area
Subject: Aerosols | Research Activity: Remote Sensing | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)Satellite retrieval of aerosol combined with assimilated forecastA global analysis of diurnal variability in dust and dust mixture using CATS observationsSatellite-based radiative forcing by light-absorbing particles in snow across the Northern HemisphereConstraining the relationships between aerosol height, aerosol optical depth and total column trace gas measurements using remote sensing and modelsAerosol-enhanced high precipitation events near the Himalayan foothillsOptical characterization of pure pollen types using a multi-wavelength Raman polarization lidarMeasurement Report: Determination of aerosol vertical features on different timescales over East Asia based on CATS aerosol productsNorth African mineral dust sources: new insights from a combined analysis based on 3D dust aerosol distributions, surface winds and ancillary soil parametersEARLINET observations of Saharan dust intrusions over the northern Mediterranean region (2014–2017): properties and impact on radiative forcingElevated dust layers inhibit dissipation of heavy anthropogenic surface air pollutionBiomass burning events measured by lidars in EARLINET – Part 1: Data analysis methodologyStatistical aerosol properties associated with fire events from 2002 to 2019 along with a case analysis in 2019 over AustraliaAn AeroCom–AeroSat study: intercomparison of satellite AOD datasets for aerosol model evaluationRadiative effects of long-range-transported Saharan air layers as determined from airborne lidar measurementsAerosol type classification analysis using EARLINET multiwavelength and depolarization lidar observationsAutomated time-height-resolved airmass source attribution for profiling remote sensing applicationsLong-term multi-source data analysis about the characteristics of aerosol optical properties and types over AustraliaAerosol solar radiative forcing near the Taklimakan Desert based on radiative transfer and regional meteorological simulations during the Dust Aerosol Observation-Kashi campaignAn EARLINET early warning system for atmospheric aerosol aviation hazardsAerosol impacts on warm-cloud microphysics and drizzle in a moderately polluted environmentOptical properties of Central Asian aerosol relevant for spaceborne lidar applications and aerosol typing at 355 and 532 nmOptical and geometrical aerosol particle properties over the United Arab EmiratesDetermination and climatology of the diurnal cycle of the atmospheric mixing layer height over Beijing 2013–2018: lidar measurements and implications for air pollutionFirst validation of GOME-2/MetOp Absorbing Aerosol Height using EARLINET lidar observationsSite representativity of AERONET and GAW remotely sensed aerosol optical thickness and absorbing aerosol optical thickness observationsReducing uncertainties in satellite estimates of aerosol–cloud interactions over the subtropical ocean by integrating vertically resolved aerosol observationsRemote sensing of two exceptional winter aerosol pollution events and representativeness of ground-based measurementsComparison of south-east Atlantic aerosol direct radiative effect over clouds from SCIAMACHY, POLDER and OMI–MODISThe mechanisms and seasonal differences of the impact of aerosols on daytime surface urban heat island effectAn observational study of the effects of aerosols on diurnal variation of heavy rainfall and associated clouds over Beijing–Tianjin–HebeiLong-term profiling of aerosol light extinction, particle mass, cloud condensation nuclei, and ice-nucleating particle concentration over Dushanbe, Tajikistan, in Central AsiaSatellite mapping of PM2.5 episodes in the wintertime San Joaquin Valley: a “static” model using column water vaporImproved 1 km resolution PM2.5 estimates across China using enhanced space–time extremely randomized treesObservation of absorbing aerosols above clouds over the South-East Atlantic Ocean from the geostationary satellite SEVIRI – Part 2: Comparison with MODIS and aircraft measurements from the CLARIFY-2017 field campaignMerging regional and global aerosol optical depth records from major available satellite productsSatellite observations of aerosols and clouds over southern China from 2006 to 2015: analysis of changes and possible interaction mechanismsInterannual variability and trends of combustion aerosol and dust in major continental outflows revealed by MODIS retrievals and CAM5 simulations during 2003–2017Technical note: A simple method for retrieval of dust aerosol optical depth with polarized reflectance over oceansHow should we aggregate data? Methods accounting for the numerical distributions, with an assessment of aerosol optical depthConstraining global aerosol emissions using POLDER/PARASOL satellite remote sensing observationsDetection and characterization of birch pollen in the atmosphere using a multiwavelength Raman polarization lidar and Hirst-type pollen sampler in FinlandDifferent strategies to retrieve aerosol properties at night-time with the GRASP algorithmTwo-dimensional mineral dust radiative effect calculations from CALIPSO observations over EuropeInvestigation of CATS aerosol products and application toward global diurnal variation of aerosolsEARLINET evaluation of the CATS Level 2 aerosol backscatter coefficient productCharacterization of aerosol hygroscopicity using Raman lidar measurements at the EARLINET station of PayerneSatellite inference of water vapour and above-cloud aerosol combined effect on radiative budget and cloud-top processes in the southeastern Atlantic OceanRetrieval of ice-nucleating particle concentrations from lidar observations and comparison with UAV in situ measurementsComparison of two automated aerosol typing methods and their application to an EARLINET stationCloud macro-physical properties in Saharan-dust-laden and dust-free North Atlantic trade wind regimes: a lidar case study
Mayumi Yoshida, Keiya Yumimoto, Takashi M. Nagao, Taichu Y. Tanaka, Maki Kikuchi, and Hiroshi Murakami
Atmos. Chem. Phys., 21, 1797–1813,Short summary
We developed a new aerosol satellite retrieval algorithm combining a numerical aerosol forecast. This is the first study that utilizes the assimilated model forecast of aerosol as an a priori estimate of the retrieval. Aerosol retrievals were improved by effectively incorporating both model and satellite information. By using the assimilated forecast as an a priori estimate, information from previous observations can be propagated to future retrievals, thus leading to better retrieval accuracy.
