Relationships between large-scale motion and convective precipitation during GATE.

Abstract

Upper air and surface data from GATE are used to examine the interrelationships between convective-scale precipitation and the larger scale wind field. Time series of 12 h averages indicate that the precipitation events in Phase III corresponded very closely to the cyclonic maxima of the 700 mb relative vorticity, reflecting the influence of the easterly waves. During Phases I and II, when easterly waves were poorly organized, the precipitation events did not correspond closely to the cyclonic vorticity maxima. On the other hand, precipitation events showed good correspondence with the large-scale (A/B) 700 mb upward vertical velocity maxima and surface meridional convergence d v/d y during all three phases. This shows that the precipitation is clearly related to events on a larger scale.- from Authors