#Enso ring review drivers

Long-term high-resolution climate proxies are therefore of great importance to extend climate information into the past and to evaluate the present climate dynamics in multicentennial time scales.

#Enso ring review drivers

This is further compounded by the high interannual and spatial precipitation variability in the region due to its complex topography and the multitude of climate drivers (Vuille & Keimig, 2004). There are few instrumental records of climate in tropical South America prior to 1950, especially in the high Andes including the Altiplano. At interannual scales, this moisture transport to the Altiplano from the Amazon Basin is greatly influenced by sea surface temperatures (SST) in the tropical Pacific (Sulca etВ al., 2018) with below (above) normal precipitation during El NiГ±o (La NiГ±a) years (Vuille, 1999). Thus, most precipitation (i.e., 75%вЂ“90%) in the Altiplano falls during the austral summer (December to March Garreaud etВ al., 2003 Vuille & Keimig, 2004), coincident with the mature phase of SASM from December to February (Raia & Cavalcanti, 2008), although occasional winter snowfall sourced from the Pacific is possible (Vuille & Ammann, 1997). Moisture is recycled over the Amazon basin before being transported toward the Altiplano (Garreaud, 1999 Segura etВ al., 2020). This moisture originates in the Atlantic Ocean and is transported toward the Amazon Basin by easterly trade winds during the austral summer (Lenters & Cook, 1997). The Bolivian High blocks the atmospheric circulation from the west, allowing the mid-to upper-level easterly winds to entrain near-surface upslope flow and moisture transport from the Amazon basin toward the Altiplano (Garreaud etВ al., 2003).

The buildup of the Bolivian High, an anticyclonic system situated over Bolivia, during the austral summer is a key atmospheric feature associated with the SASM. The South American Summer Monsoon (SASM) system dominates most of the South American seasonal hydroclimate (Marengo etВ al., 2012 Vuille etВ al., 2012). Thus, understanding hydroclimatic changes in the Altiplano is of great importance to assess the vulnerability of natural habitats and human activities to water scarcity. Some studies (Minvielle & Garreaud, 2011 Neukom etВ al., 2015) have projected a future increase in drought over the Altiplano, although the assumptions on which these projections were based have recently been questioned (Segura etВ al., 2020). Our findings are relevant for generating robust hydroclimate reconstructions in the Central Andes to improve circulation models and provide better management of water resources in tropical South America.Дroughts in the South American Altiplano, a semiarid high-elevation plateau located in the Central Andes, affect millions of people and produce large economic losses across the Andes and the adjacent arid lowlands (Canedo-Rosso etВ al., 2021). tarapacana Оґ 18O TR reflects the atmospheric processes transporting moisture to the Altiplano and the influence of local evaporation. We suggest that Оґ 18O TR is likely affected by soil evaporation and leaf transpiration due to the high solar radiation and aridity in the Altiplano, leading to an enrichment in Оґ 18O TR values with a more pronounced effect at the more arid sites. tarapacana Оґ 18O TR from 1950 to present and find that it registers precipitation changes in the Altiplano and the El NiГ±o - Southern Oscillation (ENSO). tarapacana grows in the South American Altiplano from 16В°S to 23В°S at very high elevations (up to 5,100В m a.s.l), making it the highest elevation tree species worldwide. tarapacana tree-ring stable oxygen isotope ( Оґ 18O TR) chronologies and analyze their value as environmental records for this region.

Understanding past climatic changes in the Central Andes in tropical South America is of great importance to contextualize current hydroclimatic conditions.