scholarly journals Biomass burning aerosol transport and vertical distribution over the South African-Atlantic region

2017 ◽  
Vol 122 (12) ◽  
pp. 6391-6415 ◽  
Author(s):  
Sampa Das ◽  
H. Harshvardhan ◽  
Huisheng Bian ◽  
Mian Chin ◽  
Gabriele Curci ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
South African ◽  
Biomass Burning ◽  
Aerosol Transport ◽  
The South ◽  
Atlantic Region ◽  
Biomass Burning Aerosol ◽  
African Atlantic

scholarly journals Variability of aerosol vertical distribution in the Sahel

2010 ◽  
Vol 10 (24) ◽  
pp. 12005-12023 ◽  
Author(s):  
O. Cavalieri ◽  
F. Cairo ◽  
F. Fierli ◽  
G. Di Donfrancesco ◽  
M. Snels ◽  
...  
Keyword(s):  
Optical Properties ◽  
West Africa ◽  
Vertical Distribution ◽  
Southern Hemisphere ◽  
Biomass Burning ◽  
Dry Season ◽  
Aerosol Transport ◽  
Air Masses ◽  
Monsoon Flow ◽  
Biomass Burning Aerosol

Abstract. In this work, we have studied the seasonal and inter-annual variability of the aerosol vertical distribution over Sahelian Africa for the years 2006, 2007 and 2008, characterizing the different kind of aerosols present in the atmosphere in terms of their optical properties observed by ground-based and satellite instruments, and their sources searched for by using trajectory analysis. This study combines data acquired by three ground-based micro lidar systems located in Banizoumbou (Niger), Cinzana (Mali) and M'Bour (Senegal) in the framework of the African Monsoon Multidisciplinary Analysis (AMMA), by the AEROsol RObotic NETwork (AERONET) sun-photometers and by the space-based Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite (Cloud-Aerosol Lidar and Infrared Pathfinder Observations). During winter, the lower levels air masses arriving in the Sahelian region come mainly from North, North-West and from the Atlantic area, while in the upper troposphere air flow generally originates from West Africa, crossing a region characterized by the presence of large biomass burning sources. The sites of Cinzana, Banizoumbou and M'Bour, along a transect of aerosol transport from East to West, are in fact under the influence of tropical biomass burning aerosol emission during the dry season, as revealed by the seasonal pattern of the aerosol optical properties, and by back-trajectory studies. Aerosol produced by biomass burning are observed mainly during the dry season and are confined in the upper layers of the atmosphere. This is particularly evident for 2006, which was characterized by a large presence of biomass burning aerosols in all the three sites. Biomass burning aerosol is also observed during spring when air masses originating from North and East Africa pass over sparse biomass burning sources, and during summer when biomass burning aerosol is transported from the southern part of the continent by the monsoon flow. During summer months, the entire Sahelian region is under the influence of Saharan dust aerosols: the air masses in low levels arrive from West Africa crossing the Sahara desert or from the Southern Hemisphere crossing the Guinea Gulf while in the upper layers air masses still originate from North, North-East. The maximum of the desert dust activity is observed in this period which is characterized by large AOD (above 0.2) and backscattering values. It also corresponds to a maximum in the extension of the aerosol vertical distribution (up to 6 km of altitude). In correspondence, a progressive cleaning up of the lowermost layers of the atmosphere is occurring, especially evident in the Banizoumbou and Cinzana sites. Summer is in fact characterized by extensive and fast convective phenomena. Lidar profiles show at times large dust events loading the atmosphere with aerosol from the ground up to 6 km of altitude. These events are characterized by large total attenuated backscattering values, and alternate with very clear profiles, sometimes separated by only a few hours, indicative of fast removal processes occurring, likely due to intense convective and rain activity. The inter-annual variability in the three year monitoring period is not very significant. An analysis of the aerosol transport pathways, aiming at detecting the main source regions, revealed that air originated from the Saharan desert is present all year long and it is observed in the lower levels of the atmosphere at the beginning and at the end of the year. In the central part of the year it extends upward and the lower levels are less affected by air masses from Saharan desert when the monsoon flow carries air from the Guinea Gulf and the Southern Hemisphere inland.

