Interactions between the MJO and its embedded Mesoscale Convective Systems
Abstract
The MaddenJulian oscillation (MJO), with a period of 3060 days, is a dominant mode of tropical intra-seasonal variability. It significantly affects tropical and extratropical climate and weather patterns through teleconnection. Within its convective envelope, the MJO often features numerous mesoscale convective systems (MCSs), which contribute to more than 50% of the total rainfall over most tropical regions. The cross-scale interactions between the MJOs and their embedded MCSs are investigated by utilizing a newly developed high-resolution MCS tracking database (Feng et al. 2021) with an MJO precipitation tracking dataset (Kerns and Chen, 2020). Results suggest that during boreal winter, MCSs embedded within the MJO events can propagate both eastward and westward, although westward propagating MCSs are more frequent, with a percentage of more than 60%. The percentage of westward propagating MCSs decreases as the MJO events propagate from the Indian Ocean to the western Pacific. The MJO zonal propagation speed is found to highly correlate with the fraction of westward propagating MCSs. The effect of the MJO large-scale circulation on the MCSs is being investigated by combining the ERA5 reanalysis products with the MJO and MCS databases. Improved understanding of the interactions between MCSs and the MJO may provide useful information in diagnosing biases in current global climate models, which have limited skill in representing the MJO.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.A52G..07L