Retrieval of aerosol optical depth over land surfaces from AVHRR data
The Advanced Very High Resolution Radiometer (AVHRR) provides a global, long-term, consistent time series of radiance data in several wavebands which are used for the retrieval of surface spectral reflectance, albedo and surface temperature. Long-term time series of such data products are necessary...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-08-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/7/2411/2014/amt-7-2411-2014.pdf |
| _version_ | 1818146765246824448 |
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| author | L. L. Mei Y. Xue A. A. Kokhanovsky W. von Hoyningen-Huene G. de Leeuw J. P. Burrows |
| author_facet | L. L. Mei Y. Xue A. A. Kokhanovsky W. von Hoyningen-Huene G. de Leeuw J. P. Burrows |
| author_sort | L. L. Mei |
| collection | DOAJ |
| description | The Advanced Very High Resolution Radiometer (AVHRR) provides a global,
long-term, consistent time series of radiance data in several wavebands which
are used for the retrieval of surface spectral reflectance, albedo and
surface temperature. Long-term time series of such data products are
necessary for studies addressing climate change, sea ice distribution and
movement, and ice sheet coastal configuration. AVHRR radiances have also been
used to retrieve aerosol properties over ocean and land surfaces. However,
the retrieval of aerosol over land is challenging because of the limited
information content in the data which renders the inversion problem ill
defined. Solving the radiative transfer equations requires additional
information to reduce the number of unknowns. In this contribution we utilise
an empirical linear relationship between the surface reflectances in the
AVHRR channels at wavelengths of 3.75 μm and 2.1 μm,
which has been identified in the Moderate Resolution Imaging
Spectroradiometer (MODIS) data. Following the MODIS dark target approach,
this relationship is used to obtain the surface reflectance at
0.64 μm. The comparison of the estimated surface reflectances with
MODIS reflectance products (MOD09) shows a strong correlation. Once this was
established, the MODIS "dark-target" aerosol retrieval method was adapted
to AVHRR data. A simplified look-up table (LUT) method, adopted from the
Bremen AErosol Retrieval (BAER) algorithm, was used in the retrieval. The
aerosol optical depth (AOD) values retrieved from AVHRR with this method
compare favourably with ground-based measurements, with 71.8% of the
points located within ±(0.1 + 0.15τ) (τ is the AOD) of the
identity line. This method can be easily applied to other satellite
instruments which do not have a 2.1 μm channel, such as those
currently planned to be used on geostationary satellites. |
| first_indexed | 2024-12-11T12:24:33Z |
| format | Article |
| id | doaj.art-9f0fccc8f90c4e6593d232ba33895b35 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-11T12:24:33Z |
| publishDate | 2014-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-9f0fccc8f90c4e6593d232ba33895b352022-12-22T01:07:27ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482014-08-01782411242010.5194/amt-7-2411-2014Retrieval of aerosol optical depth over land surfaces from AVHRR dataL. L. Mei0Y. Xue1A. A. Kokhanovsky2W. von Hoyningen-Huene3G. de Leeuw4J. P. Burrows5The Key Laboratory of Digital Earth Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100094, ChinaThe Key Laboratory of Digital Earth Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100094, ChinaInstitute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, GermanyInstitute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, GermanyDepartment of Physics, University of Helsinki, Helsinki, FinlandInstitute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, GermanyThe Advanced Very High Resolution Radiometer (AVHRR) provides a global, long-term, consistent time series of radiance data in several wavebands which are used for the retrieval of surface spectral reflectance, albedo and surface temperature. Long-term time series of such data products are necessary for studies addressing climate change, sea ice distribution and movement, and ice sheet coastal configuration. AVHRR radiances have also been used to retrieve aerosol properties over ocean and land surfaces. However, the retrieval of aerosol over land is challenging because of the limited information content in the data which renders the inversion problem ill defined. Solving the radiative transfer equations requires additional information to reduce the number of unknowns. In this contribution we utilise an empirical linear relationship between the surface reflectances in the AVHRR channels at wavelengths of 3.75 μm and 2.1 μm, which has been identified in the Moderate Resolution Imaging Spectroradiometer (MODIS) data. Following the MODIS dark target approach, this relationship is used to obtain the surface reflectance at 0.64 μm. The comparison of the estimated surface reflectances with MODIS reflectance products (MOD09) shows a strong correlation. Once this was established, the MODIS "dark-target" aerosol retrieval method was adapted to AVHRR data. A simplified look-up table (LUT) method, adopted from the Bremen AErosol Retrieval (BAER) algorithm, was used in the retrieval. The aerosol optical depth (AOD) values retrieved from AVHRR with this method compare favourably with ground-based measurements, with 71.8% of the points located within ±(0.1 + 0.15τ) (τ is the AOD) of the identity line. This method can be easily applied to other satellite instruments which do not have a 2.1 μm channel, such as those currently planned to be used on geostationary satellites.http://www.atmos-meas-tech.net/7/2411/2014/amt-7-2411-2014.pdf |
| spellingShingle | L. L. Mei Y. Xue A. A. Kokhanovsky W. von Hoyningen-Huene G. de Leeuw J. P. Burrows Retrieval of aerosol optical depth over land surfaces from AVHRR data Atmospheric Measurement Techniques |
| title | Retrieval of aerosol optical depth over land surfaces from AVHRR data |
| title_full | Retrieval of aerosol optical depth over land surfaces from AVHRR data |
| title_fullStr | Retrieval of aerosol optical depth over land surfaces from AVHRR data |
| title_full_unstemmed | Retrieval of aerosol optical depth over land surfaces from AVHRR data |
| title_short | Retrieval of aerosol optical depth over land surfaces from AVHRR data |
| title_sort | retrieval of aerosol optical depth over land surfaces from avhrr data |
| url | http://www.atmos-meas-tech.net/7/2411/2014/amt-7-2411-2014.pdf |
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