scholarly journals Biomass-burning smoke heights over the Amazon observed from space

2019 ◽  
Vol 19 (3) ◽  
pp. 1685-1702 ◽  
Author(s):  
Laura Gonzalez-Alonso ◽  
Maria Val Martin ◽  
Ralph A. Kahn
Keyword(s):  
Vertical Distribution ◽  
Tropical Forest ◽  
Biomass Burning ◽  
Forest Fires ◽  
Atmospheric Stability ◽  
Free Troposphere ◽  
Smoke Plume ◽  
Smoke Plumes ◽  
Drought Conditions ◽  
The Vertical Distribution

Abstract. We characterise the vertical distribution of biomass-burning emissions across the Amazon during the biomass-burning season (July–November) with an extensive climatology of smoke plumes derived from MISR and MODIS (2005–2012) and CALIOP (2006–2012) observations. Smoke plume heights exhibit substantial variability, spanning a few hundred metres up to 6 km above the terrain. However, the majority of the smoke is located at altitudes below 2.5 km. About 60 % of smoke plumes are observed in drought years, 40 %–50 % at the peak month of the burning season (September) and 94 % over tropical forest and savanna regions, with respect to the total number of smoke plume observations. At the time of the MISR observations (10:00–11:00 LT), the highest plumes are detected over grassland fires (with an averaged maximum plume height of ∼1100 m) and the lowest plumes occur over tropical forest fires (∼800 m). A similar pattern is found later in the day (14:00–15:00 LT) with CALIOP, although at higher altitudes (2300 m grassland vs. 2000 m tropical forest), as CALIOP typically detects smoke at higher altitudes due to its later overpass time, associated with a deeper planetary boundary layer, possibly more energetic fires, and greater sensitivity to thin aerosol layers. On average, 3 %–20 % of the fires inject smoke into the free troposphere; this percentage tends to increase toward the end of the burning season (November: 15 %–40 %). We find a well-defined seasonal cycle between MISR plume heights, MODIS fire radiative power and atmospheric stability across the main biomes of the Amazon, with higher smoke plumes, more intense fires and reduced atmospheric stability conditions toward the end of the burning season. Lower smoke plume heights are detected during drought (800 m) compared to non-drought (1100 m) conditions, in particular over tropical forest and savanna fires. Drought conditions favour understory fires over tropical forest, which tend to produce smouldering combustion and low smoke injection heights. Droughts also seem to favour deeper boundary layers and the percentage of smoke plumes that reach the free troposphere is lower during these dry conditions. Consistent with previous studies, the MISR mid-visible aerosol optical depth demonstrates that smoke makes a significant contribution to the total aerosol loading over the Amazon, which in combination with lower injection heights in drought periods has important implications for air quality. This work highlights the importance of biome type, fire properties and atmospheric and drought conditions for plume dynamics and smoke loading. In addition, our study demonstrates the value of combining observations of MISR and CALIOP constraints on the vertical distribution of smoke from biomass burning over the Amazon.

scholarly journals Biomass burning smoke heights over the Amazon observed from space

2018 ◽  
Author(s):  
Laura Gonzalez-Alonso ◽  
Maria Val Martin ◽  
Ralph A. Kahn
Keyword(s):  
Vertical Distribution ◽  
Tropical Forest ◽  
Biomass Burning ◽  
Forest Fires ◽  
Atmospheric Stability ◽  
Atmospheric Conditions ◽  
Smoke Plume ◽  
Smoke Plumes ◽  
Drought Conditions ◽  
The Vertical Distribution

