Radar Observations of Land Breeze Fronts

Abstract

In August 1969, the ultra-sensitive 10.7-cm wavelength JAFNA radar at Wallops Island, Va., recorded what was apparently a land breeze front 12–14 n mi off the coast. Accompanying meteorological data show the land breeze at the shore to be a layer of cold air less than 300 ft deep moving seaward at approximately 2 kt. The radar observations show the land breeze vertical frontal surface sloping landward at ∼20°, with convection over the warm water increasing the layer thickness to 2000 ft near the frontal zone. The radar-observed horizontal frontal surface is a sharp scalloped line echo in the lower 1000 ft but becomes diffuse above. As the local circulation during daylight hours changes to a sea breeze, the land breeze front recedes toward land and dissipates.