scholarly journals Reliability of biomass burning estimates from savanna fires: Biomass burning in northern Australia during the 1999 Biomass Burning and Lightning Experiment B field campaign

2003 ◽  
Vol 108 (D3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Jeremy Russell-Smith ◽  
Andrew C. Edwards ◽  
Garry D. Cook
Keyword(s):  
Biomass Burning ◽  
Northern Australia ◽  
Field Campaign ◽  
Savanna Fires

scholarly journals Direct measurements of the seasonality of emission factors from savanna fires in northern Australia

2012 ◽  
Vol 117 (D20) ◽  
Author(s):  
C. P. Meyer ◽  
G. D. Cook ◽  
F. Reisen ◽  
T. E. L. Smith ◽  
M. Tattaris ◽  
...  
Keyword(s):  
Emission Factors ◽  
Northern Australia ◽  
Direct Measurements ◽  
Savanna Fires

scholarly journals Radiative Heating Rate Profiles over the Southeast Atlantic Ocean during the 2016 and 2017 Biomass Burning Seasons

2020 ◽  
Author(s):  
Allison B. Marquardt Collow ◽  
Mark A. Miller ◽  
Lynne C. Trabachino ◽  
Michael P. Jensen ◽  
Meng Wang
Keyword(s):  
Atlantic Ocean ◽  
Heating Rate ◽  
Biomass Burning ◽  
Radiative Heating ◽  
Aerosol Layer ◽  
Field Campaign ◽  
Cloud Structure ◽  
Ascension Island ◽  
Biomass Burning Aerosol ◽  
Aerosol Plume

Abstract. Marine boundary layer clouds, including the transition from stratocumulus to cumulus, are poorly represented in numerical weather prediction and general circulation models. Further uncertainties in the cloud structure arise in the presence of biomass burning carbonaceous aerosol, as is the case over the southeast Atlantic Ocean where biomass burning aerosol is transported from the African continent. As the aerosol plume progresses across the southeast Atlantic Ocean, radiative heating within the aerosol layer has the potential to alter the thermodynamic environment and therefore the cloud structure; however, this has yet to be quantified. The deployment of the First Atmospheric Radiation Measurement Mobile Facility (AMF1) in support of the Layered Atlantic Smoke Interactions with Clouds (LASIC) field campaign provided a unique opportunity to collect observations of cloud and aerosol properties during two consecutive biomass burning seasons during July through October of 2016 and 2017 over Ascension Island (7.96 S, 14.35 W). Using observed profiles of temperature, humidity, and clouds from the LASIC field campaign, alongside aerosol optical properties from the Modern Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) as input for the Rapid Radiation Transfer Model (RRTM), profiles of the radiative heating rate due to aerosols and clouds were computed. Radiative heating is also assessed across the southeast Atlantic Ocean using an ensemble of back trajectories from the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT). Idealized experiments using RRTM with and without aerosols and a range of values for the single scattering albedo demonstrate that shortwave (SW) heating within the aerosol layer above Ascension Island can locally range between 2 and 8 K per day, though impacts of the aerosol can be felt elsewhere in the atmospheric column. SW radiative heating due to biomass burning aerosol is not balanced by additional longwave cooling, and the net radiative impact results in a stabilization of the lower troposphere. However, these results are extremely sensitive to the single scatter albedo and the height of the aerosol plume with respect to the inversion layer.

scholarly journals Aerosol above-cloud direct radiative effect and properties in the Namibian region during the AErosol, RadiatiOn, and CLOuds in southern Africa (AEROCLO-sA) field campaign – Multi-Viewing, Multi-Channel, Multi-Polarization (3MI) airborne simulator and sun photometer measurements

2021 ◽  
Vol 21 (10) ◽  
pp. 8233-8253
Author(s):  
Aurélien Chauvigné ◽  
Fabien Waquet ◽  
Frédérique Auriol ◽  
Luc Blarel ◽  
Cyril Delegove ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Southern Africa ◽  
Single Scattering ◽  
Visible Range ◽  
Radiative Effect ◽  
Field Campaign ◽  
Airborne Measurements ◽  
Cloud Properties ◽  
Fine Mode ◽  
Sun Photometer

