Fig. 4

Comparison between observation and simulation for ash fall and lapilli. a Without 4D-Var. b With 4D-Var. Small windows in both figures are enlargements of large regions (0–4000 g/m2)
Comparison between observation and simulation for ash fall and lapilli. a Without 4D-Var. b With 4D-Var. Small windows in both figures are enlargements of large regions (0–4000 g/m2)