Relationship between early summer precipitation in Japan and the El Niño-Southern and Pacific Decadal Oscillations over the past 400 years

Abstract

The El Niño–Southern Oscillation (ENSO) appears to strongly influence East Asian Summer Monsoon (EASM) rainfall, but the relatively short instrumental rainfall record hinders the development of a longer-term understanding of this teleconnection. To partially overcome this issue, here we reconstruct precipitation from tree-ring oxygen isotopes (δ18O) in central Japan during AD 1612–1935. Our results indicate that tree-ring cellulose δ18O is significantly correlated with May–June (MJ) precipitation, allowing us to investigate the link between the EASM summer rainfall and ENSO over the past 400 years. Time- and frequency-domain comparison of the tree-ring δ18O record and recent ENSO reconstructions reveal a common high-frequency (3–8 year) variability that characterized the mid-17th, late 18th and late 19th centuries. Similar analyses of instrumental MJ precipitation and several ENSO indexes during the 20th century indicate that this high-frequency oscillation reappeared from AD 1980. Comparison of ENSO and Pacific Decadal Oscillation (PDO) indexes indicates that the ENSO–EASM teleconnection is strong when ENSO variance is high, and the PDO phase may modulate the ENSO–EASM relationship over the past 400 years.