A CASE-STUDY OF MOUNTAIN LEE WAVE EVENT OF JANUARY 6, 1992

A mountain wave event, observed at the southern tip of Greenland on January 6, 1992, was corroborated by three experiments: the Meteorological Measurement System (MMS), the Microwave Temperature Profiler (MTP), and the Reactive Nitrogen Instrument (NO/NO(y)). Gravity wave signatures with classical phase relationship between wind and temperature were observed on both the outbound and inbound legs at different altitudes. The waves showed both vertically propagating and evanescent properties. Characteristics of the dominant wave mode are: wavelength almost-equal-to 35 km; vertical displacement almost-equal-to 0.8 km, and peak-to-peak vertical wind almost-equal-to 6 ms-1. With the prevailing wind at almost-equal-to 37 ms-1, the stratospheric temperature was reduced by 6K to 195.5K within 8 minutes. The implication and potential impact of mountain lee waves on the formation of polar stratospheric clouds (PSC's) are discussed.