PowerPoint Presentation - COMPARISON OF ENSEMBLE-BASED AND VARIATIONAL-BASED DATA ASSIMILATION SCHEMES IN A QUASI-GEOSTROPHIC MODEL

OBSERVATIONS

• Generated from the ‘truth’ plus “random errors” with error standard deviations of 1 m/s (u), 1 m/s(v), 1K(T), 10-4 kg/kg (q) and 100Pa(Ps).

• Dense observation network: 1 every 2 grid points in x and y direction

Tests within LETKF with SPEEDY

EXPERIMENTAL SETUP

• Run SPEEDY with LETKF for two months ( January and February 1982) , starting from wrong (doubled) observational errors of 2 m/s (u), 2 m/s(v), 2K(T), 2*10-4 kg/kg (q) and 200Pa(Ps).

• Estimate and correct the observational errors and inflation adaptively.