The data shown are from 5 different proprietary solar datasets created by Vaisala. All of the solar datasets are created using models to convert satellite imagery into irradiance estimates on the ground. The spatial resolution of the datasets is 2 arc minutes, or roughly 3km. They start between 1997 and 1999, depending on the region, and go through the most recent full month at an hourly temporal resolution.

The datasets use different algorithms to calculate irradiance from satellite imagery and take their inputs, such as aerosol optical depth, water vapor, etc., from different data sources. Each dataset has also been validated independently against ~200 ground stations for accuracy. To learn more about each dataset, see their FAQ entries: Vaisala 1.0, Vaisala 1.1 Vaisala 1.2, Vaisala 2.0, Vaisala 2.1

In the viewer, the long-term mean GHI values shown at the top cover the entire data period for each dataset. If a particular dataset is not available in a region it will say “unavailable”. The graph shows either the monthly or annual means for each dataset selected by the user. The graph can be modified to show only some datasets or a certain time period of particular interest.