MODIS 3 km aerosol product: applications over land in an urban/suburban region

Munchak, L. A.; Levy, Robert C.; Mattoo, S.; Remer, L. A.; Holben, B. N.; Schafer, J. S.; Hostetler, C. A.; Ferrare, R. A.

doi:10.5194/amt-6-1747-2013

Cited by 156 publications

(135 citation statements)

References 38 publications

(45 reference statements)

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“…Future work that applies the MODIS 3 km aerosol product to local aerosol situations in case studies and evaluates the results will be necessary to continue the work started here (ie. Munchak et al, 2013). We expect the new 3 km product to provide important information complementary to existing satellite-derived products and become an important tool for the aerosol community.…”

Section: Discussionmentioning

confidence: 99%

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MODIS 3 km aerosol product: algorithm and global perspective

et al. 2013

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After more than a decade of producing a nominal 10 km aerosol product based on the dark target method, the MODerate resolution Imaging Spectroradiometer (MODIS) aerosol team will be releasing a nominal 3 km product as part of their Collection 6 release. The new product differs from the original 10 km product only in the manner in which reflectance pixels are ingested, organized and selected by the aerosol algorithm. Overall, the 3 km product closely mirrors the 10 km product. However, the finer resolution product is able to retrieve over the ocean closer to islands and coastlines, and is better able to resolve fine aerosol features such as smoke plumes over both ocean and land. In some situations, it provides retrievals over entire regions that the 10 km product barely samples. In situations traditionally difficult for the dark target algorithm such as over bright or urban surfaces, the 3 km product introduces isolated spikes of artificially high aerosol optical depth (AOD) that the 10 km algorithm avoids. Over land, globally, the 3 km product appears to be 0.01 to 0.02 higher than the 10 km product, while over ocean, the 3 km algorithm is retrieving a proportionally greater number of very low aerosol loading situations. Based on collocations with ground-based observations for only six months, expected errors associated with the 3 km land product are determined to be greater than that of the 10 km product: ± 0.05 ± 0.20 AOD. Over ocean, the suggestion is for expected errors to be the same as the 10 km product: ± 0.03 ± 0.05 AOD, but slightly less accurate in the coastal zone. The advantage of the product is on the local scale, which will require continued evaluation not addressed here. Nevertheless, the new 3 km product is expected to provide important information complementary to existing satellite-derived products and become an important tool for the aerosol community

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Section: Discussionmentioning

confidence: 99%

“…The MODIS Dark Target aerosol algorithms are well documented in the literature Tanré et al, 1997;Remer et al, 2005Remer et al, , 2012Levy et al, 2007aLevy et al, , b, 2013). …”

Section: Modis Aerosol Retrieval At 10 Km and 3 Km Resolutionmentioning

confidence: 99%

MODIS 3 km aerosol product: algorithm and global perspective

et al. 2013

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“…MDT does not provide aerosol retrieval over very bright surface (i.e., desert) and over snow and ice regions. In addition, several validation studies have shown that MDT AOD retrievals over urban area are positively biased with respect to AERONET AODs Jethva et al, 2007;Hyer et al, 2011;Gupta et al, 2013;Munchak et al, 2013). These studies have shown that the major source of bias in the MDT over cities is that the city surface does not behave as a vegetated "dark" target.…”

Section: Introductionmentioning

confidence: 99%

“…In the recent release of MODIS Collection 6 (C6) data version, there is also a MxD04_3K product, which is at 3 km spatial resolution (nadir) and available globally. The standard C6 products have gone through initial validation (e.g., Levy et al, 2013;Munchak et al, 2013;Remer et al, 2013).…”

Section: Modis and The Dark Target Algorithmmentioning

confidence: 99%

A surface reflectance scheme for retrieving aerosol optical depth over urban surfaces in MODIS Dark Target retrieval algorithm

