scholarly journals Observations of Supermicron-Sized Aerosols Originating from Biomass Burning in South Central Africa

2021 ◽  
Author(s):  
Rose Marie Miller ◽  
Greg M. McFarquhar ◽  
Robert M. Rauber ◽  
Joseph R. O'Brien ◽  
Siddhant Gupta ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Single Particle ◽  
Central Africa ◽  
Submicron Particles ◽  
Back Trajectories ◽  
Active Fire ◽  
South Central ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. During the three years of the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) campaign, the NASA Orion P-3 was equipped with a 2D-Stereo (2D-S) probe that imaged particles with maximum dimension (D) ranging from 10 < D < 1280 µm. The 2D-S recorded supermicron-sized aerosol particles (SAPs) outside of clouds within biomass burning plumes during flights over the Southeast Atlantic off Africa’s coast. Numerous SAPs with 10 < D < 1520 µm were observed in 2017 and 2018 at altitudes between 1230 m and 3500 m, 1000 km from the coastline mostly between 7–11° S. No SAPs were observed in 2016 as flights were conducted further south and further from the coastline. Number concentrations of black carbon (rBC) measured by a single particle soot photometer ranged from 200 to 1200 cm−3 when SAPs were observed. Transmission electron microscopy images of submicron particulates, collected on Holey carbon grid filters, revealed particles with potassium salts, black carbon and organics while energy-dispersive X-ray spectroscopy spectra detected potassium, a tracer for biomass burning, indicating that the submicron particles originated from biomass burning in addition to black carbon. NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) three-day back trajectories show a source in northern Angola for times when large SAPs were observed. Fire Information for Resource Management System Moderate Resolution Imaging Spectroradiometer (MODIS) 6 active fire maps showed extensive biomass burning at these locations. Given the back trajectories, the high number concentrations of rBC, and the presence of elemental tracers indicative of biomass burning, it is hypothesized that the SAPs imaged by the 2D-S are examples of unburned plant material previously seen in biomass burning smoke close to the source.

scholarly journals Observations of supermicron-sized aerosols originating from biomass burning in southern Central Africa

2021 ◽  
Vol 21 (19) ◽  
pp. 14815-14831
Author(s):  
Rose M. Miller ◽  
Greg M. McFarquhar ◽  
Robert M. Rauber ◽  
Joseph R. O'Brien ◽  
Siddhant Gupta ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Single Particle ◽  
Central Africa ◽  
Submicron Particles ◽  
Back Trajectories ◽  
Active Fire ◽  
Southern Central ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. During the 3 years of the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) campaign, the NASA Orion P-3 was equipped with a 2D stereo (2D-S) probe that imaged particles with maximum dimension (D) ranging from 10 < D < 1280 µm. The 2D-S recorded supermicron-sized aerosol particles (SAPs) outside of clouds within biomass burning plumes during flights over the southeastern Atlantic off Africa's coast. Numerous SAPs with 10 < D < 1520 µm were observed in 2017 and 2018 at altitudes between 1230 and 4000 m, 1000 km from the coastline, mostly between 7–11∘ S. No SAPs were observed in 2016 as flights were conducted further south and further from the coastline. Number concentrations of refractory black carbon (rBC) measured by a single particle soot photometer ranged from 200 to 1200 cm−3 when SAPs were observed. Transmission electron microscopy images of submicron particulates, collected on Holey carbon grid filters, revealed particles with potassium salts, black carbon (BC), and organics. Energy-dispersive X-ray spectroscopy spectra also detected potassium, a tracer for biomass burning. These measurements provided evidence that the submicron particles originated from biomass burning. NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) 3 d back trajectories show a source in northern Angola for times when large SAPs were observed. Fire Information for Resource Management System (FIRMS) Moderate Resolution Imaging Spectroradiometer (MODIS) 6 active fire maps showed extensive biomass burning at these locations. Given the back trajectories, the high number concentrations of rBC, and the presence of elemental tracers indicative of biomass burning, it is hypothesized that the SAPs imaged by the 2D-S are examples of BC aerosol, ash, or unburned plant material.

scholarly journals A new transport mechanism of biomass burning from Indochina as identified by modeling studies

