Teleconections between tropics and extra-tropics of South America

Abstract

The South America Monsoon System (SAMS) is the climate system responsible for convection over most of tropical region in South America. Despite previous studies have described the SAMS variability in different time scales, the relationship between SAMS and ITCZ and with extratropical circulation has not been tested yet for the last millennium (Novello et al., 2012; 2016; Varma et al., 2011). Meehl et al. (2009) reported that peaks in solar forcing increase the energy input to the surface ocean at subtropical latitudes, thereby enhancing evaporation and near-surface moisture, which is carried by the trade winds to the convergence zones. Through this mechanism convective activity in the regions influenced by the upward branches of Hadley cell can be intensified, resulting in strengthened regional tropical precipitation regimes due to enhanced solar forcing (van Loon et al., 2004). This change in the position of the Intertropical Convergence Zone (ITCZ) and the Southwesterly (SW), could modulate the intensity of SAMS. To test this teleconnection between these climate systems new paleoclimate records from non-explored study sites are required. The understanding of SAMS and ITCZ variability during the last millennia have been improved by studies involving ´18O and trace elements on speleothems. On the other hand, the absence of cave records in southern South America for paleoclimate studies is counterbalanced by long tree rings records in Chile and Argentina. For the current project, we propose the study of speleothems in different regions of SAMS and ITCZ domains together with samples from regions climatically under influence of SW and cold fronts at higher latitudes, in order to identify the relationship between SAMS/ITCZ variability with extra tropical atmospheric circulation in South America. (AU)