Observations of California forest fire aerosol in Potenza (Italy) by the multi-wavelength Raman lidar MUSA

2021 ◽  
Author(s):  
Benedetto De Rosa ◽  
Lucia Mona ◽  
Aldo Amodeo ◽  
Donato Summa
Keyword(s):  
Optical Properties ◽  
Real Time ◽  
Forest Fire ◽  
Radiative Forcing ◽  
Vertical Structure ◽  
Back Trajectory ◽  
Free Troposphere ◽  
Raman Lidar ◽  
Smoke Particles ◽  
Fire Smoke

<p>Smoke aerosols play an important role in the atmospheric chemistry in terms of direct and indirect radiative forcing. Despite this, their properties in free troposphere and stratosphere are still insufficiently studied. When the smoke reaches these altitudes can be transported over transcontinental distances. During the transport of particles important transforming processes, such as coagulation, condensation, and gas-to-particle conversion occur, thus affecting environment and climate. The optical properties of smoke plumes have been usually analyzed by ground-based radiometers and satellite. However, these techniques cannot characterize accurately the high variability of the vertical structure of smoke aerosol. Raman lidar systems  are characterized by high temporal and vertical resolutions and have demonstrated a strong capability to study long-range transport, optical properties and vertical structure of forest fire smoke. </p><p>In the 2020 California’s fire season was exceptionally catastrophic. 23<sup>rd </sup>October, the immense Sonoma fire, in few days scorched 31000 hectares. The deep convection lifted the smoke from these fires to great heights. After reaching the free troposphere and stratosphere, the forest fire smoke was transported over great distances and reached the south of Italy, as evinced by the map of biomass burning aerosol optical depth at 550 nm, provided by the Copernicus Atmosphere Monitoring Service (CAMS).</p><p>This work reports measurements carried out in the frame of the project CAMS21b by the Raman lidar system MUSA deployed at CNR-IMAA Atmospheric Observatory (CIAO) in Potenza. CAMS21b aims to design, test and set up the provisioning to CAMS of ACTRIS/EARLINET products in real time and near real time. </p><p>In the case study of 26 October 2020, from to 10:13 to 13:45 UTC, measurements of particle backscattering coefficient at 355, 532 nm and 1064 and of the particle extinction coefficient at 355 nm and 532nm, show the presence of two distinct aerosol layers. A lower one extending from 6 km to 8 km and an upper one extending from 10 km to 12 km. The back-trajectory analysis reveals that the air masses originated over California, overpassed the Atlantic sea before reaching the measurement site.</p><p>The values of the particle depolarization ratio are similar to those found in literature for smoke aerosols. In the first layer, values lower than 0.05 are indicative for small and spherical smoke particles. The moderately increased depolarization ratios in the second layer indicate the possible presence of partly coated smoke particles.</p><p>More results from this measurement effort will be reported and discussed at the Conference.</p>

scholarly journals Forest Fire Smoke Layers Observed in the Free Troposphere over Portugal with a Multiwavelength Raman Lidar: Optical and Microphysical Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Sérgio Nepomuceno Pereira ◽  
Jana Preißler ◽  
Juan Luis Guerrero-Rascado ◽  
Ana Maria Silva ◽  
Frank Wagner
Keyword(s):  
Single Scattering ◽  
Effective Radius ◽  
Free Troposphere ◽  
Depolarization Ratio ◽  
Raman Lidar ◽  
Extinction Coefficients ◽  
Smoke Particles ◽  
Microphysical Properties ◽  
Fire Smoke ◽  
Lidar Ratio

Vertically resolved optical and microphysical properties of biomass burning aerosols, measured in 2011 with a multiwavelength Raman lidar, are presented. The transportation time, within 1-2 days (or less), pointed towards the presence of relatively fresh smoke particles over the site. Some strong layers aloft were observed with particle backscatter and extinction coefficients (at 355 nm) greater than 5 Mm−1 sr−1and close to 300 Mm−1, respectively. The particle intensive optical properties showed features different from the ones reported for aged smoke, but rather consistent with fresh smoke. The Ångström exponents were generally high, mainly above 1.4, indicating a dominating accumulation mode. Weak depolarization values, as shown by the small depolarization ratio of 5% or lower, were measured. Furthermore, the lidar ratio presented no clear wavelength dependency. The inversion of the lidar signals provided a set of microphysical properties including particle effective radius below 0.2 μm, which is less than values previously observed for aged smoke particles. Real and imaginary parts of refractive index of about 1.5-1.6 and 0.02i, respectively, were derived. The single scattering albedo was in the range between 0.85 and 0.93; these last two quantities indicate the nonnegligible absorbing characteristics of the observed particles.

scholarly journals Wildfire particulate matter in Europe during summer 2003: meso-scale modeling of smoke emissions, transport and radiative effects

