dit schrijft het ECMWF er over in dit document:
https://confluence.ecmwf.int/display/FUG/Section+8.1.3.1+Clustering+-+Medium+range
Flow dependent skill
It has been found:
- BL leads to the least accuracy in the forecasts - from Day3 the blocking frequencies are systematically underestimated.
- AR also leads to reduced accuracy in the forecasts – tends to be too persistent and missing transitions to BL.
- Transitions to BL are not well predicted in general, and appear particularly difficult when initially the cross-Atlantic westerly jet is in the southern location (NAO-) or the northern location (AR).
- Persistence of BL tends to be underestimated.
- Maintenance and/or transitions to an enhanced zonal flow (NAO+) tends to be overestimated.
- The ensemble spread is a useful indicator of the forecast error.
- -NAO has a higher skill than other types – The spread of the forecasts initiated in -NAO is significantly smaller than for the forecasts initiated in the other regimes.
wel fijn even zo!
