Cloud Conditions Favoring Secondary Ice Particles in Tropical Maritime Convection

Progress in understanding the formation of ice in lower tropospheric clouds is quite slow because of the difficulties in characterizing the many complex interactions that lead to ice initiation, and the dynamic, non-steady state nature of the clouds. Our study characterizes the conditions where secondary ice particles—specifically identified as needle or thin columnar types, are observed in tropical maritime convection during the Ice in Clouds Experiment-Tropical (ICE-T), based out of St. Croix, V. I., and the NASA AMMA experiment (NAMMA) in 2006 sampling from Cape Verde, Africa. We characterize the liquid and ice microphysics as a function of temperature and vertical velocity where secondary ice is likely to be generated.mWe will elucidate a process that we think is a copious secondary ice particle generator. Our hope is that our studies lead to a better understanding of how secondary ice production proceeds in natural clouds, and that it can lead to more realistic laboratory studies to study the processes involved.