Jingxuan Cui

MJO propagation features changes under global warming

The MJO plays an important role in affecting global weather and climate. How do MJO features change under the on-going global warming? In two selected CMIP5 models, the MJO propagation tends to be accelerated, associated with the anomalous circulation changes. The relative role of anomalous heating and mean static stability changes in determining MJO-scale circulation change was revealed by constructing a theoretical framework. During the initial warming phase, the circulation change is primarily controlled by the heating change, whereas during the later warming phase, it is primarily controlled by the static stability change.

MJO representations in reanalysis products with only surface variables assimilated

Current state-of-the-art atmospheric circulation models have difficulty reproducing observed MJO characteristics when forced by observed daily sea surface temperature alone. An important practical question is how much data a model needs in assimilation to reproduce real MJO events. By analyzing ERA-20C and NOAA-20CR reanalysis data, we found a model could reproduce observed MJO for both vertical structure and propagation features by assimilating the observed surface signal alone. It serves as a reference that the assimilation of atmospheric low-level signals may be given priority in future studies related to the MJO.

MJO teleconnection changes in the PNA region

How the MJO teleconnections change in a warmer climate has a great influence on a wide range of extratropical weather events. The teleconnections in the PNA region tend to be stronger and have an eastward extension in CESM2 large ensemble product. It provides important information on how extreme weather in North America may change in a warmer climate, and indicate that understanding both changes to the basic state and MJO characteristics in a warmer climate is necessary for understanding teleconnection changes.

How did MJO-related precipitation change on the global scale?

MJO-induced tropical and midlatitude precipitation and associated extremes and high-frequency variabilities were strengthened during the past century while the global mean surface temperature increases approximately by 1 degree Celsius. It shows evidence that the MJO plays an important role in affecting global weather events, and provides a basis for improving the extended-range prediction of severe weather and climate extremes.