On the maintenance of high tropical cirrus

Observations reveal that cirrus clouds are ubiquitous in the tropics and therefore significantly impact the radiation budget in this region. Here numerical studies are conducted using a two-dimensional cloud-resolving model with explicit microphysics to study the processes that lead to the maintenance of tropical cirrus. It is found that despite significant differences in the cloud dynamics among the simulations performed, the model is unable to maintain a cloud against the processes of sedimentation and evaporation under the assumed environmental conditions. It is hypothesized that a source of large-scale upward motion must be present to maintain tropical cirrus.