Yan Yu, Olga V. Kalashnikova, Michael J. Garay, Huikyo Lee, Myungje Choi, Gregory S. Okin, John E. Yorks, James R. Campbell, and Jared Marquis
Atmos. Chem. Phys., 21, 1427–1447,Short summary
Given the current uncertainties in the simulated diurnal variability of global dust mobilization and concentration, observational characterization of the variations in dust mobilization and concentration will provide a valuable benchmark for evaluating and constraining such model simulations. The current study investigates the diurnal cycle of dust loading across the global tropics, subtropics, and mid-latitudes by analyzing aerosol observations from the International Space Station.
Jiecan Cui, Tenglong Shi, Yue Zhou, Dongyou Wu, Xin Wang, and Wei Pu
Atmos. Chem. Phys., 21, 269–288,Short summary
We make the first quantitative, remote-sensing-based, and hemisphere-scale assessment of radiative forcing (RF) due to light-absorbing particles (LAPs) in snow. We observed significant spatial variations in snow albedo reduction and RF due to LAPs throughout the Northern Hemisphere, with the lowest values occurring in the Arctic and the highest in northeastern China. We determined that the LAPs in snow play a critical role in spatial variability in Northern Hemisphere albedo reduction and RF.
Shuo Wang, Jason Blake Cohen, Chuyong Lin, and Weizhi Deng
Atmos. Chem. Phys., 20, 15401–15426,Short summary
We analyze global measurements of aerosol height from fires. A plume rise model reproduces measurements with a low bias in five regions, while a statistical model based on satellite measurements of trace gasses co-emitted from the fires reproduces measurements without bias in eight regions. We propose that the magnitude of the pollutants emitted may impact their height and subsequent downwind transport. Using satellite data allows better modeling of the global aerosol distribution.
Goutam Choudhury, Bhishma Tyagi, Naresh Krishna Vissa, Jyotsna Singh, Chandan Sarangi, Sachchida Nand Tripathi, and Matthias Tesche
Atmos. Chem. Phys., 20, 15389–15399,Short summary
This study uses 17 years (2001–2017) of observed rain rate, aerosol optical depth (AOD), meteorological reanalysis fields and outgoing long-wave radiation to investigate high precipitation events at the foothills of the Himalayas. Composite analysis of all data sets for high precipitation events (daily rainfall > 95th percentile) indicates clear and robust associations between high precipitation events, high aerosol loading and high moist static energy values.
Xiaoxia Shang, Elina Giannakaki, Stephanie Bohlmann, Maria Filioglou, Annika Saarto, Antti Ruuskanen, Ari Leskinen, Sami Romakkaniemi, and Mika Komppula
Atmos. Chem. Phys., 20, 15323–15339,Short summary
Measurements of the multi-wavelength Raman polarization lidar PollyXT have been combined with measurements of pollen type and concentration using a traditional pollen sampler at a rural forest site in Kuopio, Finland. The depolarization ratio was enhanced when there were pollen grains in the atmosphere, illustrating the potential of lidar to track pollen grains in the atmosphere. The depolarization ratio of pure pollen particles was assessed for birch and pine pollen using a novel algorithm.
Yueming Cheng, Tie Dai, Jiming Li, and Guangyu Shi
Atmos. Chem. Phys., 20, 15307–15322,Short summary
In this paper we present the analysis of the aerosol vertical features observed by CATS collected from 2015 to 2017 over three selected regions (North China, the Tibetan Plateau, and the Tarim Basin) over different timescales. This comprehensive information provides insights into the seasonal variations and diurnal cycles of the aerosol vertical features across East Asia.
