scholarly journals Aerosol optical properties variability during biomass burning events observed by the eole-aias depolarization lidars over Athens, Greece (2007-2016)

2018 ◽  
Vol 176 ◽  
pp. 05022
Author(s):  
Maria Mylonaki ◽  
Alexandros Papayannis ◽  
Rodanthi Mamouri ◽  
Athina Argyrouli ◽  
Panagiotis Kokkalis ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Vertical Profiles ◽  
Aerosol Optical Properties ◽  
Smoke Particles ◽  
Range Transport ◽  
Multi Wavelength ◽  
Lidar Ratio ◽  
Sun Photometer ◽  
532 Nm

The EOLE multi-wavelength aerosol Ramandepolarization lidar, and the AIAS depolarization lidar, in synergy with a sun photometer (CIMEL), were used, in the period 2007-2016, to provide the vertical profiles of the aerosol optical properties over Athens, Greece. More than 30 biomass burning events (fresh and aged smoke particles) were observed, with smoke layers between 1.5 up to 4-5 km height, while their duration ranged from 1-3 days. Lidar ratio (LR) values ranged from 40-105 sr (at 355 nm) and from 40-100 sr (at 532 nm), while the linear particle depolarization ratio (LPDR) at both 355 and 532 nm, remained <7%. The extinction-related Ångström exponent (AEa) at 355 nm/532 nm) ranged from 0.3 to 2.1. Additionally, a case of a near-range transport of biomass burning aerosols arriving over Athens up to 4 km height, between 27 and 28 June 2016, was studied. For this case, we found LRs of the order of 70±5 sr (355 nm) and 65±15 sr (532 nm) and AEa(355 nm/532 nm) around 1.

scholarly journals Insights into the aging of biomass burning aerosol from satellite observations and 3D atmospheric modeling: evolution of the aerosol optical properties in Siberian wildfire plumes

2021 ◽  
Vol 21 (1) ◽  
pp. 357-392
Author(s):  
Igor B. Konovalov ◽  
Nikolai A. Golovushkin ◽  
Matthias Beekmann ◽  
Meinrat O. Andreae
Keyword(s):  
Optical Properties ◽  
Long Range ◽  
Biomass Burning ◽  
Organic Aerosol ◽  
Satellite Observations ◽  
Long Range Transport ◽  
Aerosol Optical Properties ◽  
Smoke Plumes ◽  
Range Transport ◽  
Aerosol Aging

Abstract. Long-range transport of biomass burning (BB) aerosol from regions affected by wildfires is known to have a significant impact on the radiative balance and air quality in receptor regions. However, the changes that occur in the optical properties of BB aerosol during long-range transport events are insufficiently understood, limiting the adequacy of representations of the aerosol processes in chemistry transport and climate models. Here we introduce a framework to infer and interpret changes in the optical properties of BB aerosol from satellite observations of multiple BB plumes. Our framework includes (1) a procedure for analysis of available satellite retrievals of the absorption and extinction aerosol optical depths (AAOD and AOD) and single-scattering albedo (SSA) as a function of the BB aerosol photochemical age and (2) a representation of the AAOD and AOD evolution with a chemistry transport model (CTM) involving a simplified volatility basis set (VBS) scheme with a few adjustable parameters. We apply this framework to analyze a large-scale outflow of BB smoke plumes from Siberia toward Europe that occurred in July 2016. We use AAOD and SSA data derived from OMI (Ozone Monitoring Instrument) satellite measurements in the near-UV range along with 550 nm AOD and carbon monoxide (CO) columns retrieved from MODIS (Moderate Resolution Imaging Spectroradiometer) and IASI (Infrared Atmospheric Sounding Interferometer) satellite observations, respectively, to infer changes in the optical properties of Siberian BB aerosol due to its atmospheric aging and to get insights into the processes underlying these changes. Using the satellite data in combination with simulated data from the CHIMERE CTM, we evaluate the enhancement ratios (EnRs) that allow isolating AAOD and AOD changes due to oxidation and gas–particle partitioning processes from those due to other processes, including transport, deposition, and wet scavenging. The behavior of EnRs for AAOD and AOD is then characterized using nonlinear trend analysis. It is found that the EnR for AOD strongly increases (by about a factor of 2) during the first 20–30 h of the analyzed evolution period, whereas the EnR for AAOD does not exhibit a statistically significant increase during this period. The increase in AOD is accompanied by a statistically significant enhancement of SSA. Further BB aerosol aging (up to several days) is associated with a strong decrease in EnRs for both AAOD and AOD. Our VBS simulations constrained by the observations are found to be more consistent with satellite observations of strongly aged BB plumes than “tracer” simulations in which atmospheric transformations of BB organic aerosol were disregarded. The simulation results indicate that the upward trends in EnR for AOD and in SSA are mainly due to atmospheric processing of secondary organic aerosol (SOA), leading to an increase in the mass scattering efficiency of BB aerosol. Evaporation and chemical fragmentation of the SOA species, part of which is assumed to be absorptive (to contain brown carbon), are identified as likely reasons for the subsequent decrease in the EnR for both AAOD and AOD. Hence, our analysis reveals that the long-range transport of smoke plumes from Siberian fires is associated with major changes in BB aerosol optical properties and chemical composition. Overall, this study demonstrates the feasibility of using available satellite observations for evaluating and improving representations in atmospheric models of the BB aerosol aging processes in different regions of the world at much larger temporal scales than those typically addressed in aerosol chamber experiments.

