Synergistic Effects of Multi‐Timescale Atmospheric Teleconnections on Spring Monthly Droughts in Central‐Eastern China

Abstract This study investigates the spring monthly drought variations in central‐eastern China (CEC) and the possible synergistic effects of multi‐timescale atmospheric teleconnections. During March, CEC drought conditions are jointly influenced by high‐frequency and low‐frequency variations of the Scandinavian teleconnection (SCA). When these multi‐timescale atmospheric teleconnections align in phase, a reinforced dipole atmospheric circulation anomaly (high‐pressure over Lake Balkhash and low‐pressure over Japan) causes decreased moisture and surface warming in the CEC, favoring less precipitation and more potential evapotranspiration over there and consequently causing pronounced droughts. When these atmospheric teleconnections align out of phase, the above‐mentioned dipole atmospheric circulation anomaly weakens significantly, and there is a normal condition in the CEC. In April and May, the high‐frequency drought variations are associated with both the SCA and the West Pacific teleconnection, whereas the low‐frequency variations are modulated by the SCA and the North Atlantic Oscillation. In‐phase alignment of the above‐mentioned multi‐timescale atmospheric teleconnections could amplify the dipole atmospheric circulation over Lake Balkhash and Japan, which can significantly influence the dry conditions in CEC by modulating local precipitation and evapotranspiration. In comparison, out‐of‐phase alignment cannot affect the drought conditions in the region.