Assessment of two aerosol optical thickness retrieval algorithms applied to MODIS Aqua and Terra measurements in Europe

Glantz, Paul; Tesche, Matthias

doi:10.5194/amt-5-1727-2012

Cited by 8 publications

(6 citation statements)

References 28 publications

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“…Our results show good agreement between AOD estimated from MODIS using the ocean algorithm and AOD retrieved from Sun photometer measurements and are in accordance with other validation studies [e.g., Ichoku et al ., 2002; Levy et al, ; Glantz and Tesche , ]. The best agreement is found for cases classified as originating from the North African sector, which presents large aerosol loads usually linked to the transport of desert mineral dust particles.…”

Section: Resultsmentioning

confidence: 96%

Aerosol transport over the western Mediterranean basin: Evidence of the contribution of fine particles to desert dust plumes over Alborán Island

et al. 2014

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Eight months (June 2011 to January 2012) of aerosol property data were obtained at the remote site of Alborán Island (35.95°N, 3.03°W) in the western Mediterranean basin. The aim of this work is to assess the aerosol properties according to air mass origin and transport over this remote station with a special focus on air mass transport from North Africa. For air masses coming from North Africa, different aerosol properties showed strong contributions from mineral dust lifted from desert areas. Nevertheless, during these desert dust intrusions, some atmospheric aerosol properties are clearly different from pure mineral dust particles. Thus, Angström exponent α(440-870) presents larger values than those reported for pure desert dust measured close to dust source regions. These results combine with α(440, 670) À α(670, 870) ≥ 0.1 and low single scattering albedo (ω(λ)) values, especially at the largest wavelengths. Most of the desert dust intrusions over Alborán can be described as a mixture of dust and anthropogenic particles. The analyses support that our results apply to North Africa desert dust air masses transported from different source areas. Therefore, our results indicate a significant contribution of fine absorbing particles during desert dust intrusions over Alborán arriving from different source regions. The aerosol optical depth data retrieved from Sun photometer measurements have been used to check Moderate Resolution Imaging Spectroradiometer retrievals, and they show reasonable agreement, especially for North African air masses.

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Section: Resultsmentioning

confidence: 96%

Aerosol transport over the western Mediterranean basin: Evidence of the contribution of fine particles to desert dust plumes over Alborán Island

et al. 2014

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“…Those sensors provide good AOT statistics due to their large swath widths of 2.801, 1.270, 1.150 and 2.330 km, respectively. This effort includes the validation of BEAR AOT against ground-based remote sensing (Glantz and Tesche, 2012) before it can be used in climate and air-quality studies. Table 5 shows that some years are associated with favourable conditions for spaceborne retrievals of aerosol mass.…”

Section: General Results and Conclusionmentioning

confidence: 99%

“…The latter two parameters weight outliers to a smaller degree than the RMSE and are therefore more suitable for the validation of satellite retrievals of atmospheric parameters. The AAD and AAD rel parameters are defined in Glantz and Tesche (2012). Table 3 presents a summary of the validation of MODIS against AERONET for different scenarios of pixel availability.…”

Section: Validation Of Modis Aotmentioning

confidence: 99%

Spaceborne observations of low surface aerosol concentrations in the Stockholm region

