Warm-season annual to decadal temperature variability for Hokkaido, Japan,inferred from maximum latewood density (AD 1557-1990) and ring width data (AD 1532-1990)

We present a warm season (April-September) temperature reconstruction for A sahikawa, north central Hokkaido, Japan for AD 1557-1990. The reconstructio n, which accounts for 34% of the temperature variance from 1925-1990, is ba sed on maximum latewood density data from Saghalin spruce (Picea glehnii) g rowing at timberline (1340-1390 m) at Mount Asahidake, Hokkaido. We only pr esent a high frequency (prewhitened or white noise) version of the reconstr uction because there is an unexplained offset in the mean between the actua l and estimated temperature data for an earlier period of overlap from 1891 -1924. The coldest summer in the reconstruction is 1718, for which the esti mated value is 12.89 degrees C, nearly four standard deviations (SD) below the mean. A colder-than-average year is reconstructed for 1641 (13.30 degre es C, nearly 3 SD below mean), following the eruption of Komagatake, Hokkai do which began in July, 1640. The Asahikawa density chronology, shows decad al modes of variation with statistically significant spectral peaks prior t o around 1850. A tree-ring width chronology for this same site (AD 1532-199 0) is in phase with a tree-ring width record from central Kamchatka prior t o around 1850, but out of phase since that time. This pattern suggests, as has been hypothesized for temperature-sensitive tree-ring records from the eastern Pacific sector (Alaska and Patagonia), that a decadal mode of clima te variation was more dominant in the Pacific sector prior to about 1850, a fter which a higher frequency (ENSO-type) mode may have become more pronoun ced, at least until recent decades. Additional data from the northwestern P acific is needed to compare to these findings.