A network of three radar wind profiler-minisodar combinations located at the vertices of an approximately equilateral triangle 63 km on a side was estableshed as part of the Argonne Boundary Layer Experiments (ABLE) facility. Data from the network were used during and after the Cooperative Air Surface Exchange Studies (CASES) in April-May 1997 to calculate convergence within the mixed layer over the lower Walnut River watershed. The existence of the minisodar network colocated with the wind profilers creates a second, independent estimate of convergence that can be used to verify estimates derived from wind profiler data if the convergence is constant within the mixed layer. A 50-day period that includes the CASES97 study period is examined. Comparisons of vertical velocities calculated from convergence estimates within the mixed layer show good agreement between profiler and sodar when averaged over daytime hours; nighttime values are more difficult to evaluate because of local terrain effects and contamination of wind profiler data by migrating birds. Examples of episodic events such as frontal passages and nearby thunderstorms are discussed; they are found to cause large, short-term fluctuations in the convergence. The effects of local terrain on convergence calculations are also explored.