Precipitation patterns and variability in Tropical Americas during the Holocene

Abstract

The Tropical Americas (TA) have monsoons as the dominant feature of their hydroclimate. Precipitation in this region is influenced by the American Monsoon System (AMS). Throughout the Holocene, several global climate changes occurred that modified precipitation patterns in this region. Here we identify a general trend of increasing precipitation in the TA over the last 11,700 years. We analyzed different precipitation datasets, as paleorecords from lake sediments and speleothems, and Transient Climate Simulation of the Last 21,000 Years (TraCE-21ka) model results. We also identified occasional shifts in the TA's precipitation during the Holocene, with variations in the pattern of precipitation anomalies around 9,000 to 8,000 years, corroborated by high-energy wavelet analysis signals detected before 7,710 years. These results show that TA's precipitation was influenced by the final collapse of the North American ice sheets, accelerated by increased summer insolation in Northern Hemisphere (NH).