Evaluation of MODIS aerosol optical thickness over Europe using sun photometer observations

Schaap, Martijn; Timmermans, R. M. A.; Koelemeijer, R.; Leeuw, G. de; Builtjes, P. J. H.

doi:10.1016/j.atmosenv.2007.11.044

Cited by 41 publications

(23 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The algorithms underlying the collection 5 data have changed drastically, causing lower AOD to be retrieved in mid-latitudes, especially during summer (Levy et al, 2007a). For stations in the Netherlands and Belgium the collection 4 data showed a positive bias of 50% (Schaap et al, 2008). For collection 5 at Cabauw we find an average bias of −25%.…”

Section: Aod-pm 25 Relationshipmentioning

confidence: 67%

Exploring the relation between aerosol optical depth and PM2.5 at Cabauw, the Netherlands

Schaap¹,

Apituley

Timmermans³

et al. 2009

Atmos. Chem. Phys.

Self Cite

219

View full text Add to dashboard Cite

Abstract. Estimates of PM 2.5 distributions based on satellite data depend critically on an established relation between AOD and ground level PM 2.5 . In this study we performed an experiment at Cabauw to establish a relation between AOD and PM 2.5 for the Netherlands. A first inspection of the AERONET L1.5 AOD and PM 2.5 data showed a low correlation between the two properties. The AERONET L1.5 showed relatively many observations of high AOD values paired to low PM 2.5 values, which hinted cloud contamination. Various methods were used to detect cloud contamination in the AERONET data to substantiate this hypothesis. A cloud screening method based on backscatter LIDAR observations was chosen to detect cloud contaminated observations in the AERONET L1.5 AOD. A later evaluation of AERONET L2.0 showed that the most data that are excluded in the update from L1.5 to L2.0 were also excluded by our cloud screening, which provides confidence in both our cloud-screening method as well as the final screening in the AERONET procedure. The use of LIDAR measurements in conjunction with the CIMEL AOD data is regarded highly beneficial. Contra-intuitively, the AOD to PM 2.5 relationship was shown to be insensitive to inclusion of the mixed layer height. The robustness of the relation improves dependent on the time window during the day towards noon. The final relation found for Cabauw is PM 2.5 =124.5×AOD−0.34 and is valid for fair weather conditions. The relationship found between bias corrected MODIS AOD and PM 2.5 at Cabauw is very similar to the analysis based on the much larger datasetCorrespondence to: M. Schaap (martijn.schaap@tno.nl) from ground based data only. We applied the relationship to a MODIS composite map to assess the PM 2.5 distribution over the Netherlands for the first time. The verification of the derived map is difficult because ground level artefact free PM 2.5 data are lacking. The validity and utility of our proposed mapping methodology should be further investigated.

show abstract

Section: Aod-pm 25 Relationshipmentioning

confidence: 67%

Exploring the relation between aerosol optical depth and PM2.5 at Cabauw, the Netherlands

Schaap¹,

Apituley

Timmermans³

et al. 2009

Atmos. Chem. Phys.

Self Cite

219

View full text Add to dashboard Cite

show abstract

“…Irie et al, 2012), whereas AERONET is widely used to validate satellite-derived aerosol optical depth (e.g. Schaap et al, 2008). The comparison between FTIR and IASI NH 3 column reported here can be seen as a first step in the validation of NH 3 satellite products.…”

Section: Discussionmentioning

confidence: 99%

An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements

et al. 2016

View full text Add to dashboard Cite

Abstract. Global distributions of atmospheric ammonia (NH 3 ) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH 3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH 3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH 3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH 3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatiotemporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH 3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH 3 levels, whereas correlations are lower at sites with low atmospheric NH 3 levels close to the detection limit of the IASI instrument. A combination of the observations Published by Copernicus Publications on behalf of the European Geosciences Union. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (−50 to +100 %).

show abstract

“…Only when > 12 pixels are classified as cloud free, retrieval is attempted. The AOD is retrieved over surfaces that are not highly reflective (hence snow or ice covered surfaces and desserts are excluded) (Schaap et al, 2008). The algorithms are described by Kaufman and Tanre (1998), and updates are discussed by Remer et al (2005).…”

Section: Instrumentation and Datamentioning

confidence: 99%

Variability of Aerosol Parameters Derived from Ground and Satellite Measurements over Varanasi Located in the Indo-Gangetic Basin

Tiwari

2013

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

Atmospheric aerosol plays a very important role in the Earth's radiation budget and global climate studies. This study reports the variability of the physical and optical properties of columnar aerosol and water vapour over Varanasi (25.2°N, 82.9°E), located in the heart of the Indo-Gangetic Basin, for the first time. The study was carried out using a MICROTOPS-II sunphotometer to measure the Aerosol Optical Depth (AOD) and metrological parameters. It is observed that the AOD loading is enhanced during the pre-monsoon and winter seasons, while it is decreased during the monsoon season. The variability of the angstrom coefficient (α) and turbidity coefficient (β) shows that in the pre-monsoon season coarse-mode aerosol particles are dominant, while fine-mode aerosol particles are dominant in the winter. We compared our MICROTOPS-II ground-based data with the level-3 data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra satellite. A good seasonal correlation (correlation coefficient, R 2 ~0.57) was observed between MICROTOPS-II and MODIS AOD data. The results of the variability of water vapor over Varanasi are also discussed. The correlation coefficient (R 2 ) between daily MICROTOPS-II and MODIS water vapor is found to be more than 0.85 for the year 2011.

show abstract

Evaluation of MODIS aerosol optical thickness over Europe using sun photometer observations

Cited by 41 publications

References 33 publications

Exploring the relation between aerosol optical depth and PM<sub>2.5</sub> at Cabauw, the Netherlands

Exploring the relation between aerosol optical depth and PM<sub>2.5</sub> at Cabauw, the Netherlands

An evaluation of IASI-NH<sub>3</sub> with ground-based Fourier transform infrared spectroscopy measurements

Variability of Aerosol Parameters Derived from Ground and Satellite Measurements over Varanasi Located in the Indo-Gangetic Basin

Contact Info

Product

Resources

About

Evaluation of MODIS aerosol optical thickness over Europe using sun photometer observations

Cited by 41 publications

References 33 publications

Exploring the relation between aerosol optical depth and PM&lt;sub&gt;2.5&lt;/sub&gt; at Cabauw, the Netherlands

Exploring the relation between aerosol optical depth and PM&lt;sub&gt;2.5&lt;/sub&gt; at Cabauw, the Netherlands

An evaluation of IASI-NH&lt;sub&gt;3&lt;/sub&gt; with ground-based Fourier transform infrared spectroscopy measurements

Variability of Aerosol Parameters Derived from Ground and Satellite Measurements over Varanasi Located in the Indo-Gangetic Basin

Contact Info

Product

Resources

About

Exploring the relation between aerosol optical depth and PM<sub>2.5</sub> at Cabauw, the Netherlands

Exploring the relation between aerosol optical depth and PM<sub>2.5</sub> at Cabauw, the Netherlands

An evaluation of IASI-NH<sub>3</sub> with ground-based Fourier transform infrared spectroscopy measurements