The Silk Road Teleconnection Pattern in SAMIL2.0

Abstract

Two modes of the Silk Road pattern were investigated using NCEP2 reanalysis data and the simulation produced by the LASG/IAP AGCM SAMIL2.0 (Spectral Atmospheric General Circulation Model version 2.0) model, which was forced by the observed sea surface temperature (SST). The horizontal distributions of both modes were reproduced reasonably well by the simulation, with pattern correlation coefficients of 0.63 and 0.62 for the first and second modes, respectively. The wave train was maintained by barotropic energy conversion (denoted as CK) and baroclinic energy conversion (denoted as CP) from the mean flow. The spatial pattern of CK was not reproduced, whereas the reproduction of CP was reasonable. Since CP is more efficient than CK, it can be concluded that the spatial patterns of the Silk Road pattern were well reproduced. Interestingly, the temporal phase of the second mode was well captured by a single-member simulation. However, further analysis of other ensemble runs demonstrated that the successful reproduction of the temporal phase was the result of internal variability rather than a sign of SST forcing.