Abstract Recent work using CMIP5 models under RCP8.5 suggests that individual multimodel mean changes in precipitation and wind variability associated with the Madden‐Julian oscillation (MJO) are not detectable until the end of the 21st century. However, a decrease in the ratio of MJO circulation to precipitation anomaly amplitude is detectable as early as 2021–2040, consistent with an increase in dry static stability as predicted by weak temperature gradient balance. Here, we examine MJO activity in multiple reanalyses (ERA5, MERRA‐2, and ERA‐20C) and find that MJO wind and precipitation anomaly amplitudes have a complicated time evolution over the record. However, a decrease in the ratio of MJO circulation to precipitation anomaly amplitude is detected over the observational period, consistent with the change in dry static stability. These results suggest that weak temperature gradient theory may be able to help explain changes in MJO activity in recent decades.
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Emergence of Madden-Julian oscillation precipitation and wind amplitude changes in a warming climate
Abstract The Madden-Julian oscillation (MJO) has profound impacts on weather and climate phenomena, and thus changes in its activity have important implications under human-induced global climate change. Here, the time at which the MJO change signal emerges from natural variability under anthropogenic warming is investigated. Using simulations of the Community Earth System Model version 2 large ensemble forced by the shared socioeconomic pathways SSP370 scenario, an increase in ensemble mean MJO precipitation amplitude and a smaller increase in MJO circulation amplitude occur by the end of the 21 st century, consistent with previous studies. Notably, the MJO precipitation amplitude change signal generally emerges more than a decade earlier than that of MJO wind amplitude. MJO amplitude changes also emerge earlier over the eastern Pacific than other parts of the tropics. Our findings provide valuable information on the potential changes of MJO variability with the aim of improving predictions of the MJO and its associated extreme events.
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- Award ID(s):
- 1841754
- PAR ID:
- 10415281
- Date Published:
- Journal Name:
- npj Climate and Atmospheric Science
- Volume:
- 6
- Issue:
- 1
- ISSN:
- 2397-3722
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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