Properties of the atmospheric boundary layer above a subtropical oceanic front.

Abstract

The marine atmospheric boundary layer (MABL) and synoptic-scale situation is described using rawinsonde and sea-surface temperature (SST) data collected during the 1986 Frontal Air-Sea Interaction Experiment (FASINEX). The data obtained from 14 February to 09 March 1986 are divided into eight consecutive three-day periods and analyzed. Significant changes in synoptic-scale features and flow patterns occurred during each three-day period due to movement of low pressure systems. MABL changes noted were due primarily to large scale convergence. Thirteen pairs of rawinsonde launches, seven from opposite sides of an oceanic front and six from the same side (five warm, one cold) are compared. The time difference between soundings in each pair did not exceed sixty minutes. Boundary layer height, mixed layer potential temperature and specific humidity differences between paired rawinsonde launches were larger when launches were from opposite sides of the oceanic front. A combination of both shipboard and aircraft data will be necessary to further describe the conditions of the MABL and synoptic-scale situation.