scholarly journals Biomass burning events measured by lidars in EARLINET. Part II. Results and discussions

2020 ◽  
Author(s):  
Mariana Adam ◽  
Doina Nicolae ◽  
Livio Belegante ◽  
Iwona S. Stachlewska ◽  
Lucja Janicka ◽  
...  
Keyword(s):  
North America ◽  
Long Range ◽  
Biomass Burning ◽  
Long Range Transport ◽  
Depolarization Ratio ◽  
Smoke Particles ◽  
Geographical Regions ◽  
Range Transport ◽  
Ångström Exponent ◽  
Lidar Ratio

Abstract. Biomass burning events are analysed using the European Aerosol Research Lidar Network database for atmospheric profiling of aerosols by lidars. Atmospheric profiles containing forest fires layers were identified in data collected by fourteen stations during 2008–2017. The data ranged from complete data sets (particle backscatter coefficient, extinction coefficient and linear depolarization ratio) to single profiles (particle backscatter coefficient). The data analysis methodology was described in Part I (Biomass burning events measured by lidars in EARLINET. Part I. Data analysis methodology, under discussions to ACP, the EARLINET special issue). The results are analysed by means of intensive parameters in three directions: (I) common biomass burning source (fire) recorded by at least two stations, (II) long range transport of smoke particles from North America (here, we divided the events into pure North America and mixed-North America and local) smoke groups, and (III) analysis of smoke particles over four geographical regions (SE Europe, NE Europe, Central Europe and SW Europe). Five events were found for case (I), while 24 events were determined for case (II). A statistical analysis over the four geographical regions considered revealed that smoke originated from different regions. The smoke detected in the Central Europe region (Cabauw, Leipzig, and Hohenpeißenberg) was mostly brought over from North America (87 % of the fires), by long range transport. The smoke in the South West region (Barcelona, Evora, and Granada) came mostly from the Iberian Peninsula and North Africa, the long-range transport from North America accounting for only 9 % here. The smoke in the North Europe region (Belsk, Minsk, and Warsaw) originated mostly in East Europe (Ukraine and Russia), and had a 31 % contribution from smoke by long-range transport from North America. For the South East region (Athens, Bucharest, Potenza, Sofia, Thessaloniki) the origin of the smoke was mostly located in SE Europe (only 3 % from North America). Specific features for the lidar-derived intensive parameters based on smoke continental origin were determined for each region. Based on the whole dataset, the following signatures were observed: (i) the colour ratio of the lidar ratio and the backscatter Ångström exponent increase with travel time, while the extinction Ångström exponent and the colour ratio of the particle depolarization ratio decrease; (ii) an increase of the colour ratio of the particle depolarization ratio corresponds to both a decrease of the colour ratio of the lidar ratios and an increase of the extinction Ångström exponent; (iii) the measured smoke originating from all continental regions is characterized in average as aged smoke, except for a few cases; (iv) in general, the local smoke shows a smaller lidar ratio while the long range transported smoke shows a higher lidar ratio; and (v) the depolarization is smaller for long range transported smoke. A complete characterization of the smoke particles type (either fresh or aged) is presented for each of the four geographical regions versus different continental source regions.

