Aerosol models from the AERONET database: application to surface reflectance validation
<p>Aerosols play a critical role in radiative transfer within the atmosphere, and they have a significant impact on climate change. In this paper, we propose and implement a framework for developing an aerosol model using their microphysical properties. Such microphysical properties as the siz...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-03-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/15/1123/2022/amt-15-1123-2022.pdf |
| _version_ | 1818908503453990912 |
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| author | J.-C. Roger J.-C. Roger E. Vermote S. Skakun S. Skakun E. Murphy E. Murphy O. Dubovik N. Kalecinski N. Kalecinski B. Korgo B. Holben |
| author_facet | J.-C. Roger J.-C. Roger E. Vermote S. Skakun S. Skakun E. Murphy E. Murphy O. Dubovik N. Kalecinski N. Kalecinski B. Korgo B. Holben |
| author_sort | J.-C. Roger |
| collection | DOAJ |
| description | <p>Aerosols play a critical role in radiative transfer within the
atmosphere, and they have a significant impact on climate change. In this
paper, we propose and implement a framework for developing an aerosol model
using their microphysical properties. Such microphysical properties as the
size distribution, the complex refractive index, and the percentage of
sphericity are derived from the global AERosol RObotic NETwork (AERONET).
These measurements, however, are typically retrieved when almucantar
measurement procedures are performed (i.e., early mornings and late
afternoons with clear sky) and might not have a temporal correspondence to
a satellite overpass time, so a valid validation of satellite-derived
products cannot be carried out. To address this problem of temporal
inconsistency of satellite and ground-based measurements, we developed an
approach to retrieve these microphysical properties (and the corresponding
aerosol model) using the optical thickness at 440 nm, <span class="inline-formula"><i>τ</i><sub>440</sub></span>, and
the Ångström coefficient between 440 and 870 nm, <span class="inline-formula"><i>α</i><sub>440–870</sub></span>. Such aerosol models were developed for 851 AERONET sites within the last 28 years. Obtained results
suggest that empirically microphysical properties can be retrieved with
uncertainties of up to 23 %. An exception is the imaginary part of the
refractive index ni, for which the derived uncertainties reach up to 38 %. These specific parametric models of aerosol can be used for the studies when
retrieval of microphysical properties is required as well as validation of
satellite-derived products over land. Specifically, we demonstrate the
usefulness of the aerosol models to validate surface reflectance records
over land derived from optical remote sensing sensors. We then quantify the
propagation of uncertainties in the surface
reflectance due to uncertainties with the aerosol model retrieval that is used as a reference from radiative transfer simulations. Results indicate that individual aerosol microphysical properties can impact uncertainties in surface reflectance retrievals between
3.5 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>−5</sup></span> to 1 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>−3</sup></span> (in reflectance units). The overall impact of
microphysical properties combined yields an overall uncertainty in surface
reflectance <span class="inline-formula"><</span> 0.004 (in reflectance units). That corresponds, for
example, to 1 to 3 % of the retrieved surface reflectance in the red
spectral band (620–670 nm) by the Moderate Resolution Imaging
Spectroradiometer (MODIS) instrument. These uncertainty values are well
below the specification (0.005 <span class="inline-formula">+</span> 0.05<span class="inline-formula"><i>ρ</i></span>; <span class="inline-formula"><i>ρ</i></span> is the retrieved
surface reflectance) used for the MODIS atmospheric correction.</p> |
| first_indexed | 2024-12-19T22:12:03Z |
| format | Article |
| id | doaj.art-df052130f31944a38fdce9220a84f633 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-19T22:12:03Z |
| publishDate | 2022-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-df052130f31944a38fdce9220a84f6332022-12-21T20:03:53ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482022-03-01151123114410.5194/amt-15-1123-2022Aerosol models from the AERONET database: application to surface reflectance validationJ.-C. Roger0J.