Closure mismatch during first half of 2018

The data until ~2018-06-15 rather suspicious. It looks potentially like soiling.

Both the DHI and GHI pyranometers were changed in June 2018. The DNI calibration coefficient was also updated in May 2018, but the coefficient hardly changed at all, so this is not the reason.


Start by reviewing the data around 2018-06-15 and the DHI/GHI pyranometer replacements and DNI calibration change described in the issue. Establish whether the closure mismatch is caused by soiling or instrumentation, then document the cause and any affected data once the investigation is complete.

Written by the indexing model from the issue text.