A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow
ABSTRACT Dust deposition to snow can have regionally important climatic and hydrologic impacts resulting from direct reduction of surface albedo and indirectly from the initiation of snow albedo feedbacks. Modeling the radiative impacts of dust deposited in snow requires knowledge of the optical pro...
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crcambridgeupr:10.1017/jog.2016.126 2024-06-23T07:54:15+00:00 A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow SKILES, S. McKENZIE PAINTER, THOMAS OKIN, GREGORY S. 2016 http://dx.doi.org/10.1017/jog.2016.126 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214301600126X en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Journal of Glaciology volume 63, issue 237, page 133-147 ISSN 0022-1430 1727-5652 journal-article 2016 crcambridgeupr https://doi.org/10.1017/jog.2016.126 2024-06-12T04:04:24Z ABSTRACT Dust deposition to snow can have regionally important climatic and hydrologic impacts resulting from direct reduction of surface albedo and indirectly from the initiation of snow albedo feedbacks. Modeling the radiative impacts of dust deposited in snow requires knowledge of the optical properties of both components. Here we present an inversion technique to retrieve the effective optical properties of dust deposited in mountain snow cover from measurements of hemispherical dust reflectance and particle size distributions using radiative transfer modeling. First, modeled reflectance is produced from single scattering properties modeled with Mie theory for a specified grain size distribution over a range of values for the imaginary part of the complex refractive index ( k = 0.00001–0.1). Then, a multi-step look-up table process is employed to retrieve k λ and single scattering optical properties by matching measured to modeled reflectance across the shortwave and near infrared. The real part of the complex refractive index, n , for dust aerosols ranges between 1.5 and 1.6 and a sensitivity analysis shows the method is relatively insensitive to the choice of n within this range, 1.525 was used here. Using the values retrieved by this method to update dust optical properties in a snow + aerosol radiative transfer model reduces errors in springtime albedo modeling by 50–70%. Article in Journal/Newspaper Journal of Glaciology Cambridge University Press Journal of Glaciology 63 237 133 147 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
ABSTRACT Dust deposition to snow can have regionally important climatic and hydrologic impacts resulting from direct reduction of surface albedo and indirectly from the initiation of snow albedo feedbacks. Modeling the radiative impacts of dust deposited in snow requires knowledge of the optical properties of both components. Here we present an inversion technique to retrieve the effective optical properties of dust deposited in mountain snow cover from measurements of hemispherical dust reflectance and particle size distributions using radiative transfer modeling. First, modeled reflectance is produced from single scattering properties modeled with Mie theory for a specified grain size distribution over a range of values for the imaginary part of the complex refractive index ( k = 0.00001–0.1). Then, a multi-step look-up table process is employed to retrieve k λ and single scattering optical properties by matching measured to modeled reflectance across the shortwave and near infrared. The real part of the complex refractive index, n , for dust aerosols ranges between 1.5 and 1.6 and a sensitivity analysis shows the method is relatively insensitive to the choice of n within this range, 1.525 was used here. Using the values retrieved by this method to update dust optical properties in a snow + aerosol radiative transfer model reduces errors in springtime albedo modeling by 50–70%. |
format |
Article in Journal/Newspaper |
author |
SKILES, S. McKENZIE PAINTER, THOMAS OKIN, GREGORY S. |
spellingShingle |
SKILES, S. McKENZIE PAINTER, THOMAS OKIN, GREGORY S. A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow |
author_facet |
SKILES, S. McKENZIE PAINTER, THOMAS OKIN, GREGORY S. |
author_sort |
SKILES, S. McKENZIE |
title |
A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow |
title_short |
A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow |
title_full |
A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow |
title_fullStr |
A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow |
title_full_unstemmed |
A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow |
title_sort |
method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow |
publisher |
Cambridge University Press (CUP) |
publishDate |
2016 |
url |
http://dx.doi.org/10.1017/jog.2016.126 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S002214301600126X |
genre |
Journal of Glaciology |
genre_facet |
Journal of Glaciology |
op_source |
Journal of Glaciology volume 63, issue 237, page 133-147 ISSN 0022-1430 1727-5652 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/jog.2016.126 |
container_title |
Journal of Glaciology |
container_volume |
63 |
container_issue |
237 |
container_start_page |
133 |
op_container_end_page |
147 |
_version_ |
1802646360088903680 |