2007 ◽  
Vol 7 (2) ◽  
pp. 4705-4760 ◽  
Author(s):  
A. Hodzic ◽  
S. Madronich ◽  
B. Bohn ◽  
S. Massie ◽  
L. Menut ◽  
...  
Keyword(s):  
Optical Properties ◽  
Air Quality ◽  
Radiative Forcing ◽  
Anthropogenic Sources ◽  
Radiative Effects ◽  
Aerosol Optical Properties ◽  
Smoke Particles ◽  
Fire Source ◽  
Photolysis Rates ◽  
Meso Scale

Abstract. The present study investigates effects of wildfire emissions on air quality in Europe during an intense fire season that occurred in summer 2003. A meso-scale chemistry transport model CHIMERE is used, together with ground based and satellite aerosol optical measurements, to assess the dispersion of fire emissions and to quantify the associated radiative effects. The model has been improved to take into account the MODIS daily smoke emission inventory as well as the injection altitude of smoke particles. The simulated aerosol optical properties are inputted into a radiative transfer model to estimate (off-line) the effects of smoke particles on photolysis rates and atmospheric radiative forcing. We have found that wildfires generated comparable amounts of primary aerosol pollutants (220 kTons of PM2.5, fine particles) to anthropogenic sources during August 2003, and caused significant changes in aerosol optical properties not only close to the fire source regions, but also over a large part of Europe as a result of the long-range transport of smoke. Including these emissions into the model significantly improved its performance in simulating observed aerosol concentrations and optical properties. Quantitative comparison with MODIS and POLDER data during the major fire event (3–8 August) showed the ability of the model to reproduce high aerosol optical thickness (AOT) over Northern Europe caused by the advection of the smoke plume from the Portugal source region. Statistical analyses of model simulations showed a better agreement with observed AOT data at AERONET ground stations and suggest that wildfire emissions are responsible for a 30% enhancement in mean AOT values during the heat-wave episode. The implications for air quality over a large part of Europe are significant during this episode. First, directly, the modeled wildfire emissions caused an increase in average PM10 ground concentrations from 20 to 200%. The largest enhancement in PM10 concentrations stayed however confined within a 200 km area around the fire source locations and reached up to 40 μ g/m3. Second, indirectly, the presence of elevated smoke layers over Europe significantly altered atmospheric radiative properties: the model results imply a 10 to 30% decrease in photolysis rates and an increase in atmospheric radiative forcing of 10–35 Wm−2 during the period of strong fire influence throughout a large part of Europe. These results suggest that sporadic wildfire events may have significant effects on regional photochemistry and atmospheric stability, and need to be considered in current chemistry-transport models.

scholarly journals Characterisation of episodic aerosol types over the Australian continent

2009 ◽  
Vol 9 (6) ◽  
pp. 1943-1956 ◽  
Author(s):  
Y. Qin ◽  
R. M. Mitchell
Keyword(s):  
Cluster Analysis ◽  
Optical Properties ◽  
Radiative Forcing ◽  
Climate Models ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Back Trajectory ◽  
Enhanced Absorption ◽  
Australian Continent ◽  
Aerosol Types

Abstract. Classification of Australian continental aerosol types resulting from episodes of enhanced source activity, such as smoke plumes and dust outbreaks, is carried out via cluster analysis of optical properties obtained from inversion of sky radiance distributions at Australian aerosol ground stations using data obtained over the last decade. The cluster analysis distinguishes four significant classes, which are identified on the basis of their optical properties and provenance as determined by satellite imagery and back-trajectory analysis. The four classes are identified respectively as aged smoke, fresh smoke, coarse dust and a super-absorptive aerosol. While the first three classes show similarities with comparable aerosol types identified elsewhere, the super-absorptive aerosol has no obvious foreign prototype. The class identified as coarse dust shows a prominent depression in single scattering albedo in the blue spectral region due to absorption by hematite, which is shown to be more abundant in central Australian dust relative to the "dust belt"of the Northern Hemisphere. The super-absorptive class is distinctive in view of its very low single scattering albedo (~0.7 at 500 nm) and variable enhanced absorption at 440 nm. The strong absorption by this aerosol requires a high black carbon content while the enhanced blue-band absorption may derive from organic compounds emitted during the burning of specific vegetation types. This aerosol exerts a positive radiative forcing at the top of atmosphere (TOA), with a large deposition of energy in the atmosphere per unit aerosol optical depth. This contrasts to the other three classes where the TOA forcing is negative. Optical properties of the four types will be used to improve the representation of Australian continental aerosol in climate models, and to enhance the accuracy of satellite-based aerosol retrievals over Australia.

scholarly journals Wildfire particulate matter in Europe during summer 2003: meso-scale modeling of smoke emissions, transport and radiative effects