Abstract. We characterize the vertical distribution of biomass burning emissions across the Amazon during the biomass burning season with an extensive climatology of smoke plumes derived from MISR and MODIS (2005–2012) and CALIOP (2006–2012) observations. Smoke plume heights exhibit substantial variability, spanning a few hundred meters up to 6 km above the terrain. However, the majority of the smoke is located at altitudes below 2.5 km. About 60 % of smoke plumes are observed during drought years, at the peak month of the burning season (September; 40–50 %) and over tropical forest and savanna regions (94 %). At the time of the MISR observations (10:00–11:00 LT), the highest plumes are detected over grassland fires (1100 m maximum plume height average) and the lowest plumes occur over tropical forest fires (~ 800 m). A similar pattern is found later in the day (14:00–15:00 LT) with CALIOP, although at higher altitudes (2300 m grassland versus 2000 m tropical forest), as CALIOP typically detects smoke at higher altitudes due to its greater sensitivity to thin aerosol layers. On average, 3–20 % of the fires inject smoke into the free troposphere; this percentage can increase toward the end of the burning season (November; 15–40 %). We find a well-defined seasonal cycle between MISR plume heights, MODIS Fire Radiative Power (FRP) and atmospheric stability across the main biomes of the Amazon, with higher smoke plumes, more intense fires and reduced atmospheric stability conditions toward the end of the burning season. Lower smoke plume heights are detected during drought (800 m) compared to non-drought (1100 m) conditions, in particular over tropical forest and savanna fires. Drought conditions favour understory fires over tropical forest, which tend to produce smouldering combustion and low smoke injection heights. Droughts also seem to favour deeper boundary layers and the percentage of smoke plumes that reach the FT is lower during these dry conditions. Consistent with previous studies, the MISR mid-visible aerosol optical depth demonstrates that smoke makes a significant contribution to the total aerosol loading over the Amazon, with important implications for air quality. This work highlights the importance of biome type, fire properties and atmospheric conditions for plume dynamics, as well as the effect of drought conditions on smoke loading. In addition, our study demonstrates that combined observations of MISR and CALIOP allows for better constraints on the vertical distribution of smoke from biomass burning over the Amazon.

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 importance of plume rise on the concentrations and atmospheric impacts of biomass burning aerosol

2016 ◽  
Vol 16 (14) ◽  
pp. 9201-9219 ◽  
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 parametrization 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 with a maximum height of 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 aerosol optical depth (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 (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) retrievals also showed the best agreement when the plume rise model was applied. We found that downwelling 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 vertical distribution of biomass burning pollution over tropical South America from aircraft in situ measurements during SAMBBA

2019 ◽  
Vol 19 (9) ◽  
pp. 5771-5790 ◽  
Author(s):  
Eoghan Darbyshire ◽  
William T. Morgan ◽  
James D. Allan ◽  
Dantong Liu ◽  
Michael J. Flynn ◽  
...  
Keyword(s):  
Air Quality ◽  
South America ◽  
Vertical Distribution ◽  
Biomass Burning ◽  
Mixing Layer ◽  
Free Troposphere ◽  
The West ◽  
The Vertical Distribution ◽  
Tropical South America

Abstract. We examine processes driving the vertical distribution of biomass burning pollution following an integrated analysis of over 200 pollutant and meteorological profiles measured in situ during the South AMerican Biomass Burning Analysis (SAMBBA) field experiment. This study will aid future work examining the impact of biomass burning on weather, climate and air quality. During the dry season there were significant contrasts in the composition and vertical distribution of haze between western and eastern regions of tropical South America. Owing to an active or residual convective mixing layer, the aerosol abundance was similar from the surface to ∼1.5 km in the west and ∼3 km in the east. Black carbon mass loadings were double as much in the east (1.7 µg m−3) than the west (0.85 µg m−3), but aerosol scattering coefficients at 550 nm were similar (∼120 Mm−1), as too were CO near-surface concentrations (310–340 ppb). We attribute these contrasts to the more flaming combustion of Cerrado fires in the east and more smouldering combustion of deforestation and pasture fires in the west. Horizontal wind shear was important in inhibiting mixed layer growth and plume rise, in addition to advecting pollutants from the Cerrado regions into the remote tropical forest of central Amazonia. Thin layers above the mixing layer indicate the roles of both plume injection and shallow moist convection in delivering pollution to the lower free troposphere. However, detrainment of large smoke plumes into the upper free troposphere was very infrequently observed. Our results reiterate that thermodynamics control the pollutant vertical distribution and thus point to the need for correct model representation so that the spatial distribution and vertical structure of biomass burning smoke is captured. We observed an increase of aerosol abundance relative to CO with altitude both in the background haze and plume enhancement ratios. It is unlikely associated with thermodynamic partitioning, aerosol deposition or local non-fire sources. We speculate it may be linked to long-range transport from West Africa or fire combustion efficiency coupled to plume injection height. Further enquiry is required to explain the phenomenon and explore impacts on regional climate and air quality.

