Improved Precipitation Diurnal Cycle in GFDL Climate Models With Non‐Equilibrium Convection
Abstract Most global climate models with convective parameterization have trouble in simulating the observed diurnal cycle of convection. Maximum precipitation usually happens too early during summertime, especially over land. Observational analyses indicate that deep convection over land cannot kee...
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2024-09-01
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| Series: | Journal of Advances in Modeling Earth Systems |
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| Online Access: | https://doi.org/10.1029/2024MS004315 |
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| author | Bosong Zhang Leo J. Donner Ming Zhao Zhihong Tan |
| author_facet | Bosong Zhang Leo J. Donner Ming Zhao Zhihong Tan |
| author_sort | Bosong Zhang |
| collection | DOAJ |
| description | Abstract Most global climate models with convective parameterization have trouble in simulating the observed diurnal cycle of convection. Maximum precipitation usually happens too early during summertime, especially over land. Observational analyses indicate that deep convection over land cannot keep pace with rapid variations in convective available potential energy, which is largely controlled by boundary‐layer forcing. In this study, a new convective closure in which shallow and deep convection interact strongly, out of equilibrium, is implemented in atmosphere‐only and ocean‐atmosphere coupled models. The diurnal cycles of convection in both simulations are significantly improved with small changes to their mean states. The new closure shifts maximum precipitation over land later by about three hours. Compared to satellite observations, the diurnal phase biases are reduced by half. Shallow convection to some extent equilibrates rapid changes in the boundary layer at subdiurnal time scales. Relaxed quasi‐equilibrium for convective available potential energy holds in significant measure as a result. Future model improvement will focus on the remaining biases in the diurnal cycle, which may be further reduced by including stochastic entrainment and cold pools. |
| format | Article |
| id | doaj-art-19cf9c3d67664a4299ea5c30e710281e |
| institution | OA Journals |
| issn | 1942-2466 |
| language | English |
| publishDate | 2024-09-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj-art-19cf9c3d67664a4299ea5c30e710281e2025-08-20T01:55:12ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662024-09-01169n/an/a10.1029/2024MS004315Improved Precipitation Diurnal Cycle in GFDL Climate Models With Non‐Equilibrium ConvectionBosong Zhang0Leo J. Donner1Ming Zhao2Zhihong Tan3Program in Atmospheric and Oceanic Sciences Princeton University Princeton NJ USANOAA/Geophysical Fluid Dynamics Laboratory Princeton NJ USANOAA/Geophysical Fluid Dynamics Laboratory Princeton NJ USAProgram in Atmospheric and Oceanic Sciences Princeton University Princeton NJ USAAbstract Most global climate models with convective parameterization have trouble in simulating the observed diurnal cycle of convection. Maximum precipitation usually happens too early during summertime, especially over land. Observational analyses indicate that deep convection over land cannot keep pace with rapid variations in convective available potential energy, which is largely controlled by boundary‐layer forcing. In this study, a new convective closure in which shallow and deep convection interact strongly, out of equilibrium, is implemented in atmosphere‐only and ocean‐atmosphere coupled models. The diurnal cycles of convection in both simulations are significantly improved with small changes to their mean states. The new closure shifts maximum precipitation over land later by about three hours. Compared to satellite observations, the diurnal phase biases are reduced by half. Shallow convection to some extent equilibrates rapid changes in the boundary layer at subdiurnal time scales. Relaxed quasi‐equilibrium for convective available potential energy holds in significant measure as a result. Future model improvement will focus on the remaining biases in the diurnal cycle, which may be further reduced by including stochastic entrainment and cold pools.https://doi.org/10.1029/2024MS004315deep convectionshallow convectiondiurnal cycle of precipitation |
| spellingShingle | Bosong Zhang Leo J. Donner Ming Zhao Zhihong Tan Improved Precipitation Diurnal Cycle in GFDL Climate Models With Non‐Equilibrium Convection Journal of Advances in Modeling Earth Systems deep convection shallow convection diurnal cycle of precipitation |
| title | Improved Precipitation Diurnal Cycle in GFDL Climate Models With Non‐Equilibrium Convection |
| title_full | Improved Precipitation Diurnal Cycle in GFDL Climate Models With Non‐Equilibrium Convection |
| title_fullStr | Improved Precipitation Diurnal Cycle in GFDL Climate Models With Non‐Equilibrium Convection |
| title_full_unstemmed | Improved Precipitation Diurnal Cycle in GFDL Climate Models With Non‐Equilibrium Convection |
| title_short | Improved Precipitation Diurnal Cycle in GFDL Climate Models With Non‐Equilibrium Convection |
| title_sort | improved precipitation diurnal cycle in gfdl climate models with non equilibrium convection |
| topic | deep convection shallow convection diurnal cycle of precipitation |
| url | https://doi.org/10.1029/2024MS004315 |
| work_keys_str_mv | AT bosongzhang improvedprecipitationdiurnalcycleingfdlclimatemodelswithnonequilibriumconvection AT leojdonner improvedprecipitationdiurnalcycleingfdlclimatemodelswithnonequilibriumconvection AT mingzhao improvedprecipitationdiurnalcycleingfdlclimatemodelswithnonequilibriumconvection AT zhihongtan improvedprecipitationdiurnalcycleingfdlclimatemodelswithnonequilibriumconvection |