Ray Tracing of Gravity Waves as a Possible Warning System for Tornadic Storms and Hurricanes

Abstract

Gravity waves with wave periods of 13 to 15 min and horizontal phase velocities of 90 to 220 m s?1 were present in ground-based observations of the upper atmosphere during time periods when tornadoes were occurring and gravity waves with wave periods of 20 to 25 min and horizontal phase velocities of 100 to 200 m s?1 were detected when a hurricane was present. Combinations of available neutral atmosphere data and model parameter values were used with a group ray tracing technique in an attempt to locate the sources of these waves. Computed sources of the waves with periods of 13 to 15 min were located within 50 km of the locations where tornadoes touched down from 2 to 4 h later. In the case of the waves with periods of 20 to 25 min it was found that the computed location of the source was roughly where the hurricane would be located 3 h after the waves were excited. The applicability of the present study to a tornado and hurricane warning system is noted.