Cloud Microphysical Properties Retrieval During Intense Biomass Burning Events Over Africa and Portugal

2007 ◽  
pp. 97-111 ◽  
Author(s):  
Maria João Costa ◽  
Elsa Cattani ◽  
Vincenzo Levizzan ◽  
Ana Maria Silva
Keyword(s):  
Biomass Burning ◽  
Microphysical Properties

scholarly journals Aerosol Characterization during the Summer 2017 Huge Fire Event on Mount Vesuvius (Italy) by Remote Sensing and In Situ Observations

2021 ◽  
Vol 13 (10) ◽  
pp. 2001
Author(s):  
Antonella Boselli ◽  
Alessia Sannino ◽  
Mariagrazia D’Emilio ◽  
Xuan Wang ◽  
Salvatore Amoruso
Keyword(s):  
Remote Sensing ◽  
Biomass Burning ◽  
Ground Level ◽  
Large Area ◽  
Fire Event ◽  
Near Surface ◽  
Mean Values ◽  
Microphysical Properties ◽  
Observational Site ◽  
Biomass Burning Aerosol

During the summer of 2017, multiple huge fires occurred on Mount Vesuvius (Italy), dispersing a large quantity of ash in the surrounding area ensuing the burning of tens of hectares of Mediterranean scrub. The fires affected a very large area of the Vesuvius National Park and the smoke was driven by winds towards the city of Naples, causing daily peak values of particulate matter (PM) concentrations at ground level higher than the limit of the EU air quality directive. The smoke plume spreading over the area of Naples in this period was characterized by active (lidar) and passive (sun photometer) remote sensing as well as near-surface (optical particle counter) observational techniques. The measurements allowed us to follow both the PM variation at ground level and the vertical profile of fresh biomass burning aerosol as well as to analyze the optical and microphysical properties. The results evidenced the presence of a layer of fine mode aerosol with large mean values of optical depth (AOD > 0.25) and Ångstrom exponent (γ > 1.5) above the observational site. Moreover, the lidar ratio and aerosol linear depolarization obtained from the lidar observations were about 40 sr and 4%, respectively, consistent with the presence of biomass burning aerosol in the atmosphere.

Influence of aerosol particles from biomass burning on cloud microphysical properties and radiative forcing

2006 ◽  
Vol 82 (1-2) ◽  
pp. 310-327 ◽  
Author(s):  
E. Cattani ◽  
M.J. Costa ◽  
F. Torricella ◽  
V. Levizzani ◽  
A.M. Silva
Keyword(s):  
Biomass Burning ◽  
Radiative Forcing ◽  
Aerosol Particles ◽  
Microphysical Properties

scholarly journals Optical and microphysical properties of fresh biomass burning aerosol retrieved by Raman lidar, and star-and sun-photometry

2011 ◽  
Vol 38 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
L. Alados-Arboledas ◽  
D. Müller ◽  
J. L. Guerrero-Rascado ◽  
F. Navas-Guzmán ◽  
D. Pérez-Ramírez ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Raman Lidar ◽  
Fresh Biomass ◽  
Microphysical Properties ◽  
Biomass Burning Aerosol

scholarly journals Retrieval of aerosol microphysical and optical properties above liquid clouds from POLDER/PARASOL polarization measurements

2013 ◽  
Vol 6 (4) ◽  
pp. 991-1016 ◽  
Author(s):  
F. Waquet ◽  
C. Cornet ◽  
J.-L. Deuzé ◽  
O. Dubovik ◽  
F. Ducos ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Radiative Forcing ◽  
Mineral Dust ◽  
Spherical Particles ◽  
Dust Particles ◽  
Polarization Measurements ◽  
Microphysical Properties ◽  
Coarse Mode ◽  
Fine Mode ◽  
Aerosol Properties

