A continuous 3000-year precipitation record of ENSO variability during LGM from a stalagmite in Nanjing

摘要

A glacial stalagmite chronology from Nanjing has been established by the TIMS-U series dating and annual band counting methods. The annually layering sequence spanning the 3000-year period from 18179 to 14900 calendar years before the present (aBP) was analyzed for evidence of East Asian summer monsoon precipitation variability during the Last Glacial Maximum (LGM). Power spectral analysis of the sequence shows a distinct interannual (2 — 7 years) band of enhanced variability suggestive of El Nino-Southern Oscillation (ENSO) teleconnections into East China during the LGM when climatic boundary conditions were different from those of today. The lower frequency bands (4 — 7 years) variability becomes weaker from 18179 to 14900 aBP, supporting the precession forcing model. The reappearance of the ENSO band in the coldest climatic boundary conditions during the Heinrich Event 1, however, suggests the stimulation of the enhanced East Asia whiter monsoon to the El Nino events.