Validation of a modified AVHRR aerosol optical depth retrieval algorithm over Central Europe

Riffler, Michael; Popp, Christoph; Hauser, Adrian; Fontana, Fabio; Wunderle, Stefan (2010). Validation of a modified AVHRR aerosol optical depth retrieval algorithm over Central Europe. Atmospheric Measurement Techniques (AMT), 3(5), pp. 1255-1270. Göttingen: Copernicus Publications 10.5194/amt-3-1255-2010

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The Advanced Very High Resolution Radiometer (AVHRR) carried on board the National Oceanic and Atmospheric Administration (NOAA) and the Meteorological Operational Satellite (MetOp) polar orbiting satellites is the only instrument offering more than 25 years of satellite data to analyse aerosols on a daily basis. The present study assessed a modified AVHRR aerosol optical depth τa retrieval over land for Europe. The algorithm might also be applied to other parts of the world with similar surface characteristics like Europe, only the aerosol properties would have to be adapted to a new region. The initial approach used a relationship between Sun photometer measurements from the Aerosol Robotic Network (AERONET) and the satellite data to post-process the retrieved τa. Herein a quasi-stand-alone procedure, which is more suitable for the pre-AERONET era, is presented. In addition, the estimation of surface reflectance, the aerosol model, and other processing steps have been adapted. The method's cross-platform applicability was tested by validating τa from NOAA-17 and NOAA-18 AVHRR at 15 AERONET sites in Central Europe (40.5° N–50° N, 0° E–17° E) from August 2005 to December 2007. Furthermore, the accuracy of the AVHRR retrieval was related to products from two newer instruments, the Medium Resolution Imaging Spectrometer (MERIS) on board the Environmental Satellite (ENVISAT) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on board Aqua/Terra. Considering the linear correlation coefficient R, the AVHRR results were similar to those of MERIS with even lower root mean square error RMSE. Not surprisingly, MODIS, with its high spectral coverage, gave the highest R and lowest RMSE. Regarding monthly averaged τa, the results were ambiguous. Focusing on small-scale structures, R was reduced for all sensors, whereas the RMSE solely for MERIS substantially increased. Regarding larger areas like Central Europe, the error statistics were similar to the individual match-ups. This was mainly explained with sampling issues. With the successful validation of AVHRR we are now able to concentrate on our large data archive dating back to 1985. This is a unique opportunity for both climate and air pollution studies over land surfaces.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Remote Sensing
08 Faculty of Science > Institute of Geography

UniBE Contributor:

Riffler, Michael; Fontana, Fabio and Wunderle, Stefan

Subjects:

900 History > 910 Geography & travel

ISSN:

1867-1381

Publisher:

Copernicus Publications

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:20

Last Modified:

11 Sep 2015 15:57

Publisher DOI:

10.5194/amt-3-1255-2010

Web of Science ID:

000283661300006

BORIS DOI:

10.7892/boris.6489

URI:

https://boris.unibe.ch/id/eprint/6489 (FactScience: 211462)

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