VHF profiler observations of the troposphere obtained over a flat desert in northern Per¿ show the presence of strong, quasi-sinusoidal oscillations in the vertical wind velocity with periods of around 8--18 minutes. These oscillations are a very consistent feature of the vertical velocities over Piura, and are also observed at other profiler locations. This paper presents an overview of the wave characteristics obtained at Piura until this point, including results obtained using a second antenna built a few hundreds meters to the west of the main antenna to measure horizontal wavelengths and phase velocities. Briefly, the Piura waves appear to have horizontal wavelengths in the zonal direction of 5--10 m, with either westward or eastward phase velocities (in a ground-based reference frame) of 5--15 m s-1. Their occurrence appears to be causally related to the magnitude of the easterly wind, which blows over the Andean Cordillera some 60 km to the east of the site.¿ 1997 American Geophysical Union