Reconstructed droughts for the southeastern Tibetan Plateau over the past 568 years and its linkages to the Pacific and Atlantic Ocean climate variability

Abstract

We present a Palmer Drought Severity Index reconstruction (r = 0.61, P < 0.01) from 1440 to 2007 for the southeastern Tibetan Plateau, based on tree rings of the forest fir (Abies forrestii). Persistent decadal dry intervals were found in the 1440s-1460s, 1560s-1580s, 1700s, 1770s, 1810s, 1860s and 1980s, and the extreme wet epochs were the 1480s-1490s, 1510s-1520s, 1590s, 1610s-1630s, 1720s-1730s, 1800s, 1830s, 1870s, 1930s, 1950s and after the 1990s. Comparisons of our record with those identified in other moisture related reconstructions for nearby regions showed that our reconstructed droughts were relatively consistent with those found in other regions of Indochina, suggesting similar drought regimes. Spectral peaks of 2.3-5.5 years may be indicative of ENSO activity, as also suggested by negative correlations with SSTs in the eastern equatorial and southeastern Pacific Ocean. Significant multidecadal spectral peaks of 29.2-40.9 and 56.8-60.2 years were identified. As indicated by the spatial correlation patterns, the decadal-scale variability may be linked to SST variations in the northern Pacific and Atlantic Oceans.