Abstract. A high-frequency and precise ultrasonic sounder was used to record precipitated/deposited snow and drift events over a 3 yr period (17 January 2005 to 4 January 2008) at the Eagle automatic weather station (AWS) site. Through a comparison of the meteorological data with snow pit chemical/isotopic dating results, the snowdrift process effect during snow accumulation was assessed. We believe that ice/firn cores are the most important proxies of climate and the environment because of their high resolution and their preservation of historical greenhouse gas levels, although their limitations and measurement uncertainties must be taken into account, due to the event-driven snow dominates the snow deposition. This study found a difference between two dating results of up to 12 months for a ~ 95 cm snow pit, where the annual snow accumulation rate is 30.3 cm. A weakness is also indicated when simulating the surface mass balance in Antarctica.