Fine-scale kinematic structure of a gravity wave within a midlatitude cyclone

On 11 February 2009 a mesoscale gravity wave of about 4 mb amplitude was observed by the Mobile Integrated Profiling System (MIPS) and the Mobile Alabama X-band dual polarization radar during the pilot phase of the Profiling of Winter Storms (PlOWS) field campaign. This gravity wave was sampled at the leading edge of a warm frontal rainband within an intensifying midlatitude cyclone over northern Illinois. The MIPS 915 MHz wind profiler observations revealed a high amplitude vertical motion couplet (3 m/s downdraft followed by a 3 m/s updraft) centered near 1.6 km AGL within a deep warm frontal inversion layer. A second gravity wave event occurred nine hours later beneath the dry slot of the cyclone.

This paper will present kinematic analyses of these two events based on single Doppler VAD analyses, dual Doppler radar analyses using a 30 km baseline between the MAX and KLOT WSR-88D radars, and 915 MHz wind profiler observations. One goal is to assess the relative accuracy of the dual Doppler wind retrievals within this environment. A second goal is to improve our understanding of the gravity wave kinematic fields. The kinematic fields will be combined with the thermodynamic structure of the environment around the gravity waves using the MIPS microwave profiling radiometer (1-min temporal resolution) and 2-h soundings that were launched 10 km from the co-located MIPS/MAX site.