2009 ◽  
Vol 9 (20) ◽  
pp. 7901-7911 ◽  
Author(s):  
C.-Y. Lin ◽  
H.-m. Hsu ◽  
Y. H. Lee ◽  
C. H. Kuo ◽  
Y.-F. Sheng ◽  
...  
Keyword(s):  
East Asia ◽  
Biomass Burning ◽  
Transport Mechanism ◽  
Dominant Role ◽  
Indochina Peninsula ◽  
Active Fire ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Simulation Results ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. Biomass burning in the Indochina Peninsula (Indochina) is one of the important ozone sources in the low troposphere over East Asia in springtime. Moderate Resolution Imaging Spectroradiometer (MODIS) data show that 20 000 or more active fire detections occurred annually in spring only from 2000 to 2007. In our tracer modeling study, we identify a new mechanism transporting the tracer over Indochina that is significantly different from the vertical transport mechanism over the equatorial areas such as Indonesia and Malaysia. Simulation results demonstrate that the leeside troughs over Indochina play a dominant role in the uplift of the tracer below 3 km, and that the strong westerlies prevailing above 3 km transport the tracer. These fundamental mechanisms have a major impact on the air quality downwind from Indochina over East Asia. The climatological importance of such a leeside trough is also discussed.

New simple approach to understand the spatial and vertical distribution of biomass burning CO emission based on the MOPITT vertical measurements

2020 ◽  
Author(s):  
Chuyong Lin ◽  
Jason Cohen
Keyword(s):  
South America ◽  
Biomass Burning ◽  
Large Scale ◽  
Central Africa ◽  
Western Africa ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Significant Spread ◽  
Spatial And Vertical Distribution

&lt;p&gt;A simple variance-maximization approach, based on 19 years of weekly Moderate Resolution Imaging spectroradiometer (MOPITT) CO vertical measurements, was employed to quantify the spatial distribution of the global seasonal biomass burning region. Results demonstrate there are a few large-scale and typical biomass burning regions responsible for most of the biomass burning emissions throughout the world, with the largest of these such regions located in Amazonian South America, Western Africa, Indonesia, and Northern Southeast Asia (Eastern India, Northern Myanmar, Laos, Vietnam and Eastern Bangladesh), which are highly associated with the results of Global Fire Emission Database(GFED). The CO is primarily lofted to and spreads downwind at 800mb or 700mb with three exceptions: The Maritime Continent and South America where there is significant spread at 300mb consistent with known deep- and pyro-convection; and Southern Africa where there is significant spread at 600mb. The total mass of CO lofted into the free troposphere ranges from 46% over Central Africa to 92% over Australia.&lt;/p&gt;

scholarly journals Biomass Burning in Africa: An Investigation of Fire Radiative Power Missed by MODIS Using the 375 m VIIRS Active Fire Product

2020 ◽  
Vol 12 (10) ◽  
pp. 1561
Author(s):  
Fangjun Li ◽  
Xiaoyang Zhang ◽  
Shobha Kondragunta
Keyword(s):  
Biomass Burning ◽  
Infrared Imaging ◽  
Fire Detection ◽  
Quantitative Information ◽  
Continental Scale ◽  
Active Fire ◽  
Radiative Power ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Fire Radiative Power

Biomass burning plays a key role in the interaction between the atmosphere and the biosphere. The nearly two-decade-old Moderate Resolution Imaging Spectroradiometer (MODIS) active fire product provides critical information (e.g., fire radiative power or FRP) for characterizing fires and estimating smoke emissions. Due to limitations of sensing geometry, MODIS fire detection capability degrades at off-nadir angles and the sensor misses the observation of fires occurring inside its equatorial swath gaps. This study investigates missing MODIS FRP observations using the 375 m Visible Infrared Imaging Radiometer Suite (VIIRS) active fire data across Africa where fire occurs in the majority of vegetation-covered areas and significantly contributes to global biomass-burning emissions. We first examine the FRP relationship between the two sensors on a continental scale and in grids of seven different resolutions. We find that MODIS misses a considerable number of low-intensity fires across Africa, which results in the underestimation of daily MODIS FRP by at least 42.8% compared to VIIRS FRP. The underestimation of MODIS FRP varies largely with grid size and satellite view angle. Based on comparisons of grid-level FRP from the two sensors, adjustment models are established at seven resolutions from 0.05°–0.5° for mitigating the underestimation of MODIS grid FRP. Furthermore, the investigation of the effect of equatorial swath gaps on MODIS FRP observations reveals that swath gaps could lead to the underestimation of MODIS monthly summed FRP by 12.5%. The quantitative information of missing MODIS FRP helps to improve our understanding of potential uncertainties in the MODIS FRP based applications, especially emissions estimation.

