Aerosol satellite remote sensing

Abstract

Aerosols are inportant for many processes in the atmosphere. Aerosols are a leading uncertainty in predicting global climate change, To a large extent this uncertainty is caused by a lack of knowledge on the occurrence and concentration of aerosols. On global scale, this information can only be obtained by satellite remote sensing.

In this thesis three techniques satellite remote sensing are presented. One of these applies only over the ocean, the other two were primarily designed for use over land. These methods compute the spectral aerosol optical depth, which is the column integrated aerosol extinction coefficient along a vertical path through the atmosphere.

The different retrieval methods were applied to data from the Along Track Scanning Radiometer 2 (ATSR-2), the Advanced Very High Resolution Radiometer (AVHRR) and the Global Ozone Monitoring Experiment (GOME). Comparisons with ground based and airbornemeasurements showed that the aerosol optical depth and its spectral behavior can accurately be determined using satellite remote sensing methods. Frequently, very high spatial gradients in the aerosol optical depth, typically a factor of two or three over less than a hundred kilomneters were observed.

The aerosol optical depth determined using satellite remote sensing was compared to results from a chemical transport model. These comparisons show reasonable agreement, particularly in regard of the large assumptions in the method to derive the aerosol optical depth from the model results.