scholarly journals The vertical distribution of biomass burning pollution over tropical South America from aircraft in situ measurements during SAMBBA

2018 ◽  
Author(s):  
Eoghan Darbyshire ◽  
William T. Morgan ◽  
James D. Allan ◽  
Dantong Liu ◽  
Michael J. Flynn ◽  
...  
Keyword(s):  
South America ◽  
Vertical Distribution ◽  
Biomass Burning ◽  
Mixing Layer ◽  
Thin Layers ◽  
Horizontal Wind ◽  
Free Troposphere ◽  
The West ◽  
The Vertical Distribution ◽  
Tropical South America

Abstract. To reduce the uncertainties in processes driving the vertical distribution of biomass burning pollutants, and thus impacts on regional weather and climate, we present an integrated analysis of vertical profiles of pollutants and meteorological parameters measured on flights during the 2012 South American Biomass Burning Analysis (SAMBBA) field experiment. During the dry season there were significant contrasts in the composition and vertical distribution of haze between western and eastern regions of tropical South America. Owing to an active or residual convective mixing layer, the aerosol burden was similar from the surface to ~ 1.5 km in the west and ~ 3 km in the east. Black carbon mass loadings were double in the east (1.7 µg cm−3) than west (0.85 µg cm−3) but aerosol scattering coefficients at 550 nm were similar (~ 120 Mm−1), as too were CO surface concentrations (310–340 ppb). We attribute these contrasts to the more flaming combustion of Cerrado fires in the east and more smouldering combustion of deforestation and pasture fires in the west. Horizontal wind shear was important in inhibiting mixed layer growth and plume rise, in addition to advecting pollutants from the Cerrado regions into the remote tropical forest of central Amazonia. Optically thin layers above the mixing layer indicates roles for both plume injection and shallow moist convection in delivering pollution to the lower free troposphere. However, detrainment of large smoke plumes into the upper free troposphere was very infrequently observed. Our results reiterate that thermodynamics control the pollutant vertical distribution and thus point to the need for correct model representation so the spatial distribution and vertical structure of biomass burning smoke is captured. Our observations of relatively large concentrations of aerosol aloft and of CO near surface suggest that there is a greater contribution of pollutants from more complete combustion with altitude. Release of appropriate emissions from the initial more flaming and later residual smouldering phases of a fire at appropriate altitudes may be especially important to ensure models can accurately predict aerosol-radiation, aerosol-cloud and air quality impacts.

Black Carbon profiles from tethered balloon flights over the Southeastern Tibetan Plateau

2020 ◽  
Author(s):  
Mo Wang ◽  
Baiqing Xu ◽  
Song Yang ◽  
Jing Gao ◽  
Taihua Zhang ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Relative Humidity ◽  
Tibetan Plateau ◽  
Vertical Distribution ◽  
Biomass Burning ◽  
Vertical Profile ◽  
Mass Concentration ◽  
Maximum Height ◽  
Free Troposphere ◽  
Tethered Balloon

