EVOLUTION OF THE MONTEREY BAY SEA-BREEZE LAYER AS OBSERVED BY PULSED DOPPLER LIDAR

As Part of the Land/Sea Breeze Experiment (LASBEX) to study the sea br eeze at Monterey Bay, the pulsed Doppler lidar of the NOAA / ERL Wave Propagation Laboratory Performed vertical and nearly horizontal scans of the developing sea breeze on 12 days. Analyses of Doppler velocity data from these scans revealed details on the growth of the sea-breeze layer and on the horizontal variability of the sea breeze resulting f rom inland topography. Two days were selected for study when the ambie nt flow was offshore, because the onshore flow of the sea breeze was e asy to discern from the background flow. Sequences of vertical cross s ections taken perpendicular to the coast showed the beginnings of the sea breeze beneath the land breeze at the coast and the subsequent gro wth of the sea-breeze layer horizontally and vertically. On one of the days a transient precursor-a ''minor sea breeze''-appeared and disapp eared before the main sea breeze began in midmorning. Other issues tha t the lidar was well suited to study were the compensating return flow , the Coriolis effect, the effects of topography, and the growth of th e dimensions of the sea-breeze layer. No return flow above the sea bre eze and no Coriolis turning of the sea-breeze flow were found even thr ough the late afternoon hours. Terrain effects included an asymmetry i n the development of the sea breeze over water as opposed to over land and the persistence into the late morning hours of southeasterly flow from the Salinas River valley toward the vicinity of the lidar. Verti cal and horizontal dimensions of the sea-breeze layer were determined from lidar vertical cross sections. From these, length-to-width aspect ratios were calculated, which were then compared with aspect ratios d erived from recent analytical models. The theoretical values compared poorly with the observed values, most likely because the complicating effects of topography and stability were not accounted for in the theo retical models.