Impacts of Soil Moisture-Atmosphere Coupling on the Silk Road Pattern in Summer

Based on CMIP6 model simulations, this study investigates the impacts and mechanisms of soil moisture-atmosphere coupling (SA) on the Silk Road Pattern (SRP) in the Northern Hemisphere summer. A comparison between LS3MIP (uncoupled) and AMIP (coupled) experiments reveals that weakened SA alters both the position and intensity of the SRP wave train centers, showing a “+-+-” anomalous distribution around 40°N (in meridional wind pattern). The results indicate that the SA in the Tibetan Plateau (TP) region play an important role in the distribution of SRP. Furthermore, SA significantly influences the SRP wave train characteristics in mid-latitude regions by regulating surface heat fluxes and atmospheric heat sources (<Q1>), with notable geopotential height anomalies over the Caspian Sea, the TP and Northeast Asia. Specifically, due to the weakening of the SA, the cooling effect over the TP induces subsidence, while the regions surrounding the Caspian Sea and Northeast Asia exhibit heat source anomalies accompanied by ascending motion. This results in a corresponding "+-+" geopotential height anomaly pattern associated with the SRP, ultimately influencing the wave train distribution of SRP. Thus, SA is an important factor driving the variability of the SRP wave train.