Past Climates of Atacama Desert

The Atacama is the driest warm desert on the planet yet the geological evidence indicate it was far more humid in the past. Factors such as Humboldt ocean current and orogenic effect of the Andes are said to contribute to it's extreme aridity today.  How these factors and their influence on the hydroclimate of Atacama changed over geological time remains poorly understood.

As part of the CRC1211 project - Earth,Evolution at dry limits - we investigate the key drivers of Atacama hydroclimate and the mechanisms of land–ocean coupling that shape them using the stable-water-isotope-enabled AWI Earth System Model (AWI-ESM-wiso). The set up consists of coupled Atmosphere (ECHAM) and ocean(FESOM) models with Water ISOtope (WISO) model which simulates absolute concentrations of  H$_2$$^{16}$O, H$_2$$^{18}$O, and D$_2$$^{16}$O in the atmosphere, ocean and ice.

We examine climate conditions across four time periods: the Miocene, the Last Glacial Maximum, the Last Interglacial, and the Mid-Holocene. We investigate how the Humbolt current have changed during this time to understand its effect on precipitation over Atacama. Our results reveal distinct shifts in moisture-transport pathways and moisture sources to the Atacama throughout the time intervals. To assess model performance, we compare simulated δ¹⁸O values with measured δ¹⁸O from foraminifera.