Global Simulation of the Madden–Julian Oscillation With Stochastic Unified Convection Scheme
Abstract A new spectral convection scheme, the stochastic unified convection scheme (stochastic UNICON), is implemented in a general circulation model. The global climate simulation using stochastic UNICON is evaluated and compared with UNICON, focusing on the simulation of the Madden–Julian oscilla...
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2023-07-01
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| Series: | Journal of Advances in Modeling Earth Systems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2022MS003578 |
| _version_ | 1797647714925674496 |
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| author | Jihoon Shin Jong‐Jin Baik |
| author_facet | Jihoon Shin Jong‐Jin Baik |
| author_sort | Jihoon Shin |
| collection | DOAJ |
| description | Abstract A new spectral convection scheme, the stochastic unified convection scheme (stochastic UNICON), is implemented in a general circulation model. The global climate simulation using stochastic UNICON is evaluated and compared with UNICON, focusing on the simulation of the Madden–Julian oscillation (MJO). Stochastic UNICON extends the original UNICON by randomly sampling convective updrafts from the joint probability density function constructed at the near‐surface, generating a spectrum of convective updrafts in a physically based manner. The performances of UNICON and stochastic UNICON on simulating observed mean climates are comparable, while stochastic UNICON slightly reduces the mean bias of climate variables. For the simulation of intraseasonal variabilities, stochastic UNICON outperforms UNICON in many aspects. Stochastic UNICON improves the simulation of the intensity and propagation patterns of boreal winter MJO, which are too weakly simulated in UNICON. The coherency between MJO‐related convection and large‐scale circulation is also enhanced, which many climate models underestimate. The improvement of MJO simulation by stochastic UNICON is related to a better representation of the relationship between moisture and convection in the model. The increased frequency of shallow convection in stochastic UNICON leads to stronger moisture convergence that precedes convection activity peak and results in the more robust development of organized convection and more frequent intense precipitation. A precipitation budget analysis reveals that the moisture tendencies due to horizontal advection and convective process are consistently enhanced during MJO developing periods by stochastic UNICON. |
| first_indexed | 2024-03-11T15:21:31Z |
| format | Article |
| id | doaj.art-cbccb61cf05849ab99c28debf8c10bb4 |
| institution | Directory Open Access Journal |
| issn | 1942-2466 |
| language | English |
| last_indexed | 2024-03-11T15:21:31Z |
| publishDate | 2023-07-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj.art-cbccb61cf05849ab99c28debf8c10bb42023-10-28T13:31:25ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662023-07-01157n/an/a10.1029/2022MS003578Global Simulation of the Madden–Julian Oscillation With Stochastic Unified Convection SchemeJihoon Shin0Jong‐Jin Baik1School of Earth and Environmental Sciences Seoul National University Seoul South KoreaSchool of Earth and Environmental Sciences Seoul National University Seoul South KoreaAbstract A new spectral convection scheme, the stochastic unified convection scheme (stochastic UNICON), is implemented in a general circulation model. The global climate simulation using stochastic UNICON is evaluated and compared with UNICON, focusing on the simulation of the Madden–Julian oscillation (MJO). Stochastic UNICON extends the original UNICON by randomly sampling convective updrafts from the joint probability density function constructed at the near‐surface, generating a spectrum of convective updrafts in a physically based manner. The performances of UNICON and stochastic UNICON on simulating observed mean climates are comparable, while stochastic UNICON slightly reduces the mean bias of climate variables. For the simulation of intraseasonal variabilities, stochastic UNICON outperforms UNICON in many aspects. Stochastic UNICON improves the simulation of the intensity and propagation patterns of boreal winter MJO, which are too weakly simulated in UNICON. The coherency between MJO‐related convection and large‐scale circulation is also enhanced, which many climate models underestimate. The improvement of MJO simulation by stochastic UNICON is related to a better representation of the relationship between moisture and convection in the model. The increased frequency of shallow convection in stochastic UNICON leads to stronger moisture convergence that precedes convection activity peak and results in the more robust development of organized convection and more frequent intense precipitation. A precipitation budget analysis reveals that the moisture tendencies due to horizontal advection and convective process are consistently enhanced during MJO developing periods by stochastic UNICON.https://doi.org/10.1029/2022MS003578Madden–Julian oscillationstochastic parameterizationconvection parameterizationshallow convectionglobal climate model |
| spellingShingle | Jihoon Shin Jong‐Jin Baik Global Simulation of the Madden–Julian Oscillation With Stochastic Unified Convection Scheme Journal of Advances in Modeling Earth Systems Madden–Julian oscillation stochastic parameterization convection parameterization shallow convection global climate model |
| title | Global Simulation of the Madden–Julian Oscillation With Stochastic Unified Convection Scheme |
| title_full | Global Simulation of the Madden–Julian Oscillation With Stochastic Unified Convection Scheme |
| title_fullStr | Global Simulation of the Madden–Julian Oscillation With Stochastic Unified Convection Scheme |
| title_full_unstemmed | Global Simulation of the Madden–Julian Oscillation With Stochastic Unified Convection Scheme |
| title_short | Global Simulation of the Madden–Julian Oscillation With Stochastic Unified Convection Scheme |
| title_sort | global simulation of the madden julian oscillation with stochastic unified convection scheme |
| topic | Madden–Julian oscillation stochastic parameterization convection parameterization shallow convection global climate model |
| url | https://doi.org/10.1029/2022MS003578 |
| work_keys_str_mv | AT jihoonshin globalsimulationofthemaddenjulianoscillationwithstochasticunifiedconvectionscheme AT jongjinbaik globalsimulationofthemaddenjulianoscillationwithstochasticunifiedconvectionscheme |