Abstract. Most of the current aerosol retrievals from passive sensors are restricted to cloud-free scenes, which strongly reduces our ability to monitor the aerosol properties at a global scale and to estimate their radiative forcing. The presence of aerosol above clouds (AAC) affects the polarized light reflected by the cloud layer, as shown by the spaceborne measurements provided by the POlarization and Directionality of Earth Reflectances (POLDER) instrument on the PARASOL satellite. In a previous work, a first retrieval method was developed for AAC scenes and evaluated for biomass-burning aerosols transported over stratocumulus clouds. The method was restricted to the use of observations acquired at forward scattering angles (90–120°) where polarized measurements are highly sensitive to fine-mode particle scattering. Non-spherical particles in the coarse mode, such as mineral dust particles, do not much polarize light and cannot be handled with this method. In this paper, we present new developments that allow retrieving also the properties of mineral dust particles above clouds. These particles do not much polarize light but strongly reduce the polarized cloud bow generated by the liquid cloud layer beneath and observed for scattering angles around 140°. The spectral attenuation can be used to qualitatively identify the nature of the particles (i.e. accumulation mode versus coarse mode, i.e. mineral dust particles versus biomass-burning aerosols), whereas the magnitude of the attenuation is related to the optical thickness of the aerosol layer. We also use the polarized measurements acquired in the cloud bow to improve the retrieval of both the biomass-burning aerosol properties and the cloud microphysical properties. We provide accurate polarized radiance calculations for AAC scenes and evaluate the contribution of the POLDER polarization measurements for the simultaneous retrieval of the aerosol and cloud properties. We investigate various scenes with mineral dust particles and biomass-burning aerosols above clouds. For clouds, our results confirm that the droplet size distribution is narrow in high-latitude ocean regions and that the droplet effective radii retrieved from both polarization measurements and from total radiance measurements are generally close for AAC scenes (departures smaller than 2 μm). We found that the magnitude of the primary cloud bow cannot be accurately estimated with a plane parallel transfer radiative code. The errors for the modeling of the polarized cloud bow are between 4 and 8% for homogenous cloudy scenes, as shown by a 3-D radiative transfer code. These effects only weakly impact the retrieval of the Aerosol Optical Thickness (AOT) performed with a mineral dust particle model for which the microphysical properties are entirely known (relative error smaller than 6%). We show that the POLDER polarization measurements allow retrieving the AOT, the fine-mode particle size, the Ångström exponent and the fraction of spherical particles. However, the complex refractive index and the coarse-mode particle size cannot be accurately retrieved with the present polarization measurements. Our complete and accurate algorithm cannot be applied to process large amounts of data, so a simpler algorithm was developed to retrieve the AOT and the Ångström exponent above clouds in an operational way. Illustrations are provided for July–August 2008 near the African coast. Large mean AOTs above clouds at 0.865 μm (>0.3) are retrieved for oceanic regions near the coasts of South Africa that correspond to biomass-burning aerosols, whereas even larger mean AOTs above clouds for mineral dust particles (>0.6) are also retrieved near the coasts of Senegal. For these regions and time period, the direct AAC radiative forcing is likely to be significant. The final aim of this work is the global monitoring of the AAC properties and the estimation of the direct aerosol radiative forcing in cloudy scenes.

scholarly journals Three years of measurements of light-absorbing aerosols over coastal Namibia: seasonality, origin, and transport

2018 ◽  
Vol 18 (23) ◽  
pp. 17003-17016 ◽  
Author(s):  
Paola Formenti ◽  
Stuart John Piketh ◽  
Andreas Namwoonde ◽  
Danitza Klopper ◽  
Roelof Burger ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Marine Boundary Layer ◽  
Sampling Period ◽  
Dry Season ◽  
Back Trajectories ◽  
Microphysical Properties ◽  
Maritime Traffic ◽  
Stratocumulus Clouds ◽  
Absorbing Aerosols

Abstract. Continuous measurements between July 2012 and December 2015 at the Henties Bay Aerosol Observatory (HBAO; 22∘ S, 14∘05′ E), Namibia, show that, during the austral wintertime, transport of light-absorbing black carbon aerosols occurs at low level into the marine boundary layer. The average of daily concentrations of equivalent black carbon (eBC) over the whole sampling period is 53 (±55) ng m−3. Peak values above 200 ng m−3 and up to 800 ng m−3 occur seasonally from May to August, ahead of the dry season peak of biomass burning in southern Africa (August to October). Analysis of 3-day air mass back-trajectories show that air masses from the South Atlantic Ocean south of Henties Bay are generally cleaner than air having originated over the ocean north of Henties Bay, influenced by the outflow of the major biomass burning plume, and from the continent, where wildfires occur. Additional episodic peak concentrations, even for oceanic transport, indicate that pollution from distant sources in South Africa and maritime traffic along the Atlantic ship tracks could be important. While we expect the direct radiative effect to be negligible, the indirect effect on the microphysical properties of the stratocumulus clouds and the deposition to the ocean could be significant and deserve further investigation, specifically ahead of the dry season.

scholarly journals Vertical structure of biomass burning aerosol transported over the southeast Atlantic Ocean

2021 ◽  
Author(s):  
Harshvardhan Harshvardhan ◽  
Richard Ferrare ◽  
Sharon Burton ◽  
Johnathan Hair ◽  
Chris Hostetler ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Biomass Burning ◽  
Radiative Forcing ◽  
High Spectral Resolution ◽  
Aerosol Layer ◽  
Aerosol Extinction ◽  
Microphysical Properties ◽  
Stratocumulus Clouds ◽  
Fine Mode ◽  
Cloud Tops