scholarly journals Seventeen-year systematic measurements of dust aerosol optical properties using the eole ntua lidar system (2000-2016)

2018 ◽  
Vol 176 ◽  
pp. 05029
Author(s):  
Ourania Soupiona ◽  
Maria Mylonaki ◽  
Alexandros Papayannis ◽  
Athina Argyrouli ◽  
Panayotis Kokkalis ◽  
...  
Keyword(s):  
Optical Properties ◽  
Mean Value ◽  
Saharan Dust ◽  
Aerosol Optical Properties ◽  
Mean Values ◽  
Time Period ◽  
Lidar Measurements ◽  
Multi Wavelength ◽  
Lidar Ratio ◽  
Dust Events

A comprehensive analysis of the seasonal variability of the optical properties of Saharan dust aerosols over Athens, Greece, is presented for a 17-year time period (2000-2016), as derived from multi-wavelength Raman lidar measurements (57 dust events with more than 80 hours of measurements). The profiles of the derived aerosol optical properties (aerosol backscatter and extinction coefficients, lidar ratio and aerosol Ångström exponent) at 355 nm are presented. For these dust events we found a mean value of the lidar ratio of ~52±13 sr at 355 nm and of ~58±8 sr (not shown) at 532 nm (2-4 km a.s.l. height). For our statistical analysis, presented here, we used monthly-mean values and time periods under cloud-free conditions. The number of dust events was greatest in late spring, summer, and early autumn periods. In this paper we also present a selected case study (04 April 2016) of desert dust long-range transport from the Saharan desert.

scholarly journals Optical and microphysical characterization of aerosol layers over South Africa by means of multi-wavelength depolarization and Raman lidar measurements

2015 ◽  
Vol 15 (23) ◽  
pp. 35237-35276
Author(s):  
E. Giannakaki ◽  
P. G. van Zyl ◽  
D. Müller ◽  
D. Balis ◽  
M. Komppula
Keyword(s):  
South Africa ◽  
Biomass Burning ◽  
Single Scattering ◽  
Effective Radius ◽  
Depolarization Ratio ◽  
Raman Lidar ◽  
Desert Dust ◽  
Multi Wavelength ◽  
Lidar Ratio ◽  
532 Nm

Abstract. Optical and microphysical properties of different aerosol types over South Africa measured with a multi-wavelength polarization Raman lidar are presented. This study could assist in bridging existing gaps relating to aerosol properties over South Africa, since limited long-term data of this type is available for this region. The observations were performed under the framework of the EUCAARI campaign in Elandsfontein. The multi-wavelength PollyXT Raman lidar system was used to determine vertical profiles of the aerosol optical properties, i.e. extinction and backscatter coefficients, Ångström exponents, lidar ratio and depolarization ratio. The mean microphysical aerosol proper ties, i.e. effective radius and single scattering, albedo were retrieved with an advanced inversion algorithm. Clear differences were observed for the intensive optical properties of atmospheric layers of biomass burning and urban/industrial aerosols. Our results reveal a wide range of optical and microphysical parameters for biomass burning aerosols. This indicates probable mixing of biomass burning aerosols with desert dust particles, as well as the possible continuous influence of urban/industrial aerosol load in the region. The lidar ratio at 355 nm, the linear particle depolarization ratio at 355 nm and the extinction-related Ångström exponent from 355 to 532 nm were 52 ± 7 sr; 0.9 ± 0.4 % and 2.3 ± 0.5, respectively for urban/industrial aerosols, while these values were 92 ± 10 sr; 3.2 ± 1.3 %; 2.0 ± 0.4 respectively for biomass burning aerosols layers. Biomass burning particles are larger and slightly less absorbing compared to urban/industrial aerosols. The particle effective radius were found to be 0.10 ± 0.03, 0.17 ± 0.04 and 0.13 ± 0.03 μm for urban/industrial, biomass burning, and mixed biomass burning and desert dust aerosols, respectively, while the single scattering albedo at 532 nm were 0.87 ± 0.06, 0.90 ± 0.06, and 0.88 ± 0.07 (at 532 nm), respectively for these three types of aerosols. Our results were within the same range of previously reported values.

