TY - JOUR
T1 - Diurnal Cloud and Circulation Changes in Simulated Tropical Cyclones
AU - Ruppert, James H.
AU - O'Neill, Morgan E.
N1 - Funding Information:
J. H. R. gratefully acknowledges funding for this research from the National Science Foundation (grant AGS-1524844) and Alexander von Humboldt Foundation/Stiftung. M. E O. was primarily supported by the T. C. Chamberlin Postdoctoral Fellowship at the University of Chicago during this work. We thank Guido Cioni and two anonymous reviewers for their very constructive comments. We acknowledge Cathy Hohenegger and the Deutsches Klimarechenzentrum (DKRZ) for providing access to supercomputing resources. Model source code, start data, representative model output, and preprocessing and postprocessing scripts used in this study are archived by the Max Planck Institute for Meteorology and may be freely obtained with no restrictions from the online database at https://pure.mpg.de/pubman/faces/HomePage.jsp.
Funding Information:
J. H. R. gratefully acknowledges funding for this research from the National Science Foundation (grant AGS-1524844) and Alexander von Humboldt Foundation/Stiftung. M. E O. was primarily supported by the T. C. Chamberlin Postdoctoral Fellowship at the University of Chicago during this work. We thank Guido Cioni and two anonymous reviewers for their very constructive comments. We acknowledge Cathy Hohenegger and the Deutsches Klimarechenzentrum (DKRZ) for providing access to supercomputing resources. Model source code, start data, representative model output, and preprocessing and postprocessing scripts used in this study are archived by the Max Planck Institute for Meteorology and may be freely obtained with no restrictions from the online database at https://pure.mpg.de/pubman/faces/ HomePage.jsp.
Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/1/16
Y1 - 2019/1/16
N2 - Observations of the diurnal cycle in tropical cyclones (TCs) systematically indicate a ∼12-hr offset between peak rainfall rate and the maximum height of anvil clouds in the TC cloud canopy. This phasing conflicts with archetypal models of organized deep convection, which suggest a tight coupling between rainfall, vertical cloud growth, and anvil clouds. We show that this phasing owes to the bimodal diurnal evolution of the transverse circulation, which peaks nocturnally from low–midlevels, and during daytime in the upper troposphere. The bottom-heavy nocturnal circulation state is driven by latent heating from nocturnally invigorated deep convection, while the top-heavy daytime state is the thermally direct circulation response to strong shortwave-cloud warming in the optically thick TC cloud canopy. This daytime upper-level circulation response manifests in a lifting of the maximum height of the TC outflow and, in turn, a lifting and invigoration of the upper-level anvil clouds of the TC cloud canopy.
AB - Observations of the diurnal cycle in tropical cyclones (TCs) systematically indicate a ∼12-hr offset between peak rainfall rate and the maximum height of anvil clouds in the TC cloud canopy. This phasing conflicts with archetypal models of organized deep convection, which suggest a tight coupling between rainfall, vertical cloud growth, and anvil clouds. We show that this phasing owes to the bimodal diurnal evolution of the transverse circulation, which peaks nocturnally from low–midlevels, and during daytime in the upper troposphere. The bottom-heavy nocturnal circulation state is driven by latent heating from nocturnally invigorated deep convection, while the top-heavy daytime state is the thermally direct circulation response to strong shortwave-cloud warming in the optically thick TC cloud canopy. This daytime upper-level circulation response manifests in a lifting of the maximum height of the TC outflow and, in turn, a lifting and invigoration of the upper-level anvil clouds of the TC cloud canopy.
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U2 - 10.1029/2018GL081302
DO - 10.1029/2018GL081302
M3 - Article
AN - SCOPUS:85059951418
VL - 46
SP - 502
EP - 511
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 1
ER -