Analysis of hydrographic data collected during 1977-1978 at six locations on southern Georges Bank revealed differences in the sinusoidally-modeled mean seasonal hydrographic cycles over short cross-bank spatial scales. In depths of less than 60 m, vertical stratification remained weak year-round, with no seasonal cycle. At greater depths, a transition to a stratified water column occurred from late spring to early autumn. However, statistically-significant differences exist between the mean hydrographic cycles derived from data collected in two contiguous seasonally-stratified zones located within the deeper region. In 60-80 m depths: (1) the mean cycle of the maximum density gradient in the seasonal pycnocline was dominated by a one cycle-per-year model; (2) the maximum density gradient varied by almost two orders of magnitude, from a January minimum to a late July maximum; and (3) the mean depth of the maximum density gradient remained near 20 m year-round. In 80-100 m depths: (1) the mean cycles of both the maximum density gradient and pycnocline depth were dominated by a one cycle-per-year model; (2) the maximum density gradient varied by only one order of magnitude; and (3) the mean depth of the maximum density gradient varied from 20 m in early June to 60 m in late December when the water column is well mixed. The cross-bank transition from well-mixed to seasonally-stratified waters agrees with the Simpson-Hunter stratification parameter computed by other workers for the study domain and, thus, to first order is consistent with existing one-dimensional models for tidally-mixed seas. Variations between hydrographic cycles noted within the seasonally-stratified waters may be due to the presence of the "cold-band" and on-bank advection of slope waters, thus modifying the one-dimensional assumptions.
