Vincent Montade

Teleconnection between the Intertropical Convergence Zone and southern westerly winds throughout the last deglaciation

Comparison of environmental changes between northeastern Brazil and western Patagonia during the last deglaciation reveals concomitant trends in moisture from the Intertropical Convergence Zone (ITCZ) and southern westerly winds (SWW). The data confirm an atmospheric teleconnection between the ITCZ and SWW, associated with Atlantic Meridional Overturning Circulation (AMOC) variations. When the AMOC decreases, both the ITCZ and the SWW shift southward; they shift northward when the AMOC increases. Climate simulations in which the AMOC is made to vary agree with this general pattern. Additional experiments performed with an atmosphere-only model show that the tropical Atlantic is a key area in promoting relationships between the AMOC, ITCZ, and SWW. Our data show that this mechanism, which transfers climate changes between low and middle latitudes to high latitudes in the Southern Hemisphere, acted throughout the abrupt climatic events of the last deglaciation.

Late Quaternary ecotone change between sub-alpine and montane forest zone on the leeward northern slope of Mt. Kilimanjaro

Tropical montane forests are crucial for providing many services for fastgrowing local human populations (Gradstein, Homeier, & Gansert, 2008). Among the essential resources provided by tropical montane forests, fresh water is one of the most important. In particular, air masses at elevation generate fog and strong orographic precipitation contributing 50% to −90% of total water discharges for the lowlands in tropical semiarid regions (Viviroli & Weingartner, 2004). Such conditions are typical for East African mountains such Received: 9 November 2017 | Accepted: 1 April 2018 DOI: 10.1111/jvs.12639