We used CalCOFI data to model the likelihood of capturing Pacific mackerel larvae as a function of water temperature, zooplankton displacement volume, geostrophic flow (i.
Mixed-layer depth was used as an indicator of stratification of the water column, and geostrophic flow as a measure of horizontal current strength, both of which also potentially affected production and food availability (Mantyla et al.
The index of geostrophic flow was calculated on the basis of a fitted surface in dynamic height for each year, which was estimated by a method similar to that used to fit digital elevation maps to terrestrial slope data.
The final logistic model indicated that presence of Pacific mackerel larvae could be predicted on the basis of zooplankton displacement volume, geostrophic flow, the CPFV index, the interaction between latitude and day of year, and the interaction between latitude and water temperature (Table 1).
This outcome was due to the effect of temperature offset by reduced geostrophic flow and zooplankton abundance.
The model indicated that distributions of Pacific mackerel larvae could be predicted by using zooplankton displacement volume, geostrophic flow, and temperature as predictors of physical habitat in the California Current system.
This information becomes especially vital in Estonian nearshore waters where a complex interplay of the large-scale air flow with surface roughness and the presence of large-scale features such as the North Estonian klint cause substantial in homogeneity of average wind properties in different coastal areas [1,2], and where the mismatch of the orientation of coastline and the dominant direction of the geostrophic flow
give rise to specific phenomena such as low-level jets along the coastline  (strong, apparently channelled easterly winds along the central part of the Gulf of Finland during certain seasons), or mismatch between directions of the most frequent and strongest winds .
Such boundary layers, or similar ones, are required to connect principally geostrophic flow
in the interior of the fluid to horizontal boundaries where conditions like a prescribed horizontal stress, or no-slip on a solid bottom, are given.
A likely explanation of the goodness of the Princeton Ocean Model in the present application is that the circulation is governed by the pressure gradient and the Coriolis acceleration for which the model provides a very good representation although the [sigma]-coordinates may cause a small erroneous component on geostrophic flows
due to numerical truncation error in the calculation of the pressure gradient (Mellor et al.