For more than 70 years measurements of the global and diffuse solar surface radiation have been taken within the DWD measurement network. Since 2006 those two radiation quantities are recorded with a temporal resolution of 1 minute at currently more than 30 stations.
At Meteorological Observatory in Lindenberg, we developed a new optimal estimation-based retrieval algorithm to estimate the AOD from ground-based global and diffuse broadband radiation measurements, measurements of the total column water vapor from GNNS, and ozone from the satellite-borne instrument OMI. The suitability of using the global surface radiation as a source to estimate the Aerosol Optical Depth (AOD) at certain wavelength based on radiative transfer simulations was already shown in several studies. Adding the information on the diffuse surface radiation increases the information content on the aerosol size distribution. Thereby we could reduce the error between the AOD derived from broadband measurements and the AOD derived from photometric measurements. Comparisons of the derived AOD with 7 collocated AERONET sites in Germany show a very good agreement with a monthly mean difference below 0.02 in the AOD. The differences in the AODs can be simply described by the differences in observed airmass and larger measurement errors of the broadband observations.
With the radiative transfer model, used in the retrieval algorithm as a forward model, we calculate for each measurement the incoming surface radiation for a cloud and aerosol-free atmosphere to estimate the direct aerosol effect for the daily mean AOD. For this reason, the estimated direct aerosol effect is limited to days with at least 10 minutes of cloud-free observations.
In our presentation, we will show validation results of the algorithm as well as trend analysis of the AOD and direct aerosol effect in Germany at available pyranometer sites since 2006.
How to cite: Filipitsch, F., Doppler, L., Seifert, A., and Wacker, S.: Estimation of the spectral aerosol optical depth from broadband surface radiation measurements and quantification of the direct aerosol effect in Germany, EMS Annual Meeting 2022, Bonn, Germany, 5–9 Sep 2022, EMS2022-546, https://doi.org/10.5194/ems2022-546, 2022.