Abstract. We analyse the airborne measurements of above-cloud aerosols from the AErosol, RadiatiOn, and CLOuds in southern Africa (AEROCLO-sA) field campaign performed in Namibia during August and September 2017. The study aims to retrieve the aerosol above-cloud direct radiative effect (DRE) with well-defined uncertainties. To improve the retrieval of the aerosol and cloud properties, the airborne demonstrator of the Multi-Viewing, Multi-Channel, Multi-Polarization (3MI) satellite instrument, called the Observing System Including PolaRisation in the Solar Infrared Spectrum (OSIRIS), was deployed on-board the SAFIRE (Service des Avions Français Instrumentés pour la Rechercheen Environnement) Falcon 20 aircraft during 10 flights performed over land, over the ocean, and along the Namibian coast. The airborne instrument OSIRIS provides observations at high temporal and spatial resolutions for aerosol above clouds (AACs) and cloud properties. OSIRIS was supplemented with the Photomètre Léger Aéroporté pour la surveillance des Masses d'Air version 2 (PLASMA2). The combined airborne measurements allow, for the first time, the validation of AAC algorithms previously developed for satellite measurements. The variations in the aerosol properties are consistent with the different atmospheric circulation regimes observed during the deployment. Airborne observations typically show strong aerosol optical depth (AOD; up to 1.2 at 550 nm) of fine-mode particles from biomass burning (extinction Ångström exponent varying between 1.6 and 2.2), transported above bright stratocumulus decks (mean cloud top around 1 km above mean sea level), with cloud optical thickness (COT) up to 35 at 550 nm. The above-cloud visible AOD retrieved with OSIRIS agrees within 10 % of the PLASMA2 sun photometer measurements in the same environment. The single scattering albedo (SSA) is one of the most influential parameters on the AAC DRE calculation that remains largely uncertain in models. During the AEROCLO-sA campaign, the average SSA obtained by OSIRIS at 550 nm is 0.87, which is in agreement within 3 %, on average, with previous polarimetric-based satellite and airborne retrievals. The strong absorption of the biomass burning plumes in the visible range is generally consistent with the observations from the Aerosol Robotic Network (AERONET) ground-based sun photometers. This, however, shows a significant increase in the particles' absorption at 440 nm in northern Namibia and Angola, which indicates more absorbing organic species within the observed smoke plumes. Biomass burning aerosols are also vertically collocated, with significant amounts of water content up to the top of the plume at around 6 km height in our measurements. The detailed characterization of aerosol and cloud properties, water vapour, and their uncertainties obtained from OSIRIS and PLASMA2 measurements allows us to study their impacts on the AAC DRE. The high-absorbing load of AAC, combined with high cloud albedo, leads to unprecedented DRE estimates, which are higher than previous satellite-based estimates. The average AAC DRE calculated from the airborne measurements in the visible range is +85 W m−2 (standard deviation of 26 W m−2), with instantaneous values up to +190 W m−2 during intense events. These high DRE values, associated with their uncertainties, have to be considered as new upper cases in order to evaluate the ability of models to reproduce the radiative impact of the aerosols over the southeastern Atlantic region.

scholarly journals Long-term multi-source data analysis about the characteristics of aerosol optical properties and types over Australia

2021 ◽  
Vol 21 (5) ◽  
pp. 3803-3825
Author(s):  
Xingchuan Yang ◽  
Chuanfeng Zhao ◽  
Yikun Yang ◽  
Hao Fan
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Seasonal Variations ◽  
Northern Australia ◽  
Aerosol Optical Properties ◽  
Austral Spring ◽  
Australian Continent ◽  
Modis Aod ◽  
Central Australia ◽  
Aerosol Types

Abstract. The spatiotemporal distributions of aerosol optical properties and major aerosol types, along with the vertical distribution of major aerosol types over Australia, are investigated based on multi-year Aerosol Robotic Network (AERONET) observations at nine sites, the Moderate Resolution Imaging Spectroradiometer (MODIS), Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and back-trajectory analysis from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT). During the observation period from 2001–2020, the annual aerosol optical depth (AOD) at most sites showed increasing trends (0.002–0.029 yr−1), except for that at three sites, Canberra, Jabiru, and Lake Argyle, which showed decreasing trends (−0.004 to −0.014 yr−1). In contrast, the annual Ångström exponent (AE) showed decreasing tendencies at most sites (−0.045 to −0.005 yr−1). The results showed strong seasonal variations in AOD, with high values in the austral spring and summer and relatively low values in the austral fall and winter, and weak seasonal variations in AE, with the highest mean values in the austral spring at most sites. Monthly average AOD increases from August to December or the following January and decreases during March–July. Spatially, the MODIS AOD showed obvious spatial heterogeneity, with high values appearing over the Australian tropical savanna regions, Lake Eyre Basin, and southeastern regions of Australia, while low values appeared over the arid regions in western Australia. MERRA-2 showed that carbonaceous aerosol over northern Australia, dust over central Australia, sulfate over densely populated northwestern and southeastern Australia, and sea salt over Australian coastal regions are the major types of atmospheric aerosols. The nine ground-based AERONET sites over Australia showed that the mixed type of aerosols (biomass burning and dust) is dominant in all seasons. Moreover, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) showed that polluted dust is the dominant aerosol type detected at heights 0.5–5 km over the Australian continent during all seasons. The results suggested that Australian aerosol has similar source characteristics due to the regional transport over Australia, especially for biomass burning and dust aerosols. However, the dust-prone characteristic of aerosol is more prominent over central Australia, while the biomass-burning-prone characteristic of aerosol is more prominent in northern Australia.

