Moisture distributions in tropical cold pools
Submitter:
Zuidema, Paquita — University of Miami
Chandra, Arunchandra S. — University of Miami
Area of research:
Cloud Processes
Journal Reference:
Chandra A, P Zuidema, S Krueger, A Kochanski, S de Szoeke, and J Zhang. 2018. "Moisture distributions in tropical cold pools from equatorial Indian Ocean observations and cloud-resolving simulations." Journal of Geophysical Research: Atmospheres, 123(20), 10.1029/2018JD028634.
Science
Rain-driven downdraughts (cold pools) occur during conditions unfavorable for deep cloud-cluster formation with a drier mid-atmosphere. Cold pools help explain why cumulus congestus is common in the tropics.
Impact
We find that in one cloud-resolving simulation, the rain evaporation is too high, leading to an unrealistic moisture distribution. This may explain why, to date, understandings of cold pool processes through models and observations have not always agreed.
Summary
Cloud-resolving simulations capture realistic rain rates and surface wind changes (and thereby surface fluxes). The evolution in the model near-surface moisture field is unrealistic, however, with an erroneous moisture enhancement inside the cold pool edge that is attributed to rain evaporation. This supports a further focus on the model representation of cold pool frontal dynamics and mixing.