Initial MST radar observations of upper tropospheric-lower stratospheric duct-like structures over Jicamarca, Peru

摘要

Persistent wind jet structures along zonal and meridional fields, believed tobe caused by stationary gravity waves, were detected in February 1999 inmesosphere-stratosphere-troposphere (MST) radar wind measurements of thetroposphere and lower stratosphere over Jicamarca, Peru. Over a continuousseven day span of MST-data analyzed in this study, two days of observationsshowed signatures of wave-like structures in the upper troposphere/lowerstratosphere wind jets associated with the phases of the stationary gravitywaves. We believe these wave-like structures are ducted gravity waves. Wepresent these initial observations, their characteristics, and the results ofsimple numerical simulations used in an attempt to mimic these observedfeatures. Although a fair replication of the observed ducted structure in thenumerical model is found, the observed period of ~90 min is nonethelessmuch longer than what is traditionally observed. As a result, the specificphysical nature of the observed structures is not fully established.Nevertheless, given the high quality of the observations, we demonstrate herethat continued analysis of this data set and concurrent modeling efforts willallow for a better understanding of Doppler ducts at high spatial andtemporal resolution, and the results presented here can ultimately be appliedto studies of middle atmospheric fronts, ducts, and bores.