Sophie Vandenbussche, Sieglinde Callewaert, Kerstin Schepanski, and Martine De Mazière
Atmos. Chem. Phys., 20, 15127–15146,Short summary
Mineral dust aerosols blown mostly from desert areas are a key player in the climate system. We use a new desert dust aerosol low-altitude concentration data set as well as additional information on the surface state and low-altitude winds to infer desert dust emission and source maps over North Africa. With 9 years of data, we observe a full seasonal cycle of dust emissions, differentiating morning and afternoon/evening emissions and providing a first glance at long-term changes.
Ourania Soupiona, Alexandros Papayannis, Panagiotis Kokkalis, Romanos Foskinis, Guadalupe Sánchez Hernández, Pablo Ortiz-Amezcua, Maria Mylonaki, Christina-Anna Papanikolaou, Nikolaos Papagiannopoulos, Stefanos Samaras, Silke Groß, Rodanthi-Elisavet Mamouri, Lucas Alados-Arboledas, Aldo Amodeo, and Basil Psiloglou
Atmos. Chem. Phys., 20, 15147–15166,Short summary
51 dust events over the Mediterranean from EARLINET were studied regarding the aerosol geometrical, optical and microphysical properties and radiative forcing. We found δp532 values of 0.24–0.28, LR532 values of 49–52 sr and AOT532 of 0.11–0.40. The aerosol mixing state was also examined. Depending on the dust properties, intensity and solar zenith angle, the estimated solar radiative forcing ranged from −59 to −22 W m−2 at the surface and from −24 to −1 W m−2 at the TOA (cooling effect).
Zhuang Wang, Cheng Liu, Zhouqing Xie, Qihou Hu, Meinrat O. Andreae, Yunsheng Dong, Chun Zhao, Ting Liu, Yizhi Zhu, Haoran Liu, Chengzhi Xing, Wei Tan, Xiangguang Ji, Jinan Lin, and Jianguo Liu
Atmos. Chem. Phys., 20, 14917–14932,Short summary
Significant stratification of aerosols was observed in North China. Polluted dust dominated above the PBL, and anthropogenic aerosols prevailed within the PBL, which is mainly driven by meteorological conditions. The key role of the elevated dust is to alter atmospheric thermodynamics and stability, causing the suppression of turbulence exchange and a decrease in PBL height, especially during the dissipation stage, thereby inhibiting dissipation of persistent heavy surface haze pollution.
Mariana Adam, Doina Nicolae, Iwona S. Stachlewska, Alexandros Papayannis, and Dimitris Balis
Atmos. Chem. Phys., 20, 13905–13927,Short summary
Biomass burning events measured by EARLINET are analysed using intensive parameters. The pollution layers are labelled smoke layers if fires were found along the air-mass back trajectory. The number of contributing fires to the smoke measurements is quantified. It is shown that most of the time we measure mixed smoke. The methodology provides three research directions: fires measured by several stations, long-range transport from N. America, and an analysis function of continental sources.
Xingchuan Yang, Chuanfeng Zhao, Yikun Yang, Xing Yan, and Hao Fan
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACP
Nick Schutgens, Andrew M. Sayer, Andreas Heckel, Christina Hsu, Hiren Jethva, Gerrit de Leeuw, Peter J. T. Leonard, Robert C. Levy, Antti Lipponen, Alexei Lyapustin, Peter North, Thomas Popp, Caroline Poulsen, Virginia Sawyer, Larisa Sogacheva, Gareth Thomas, Omar Torres, Yujie Wang, Stefan Kinne, Michael Schulz, and Philip Stier
Atmos. Chem. Phys., 20, 12431–12457,Short summary
We intercompare 14 different datasets of satellite observations of aerosol. Such measurements are challenging but also provide the best opportunity to globally observe an atmospheric component strongly related to air pollution and climate change. Our study shows that most datasets perform similarly well on a global scale but that locally errors can be quite different. We develop a technique to estimate satellite errors everywhere, even in the absence of surface reference data.
Manuel Gutleben, Silke Groß, Martin Wirth, and Bernhard Mayer
Atmos. Chem. Phys., 20, 12313–12327,Short summary
Airborne lidar measurements in the vicinity of Barbados are used to investigate radiative effects of long-range-transported Saharan air layers. Derived atmospheric heating rates indicate that observed enhanced water vapor concentrations inside these layers are the main drivers for dust vertical mixing inside the layers. Additionally, they may play a major role for the suppression of subjacent convective cloud development.
Maria Mylonaki, Elina Giannakaki, Alexandros Papayannis, Christina-Anna Papanikolaou, Mika Komppula, Doina Nicolae, Nikolaos Papagiannopoulos, Aldo Amodeo, Holger Baars, and Ourania Soupiona
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
We introduce an automated aerosol type classification method, SCAN. The output of SCAN is compared with two aerosol classification methods: (1) Mahalanobis distance automatic aerosol type classification and Neural Network Aerosol Typing Algorithm. A total of 97 free tropospheric aerosol layers from 4 EARLINET stations in the period 2014–2018 were classified.