<p>Black carbon (BC) can change the energy budget of the earth system by strongly absorbing solar radiation: both suspended in the atmosphere, incorporated into cloud droplets, or deposited onto high-albedo surfaces. BC’s direct radiative forcing is highly dependent on its vertical distribution. However, due to large variabilities and the small number of vertical profile measurements, there is still large uncertainty in this forcing value. Moreover, the vertical profile of BC and its relative elevation to clouds determine BC’s lifetime in the atmosphere and its transport and removal processes. In November-December 2017, a series of tethered balloon flights was launched at the Southeast Tibet Observation and Research Station for the Alpine Environment of the Chinese Academy of Sciences. A cylindrical balloon with a diameter of 7.9 m and maximum volume of 1250 m<sup>3</sup> was used. A 7-channel Aethalometer was installed in the gondola attached to the balloon, together with several other instruments including a GPS for altitude, and sensors for temperature and relative humidity. The airborne Aethalometer measured BC mass concentration (ng/m<sup>3</sup>) on a on a 1-second timebase at 7 wavelengths ranging from 370 nm to 950 nm. Meanwhile, another Aethalometer was used to monitor BC mass concentration near the surface, at a height of about 10 m above the ground. From the tethered balloon flights, we derived three profiles designated as ‘F1’, ‘F3-ASC’, and ‘F3-DES’. The maximum height for the F1 flight was 500 m a.g.l., namely 3800 m a.s.l.; while the maximum height for the F3 flight was 1950 m a.g.l., namely 5250 m a.s.l. Based on the potential temperature and relative humidity data, the profiles were divided into three layers: the stable boundary layer (SBL), the residual layer (RL), and the free troposphere (FT). The vertical distribution of BC shows a prominent peak within the SBL. The mean BC concentration in SBL (1000±750 ng/m<sup>3</sup>) was one order of magnitude higher than in RL and FT, which were 140±40 ng/m<sup>3</sup> and 120±40 ng/m<sup>3</sup>, respectively. The BC concentration measured in the present study in FT over the southeastern Tibetan Plateau is comparable to measurements in Arctic regions, but lower than values in South Asia. Analysis of the wavelength dependence of the data yields an estimate of the biomass burning contribution. This showed a maximum value in SBL of 44±37%, and was 16±6% in RL and 13±5% in FT. Analysis of 24-hour isentropic back trajectories showed that BC in SBL and RL was dominated by local sources, while in the FT, BC is mainly influenced by mid- to long-distant transport by the westerlies. In addition, analysis of the variations of BC concentration and biomass burning contribution on a high-resolution time scale showed that BC concentrations and the nature of their sources are largely influenced by air mass origins and transport. To our knowledge, this is the first ever in situ measurement of BC concentration over the Tibetan Plateau in the atmospheric boundary layer and free troposphere up to 5000 m a.s.l.</p>

scholarly journals Development and optimization of a wildfire plume rise model based on remote sensing data inputs – Part 2

2015 ◽  
Vol 15 (6) ◽  
pp. 9815-9895 ◽  
Author(s):  
R. Paugam ◽  
M. Wooster ◽  
J. Atherton ◽  
S. R. Freitas ◽  
M. G. Schultz ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Atmospheric Stability ◽  
Quality Criteria ◽  
Landscape Scale ◽  
Training Dataset ◽  
Plume Rise ◽  
Plume Height ◽  
Smoke Plume ◽  
The Impact

Abstract. Biomass burning is one of a relatively few natural processes that can inject globally significant quantities of gases and aerosols into the atmosphere at altitudes well above the planetary boundary layer, in some cases at heights in excess of 10 km. The "injection height" of biomass burning emissions is therefore an important parameter to understand when considering the characteristics of the smoke plumes emanating from landscape scale fires, and in particular when attempting to model their atmospheric transport. Here we further extend the formulations used within a popular 1D plume rise model, widely used for the estimation of landscape scale fire smoke plume injection height, and develop and optimise the model both so that it can run with an increased set of remotely sensed observations. The model is well suited for application in atmospheric Chemistry Transport Models (CTMs) aimed at understanding smoke plume downstream impacts, and whilst a number of wildfire emission inventories are available for use in such CTMs, few include information on plume injection height. Since CTM resolutions are typically too spatially coarse to capture the vertical transport induced by the heat released from landscape scale fires, approaches to estimate the emissions injection height are typically based on parametrizations. Our extensions of the existing 1D plume rise model takes into account the impact of atmospheric stability and latent heat on the plume up-draft, driving it with new information on active fire area and fire radiative power (FRP) retrieved from MODIS satellite Earth Observation (EO) data, alongside ECMWF atmospheric profile information. We extend the model by adding an equation for mass conservation and a new entrainment scheme, and optimise the values of the newly added parameters based on comparison to injection heights derived from smoke plume height retrievals made using the MISR EO sensor. Our parameter optimisation procedure is based on a twofold approach using sequentially a Simulating Annealing algorithm and a Markov chain Monte Carlo uncertainty test, and to try to ensure the appropriate convergence on suitable parameter values we use a training dataset consisting of only fires where a number of specific quality criteria are met, including local ambient wind shear limits derived from the ECMWF and MISR data, and "steady state" plumes and fires showing only relatively small changes between consecutive MODIS observations. Using our optimised plume rise model (PRMv2) with information from all MODIS-detected active fires detected in 2003 over North America, with outputs gridded to a 0.1° horizontal and 500 m vertical resolution mesh, we are able to derive wildfire injection height distributions whose maxima extend to the type of higher altitudes seen in actual observation-based wildfire plume datasets than are those derived either via the original plume model or any other parametrization tested herein. We also find our model to be the only one tested that more correctly simulates the very high plume (6 to 8 km a.s.l.), created by a large fire in Alberta (Canada) on the 17 August 2003, though even our approach does not reach the stratosphere as the real plume is expected to have done. Our results lead us to believe that our PRMv2 approach to modelling the injection height of wildfire plumes is a strong candidate for inclusion into CTMs aiming to represent this process, but we note that significant advances in the spatio-temporal resolutions of the data required to feed the model will also very likely bring key improvements in our ability to more accurately represent such phenomena, and that there remain challenges to the detailed validation of such simulations due to the relative sparseness of plume height observations and their currently rather limited temporal coverage which are not necessarily well matched to when fires are most active (MISR being confined to morning observations for example).

