Vertical velocity characteristics of deep convection over Darwin, Australia

Continuous vertical velocity measurements using a 50-MHz wind profiler loca ted at Darwin in northern Australia during periods of active convection hav e been analyzed. This dataset is dominated by continental-type convection. Numerous examples of shallow, deep, and decaying convection were seen and i t is shown that only the deep systems have substantial tilts to the draft s tructure. The most intense updrafts occur above the freezing level, but sha llow convection also produces large-amplitude vertical motions. The strengt h of these updrafts in this dataset is very similar to other tropical, ocea nic data. That observation is consistent with the idea that the magnitude o f the updrafts is much less in the Tropics than for intense midlatitude con vection because the convective available potential energy is distributed ov er a much deeper layer in the Tropics, although more intense updrafts may b e present at other tropical locations, such as the Tiwi Islands north of Da rwin. The size of the cores, however, is significantly greater here than wi th oceanic data and is similar to midlatitude results, thus supporting the suggestion that boundary layer depth is important in determining the horizo ntal scale. There is a net detrainment in the upward cores above the freezi ng level occurring at all space scales. The mass flux in intense updrafts i s almost constant with height below the freezing level but is almost cancel led by downdrafts and the immediate surrounding environment. Two population s of downdrafts are seen, one a dynamical response associated with intense updrafts at all heights and a second driven by precipitation processes belo w the freezing level. The core size, intensity, and mass flux are all appro ximately lognormally distributed. It is shown that a wide range of velocity and size scales contribute to the upward mass flux.