Accuracy assessment of MODIS land aerosol optical thickness algorithms using AERONET measurements over North America
<p>The planned simultaneous availability of visible and near-IR observations from the geostationary platforms of Tropospheric Emissions: Monitoring of Pollution (TEMPO) and Geostationary Operational Environmental Satellites (GOES) 16/17 Advanced Base Imager (ABI) will present the opportunity o...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-08-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/12/4291/2019/amt-12-4291-2019.pdf |
| Summary: | <p>The planned simultaneous availability of visible and near-IR observations
from the geostationary platforms of Tropospheric Emissions: Monitoring of
Pollution (TEMPO) and Geostationary Operational Environmental Satellites
(GOES) 16/17 Advanced Base Imager (ABI) will present the opportunity of
deriving an accurate aerosol product taking advantage of both ABI's high
spatial resolution in the visible range and TEMPO's sensitivity to aerosol
absorption in the near-UV range. Because the wavelengths of ABI are similar to
those of the Moderate Resolution Imaging Spectroradiometer (MODIS), existing
aerosol algorithms of MODIS can be applied to ABI observations. In this
work, we evaluate three distinct aerosol algorithms of MODIS deriving
aerosol optical thickness (AOT) over land surfaces using visible and near-IR
observations. The Dark Target (DT), Deep Blue (DB), and Multiangle
Implementation of Atmospheric Correction (MAIAC) algorithms are all applied
to the radiance measurements of MODIS on board the Aqua satellite. We have
evaluated each algorithm by comparing the satellite-retrieved AOT to
space-time collocated ground-based sun photometer measurements of the same
parameter at 171 sites of the Aerosol Robotic Network (AERONET) over North
America (NA). A spatiotemporal scheme collocating the satellite retrievals
with the ground-based measurements was applied consistently to all three
retrieval datasets. We find that the statistical performance of all three
algorithms is comparable over darker surfaces over eastern NA with the MAIAC
algorithm providing relatively better comparison over western NA sites
characterized by inhomogeneous elevation and bright surfaces. The higher
spatial resolution of the MAIAC product (1 km) allows a substantially larger
number of matchups than DB 10 km and DT 10 km (DT 3 km) products by 115 %
and 120 % (86 %), respectively, over eastern NA and by 150 % and
220 % (197 %) over western NA. The characterization of the error in AOT
for the three aerosol products as a function of bidirectional surface
reflectance derived from both MAIAC and an
independent MOD09 atmospheric correction shows a systematic positive bias in DT retrievals over brighter
surfaces, whereas DB and MAIAC retrievals show no such bias throughout the
wide range of surface brightness, with MAIAC offering the lowest spread in
errors. The results reported here represent an objective, unbiased
evaluation of existing over-land aerosol retrieval algorithms of MODIS. The
detailed statistical evaluation of the performance of each of these three
algorithms may be used as guidance in the development of inversion schemes
to derive aerosol properties from ABI or other MODIS-like sensors.</p> |
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| ISSN: | 1867-1381 1867-8548 |