2007 ◽  
Vol 7 (15) ◽  
pp. 4043-4064 ◽  
Author(s):  
A. Hodzic ◽  
S. Madronich ◽  
B. Bohn ◽  
S. Massie ◽  
L. Menut ◽  
...  
Keyword(s):  
Optical Properties ◽  
Air Quality ◽  
Radiative Forcing ◽  
Anthropogenic Sources ◽  
Radiative Effects ◽  
Aerosol Optical Properties ◽  
Smoke Particles ◽  
Fire Source ◽  
Photolysis Rates ◽  
Meso Scale

Abstract. The present study investigates effects of wildfire emissions on air quality in Europe during an intense fire season that occurred in summer 2003. A meso-scale chemistry transport model CHIMERE is used, together with ground based and satellite aerosol optical measurements, to assess the dispersion of fire emissions and to quantify the associated radiative effects. The model has been improved to take into account a MODIS-derived daily smoke emission inventory as well as the injection altitude of smoke particles. The simulated aerosol optical properties are put into a radiative transfer model to estimate (off-line) the effects of smoke particles on photolysis rates and atmospheric radiative forcing. We have found that the simulated wildfires generated comparable amounts of primary aerosol pollutants (130 kTons of PM2.5, fine particles) to anthropogenic sources during August 2003, and caused significant changes in aerosol optical properties not only close to the fire source regions, but also over a large part of Europe as a result of the long-range transport of the smoke. Including these emissions into the model significantly improved its performance in simulating observed aerosol concentrations and optical properties. Quantitative comparison with MODIS and POLDER data during the major fire event (3–8 August 2003) showed the ability of the model to reproduce high aerosol optical thickness (AOT) over Northern Europe caused by the advection of the smoke plume from the Portugal source region. Although there was a fairly good spatial agreement with satellite data (correlation coefficients ranging from 0.4 to 0.9), the temporal variability of AOT data at specific AERONET locations was not well captured by the model. Statistical analyses of model-simulated AOT data at AERONET ground stations showed a significant decrease in the model biases suggesting that wildfire emissions are responsible for a 30% enhancement in mean AOT values during the heat-wave episode. The implications for air quality over a large part of Europe are significant during this episode. First, directly, the modeled wildfire emissions caused an increase in average PM2.5 ground concentrations from 20 to 200%. The largest enhancement in PM2.5 concentrations stayed, however, confined within a 200 km area around the fire source locations and reached up to 40 μg/m³. Second, indirectly, the presence of elevated smoke layers over Europe significantly altered atmospheric radiative properties: the model results imply a 10 to 30% decrease in photolysis rates and an increase in atmospheric radiative forcing of 10–35 W m−2 during the period of strong fire influence throughout a large part of Europe. These results suggest that sporadic wildfire events may have significant effects on regional photochemistry and atmospheric stability, and need to be considered in current chemistry-transport models.

scholarly journals A review of biomass burning emissions part III: intensive optical properties of biomass burning particles

2005 ◽  
Vol 5 (3) ◽  
pp. 827-849 ◽  
Author(s):  
J. S. Reid ◽  
T. F. Eck ◽  
S. A. Christopher ◽  
R. Koppmann ◽  
O. Dubovik ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Radiative Forcing ◽  
Index Of Refraction ◽  
Future Research ◽  
Smoke Particles ◽  
Particle Parameters ◽  
Direct Forcing ◽  
Biomass Burning Particles ◽  
High Degree

Abstract. Because of its wide coverage over much of the globe, biomass burning has been widely studied in the context of direct radiative forcing. Such study is warranted as smoke particles scatter and at times absorb solar radiation efficiently. Further, as much of what is known about smoke transport and impacts is based on remote sensing measurements, the optical properties of smoke particles have far reaching effects into numerous aspects of biomass burning studies. Global estimates of direct forcing have been widely varying, ranging from near zero to −1 W m-2. A significant part of this difference can be traced to varying assumptions on the optical properties of smoke. This manuscript is the third part of four examining biomass-burning emissions. Here we review and discuss the literature concerning measurement and modeling of optical properties of biomass-burning particles. These include available data from published sensitivity studies, field campaigns, and inversions from the Aerosol Robotic Network (AERONET) of Sun photometer sites. As a whole, optical properties reported in the literature are varied, reflecting both the dynamic nature of fires, variations in smoke aging processes and differences in measurement technique. We find that forward modeling or ''internal closure'' studies ultimately are of little help in resolving outstanding measurement issues due to the high degree of degeneracy in solutions when using ''reasonable'' input parameters. This is particularly notable with respect to index of refraction and the treatment of black carbon. Consequently, previous claims of column closure may in fact be more ambiguous. Differences between in situ and retrieved ωo values have implications for estimates of mass scattering and mass absorption efficiencies. In this manuscript we review and discuss this community dataset. Strengths and lapses are pointed out, future research topics are prioritized, and best estimates and uncertainties of key smoke particle parameters are provided.

