A difficult problem when using HMMs is that of specifying
the model in the first place. There are two parts to solve this
problem; firstly the design of the structure i.e. what states there
are and how they are connected, and secondly the assignment
of parameter values, the transition and emission probabilities.
Number of states of (SPI) S1, S2, . . ., S7 from hydrological
point of view are defined as follows: State 1 – Extremely wet,