Abstract. Biomass burning in southwestern Africa produces smoke plumes that are transported over the Atlantic Ocean and overlie vast regions of stratocumulus clouds. This aerosol layer contributes to direct and indirect radiative forcing of the atmosphere in this region, particularly during the months of August, September and October. There was a multi-year international campaign to study this aerosol and its interactions with clouds. Here we report on the evolution of aerosol distributions and properties as measured by the airborne high spectral resolution lidar (HSRL) during the ORACLES (Observations of Aerosols above Clouds and their intEractionS) campaign in September 2016. The NASA Langley HSRL-2 instrument was flown on the NASA ER-2 aircraft for several days in September 2016. Data were aggregated at two pairs of 2° × 2° grid boxes to examine the evolution of the vertical profile of aerosol properties during transport over the ocean. Results showed that the structure of the profile of aerosol extinction and microphysical properties is maintained over a one to two-day time scale. The fraction of aerosol in the fine mode between 50 and 500 nm remained above 0.95 and the effective radius of this fine mode was 0.16 μm from 3 to 5 km in altitude. This indicates that there is essentially no scavenging or dry deposition at these altitudes. Moreover, there is very little day to day variation in these properties, such that time sampling as happens in such campaigns, may be representative of longer periods such as monthly means. Below 3 km there is considerable mixing with larger aerosol, most likely continental source near land. Furthermore, these measurements indicated that there was a distinct gap between the bottom of the aerosol layer and cloud tops at the selected locations as evidenced by a layer of several hundred meters that contained relatively low aerosol extinction values above the clouds.

scholarly journals Sensitivity of multiangle imaging to the optical and microphysical properties of biomass burning aerosols

2008 ◽  
Vol 113 (D10) ◽  
Author(s):  
Wei-Ting Chen ◽  
Ralph A. Kahn ◽  
David Nelson ◽  
Kevin Yau ◽  
John H. Seinfeld
Keyword(s):  
Biomass Burning ◽  
Microphysical Properties ◽  
Multiangle Imaging

scholarly journals Measurements to determine the mixing state of black carbon emitted from the 2017–2018 California wildfires and urban Los Angeles

2020 ◽  
Vol 20 (24) ◽  
pp. 15635-15664
Author(s):  
Joseph Ko ◽  
Trevor Krasowsky ◽  
George Ban-Weiss
Keyword(s):  
Los Angeles ◽  
Black Carbon ◽  
Biomass Burning ◽  
Spatial Scales ◽  
Field Measurements ◽  
Mixing State ◽  
Air Masses ◽  
Microphysical Properties ◽  
Source Type ◽  
Wide Variability

Abstract. The effects of atmospheric black carbon (BC) on climate and public health have been well established, but large uncertainties remain regarding the extent of the impacts of BC at different temporal and spatial scales. These uncertainties are largely due to the heterogeneous nature of BC in terms of its spatiotemporal distribution, mixing state, and coating composition. Here, we seek to further understand the size and mixing state of BC emitted from various sources and aged over different timescales using field measurements in the Los Angeles region. We measured refractory black carbon (rBC) with a single-particle soot photometer (SP2) on Catalina Island, California (∼70 km southwest of downtown Los Angeles) during three different time periods. During the first campaign (September 2017), westerly winds were dominant and measured air masses were representative of well-aged background over the Pacific Ocean. In the second and third campaigns (December 2017 and November 2018, respectively), atypical Santa Ana wind conditions allowed us to measure biomass burning rBC (BCbb) from air masses dominated by large biomass burning events in California and fossil fuel rBC (BCff) from the Los Angeles Basin. We observed that the emissions source type heavily influenced both the size distribution of the rBC cores and the rBC mixing state. BCbb had thicker coatings and larger core diameters than BBff. We observed a mean coating thickness (CTBC) of ∼40–70 nm and a count mean diameter (CMD) of ∼120 nm for BCbb. For BCff, we observed a CTBC of ∼5–15 nm and a CMD of ∼100 nm. Our observations also provided evidence that aging led to an increased CTBC for both BCbb and BCff. Aging timescales < ∼1 d were insufficient to thickly coat freshly emitted BCff. However, CTBC for aged BCff within aged background plumes was ∼35 nm thicker than CTBC for fresh BCff. Likewise, we found that CTBC for aged BCbb was ∼18 nm thicker than CTBC for fresh BCbb. The results presented in this study highlight the wide variability in the BC mixing state and provide additional evidence that the emissions source type and aging influence rBC microphysical properties.

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