Heavy Water Isotope Precipitation in Inland East Antarctica Accompanied
by Strong Southern Westerly Winds during the Last Glacial Maximum
Abstract
Stable water isotope signals in inland Antarctic ice cores have provided
wealth of information about past climates. This study investigated
atmospheric circulation processes that influence precipitation isotopes
in inland Antarctica associated with atmospheric circulations in the
southern mid-latitudes during the Last Glacial Maximum (LGM,
~21 000 year ago). We simulated this climate period
using circulation model (MIROC5-iso) forced with different sea surface
boundary conditions. Our results showed a steepened meridional sea
surface temperature gradient in the southern mid-latitudes associated
with a strengthening of the southern westerlies. This change in the
atmospheric circulation enhanced the intrusion of warm and humid air
from low latitudes that contributes to precipitation events, inducing
heavy isotope precipitation inland East Antarctica. Our results suggest
that the representation of past southern westerlies can be constrained
using water isotopic signals in Antarctic ice cores.