Silk Road Pattern on the Intraseasonal Time Scale

Based on reanalysis data from 1968 to 2021, this study investigates the characteristics of Silk Road Pattern (SRP), a teleconnection pattern embedded in the Asian jet during summer, on the intraseasonal timescale. Results showed that the 10–30-day oscillations are the main component of SRP intraseasonal variability. The results of correlation for the base points along the jet axis indicate that the SRP on the 10–30-day timescale, hereafter referred to as the Bi-weekly Silk Road Pattern Oscillation (BSRP), is characterized by 3 alternatively-signed cells of 200-hPa meridional wind anomalies. The teleconnection patterns are highly consistent, no matter with the location of base points, suggesting that the BSRP is not geographically phase-locked, i.e., the BSRP has no preferred locations in the zonal direction, which is quite different with the SRP on the interannual timescale. Therefore, we “merge” the teleconnection patterns for the various base points into a composite pattern, and analyze the composite pattern to highlight the common features. The analyzed results demonstrate that the BSRP propagates eastwards of, and the speed of energy dispersion is estimated to be approximately 25° per day. In addition, the SRP obtains energy from the basic flows through the baroclinic energy conversion. On the other hand, barotropic energy conversion is weak and shows little variation with the change of longitude, failing to contribute to phase locking. Finally, we also explored the climatic impact of BSRP and found that the BSRP can induce remarkable precipitation and temperature anomalies.