scholarly journals Dry season aerosol iron solubility in tropical northern Australia

2016 ◽  
Vol 16 (19) ◽  
pp. 12829-12848 ◽  
Author(s):  
V. Holly L. Winton ◽  
Ross Edwards ◽  
Andrew R. Bowie ◽  
Melita Keywood ◽  
Alistair G. Williams ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Biomass Burning ◽  
Algal Blooms ◽  
Atmospheric Transport ◽  
Dry Season ◽  
Global Ocean ◽  
Future Research ◽  
Northern Australia ◽  
Tropical Waters ◽  
The Tropics

Abstract. Marine nitrogen fixation is co-limited by the supply of iron (Fe) and phosphorus in large regions of the global ocean. The deposition of soluble aerosol Fe can initiate nitrogen fixation and trigger toxic algal blooms in nitrate-poor tropical waters. We present dry season soluble Fe data from the Savannah Fires in the Early Dry Season (SAFIRED) campaign in northern Australia that reflects coincident dust and biomass burning sources of soluble aerosol Fe. The mean soluble and total aerosol Fe concentrations were 40 and 500 ng m−3 respectively. Our results show that while biomass burning species may not be a direct source of soluble Fe, biomass burning may substantially enhance the solubility of mineral dust. We observed fractional Fe solubility up to 12 % in mixed aerosols. Thus, Fe in dust may be more soluble in the tropics compared to higher latitudes due to higher concentrations of biomass-burning-derived reactive organic species in the atmosphere. In addition, biomass-burning-derived particles can act as a surface for aerosol Fe to bind during atmospheric transport and subsequently be released to the ocean upon deposition. As the aerosol loading is dominated by biomass burning emissions over the tropical waters in the dry season, additions of biomass-burning-derived soluble Fe could have harmful consequences for initiating nitrogen-fixing toxic algal blooms. Future research is required to quantify biomass-burning-derived particle sources of soluble Fe over tropical waters.

scholarly journals Long-term multi-source data analysis about the characteristics of aerosol optical properties and types over Australia

2020 ◽  
Author(s):  
Xingchuan Yang ◽  
Chuanfeng Zhao ◽  
Yikun Yang
Keyword(s):  
Optical Properties ◽  
Biomass Burning ◽  
Seasonal Variations ◽  
Dust Aerosol ◽  
Northern Australia ◽  
Aerosol Optical Properties ◽  
Austral Spring ◽  
Modis Aod ◽  
Central Australia ◽  
Aerosol Types

Abstract. The spatiotemporal distributions of aerosol optical properties and major aerosol types, along with the vertical distribution of major aerosol types over Australia, are investigated based on multi-year AERONET observations at nine sites, the Moderate Resolution Imaging Spectroradiometer (MODIS), Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and back-trajectory analysis from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT). The annual aerosol optical depth (AOD) at most sites showed increasing trends (0.002–0.028 yr−1) except for that at three sites of Canberra, Jabiru, and Lake Argyle, which showed decreasing trends (−0.004–−0.002 yr−1). In contrast, the annual Ångström exponent (AE) showed decreasing tendencies at most sites (−0.044–−0.005 yr−1). The results showed strong seasonal variations in AOD with high values in the austral spring and summer and relatively low values in the austral fall and winter, and weak seasonal variations in AE with the highest mean values in the austral spring at most sites. Spatially, the MODIS AOD showed obvious spatial heterogeneity with higher values appeared over the Australian tropical savanna regions, Lake Eyre Basin, and southeastern regions of Australia, while low values appeared over the arid regions in western Australia. Monthly averaged AOD increases from August to next austral spring peak (typically December–January), and decreases during the March–July. Classification of Australian aerosols revealed that the mixed type of aerosols (biomass burning and dust aerosol) are dominated in all seasons at nine sites, followed by biomass burning aerosol and dust aerosol. The MERRA-2 showed that carbonaceous over northern Australia, dust over central Australia, sulfate over densely populated northwestern and southeastern Australia, and sea salt over Australian coastal regions are the major types of atmospheric aerosols over Australia. The CALIPSO showed that polluted dust is the dominant aerosol type detected at heights 0.5–5 km during all seasons. Australian aerosol has similar source characteristics due to intercontinental transport of aerosols over Australia, especially for biomass burning and dust aerosols. However, the dust-prone characteristic of aerosol is more prominent over the central Australia, while the biomass burning-prone characteristic of aerosol is more prominent in northern Australia.

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