KMA reanalysis wind data accuracy disputed in audit
Korea Meteorological Administration's (KMA) 'reanalysis wind field' data, now usable for onshore wind permits since October 2026, faces accuracy disputes. Lawmaker Kim Tae-seon claims KMA's reported 0.46 m/s wind speed error is misleading, citing an independent check showing a 2.57 m/s error, five times higher. KMA acknowledged the limitation and promised independent verification.
Our take
Is Korea's government reanalysis wind data reliable enough to replace on-site measurement for onshore wind projects?
Korea's government reanalysis wind data can replace on-site measurement in onshore wind licence applications but is not yet reliable enough to size a project, as no independent accuracy check exists.
The published error was checked against the same observations used to build the data, so it measures fit rather than accuracy at an unmeasured site. The verdict changes only with the independent evaluation the agency has promised, for which no date or method has been published.
What the source says
- Starting October 2026, the reanalysis wind field data can replace the previously required 1 year or more of actual wind measurement data for onshore wind power project permit applications.
- Kim Tae-seon Lawmaker Kim Tae-seon pointed out that KMA promoted its reanalysis wind field's wind speed error of 0.46 m/s as being about one-fifth of Europe's ERA5 (2.52 m/s) and America's MERRA-2 (2.41 m/s).
- Kim Tae-seon Kim Tae-seon stated that KMA used the same 12 observation points for accuracy assessment that were used to produce the reanalysis wind field data.
- Kim Tae-seon Kim Tae-seon argued that KMA's evaluation method was like 'giving the answer key before the test' because the same observation values were reflected in data production and then used for accuracy evaluation.
- KMA explained that its existing evaluation method is a necessary process to confirm the degree of observation value reflection and analysis quality.
- Lee Mi-seon KMA Director Lee Mi-seon stated that due to a lack of separate budget and personnel for developing high-resolution reanalysis wind fields, there is insufficient independent observation data for verification.
- KMA provides 5 years of wind information at 1km intervals and 10-minute units starting from 2026.
- Lee Mi-seon KMA Director Lee Mi-seon agreed that evaluating differences between existing observation data and analysis results needs to be distinguished from independent accuracy verification.
- Lee Mi-seon KMA Director Lee Mi-seon promised to conduct an independent data evaluation and report the results to lawmaker Kim Tae-seon's office.
For investors — Onshore wind developers should use the reanalysis data for the licence application but keep on-site measurement for the energy yield estimate until the independent evaluation is out.
Lenders to onshore wind projects should check whether a financing case rests on reanalysis data alone and, where it does, ask for site measurement or an independent yield assessment.
Watch: KMA's report on independent verification of reanalysis wind field accuracy to the National Assembly.
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