Dynamical influence of the Tibetan Plateau on the winter monsoon over southeastern Asia

Previous studies have shown (1) that the Tibetan Plateau produces a significant fraction of the two components of the Equatorial Mountain Torque (EMT) in winter, (2) that these torques are in part related to the East Asian cold surges, and (3) that the cold surges affect the convection over the maritime continent. We show here that these relations are strong enough for the convection over the Equatorial South China Sea to be associated with significant signals on the two components of the EMT that can precede by a few days and more the convection. These signals are associated to surface pressure and temperature patterns that are strongly reminiscent of the East Asian cold surges. Our results therefore show that the Tibetan Plateau couple dynamically the midlatitudes and the tropical region, and that the vectors of this dynamical coupling are the cold surges. This coupling also influences the convection over the northern Bay of Bengal, mainland southeast Asia, and Indonesia.