-C. Roger1E. Vermote2S. Skakun3S. Skakun4E. Murphy5E. Murphy6O. Dubovik7N. Kalecinski8N. Kalecinski9B. Korgo10B. Holben11Department of Geographical Sciences, University of Maryland, College Park, MD 20742, USATerrestrial Information Systems Laboratory (Branch Code 619), Goddard Space Flight Center, NASA, Greenbelt, MD 20771, USATerrestrial Information Systems Laboratory (Branch Code 619), Goddard Space Flight Center, NASA, Greenbelt, MD 20771, USADepartment of Geographical Sciences, University of Maryland, College Park, MD 20742, USATerrestrial Information Systems Laboratory (Branch Code 619), Goddard Space Flight Center, NASA, Greenbelt, MD 20771, USADepartment of Geographical Sciences, University of Maryland, College Park, MD 20742, USATerrestrial Information Systems Laboratory (Branch Code 619), Goddard Space Flight Center, NASA, Greenbelt, MD 20771, USALaboratoire d'Optique Atmosphérique, Université de Lille 1, Villeneuve d'Ascq, 59665, FranceDepartment of Geographical Sciences, University of Maryland, College Park, MD 20742, USATerrestrial Information Systems Laboratory (Branch Code 619), Goddard Space Flight Center, NASA, Greenbelt, MD 20771, USALaboratory of Thermal and Renewable Energy, Université Joseph KI-ZERBO, Ouagadougou, Burkina FasoBiospheric Sciences Laboratory (Branch Code 618), Goddard Space Flight Center, NASA, Greenbelt, MD 20771, USA<p>Aerosols play a critical role in radiative transfer within the atmosphere, and they have a significant impact on climate change. In this paper, we propose and implement a framework for developing an aerosol model using their microphysical properties. Such microphysical properties as the size distribution, the complex refractive index, and the percentage of sphericity are derived from the global AERosol RObotic NETwork (AERONET). These measurements, however, are typically retrieved when almucantar measurement procedures are performed (i.e., early mornings and late afternoons with clear sky) and might not have a temporal correspondence to a satellite overpass time, so a valid validation of satellite-derived products cannot be carried out. To address this problem of temporal inconsistency of satellite and ground-based measurements, we developed an approach to retrieve these microphysical properties (and the corresponding aerosol model) using the optical thickness at 440 nm, <span class="inline-formula"><i>τ</i><sub>440</sub></span>, and the Ångström coefficient between 440 and 870 nm, <span class="inline-formula"><i>α</i><sub>440–870</sub></span>. Such aerosol models were developed for 851 AERONET sites within the last 28 years. Obtained results suggest that empirically microphysical properties can be retrieved with uncertainties of up to 23 %. An exception is the imaginary part of the refractive index ni, for which the derived uncertainties reach up to 38 %. These specific parametric models of aerosol can be used for the studies when retrieval of microphysical properties is required as well as validation of satellite-derived products over land. Specifically, we demonstrate the usefulness of the aerosol models to validate surface reflectance records over land derived from optical remote sensing sensors. We then quantify the propagation of uncertainties in the surface reflectance due to uncertainties with the aerosol model retrieval that is used as a reference from radiative transfer simulations. Results indicate that individual aerosol microphysical properties can impact uncertainties in surface reflectance retrievals between 3.5 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>−5</sup></span> to 1 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>−3</sup></span> (in reflectance units). The overall impact of microphysical properties combined yields an overall uncertainty in surface reflectance <span class="inline-formula"><</span> 0.004 (in reflectance units). That corresponds, for example, to 1 to 3 % of the retrieved surface reflectance in the red spectral band (620–670 nm) by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. These uncertainty values are well below the specification (0.005 <span class="inline-formula">+</span> 0.05<span class="inline-formula"><i>ρ</i></span>; <span class="inline-formula"><i>ρ</i></span> is the retrieved surface reflectance) used for the MODIS atmospheric correction.</p>https://amt.copernicus.org/articles/15/1123/2022/amt-15-1123-2022.pdf |
| spellingShingle | J.-C. Roger J.-C. Roger E. Vermote S. Skakun S. Skakun E. Murphy E. Murphy O. Dubovik N. Kalecinski N. Kalecinski B. Korgo B. Holben Aerosol models from the AERONET database: application to surface reflectance validation Atmospheric Measurement Techniques |
| title | Aerosol models from the AERONET database: application to surface reflectance validation |
| title_full | Aerosol models from the AERONET database: application to surface reflectance validation |
| title_fullStr | Aerosol models from the AERONET database: application to surface reflectance validation |
| title_full_unstemmed | Aerosol models from the AERONET database: application to surface reflectance validation |
| title_short | Aerosol models from the AERONET database: application to surface reflectance validation |
| title_sort | aerosol models from the aeronet database application to surface reflectance validation |
| url | https://amt.copernicus.org/articles/15/1123/2022/amt-15-1123-2022.pdf |
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