Martin Radenz, Patric Seifert, Holger Baars, Athena Augusta Floutsi, Zhenping Yin, and Johannes Bühl
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACP
Xingchuan Yang, Chuanfeng Zhao, and Yikun Yang
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
We investigate the spatiotemporal distributions of aerosol optical properties and major aerosol types, along with the vertical distribution of the major aerosol types over Australia based on multi-source data. The results of this study provide significant information on aerosol optical properties in Australia, which can help understand the characteristics of aerosol optical properties in Australia along with their potential climate impacts.
Li Li, Zhengqiang Li, Wenyuan Chang, Yang Ou, Philippe Goloub, Chengzhe Li, Kaitao Li, Qiaoyun Hu, Jianping Wang, and Manfred Wendisch
Atmos. Chem. Phys., 20, 10845–10864,Short summary
Dust Aerosol Observation-Kashi (DAO-K) campaign was conducted near the Taklimakan Desert in April 2019 to obtain comprehensive aerosol, atmosphere, and surface parameters. Estimations of aerosol solar radiative forcing by a radiative transfer (RT) model were improved based on the measured aerosol parameters, additionally considering atmospheric profiles and diurnal variations of surface albedo. RT simulations agree well with simultaneous irradiance observations, even in dust-polluted conditions.
Nikolaos Papagiannopoulos, Giuseppe D'Amico, Anna Gialitaki, Nicolae Ajtai, Lucas Alados-Arboledas, Aldo Amodeo, Vassilis Amiridis, Holger Baars, Dimitris Balis, Ioannis Binietoglou, Adolfo Comerón, Davide Dionisi, Alfredo Falconieri, Patrick Fréville, Anna Kampouri, Ina Mattis, Zoran Mijić, Francisco Molero, Alex Papayannis, Gelsomina Pappalardo, Alejandro Rodríguez-Gómez, Stavros Solomos, and Lucia Mona
Atmos. Chem. Phys., 20, 10775–10789,Short summary
Volcanic and desert dust particles affect human activities in manifold ways; consequently, mitigation tools are important. Their early detection and the issuance of early warnings are key elements in the initiation of operational response procedures. A methodology for the early warning of these hazards using European Aerosol Research Lidar Network (EARLINET) data is presented. The tailored product is investigated during a volcanic eruption and mineral dust advected in the eastern Mediterranean.
Ying-Chieh Chen, Sheng-Hsiang Wang, Qilong Min, Sarah Lu, Pay-Liam Lin, Neng-Huei Lin, Kao-Shan Chung, and Everette Joseph
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
In this study, we integrate the satellite and surface observations to statistically quantify aerosol impacts on low-level warm cloud microphysics and drizzle over northern Taiwan. Our result provides observational evidence for aerosol indirect effects. The frequency of drizzle is reduced under polluted conditions. For light precipitation events (≤ 1 mm h−1), however, higher aerosol concentrations drive raindrops toward smaller sizes and thus increases the appearance of the drizzle drops.
Julian Hofer, Albert Ansmann, Dietrich Althausen, Ronny Engelmann, Holger Baars, Khanneh Wadinga Fomba, Ulla Wandinger, Sabur F. Abdullaev, and Abduvosit N. Makhmudov
Atmos. Chem. Phys., 20, 9265–9280,Short summary
For the first time, a dense data set of particle extinction-to-backscatter ratios (lidar ratios), depolarization ratios, and backscatter- and extinction-related Ångström exponents for a Central Asian site are presented. The observations were performed with a continuously running multiwavelength polarization Raman lidar at Dushanbe, Tajikistan, during an 18-month campaign. The found optical properties reflect the large range of occurring aerosol mixtures.
Maria Filioglou, Elina Giannakaki, John Backman, Jutta Kesti, Anne Hirsikko, Ronny Engelmann, Ewan O'Connor, Jari T. T. Leskinen, Xiaoxia Shang, Hannele Korhonen, Heikki Lihavainen, Sami Romakkaniemi, and Mika Komppula
Atmos. Chem. Phys., 20, 8909–8922,Short summary
Dust optical properties are region-dependent. Saharan, Asian, and Arabian dusts do not pose similar optical properties in terms of lidar ratios; thus, a universal lidar ratio for dust particles will lead to biases. The present study analyses observations over the United Arab Emirates, quantifying the optical and geometrical extents of the aerosol layers in the area, providing at the same time the Arabian dust properties along with chemical analysis of dust samples collected in the region.
