Investigating Convective Processes Underlying ENSO: New Insights Into the Fixed Anvil Temperature Hypothesis

Abstract Interannual variations provide insight into the sensitivity of convective processes. Thus, CloudSat and ERA5 are used to explore the relationship among convective cores, outflows and environmental conditions during El Niño‐Southern Oscillation (ENSO) cycles. Results reveal greater upper‐tro...

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Main Authors: Hanii Takahashi, Zhengzhao Johnny Luo, Hirohiko Masunaga, Rachel Storer, Akira T. Noda
Format: Article
Language:English
Published: Wiley 2024-03-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2023GL107113
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author Hanii Takahashi
Zhengzhao Johnny Luo
Hirohiko Masunaga
Rachel Storer
Akira T. Noda
author_facet Hanii Takahashi
Zhengzhao Johnny Luo
Hirohiko Masunaga
Rachel Storer
Akira T. Noda
author_sort Hanii Takahashi
collection DOAJ
description Abstract Interannual variations provide insight into the sensitivity of convective processes. Thus, CloudSat and ERA5 are used to explore the relationship among convective cores, outflows and environmental conditions during El Niño‐Southern Oscillation (ENSO) cycles. Results reveal greater upper‐tropospheric stability during El Niño, resulting in a lower level of neutral buoyancy compared to La Niña. However, outflow levels remain relatively consistent across ENSO cycles. This suggests that, despite less favorable conditions for deep convection during El Niño, stronger convective intensity is required to achieve outflow levels comparable to those in La Niña. Indeed, our results suggest that convection observed during El Niño tends to have broader cores and lower entrainment rates, translating to greater intensity compared to La Niña. These findings emphasize the importance of considering both large‐scale and convective‐scale processes, providing an update to the fixed anvil temperature (FAT) and the proportionately higher anvil temperature (PHAT) hypotheses as originally proposed.
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series Geophysical Research Letters
spelling doaj-art-dc7a2e2b7d6c4723aed317e5a6a89f8d2025-08-20T02:31:37ZengWileyGeophysical Research Letters0094-82761944-80072024-03-01516n/an/a10.1029/2023GL107113Investigating Convective Processes Underlying ENSO: New Insights Into the Fixed Anvil Temperature HypothesisHanii Takahashi0Zhengzhao Johnny Luo1Hirohiko Masunaga2Rachel Storer3Akira T. Noda4Jet Propulsion Laboratory California Institute of Technology Pasadena CA USADepartment of Earth and Atmospheric Sciences the City College of New York of City University of New York New York NY USAInstitute for Space‐Earth Environmental Research Nagoya University Nagoya JapanJet Propulsion Laboratory California Institute of Technology Pasadena CA USAJapan Agency for Marine‐Earth Science and Technology Yokohama JapanAbstract Interannual variations provide insight into the sensitivity of convective processes. Thus, CloudSat and ERA5 are used to explore the relationship among convective cores, outflows and environmental conditions during El Niño‐Southern Oscillation (ENSO) cycles. Results reveal greater upper‐tropospheric stability during El Niño, resulting in a lower level of neutral buoyancy compared to La Niña. However, outflow levels remain relatively consistent across ENSO cycles. This suggests that, despite less favorable conditions for deep convection during El Niño, stronger convective intensity is required to achieve outflow levels comparable to those in La Niña. Indeed, our results suggest that convection observed during El Niño tends to have broader cores and lower entrainment rates, translating to greater intensity compared to La Niña. These findings emphasize the importance of considering both large‐scale and convective‐scale processes, providing an update to the fixed anvil temperature (FAT) and the proportionately higher anvil temperature (PHAT) hypotheses as originally proposed.https://doi.org/10.1029/2023GL107113convective outflowentrainmentconvective coresENSOFATPHAT
spellingShingle Hanii Takahashi
Zhengzhao Johnny Luo
Hirohiko Masunaga
Rachel Storer
Akira T. Noda
Investigating Convective Processes Underlying ENSO: New Insights Into the Fixed Anvil Temperature Hypothesis
Geophysical Research Letters
convective outflow
entrainment
convective cores
ENSO
FAT
PHAT
title Investigating Convective Processes Underlying ENSO: New Insights Into the Fixed Anvil Temperature Hypothesis
title_full Investigating Convective Processes Underlying ENSO: New Insights Into the Fixed Anvil Temperature Hypothesis
title_fullStr Investigating Convective Processes Underlying ENSO: New Insights Into the Fixed Anvil Temperature Hypothesis
title_full_unstemmed Investigating Convective Processes Underlying ENSO: New Insights Into the Fixed Anvil Temperature Hypothesis
title_short Investigating Convective Processes Underlying ENSO: New Insights Into the Fixed Anvil Temperature Hypothesis
title_sort investigating convective processes underlying enso new insights into the fixed anvil temperature hypothesis
topic convective outflow
entrainment
convective cores
ENSO
FAT
PHAT
url https://doi.org/10.1029/2023GL107113
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AT hirohikomasunaga investigatingconvectiveprocessesunderlyingensonewinsightsintothefixedanviltemperaturehypothesis
AT rachelstorer investigatingconvectiveprocessesunderlyingensonewinsightsintothefixedanviltemperaturehypothesis
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