et al. 2016

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Abstract. The MODerate resolution Imaging Spectroradiometer (MODIS) instruments, aboard the two Earth Observing System (EOS) satellites Terra and Aqua, provide aerosol information with nearly daily global coverage at moderate spatial resolution (10 and 3 km). Almost 15 years of aerosol data records are now available from MODIS that can be used for various climate and air-quality applications. However, the application of MODIS aerosol products for airquality concerns is limited by a reduction in retrieval accuracy over urban surfaces. This is largely because the urban surface reflectance behaves differently than that assumed for natural surfaces. In this study, we address the inaccuracies produced by the MODIS Dark Target (MDT) algorithm aerosol optical depth (AOD) retrievals over urban areas and suggest improvements by modifying the surface reflectance scheme in the algorithm. By integrating MODIS Land Surface Reflectance and Land Cover Type information into the aerosol surface parameterization scheme for urban areas, much of the issues associated with the standard algorithm have been mitigated for our test region, the continental United States (CONUS). The new surface scheme takes into account the change in underlying surface type and is only applied for MODIS pixels with urban percentage (UP) larger than 20 %. Over the urban areas where the new scheme has been applied (UP > 20 %), the number of AOD retrievals falling within expected error (EE %) has increased by 20 %, and the strong positive bias against ground-based sun photometry has been eliminated. However, we note that the new retrieval introduces a small negative bias for AOD values less than 0.1 due to the ultra-sensitivity of the AOD retrieval to the surface parameterization under low atmospheric aerosol loadings. Global application of the new urban surface parameterization appears promising, but further research and analysis are required before global implementation.

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“…For slope, RMSE, MBE, and % within EE, GOCI is better than that of MODIS DT. Munchak et al (2013) described that MODIS DT Collection 6 AOD is biased high over urban surfaces, and it is suspected due to the inaccurate surface reflectance over urban in the MODIS DT operational retrievals. Otherwise, the enhanced MODIS DB algorithm (Collection 6) shows the best result, which controls surface reflectance differently according to surface type, giving high accuracy regardless of surface type .…”

Section: Validation Of Aodmentioning

confidence: 99%

GOCI Yonsei Aerosol Retrieval (YAER) algorithm and validation during the DRAGON-NE Asia 2012 campaign

et al. 2016

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Abstract. The Geostationary Ocean Color Imager (GOCI) onboard the Communication, Ocean, and Meteorological Satellite (COMS) is the first multi-channel ocean color imager in geostationary orbit. Hourly GOCI top-of-atmosphere radiance has been available for the retrieval of aerosol optical properties over East Asia since March 2011. This study presents improvements made to the GOCI Yonsei Aerosol Retrieval (YAER) algorithm together with validation results during the Distributed Regional Aerosol Gridded Observation Networks -Northeast Asia 2012 campaign (DRAGON-NE Asia 2012 campaign). The evaluation during the spring season over East Asia is important because of high aerosol concentrations and diverse types of Asian dust and haze. Optical properties of aerosol are retrieved from the GOCI YAER algorithm including aerosol optical depth (AOD) at 550 nm, fine-mode fraction (FMF) at 550 nm, single-scattering albedo (SSA) at 440 nm, Ångström exponent (AE) between 440 and 860 nm, and aerosol type. The aerosol models are created based on a global analysis of the Aerosol Robotic Networks (AERONET) inversion data, and covers a broad range of size distribution and absorptivity, including nonspherical dust properties. The Cox-Munk ocean bidirectional reflectance distribution function (BRDF) model is used over ocean, and an improved minimum reflectance technique is used over land. Because turbid water is persistent over the Yellow Sea, the land algorithm is used for such cases. The aerosol products are evaluated against AERONET observations and MODIS Collection 6 aerosol products retrieved from Dark Target (DT) and Deep Blue (DB) algorithms during the DRAGON-NE Asia 2012 campaign conducted from March to May 2012. Comparison of AOD from GOCI and AERONET resulted in a Pearson correlation coefficient of 0.881 and a linear regression equation with GOCI AOD = 1.083 × AERONET AOD − 0.042. The correlation between GOCI and MODIS AODs is higher over ocean than land. GOCI AOD shows better agreement with MODIS DB than MODIS DT. The other GOCI YAER products (AE, FMF, and SSA) show lower correlation with AERONET than AOD, but still show some skills for qualitative use.

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MODIS 3 km aerosol product: applications over land in an urban/suburban region

Cited by 156 publications

References 38 publications

MODIS 3 km aerosol product: algorithm and global perspective

MODIS 3 km aerosol product: algorithm and global perspective

A surface reflectance scheme for retrieving aerosol optical depth over urban surfaces in MODIS Dark Target retrieval algorithm

GOCI Yonsei Aerosol Retrieval (YAER) algorithm and validation during the DRAGON-NE Asia 2012 campaign

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