Rainfall variations in central Indo-Pacific over the past 2,700 y

• Tropical rainfall variability is closely linked to meridional shifts of the Intertropical Convergence Zone ( ITCZ) and zonal movements of the Walker circulation. The characteristics and mechanisms of tropical rainfall variations on centennial to decadal scales are, however, still unclear. Here, we reconstruct a replicated stalagmite-based 2,700-y-long, continuous record of rainfall for the deeply convective northern central Indo-Pacific ( NCIP) region. Our record reveals decreasing rainfall in the NCIP over the past 2,700 y, similar to other records from the northern tropics. Notable centennial-to decadal-scale dry climate episodes occurred in both the NCIP and the southern central Indo-Pacific ( SCIP) during the 20th century [ Current Warm Period ( CWP)] and the Medieval Warm Period ( MWP), resembling enhanced El Nino-like conditions. Further, we developed a 2,000-y-long ITCZ shift index record that supports an overall southward ITCZ shift in the central Indo-Pacific and indicates southward mean ITCZ positions during the early MWP and the CWP. As a result, the drying trend since the 20th century in the northern tropics is similar to that observed during the past warm period, suggesting that a possible anthropogenic forcing of rainfall remains indistinguishable from natural variability.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Keyword

central Indo-Pacific

rainfall

ENSO

ITCZ

stalagmite

Publication and Content Type

ref (subject category)

art (subject category)