Different impacts of spring tropical Atlantic SST anomalies on Eurasia spring climate during the periods of 1970–1995 and 1996–2018

Abstract

We investigate impacts of spring tropical Atlantic sea surface temperature anomalies (SSTAs) on Eurasian spring climate during the period of 1961–2018, using both observations and Community Atmosphere Model (CAM) simulations. Observations during the study period show that the tropical Atlantic sea surface temperature (SST) experienced an abrupt warming around 1995. Distinctive impacts of spring tropical Atlantic SSTAs on Eurasian spring surface air temperature (SAT) and precipitation during the period 1970–1995 (P1) and 1996–2018 (P2) are revealed. During P1, spring tropical Atlantic SSTAs were highly correlated with spring SAT anomalies over Northern Europe, Southeast China, and Indochina Peninsula. These high correlations disappeared during P2; instead, high correlations dominated over North-Northeastern China, and Central Siberia in spring. The high correlation patterns between spring tropical Atlantic SSTAs and spring Eurasian precipitation of these two periods also differed. The interannual relationship between spring tropical Atlantic SSTAs and Eurasian SAT/precipitation during P2 was mainly due to the existence of an anomalous atmospheric wave train across the tropical Atlantic and Eurasia, which was absent during P1. These observational results are confirmed by a set of CAM simulations.