Onlangs kwam ik dit tegen (het is van in 2009 dus ik weet niet of er al wat veranderd is). Iemand die er meer over weet? De conclusie is hier volgens mij dat de data waarmee het GFS model begint te rekenen niet goed, volledig, optimaal,... zijn?
"Is the GFS model really worse than the ECMWF?" OK, I went there. Forecasters amateur and professional have long-claimed the U.S. GFS model was more inaccurate than the ECWMF. The graph above proves it, and it is the basis for the business model of the ECWMF's institution, which sells the data at exorbitant prices (the GFS data is free -- a quarter of a million dollars will buy you the rights to use redistribute the ECMWF 25-day forecast, but not their weekly or monthly forecasts which go as far as a year out). Although that makes for a compelling reason to keep their secrets to themselves, they have recently started working with the U.S. government to help determine what's wrong with the GFS.
Last month, a breakthrough was discovered: When the GFS is run with the ECWMF Initialization data (see above), the accuracy improves dramatically (you can read the AMS presentation here). Unfortunately, implementing that is not as easy as you'd think - outside of the cost of using the ECWMF data, it only runs twice a day, so the GFS would no longer be able to run at 06Z & 18Z (midnight & noon). I suppose one other option is that we fix our initialization data, but I haven't heard much about that option taking shape. It would probably be a big undertaking. In any case, I'm thrilled that we now know what's wrong with the GFS.
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