Dipole mode of the precipitation anomaly over the Tibetan Plateau in mid‐autumn associated with tropical Pacific–Indian Ocean sea surface temperature anomaly: Role of convection over the northern Maritime Continent

2021 ◽  
Author(s):  
Ping Zhang ◽  
Anmin Duan
Keyword(s):  
Indian Ocean ◽  
Tibetan Plateau ◽  
Temperature Anomaly ◽  
Precipitation Anomaly ◽  
Sea Surface ◽  
The Tibetan Plateau ◽  
Dipole Mode ◽  
Maritime Continent ◽  
Sea Surface Temperature Anomaly

scholarly journals Southern Hemisphere Origins for Interannual Variations of Snow Cover over the Western Tibetan Plateau in Boreal Summer

2018 ◽  
Vol 31 (19) ◽  
pp. 7701-7718 ◽  
Author(s):  
Juan Dou ◽  
Zhiwei Wu
Keyword(s):  
Indian Ocean ◽  
Tibetan Plateau ◽  
Snow Cover ◽  
Southern Hemisphere ◽  
Temperature Anomaly ◽  
Western Indian Ocean ◽  
Boreal Summer ◽  
The Tibetan Plateau ◽  
Interannual Variations ◽  
Wave Ray

The climate response to the Tibetan Plateau (TP) snow cover (TPSC) has been receiving extensive concern. However, relatively few studies have been devoted to revealing the potential factors that can contribute to the TPSC interannual variability, especially during boreal summer. This study finds that the May Southern Hemisphere (SH) annular mode (SAM), the dominating mode of atmospheric circulation variability in the SH extratropics, exhibits a significant positive relationship with the interannual variations in western TPSC during boreal summer. Observational analysis and numerical experiments manifest that the signal of the May SAM can be “prolonged” by a meridional Indian Ocean tripole (IOT) sea surface temperature anomaly (SSTA) via atmosphere–ocean interaction. The IOT SSTA pattern persists into the following summer and excites anomalous local-scale zonal–vertical circulation. Subsequently, a tropical dipole rainfall (TDR) mode is induced with precipitation anomalies between the tropical western Indian Ocean and the eastern Indian Ocean–Maritime Continent. Rossby wave ray tracing diagnosis reveals that the wave energies, generated by the latent heat release of the TDR mode, can propagate northward into the western TP. As a response, abnormal cyclone (or anticyclone) and upward (or downward) movement are triggered over the western TP, providing favorable dynamical conditions for more (or less) TPSC. Moreover, the strong May SAM is usually followed by a cold air temperature anomaly over the western TP in summer, which is unfavorable for snow-cover melting, and vice versa. In brief, the IOT SSTA plays an “ocean bridge” role and the TDR mode plays an “atmosphere bridge” role in the process of the May SAM impacting the following summer TPSC variability. The results may provide new insight into the cross-equatorial propagation of the SAM influence.

Sign in / Sign up

Export Citation Format

Share Document