scholarly journals Boreal forest fire emissions in fresh Canadian smoke plumes: C<sub>1</sub>-C<sub>10</sub> volatile organic compounds (VOCs), CO<sub>2</sub>, CO, NO<sub>2</sub>, NO, HCN and CH<sub>3</sub>CN

2011 ◽  
Vol 11 (13) ◽  
pp. 6445-6463 ◽  
Author(s):  
I. J. Simpson ◽  
S. K. Akagi ◽  
B. Barletta ◽  
N. J. Blake ◽  
Y. Choi ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Organic Compounds ◽  
Biomass Burning ◽  
Forest Fires ◽  
Trace Gas ◽  
Air Samples ◽  
Fire Emissions ◽  
Trace Gas Emissions ◽  
Smoke Plumes ◽  
Volatile Organic

Abstract. Boreal regions comprise about 17 % of the global land area, and they both affect and are influenced by climate change. To better understand boreal forest fire emissions and plume evolution, 947 whole air samples were collected aboard the NASA DC-8 research aircraft in summer 2008 as part of the ARCTAS-B field mission, and analyzed for 79 non-methane volatile organic compounds (NMVOCs) using gas chromatography. Together with simultaneous measurements of CO2, CO, CH4, CH2O, NO2, NO, HCN and CH3CN, these measurements represent the most comprehensive assessment of trace gas emissions from boreal forest fires to date. Based on 105 air samples collected in fresh Canadian smoke plumes, 57 of the 80 measured NMVOCs (including CH2O) were emitted from the fires, including 45 species that were quantified from boreal forest fires for the first time. After CO2, CO and CH4, the largest emission factors (EFs) for individual species were formaldehyde (2.1 ± 0.2 g kg−1), followed by methanol, NO2, HCN, ethene, α-pinene, β-pinene, ethane, benzene, propene, acetone and CH3CN. Globally, we estimate that boreal forest fires release 2.4 ± 0.6 Tg C yr−1 in the form of NMVOCs, with approximately 41 % of the carbon released as C1-C2 NMVOCs and 21 % as pinenes. These are the first reported field measurements of monoterpene emissions from boreal forest fires, and we speculate that the pinenes, which are relatively heavy molecules, were detected in the fire plumes as the result of distillation of stored terpenes as the vegetation is heated. Their inclusion in smoke chemistry models is expected to improve model predictions of secondary organic aerosol (SOA) formation. The fire-averaged EF of dichloromethane or CH2Cl2, (6.9 ± 8.6) × 10−4 g kg−1, was not significantly different from zero and supports recent findings that its global biomass burning source appears to have been overestimated. Similarly, we found no evidence for emissions of chloroform (CHCl3) or methyl chloroform (CH3CCl3) from boreal forest fires. The speciated hydrocarbon measurements presented here show the importance of carbon released by short-chain NMVOCs, the strong contribution of pinene emissions from boreal forest fires, and the wide range of compound classes in the most abundantly emitted NMVOCs, all of which can be used to improve biomass burning inventories in local/global models and reduce uncertainties in model estimates of trace gas emissions and their impact on the atmosphere.

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