Haofei Wang, Zhengqiang Li, Yang Lv, Ying Zhang, Hua Xu, Jianping Guo, and Philippe Goloub
Atmos. Chem. Phys., 20, 8839–8854,Short summary
Lidar shows good performance in calculating the convective layer height in the daytime and the residual layer height at night, as well as having the potential to describe the stable layer height at night. The MLH seasonal change in Beijing indicates that it is low in winter and autumn and high in spring and summer. From 2014 to 2018, the magnitude of the diurnal cycle of MLH increased year by year. MLH from lidar shows better accuracy than a radiosonde when calculating surface pollution.
Konstantinos Michailidis, Maria-Elissavet Koukouli, Nikolaos Siomos, Dimitrios Balis, Olaf Tuinder, L. Gijsbert Tilstra, Lucia Mona, Gelsomina Pappalardo, and Daniele Bortoli
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
The aim of this study is to investigate the potential of GOME-2 instrument on board the MetOpA, MetOpB and MetOpC platforms, to deliver accurate geometrical features of lofted aerosol layers. For this purpose, we use archived ground-based lidar data from lidar stations available from European Aerosol Research Lidar Network (EARLINET) database. We show that for, this well-developed and spatially well-spread aerosol layer, most GOME-2 retrievals fall within 1 km of the exactly temporally collocated.
Nick A. J. Schutgens
Atmos. Chem. Phys., 20, 7473–7488,Short summary
Aerosols are tiny particles in the air that affect human health and climate. To study these particles, measurement networks across the world are used. Each site, however, can only observe the air directly above it, so how representative is this measurement for the wider environment? The sites of a well-known remote sensing network (AERONET) are examined and ranked according to their representativity. This should benefit researchers using this measurement network.
David Painemal, Fu-Lung Chang, Richard Ferrare, Sharon Burton, Zhujun Li, William L. Smith Jr., Patrick Minnis, Yan Feng, and Marian Clayton
Atmos. Chem. Phys., 20, 7167–7177,Short summary
Aerosol–cloud interactions (ACIs) are the most uncertain aspect of anthropogenic forcing. Although satellites provide the observational dataset for the global ACI quantification, retrievals are limited to vertically integrated quantities (e.g., aerosol optical depth – AOD), which are typically used as an aerosol proxy. This study demonstrates that matching vertically resolved aerosol from CALIOP at the cloud-layer height with satellite cloud retrievals reduces uncertainties in ACI estimates.
Alexandre Baron, Patrick Chazette, and Julien Totems
Atmos. Chem. Phys., 20, 6749–6768,Short summary
Two major winter aerosol pollution events have been sampled over the Paris area. They correspond to weather conditions with a high-pressure system. We show that during such events the ground-based particle matter content can be related to lidar-derived aerosol extinction coefficient within the atmospheric planetary boundary layer. This opens a new horizon for the monitoring of intense pollution events from space-borne active sensors.
Martin de Graaf, Ruben Schulte, Fanny Peers, Fabien Waquet, L. Gijsbert Tilstra, and Piet Stammes
Atmos. Chem. Phys., 20, 6707–6723,Short summary
The radiative effect from smoke by wildfires has been found to be much stronger than models predict. The effect is complex; smoke generally cools the climate system by reflecting sunlight but strongly warms the system when it is found over a bright cloud deck. In this paper three different satellite datasets are compared and all three confirm the strong warming of African smoke over the cloud deck in the south-east Atlantic. The intercomparison reduces the uncertainties in the observations.
Wenchao Han, Zhanqing Li, Fang Wu, Yuwei Zhang, Jianping Guo, Tianning Su, Maureen Cribb, Jiwen Fan, Tianmeng Chen, Jing Wei, and Seoung-Soo Lee
Atmos. Chem. Phys., 20, 6479–6493,Short summary
Observational data and model simulation were used to analyze the daytime urban heat island intensity (UHII) under polluted and clean conditions in China. We found that aerosols reduce the UHII in summer but increase the UHII in winter. Two mechanisms, the aerosol radiative effect (ARE) and the aerosol dynamic effect (ADE), behave differently in summer and winter. In summer, the UHII is mainly affected by the ARE, and the ADE is weak, and the opposite is the case in winter.
Siyuan Zhou, Jing Yang, Wei-Chyung Wang, Chuanfeng Zhao, Daoyi Gong, and Peijun Shi
Atmos. Chem. Phys., 20, 5211–5229,Short summary
Aerosol–cloud–precipitation interaction is a challenging problem in regional climate. Our study contrasted the observed diurnal variation of heavy rainfall and associated clouds over Beijing–Tianjin–Hebei between clean and polluted days during the 2002–2012 summers. We found the heavy rainfall under pollution has earlier start time, earlier peak time and longer duration, and further found the absorbing aerosols and scattering aerosols play different roles in the heavy rainfall diurnal variation.
