A Teleconnection Pattern over Eurasian Continent in early Spring and its Impact on Bay of Bangle Monsoon Onset

A teleconnection pattern over the Eurasian continent in early spring and its impact on Bay of Bangle Monsoon onset, is investigated on the basis of reanalysis datasets and numerical test. It is revealed that this pattern shows Rossby wave activities that excited by the forcing feedback of the transient eddies over the exit region of the North Atlantic jet. The anomalous centers can manifest themselves as Rossby wave dividing into two branches and propagating towards Lake Baikal and south flank of the Tibetan Plateau. Meanwhile, asymmetric atmospheric response to vorticity forcing is characterized by weaker amplitude during positive phase than negative phase, which is caused by weaker positive vorticity forcing. Moreover, the anomalous cold cyclone locates on the Tibetan Plateau can bring more snowfall and correspond to anomalously wet soil condition, thereby decreasing surface heat flux and near-surface temperatures, leading to an anomalous cold cyclone can be maintained until April. Therefore, it can postpone Bay of Bangle Monsoon onset. Subsequently, the interannual variations of stationary wave can give a better explanation for late Monsoon onset under neutral ENSO condition. The simulated response to vorticity forcing also can reproduce the pattern of this stationary wave in Linear Baroclinic Model (LBM).