A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source
As a representative site of the southern African biomass-burning region, sun-sky data from the 15 year Aerosol Robotic Network (AERONET) deployment at Mongu, Zambia, was analyzed. For the biomass-burning season months (July-November), we investigate seasonal trends in aerosol single scattering albed...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20140016775 2023-05-15T13:06:46+02:00 A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source Piketh, S. J. Hyer, E. J. Holben, B. N. Jethva, H. T. Torres, O. Sorokin, M. Sinyuk, A. Reid, J. S. Ward, D. E. Giles, D. M. Dubovik, O. Eck, T. F. Slutsker, I. Mukelabai, M. M. Smirnov, A. Schafer, J. S. Unclassified, Unlimited, Publicly available June 19, 2013 application/pdf http://hdl.handle.net/2060/20140016775 unknown Document ID: 20140016775 http://hdl.handle.net/2060/20140016775 Copyright, Distribution as joint owner in the copyright CASI Earth Resources and Remote Sensing GSFC-E-DAA-TN14590 Journal of Geophysical Research: Atmospheres; 118; 12; 6414-6432 2013 ftnasantrs 2019-07-21T00:22:21Z As a representative site of the southern African biomass-burning region, sun-sky data from the 15 year Aerosol Robotic Network (AERONET) deployment at Mongu, Zambia, was analyzed. For the biomass-burning season months (July-November), we investigate seasonal trends in aerosol single scattering albedo (SSA), aerosol size distributions, and refractive indices from almucantar sky scan retrievals. The monthly mean single scattering albedo at 440 nm in Mongu was found to increase significantly from approx. 0.84 in July to approx. 0.93 in November (from 0.78 to 0.90 at 675 nm in these same months). There was no significant change in particle size, in either the dominant accumulation or secondary coarse modes during these months, nor any significant trend in the Angstrom exponent (440-870 nm; r(exp 2) = 0.02). A significant downward seasonal trend in imaginary refractive index (r(exp 2) = 0.43) suggests a trend of decreasing black carbon content in the aerosol composition as the burning season progresses. Similarly, burning season SSA retrievals for the Etosha Pan, Namibia AERONET site also show very similar increasing single scattering albedo values and decreasing imaginary refractive index as the season progresses. Furthermore, retrievals of SSA at 388 nm from the Ozone Monitoring Instrument satellite sensor show similar seasonal trends as observed by AERONET and suggest that this seasonal shift is widespread throughout much of southern Africa. A seasonal shift in the satellite retrieval bias of aerosol optical depth from the Moderate Resolution Imaging Spectroradiometer collection 5 dark target algorithm is consistent with this seasonal SSA trend since the algorithm assumes a constant value of SSA. Multi-angle Imaging Spectroradiometer, however, appears less sensitive to the absorption-induced bias. Other/Unknown Material Aerosol Robotic Network NASA Technical Reports Server (NTRS) |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Earth Resources and Remote Sensing |
spellingShingle |
Earth Resources and Remote Sensing Piketh, S. J. Hyer, E. J. Holben, B. N. Jethva, H. T. Torres, O. Sorokin, M. Sinyuk, A. Reid, J. S. Ward, D. E. Giles, D. M. Dubovik, O. Eck, T. F. Slutsker, I. Mukelabai, M. M. Smirnov, A. Schafer, J. S. A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source |
topic_facet |
Earth Resources and Remote Sensing |
description |
As a representative site of the southern African biomass-burning region, sun-sky data from the 15 year Aerosol Robotic Network (AERONET) deployment at Mongu, Zambia, was analyzed. For the biomass-burning season months (July-November), we investigate seasonal trends in aerosol single scattering albedo (SSA), aerosol size distributions, and refractive indices from almucantar sky scan retrievals. The monthly mean single scattering albedo at 440 nm in Mongu was found to increase significantly from approx. 0.84 in July to approx. 0.93 in November (from 0.78 to 0.90 at 675 nm in these same months). There was no significant change in particle size, in either the dominant accumulation or secondary coarse modes during these months, nor any significant trend in the Angstrom exponent (440-870 nm; r(exp 2) = 0.02). A significant downward seasonal trend in imaginary refractive index (r(exp 2) = 0.43) suggests a trend of decreasing black carbon content in the aerosol composition as the burning season progresses. Similarly, burning season SSA retrievals for the Etosha Pan, Namibia AERONET site also show very similar increasing single scattering albedo values and decreasing imaginary refractive index as the season progresses. Furthermore, retrievals of SSA at 388 nm from the Ozone Monitoring Instrument satellite sensor show similar seasonal trends as observed by AERONET and suggest that this seasonal shift is widespread throughout much of southern Africa. A seasonal shift in the satellite retrieval bias of aerosol optical depth from the Moderate Resolution Imaging Spectroradiometer collection 5 dark target algorithm is consistent with this seasonal SSA trend since the algorithm assumes a constant value of SSA. Multi-angle Imaging Spectroradiometer, however, appears less sensitive to the absorption-induced bias. |
format |
Other/Unknown Material |
author |
Piketh, S. J. Hyer, E. J. Holben, B. N. Jethva, H. T. Torres, O. Sorokin, M. Sinyuk, A. Reid, J. S. Ward, D. E. Giles, D. M. Dubovik, O. Eck, T. F. Slutsker, I. Mukelabai, M. M. Smirnov, A. Schafer, J. S. |
author_facet |
Piketh, S. J. Hyer, E. J. Holben, B. N. Jethva, H. T. Torres, O. Sorokin, M. Sinyuk, A. Reid, J. S. Ward, D. E. Giles, D. M. Dubovik, O. Eck, T. F. Slutsker, I. Mukelabai, M. M. Smirnov, A. Schafer, J. S. |
author_sort |
Piketh, S. J. |
title |
A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source |
title_short |
A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source |
title_full |
A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source |
title_fullStr |
A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source |
title_full_unstemmed |
A Seasonal Trend of Single Scattering Albedo in Southern African Biomass-burning Particles: Implications for Satellite Products and Estimates of Emissions for the World's Largest Biomass-burning Source |
title_sort |
seasonal trend of single scattering albedo in southern african biomass-burning particles: implications for satellite products and estimates of emissions for the world's largest biomass-burning source |
publishDate |
2013 |
url |
http://hdl.handle.net/2060/20140016775 |
op_coverage |
Unclassified, Unlimited, Publicly available |
genre |
Aerosol Robotic Network |
genre_facet |
Aerosol Robotic Network |
op_source |
CASI |
op_relation |
Document ID: 20140016775 http://hdl.handle.net/2060/20140016775 |
op_rights |
Copyright, Distribution as joint owner in the copyright |
_version_ |
1766020030571479040 |