What controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variation
Abstract The Hadley circulation is the most prominent atmospheric meridional circulation, reducing the radiatively driven equator-to-pole temperature gradient. While the Hadley cell extent varies by several degrees from year to year, the detailed dynamical mechanisms behind such variations have not...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2023-12-01
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| Series: | npj Climate and Atmospheric Science |
| Online Access: | https://doi.org/10.1038/s41612-023-00533-w |
| _version_ | 1797398073894240256 |
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| author | Kyong-Hwan Seo Sang-Pil Yoon Jian Lu Yongyun Hu Paul W. Staten Dargan M. W. Frierson |
| author_facet | Kyong-Hwan Seo Sang-Pil Yoon Jian Lu Yongyun Hu Paul W. Staten Dargan M. W. Frierson |
| author_sort | Kyong-Hwan Seo |
| collection | DOAJ |
| description | Abstract The Hadley circulation is the most prominent atmospheric meridional circulation, reducing the radiatively driven equator-to-pole temperature gradient. While the Hadley cell extent varies by several degrees from year to year, the detailed dynamical mechanisms behind such variations have not been well elucidated. During the expanded phase of the Hadley cell, many regions on the periphery of the subtropics experience unfavorable climatic conditions. In this study, using ERA5 reanalysis data, we examine the physical chain of events responsible for the interannual variation of the Hadley cell edge (HCE) latitude in the Northern Hemisphere. This variation is mainly caused by changing eddy activity and wave breaking from both stationary and transient waves. In particular, we show that transient waves cause the HCE to shift poleward by increasing the eddy momentum flux divergence (EMFD) and reducing the baroclinicity over 20°–40°N, shifting the region of peak baroclinicity poleward. El Niño/La Niña and the Arctic Oscillation (AO) account for a significant portion (60%) of the interannual fluctuation of the HCE latitude. Through the poleward displacement of eddy activity, La Niña and a positive AO state are associated with the poleward shift of the HCE. The analysis of 28 CMIP5 models reveals statistical relationships between EMFD, vertical shear, and HCE latitude similar to those observed. |
| first_indexed | 2024-03-09T01:20:25Z |
| format | Article |
| id | doaj.art-5b1aaa3874e4487db902500ff742b686 |
| institution | Directory Open Access Journal |
| issn | 2397-3722 |
| language | English |
| last_indexed | 2024-03-09T01:20:25Z |
| publishDate | 2023-12-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Climate and Atmospheric Science |
| spelling | doaj.art-5b1aaa3874e4487db902500ff742b6862023-12-10T12:12:51ZengNature Portfolionpj Climate and Atmospheric Science2397-37222023-12-016111210.1038/s41612-023-00533-wWhat controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variationKyong-Hwan Seo0Sang-Pil Yoon1Jian Lu2Yongyun Hu3Paul W. Staten4Dargan M. W. Frierson5Department of Atmospheric Sciences, Division of Earth Environmental System, Pusan National UniversityDepartment of Atmospheric Sciences, Division of Earth Environmental System, Pusan National UniversityPacific Northwest National LaboratoryDepartment of Atmospheric and Oceanic Sciences, School of Physics, Peking UniversityDepartment of Earth and Atmospheric Sciences, Indiana University BloomingtonDepartment of Atmospheric Sciences, University of WashingtonAbstract The Hadley circulation is the most prominent atmospheric meridional circulation, reducing the radiatively driven equator-to-pole temperature gradient. While the Hadley cell extent varies by several degrees from year to year, the detailed dynamical mechanisms behind such variations have not been well elucidated. During the expanded phase of the Hadley cell, many regions on the periphery of the subtropics experience unfavorable climatic conditions. In this study, using ERA5 reanalysis data, we examine the physical chain of events responsible for the interannual variation of the Hadley cell edge (HCE) latitude in the Northern Hemisphere. This variation is mainly caused by changing eddy activity and wave breaking from both stationary and transient waves. In particular, we show that transient waves cause the HCE to shift poleward by increasing the eddy momentum flux divergence (EMFD) and reducing the baroclinicity over 20°–40°N, shifting the region of peak baroclinicity poleward. El Niño/La Niña and the Arctic Oscillation (AO) account for a significant portion (60%) of the interannual fluctuation of the HCE latitude. Through the poleward displacement of eddy activity, La Niña and a positive AO state are associated with the poleward shift of the HCE. The analysis of 28 CMIP5 models reveals statistical relationships between EMFD, vertical shear, and HCE latitude similar to those observed.https://doi.org/10.1038/s41612-023-00533-w |
| spellingShingle | Kyong-Hwan Seo Sang-Pil Yoon Jian Lu Yongyun Hu Paul W. Staten Dargan M. W. Frierson What controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variation npj Climate and Atmospheric Science |
| title | What controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variation |
| title_full | What controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variation |
| title_fullStr | What controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variation |
| title_full_unstemmed | What controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variation |
| title_short | What controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variation |
| title_sort | what controls the interannual variation of hadley cell extent in the northern hemisphere physical mechanism and empirical model for edge variation |
| url | https://doi.org/10.1038/s41612-023-00533-w |
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