Julian Hofer, Albert Ansmann, Dietrich Althausen, Ronny Engelmann, Holger Baars, Sabur F. Abdullaev, and Abduvosit N. Makhmudov
Atmos. Chem. Phys., 20, 4695–4711,Short summary
For the first time, continuous, vertically resolved long-term aerosol measurements were conducted with a state-of-the-art multiwavelength lidar over a Central Asian site. Such observations are urgently required in efforts to predict future climate and environmental conditions and to support spaceborne remote sensing (ground truth activities).
Robert B. Chatfield, Meytar Sorek-Hamer, Robert F. Esswein, and Alexei Lyapustin
Atmos. Chem. Phys., 20, 4379–4397,Short summary
There is a great need to define health-affecting pollution by small particles as “respirable aerosol”. The wintertime San Joaquin Valley experiences severe episodes that need full maps. A few air pollution monitors are set out by agencies in such regions. Satellite data on haziness and daily calibration using the monitors map out improved pollution estimates for the winter of 2012–2013. These show patterns of valuable empirical information about sources, transport, and cleanout of pollution.
Jing Wei, Zhanqing Li, Maureen Cribb, Wei Huang, Wenhao Xue, Lin Sun, Jianping Guo, Yiran Peng, Jing Li, Alexei Lyapustin, Lei Liu, Hao Wu, and Yimeng Song
Atmos. Chem. Phys., 20, 3273–3289,Short summary
This study introduced an enhanced space–time extremely randomized trees (STET) approach to improve the 1 km resolution ground-level PM2.5 estimates across China using the remote sensing technology. The STET model shows high accuracy and strong predictive power and appears to outperform most models reported by previous studies. Thus, it is of great importance for future air pollution studies at medium- or small-scale areas and will be applied to generate the historical PM2.5 dataset across China.
Fanny Peers, Peter Francis, Steven J. Abel, Paul A. Barrett, Keith N. Bower, Michael I. Cotterell, Ian Crawford, Nicholas W. Davies, Cathryn Fox, Stuart Fox, Justin M. Langridge, Kerry G. Meyer, Steven E. Platnick, Kate Szpek, and Jim M. Haywood
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Satellite observations at high temporal resolution are a valuable asset to monitor the transport of biomass burning plumes and the cloud diurnal cycle in the South Atlantic, but they need to be validated. Cloud and above-cloud aerosol properties retrieved from SEVIRI are compared against MODIS and measurements from the CLARIFY-2017 campaign. While some systematic differences are observed between SEVIRI and MODIS, the overall agreement in the cloud and aerosol properties is very satisfactory.
Larisa Sogacheva, Thomas Popp, Andrew M. Sayer, Oleg Dubovik, Michael J. Garay, Andreas Heckel, N. Christina Hsu, Hiren Jethva, Ralph A. Kahn, Pekka Kolmonen, Miriam Kosmale, Gerrit de Leeuw, Robert C. Levy, Pavel Litvinov, Alexei Lyapustin, Peter North, Omar Torres, and Antti Arola
Atmos. Chem. Phys., 20, 2031–2056,Short summary
The typical lifetime of a single satellite platform is on the order of 5–15 years; thus, for climate studies the usage of multiple satellite sensors should be considered. Here we introduce and evaluate a monthly AOD merged product and AOD global and regional time series for the period 1995–2017 created from 12 individual satellite AOD products, which provide a long-term perspective on AOD changes over different regions of the globe.
Nikos Benas, Jan Fokke Meirink, Karl-Göran Karlsson, Martin Stengel, and Piet Stammes
Atmos. Chem. Phys., 20, 457–474,Short summary
In this study we analyse aerosol and cloud changes over southern China from 2006 to 2015 and investigate their possible interaction mechanisms. Results show decreasing aerosol loads and increasing liquid cloud cover in late autumn. Further analysis based on various satellite data sets shows consistency with the aerosol semi-direct effect, whereby less absorbing aerosols in the cloud layer would lead to an overall decrease in the evaporation of cloud droplets, thus increasing cloud amount.
Hongbin Yu, Yang Yang, Hailong Wang, Qian Tan, Mian Chin, Robert C. Levy, Lorraine A. Remer, Steven J. Smith, Tianle Yuan, and Yingxi Shi
Atmos. Chem. Phys., 20, 139–161,Short summary
Emissions and long-range transport of mineral dust and combustion-related aerosol from burning fossil fuels and biomass vary from year to year, driven by the evolution of the economy and changes in meteorological conditions and environmental regulations. This study offers both satellite and model perspectives on interannual variability and possible trends in combustion aerosol and dust in major continental outflow regions over the past 15 years (2003–2017).
