Submesoscale vertical velocity is a key factor in ocean dynamics but challenging to measure and interpret due to its small magnitude, fine spatial and temporal scales and the variety of physical processes involved. The divergence of surface current was measured off Central California using airborne Doppler radar and surface wave imaging. Vertical velocity was computed as the surface divergence times depth. An upward-looking Doppler sonar on a neutrally buoyant float measured vertical velocity at 30 to 50 m depth, well below the mixed layer. The dominant signal was energetic near-N internal waves. Averaging over 2 km and 2-4 hours to suppress the waves, the two estimates of vertical velocity agreed to 0.3 mm/s rms with a few outliers; typical average values were 1 mm/s. This is unsettling given our decades-long focus on restratifying secondary circulations in the mixed layer as the most interesting and important causes of vertical velocity. Although the high correlation offers the prospect of satellite measurements of vertical velocity from surface divergence, this approach may recover only part of the total vertical motion, and perhaps not the part of most interest.