Observations of the Marine Boundary Layer Thermal Structure over the Gulf Stream during a Cold Air Outbreak

Abstract

Thermal structure of the marine boundary layer (MBL) was studied during a five-day cruise over the coastal Atlantic Ocean off North Carolina. Three different synoptic conditions were present: ahead of a low moving along the coast, in the area of a frontal zone and during a cold air outbreak. The marine boundary layer height was deeper (approximately 1500 m) and more sharply defined during the cold air outbreak than when the flow was southwesterly with a long fetch over water; the height was only about 1000 m for the latter case. Latent heat fluxes were significantly larger than sensible heat, but during the cold air outbreak, sensible heat fluxes increased appreciably.