scholarly journals Characterising vegetative biomass burning in China using MODIS data

2014 ◽  
Vol 23 (1) ◽  
pp. 69 ◽  
Author(s):  
Xianlin Qin ◽  
Hou Yan ◽  
Zihui Zhan ◽  
Zengyuan Li
Keyword(s):  
Biomass Burning ◽  
Forest Fires ◽  
Yunnan Province ◽  
Heilongjiang Province ◽  
Active Fire ◽  
Moderate Resolution ◽  
Vegetative Biomass ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Small Forest

For Chinese fire cases, it was established that the active fire data obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) 1-km2 spatial resolution and their subsequent analysis are more accurate and spatially precise than those obtained from the statistical fire data collected by the State Forestry Administration (SFA) of P. R. China. Most (37.5%) of the biomass burning detections from 2000 to 2011 were found in croplands, followed by broadleaf forests (21.2%). Three high-density fire regions were found during the 12-year study period: (1) Heilongjiang Province, where many large forest fires occurred in April–May and September–October; (2) Yunnan Province, where many small forest fires occurred in December–May and (3) Guangdong Province and Guangxi Autonomous Regions, where most fires occurred in croplands in November–March. The largest percentage (10.72%) of the total active fire points was in Heilongjiang Province during 2000–2011, followed by Yunnan Province (10.14%), with several fires taking place in February, April and June.

scholarly journals State and evolution of the African rainforests between 1990 and 2010

2013 ◽  
Vol 368 (1625) ◽  
pp. 20120300 ◽  
Author(s):  
Philippe Mayaux ◽  
Jean-François Pekel ◽  
Baudouin Desclée ◽  
François Donnay ◽  
Andrea Lupi ◽  
...  
Keyword(s):  
West Africa ◽  
Forest Cover ◽  
Central Africa ◽  
Congo Basin ◽  
Landsat Images ◽  
Deforestation Rate ◽  
Rural And Urban ◽  
Moderate Resolution ◽  
Underlying Causes ◽  
Moderate Resolution Imaging Spectroradiometer

This paper presents a map of Africa's rainforests for 2005. Derived from moderate resolution imaging spectroradiometer data at a spatial resolution of 250 m and with an overall accuracy of 84%, this map provides new levels of spatial and thematic detail. The map is accompanied by measurements of deforestation between 1990, 2000 and 2010 for West Africa, Central Africa and Madagascar derived from a systematic sample of Landsat images—imagery from equivalent platforms is used to fill gaps in the Landsat record. Net deforestation is estimated at 0.28% yr −1 for the period 1990–2000 and 0.14% yr −1 for the period 2000–2010. West Africa and Madagascar exhibit a much higher deforestation rate than the Congo Basin, for example, three times higher for West Africa and nine times higher for Madagascar. Analysis of variance over the Congo Basin is then used to show that expanding agriculture and increasing fuelwood demands are key drivers of deforestation in the region, whereas well-controlled timber exploitation programmes have little or no direct influence on forest-cover reduction at present. Rural and urban population concentrations and fluxes are also identified as strong underlying causes of deforestation in this study.

scholarly journals Determination of enhancement ratios of HCOOH relative to CO in biomass burning plumes by the Infrared Atmospheric Sounding Interferometer (IASI)

