Questions with get_contributions() and plots.contribution()

[dlamatta]

I’ve read through the documentation and the source code of Pastas, and I understand that the 'rise' values (when you plot the contributions with plots.contribution(name='stress_name') or get the contribution series with get_contributions()) represent the impact of each stress factor on the groundwater head. My question is whether this means that the simulated head value on day X is always equal to the simulated head value on day X-1, plus the sum of all the 'rise' values from day X-1?

Would you be able to assist me?

Thank you very much for your help.

[dbrakenhoff]

The simulated head is equal to the sum of all contributions + the constant:

sim = contrib_0 + contrib_1 + ... + contrib_n + constant_d

The observed head is equal to:

obs = sim + residuals

The head from the previous day is not used unless you put that into the model somehow.

[dlamatta]

Thanks so much for your insightful reply Davíd – I really appreciate your help!