Biomass burning emissions and vertical distribution of atmospheric methyl halides and other reduced carbon gases in the South Atlantic region

1996 ◽  
Vol 101 (D19) ◽  
pp. 24151-24164 ◽  
Author(s):  
Nicola J. Blake ◽  
Donald R. Blake ◽  
Barkley C. Sive ◽  
Tai-Yih Chen ◽  
F. Sherwood Rowland ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Biomass Burning ◽  
South Atlantic ◽  
The South ◽  
Atlantic Region ◽  
Methyl Halides ◽  
South Atlantic Region ◽  
Carbon Gases

scholarly journals High-Resolution Biomass Burning Aerosol Transport Simulations in the Tropics

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 91
Author(s):  
Nurzahziani ◽  
Chinnawat Surussavadee ◽  
Thanchanok Noosook
Keyword(s):  
High Resolution ◽  
Biomass Burning ◽  
Mean Squared Error ◽  
Dry Mass ◽  
Northern Region ◽  
Emission Model ◽  
Aerosol Transport ◽  
Monthly Average ◽  
Biomass Burning Aerosol ◽  
The Tropics

This study evaluates the performance of the Weather Research and Forecasting Model with Chemistry (WRF-Chem) for simulating biomass burning aerosol transport at high resolution in the tropics using two different biomass burning emission inventories. Hourly, daily, and monthly average PM10 dry mass concentrations at 5 km resolution—simulated separately using the Brazilian Biomass Burning Emission Model (WRF-3BEM) and the Fire Inventory from NCAR (WRF-FINN) and their averages (WRF-AVG) for 3 months from February to April—are evaluated, using measurements from ground stations distributed in northern Thailand for 2014 and 2015. Results show that WRF-3BEM agrees well with observations and performs much better than WRF-FINN and WRF-AVG. WRF-3BEM simulations are almost unbiased, while those of WRF-FINN and WRF-AVG are significantly overestimated due to significant overestimates of FINN emissions. WRF-3BEM and the measured monthly average PM10 concentrations for all stations and both years are 89.22 and 87.20 μg m−3, respectively. The root mean squared error of WRF-3BEM simulated monthly average PM10 concentrations is 72.00 and 47.01% less than those of WRF-FINN and WRF-AVG, respectively. The correlation coefficient of WRF-3BEM simulated monthly PM10 concentrations and measurements is 0.89. WRF-3BEM can provide useful biomass burning aerosol transport simulations for the northern region of Thailand.

scholarly journals Biomass Burning Aerosol as a Modulator of Droplet Number in the Southeast Atlantic Region

2019 ◽  
Author(s):  
Mary Kacarab ◽  
K. Lee Thornhill ◽  
Amie Dobracki ◽  
Steven G. Howell ◽  
Joseph R. O'Brien ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Marine Boundary Layer ◽  
Cloud Condensation Nuclei ◽  
Central Africa ◽  
Aerosol Size Distribution ◽  
Atlantic Region ◽  
Radiative Impact ◽  
Biomass Burning Aerosol ◽  
Aerosol Cloud Interactions ◽  
Southeastern Atlantic

Abstract. The southeastern Atlantic (SEA) and its associated cloud deck, off the west coast of central Africa, is an area where aerosol-cloud interactions can have a strong radiative impact. Seasonally, extensive biomass burning (BB) aerosol plumes from southern Africa reach this area. The NASA ObseRvations of Aerosols above Clouds and their intEractionS (ORACLES) study focused on quantitatively understanding these interactions and their importance. Here we present measurements of cloud condensation nuclei (CCN) concentration, aerosol size distribution, and vertical updraft velocity in and around the marine boundary layer (MBL) collected by the NASA P-3B aircraft during the August 2017 ORACLES deployment. BB aerosol levels vary considerably but systematically with time; high aerosol concentrations were observed in the MBL (800–1000 cm−3) early on, decreasing mid-campaign to concentrations between 500–800 cm−3. By late August and early September, relatively clean MBL conditions were sampled (

scholarly journals The Importance of Plume Rise on the Concentrations and Atmospheric Impacts of Biomass Burning Aerosol

2016 ◽  
Author(s):  
Carolin Walter ◽  
Saulo R. Freitas ◽  
Christoph Kottmeier ◽  
Isabel Kraut ◽  
Daniel Rieger ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Biomass Burning ◽  
Forest Fires ◽  
Atmospheric Stability ◽  
Wave Radiation ◽  
Maximum Height ◽  
Plume Rise ◽  
Biomass Burning Aerosol ◽  
The Vertical Distribution ◽  
Good Agreement

