WRF => 4DVAR WRFDA

[weatherc]

WRF-kartat ovat nyt 4DVAR WRFDA-karttoja jossa paikkansapitävyys pitäisi olla parempi

Lyhyesti sanottuna niin pohjalla häärää edelleen WRF mutta mukana on nyt analyysiä sekä se käyttää mm. SYNOP-dataa ennusteeseen. 

Samalla tippui resoluutio 12 km:iin mutta ainakin mutu on että siinä on paljon hienojakoisempaa dataa mitä 9km:ssä ikinä ollut

[weatherc]

Tuossa lyhyesti lontooksi mitä 4DVAR WRFDA on:

Data assimilation is the technique by which observations are combined with an NWP product (the first guess or background forecast) and their respective error statistics to provide an improved estimate (the analysis) of the atmospheric (or oceanic, Jovian, etc.) state. Variational (Var) data assimilation achieves this through the iterative minimization of a prescribed cost (or penalty) function. Differences between the analysis and observations/first guess are penalized (damped) according to their perceived error. The difference between three-dimensional (3D-Var) and four-dimensional (4D-Var) data assimilation is the use of a numerical forecast model in the latter.