HIERARCHAL INDUCTIVE PROCESS MODELING AND ANALYSIS ...

his research on the Ross Sea Phytoplankton dynamic, Borrett (unpublished data)
worked with real-life measurements for Phytoplankton and Nitrate and inputted this
data into HIPM, for that particular reason I decided to look at experiment number 8
which assumed data for both Nitrate and Phytoplankton (cf. Table 4). The number
of good fit models, under a .5 reMSE, produced by HIPM is 25. When observations
for Zooplankton are added no models under the chosen reMSE cutoff are selected; on
the other hand when Iron or Detritus are added a significant decrease in the number
of good fit models can be observed. The addition of detritus (experiment 19) and
iron (experiment 21) yielded respectively 13 and 15 good fit models. However, out
of all the models selected in experiment 8 only 2 models were part of the set selected
in experiment 19 (addition of detritus data) and 3 models from the set selected
in experiment 21 (addition of iron data). A comparison of the structures of these
models (the models can be found in appendix D and E) that they differ only, by
the type of Zooplankton grazing process used, by the parameter values and, in some
cases, by the Phytoplankton growth limitation (aka M(t)). Otherwise the structures
of these models are comparable, implying perhaps that the grazing processes used
in these models have similar effects on the ecosystem, which is plausible given the
number of grazing processes present in the process library. It is in fact this high
number of grazing options that makes for a very large structural search space.
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