Wenbo Sun, Yongxiang Hu, Rosemary R. Baize, Gorden Videen, Sungsoo S. Kim, Young-Jun Choi, Kyungin Kang, Chae Kyung Sim, Minsup Jeong, Ali Omar, Snorre A. Stamnes, David G. MacDonnell, and Evgenij Zubko
Atmos. Chem. Phys., 19, 15583–15586,Short summary
Dusts have a significant impact on climate and environment. Detecting dust using satellite instruments is generally conducted by measuring at multiple observation angles due to the uncertainty of the surface reflection. This report shows that the degree of polarization of reflected light can be used for retrieving the optical depth of dust at backscatter angles only, regardless of surface conditions. This simple method is suitable for surveying dust aerosols over oceans with low-cost satellites.
Andrew M. Sayer and Kirk D. Knobelspiesse
Atmos. Chem. Phys., 19, 15023–15048,Short summary
Data about the Earth are routinely obtained from satellite observations, model simulations, and ground-based or other measurements. These are at different space and timescales, and it is common to average them to reduce gaps and increase ease of use. The question of how the data should be averaged depends on the underlying distribution of the quantity. This study presents a method for determining how to appropriately aggregate data and applies it to data sets about atmospheric aerosol levels.
Cheng Chen, Oleg Dubovik, Daven K. Henze, Mian Chin, Tatyana Lapyonok, Gregory L. Schuster, Fabrice Ducos, David Fuertes, Pavel Litvinov, Lei Li, Anton Lopatin, Qiaoyun Hu, and Benjamin Torres
Atmos. Chem. Phys., 19, 14585–14606,Short summary
Global BC, OC and DD aerosol emissions are inverted from POLDER/PARASOL observations for the year 2010 based on the GEOS-Chem inverse modeling framework. The retrieved emissions are 18.4 Tg yr−1 BC, 109.9 Tg yr−1 OC and 731.6 Tg yr−1 DD, which indicate an increase of 166.7 % for BC and 184.0 % for OC, while a decrease of 42.4 % for DD with respect to GEOS-Chem a priori emission inventories is seen. Global annul mean AOD and AAOD resulting from retrieved emissions are 0.119 and 0.0071 at 550 nm.
Stephanie Bohlmann, Xiaoxia Shang, Elina Giannakaki, Maria Filioglou, Annika Saarto, Sami Romakkaniemi, and Mika Komppula
Atmos. Chem. Phys., 19, 14559–14569,Short summary
Measurements of the multiwavelength Raman polarization lidar PollyXT have been combined with measurements of pollen type and concentration using a traditional pollen sampler at the rural forest site in Vehmasmäki, Finland. High particle depolarization ratios were observed during an intense pollination event of birch pollen occasionally mixed with spruce pollen. Our observations illustrate the potential of the particle depolarization ratio to track pollen grains in the atmosphere.
Jose Antonio Benavent-Oltra, Roberto Román, Juan Andrés Casquero-Vera, Daniel Pérez-Ramírez, Hassan Lyamani, Pablo Ortiz-Amezcua, Andrés Esteban Bedoya-Velásquez, Gregori de Arruda Moreira, África Barreto, Anton Lopatin, David Fuertes, Milagros Herrera, Benjamin Torres, Oleg Dubovik, Juan Luis Guerrero-Rascado, Philippe Goloub, Francisco Jose Olmo-Reyes, and Lucas Alados-Arboledas
Atmos. Chem. Phys., 19, 14149–14171,Short summary
In this paper, we use the GRASP algorithm combining different remote-sensing measurements to obtain the aerosol vertical and column properties, both during the day and at night-time. The column properties are compared with AERONET products, and the vertical properties retrieved by GRASP are compared with in situ measurements at high-altitude stations. As an originality, we proposed three new schemes to retrieve the night-time aerosol properties.
Maria José Granados-Muñoz, Michaël Sicard, Nikolaos Papagiannopoulos, Rubén Barragán, Juan Antonio Bravo-Aranda, and Doina Nicolae
Atmos. Chem. Phys., 19, 13157–13173,Short summary
The use of satellite data is of great interest for the determination of aerosol radiative forcing at regional or even global scales, as previous studies in the literature are predominantly only valid locally. A methodology to retrieve 2-D dust radiative effects with large spatial and temporal coverage based on combined satellite data from CALIPSO, MODIS and CERES is presented and evaluated against well-established methods based on ground-based lidar measurements, obtaining quite good results.
Logan Lee, Jianglong Zhang, Jeffrey S. Reid, and John E. Yorks
Atmos. Chem. Phys., 19, 12687–12707,Short summary
The study of the diurnal variation of aerosol optical depth (AOD) and aerosol vertical distribution is necessary for the monitoring and modeling of aerosol particles for various air pollution, visibility and climate-related studies. Upon evaluating 1064 nm AOD and aerosol extinction profiles from the Cloud-Aerosol Transport System (CATS) level 2 aerosol product, we studied the diurnal variation of AOD and aerosol extinction profiles on both regional and global scales.
