used for the starting value on year day 1. (e) P vs. E relation used in the model with
large initial slope.
(^) (After Frost 1993.)
(^) Frost (1993) captured most of this in a one-dimensional model, with that one
dimension being depth. It describes processes down the water column by installing
separate NPZ models in each of numerous layers, in this case an upper mixing layer
and a series of deeper layers through the progressive density stratification to the
bottom of the euphotic zone. Exchange between adjacent layers is included as a
process at each time step. Like the Evans–Parslow model already described,
phytoplankton growth depends upon irradiance (but here according to the Jassby &
Platt P vs. E function), modified somewhat when available fixed nitrogen
concentration is reduced. To model the subarctic Pacific, it is assumed that the
phytoplankton are very small, because big phytoplankton are strongly growth-limited
by low iron availability. Since the phytoplankton are small, the grazers are
characterized as protozoans with suitably high potential growth rates. The upper layer