@article{d5cc8d90b76c40d88c593ebf0ab3b8f8,
title = "Moisture Distributions in Tropical Cold Pools From Equatorial Indian Ocean Observations and Cloud-Resolving Simulations",
abstract = "The near-surface characteristics of approximately 300 convective cold pools over the equatorial Indian Ocean are studied using surface meteorological variables from two equatorial Indian Ocean sites, radar imagery, and constrained cloud-resolving simulations. The observed temperature drop at cold pool onset is typically accompanied by a drying and a decrease in moist static energy, signifying air transport from above the boundary layer through precipitation-induced downdrafts. The decrease in the surface water vapor mixing ratio is more pronounced for stronger temperature drops. Composites reveal a slight enhancement in moisture coincident with a slight enhancement in temperature prior to the cold pool frontal temperature drop. The slight enhancements occur prior to a gust of increased surface winds, suggesting that the immediate cause is wind convergence. A statistical analysis combined with a focus on selected case studies is consistent with a view that the strongest cold pools occur in intermediate column water vapor paths with drier midtropospheres. Such conditions are more likely to occur during convectively suppressed phases of the Madden-Julian Oscillation, when cold pool mesoscale organization facilitates the ability of cumulus congestus to reach the middle troposphere. Cold pools thus help explain why tropical cumulus congestus are common. 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.",
keywords = "DYNAMO, Indian Ocean, MJO, cold pools, convection",
author = "Chandra, {Arunchandra S.} and Paquita Zuidema and Steven Krueger and Adam Kochanski and {de Szoeke}, {Simon P.} and Jianhao Zhang",
note = "Funding Information: We gratefully acknowledge support from NOAA Climate Variability Program grants NA13OAR4310157 and NA130AR4310158, and NSF grant AGS-132189. We gratefully acknowledge use of DOE ARM data from the AMIE project. The discussion of the individual cases in Figure benefitted from the excellent daily summaries made publicly available by Robert Houze at the University of Washington. We thank Bob Rilling at the National Center for Atmospheric Science for the S-Pol and SMART-R quick look imagery within Figures. The SAM model output is available through the University of Miami scholarly repository at https://doi.org/10.17604/5d4a-qj11; we thank Tim Norris for his assistance. Three anonymous reviewers provided thoughtful comments that improved the final manuscript, including a pointer to von Karman's original 1940 paper. P.?Z. also thanks Bjorn Stevens and Raphaela Vogel for discussion. Funding Information: We gratefully acknowledge support from NOAA Climate Variability Program grants NA13OAR4310157 and NA130AR4310158, and NSF grant AGS-132189. We gratefully acknowledge use of DOE ARM data from the AMIE project. The discussion of the individual cases in Figure 9 benefitted from the excellent daily summaries made publicly available by Robert Houze at the University of Washington. We thank Bob Rilling at the National Center for Atmospheric Science for the S-Pol and SMART-R quick look imagery within Figures 4. The SAM model output is available through the University of Miami scholarly repository at https://doi.org/10.17604/5d4a-qj11; we thank Tim Norris for his assistance. Three anonymous reviewers provided thoughtful comments that improved the final manuscript, including a pointer to von Karman{\textquoteright}s original 1940 paper. P. Z. also thanks Bjorn Stevens and Raphaela Vogel for discussion. Publisher Copyright: {\textcopyright}2018. American Geophysical Union. All Rights Reserved.",
year = "2018",
month = oct,
day = "27",
doi = "10.1029/2018JD028634",
language = "English (US)",
volume = "123",
pages = "11,445--11,465",
journal = "Journal of Geophysical Research: Atmospheres",
issn = "2169-897X",
number = "20",
}