A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow
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 o...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2017-02-01
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| Series: | Journal of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S002214301600126X/type/journal_article |
| _version_ | 1827994505016508416 |
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| author | S. McKENZIE SKILES THOMAS PAINTER GREGORY S. OKIN |
| author_facet | S. McKENZIE SKILES THOMAS PAINTER GREGORY S. OKIN |
| author_sort | S. McKENZIE SKILES |
| collection | DOAJ |
| description | 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 kλ 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%. |
| first_indexed | 2024-04-10T04:41:59Z |
| format | Article |
| id | doaj.art-9d16bda1f1b54c5289004ff665b26a7b |
| institution | Directory Open Access Journal |
| issn | 0022-1430 1727-5652 |
| language | English |
| last_indexed | 2024-04-10T04:41:59Z |
| publishDate | 2017-02-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj.art-9d16bda1f1b54c5289004ff665b26a7b2023-03-09T12:40:19ZengCambridge University PressJournal of Glaciology0022-14301727-56522017-02-016313314710.1017/jog.2016.126A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snowS. McKENZIE SKILES0THOMAS PAINTER1GREGORY S. OKIN2Department of Earth Science, Utah Valley University, Orem, UT, USA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA Joint Institute for Regional Earth System Science and Engineering, University of California, Los Angeles, California, USAJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA Joint Institute for Regional Earth System Science and Engineering, University of California, Los Angeles, California, USADepartment of Geography, University of California Los Angeles, Los Angeles, CA, USADust 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 kλ 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%.https://www.cambridge.org/core/product/identifier/S002214301600126X/type/journal_articleenergy balanceice/atmosphere interactionssnow/ice surface processessnow |
| spellingShingle | S. McKENZIE SKILES THOMAS PAINTER GREGORY S. OKIN A method to retrieve the spectral complex refractive index and single scattering optical properties of dust deposited in mountain snow Journal of Glaciology energy balance ice/atmosphere interactions snow/ice surface processes snow |
| title | 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_short | 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 |
| topic | energy balance ice/atmosphere interactions snow/ice surface processes snow |
| url | https://www.cambridge.org/core/product/identifier/S002214301600126X/type/journal_article |
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