Abstract. We quantified the effects of the plume rise of biomass burning aerosol and gases for the forest fires that occurred in Saskatchewan, Canada, in July 2010. For this purpose, simulations with different assumptions regarding the plume rise and the vertical distribution of the emissions were conducted. Based on comparisons with observations, applying a one-dimensional plume rise model to predict the injection layer in combination with a parametrisation of the vertical distribution of the emissions outperforms approaches in which the plume heights are initially predefined. Approximately 30 % of the fires exceed the height of 2 km and the maximum height is 8.6 km. Using this plume rise model, comparisons with satellite images in the visible spectral range show a very good agreement between the simulated and observed spatial distributions of the biomass burning plume. The simulated AOD with data of an AERONET station is in good agreement with respect to the absolute values and the timing of the maximum. Comparison of the vertical distribution of the biomass burning aerosol with CALIPSO retrievals also showed the best agreement when the plume rise model was applied. We found that down-welling surface short-wave radiation below the forest fire plume is reduced by up to 50 % and that the 2 m temperature is decreased by up to 6 K. In addition, we simulated a strong change in atmospheric stability within the biomass burning plume.

scholarly journals The effect of South American biomass burning aerosol emissions on the regional climate

2018 ◽  
Vol 18 (8) ◽  
pp. 5321-5342 ◽  
Author(s):  
Gillian D. Thornhill ◽  
Claire L. Ryder ◽  
Eleanor J. Highwood ◽  
Len C. Shaffrey ◽  
Ben T. Johnson
Keyword(s):  
Biomass Burning ◽  
Cloud Cover ◽  
Regional Climate ◽  
Shortwave Radiation ◽  
South American ◽  
The South ◽  
Clear Sky ◽  
Peak Biomass ◽  
Biomass Burning Aerosol ◽  
The Difference

Abstract. The impact of biomass burning aerosol (BBA) on the regional climate in South America is assessed using 30-year simulations with a global atmosphere-only configuration of the Met Office Unified Model. We compare two simulations of high and low emissions of biomass burning aerosol based on realistic interannual variability. The aerosol scheme in the model has hygroscopic growth and optical properties for BBA informed by recent observations, including those from the recent South American Biomass Burning Analysis (SAMBBA) intensive aircraft observations made during September 2012. We find that the difference in the September (peak biomass emissions month) BBA optical depth between a simulation with high emissions and a simulation with low emissions corresponds well to the difference in the BBA emissions between the two simulations, with a 71.6 % reduction from high to low emissions for both the BBA emissions and the BB AOD in the region with maximum emissions (defined by a box of extent 5–25∘ S, 40–70∘ W, used for calculating mean values given below). The cloud cover at all altitudes in the region of greatest BBA difference is reduced as a result of the semi-direct effect, by heating of the atmosphere by the BBA and changes in the atmospheric stability and surface fluxes. Within the BBA layer the cloud is reduced by burn-off, while the higher cloud changes appear to be responding to stability changes. The boundary layer is reduced in height and stabilized by increased BBA, resulting in reduced deep convection and reduced cloud cover at heights of 9–14 km, above the layer of BBA. Despite the decrease in cloud fraction, September downwelling clear-sky and all-sky shortwave radiation at the surface is reduced for higher emissions by 13.77 ± 0.39 W m−2 (clear-sky) and 7.37 ± 2.29 W m−2 (all-sky), whilst the upwelling shortwave radiation at the top of atmosphere is increased in clear sky by 3.32 ± 0.09 W m−2, but decreased by -1.36±1.67 W m−2 when cloud changes are included. Shortwave heating rates increase in the aerosol layer by 18 % in the high emissions case. The mean surface temperature is reduced by 0.14 ± 0.24 ∘C and mean precipitation is reduced by 14.5 % in the peak biomass region due to both changes in cloud cover and cloud microphysical properties. If the increase in BBA occurs in a particularly dry year, the resulting reduction in precipitation may exacerbate the drought. The position of the South Atlantic high pressure is slightly altered by the presence of increased BBA, and the strength of the southward low-level jet to the east of the Andes is increased. There is some evidence that some impacts of increased BBA persist through the transition into the monsoon, particularly in precipitation, but the differences are only statistically significant in some small regions in November. This study therefore provides an insight into how variability in deforestation, realized through variability in biomass burning emissions, may contribute to the South American climate, and consequently on the possible impacts of future changes in BBA emissions.

scholarly journals Supplementary material to "Biomass Burning Aerosol as a Modulator of Droplet Number in the Southeast Atlantic Region"

2019 ◽  
Author(s):  
Mary Kacarab ◽  
K. Lee Thornhill ◽  
Amie Dobracki ◽  
Steven G. Howell ◽  
Joseph R. O'Brien ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atlantic Region ◽  
Biomass Burning Aerosol ◽  
Supplementary Material
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