Aerosol single-scattering albedo retrieval over North Africa using critical reflectance
2010 Fall. Includes bibliographical references. The sign and magnitude of the aerosol radiative forcing over bright surfaces is highly dependent on the absorbing properties of the aerosol. Thus, the determination of aerosol forcing over desert regions requires accurate information about the aerosol...
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ftcolostateunidc:oai:mountainscholar.org:10217/44973 2023-06-11T04:03:04+02:00 Aerosol single-scattering albedo retrieval over North Africa using critical reflectance Wells, Kelley Carlene Kreidenweis, Sonia M. Stephens, Graeme L., 1952- Remer, Lorraine Ann Collett, Jeffrey L. Peel, Jennifer L. North Africa 2007-01-03T04:52:20Z born digital doctoral dissertations application/pdf http://hdl.handle.net/10217/44973 English eng eng Colorado State University. Libraries 2000-2019 - CSU Theses and Dissertations Wells_colostate_0053A_10116.pdf ETDF2010100011ATMS http://hdl.handle.net/10217/44973 Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. remote sensing radiative forcing dust biomass burning aerosol absorption Atmospheric aerosols -- North Africa -- Remote sensing Artificial satellites in remote sensing -- North Africa Albedo -- Remote sensing Biomass -- Combustion -- North Africa Text 2007 ftcolostateunidc 2023-05-04T17:39:32Z 2010 Fall. Includes bibliographical references. The sign and magnitude of the aerosol radiative forcing over bright surfaces is highly dependent on the absorbing properties of the aerosol. Thus, the determination of aerosol forcing over desert regions requires accurate information about the aerosol single-scattering albedo (SSA). However, the brightness of desert surfaces complicates the retrieval of aerosol optical properties using passive space-based measurements. The aerosol critical reflectance is one parameter that can be used to relate top-of-atmosphere (TOA) reflectance changes over land to the aerosol absorption properties, without knowledge of the underlying surface properties or aerosol loading. Physically, the parameter represents the TOA reflectance at which increased aerosol scattering due to increased aerosol loading is balanced by increased absorption of the surface contribution to the TOA reflectance. It can be derived by comparing two satellite images with different aerosol loading, assuming that the surface reflectance and background aerosol are similar between the two days. In this work, we explore the utility of the critical reflectance method for routine monitoring of spectral aerosol absorption from space over North Africa, a region that is predominantly impacted by absorbing dust and biomass burning aerosol. We derive the critical reflectance from Moderate Resolution Spectroradiometer (MODIS) Level 1B reflectances in the vicinity of two Aerosol Robotic Network (AERONET) stations: Tamanrasset, a site in the Algerian Sahara, and Banizoumbou, a Sahelian site in Niger. We examine the sensitivity of the critical reflectance parameter to aerosol physical and optical properties, as well as solar and viewing geometry, using the Santa Barbara DISORT Radiative Transfer (SBDART) model, and apply our findings to retrieve SSA from the MODIS critical reflectance values. We compare our results to AERONET-retrieved estimates, as well as to measurements of the TOA albedo and surface fluxes from the ... Text Aerosol Robotic Network Digital Collections of Colorado (Colorado State University) |
institution |
Open Polar |
collection |
Digital Collections of Colorado (Colorado State University) |
op_collection_id |
ftcolostateunidc |
language |
English |
topic |
remote sensing radiative forcing dust biomass burning aerosol absorption Atmospheric aerosols -- North Africa -- Remote sensing Artificial satellites in remote sensing -- North Africa Albedo -- Remote sensing Biomass -- Combustion -- North Africa |
spellingShingle |
remote sensing radiative forcing dust biomass burning aerosol absorption Atmospheric aerosols -- North Africa -- Remote sensing Artificial satellites in remote sensing -- North Africa Albedo -- Remote sensing Biomass -- Combustion -- North Africa Wells, Kelley Carlene Aerosol single-scattering albedo retrieval over North Africa using critical reflectance |
topic_facet |
remote sensing radiative forcing dust biomass burning aerosol absorption Atmospheric aerosols -- North Africa -- Remote sensing Artificial satellites in remote sensing -- North Africa Albedo -- Remote sensing Biomass -- Combustion -- North Africa |
description |
2010 Fall. Includes bibliographical references. The sign and magnitude of the aerosol radiative forcing over bright surfaces is highly dependent on the absorbing properties of the aerosol. Thus, the determination of aerosol forcing over desert regions requires accurate information about the aerosol single-scattering albedo (SSA). However, the brightness of desert surfaces complicates the retrieval of aerosol optical properties using passive space-based measurements. The aerosol critical reflectance is one parameter that can be used to relate top-of-atmosphere (TOA) reflectance changes over land to the aerosol absorption properties, without knowledge of the underlying surface properties or aerosol loading. Physically, the parameter represents the TOA reflectance at which increased aerosol scattering due to increased aerosol loading is balanced by increased absorption of the surface contribution to the TOA reflectance. It can be derived by comparing two satellite images with different aerosol loading, assuming that the surface reflectance and background aerosol are similar between the two days. In this work, we explore the utility of the critical reflectance method for routine monitoring of spectral aerosol absorption from space over North Africa, a region that is predominantly impacted by absorbing dust and biomass burning aerosol. We derive the critical reflectance from Moderate Resolution Spectroradiometer (MODIS) Level 1B reflectances in the vicinity of two Aerosol Robotic Network (AERONET) stations: Tamanrasset, a site in the Algerian Sahara, and Banizoumbou, a Sahelian site in Niger. We examine the sensitivity of the critical reflectance parameter to aerosol physical and optical properties, as well as solar and viewing geometry, using the Santa Barbara DISORT Radiative Transfer (SBDART) model, and apply our findings to retrieve SSA from the MODIS critical reflectance values. We compare our results to AERONET-retrieved estimates, as well as to measurements of the TOA albedo and surface fluxes from the ... |
author2 |
Kreidenweis, Sonia M. Stephens, Graeme L., 1952- Remer, Lorraine Ann Collett, Jeffrey L. Peel, Jennifer L. |
format |
Text |
author |
Wells, Kelley Carlene |
author_facet |
Wells, Kelley Carlene |
author_sort |
Wells, Kelley Carlene |
title |
Aerosol single-scattering albedo retrieval over North Africa using critical reflectance |
title_short |
Aerosol single-scattering albedo retrieval over North Africa using critical reflectance |
title_full |
Aerosol single-scattering albedo retrieval over North Africa using critical reflectance |
title_fullStr |
Aerosol single-scattering albedo retrieval over North Africa using critical reflectance |
title_full_unstemmed |
Aerosol single-scattering albedo retrieval over North Africa using critical reflectance |
title_sort |
aerosol single-scattering albedo retrieval over north africa using critical reflectance |
publisher |
Colorado State University. Libraries |
publishDate |
2007 |
url |
http://hdl.handle.net/10217/44973 |
op_coverage |
North Africa |
genre |
Aerosol Robotic Network |
genre_facet |
Aerosol Robotic Network |
op_relation |
2000-2019 - CSU Theses and Dissertations Wells_colostate_0053A_10116.pdf ETDF2010100011ATMS http://hdl.handle.net/10217/44973 |
op_rights |
Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. |
_version_ |
1768373014402957312 |