scholarly journals Insights into the aging of biomass burning aerosol from satellite observations and 3D atmospheric modeling: Evolution of the aerosol optical properties in Siberian wildfire plumes

2020 ◽  
Author(s):  
Igor B. Konovalov ◽  
Nikolai A. Golovushkin ◽  
Matthias Beekmann ◽  
Meinrat O. Andreae
Keyword(s):  
Optical Properties ◽  
Long Range ◽  
Biomass Burning ◽  
Satellite Observations ◽  
The Arctic ◽  
Long Range Transport ◽  
Aerosol Optical Properties ◽  
Smoke Plumes ◽  
Range Transport ◽  
Aerosol Aging

Abstract. Long-range transport of biomass burning (BB) aerosol from regions affected by wildfires is known to have a significant impact on the radiative balance and air quality in receptor regions, including the Arctic. However, the atmospheric evolution of the optical properties of BB aerosol during the long-range transport events is insufficiently understood, limiting the adequacy of representations of the aerosol processes in chemistry transport and climate models. Here we introduce a framework to infer and interpret changes of the optical properties of BB aerosol from satellite observations of multiple BB plumes. Our framework includes (1) a procedure for analysis of available satellite retrievals of the absorption and extinction aerosol optical depths (AAOD and AOD) and single scattering albedo (SSA) as a function of the BB aerosol photochemical age, and (2) a representation of the AAOD and AOD evolution with a chemistry transport model (CTM) involving a simplified volatility basis set (VBS) scheme with a few adjustable parameters. We apply this framework to analyze a large-scale outflow of BB smoke plumes from Siberia toward Europe that occurred in July 2016. We use AAOD and SSA data derived from OMI (Ozone Monitoring Instrument) satellite measurements in the near-UV range along with 550 nm AOD and carbon monoxide (CO) columns retrieved from MODIS (Moderate Resolution Imaging Spectroradiometer) and IASI (Infrared Atmospheric Sounding Interferometer) satellite observations, respectively, to infer changes in the optical properties of Siberian BB aerosol due to its atmospheric aging and to get insights into the processes underlying these changes. Using the satellite data in combination with simulated data from the CHIMERE CTM, we evaluate the enhancement ratios (EnR) that allow isolating AAOD and AOD changes due to oxidation and gas-particle partitioning processes from those due to other processes, including transport, deposition, and wet scavenging. The behavior of EnRs for AAOD and AOD is then characterized using nonlinear trend analysis. It is found that the EnR for AOD strongly increases (by about a factor of 2) during the first 20–30 hours of the analyzed evolution period, whereas the EnR for AAOD does not exhibit a statistically significant increase during this period. The increase in AOD is accompanied by a statistically significant enhancement of SSA. Further BB aerosol aging (up to several days) is associated with a strong decrease of EnRs for both AAOD and AOD. Our simulations constrained by the observations indicate that the upward trends in EnR for AOD and in SSA are mainly due to atmospheric processing of secondary organic aerosol (SOA), leading to an increase in the mass scattering efficiency of BB aerosol. Evaporation and chemical fragmentation of the SOA species, part of which is assumed to be absorptive (to contain brown carbon), are identified as a likely reason for the subsequent decrease of the EnR for both AAOD and AOD. Hence, our analysis reveals that the long-range transport of smoke plumes from Siberian fires is associated with major changes in BB aerosol optical properties and chemical composition. Overall, this study demonstrates the feasibility of using available satellite observations for evaluating and improving representations in atmospheric models of the BB aerosol aging processes in different regions of the world at much larger temporal scales than those typically addressed in aerosol chamber experiments.

