What Speleothems Tell Us about Long-Term Rainfall Oscillation throughout the Holocene on a Planetary Scale

Within the context of anthropogenic warming, rainfall oscillations may induce especially important societal impacts worldwide. In this article, we propose to study potential underlying mechanisms related precipitation changes on a planetary scale by taking advantage recent theory Rossby waves long periods winding around subtropical gyres, Gyral Waves (GRWs). The stable oxygen isotopic compositions speleothems are used regionalize and reconstruct evolution long-term oscillation during Holocene. method applied here consists in estimating wavelet power dated series composition (δ18O) within period bands representative subharmonic modes. Our findings highlight: (1) hydrological processes resulting from friction between North Equatorial Current (NEC) Counter (NECC) explain weakening ENSO activity mid-Holocene, (2) quasi-resonance equatorward migration summer Inter Tropical Convergence Zone (ITCZ) Holocene, because progressive decrease thermal gradient low high latitudes gyres. results suggest that spatial temporal variations amplitude both acceleration/deceleration phases western boundary currents shrinkage Hadley cell. latitudinal shift ITCZ response is utmost importance predicting expansion deserts warming.