Implementation of the Hinssen-Knap algorithm for the calculation of sunshine duration

The implementation of the Hinssen-Knap linear algorithm (HK-algorithm) for the calculation of sunshine
duration is decided on by TOWon October 12th 2009. This implementation report proposes a three-step-
plan. Start with creating a (seperate) series of hourly sunshine duration based on the global radiation
(since 1992 or longer, more than 25 stations) with the HK-algorithm, secondly compare these series
to the Bergman-Slob/Monna (BSM) series and to the conclusions of Hinssen (2006) and Hinssen and
Knap (2007) and decide (when HK is acceptable) on replacing BSM by HK and in the end communicate
details to users.