Spatial Organisation Affects the Pathway to Precipitation in Simulated Trade‐Wind Convection

• Published in: Geophysical Research Letters
• Main Authors: Jule Radtke, Raphaela Vogel, Felix Ament, Ann Kristin Naumann
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: precipitating shallow convection; convective organization; large‐eddy simulations; trade‐wind cumuli; Geophysics. Cosmic physics; QC801-809; North Atlantic
• Online Access: https://doi.org/10.1029/2023GL103579; https://doaj.org/article/495586ba746d497eb5bf6bc2497ed11b

Abstract We investigate whether and how spatial organization affects the pathway to precipitation in large‐domain hectometer simulations of the North Atlantic trades. We decompose the development of surface precipitation (P) in warm shallow trade cumulus into a formation phase, where cloud condensate is converted into rain, and a sedimentation phase, where rain falls toward the ground while some of it evaporates. With strengthened organization, rain forms in weaker updrafts from smaller cloud droplets so that cloud condensate is less efficiently converted into rain. At the same time, organization creates a locally moister environment and modulates the microphysical conversion processes that determine the raindrops' size. This reduces evaporation and more of the formed rain reaches the ground. Organization thus affects how the two phases contribute to P, but only weakly affects the total precipitation efficiency. We conclude that the pathway to precipitation differs with organization and suggest that organization buffers rain development.