Vertically Varying Cloud Responses to Southern Hemisphere Jet Shifts and Their Role in Southern Annular Mode Persistence in Observations and CMIP6 Models
Abstract This study investigates how clouds and their atmospheric radiative effects respond to meridional shifts in the Southern Hemisphere (SH) mid‐latitude jet, represented by the Southern Annular Mode (SAM), using reanalysis data, CloudSat/CALIPSO observations, and CMIP6 models. Consistent with p...
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| Format: | Article |
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Wiley
2025-07-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2024GL114550 |
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| author | Xinhuiyu Liu Kevin M. Grise |
| author_facet | Xinhuiyu Liu Kevin M. Grise |
| author_sort | Xinhuiyu Liu |
| collection | DOAJ |
| description | Abstract This study investigates how clouds and their atmospheric radiative effects respond to meridional shifts in the Southern Hemisphere (SH) mid‐latitude jet, represented by the Southern Annular Mode (SAM), using reanalysis data, CloudSat/CALIPSO observations, and CMIP6 models. Consistent with previous studies, poleward jet shifts displace storm‐track clouds, creating lower tropospheric radiative heating anomalies poleward of the mean jet latitude and cooling anomalies on the equatorward side of the mean jet latitude where large‐scale subsidence increases low cloud fraction. Whether these radiative heating anomalies can affect SAM persistence is also investigated in CMIP6 models. If observed sea surface temperatures are prescribed, models that simulate low cloud responses more realistically show less SAM persistence, aligning more closely with observations. Our results based on CMIP6 models agree with a recent idealized modeling study and suggest that atmospheric cloud radiative heating anomalies, induced by the poleward jet shift, contribute to a reduction in SAM persistence. |
| format | Article |
| id | doaj-art-6bf2f9b7a8014b808a13166454009ea5 |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-6bf2f9b7a8014b808a13166454009ea52025-08-20T03:39:32ZengWileyGeophysical Research Letters0094-82761944-80072025-07-015213n/an/a10.1029/2024GL114550Vertically Varying Cloud Responses to Southern Hemisphere Jet Shifts and Their Role in Southern Annular Mode Persistence in Observations and CMIP6 ModelsXinhuiyu Liu0Kevin M. Grise1Department of Environmental Sciences University of Virginia Charlottesville VA USADepartment of Environmental Sciences University of Virginia Charlottesville VA USAAbstract This study investigates how clouds and their atmospheric radiative effects respond to meridional shifts in the Southern Hemisphere (SH) mid‐latitude jet, represented by the Southern Annular Mode (SAM), using reanalysis data, CloudSat/CALIPSO observations, and CMIP6 models. Consistent with previous studies, poleward jet shifts displace storm‐track clouds, creating lower tropospheric radiative heating anomalies poleward of the mean jet latitude and cooling anomalies on the equatorward side of the mean jet latitude where large‐scale subsidence increases low cloud fraction. Whether these radiative heating anomalies can affect SAM persistence is also investigated in CMIP6 models. If observed sea surface temperatures are prescribed, models that simulate low cloud responses more realistically show less SAM persistence, aligning more closely with observations. Our results based on CMIP6 models agree with a recent idealized modeling study and suggest that atmospheric cloud radiative heating anomalies, induced by the poleward jet shift, contribute to a reduction in SAM persistence.https://doi.org/10.1029/2024GL114550atmospheric cloud radiative effectsjet streamsouthern annular modeMERRA2 reanalysisCloudSat/CALIPSOCMIP6 |
| spellingShingle | Xinhuiyu Liu Kevin M. Grise Vertically Varying Cloud Responses to Southern Hemisphere Jet Shifts and Their Role in Southern Annular Mode Persistence in Observations and CMIP6 Models Geophysical Research Letters atmospheric cloud radiative effects jet stream southern annular mode MERRA2 reanalysis CloudSat/CALIPSO CMIP6 |
| title | Vertically Varying Cloud Responses to Southern Hemisphere Jet Shifts and Their Role in Southern Annular Mode Persistence in Observations and CMIP6 Models |
| title_full | Vertically Varying Cloud Responses to Southern Hemisphere Jet Shifts and Their Role in Southern Annular Mode Persistence in Observations and CMIP6 Models |
| title_fullStr | Vertically Varying Cloud Responses to Southern Hemisphere Jet Shifts and Their Role in Southern Annular Mode Persistence in Observations and CMIP6 Models |
| title_full_unstemmed | Vertically Varying Cloud Responses to Southern Hemisphere Jet Shifts and Their Role in Southern Annular Mode Persistence in Observations and CMIP6 Models |
| title_short | Vertically Varying Cloud Responses to Southern Hemisphere Jet Shifts and Their Role in Southern Annular Mode Persistence in Observations and CMIP6 Models |
| title_sort | vertically varying cloud responses to southern hemisphere jet shifts and their role in southern annular mode persistence in observations and cmip6 models |
| topic | atmospheric cloud radiative effects jet stream southern annular mode MERRA2 reanalysis CloudSat/CALIPSO CMIP6 |
| url | https://doi.org/10.1029/2024GL114550 |
| work_keys_str_mv | AT xinhuiyuliu verticallyvaryingcloudresponsestosouthernhemispherejetshiftsandtheirroleinsouthernannularmodepersistenceinobservationsandcmip6models AT kevinmgrise verticallyvaryingcloudresponsestosouthernhemispherejetshiftsandtheirroleinsouthernannularmodepersistenceinobservationsandcmip6models |