Observational Case Studies and Diagnostic Analyses of Long-Lived Large- Amplitude Inertia-Gravity Waves
Technical rept. 15 Oct 1992-14 Oct 1993
STATE UNIV OF NEW YORK AT ALBANY RESEARCH FOUNDATION
Pagination or Media Count:
Effort for the first year has concentrated on 1 Preparing a gravity wave climatology 2 Documenting a long-lived large-amplitude wake low trough event on 16-17 November 1987 and 3 Analyzing the large-amplitude gravity wave present in the notable Midwest cyclone of 15 December 1987. The gravity wave climatology is based on hourly surface observations spanning a 10 - 15 year period at approximately 100 stations distributed fairly evenly across the United States. Preliminary results 7 stations suggest that large-amplitude gravity wave events occur at a frequency of one or two times per year at a given station. It is hypothesized that the more complete wave-event climatology to be derived in the second year will show regional variations understandable in terms of characteristic synoptic-scale signatures conducive to wave genesis. In the 16-17 November 1987 wake low event, the wake trough remains confined to the back edge of the precipitation shield associated with a major mesoscale convective system over the lower Mississippi Valley. The approach of the wake trough is marked by the cessation of precipitation and the onset of gusty easterly winds, consistent with simple gravity wave theory. Finally, in the 15 December 1987 Midwest gravity wave event, present research is focused on the initiation of the wave event preliminary results suggest that frontogenetical forcing may be contributing to wave generation.