scholarly journals Canadian biomass burning aerosols observations from a multi-wavelength Raman polarization lidar and a ceilometer in Finland

2021 ◽  
Author(s):  
Xiaoxia Shang ◽  
Tero Mielonen ◽  
Antti Lipponen ◽  
Elina Giannakaki ◽  
Ari Leskinen ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Mass Concentration ◽  
Lower Troposphere ◽  
Dust Particles ◽  
Backscatter Coefficient ◽  
Smoke Particles ◽  
Multi Wavelength ◽  
532 Nm ◽  
Mass Concentrations ◽  
Depolarization Ratios

Abstract. Layers of biomass burning aerosol particles were observed in the lower troposphere, at 2 to 5 km height on 4 to 6 June 2019, over Kuopio, Finland. These long-range-transported smoke particles originated from a Canadian wildfire event. The most pronounced smoke plume detected on 5 June was intensively investigated. Optical properties were retrieved from the multi-wavelength Raman polarization lidar PollyXT. Particle linear depolarization ratios of this plume were measured to be 0.08 ± 0.02 at 355 nm and 0.05 ± 0.01 at 532 nm which were slightly higher than the values given in the literature. Non-spherical shaped aged smoke particles and/or the mixing with a small amount of fine dust particles could cause the observed increase in the particle linear depolarization ratios. Lidar ratios were derived as 47 ± 5 sr at 355 nm and 71 ± 5 sr at 532 nm. A complete ceilometer data processing for a Vaisala CL51 is presented, including the water vapor correction for high latitude for the first time, from sensor provided attenuated backscatter coefficient to particle mass concentration. A combined lidar and sun-photometer approach (based on AERONET products) is applied for mass concentration estimations. Mass concentrations were estimated from both PollyXT and the ceilometer CL51 observations, which were of the order of ~ 30 µg m−3 in the morning and decreased to ~ 20 µg m−3 in the night. A difference of ~ 30% was found between PollyXT and CL51 estimated mass concentrations. The mass retrievals were discussed and compared with the Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) meteorological and aerosol reanalysis. The inclusion of dust in the retrieved mass concentration slightly improved the correspondence between the observations and the MERRA-2 simulations.

scholarly journals Calibration and retrieval of aerosol optical properties measured with Coherent Doppler Lidar

2021 ◽  
Author(s):  
Guangyao Dai ◽  
Xiaoye Wang ◽  
Kangwen Sun ◽  
Songhua Wu ◽  
Xiaoquan Song ◽  
...  
Keyword(s):  
Optical Properties ◽  
Field Experiments ◽  
Practical Method ◽  
Doppler Lidar ◽  
Aerosol Optical Properties ◽  
Backscatter Signal ◽  
Coherent Doppler Lidar ◽  
Comparison Results ◽  
Multi Wavelength ◽  
Sun Photometer

AbstractA practical method for instrumental calibration and aerosol optical properties retrieval based on Coherent Doppler Lidar (CDL) and sun-photometer is presented in this paper. To verify its feasibility and accuracy, this method is applied into three field experiments in 2019 and 2020. In this method, multi-wavelength (440 nm, 670 nm, 870 nm and 1020 nm) Aerosol Optical Depth (AOD) from sun-photometer measurements are used to estimate AOD at 1550 nm and calibrate integrated CDL backscatter signal. Then, it is validated by comparing the retrieved calibrated AOD at 1550 nm from CDL signal and that from sun-photometer measurements. Well agreement between them with the correlation of 0.96, the RMSE of 0.0085 and the mean relative error of 22% is found. From the comparison results of these three experiments, sun-photometer is verified to be an effective reference instrument for the calibration of CDL return signal and the aerosol optical properties measurement with CDL is feasible. It is expected to promote the study on the aerosol flux and transport mechanism in the planetary boundary layer with the widely deployed CDLs.

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