Vaisala produces five different satellite irradiance datasets using different combinations of clear-sky models and sources of aerosol and water vapor inputs, each with its own strengths and weaknesses. The details for each dataset are contained in their respective FAQ pages.

The changes made in the November 2019 update affect the aerosol information in each of the datasets. The three datasets using the “Modified Kasten” clear sky algorithm (datasets 1.0, 1.1, and 1.2) now ingest data from the latest MODIS aerosol products released by NASA, i.e., Collection 6.1 rather than Collection 5.1. Reference parameter values used to describe aerosol characteristics were updated in datasets using the “REST2” clear sky algorithm (datasets 2.0 and 2.1). These changes are intended to improve the representation of aerosols, which strongly affect the transmission of radiation through the clear atmosphere.

Validation results for the revised datasets are provided in an updated version of our validation white paper. The updated white paper, which includes further details about our methodology, is available here.