Spatial evaluation of CAMS Radiation service using dense pyranometric networks

Kurzfassung

As part of the EU-funded CAMS (Copernicus Atmospheric Monitoring Services) project, the CAMS Radiation Service (CRS) provides estimates of direct and global downwelling solar irradiance (SSI). The SSI estimate uses ozone, water vapour and aerosols from CAMS and cloud properties assessed with the APOLLO_NG algorithm. In parallel to the continuous improvement of the SSI estimation method, the regular evaluation of solar radiation estimates is an important component of the CRS activities. CRS evaluation is generally carried out using high-quality three-component measurements as a reference. The advantage of such a station is that the maintenance and availability of the three components allow to reach a high level of confidence in the data. However, such stations are rare, which limits our understanding of the spatio-temporal error structure of CRS. In this work, we tested the use of a dense meteorological network of pyranometers as a complement to scientific radiation stations. Here, the potential of 1-minute SSI measurements from 250 stations operated by Météo-France for assessing CRS was tested based on 8 years of measurements.