Three-Dimensional Air Trajectories Determined from Tetroon Flights in the Planetary Boundary Layer of the Los Angeles Basin

Abstract Between 9 September and 2 October 1969, 105 constant-volume balloons (tetroons) were released from various sites in the Los Angeles Basin for the purpose of obtaining three-dimensional air trajectories in the planetary boundary layer of the Basin. The tetroons, with transponders attached, were tracked by an M-33 radar positioned atop Mt. Thom, 5 km north of Glendale. In general, the tetroons at heights of a few hundred meters tended to move slowly westward between midnight and sunrise, slowly northward between sunrise and noon, and rapidly eastward between noon and sunset. Tetroons launched from Redondo Beach and the Long Beach area during the day distinctly show the convergence zone extending northeastward from the Palos Verdes Hills due to the confluence of sea breezes from the west and south. Tetroons released near the downtown area around sunrise tend to drift toward city center before moving northeastward into the Pasadena-Glendale area. During the day the tetroons oscillate through much of ...