Tesche¹,

Glantz²,

Johansson

2016

Tellus B: Chemical and Physical Meteorology

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A B S T R A C TThis article investigates the feasibility of using spaceborne observations of aerosol optical thickness (AOT) derived with the Moderate Resolution Imaging Spectroradiometer (MODIS) for monitoring of fine particulate matter (PM2.5) in an environment of low aerosol loading. Previous studies of the AOT-to-PM2.5 relationship benefit from the large range of observed values. The Stockholm region features a comprehensive network of ground-based monitoring stations that generally show PM2.5 values B20 mg m (3 . MODIS AOT at 555 nm is usually B0.20 and in good agreement with ground-based sun photometer observations in this region. We use MODIS Collection 5 AOT data with a horizontal resolution of 10 km )10 km and ground-based in-situ PM2.5 observations to derive an AOT-to-PM2.5 relationship that can be used to estimate fields of PM2.5. This has been carried out with respect to the months from April to September of the period 2000Á2013. Relative average absolute deviations of 33Á55 % (mean of 45 %) are obtained between MODIS-retrieved and ground-based PM2.5. The root mean square error is 0.2159 mg m (3 between retrieved and measured PM2.5. From spaceborne lidar observations, it is found that elevated aerosol layers are generally sparse in the Stockholm region. This favours remote sensing of PM2.5 from space. The deviations found between measured and retrieved PM2.5 are mainly attributed to infrequent situations of inhomogeneous aerosol layering for which column-integrated observations cannot be connected to surface conditions. Using MODIS Collection 6 data with a resolution of 3 km)3 km in a case study actually gives far fewer results than the coarser Collection 5 product. This is explained by the complex geography of the Stockholm region with a coastline and an abundance of lakes, which seems to induce biases in the retrieval of AOT at higher spatial resolution.

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“…The confidence interval is set to 68% to maintain consistency with previous research (Immler et al 2010;Glantz and Tesche, 2012) where the retrieval uncertainty is set to the standard deviation of the selected parameter that conforms to a Gaussian distribution. In such case, a randomly selected parameter lies inside the region which centers at the mean value and extends on the left and right sides by the magnitude quantified by the uncertainty with a 68% probability.…”

Section: /2 τ -mentioning

confidence: 99%

Influences of cloud heterogeneity on cirrus optical properties retrieved from the visible and near-infrared channels of MODIS/SEVIRI for flat and optically thick cirrus clouds

Zhou¹,

Sun²,

Zhang³

et al. 2017

Journal of Quantitative Spectroscopy and Radiative Transfer

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1 The influences of three-dimensional radiative effects and horizontal heterogeneity effects on the retrieval of cloud optical thickness (COT) and effective diameter (De) for cirrus clouds are explored by the SHDOM radiative transfer model. The stochastic cirrus clouds are generated by the Cloudgen model based on the Atmospheric Radiation Measurement program data. Incorporating a new ice cloud spectral model, we evaluate the retrieval errors for two solar zenith angles (SZAs) (30° and 60°), four solar azimuth angles (0°, 45°, 90°, and 180°), and two sensor settings (Moderate Resolution Imaging Spectrometer (MODIS) onboard Aqua and Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard METEOSAT-8). The domain-averaged relative error of COT (μ) ranges from-24.1 % to-1.0 % (SZA = 30°) and from-11.6 % to 3.3 % (SZA = 60°), with the uncertainty within 7.5 % ~ 12.5 % (SZA = 30°) and 20.0 % ~ 27.5 % (SZA = 60°). For the SZA of 60° only, the relative error and uncertainty are parameterized by the retrieved COT by linear functions, providing bases to correct the retrieved COT and estimate their uncertainties. Besides, De is overestimated by 0.7 μm ~ 15.0 μm on the domain average, with the corresponding uncertainty within 6.7 μm ~ 26.5 μm. The retrieval errors show no discernible dependence on solar azimuth angle due to the flat tops and full coverage of the cirrus samples. The results are valid only for the two samples and for the specific spatial resolution of the radiative transfer simulations.

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Assessment of two aerosol optical thickness retrieval algorithms applied to MODIS Aqua and Terra measurements in Europe

Cited by 8 publications

References 28 publications

Aerosol transport over the western Mediterranean basin: Evidence of the contribution of fine particles to desert dust plumes over Alborán Island

Aerosol transport over the western Mediterranean basin: Evidence of the contribution of fine particles to desert dust plumes over Alborán Island

Spaceborne observations of low surface aerosol concentrations in the Stockholm region

Influences of cloud heterogeneity on cirrus optical properties retrieved from the visible and near-infrared channels of MODIS/SEVIRI for flat and optically thick cirrus clouds

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