Observed regional and climatological associations between spring and summer precipitation over northern central Eurasia

Abstract

Regional patterns of association between spring and summer precipitation over northern central Eurasia are examined based on 60 years (1936–1995) of station precipitation records. Rotated principal component analysis and correlation analysis are performed to reveal regional teleconnections. This study found that summer precipitation is positively correlated with spring precipitation over areas east of the Caspian Sea and west of China. Summer precipitation over and west of the northern Ural Mountains is positively correlated, while summer precipitation over central Siberia is negatively correlated to spring precipitation over northern European Russia. Persistent summer wind anomalies in the middle and lower troposphere are found to be associated with spring precipitation conditions and thus may be responsible for the observed summer precipitation anomalies. Also, orographic lifting may be another contributor to enhanced local moisture recycling in the identified areas. Knowledge of regional patterns of association between summer and spring precipitation will help us to better predict summer precipitation anomalies, especially regarding the possible persistence of droughts.