Climate change and the Madden‐Julian Oscillation: A vertically resolved weak temperature gradient analysis
Abstract WTG balance is used to examine how changes in the moist thermodynamic structure of the tropics affect the MJO in two simulations of the Superparameterized Community Earth System Model (SP‐CESM), one at preindustrial (PI) levels of CO2 and one where CO2 levels have been quadrupled (4×CO2). W...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2017-03-01
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| Series: | Journal of Advances in Modeling Earth Systems |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/2016MS000843 |
| _version_ | 1797736033817722880 |
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| author | Brandon O. Wolding Eric D. Maloney Stephanie Henderson Mark Branson |
| author_facet | Brandon O. Wolding Eric D. Maloney Stephanie Henderson Mark Branson |
| author_sort | Brandon O. Wolding |
| collection | DOAJ |
| description | Abstract WTG balance is used to examine how changes in the moist thermodynamic structure of the tropics affect the MJO in two simulations of the Superparameterized Community Earth System Model (SP‐CESM), one at preindustrial (PI) levels of CO2 and one where CO2 levels have been quadrupled (4×CO2). While MJO convective variability increases considerably in the 4×CO2 simulation, the dynamical response to this convective variability decreases. Increased MJO convective variability is shown to be a robust response to the steepening vertical moisture gradient, consistent with the findings of previous studies. The steepened vertical moisture gradient allows MJO convective heating to drive stronger variations in large‐scale vertical moisture advection, supporting destabilization of the MJO. The decreased dynamical response to MJO convective variability is shown to be a consequence of increased static stability, which allows weaker variations in large‐scale vertical velocity to produce sufficient adiabatic cooling to balance variations in MJO convective heating. This weakened dynamical response results in a considerable reduction of the MJO's ability to influence the extratropics, which is closely tied to the strength of its associated divergence. A composite lifecycle of the MJO was used to show that northern hemisphere extratropical 525 hPa geopotential height anomalies decreased by 27% in the 4×CO2 simulation, despite a 22% increase in tropical convective heating associated with the MJO. Results of this study suggest that while MJO convective variability may increase in a warming climate, the MJO's role in “bridging weather and climate” in the extratropics may not. |
| first_indexed | 2024-03-12T13:07:43Z |
| format | Article |
| id | doaj.art-d2b7b5ba4799451d9de3668f049516b3 |
| institution | Directory Open Access Journal |
| issn | 1942-2466 |
| language | English |
| last_indexed | 2024-03-12T13:07:43Z |
| publishDate | 2017-03-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj.art-d2b7b5ba4799451d9de3668f049516b32023-08-28T13:36:50ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662017-03-019130733110.1002/2016MS000843Climate change and the Madden‐Julian Oscillation: A vertically resolved weak temperature gradient analysisBrandon O. Wolding0Eric D. Maloney1Stephanie Henderson2Mark Branson3Department of Atmospheric ScienceColorado State UniversityFort Collins Colorado USADepartment of Atmospheric ScienceColorado State UniversityFort Collins Colorado USADepartment of Atmospheric ScienceColorado State UniversityFort Collins Colorado USADepartment of Atmospheric ScienceColorado State UniversityFort Collins Colorado USAAbstract WTG balance is used to examine how changes in the moist thermodynamic structure of the tropics affect the MJO in two simulations of the Superparameterized Community Earth System Model (SP‐CESM), one at preindustrial (PI) levels of CO2 and one where CO2 levels have been quadrupled (4×CO2). While MJO convective variability increases considerably in the 4×CO2 simulation, the dynamical response to this convective variability decreases. Increased MJO convective variability is shown to be a robust response to the steepening vertical moisture gradient, consistent with the findings of previous studies. The steepened vertical moisture gradient allows MJO convective heating to drive stronger variations in large‐scale vertical moisture advection, supporting destabilization of the MJO. The decreased dynamical response to MJO convective variability is shown to be a consequence of increased static stability, which allows weaker variations in large‐scale vertical velocity to produce sufficient adiabatic cooling to balance variations in MJO convective heating. This weakened dynamical response results in a considerable reduction of the MJO's ability to influence the extratropics, which is closely tied to the strength of its associated divergence. A composite lifecycle of the MJO was used to show that northern hemisphere extratropical 525 hPa geopotential height anomalies decreased by 27% in the 4×CO2 simulation, despite a 22% increase in tropical convective heating associated with the MJO. Results of this study suggest that while MJO convective variability may increase in a warming climate, the MJO's role in “bridging weather and climate” in the extratropics may not.https://doi.org/10.1002/2016MS000843Madden‐Julian Oscillationweak temperature gradientconvective aggregationtropicsclimate changeteleconnections |
| spellingShingle | Brandon O. Wolding Eric D. Maloney Stephanie Henderson Mark Branson Climate change and the Madden‐Julian Oscillation: A vertically resolved weak temperature gradient analysis Journal of Advances in Modeling Earth Systems Madden‐Julian Oscillation weak temperature gradient convective aggregation tropics climate change teleconnections |
| title | Climate change and the Madden‐Julian Oscillation: A vertically resolved weak temperature gradient analysis |
| title_full | Climate change and the Madden‐Julian Oscillation: A vertically resolved weak temperature gradient analysis |
| title_fullStr | Climate change and the Madden‐Julian Oscillation: A vertically resolved weak temperature gradient analysis |
| title_full_unstemmed | Climate change and the Madden‐Julian Oscillation: A vertically resolved weak temperature gradient analysis |
| title_short | Climate change and the Madden‐Julian Oscillation: A vertically resolved weak temperature gradient analysis |
| title_sort | climate change and the madden julian oscillation a vertically resolved weak temperature gradient analysis |
| topic | Madden‐Julian Oscillation weak temperature gradient convective aggregation tropics climate change teleconnections |
| url | https://doi.org/10.1002/2016MS000843 |
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