A contracting Intertropical Convergence Zone during the Early Heinrich Stadial 1

Despite the fact that the response of tropical hydroclimate to North Atlantic cooling events during the Heinrich Stadial 1 (HS1) has been extensively studied in African, South American and Indonesia, the nature of such responses remains debated. Here we investigate the tropical hydroclimate pattern over the Indo-Asian-Australian monsoon region during the HS1 by integrating hydroclimatic records, and examining a delta O-18(seawater) record from Globigerinoides ruber (white) in the tropical Indian Ocean. Our findings indicate that tropical hydrological conditions were synchronously arid in both hemispheres during the early HS1 (similar to 18.3-16.3 ka) in the Indo-Asian-Australian monsoon region, except for a narrow, wet hydrological belt in northern low latitudes, suggesting the existence of a contracted tropical precipitation belt at that time. This study reveals that the meltwater discharge and resulting changes in global temperatures and El Nino exerted a profound influence on the tropical hydroclimate in the Indo-Asian-Australian monsoon region during the early HS1.

Automated summary

Despite extensive studies in Africa, South America, and Indonesia, the response of tropical hydroclimate to North Atlantic cooling events during the Heinrich Stadial 1 (HS1) remains debated. This study investigates the tropical hydroclimate pattern in the Indo-Asian-Australian monsoon region during the HS1 by integrating hydroclimatic records and analyzing a delta O-18(seawater) record. The findings show that the tropical hydrological conditions were arid in both hemispheres during the early HS1, except for a narrow, wet belt in northern low latitudes.