Scattering ratios of the Pinatubo aerosol layer obtained by the ship-borne lidar of the Roscomhydromet of Russia on-board PROFESSOR ZUBOV are presented. During a campaign primarily in the low-latitude (8 ¿N--43 ¿N) Atlantic Ocean, 48 days of data were obtained within the 73 day period spanning 11-July and 21-September of 1991 [Avdyushin et al., 1992>. These data show the aerosol cloud to be primarily in the 16--27 km altitude region, with a high degree of variability in the vertical structure and in the longitudinal structure, and to a lesser degree, in the latitudinal structure. Scattering ratios of up to 50 were recorded in the multi-layered structure which was often observed. These are the first lidar observations showing a high degree of zonal variability of the vertical structure of the aerosol layer. We show the latitudinal range of the Pinatubo aerosol cloud in the northern hemisphere over a 2 month period and estimate the latitudinal dispersion rate for the months of the measurements to be approximately 5¿ latitude per month. A clear periodic variability was observed in the altitude structure during the entire data-set primarily within 8 ¿N--22 ¿N latitude and within the altitude region of the layer, from which a mean zonal wind profile was produced by a spectral analysis of the aerosol profiles. ¿ American Geophysical Union 1993