## 3 Results
### Silkroad Pattern (SRP) and Large-Scale Circulation  
Streamline flow and meridional wind anomalies are important factors for cyclogenesis. The Silkroad pattern (SRP) can be explained well by the stationary Rossby wave dynamics and the interaction between stationary waves and the basic flow, as documented in [PERSON] and [PERSON] [39]. Rossby wave ray theory ([PERSON] and [PERSON] [40]) suggested that the potent wasesterly jet acts as the waveguide and confines the waves within it, causing convection.  
The meridional wind anomalies at 200 hPa show changes in upper-level circulation patterns, which are important for steering cyclonic systems (Figure 11a-c). The streamline flow patterns suggest that upper-level winds became more favorable for TC development during the last decade. To explore the large-scale anomalous circulation pattern that  
Figure 10: Decadal variability of OLR (W/m\({}^{2}\)) anomalies during the OND seasons of (**a**) 1992–2002, (**b**) 2002–2011, and (**c**) 2012–2021; (**d–f**) are the same as (**a–c**), but for the rainfall (mmd\({}^{-1}\)) anomalies derived from the GPCP observations.  
influences Indian post-monsoon rainfall, Figure 11 shows the 200 hPa horizontal wind anomalies for three decades: 1992-2001, 2002-2011, and 2012-2021 respectively. The anomalous circulation is characterized by a distinct wave pattern propagating along the Asian wasterly jet from the North Atlantic to East Asia. This pattern is very similar to the SRP. Due to the warming over the Indian Ocean, the shift in the Asian wasterly jet and associated high-low-high pattern is also one of the reasons for a change in the regional climate of South Asia.  
Hadley circulation changes, plotted for the AS region, reveal stronger ascending motion during the 2012-2021 period, particularly over the AS, supporting the increased TC formation in recent years (Figure 11d-f). It can also be noted that the Hadley circulation (HC) during the OND season over three decades has varied in strength. The HC strength has strengthened in recent decades in the AS region. The changes in the intensity of the HC may be dependent on the strong warming over the AS. The positive anomaly of HC has shown significant shifting from the equator to 15\({}^{\circ}\) N. However, some studies have shown a decrease in the strength of the Hadley cell in recent decades over the Indian subcontinent, especially over the Indian landmass [41].  
The Subtropical Westerly Jet Stream (STWJ) plays a key role in shaping the weather and climate of the Indian subcontinent. It shifts northward during summer, facilitating the onset of the southwesterly monsoon, while its southward retreat influences monsoon withdrawal. Climate change has caused the STWJ to exhibit both poleward and equatorward shifts, driven by warming in the tropical upper levels and changes in mid-latitude eddies [42]. The interannual variability of the STWJ is influenced by large-scale climate drivers such as ENSO and the Indian Ocean Dipole, affecting the timing and extent of monsoon rainfall. Additionally, the Rossby wave train along the STWJ guides moisture transport, leading to extreme rainfall  
Figure 11: Streamline flow and meridional wind speed (shaded; ms\({}^{-1}\)) anomalies at 200 hPa and Hadley circulation plotted by averaging the winds over the Arabian Sea region 60–80 E for three decades, (**a,d**) 1992–2001, (**b,e**) 2002–2011, and (**c,f**) 2012–2021, valid for the OND season, derived from ERA5 reanalysis.  
events, particularly during the pre- and post-monsoon periods [43]. Figure 12a-c show an intensification and widening of the north-south direction of the STWJ from the first decade (1992-2001) to the last decade (2012-2021). Such variations in the jet stream pattern can significantly influence the low-pressure system and steer it northward direction.