2017 ◽  
Vol 17 (18) ◽  
pp. 11089-11105 ◽  
Author(s):  
Matthieu Pommier ◽  
Cathy Clerbaux ◽  
Pierre-Francois Coheur
Keyword(s):  
Southeast Asia ◽  
Biomass Burning ◽  
Surface Wind ◽  
Geographic Location ◽  
Surface Wind Speed ◽  
Weather Forecasts ◽  
Atmospheric Sounding ◽  
Agricultural Burning ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. Formic acid (HCOOH) concentrations are often underestimated by models, and its chemistry is highly uncertain. HCOOH is, however, among the most abundant atmospheric volatile organic compounds, and it is potentially responsible for rain acidity in remote areas. HCOOH data from the Infrared Atmospheric Sounding Interferometer (IASI) are analyzed from 2008 to 2014 to estimate enhancement ratios from biomass burning emissions over seven regions. Fire-affected HCOOH and CO total columns are defined by combining total columns from IASI, geographic location of the fires from Moderate Resolution Imaging Spectroradiometer (MODIS), and the surface wind speed field from the European Centre for Medium-Range Weather Forecasts (ECMWF). Robust correlations are found between these fire-affected HCOOH and CO total columns over the selected biomass burning regions, allowing the calculation of enhancement ratios equal to 7.30  ×  10−3 ± 0.08  ×  10−3 mol mol−1 over Amazonia (AMA), 11.10  ×  10−3 ± 1.37  ×  10−3 mol mol−1 over Australia (AUS), 6.80  ×  10−3 ± 0.44  ×  10−3 mol mol−1 over India (IND), 5.80  ×  10−3 ± 0.15  ×  10−3 mol mol−1 over Southeast Asia (SEA), 4.00  ×  10−3 ± 0.19  ×  10−3 mol mol−1 over northern Africa (NAF), 5.00  ×  10−3 ± 0.13  ×  10−3 mol mol−1 over southern Africa (SAF), and 4.40  ×  10−3 ± 0.09  ×  10−3 mol mol−1 over Siberia (SIB), in a fair agreement with previous studies. In comparison with referenced emission ratios, it is also shown that the selected agricultural burning plumes captured by IASI over India and Southeast Asia correspond to recent plumes where the chemistry or the sink does not occur. An additional classification of the enhancement ratios by type of fuel burned is also provided, showing a diverse origin of the plumes sampled by IASI, especially over Amazonia and Siberia. The variability in the enhancement ratios by biome over the different regions show that the levels of HCOOH and CO do not only depend on the fuel types.

scholarly journals Single particle characterization of biomass burning organic aerosol (BBOA): evidence for non-uniform mixing of high molecular weight organics and potassium

2015 ◽  
Vol 15 (22) ◽  
pp. 32157-32183 ◽  
Author(s):  
A. K. Y. Lee ◽  
M. D. Willis ◽  
R. M. Healy ◽  
J. M. Wang ◽  
C.-H. Jeong ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Black Carbon ◽  
High Molecular Weight ◽  
Biomass Burning ◽  
Single Particle ◽  
Critical Role ◽  
Organic Aerosol ◽  
Mixing State ◽  
Particle Measurements ◽  
Near Ultraviolet

Abstract. Biomass burning is a major source of black carbon (BC) and primary organic aerosol globally. In particular, biomass burning organic aerosol (BBOA) is strongly associated with atmospheric brown carbon (BrC) that absorbs near ultraviolet and visible light, resulting in significant impacts on regional visibility degradation and radiative forcing. The mixing state of BBOA can play a critical role in the prediction of aerosol optical properties. In this work, single particle measurements from a soot-particle aerosol mass spectrometer coupled with a light scattering module (LS-SP-AMS) were performed to examine the mixing state of BBOA, refractory black carbon (rBC) and potassium (K+, a tracer for biomass burning aerosol) in an air mass influenced by aged biomass burning. Cluster analysis of single particle measurements identified five BBOA-related particle types. rBC accounted for 3–14 w.t. % of these particle types on average. Only one particle type exhibited a strong ion signal for K+, with mass spectra characterized by low molecular weight organic species. The remaining four particle types were classified based on the apparent molecular weight of the BBOA constituents. Two particle types were associated with low potassium content and significant amounts of high molecular weight (HMW) organic compounds. Our observations indicate non-uniform mixing of particles within a biomass burning plume in terms of molecular weight and illustrate that HMW BBOA can be a key contributor to low-volatility BrC observed in BBOA particles.

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.

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