Formulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulations
Abstract This study formulates and implements a dynamic convective adjustment time-scale $$\:(\tau\:$$ ) in the convective parameterization scheme of CESM1.2, replacing the default fixed $$\:\tau\:$$ . By allowing $$\:\tau\:$$ to vary spatiotemporally with convective cloud depth and updraft velocity...
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Nature Portfolio
2025-08-01
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| Series: | Scientific Reports |
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| Online Access: | https://doi.org/10.1038/s41598-025-15073-x |
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| author | Raju Pathak Sandeep Sahany Saroj Kanta Mishra Jingyu Wang |
| author_facet | Raju Pathak Sandeep Sahany Saroj Kanta Mishra Jingyu Wang |
| author_sort | Raju Pathak |
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| description | Abstract This study formulates and implements a dynamic convective adjustment time-scale $$\:(\tau\:$$ ) in the convective parameterization scheme of CESM1.2, replacing the default fixed $$\:\tau\:$$ . By allowing $$\:\tau\:$$ to vary spatiotemporally with convective cloud depth and updraft velocity, the approach significantly improves Indian summer monsoon simulations. The scheme reduces longstanding precipitation biases, such as excessive precipitation over the Himalayas, Western Ghats, and peninsular India, and underestimations over the eastern equatorial Indian Ocean. The scheme also enhances cloud cover characteristics, particularly the low cloud cover, radiative forcing, and large-scale circulation (subtropical westerly Jet and Somali Jet). Limited improvement in the monsoon quasi-biweekly and intraseasonal mode and precipitation variability, is seen. Despite these improvements, regional biases, extreme event underestimation, intraseasonal oscillations, and ocean-atmosphere coupling limitations persist. These findings underscore the potential of dynamic convective adjustment in reducing key monsoon simulation biases and improving long-term climate projections in global models. |
| format | Article |
| id | doaj-art-e5e5e07bca654a3f97286dd23f0fb19d |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj-art-e5e5e07bca654a3f97286dd23f0fb19d2025-08-20T03:45:56ZengNature PortfolioScientific Reports2045-23222025-08-0115111410.1038/s41598-025-15073-xFormulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulationsRaju Pathak0Sandeep Sahany1Saroj Kanta Mishra2Jingyu Wang3Centre for Atmospheric Sciences, Indian Institute of Technology DelhiCentre for Atmospheric Sciences, Indian Institute of Technology DelhiCentre for Atmospheric Sciences, Indian Institute of Technology DelhiNational Institute of Education, Nanyang Technological UniversityAbstract This study formulates and implements a dynamic convective adjustment time-scale $$\:(\tau\:$$ ) in the convective parameterization scheme of CESM1.2, replacing the default fixed $$\:\tau\:$$ . By allowing $$\:\tau\:$$ to vary spatiotemporally with convective cloud depth and updraft velocity, the approach significantly improves Indian summer monsoon simulations. The scheme reduces longstanding precipitation biases, such as excessive precipitation over the Himalayas, Western Ghats, and peninsular India, and underestimations over the eastern equatorial Indian Ocean. The scheme also enhances cloud cover characteristics, particularly the low cloud cover, radiative forcing, and large-scale circulation (subtropical westerly Jet and Somali Jet). Limited improvement in the monsoon quasi-biweekly and intraseasonal mode and precipitation variability, is seen. Despite these improvements, regional biases, extreme event underestimation, intraseasonal oscillations, and ocean-atmosphere coupling limitations persist. These findings underscore the potential of dynamic convective adjustment in reducing key monsoon simulation biases and improving long-term climate projections in global models.https://doi.org/10.1038/s41598-025-15073-xCESMConvective parameterizationTime-scaleIndian summer monsoonPrecipitation |
| spellingShingle | Raju Pathak Sandeep Sahany Saroj Kanta Mishra Jingyu Wang Formulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulations Scientific Reports CESM Convective parameterization Time-scale Indian summer monsoon Precipitation |
| title | Formulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulations |
| title_full | Formulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulations |
| title_fullStr | Formulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulations |
| title_full_unstemmed | Formulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulations |
| title_short | Formulation of a dynamic convective adjustment time-scale in the CESM1.2 and its influence on the Indian summer monsoon simulations |
| title_sort | formulation of a dynamic convective adjustment time scale in the cesm1 2 and its influence on the indian summer monsoon simulations |
| topic | CESM Convective parameterization Time-scale Indian summer monsoon Precipitation |
| url | https://doi.org/10.1038/s41598-025-15073-x |
| work_keys_str_mv | AT rajupathak formulationofadynamicconvectiveadjustmenttimescaleinthecesm12anditsinfluenceontheindiansummermonsoonsimulations AT sandeepsahany formulationofadynamicconvectiveadjustmenttimescaleinthecesm12anditsinfluenceontheindiansummermonsoonsimulations AT sarojkantamishra formulationofadynamicconvectiveadjustmenttimescaleinthecesm12anditsinfluenceontheindiansummermonsoonsimulations AT jingyuwang formulationofadynamicconvectiveadjustmenttimescaleinthecesm12anditsinfluenceontheindiansummermonsoonsimulations |