how to determine the state perturbed noise value

[dingxinjun]

dear proffesor: why should we add noise to the sate in each time loop after resample,and how to determine the0.4* np.random.randn(Nx, Nm) the noise size

[ecosme38]

The particle filter selects the best ensemble members at each analysis step. To conserve ensemble size, some are duplicated. Adding noise makes them deviate from each other during forecast to gain spread. The noise amplitude is here determined empirically, after trials and errors.

[dingxinjun]

thanks for your reply