Anvil Characteristics as Seen by C-POL during the Tropical Warm Pool International Cloud Experiment (TWP-ICE)

Abstract

The Tropical Pacific Warm Pool International Cloud Experiment (TWP-ICE) took place in Darwin, Australia, in early 2006. C-band radar data were used to characterize tropical anvil (i.e., thick, nonprecipitating cloud associated with deep convection) areal coverage, height, and thickness during the monthlong field campaign. The morphology, evolution, and longevity of the anvil were analyzed, as was the relationship of the anvil to the rest of the precipitating system. The anvil was separated into mixed (i.e., echo base below 6 km) and ice-only categories. The average areal coverage for each anvil type was between 4% and 5% of the radar grid. Ice anvil thickness averaged 2.8 km and mixed anvil thickness averaged 6.7 km. Areal peaks show that mixed anvil typically formed out of the stratiform rain region. Peak production in ice anvil usually followed the mixed anvil peak by 1?3 h. Anvil typically lasted 4?10 h after the initial convective rain area peak. TWP-ICE experienced three distinct regimes: an active monsoon, a dry monsoon, and a break period. During the experiment (except the active monsoon period) there was a strong negative correlation between ice anvil thickness and ice anvil height, a strong positive correlation between ice anvil area and thickness, and a greater variance in ice anvil bottom than ice anvil top. These results have important implications for understanding how anvil affects the tropical atmosphere.