Why retain raw wind measurements after producing a cleaned dataset?

The short answer

Raw wind records should be retained because cleaning is an interpretation that may need review. A cleaned series is useful for analysis, but it should not erase the observations, original timestamps or information explaining why a value was changed or excluded. Keep source files and derived datasets separately identified.

Protect the original evidence

Archive the received files with their source, date, instrument configuration and file identity. Preserve missing-data codes and any provider quality flags. Avoid overwriting original values while fixing units, timestamps or invalid observations.

An unchanged raw archive is not automatically a trustworthy resource dataset. Its purpose is to retain evidence. Validity comes from documented checks and an analysis method that can be applied again.

Record each transformation

Maintain a processing log covering unit conversion, time alignment, quality exclusions, substitutions and aggregation. For each rule, identify the affected fields and periods. A versioned script or reproducible set of documented steps is more useful than an unexplained final spreadsheet.

Distinguish corrected observations from estimated replacements. For example, fixing a known unit label is different from filling an unmeasured hour using another source. Both can be legitimate, but they carry different evidence and uncertainty.

Use provenance to manage later decisions

When a resource estimate changes, compare data and processing versions before attributing the difference to new weather or turbine performance. The archive should reveal whether a revised filter, recovered file or updated assumption changed the result.

Provide a data dictionary, processing record and final analysis dataset in the assessment handover. This supports independent review and future extension of the campaign. It also allows a buyer to challenge a doubtful cleaning decision without losing the original measurements on which the project case was built.