SEVIRI AOD retrieval

The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit detected radiances (temporal resolution 15 min and spatial resolution 3 km in nadir) give a good opportunity to monitor aerosols above Europe.

The objective of this work is to further develop techniques and algorithms for NRT retrieval of the aerosol optical depth (AOD) from the SEVIRI data over the territory of Poland, Romania, Czech Republic and, if feasible, southern Norway and Sweden (up to 63 -64°N). Zawadzka and Markowicz [2014] proposed a technique for deriving AOD from SEVIRI. AOD will be derived based on optimal interpolation approach for a synergistic use of satellite and ground-based observations and aerosol transport model output, such us  Copernicus Atmospheric Monitoring Services (CAMS). The algorithm will implemented for the now-casting in the SAMIRA target areas.

An example of SEVIRI aerosol optical depth obtained over Poland is shown below. Fig. 1 shows AOD at 635 nm calculated for 15 min at 7:00, 8:00 and 9:00 UTC (in columns) on 11-14 and 16 September 2016 (in rows); white pixels are due to clouds. Aerosol variability for each consecutive hour do not vary much. The data are indicating high aerosol load (AOD >0.3) on 11-13 September over the country. The strongest spatial variability of AOD is captured on 14 September, with sharp edge of AOD stretched approximately 100km off and along the West and South border of Poland, what can be attributed to the dynamic air-clearing process (fast transport of the Arctic air-mass).

Aerosol optical depth obtained over Poland from SEVIRI sensor at 635 nm calculated for 15 min at 7:00, 8:00 and 9:00 UTC (in columns) on 11-14 and 16 September 2016 (in rows); white pixels are due to clouds.
Fig. 1: Aerosol optical depth obtained over Poland from SEVIRI sensor at
635 nm calculated for 15 min at 7:00, 8:00 and 9:00 UTC (in columns) on

The SEVIRI AOD maps (Fig. 1) well resemble the CAMS AOD maps, shown in Fig. 2, except for the 16 September, where CAMS clearly underestimates the AOD values and spatial variability.

Fig. 2: Aerosol optical depth at 550nm forecast by CAMS at 6:00 UTC on 11-16 September 2016, from upper left following rows (data source: http://atmosphere.copernicus.eu).
Fig. 2: Aerosol optical depth at 550nm forecast by CAMS at 6:00 UTC on
11-16 September 2016, from upper left following rows (data source:
http://atmosphere.copernicus.eu).

References:

Zawadzka, O., and K. Markowicz (2014), Retrieval of Aerosol Optical Depth from
Optimal Interpolation Approach Applied to SEVIRI Data, Remote Sens., 6(8),
7182–7211, doi:10.3390/rs6087182.