scholarly journals Optical characteristics of biomass burning aerosols over Southeastern Europe determined from UV-Raman lidar measurements

2009 ◽  
Vol 9 (7) ◽  
pp. 2431-2440 ◽  
Author(s):  
V. Amiridis ◽  
D. S. Balis ◽  
E. Giannakaki ◽  
A. Stohl ◽  
S. Kazadzis ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Hot Spot ◽  
Optical Parameters ◽  
Free Troposphere ◽  
Raman Lidar ◽  
Smoke Particles ◽  
Tropospheric Aerosol ◽  
Smoke Plumes ◽  
Lidar Measurements ◽  
Uv Raman

Abstract. The influence of smoke on the aerosol loading in the free troposphere over Thessaloniki, Greece is examined in this paper. Ten cases during 2001–2005 were identified when very high aerosol optical depth values in the free troposphere were observed with a UV-Raman lidar. Particle dispersion modeling (FLEXPART) and satellite hot spot fire detection (ATSR) showed that these high free tropospheric aerosol optical depths are mainly attributed to the advection of smoke plumes from biomass burning regions over Thessaloniki. The biomass burning regions were found to extend across Russia in the latitudinal belt between 45° N–55° N, as well as in Eastern Europe (Baltic countries, Western Russia, Belarus, and the Ukraine). The highest frequency of agricultural fires occurred during the summer season (mainly in August). The data collected allowed the optical characterization of the smoke aerosols that arrived over Greece, where limited information has so far been available. Two-wavelength backscatter lidar measurements showed that the backscatter-related Ångström exponent ranged between 0.5 and 2.4 indicating a variety of particle sizes. UV-Raman lidar measurements showed that for smoke particles the extinction to backscatter ratios (so-called lidar ratios) varied between 40 sr for small particles to 100 sr for large particles. Dispersion model estimations of the carbon monoxide tracer concentration profiles for smoke particles indicate that the variability of the optical parameters is a function of the age of the smoke plumes. This information could be useful on the lidar community for reducing uncertainty in the aerosol backscatter coefficient determination due to the lidar ratio assumption, starting from a simply elastic backscatter lidar as the first satellite-borne lidar CALIPSO.

scholarly journals A review of biomass burning emissions part III: intensive optical properties of biomass burning particles

2004 ◽  
Vol 4 (5) ◽  
pp. 5201-5260 ◽  
Author(s):  
J. S. Reid ◽  
T. F. Eck ◽  
S. A. Christopher ◽  
R. Koppmann ◽  
O. Dubovik ◽  
...  
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Radiative Forcing ◽  
Index Of Refraction ◽  
Future Research ◽  
Smoke Particles ◽  
Particle Parameters ◽  
Direct Forcing ◽  
Biomass Burning Particles ◽  
High Degree

Abstract. Because of its wide coverage over much of the globe, biomass burning has been widely studied in the context of direct radiative forcing. Such study is warranted as smoke particles scatter and at times absorb solar radiation efficiently. Further, as much of what is known about smoke transport and impacts is based on remote sensing measurements, the optical properties of smoke particles have far reaching effects into numerous aspects of biomass burning studies. Global estimates of direct forcing have been widely varying, ranging from near zero to −1 Wm−2. A significant part of this difference can be traced to varying assumptions on the optical properties of smoke. This manuscript is the third part of four examining biomass-burning emissions. Here we review and discuss the literature concerning measurement and modeling of optical properties of biomass-burning particles. These include available data from published sensitivity studies, field campaigns, and inversions from the Aerosol Robotic Network (AERONET) of Sun photometer sites. As a whole, optical properties reported in the literature are varied, reflecting both the dynamic nature of fires, variations in smoke aging processes and differences in measurement technique. We find that forward modeling or "internal closure" studies ultimately are of little help in resolving outstanding measurement issues due to the high degree of degeneracy in solutions when using "reasonable" input parameters. This is particularly notable with respect to index of refraction and the treatment of black carbon. Consequently, previous claims of column closure may in fact be more ambiguous. Differences between in situ and retrieved ωo values have implications for estimates of mass scattering and mass absorption efficiencies. In this manuscript we review and discuss this community dataset. Strengths and lapses are pointed out, future research topics are prioritized, and best estimates and uncertainties of key smoke particle parameters are provided.

Optical properties of boreal forest fire smoke derived from Sun photometry

2002 ◽  
Vol 107 (D11) ◽  
pp. AAC 6-1-AAC 6-19 ◽  
Author(s):  
N. T. O'Neill ◽  
T. F. Eck ◽  
B. N. Holben ◽  
A. Smirnov ◽  
A. Royer ◽  
...  
Keyword(s):  
Optical Properties ◽  
Boreal Forest ◽  
Forest Fire ◽  
Fire Smoke
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