Emmanouil Proestakis, Vassilis Amiridis, Eleni Marinou, Ioannis Binietoglou, Albert Ansmann, Ulla Wandinger, Julian Hofer, John Yorks, Edward Nowottnick, Abduvosit Makhmudov, Alexandros Papayannis, Aleksander Pietruczuk, Anna Gialitaki, Arnoud Apituley, Artur Szkop, Constantino Muñoz Porcar, Daniele Bortoli, Davide Dionisi, Dietrich Althausen, Dimitra Mamali, Dimitris Balis, Doina Nicolae, Eleni Tetoni, Gian Luigi Liberti, Holger Baars, Ina Mattis, Iwona Sylwia Stachlewska, Kalliopi Artemis Voudouri, Lucia Mona, Maria Mylonaki, Maria Rita Perrone, Maria João Costa, Michael Sicard, Nikolaos Papagiannopoulos, Nikolaos Siomos, Pasquale Burlizzi, Rebecca Pauly, Ronny Engelmann, Sabur Abdullaev, and Gelsomina Pappalardo
Atmos. Chem. Phys., 19, 11743–11764,Short summary
To increase accuracy and validate satellite-based products, comparison with ground-based reference observations is required. To do this, we present evaluation activity of EARLINET for the qualitative and quantitative assessment of NASA's CATS lidar operating aboard the International Space Station (ISS) while identified discrepancies are discussed. Better understanding CATS performance and limitations provides a valuable basis for scientific studies implementing the satellite-based lidar system.
Francisco Navas-Guzmán, Giovanni Martucci, Martine Collaud Coen, María José Granados-Muñoz, Maxime Hervo, Michael Sicard, and Alexander Haefele
Atmos. Chem. Phys., 19, 11651–11668,Short summary
The present study demonstrates the capability of a Raman lidar to monitor aerosol hygroscopic processes. The results showed a higher hygroscopicity and wavelength dependency for smoke particles than for mineral dust. The higher sensitivity of the shortest wavelength to hygroscopic growth found for smoke particles was qualitatively reproduced using Mie simulations. The impact of aerosol hygroscopicity on the Earth's radiative balance has been evaluated using a radiative transfer model.
Lucia T. Deaconu, Nicolas Ferlay, Fabien Waquet, Fanny Peers, François Thieuleux, and Philippe Goloub
Atmos. Chem. Phys., 19, 11613–11634,Short summary
We analyse and quantify the effect of above-cloud aerosol (AAC) loading on the underlying cloud properties in the South Atlantic Ocean. We use a synergy of remote sensing retrievals collocated with ERA-Interim meteorological profiles. The results show that for larger loads of AACs, clouds are optically thicker, with an increase in liquid water path by 20 g m−2 and lower cloud-top altitudes. We also observe a strong covariation between the aerosol plume and the presence of water vapour.
Eleni Marinou, Matthias Tesche, Athanasios Nenes, Albert Ansmann, Jann Schrod, Dimitra Mamali, Alexandra Tsekeri, Michael Pikridas, Holger Baars, Ronny Engelmann, Kalliopi-Artemis Voudouri, Stavros Solomos, Jean Sciare, Silke Groß, Florian Ewald, and Vassilis Amiridis
Atmos. Chem. Phys., 19, 11315–11342,Short summary
We assess the feasibility of ground-based and spaceborne lidars to retrieve profiles of cloud-relevant aerosol concentrations and ice-nucleating particles. The retrieved profiles are in good agreement with airborne in situ measurements. Our methodology will be applied to satellite observations in the future so as to provide a global 3D product of cloud-relevant properties.
Kalliopi Artemis Voudouri, Nikolaos Siomos, Konstantinos Michailidis, Nikolaos Papagiannopoulos, Lucia Mona, Carmela Cornacchia, Doina Nicolae, and Dimitris Balis
Atmos. Chem. Phys., 19, 10961–10980,Short summary
In this study, a first attempt at comparing and evaluating two classification tools developed within EARLINET that provide near-real-time aerosol typing information for the lidar profiles of Thessaloniki is presented. Our aim is (i) to check the performance of both supervised learning techniques in their low-resolution mode and (ii) to investigate the reasons for typing agreement and disagreement with respect to the uncertainties and the threshold criteria applied.
Manuel Gutleben, Silke Groß, and Martin Wirth
Atmos. Chem. Phys., 19, 10659–10673,Short summary
This study concentrates on airborne lidar measurements conducted during the NARVAL field experiments over the western subtropical North Atlantic Ocean to study differences between shallow marine cloud macro-physical properties (i.e. cloud fraction, cloud top height, cloud length, cloud gap length) in Saharan-dust-laden and dust-free trade wind regions. Cloud top heights, cloud fractions and cloud lengths are found to be lower and smaller in Saharan-dust-laden compared to dust-free regions.
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