Annular variations in moisture transport mechanisms and the abundance of δ18O in Antarctic snow

Abstract

Water isotopes are commonly used as indicators of climate state even though many biases and variations in processes affecting the polar signal have not been quantified. Results from the Melbourne University General Circulation Model suggest the annual cycle explains half of the monthly δ18O variance, and a semiannual variation contributes more than 15 in places. Eddy moisture convergence drives gross accumulation, while stationary flux allows sublimation of 25-30% of the precipitation. Part of the monthly anomaly variance is associated with a dominant annular disturbance in the circulation. This oscillatory mode alters the character of the transport processes through changes to the preferred..