Comparison of ensemble-based and variational-based
data assimilation schemes in a Quasi-Geostrophic model.
Shu-Chih Yang et al.
3D-Var
Hybrid (3DVar+20 BVs)
12-hour 4D-Var
LETKF (40 ensemble)
24-hour 4D-Var
2.4
1.9
1.0
0.3
2.5
1.8
1.5
0.15
Time
(minutes)
0.44
0.44
0.48
0.67
0.35
0.56
0.70
1.44
RMS error
(
«
10
-2
)
l
=9
l
=7
l
=5
l
=3
24 hr
12hr
LETKF
4D-Var
HYBD
3D-Var