Results from a Two-Layer and a Reduced Gravity Model of the Alboran Sea; and Vertical Shear from Tops.

摘要

This study has attempted to simulate the statistics of temporal and geographical distribution of shear over the upper 400 m of the world's oceans. In particular we have examined a large area of the North Pacific over the six month period March through August of 1981. Forcing was provided by the prediction fields obtained from FNOC's hemispheric weather model. Model results have shown: Surface shear increases from late winter - early spring to summer; The region south-southwest of the Bering Sea develops into a region of very high surface shear in spring and summer; The depth to which shear extends is closely correlated to the mixed layer depth, thus in winter shear values are found at greater depths than in summer; Seasonal comparisons show that the magnitude of shear is larger in May than in November, but extends to greater depths in November than in May; Shear instability is strongly linked to the passage of atmospheric fronts. Regions of stability occur under high pressure systems and low winds; Very little convective instability exists during the six month period examined (Ri < 0).